<?php
/**
 * @file include/items.php
 * @brief Items related functions.
 */

use Code\Lib\Libzot;
use Code\Lib\Libsync;
use Code\Lib\AccessList;
use Code\Lib\Activity;
use Code\Lib\ActivityStreams;
use Code\Lib\Apps;
use Code\Lib\Enotify;
use Code\Lib\Channel;
use Code\Lib\LanguageDetect;
use Code\Lib\MarkdownSoap;
use Code\Lib\MessageFilter;
use Code\Lib\Config;
use Code\Lib\IConfig;
use Code\Lib\ObjCache;
use Code\Lib\PConfig;
use Code\Lib\LibBlock;
use Code\Lib\ThreadListener;
use Code\Lib\Tombstone;
use Code\Access\PermissionLimits;
use Code\Access\PermissionRoles;
use Code\Access\AccessControl;
use Code\Daemon\Run;
use Code\Extend\Hook;

require_once('include/feedutils.php');
require_once('include/photo_factory.php');


/**
 * @brief Collects recipients.
 *
 * @param array $item
 * @param bool $private_envelope
 * @return array containing the recipients
 */
function collect_recipients($item, &$private_envelope) {

    $private_envelope = (bool)intval($item['item_private']);
    $recipients = [];

    if ($item['allow_cid'] || $item['allow_gid'] || $item['deny_cid'] || $item['deny_gid']) {
        // it is private
        $recipients = item_get_recipients($item);
        $private_envelope = true;
    }
    else {

        // if the post is marked private but there are no recipients and public_policy/scope = self,
        // only add the author and owner as recipients. The ACL for the post may live on the hub of
        // a different clone. We need to get the post to that hub.

        // The post may be private by virtue of not being visible to anybody on the internet,
        // but there are no envelope recipients, so set this to false.

        $private_envelope = false;

        $r = q("select abook_xchan, xchan_network from abook left join xchan on abook_xchan = xchan_hash where abook_channel = %d and abook_self = 0 and abook_pending = 0 and abook_archived = 0 ",
            intval($item['uid'])
        );
        if ($r) {
            foreach ($r as $rv) {
                $recipients[] = $rv['abook_xchan'];
            }
        }

        // Forward to thread listeners, *unless* there is even a remote hint that the item
        // might have some privacy attached. This could be (for instance) an ActivityPub DM
        // in the middle of a public thread. Unless we can guarantee beyond all doubt that
        // this is public, don't allow it to go to thread listeners.

        if (! intval($item['item_private'])) {
            $r = array_merge(ThreadListener::fetch_by_target($item['parent_mid']),
                ThreadListener::fetch_by_target(str_replace('/activity/','/item/',$item['parent_mid']))
            );
            if ($item['mid'] !== $item['parent_mid']) {
                $r = array_merge($r, ThreadListener::fetch_by_target($item['mid']),
                    ThreadListener::fetch_by_target(str_replace('/activity/','/item/',$item['mid']))
                );
            }
            if ($r) {
                foreach ($r as $rv) {
                    if (! in_array($rv['portable_id'],$recipients)) {
                        $recipients[] = $rv['portable_id'];
                    }
                }
            }

            // We've determined this is public. Send it also to the system channel.

            $sys = Channel::get_system();
            if ($sys && intval($item['uid']) !== intval($sys['channel_id'])) {
                $recipients[] = $sys['channel_hash'];
            }

        }

        // Add the authors of any posts in this thread, if they are known to us.
        // This is specifically designed to forward wall-to-wall posts to the original author,
        // in case they aren't a connection but have permission to write on our wall.
        // This is important for issue tracker channels. It should be a no-op for most channels.
        // Whether they will accept the delivery is not determined here, but should
        // be taken into account by zot:process_delivery()

        $r = q("select author_xchan from item where parent = %d",
            intval($item['parent'])
        );
        if ($r) {
            foreach ($r as $rv) {
                if (! in_array($rv['author_xchan'],$recipients)) {
                    $recipients[] = $rv['author_xchan'];
                }
            }
        }

    }

    // This is a somewhat expensive operation but important.
    // Don't send this item to anybody who doesn't have the deliver_stream permission

    $recipients = check_deliver_permissions($item['uid'],$recipients);

    // Add both the author and owner (if different).

    $recipients[] = $item['author_xchan'];

    if ($item['owner_xchan'] != $item['author_xchan']) {
        $recipients[] = $item['owner_xchan'];
    }

    return $recipients;
}

function item_get_recipients($item) {

    $allow_people = expand_acl($item['allow_cid']);
    $allow_groups = AccessList::expand(expand_acl($item['allow_gid']));

    $recipients = array_values(array_unique(array_merge($allow_people,$allow_groups)));

    // if you specifically deny somebody but haven't allowed anybody, we'll allow everybody in your
    // address book minus the denied connections. The post is still private and can't be seen publicly
    // as that would allow the denied person to see the post by logging out.

    if ((! $item['allow_cid']) && (! $item['allow_gid'])) {
        $r = q("select * from abook where abook_channel = %d and abook_self = 0 and abook_pending = 0 and abook_archived = 0 ",
            intval($item['uid'])
        );

        if ($r) {
            foreach ($r as $rr) {
                $recipients[] = $rr['abook_xchan'];
            }
        }
    }

    $deny_people  = expand_acl($item['deny_cid']);
    $deny_groups  = AccessList::expand(expand_acl($item['deny_gid']));

    $deny = array_values(array_unique(array_merge($deny_people,$deny_groups)));

    // Don't deny anybody if nobody was allowed (e.g. they were all filtered out)
    // That would lead to array_diff doing the wrong thing.
    // This will result in a private post that won't be delivered to anybody.

    if ($recipients && $deny) {
        $recipients = array_diff($recipients,$deny);
    }
    return $recipients;
}

function comments_are_now_closed($item) {

    $x = [
        'item' => $item,
        'closed' => 'unset'
    ];

    /**
     * @hooks comments_are_now_closed
     *   Called to determine whether commenting should be closed
     *   * \e array \b item
     *   * \e boolean \b closed - return value
     */

    Hook::call('comments_are_now_closed', $x);

    if ($x['closed'] !== 'unset') {
        return $x['closed'];
    }

    if ($item['comments_closed'] > NULL_DATE && datetime_convert() > $item['comments_closed']) {
        return true;
    }

    return false;
}

function item_normal() {
    return " and item.item_hidden = 0 and item.item_type = 0 and item.item_deleted = 0
        and item.item_unpublished = 0 and item.item_delayed = 0 and item.item_pending_remove = 0
        and item.item_blocked = 0 and item.obj_type != '" . ACTIVITY_OBJ_FILE . "' ";
}

function item_normal_draft() {
    return " and item.item_hidden = 0 and item.item_type = 0 and item.item_deleted = 0
        and item.item_pending_remove = 0 and item.item_blocked = 0 and item.obj_type != '" . ACTIVITY_OBJ_FILE . "' ";
}

function item_normal_search() {
    return " and item.item_hidden = 0 and item.item_type in (0,3,6,7) and item.item_deleted = 0
        and item.item_unpublished = 0 and item.item_delayed = 0 and item.item_pending_remove = 0
        and item.item_blocked = 0 and item.obj_type != '" . ACTIVITY_OBJ_FILE . "' ";
}

function item_normal_update() {
    return " and item.item_hidden = 0 and item.item_type = 0
        and item.item_unpublished = 0 and item.item_delayed = 0 and item.item_pending_remove = 0
        and item.item_blocked = 0 and item.obj_type != '" . ACTIVITY_OBJ_FILE . "' ";
}

function item_normal_moderate() {
    return " and item.item_hidden = 0 and item.item_type = 0 and item.item_deleted = 0
        and item.item_unpublished = 0 and item.item_delayed = 0 and item.item_pending_remove = 0
        and item.item_blocked in (0, 4) and item.obj_type != '" . ACTIVITY_OBJ_FILE . "' ";
}


/**
 * @brief
 *
 * This is a compatibility function primarily for plugins, because
 * in earlier DB schemas this was a much simpler single integer compare
 *
 * @param array $item
 */
function is_item_normal($item) {

    if (intval($item['item_hidden']) || intval($item['item_type']) || intval($item['item_deleted'])
        || intval($item['item_unpublished']) || intval($item['item_delayed']) || intval($item['item_pending_remove'])
        || intval($item['item_blocked']) || ($item['obj_type'] == ACTIVITY_OBJ_FILE)) {
        return false;
    }

    return true;
}

/**
 * @brief Decide if current observer has sufficient privileges to comment on item.
 *
 * This function examines the comment_policy attached to an item and decides if the current observer has
 * sufficient privileges to comment. This will normally be called on a remote site where perm_is_allowed()
 * will not be suitable because the post owner does not have a local channel_id.
 * Generally we should look at the item - in particular the author['abook_flags'] and see if ABOOK_FLAG_SELF is set.
 * If it is, you should be able to use perm_is_allowed( ... 'post_comments'), and if it isn't you need to call
 * can_comment_on_post()
 * We also check the comments_closed date/time on the item if this is set.
 *
 * @param string $observer_xchan
 * @param array $item
 * @return bool
 */
function can_comment_on_post($observer_xchan, $item)
{

//  logger('Comment_policy: ' . $item['comment_policy'], LOGGER_DEBUG);

    $x = [
        'observer_hash' => $observer_xchan,
        'item'          => $item,
        'allowed'       => 'unset'
    ];

    /**
     * @hooks can_comment_on_post
     *   Called when deciding whether to present a comment box for a post.
     *   * \e string \b observer_hash
     *   * \e array \b item
     *   * \e boolean \b allowed - return value
     */

    Hook::call('can_comment_on_post', $x);

    if ($x['allowed'] !== 'unset') {
        return $x['allowed'];
    }

    if (! $observer_xchan) {
        return false;
    }

    if ($item['comment_policy'] === 'none' || intval($item['item_nocomment']) || comments_are_now_closed($item)) {
        return false;
    }

    if ($observer_xchan === $item['author_xchan'] || $observer_xchan === $item['owner_xchan']) {
        return true;
    }

    switch ($item['comment_policy']) {
        case 'network: red':
        case 'network: activitypub':
        case 'public':
        case 'authenticated':
            // Anonymous folks won't ever reach this point (as $observer_xchan will be empty).
            // This means we can identify the viewer.
            return true;
        case 'any connections':
        case 'specific':
        case 'contacts':
        case '':
            // local posts only - check if the post owner granted me comment permission
            if (local_channel() && array_key_exists('owner', $item) && their_perms_contains(local_channel(), $item['owner']['abook_xchan'], 'post_comments')) {
                    return true;
            }

            if (intval($item['item_wall']) && perm_is_allowed($item['uid'], $observer_xchan, 'post_comments')) {
                return true;
            }
            break;
        case 'self':
        default:
            break;
    }

    if (strstr($item['comment_policy'], 'site:') && strstr($item['comment_policy'], App::get_hostname())) {
        return true;
    }

    return false;
}


function absolutely_no_comments($item) {

    if ($item['comment_policy'] === 'none') {
        return true;
    }

    if (intval($item['item_nocomment'])) {
        return true;
    }

    if(comments_are_now_closed($item)) {
        return true;
    }

    return false;
}

/**
 * @brief Post an activity.
 *
 * In its simplest form one needs only to set $arr['body'] to post a note to the logged in channel's wall.
 * Much more complex activities can be created. Permissions are checked. No filtering, tag expansion
 * or other processing is performed.
 *
 * @param array $arr
 * @param boolean $deliver (optional) default true
 * @returns array
 *  * \e boolean \b success true or false
 *  * \e array \b activity the resulting activity if successful
 */
function post_activity_item($arr, $deliver = true, $channel = null, $observer = null) {
    
    logger('input: ' . print_r($arr,true),  LOGGER_DATA);
    $ret = [ 'success' => false ];

    $is_comment = false;
    if ((isset($arr['parent']) && $arr['parent'] && $arr['parent'] != $arr['id']) || (isset($arr['parent_mid']) && $arr['parent_mid'] && $arr['parent_mid'] != $arr['mid'])) {
        $is_comment = true;
    }
    if (! array_key_exists('item_origin',$arr)) {
        $arr['item_origin'] = 1;
    }
    if (! array_key_exists('item_wall',$arr) && (! $is_comment)) {
        $arr['item_wall'] = 0;
    }
    if (! array_key_exists('item_thread_top',$arr) && (! $is_comment)) {
        $arr['item_thread_top'] = 1;
    }

    if (!$channel) {
        $channel = App::get_channel();
    }
    if (!$observer) {
        $observer = App::get_observer();
    }

    $arr['aid'] = ((isset($arr['aid'])) ? $arr['aid'] : $channel['channel_account_id']);
    $arr['uid'] = ((isset($arr['uid'])) ? $arr['uid'] : $channel['channel_id']);

    if (! perm_is_allowed($arr['uid'], $observer['xchan_hash'], (($is_comment) ? 'post_comments' : 'post_wall'))) {
        $ret['message'] = t('Permission denied');
        return $ret;
    }

    if (! array_key_exists('mimetype',$arr)) {
        $arr['mimetype'] = 'text/x-multicode';
    }

    if (! (isset($arr['mid']) && $arr['mid'])) {
        $arr['uuid'] = ((isset($arr['uuid'])) ? $arr['uuid'] : new_uuid());
    }
    $arr['mid']          = ((isset($arr['mid'])) ? $arr['mid'] : z_root() . '/item/' . $arr['uuid']);

    $arr['parent_mid']   = ((isset($arr['parent_mid'])) ? $arr['parent_mid'] : $arr['mid']);
    $arr['thr_parent']   = ((isset($arr['thr_parent'])) ? $arr['thr_parent'] : $arr['mid']);

    $arr['owner_xchan']  = ((isset($arr['owner_xchan']))  ? $arr['owner_xchan']  : $channel['channel_hash']);
    $arr['author_xchan'] = ((isset($arr['author_xchan'])) ? $arr['author_xchan'] : $observer['xchan_hash']);

    $arr['verb']         = ((x($arr,'verb')) ? $arr['verb'] : ACTIVITY_POST);
    $arr['obj_type']     = ((x($arr,'obj_type')) ? $arr['obj_type'] : ACTIVITY_OBJ_ARTICLE);

    if(! ( array_key_exists('allow_cid',$arr) || array_key_exists('allow_gid',$arr)
        || array_key_exists('deny_cid',$arr) || array_key_exists('deny_gid',$arr))) {
        $arr['allow_cid']    = $channel['channel_allow_cid'];
        $arr['allow_gid']    = $channel['channel_allow_gid'];
        $arr['deny_cid']     = $channel['channel_deny_cid'];
        $arr['deny_gid']     = $channel['channel_deny_gid'];
    }

    $arr['comment_policy'] = map_scope(PermissionLimits::Get($channel['channel_id'],'post_comments'));

    if (empty($arr['plink'])) {
        $arr['plink'] = $arr['mid'];
    }

    // for the benefit of plugins, we will behave as if this is an API call rather than a normal online post

    $_REQUEST['api_source'] = 1;

    /**
     * @hooks post_local
     *   Called when an item has been posted on this machine via mod/item.php (also via API).
     */
    Hook::call('post_local', $arr);

    if(x($arr, 'cancel')) {
        logger('Post cancelled by plugin.');
        return $ret;
    }

    $post = item_store($arr,$deliver);
    $post_id = 0;

    if($post['success']) {
        $post_id = $post['item_id'];
        $ret['success'] = true;
        $ret['item_id'] = $post_id;
        $ret['activity'] = $post['item'];

        /**
         * @hooks post_local_end
         *   Called after a local post operation has completed.
         *   * \e array - the item returned from item_store()
         */
        Hook::call('post_local_end', $ret['activity']);
        sync_an_item($channel ? $channel['channel_id'] : $arr['uid'], $post_id);
    }

    if($post_id && $deliver) {
        Run::Summon([ 'Notifier','activity',$post_id ]);
    }

    return $ret;
}


function validate_item_elements($message,$arr) {

    $result = ['success' => false];

    if(! array_key_exists('created',$arr))
        $result['message'] = 'missing created, possible author/owner lookup failure';

    if((! $arr['mid']) || (! $arr['parent_mid']))
        $result['message'] = 'missing message-id or parent message-id';

    if(array_key_exists('flags',$message) && in_array('relay',$message['flags']) && $arr['mid'] === $arr['parent_mid'])
        $result['message'] = 'relay set on top level post';

    if(! $result['message'])
        $result['success'] = true;

    return $result;
}


function get_item_elements($x) {

    $arr = [];

    $arr['body'] = $x['body'];
    $arr['summary'] = $x['summary'];

    $mirror = array_key_exists('revision', $x);
    $maxlen = get_max_import_size();

    if($maxlen && mb_strlen($arr['body']) > $maxlen) {
        $arr['body'] = mb_substr($arr['body'],0,$maxlen,'UTF-8');
        logger('get_item_elements: message length exceeds max_import_size: truncated');
    }

    if($maxlen && mb_strlen($arr['summary']) > $maxlen) {
        $arr['summary'] = mb_substr($arr['summary'],0,$maxlen,'UTF-8');
        logger('get_item_elements: message summary length exceeds max_import_size: truncated');
    }

    $arr['created']      = datetime_convert('UTC','UTC',$x['created']);
    $arr['edited']       = datetime_convert('UTC','UTC',$x['edited']);

    $arr['expires']      = ((x($x,'expires') && $x['expires'])
                                ? datetime_convert('UTC','UTC',$x['expires'])
                                : NULL_DATE);

    $arr['commented']    = ((x($x,'commented') && $x['commented'])
                                ? datetime_convert('UTC','UTC',$x['commented'])
                                : $arr['created']);
    $arr['comments_closed']    = ((x($x,'comments_closed') && $x['comments_closed'])
                                ? datetime_convert('UTC','UTC',$x['comments_closed'])
                                : NULL_DATE);

    $arr['title']        = (($x['title'])          ? htmlspecialchars($x['title'],          ENT_COMPAT,'UTF-8',false) : '');

    if(mb_strlen($arr['title']) > 255)
        $arr['title'] = mb_substr($arr['title'],0,255);

    $arr['uuid']         = (($x['uuid'])           ? htmlspecialchars($x['uuid'],           ENT_COMPAT,'UTF-8',false) : '');
    $arr['app']          = (($x['app'])            ? htmlspecialchars($x['app'],            ENT_COMPAT,'UTF-8',false) : '');
    $arr['mid']          = (($x['message_id'])     ? htmlspecialchars($x['message_id'],     ENT_COMPAT,'UTF-8',false) : '');
    $arr['parent_mid']   = (($x['message_top'])    ? htmlspecialchars($x['message_top'],    ENT_COMPAT,'UTF-8',false) : '');
    $arr['thr_parent']   = (($x['message_parent']) ? htmlspecialchars($x['message_parent'], ENT_COMPAT,'UTF-8',false) : '');
    $arr['approved']     = (($x['approved'])       ? htmlspecialchars($x['approved'],       ENT_COMPAT,'UTF-8',false) : '');

    $arr['plink']        = (($x['permalink'])      ? htmlspecialchars($x['permalink'],      ENT_COMPAT,'UTF-8',false) : '');
    $arr['location']     = (($x['location'])       ? htmlspecialchars($x['location'],       ENT_COMPAT,'UTF-8',false) : '');
    $arr['verb']         = (($x['verb'])           ? htmlspecialchars($x['verb'],           ENT_COMPAT,'UTF-8',false) : '');
    $arr['mimetype']     = (($x['mimetype'])       ? htmlspecialchars($x['mimetype'],       ENT_COMPAT,'UTF-8',false) : '');
    $arr['obj_type']     = (($x['object_type'])    ? htmlspecialchars($x['object_type'],    ENT_COMPAT,'UTF-8',false) : '');
    $arr['tgt_type']     = (($x['target_type'])    ? htmlspecialchars($x['target_type'],    ENT_COMPAT,'UTF-8',false) : '');

    if ($x['longlat']) {
        $coordinates = explode(' ', $x['longlat']);
        if (count($coordinates) > 1) {
            $arr['lat'] = floatval($coordinates[0]);
            $arr['lon'] = floatval($coordinates[1]);
        }
    }
    // convert AS1 namespaced elements to AS-JSONLD

    $arr['verb'] = Activity::activity_mapper($arr['verb']);

    $arr['obj_type'] = Activity::activity_obj_mapper($arr['obj_type'], $mirror);
    $arr['tgt_type'] = Activity::activity_obj_mapper($arr['tgt_type'], $mirror);

    $arr['comment_policy'] = (($x['comment_scope']) ? htmlspecialchars($x['comment_scope'], ENT_COMPAT,'UTF-8',false) : 'contacts');

    $arr['sig']          = (($x['signature']) ? htmlspecialchars($x['signature'],  ENT_COMPAT,'UTF-8',false) : '');

    // fix old-style signatures imported from hubzilla

    if($arr['sig'] && (! strpos($arr['sig'],'.'))) {
        $arr['sig'] = 'sha256.' . $arr['sig'];
    }

    $arr['obj']          = activity_sanitise($x['object']);

    if($arr['obj'] && is_array($arr['obj']) && array_key_exists('asld',$arr['obj'])) {
        $arr['obj'] = $arr['obj']['asld'];
    }

    $arr['target']       = isset($x['target']) ? activity_sanitise($x['target']) : '';

    if($arr['target'] && is_array($arr['target']) && array_key_exists('asld',$arr['target'])) {
        $arr['target'] = $arr['target']['asld'];
    }

    $arr['attach']       = activity_sanitise($x['attach']);

    $arr['replyto']      = activity_sanitise($x['replyto']);
    $arr['term']         = isset($x['tags']) ? decode_tags($x['tags']) : [];
    $arr['iconfig']      = decode_item_meta($x['meta']);

    $arr['item_private'] = 0;
    $arr['item_flags'] = 0;

    if(array_key_exists('flags',$x)) {

        if(in_array('consensus',$x['flags']))
            $arr['item_consensus'] = 1;

        if(in_array('deleted',$x['flags']))
            $arr['item_deleted'] = 1;

        if(in_array('notshown',$x['flags']))
            $arr['item_notshown'] = 1;

        if(in_array('obscured',$x['flags']))
            $arr['item_obscured'] = 1;

        // hidden item are no longer propagated - notshown may be a suitable alternative

        if(in_array('hidden',$x['flags']))
            $arr['item_hidden'] = 1;

        if(in_array('private',$x['flags']))
            $arr['item_private'] = 1;

        if(in_array('direct',$x['flags']))
            $arr['item_private'] = 2;

    }

    // Here's the deal - the site might be down or whatever but if there's a new person you've never
    // seen before sending stuff to your stream, we MUST be able to look them up and import their data from their
    // hub and verify that they are legit - or else we're going to toss the post. We only need to do this
    // once, and after that your hub knows them. Sure some info is in the post, but it's only a transit identifier
    // and not enough info to be able to look you up from your hash - which is the only thing stored with the post.

    $xchan_hash = import_author_xchan($x['author']);
    if($xchan_hash)
        $arr['author_xchan'] = $xchan_hash;
    else
        return [];

    $xchan_hash = import_author_xchan($x['owner']);
    if($xchan_hash) {
        $arr['owner_xchan'] = $xchan_hash;
    }
    else {
        return [];
    }

    // Check signature on the body text received.
    // This presents an issue that we aren't verifying the text that is actually displayed
    // on this site. We are however verifying the received text was exactly as received.
    // We have every right to strip content that poses a security risk. You are welcome to
    // create a plugin to verify the content after filtering if this offends you.

    if($arr['sig']) {

        // check the supplied signature against the supplied content.
        // Note that we will purify the content which could change it.

        $r = q("select xchan_pubkey from xchan where xchan_hash = '%s' limit 1",
            dbesc($arr['author_xchan'])
        );
        if($r) {
            if($r[0]['xchan_pubkey']) {
                if(Libzot::verify($x['body'],$arr['sig'],$r[0]['xchan_pubkey'])) {
                    $arr['item_verified'] = 1;
                }
                else {
                    logger('get_item_elements: message verification failed.');
                }
            }
            else {

                // If we don't have a public key, strip the signature, so that it won't show as invalid.
                // This won't happen in normal use, but could happen if import_author_xchan()
                // failed to load the zot-info packet due to a server failure and had
                // to create an alternate xchan with network 'unknown'

                unset($arr['sig']);
            }
        }
    }

    // Strip old-style hubzilla bookmarks
    // Do this after signature verification

    if (str_contains($x['body'], "#^[")) {
        $x['body'] = str_replace("#^[","[",$x['body']);
    }

    // if the input is markdown, remove one level of html escaping.
    // It will be re-applied in item_store() and/or item_store_update().
    // Do this after signature checking as the original signature
    // was generated on the escaped content.

    if ($arr['mimetype'] === 'text/markdown') {
        $arr['summary'] = MarkdownSoap::unescape($arr['summary']);
        $arr['body']    = MarkdownSoap::unescape($arr['body']);
    }

    if ($mirror) {

        // extended export encoding
        $arr['revision'] = $x['revision'];
        $arr['allow_cid'] = $x['allow_cid'];
        $arr['allow_gid'] = $x['allow_gid'];
        $arr['deny_cid'] = $x['deny_cid'];
        $arr['deny_gid'] = $x['deny_gid'];
        $arr['layout_mid'] = $x['layout_mid'];
        $arr['postopts'] = $x['postopts'];
        $arr['resource_id'] = $x['resource_id'];
        $arr['resource_type'] = $x['resource_type'];
        $arr['item_origin'] = intval($x['item_origin']);
        $arr['item_unseen'] = intval($x['item_unseen']);
        $arr['item_starred'] = intval($x['item_starred']);
        $arr['item_uplink'] = intval($x['item_uplink']);
        $arr['item_consensus'] = intval($x['item_consensus']);
        $arr['item_wall'] = intval($x['item_wall']);
        $arr['item_thread_top'] = intval($x['item_thread_top']);
        $arr['item_notshown'] = intval($x['item_notshown']);
        $arr['item_nsfw'] = intval($x['item_nsfw']);
        // local only        $arr['item_relay'] = $x['item_relay'];
        $arr['item_mentionsme'] = intval($x['item_mentionsme']);
        $arr['item_nocomment'] = intval($x['item_nocomment']);
        $arr['item_obscured'] = intval($x['item_obscured']);
        // local only $arr['item_verified'] = $x['item_verified'];
        $arr['item_retained'] = intval($x['item_retained']);
        $arr['item_rss'] = intval($x['item_rss']);
        $arr['item_deleted'] = intval($x['item_deleted']);
        $arr['item_type'] = intval($x['item_type']);
        $arr['item_hidden'] = intval($x['item_hidden']);
        $arr['item_unpublished'] = intval($x['item_unpublished']);
        $arr['item_delayed'] = intval($x['item_delayed']);
        $arr['item_pending_remove'] = intval($x['item_pending_remove']);
        $arr['item_blocked'] = intval($x['item_blocked']);
        $arr['item_restrict'] = isset($x['item_restrict']) ? intval($x['item_restrict']) : 0;
        $arr['item_flags'] = isset($x['item_flags']) ? intval($x['item_flags']) : 0;

    }

    return $arr;
}


function import_author_xchan($x) {

    if(! $x) {
        return false;
    }

    $arr = [
            'xchan' => $x,
            'xchan_hash' => ''
    ];
    /**
     * @hooks import_author_xchan
     *   Called when looking up an author of a post by xchan_hash to ensure they have an xchan record on our site.
     *   * \e array \b xchan
     *   * \e string \b xchan_hash - The returned value
     */
    Hook::call('import_author_xchan', $arr);
    if($arr['xchan_hash'])
        return $arr['xchan_hash'];

    $y = false;

    if((! array_key_exists('network', $x)) || in_array($x['network'], ['nomad', 'zot6'])) {
        $y = Libzot::import_author_zot($x);
    }

    // if we were told that it's a zot connection, don't probe/import anything else
    if(array_key_exists('network', $x) && in_array($x['network'], ['nomad', 'zot6'])) {
        return $y;
    }

    if(! $y) {
        $y = import_author_activitypub($x);
    }

    if(! $y) {
        $y = import_author_unknown($x);
    }

    return($y);
}


function import_author_activitypub($x) {

    if(! $x['url'])
        return false;

    // let somebody upgrade from an 'unknown' connection which has no xchan_addr and resolve issues with identities from multiple protocols using the same url

    $r = q("select xchan_hash, xchan_url, xchan_network, xchan_name, xchan_photo_s from xchan left join hubloc on xchan_hash = hubloc_hash where hubloc_id_url = '%s' and hubloc_deleted = 0",
        dbesc($x['url'])
    );
    if(! $r) {
        $r = q("select xchan_hash, xchan_url, xchan_network, xchan_name, xchan_photo_s from xchan where xchan_hash = '%s' ",
            dbesc($x['url'])
        );
    }
    if($r) {
        $ptr = null;
        foreach($r as $rv) {
            if (str_contains($rv['xchan_network'], 'zot') || str_contains($rv['xchan_network'], 'nomad')) {
                $ptr = $rv;
            }
        }
        if(! $ptr) {
            $ptr = $r[0];
        }

        logger('in_cache: ' . $ptr['xchan_name'], LOGGER_DATA);
        return $ptr['xchan_hash'];
    }

    $z = discover_resource($x['url']);

    if($z) {
        $r = q("select xchan_hash, xchan_url, xchan_network, xchan_name, xchan_photo_s from xchan left join hubloc on xchan_hash = hubloc_hash where hubloc_id_url = '%s' and hubloc_deleted = 0",
            dbesc($x['url'])
        );
        if(! $r) {
            $r = q("select xchan_hash, xchan_url, xchan_name, xchan_photo_s from xchan where xchan_hash = '%s' ",
                dbesc($x['url'])
            );
        }
        if($r) {
            foreach($r as $rv) {
                if (str_contains($rv['xchan_network'], 'zot')) {
                    return $rv['xchan_hash'];
                }
            }
            return $r[0]['xchan_hash'];
        }
    }

    return false;
}


function import_author_unknown($x) {

    $arr = [
            'author' => $x,
            'result' => false
    ];
    /**
     * @hooks import_author
     *   * \e array \b author
     *   * \e boolean|string \b result - Return value, default false
     */
    Hook::call('import_author', $arr);
    if($arr['result'])
        return $arr['result'];

    if(! $x['url'])
        return false;

    $r = q("select xchan_hash from xchan where xchan_network = 'unknown' and xchan_url = '%s' limit 1",
        dbesc($x['url'])
    );
    if($r) {
        logger('In cache' , LOGGER_DEBUG);
        return $r[0]['xchan_hash'];
    }

    $name = trim($x['name']);

    $r = xchan_store_lowlevel(
        [
            'xchan_hash'         => $x['url'],
            'xchan_guid'         => $x['url'],
            'xchan_url'          => $x['url'],
            'xchan_updated'      => datetime_convert(),
            'xchan_name'         => (($name) ?: t('(Unknown)')),
            'xchan_name_date'    => datetime_convert(),
            'xchan_network'      => 'unknown'
        ]
    );

    if($r && $x['photo']) {

        $photos = import_remote_xchan_photo($x['photo']['src'],$x['url']);

        if($photos) {
            $r = q("update xchan set xchan_updated = '%s', xchan_photo_date = '%s', xchan_photo_l = '%s', xchan_photo_m = '%s', xchan_photo_s = '%s', xchan_photo_mimetype = '%s' where xchan_hash = '%s' and xchan_network = 'unknown'",
                dbesc(datetime_convert()),
                dbesc(datetime_convert()),
                dbesc($photos[0]),
                dbesc($photos[1]),
                dbesc($photos[2]),
                dbesc($photos[3]),
                dbesc($x['url'])
            );
            if($r)
                return $x['url'];
        }
    }

    return false;
}

function empty_acl($item) {
    return $item['allow_cid'] === EMPTY_STR && $item['allow_gid'] === EMPTY_STR && $item['deny_cid'] === EMPTY_STR && $item['deny_gid'] === EMPTY_STR;
}

function encode_item($item,$mirror = false) {
    $x = [];
    $x['type'] = 'activity';
    $x['encoding'] = 'zot';

    // If we're trying to back up an item so that it's recoverable or for export/imprt,
    // add all the attributes we need to recover it

    if($mirror) {
        $x['id'] = $item['id'];
        $x['parent'] = $item['parent'];
        $x['uid'] = $item['uid'];
        $x['allow_cid'] = $item['allow_cid'];
        $x['allow_gid'] = $item['allow_gid'];
        $x['deny_cid'] = $item['deny_cid'];
        $x['deny_gid'] = $item['deny_gid'];
        $x['revision'] = $item['revision'];
        $x['layout_mid'] = $item['layout_mid'];
        $x['postopts'] = $item['postopts'];
        $x['resource_id'] = $item['resource_id'];
        $x['resource_type'] = $item['resource_type'];
        $x['attach'] = $item['attach'];
        $x['item_origin'] = $item['item_origin'];
        $x['item_unseen'] = $item['item_unseen'];
        $x['item_starred'] = $item['item_starred'];
        $x['item_uplink'] = $item['item_uplink'];
        $x['item_consensus'] = $item['item_consensus'];
        $x['item_wall'] = $item['item_wall'];
        $x['item_thread_top'] = $item['item_thread_top'];
        $x['item_notshown'] = $item['item_notshown'];
        $x['item_nsfw'] = $item['item_nsfw'];
        $x['item_relay'] = $item['item_relay'];
        $x['item_mentionsme'] = $item['item_mentionsme'];
        $x['item_nocomment'] = $item['item_nocomment'];
        $x['item_obscured'] = $item['item_obscured'];
        $x['item_verified'] = $item['item_verified'];
        $x['item_retained'] = $item['item_retained'];
        $x['item_rss'] = $item['item_rss'];
        $x['item_deleted'] = $item['item_deleted'];
        $x['item_type'] = $item['item_type'];
        $x['item_hidden'] = $item['item_hidden'];
        $x['item_unpublished'] = $item['item_unpublished'];
        $x['item_delayed'] = $item['item_delayed'];
        $x['item_pending_remove'] = $item['item_pending_remove'];
        $x['item_blocked'] = $item['item_blocked'];
    }

    $x['uuid']            = $item['uuid'];
    $x['message_id']      = $item['mid'];
    $x['approved']        = $item['approved'];
    $x['message_top']     = $item['parent_mid'];
    $x['message_parent']  = $item['thr_parent'];
    $x['created']         = $item['created'];
    $x['edited']          = $item['edited'];
    // always send 0's over the wire
    $x['expires']         = (($item['expires'] === '0001-01-01 00:00:00') ? '0000-00-00 00:00:00' : $item['expires']);
    $x['commented']       = $item['commented'];
    $x['mimetype']        = $item['mimetype'];
    $x['title']           = $item['title'];
    $x['summary']         = $item['summary'];
    $x['body']            = $item['body'];
    $x['app']             = $item['app'];
    $x['verb']            = $item['verb'];
    $x['object_type']     = $item['obj_type'];
    $x['target_type']     = $item['tgt_type'];
    $x['permalink']       = $item['plink'];
    $x['location']        = $item['location'];
    $x['longlat']         = ($item['lat'] || $item['lon']) ? $item['lat'] . ' ' . $item['lon'] : 0.0;
    $x['signature']       = $item['sig'];
    $x['replyto']         = $item['replyto'];
    $x['owner']           = encode_item_xchan($item['owner']);
    $x['author']          = encode_item_xchan($item['author']);

    if($item['obj'])
        $x['object']      = json_decode($item['obj'],true);
    if($item['target'])
        $x['target']      = json_decode($item['target'],true);
    if($item['attach'])
        $x['attach']      = json_decode($item['attach'],true);
    if($y = encode_item_flags($item))
        $x['flags']       = $y;

    if($item['comments_closed'] > NULL_DATE) {
        $x['comments_closed'] = $item['comments_closed'];
    }

    $x['comment_scope'] = $item['comment_policy'];

    if($item['term'])
        $x['tags']        = encode_item_terms($item['term'],$mirror);

    if($item['iconfig'])
        $x['meta']        = encode_item_meta($item['iconfig'],$mirror);


    logger('encode_item: ' . print_r($x,true), LOGGER_DATA);

    return $x;
}

/**
 * @brief
 *
 * @param int $scope
 * @param boolean $strip (optional) default false
 * @return string
 */
function map_scope($scope, $strip = false) {
    switch($scope) {
        case 0:
            return 'self';
        case PERMS_PUBLIC:
            if($strip)
                return '';
            return 'public';
        case PERMS_NETWORK:
            return 'network: red';
        case PERMS_AUTHED:
            return 'authenticated';
        case PERMS_SITE:
            return 'site: ' . App::get_hostname();
        case PERMS_PENDING:
            return 'any connections';
        case PERMS_SPECIFIC:
            return 'specific';
        case PERMS_CONTACTS:
        default:
            return 'contacts';
    }
}

/**
 * @brief Returns a descriptive text for a given $scope.
 *
 * @param string $scope
 * @return string translated string describing the scope
 */
function translate_scope($scope) {
    if(! $scope || $scope === 'public')
        return t('Visible to anybody on the internet.');
    if(str_starts_with($scope, 'self'))
        return t('Visible to you only.');
    if(str_starts_with($scope, 'network:'))
        return t('Visible to anybody in this network.');
    if(str_starts_with($scope, 'authenticated'))
        return t('Visible to anybody authenticated.');
    if(str_starts_with($scope, 'site:'))
        return sprintf( t('Visible to anybody on %s.'), strip_tags(substr($scope,6)));
    if(str_starts_with($scope, 'any connections'))
        return t('Visible to all connections.');
    if(str_starts_with($scope, 'contacts'))
        return t('Visible to approved connections.');
    if(str_starts_with($scope, 'specific'))
        return t('Visible to specific connections.');
    return ''; // This shouldn't happen.
}

/**
 * @brief
 *
 * @param array $xchan
 * @return array an associative array
 */
function encode_item_xchan($xchan) {
    $ret = [];

    $ret['name']     = $xchan['xchan_name'];
    $ret['address']  = $xchan['xchan_addr'];
    $ret['url']      = $xchan['xchan_url'];
    $ret['network']  = $xchan['xchan_network'];
    $ret['photo']    = [
        'mimetype' => $xchan['xchan_photo_mimetype'],
        'src' => $xchan['xchan_photo_m']
    ];
    $ret['id']       = $xchan['xchan_guid'];
    $ret['id_sig']   = $xchan['xchan_guid_sig'];
    $ret['key']      = $xchan['xchan_pubkey'];

    return $ret;
}

function encode_item_terms($terms,$mirror = false) {
    $ret = [];

    $allowed_export_terms = [TERM_UNKNOWN, TERM_HASHTAG, TERM_MENTION, TERM_CATEGORY, TERM_BOOKMARK, TERM_COMMUNITYTAG, TERM_FORUM];

    if($mirror) {
        $allowed_export_terms[] = TERM_PCATEGORY;
        $allowed_export_terms[] = TERM_FILE;
    }

    if($terms) {
        foreach($terms as $term) {
            if(in_array($term['ttype'],$allowed_export_terms))
                $ret[] = ['tag' => $term['term'], 'url' => $term['url'], 'type' => termtype($term['ttype'])];
        }
    }

    return $ret;
}

function encode_item_meta($meta,$mirror = false) {
    $ret = [];

    if($meta) {
        foreach($meta as $m) {
            if($m['sharing'] || $mirror)
                $ret[] = ['family' => $m['cat'], 'key' => $m['k'], 'value' => $m['v'], 'sharing' => intval($m['sharing'])];
        }
    }

    return $ret;
}

function decode_item_meta($meta) {
    $ret = [];

    if(is_array($meta) && $meta) {
        foreach($meta as $m) {
            $ret[] = ['cat' => escape_tags($m['family']),'k' => escape_tags($m['key']),'v' => $m['value'],'sharing' => $m['sharing']];
        }
    }
    return $ret;
}

/**
 * @brief
 *
 * @param int $t
 * @return string
 */
function termtype($t) {
    $types = ['unknown', 'hashtag', 'mention', 'category', 'personal_category', 'file',
        'search', 'thing', 'bookmark', 'hierarchy', 'communitytag', 'forum'];

    return(($types[$t]) ?: 'unknown');
}

/**
 * @brief
 *
 * @param array $t
 * @return array|string empty string or array containing associative arrays with
 *   * \e string \b term
 *   * \e string \b url
 *   * \e int \b type
 */
function decode_tags($t) {
    if($t) {
        $ret = [];
        foreach($t as $x) {
            $tag = [];
            $tag['term'] = htmlspecialchars($x['tag'], ENT_COMPAT, 'UTF-8', false);
            $tag['url']  = htmlspecialchars($x['url'], ENT_COMPAT, 'UTF-8', false);
            switch($x['type']) {
                case 'hashtag':
                    $tag['ttype'] = TERM_HASHTAG;
                    break;
                case 'mention':
                    $tag['ttype'] = TERM_MENTION;
                    break;
                case 'category':
                    $tag['ttype'] = TERM_CATEGORY;
                    break;
                case 'personal_category':
                    $tag['ttype'] = TERM_PCATEGORY;
                    break;
                case 'file':
                    $tag['ttype'] = TERM_FILE;
                    break;
                case 'search':
                    $tag['ttype'] = TERM_SAVEDSEARCH;
                    break;
                case 'thing':
                    $tag['ttype'] = TERM_THING;
                    break;
                case 'bookmark':
                    $tag['ttype'] = TERM_BOOKMARK;
                    break;
                case 'communitytag':
                    $tag['ttype'] = TERM_COMMUNITYTAG;
                    break;
                case 'forum':
                    $tag['ttype'] = TERM_FORUM;
                    break;
                default:
                case 'unknown':
                    $tag['ttype'] = TERM_UNKNOWN;
                    break;
            }
            $ret[] = $tag;
        }

        return $ret;
    }

    return '';
}


function purify_imported_object($obj) {
    $ret = null;
    if (is_array($obj)) {
        foreach ( $obj as $k => $v ) {
            if (is_array($v)) {
                $ret[$k] = purify_imported_object($v);
            }
            elseif (is_string($v)) {
                $ret[$k] = purify_html($v);
            }
        }
    }
    elseif (is_string($obj)) {
        $ret = purify_html($obj);
    }

    return $ret;
}


/**
 * @brief Sanitise a potentially complex array.
 *
 * Walks the array and applies htmlspecialchars to the content unless it is a known HTML element,
 * in which case the result is purified
 *
 * @param array $arr
 * @return array|string
 */

function activity_sanitise($arr) {
    if($arr) {
        if(is_array($arr)) {
            $ret = [];
            foreach($arr as $k => $x) {
                if ($k === 'source' && array_path_exists('source/mediaType',$arr)) {
                    if (array_path_exists('source/content',$arr) && isset($arr['source']['mediaType']) && in_array($arr['source']['mediaType'], [ 'text/bbcode', 'text/x-multicode' ])) {
                        // @FIXME multicode
                        $ret[$k] = [ 'mediaType' => 'text/x-multicode' ];
                        if (is_string($arr['source']['content'])) {
                            $ret[$k]['content'] = multicode_purify($arr['source']['content']);
                        }
                        if (array_path_exists('source/summary',$arr) && is_string($arr['source']['summary'])) {
                            $ret[$k]['summary'] = multicode_purify($arr['source']['summary']);
                        }
                        continue;
                    }
                }
                if (in_array($k, [ 'content', 'summary', 'contentMap', 'summaryMap' ])) {
                    $ret[$k] = purify_imported_object($x);
                    continue;
                }
                if(is_array($x))
                    $ret[$k] = activity_sanitise($x);
                else
                    $ret[$k] = htmlspecialchars((isset($x) ? $x : ''), ENT_COMPAT, 'UTF-8', false);
            }
            return $ret;
        }
        else {
            return htmlspecialchars($arr, ENT_COMPAT, 'UTF-8', false);
        }
    }

    return '';
}

/**
 * @brief Sanitise a simple linear array.
 *
 * @param array $arr
 * @return array|string
 */
function array_sanitise($arr) {
    if($arr) {
        $ret = [];
        foreach($arr as $x) {
            $ret[] = htmlspecialchars($x, ENT_COMPAT,'UTF-8',false);
        }
        return $ret;
    }

    return '';
}

function encode_item_flags($item) {

//    most of item_flags and item_restrict are local settings which don't apply when transmitted.
//  We may need those for the case of syncing other hub locations which you are attached to.

    $ret = [];

    if(intval($item['item_deleted']))
        $ret[] = 'deleted';
    if(intval($item['item_hidden']))
        $ret[] = 'hidden';
    if(intval($item['item_notshown']))
        $ret[] = 'notshown';
    if(intval($item['item_thread_top']))
        $ret[] = 'thread_parent';
    if(intval($item['item_nsfw']))
        $ret[] = 'nsfw';
    if(intval($item['item_consensus']))
        $ret[] = 'consensus';
    if(intval($item['item_obscured']))
        $ret[] = 'obscured';
    if(intval($item['item_private']))
        $ret[] = 'private';
    if(intval($item['item_private']) === 2)
        $ret[] = 'direct';

    return $ret;
}

// Superceded by Libzotdir::import_directory_profile
// This is probably no longer needed.

function get_profile_elements($profile) {

    $arr = [];

    $xchan_hash = import_author_xchan($profile['from']);
    if($xchan_hash) {
        $arr['xprof_hash'] = $xchan_hash;
    }
    else {
        return [];
    }

    $arr['desc']         = (($profile['title']) ? htmlspecialchars($profile['title'],ENT_COMPAT,'UTF-8',false) : '');

    $arr['dob']          = datetime_convert('UTC','UTC',$profile['birthday'],'Y-m-d');
    $arr['age']          = (($profile['age']) ? intval($profile['age']) : 0);

    $arr['gender']       = (($profile['gender'])    ? htmlspecialchars($profile['gender'],    ENT_COMPAT,'UTF-8',false) : '');
    $arr['marital']      = (($profile['marital'])   ? htmlspecialchars($profile['marital'],   ENT_COMPAT,'UTF-8',false) : '');
    $arr['sexual']       = (($profile['sexual'])    ? htmlspecialchars($profile['sexual'],    ENT_COMPAT,'UTF-8',false) : '');
    $arr['locale']       = (($profile['locale'])    ? htmlspecialchars($profile['locale'],    ENT_COMPAT,'UTF-8',false) : '');
    $arr['region']       = (($profile['region'])    ? htmlspecialchars($profile['region'],    ENT_COMPAT,'UTF-8',false) : '');
    $arr['postcode']     = (($profile['postcode'])  ? htmlspecialchars($profile['postcode'],  ENT_COMPAT,'UTF-8',false) : '');
    $arr['country']      = (($profile['country'])   ? htmlspecialchars($profile['country'],   ENT_COMPAT,'UTF-8',false) : '');

    $arr['keywords']     = (($profile['keywords'] && is_array($profile['keywords'])) ? array_sanitise($profile['keywords']) : []);

    return $arr;
}


/**
 * @brief Signs an item body.
 *
 * @param[in,out] array $item
 */
function item_sign(&$item) {

    if(array_key_exists('sig',$item) && $item['sig'])
        return;

    $r = q("select channel_prvkey from channel where channel_id = %d and channel_hash = '%s' ",
            intval($item['uid']),
            dbesc($item['author_xchan'])
    );
    if(! $r)
        return;

    $item['sig'] = Libzot::sign($item['body'], $r[0]['channel_prvkey']);
    $item['item_verified'] = 1;
}

// packs  json data for storage.
// if it is a string, check if it is already json encoded.
// Otherwise, json encode it
// If it is an array, sanitise it and  then json_encode it.


function item_json_encapsulate($arr,$k)  {
    $retval = null;

    if (isset($arr[$k])) {
        if (is_string($arr[$k])) {
            // determine if it is json encoded already
            $test = json_decode($arr[$k]);
            // assume it is json encoded already
            $retval = $arr[$k];
            if ($test === NULL) {
                $retval = json_encode($arr[$k], JSON_UNESCAPED_SLASHES);
            }
        }
        else {
            activity_sanitise($arr[$k]);
            $retval = json_encode($arr[$k], JSON_UNESCAPED_SLASHES);
        }
    }

    return $retval;
}

/**
 * @brief Stores an item type record.
 *
 * @param array $arr
 * @param boolean $deliver (optional) default true
 *
 * @return array
 *   * \e boolean \b success
 *   * \e int \b item_id
 */
function item_store($arr, $deliver = true) {

    $d = [
            'item' => $arr,
    ];
    /**
     * @hooks item_store_before
     *   Called when item_store() stores a record of type item.
     *   * \e array \b item
     */
    Hook::call('item_store_before', $d);
    $arr = $d['item'];

    $ret = ['success' => false, 'item_id' => 0];

    if(array_key_exists('cancel',$arr) && $arr['cancel']) {
        logger('cancelled by plugin');
        return $ret;
    }

    if(! $arr['uid']) {
        logger('item_store: no uid');
        $ret['message'] = 'No uid.';
        return $ret;
    }

    //$uplinked_comment = false;

    // If a page layout is provided, ensure it exists and belongs to us.

    if(array_key_exists('layout_mid',$arr) && $arr['layout_mid']) {
        $l = q("select item_type from item where mid = '%s' and uid = %d limit 1",
            dbesc($arr['layout_mid']),
            intval($arr['uid'])
        );
        if((! $l) || ($l[0]['item_type'] != ITEM_TYPE_PDL))
            unset($arr['layout_mid']);
    }

    // Don't let anybody set these, either intentionally or accidentally

    if(array_key_exists('id',$arr))
        unset($arr['id']);
    if(array_key_exists('parent',$arr))
        unset($arr['parent']);

    $arr['mimetype']      = ((x($arr,'mimetype'))      ? notags(trim($arr['mimetype']))      : 'text/x-multicode');

    $arr['title']   = ((array_key_exists('title',$arr)   && strlen($arr['title']))    ? trim(escape_tags($arr['title']))   : '');
    $arr['summary'] = ((array_key_exists('summary',$arr) && strlen($arr['summary']))  ? trim($arr['summary']) : '');
    $arr['body']    = ((array_key_exists('body',$arr)    && strlen($arr['body']))     ? trim($arr['body'])    : '');

    $arr['allow_cid']     = ((x($arr,'allow_cid'))     ? trim($arr['allow_cid'])             : '');
    $arr['allow_gid']     = ((x($arr,'allow_gid'))     ? trim($arr['allow_gid'])             : '');
    $arr['deny_cid']      = ((x($arr,'deny_cid'))      ? trim($arr['deny_cid'])              : '');
    $arr['deny_gid']      = ((x($arr,'deny_gid'))      ? trim($arr['deny_gid'])              : '');
    $arr['postopts']      = ((x($arr,'postopts'))      ? trim($arr['postopts'])              : '');
    $arr['uuid']          = ((x($arr,'uuid'))          ? trim($arr['uuid'])                  : '');
    $arr['approved']      = ((x($arr,'approved'))      ? trim($arr['approved'])              : '');
    $arr['item_private']  = ((x($arr,'item_private'))  ? intval($arr['item_private'])        : 0 );
    $arr['item_wall']     = ((x($arr,'item_wall'))     ? intval($arr['item_wall'])           : 0 );
    $arr['item_type']     = ((x($arr,'item_type'))     ? intval($arr['item_type'])           : 0 );
    $arr['item_verified'] = ((x($arr,'item_verified')) ? intval($arr['item_verified'])       : 0 );

    // obsolete, but needed so as not to throw not-null constraints on some database driveres
    $arr['item_flags']    = ((x($arr,'item_flags'))    ? intval($arr['item_flags'])          : 0 );

    $languagetext = prepare_text($arr['body'],((isset($arr['mimetype'])) ? $arr['mimetype'] : 'text/x-multicode'));
    $languagetext = html2plain((isset($arr['title']) && $arr['title']) ? $arr['title'] . ' ' . $languagetext : $languagetext);

    $detector = new LanguageDetect();
    $arr['lang'] = $detector->detect($languagetext);

    // apply the input filter here

    $arr['summary'] = trim(z_input_filter($arr['summary'],$arr['mimetype']));
    $arr['body'] = trim(z_input_filter($arr['body'],$arr['mimetype']));

    item_sign($arr);

    if(! array_key_exists('sig',$arr))
        $arr['sig'] = '';

    $allowed_languages = get_pconfig($arr['uid'],'system','allowed_languages');

    if((is_array($allowed_languages)) && ($arr['lang']) && (! array_key_exists($arr['lang'],$allowed_languages))) {
        $translate = [
                'item' => $arr,
                'from' => $arr['lang'],
                'to' => $allowed_languages,
                'translated' => false
        ];
        /**
         * @hooks item_translate
         *   Called from item_store and item_store_update after the post language has been autodetected.
         *   * \e array \b item
         *   * \e string \b from
         *   * \e string \b to
         *   * \e boolean \b translated
         */
        Hook::call('item_translate', $translate);
        if((! $translate['translated']) && (intval(get_pconfig($arr['uid'],'system','reject_disallowed_languages')))) {
            logger('language ' . $arr['lang'] . ' not accepted for uid ' . $arr['uid']);
            $ret['message'] = 'language not accepted';
            return $ret;
        }
        $arr = $translate['item'];
    }
    if(isset($arr['obj'])) {
        $arr['obj'] = item_json_encapsulate($arr,'obj');
    }

    if(isset($arr['target'])) {
        $arr['target'] = item_json_encapsulate($arr,'target');
    }

    if(isset($arr['attach'])) {
        $arr['attach'] = item_json_encapsulate($arr,'attach');
    }

    $arr['aid']           = ((x($arr,'aid'))           ? intval($arr['aid'])                           : 0);
    $arr['mid']           = ((x($arr,'mid'))           ? notags(trim($arr['mid']))                     : random_string());
    $arr['revision']      = ((x($arr,'revision') && intval($arr['revision']) > 0)   ? intval($arr['revision']) : 0);

    $arr['author_xchan']  = ((x($arr,'author_xchan'))  ? notags(trim($arr['author_xchan']))  : '');
    $arr['owner_xchan']   = ((x($arr,'owner_xchan'))   ? notags(trim($arr['owner_xchan']))   : '');
    $arr['created']       = ((x($arr,'created') !== false) ? datetime_convert('UTC','UTC',$arr['created']) : datetime_convert());
    $arr['edited']        = ((x($arr,'edited')  !== false) ? datetime_convert('UTC','UTC',$arr['edited'])  : datetime_convert());
    $arr['expires']       = ((x($arr,'expires')  !== false) ? datetime_convert('UTC','UTC',$arr['expires'])  : NULL_DATE);
    $arr['commented']     = ((x($arr,'commented')  !== false) ? datetime_convert('UTC','UTC',$arr['commented'])  : datetime_convert());
    $arr['comments_closed'] = ((x($arr,'comments_closed')  !== false) ? datetime_convert('UTC','UTC',$arr['comments_closed'])  : NULL_DATE);
    $arr['html'] = ((array_key_exists('html',$arr)) ? $arr['html'] : '');

    if($deliver) {
        $arr['received']      = datetime_convert();
        $arr['changed']       = datetime_convert();
    }
    else {

        // When deliver flag is false, we are *probably* performing an import or bulk migration.
        // If one updates the changed timestamp it will be made available to zotfeed and delivery
        // will still take place through backdoor methods. Since these fields are rarely used
        // otherwise, just preserve the original timestamp.

        $arr['received']      = ((x($arr,'received')  !== false) ? datetime_convert('UTC','UTC',$arr['received'])  : datetime_convert());
        $arr['changed']       = ((x($arr,'changed')  !== false) ? datetime_convert('UTC','UTC',$arr['changed'])  : datetime_convert());
    }

    $arr['location']      = ((x($arr,'location'))      ? notags(trim($arr['location']))      : '');
    $arr['lat']           = ((x($arr, 'lat'))          ? floatval($arr['lat'])               : 0.0);
    $arr['lon']           = ((x($arr, 'lon'))          ? floatval($arr['lon'])               : 0.0);
    $arr['parent_mid']    = ((x($arr,'parent_mid'))    ? notags(trim($arr['parent_mid']))    : '');
    $arr['thr_parent']    = ((x($arr,'thr_parent'))    ? notags(trim($arr['thr_parent']))    : $arr['parent_mid']);
    $arr['verb']          = ((x($arr,'verb'))          ? notags(trim($arr['verb']))          : ACTIVITY_POST);
    $arr['obj_type']      = ((x($arr,'obj_type'))      ? notags(trim($arr['obj_type']))      : ACTIVITY_OBJ_NOTE);
    $arr['obj']           = ((x($arr,'obj'))           ? trim($arr['obj'])                   : '');
    $arr['tgt_type']      = ((x($arr,'tgt_type'))      ? notags(trim($arr['tgt_type']))      : '');
    $arr['target']        = ((x($arr,'target'))        ? trim($arr['target'])                : '');
    $arr['plink']         = ((x($arr,'plink'))         ? notags(trim($arr['plink']))         : '');
    $arr['attach']        = ((x($arr,'attach'))        ? notags(trim($arr['attach']))        : '');
    $arr['app']           = ((x($arr,'app'))           ? notags(trim($arr['app']))           : '');
    $arr['replyto']       = ((x($arr,'replyto'))       ? serialise($arr['replyto'])          : '');

    // No longer used but needs to be set to something or the database will complain.
    $arr['route'] = '';

    $arr['public_policy'] = '';

    $arr['comment_policy'] = ((x($arr,'comment_policy')) ? notags(trim($arr['comment_policy']))  : 'contacts' );

    $arr['item_unseen'] = ((array_key_exists('item_unseen',$arr)) ? intval($arr['item_unseen']) : 1 );
    $arr['item_restrict'] = ((array_key_exists('item_restrict',$arr)) ? intval($arr['item_restrict']) : 0 );

    if((! array_key_exists('item_nocomment',$arr)) && ($arr['comment_policy'] == 'none'))
        $arr['item_nocomment'] = 1;

    // handle time travelers
    // Allow a bit of fudge in case somebody just has a slightly slow/fast clock

    $d1 = new DateTime('now +10 minutes', new DateTimeZone('UTC'));
    $d2 = new DateTime($arr['created'] . '+00:00');
    if($d2 > $d1)
        $arr['item_delayed'] = 1;

    $arr['llink'] = z_root() . '/display/?mid=' . gen_link_id($arr['mid']);

    if (! $arr['plink']) {
        $arr['plink'] = $arr['llink'];
    }
    if($arr['parent_mid'] === $arr['mid']) {
        $parent_id = 0;
        $parent_deleted = 0;
        $allow_cid = $arr['allow_cid'];
        $allow_gid = $arr['allow_gid'];
        $deny_cid  = $arr['deny_cid'];
        $deny_gid  = $arr['deny_gid'];
        $comments_closed = $arr['comments_closed'];
        $arr['item_thread_top'] = 1;
        $arr['item_level'] = 0;
    }
    else {

        // find the parent and snarf the item id and ACL's
        // and anything else we need to inherit

        $r = q("SELECT item_level FROM item WHERE (mid = '%s' OR mid = '%s') AND uid = %d ORDER BY id ASC LIMIT 1",
            dbesc($arr['thr_parent']),
            dbesc(reverse_activity_mid($arr['thr_parent'])),
            intval($arr['uid'])
        );
        if($r) {
            $arr['item_level'] = intval($r[0]['item_level']) + 1;
        }
        else {
            $arr['item_level'] = 1;
        }

        $r = q("SELECT * FROM item WHERE (mid = '%s' OR mid = '%s') AND uid = %d ORDER BY id ASC LIMIT 1",
            dbesc($arr['parent_mid']),
            dbesc(reverse_activity_mid($arr['parent_mid'])),
            intval($arr['uid'])
        );

        // We may have this parent_mid without a token, so try that if we find a token

        if (! $r) {
            if (strpos($arr['parent_mid'],'token=')) {
                $r = q("SELECT * FROM item WHERE mid = '%s' AND uid = %d ORDER BY id ASC LIMIT 1",
                    dbesc(substr($arr['parent_mid'],0,strpos($arr['parent_mid'],'?'))),
                    intval($arr['uid'])
                );
                if ($r) {
                    $arr['parent_mid'] = $arr['thr_parent'] = substr($arr['parent_mid'],0,strpos($arr['parent_mid'],'?'));
                }
            }
        }

        if ($r) {

            $parent_item = array_shift($r);

            // in case item_store was killed before the parent's parent attribute got set,
            // set it now. This happens with some regularity on Dreamhost. This will keep
            // us from getting notifications for threads that exist but which we can't see.

            if(($parent_item['mid'] === $parent_item['parent_mid']) && (! intval($parent_item['parent']))) {
                q("update item set parent = id where id = %d",
                    intval($parent_item['id'])
                );
            }

            if(comments_are_now_closed($parent_item)) {
                logger('item_store: comments closed');
                $ret['message'] = 'Comments closed.';
                return $ret;
            }

            if(($arr['obj_type'] == ACTIVITY_OBJ_NOTE) && (! $arr['obj']))
                $arr['obj_type'] = ACTIVITY_OBJ_COMMENT;

            // is the new message multi-level threaded?
            // even though we don't support it now, preserve the info
            // and re-attach to the conversation parent.

            if($parent_item['mid'] != $parent_item['parent_mid']) {
                $arr['parent_mid'] = $parent_item['parent_mid'];
                $z = q("SELECT * FROM item WHERE mid = '%s' AND parent_mid = '%s' AND uid = %d
                    ORDER BY id ASC LIMIT 1",
                    dbesc($parent_item['parent_mid']),
                    dbesc($parent_item['parent_mid']),
                    intval($arr['uid'])
                );
                if($z && count($z))
                    $r = $z;
            }

            $parent_id       = $parent_item['id'];
            $parent_deleted  = $parent_item['item_deleted'];

            // item_restrict indicates an activitypub reply with a different
            // delivery algorithm than the "parent-relay" or inherited privacy mode

            if(! (intval($arr['item_restrict']) & 1)) {
                $allow_cid       = $parent_item['allow_cid'];
                $allow_gid       = $parent_item['allow_gid'];
                $deny_cid        = $parent_item['deny_cid'];
                $deny_gid        = $parent_item['deny_gid'];
            }

            $comments_closed = $parent_item['comments_closed'];

            if(intval($parent_item['item_wall']))
                $arr['item_wall'] = 1;

            // An uplinked comment might arrive with a downstream owner.
            // Fix it.

            if($parent_item['owner_xchan'] !== $arr['owner_xchan']) {
                $arr['owner_xchan'] = $parent_item['owner_xchan'];
                //                $uplinked_comment = true;
            }

            // if the parent is private and the child is not, force privacy for the entire conversation
            // if the child is private, leave it alone regardless of the parent privacy state

            if(intval($parent_item['item_private']) && (! intval($arr['item_private']))) {
                $arr['item_private'] = $parent_item['item_private'];
            }

            // Edge case. We host a public forum that was originally posted privately.
            // The original author commented, but as this is a comment, the permissions
            // weren't fixed up and will still show the comment as private unless we fix it here.

            if(intval($parent_item['item_uplink']) && (! $parent_item['item_private']))
                $arr['item_private'] = 0;

            if(in_array($arr['obj_type'], ['Note','Answer']) && $parent_item['obj_type'] === 'Question' && intval($parent_item['item_wall'])) {
                Activity::update_poll($parent_item, $arr);
            }
        }
        else {
            logger('item_store: item parent was not found - ignoring item');
            $ret['message'] = 'parent not found.';
            return $ret;
        }
    }

    if($parent_deleted)
        $arr['item_deleted'] = 1;

    $r = q("SELECT id FROM item WHERE mid = '%s' AND uid = %d and revision = %d LIMIT 1",
        dbesc($arr['mid']),
        intval($arr['uid']),
        intval($arr['revision'])
    );
    if($r) {
        logger('duplicate item ignored. ' . print_r($arr,true));
        $ret['message'] = 'duplicate post.';
        return $ret;
    }

    if (LibBlock::fetch_by_entity($arr['uid'],$arr['owner_xchan']) || LibBlock::fetch_by_entity($arr['uid'],$arr['author_xchan'])) {
        logger('Post cancelled by block rule.');
        $ret['message'] = 'cancelled.';
        return $ret;
    }

    /**
     * @hooks item_store
     *   Called when item_store() stores a record of type item.
     */

    Hook::call('item_store', $arr);

    /**
     * @hooks post_remote
     *   Called when an activity arrives from another site.
     *   This hook remains for backward compatibility.
     */
    Hook::call('post_remote', $arr);

    if(x($arr, 'cancel')) {
        logger('Post cancelled by plugin.');
        $ret['message'] = 'cancelled.';
        return $ret;
    }

    // pull out all the taxonomy stuff for separate storage

    $terms = null;
    if(array_key_exists('term',$arr)) {
        $terms = $arr['term'];
        unset($arr['term']);
    }

    $meta = null;
    if(array_key_exists('iconfig',$arr)) {
        $meta = $arr['iconfig'];
        unset($arr['iconfig']);
    }


    $private = intval($arr['item_private']);

    if (! $private) {
         if (strlen($allow_cid) || strlen($allow_gid) || strlen($deny_cid) || strlen($deny_gid)) {
            $private = 1;
        }
    }

    $arr['parent']          = $parent_id;
    $arr['allow_cid']       = $allow_cid;
    $arr['allow_gid']       = $allow_gid;
    $arr['deny_cid']        = $deny_cid;
    $arr['deny_gid']        = $deny_gid;
    $arr['item_private']    = $private;
    $arr['comments_closed'] = $comments_closed;

    logger('item_store: ' . print_r($arr,true), LOGGER_DATA);
    logger('item_store_terms: ' . print_r($terms, true), LOGGER_DATA);
    create_table_from_array('item',$arr);

    // find the item we just created

    $r = q("SELECT * FROM item WHERE mid = '%s' AND uid = %d and revision = %d ORDER BY id ASC ",
        dbesc($arr['mid']),
        intval($arr['uid']),
        intval($arr['revision'])
    );

    if($r) {
        // This will give us a fresh copy of what's now in the DB and undo the db escaping,
        // which really messes up the notifications

        $current_post = $r[0]['id'];
        $arr = $r[0];
        logger('item_store: created item ' . $current_post, LOGGER_DEBUG);
    }
    else {
        logger('item_store: could not locate stored item');
        $ret['message'] = 'unable to retrieve.';
        return $ret;
    }
    if(count($r) > 1) {
        logger('item_store: duplicated post occurred. Removing duplicates.');
        q("DELETE FROM item WHERE mid = '%s' AND uid = %d AND id != %d ",
            $arr['mid'],
            intval($arr['uid']),
            intval($current_post)
        );
    }

    $arr['id'] = $current_post;

    if(! intval($r[0]['parent'])) {
        q("update item set parent = id where id = %d",
            intval($r[0]['id'])
        );
        $arr['parent'] = $r[0]['id'];
    }


    // Store taxonomy

    if(($terms) && (is_array($terms))) {
        foreach($terms as $t) {
            q("insert into term (uid,oid,otype,ttype,term,url)
                values(%d,%d,%d,%d,'%s','%s') ",
                intval($arr['uid']),
                intval($current_post),
                intval(TERM_OBJ_POST),
                intval($t['ttype']),
                dbesc($t['term']),
                dbesc($t['url'])
            );
        }

        $arr['term'] = $terms;
    }

    if($meta) {
        foreach($meta as $m) {
            set_iconfig($current_post,$m['cat'],$m['k'],$m['v'],$m['sharing']);
        }
        $arr['iconfig'] = $meta;
    }


    $ret['item'] = $arr;

    /**
     * @hooks post_remote_end
     *   Called after processing a remote post.
     */
    Hook::call('post_remote_end', $arr);

    item_update_parent_commented($arr);

    if((str_contains($arr['body'], '[embed]')) || (str_contains($arr['body'], '[/img]')) || (str_contains($arr['body'], '[/zmg]'))) {
        Run::Summon([ 'Cache_embeds', $current_post ]);
    }

    // If _creating_ a deleted item, don't propagate it further or send out notifications.
    // We need to store the item details just in case the delete came in before the original post,
    // so that we have an item in the DB that's marked deleted and won't store a fresh post
    // that isn't aware that we were already told to delete it.

    if(($deliver) && (! intval($arr['item_deleted']))) {
        send_status_notifications($arr);
        tag_deliver($arr['uid'],$current_post);
    }

    $ret['success'] = true;
    $ret['item_id'] = $current_post;

//    if($linkid) {
//        $li = [ $ret['item'] ];
//        xchan_query($li);
//        $sync_item = fetch_post_tags($li);
//        Libsync::build_link_packet($arr['uid'],[ 'item' => [ encode_item($sync_item[0],true) ] ]);
//    }

    return $ret;
}


/**
 * @brief Update a stored item.
 *
 * @param array $arr an item
 * @param boolean $deliver (optional) default true
 * @return array
 */
function item_store_update($arr, $deliver = true) {

    $d = [
            'item' => $arr,
    ];
    /**
     * @hooks item_store_update_before
     *   Called when item_store_update() is called to update a stored item. It
     *   overwrites the function's parameters $arr
     *   * \e array \b item
     */
    Hook::call('item_store_update_before', $d);
    $arr = $d['item'];

    $ret = ['success' => false, 'item_id' => 0];

    if(array_key_exists('cancel',$arr) && $arr['cancel']) {
        logger('cancelled by plugin');
        return $ret;
    }

    if(! intval($arr['uid'])) {
        logger('no uid');
        $ret['message'] = 'no uid.';
        return $ret;
    }
    if(! intval($arr['id'])) {
        logger('no id');
        $ret['message'] = 'no id.';
        return $ret;
    }

    $orig_post_id = $arr['id'];
    $uid = $arr['uid'];

    $orig = q("select * from item where id = %d and uid = %d limit 1",
        intval($orig_post_id),
        intval($uid)
    );
    if(! $orig) {
        logger('Original post not found: ' . $orig_post_id);
        $ret['message'] = 'no original';
        return $ret;
    }

    // override the unseen flag with the original

    $arr['item_unseen'] = $orig[0]['item_unseen'];

    $arr['title'] = ((array_key_exists('title',$arr) && strlen($arr['title']))  ? trim(escape_tags($arr['title'])) : '');
    $arr['body']  = ((array_key_exists('body',$arr) && strlen($arr['body']))    ? trim($arr['body'])  : '');
    $arr['html']  = ((array_key_exists('html',$arr) && strlen($arr['html']))    ? trim($arr['html'])  : '');


    if(array_key_exists('edit',$arr))
        unset($arr['edit']);

    $arr['mimetype']      = ((x($arr,'mimetype'))      ? notags(trim($arr['mimetype']))      : 'text/x-multicode');

    $languagetext = prepare_text($arr['body'],((isset($arr['mimetype'])) ? $arr['mimetype'] : 'text/x-multicode'));
    $languagetext = html2plain((isset($arr['title']) && $arr['title']) ? $arr['title'] . ' ' . $languagetext : $languagetext);

    $detector = new LanguageDetect();
    $arr['lang'] = $detector->detect($languagetext);

    // apply the input filter here

    $arr['summary'] = trim(z_input_filter($arr['summary'],$arr['mimetype']));
    $arr['body']    = trim(z_input_filter($arr['body'],$arr['mimetype']));

    item_sign($arr);

    $allowed_languages = get_pconfig($arr['uid'],'system','allowed_languages');

    if((is_array($allowed_languages)) && ($arr['lang']) && (! array_key_exists($arr['lang'],$allowed_languages))) {
        $translate = [
                'item' => $arr,
                'from' => $arr['lang'],
                'to' => $allowed_languages,
                'translated' => false
        ];
        /**
         * @hooks item_translate
         *   Called from item_store() and item_store_update() after the post language has been autodetected.
         *   * \e array \b item - returned value
         *   * \e string \b from
         *   * \e string \b to
         *   * \e boolean \b translated - default false, set true if hook translated it and provide it in item
         */
        Hook::call('item_translate', $translate);
        if((! $translate['translated']) && (intval(get_pconfig($arr['uid'],'system','reject_disallowed_languages')))) {
            logger('item_store: language ' . $arr['lang'] . ' not accepted for uid ' . $arr['uid']);
            $ret['message'] = 'language not accepted';
            return $ret;
        }
        $arr = $translate['item'];
    }


    if(isset($arr['obj'])) {
        $arr['obj'] = item_json_encapsulate($arr,'obj');
    }

    if(isset($arr['target'])) {
        $arr['target'] = item_json_encapsulate($arr,'target');
    }

    if(isset($arr['attach'])) {
        $arr['attach'] = item_json_encapsulate($arr,'attach');
    }

    unset($arr['id']);
    unset($arr['uid']);
    unset($arr['aid']);
    unset($arr['uuid']);
    unset($arr['mid']);
    unset($arr['parent']);
    unset($arr['parent_mid']);
    unset($arr['author_xchan']);
    unset($arr['owner_xchan']);
    unset($arr['source_xchan']);
    unset($arr['thr_parent']);
    unset($arr['llink']);

    if (intval($orig[0]['item_unpublished'])) {

        $arr['created']       = ((x($arr,'created')  !== false) ? datetime_convert('UTC','UTC',$arr['created'])  : datetime_convert());
        $arr['edited']        = $arr['created'];
        $arr['expires']       = ((x($arr,'expires')  !== false) ? datetime_convert('UTC','UTC',$arr['expires'])  : NULL_DATE);

        if(array_key_exists('comments_closed',$arr) && $arr['comments_closed'] > NULL_DATE)
            $arr['comments_closed'] = datetime_convert('UTC','UTC',$arr['comments_closed']);
        else
            $arr['comments_closed'] = NULL_DATE;

        $arr['commented']     = $arr['created'];

        $arr['received']      = $arr['created'];
        $arr['changed']       = $arr['created'];
    }

    else {
        unset($arr['created']);

        $arr['expires']       = ((x($arr,'expires')  !== false) ? datetime_convert('UTC','UTC',$arr['expires'])  : $orig[0]['expires']);


        if(array_key_exists('comments_closed',$arr) && $arr['comments_closed'] > NULL_DATE)
            $arr['comments_closed'] = datetime_convert('UTC','UTC',$arr['comments_closed']);
        else
            $arr['comments_closed'] = $orig[0]['comments_closed'];

        $arr['commented']     = $orig[0]['commented'];
        $arr['received']      = $orig[0]['received'];
        $arr['changed']       = $orig[0]['changed'];
    }

    $arr['edited']        = ((x($arr,'edited')  !== false) ? datetime_convert('UTC','UTC',$arr['edited'])  : datetime_convert());
    $arr['revision']      = ((x($arr,'revision') && $arr['revision'] > 0)   ? intval($arr['revision']) : 0);

    $arr['location']      = ((x($arr,'location'))      ? notags(trim($arr['location']))      : $orig[0]['location']);
    $arr['uuid']          = ((x($arr,'uuid'))          ? notags(trim($arr['uuid']))          : $orig[0]['uuid']);
    $arr['approved']      = ((x($arr,'approved'))      ? notags(trim($arr['approved']))      : '');
    $arr['lat']           = ((x($arr,'lat'))           ? floatval($arr['lat'])               : $orig[0]['lat']);
    $arr['lon']           = ((x($arr,'lon'))           ? floatval($arr['lon'])               : $orig[0]['lon']);
    $arr['verb']          = ((x($arr,'verb'))          ? notags(trim($arr['verb']))          : $orig[0]['verb']);
    $arr['obj_type']      = ((x($arr,'obj_type'))      ? notags(trim($arr['obj_type']))      : $orig[0]['obj_type']);
    $arr['obj']           = ((x($arr,'obj'))           ? trim($arr['obj'])                   : $orig[0]['obj']);
    $arr['tgt_type']      = ((x($arr,'tgt_type'))      ? notags(trim($arr['tgt_type']))      : $orig[0]['tgt_type']);
    $arr['target']        = ((x($arr,'target'))        ? trim($arr['target'])                : $orig[0]['target']);
    $arr['plink']         = ((x($arr,'plink'))         ? notags(trim($arr['plink']))         : $orig[0]['plink']);
    $arr['replyto']       = ((x($arr,'replyto'))       ? serialise($arr['replyto'])          : $orig[0]['replyto']);

    $arr['allow_cid']     = ((array_key_exists('allow_cid',$arr))  ? trim($arr['allow_cid']) : $orig[0]['allow_cid']);
    $arr['allow_gid']     = ((array_key_exists('allow_gid',$arr))  ? trim($arr['allow_gid']) : $orig[0]['allow_gid']);
    $arr['deny_cid']      = ((array_key_exists('deny_cid',$arr))   ? trim($arr['deny_cid'])  : $orig[0]['deny_cid']);
    $arr['deny_gid']      = ((array_key_exists('deny_gid',$arr))   ? trim($arr['deny_gid'])  : $orig[0]['deny_gid']);
    $arr['item_private']  = ((array_key_exists('item_private',$arr)) ? intval($arr['item_private']) : $orig[0]['item_private']);


    $arr['attach']        = ((array_key_exists('attach',$arr))        ? notags(trim($arr['attach']))        : $orig[0]['attach']);

    $arr['app']           = ((array_key_exists('app',$arr))           ? notags(trim($arr['app']))           : $orig[0]['app']);

    $arr['item_origin']    = ((array_key_exists('item_origin',$arr))    ? intval($arr['item_origin'])          : $orig[0]['item_origin'] );
    $arr['item_unseen']    = ((array_key_exists('item_unseen',$arr))    ? intval($arr['item_unseen'])          : $orig[0]['item_unseen'] );
    $arr['item_starred']    = ((array_key_exists('item_starred',$arr))    ? intval($arr['item_starred'])          : $orig[0]['item_starred'] );
    $arr['item_uplink']    = ((array_key_exists('item_uplink',$arr))    ? intval($arr['item_uplink'])          : $orig[0]['item_uplink'] );
    $arr['item_consensus']    = ((array_key_exists('item_consensus',$arr))    ? intval($arr['item_consensus'])          : $orig[0]['item_consensus'] );
    $arr['item_wall']    = ((array_key_exists('item_wall',$arr))    ? intval($arr['item_wall'])          : $orig[0]['item_wall'] );
    $arr['item_thread_top']    = ((array_key_exists('item_thread_top',$arr))    ? intval($arr['item_thread_top'])          : $orig[0]['item_thread_top'] );
    $arr['item_notshown']    = ((array_key_exists('item_notshown',$arr))    ? intval($arr['item_notshown'])          : $orig[0]['item_notshown'] );
    $arr['item_nsfw']    = ((array_key_exists('item_nsfw',$arr))    ? intval($arr['item_nsfw'])          : $orig[0]['item_nsfw'] );
    $arr['item_relay']    = ((array_key_exists('item_relay',$arr))    ? intval($arr['item_relay'])          : $orig[0]['item_relay'] );
    $arr['item_mentionsme']    = ((array_key_exists('item_mentionsme',$arr))    ? intval($arr['item_mentionsme'])          : $orig[0]['item_mentionsme'] );
    $arr['item_nocomment']    = ((array_key_exists('item_nocomment',$arr))    ? intval($arr['item_nocomment'])          : $orig[0]['item_nocomment'] );
    $arr['item_obscured']    = ((array_key_exists('item_obscured',$arr))    ? intval($arr['item_obscured'])          : $orig[0]['item_obscured'] );
    $arr['item_verified']    = ((array_key_exists('item_verified',$arr))    ? intval($arr['item_verified'])          : $orig[0]['item_verified'] );
    $arr['item_retained']    = ((array_key_exists('item_retained',$arr))    ? intval($arr['item_retained'])          : $orig[0]['item_retained'] );
    $arr['item_rss']    = ((array_key_exists('item_rss',$arr))    ? intval($arr['item_rss'])          : $orig[0]['item_rss'] );
    $arr['item_deleted']    = ((array_key_exists('item_deleted',$arr))    ? intval($arr['item_deleted'])          : $orig[0]['item_deleted'] );
    $arr['item_type']    = ((array_key_exists('item_type',$arr))    ? intval($arr['item_type'])          : $orig[0]['item_type'] );
    $arr['item_hidden']    = ((array_key_exists('item_hidden',$arr))    ? intval($arr['item_hidden'])          : $orig[0]['item_hidden'] );
    $arr['item_unpublished']    = ((array_key_exists('item_unpublished',$arr))    ? intval($arr['item_unpublished'])          : $orig[0]['item_unpublished'] );
    $arr['item_delayed']    = ((array_key_exists('item_delayed',$arr))    ? intval($arr['item_delayed'])          : $orig[0]['item_delayed'] );
    $arr['item_pending_remove']    = ((array_key_exists('item_pending_remove',$arr))    ? intval($arr['item_pending_remove'])          : $orig[0]['item_pending_remove'] );
    $arr['item_blocked']    = ((array_key_exists('item_blocked',$arr))    ? intval($arr['item_blocked'])          : $orig[0]['item_blocked'] );

    $arr['sig']           = ((x($arr,'sig'))           ? $arr['sig']                         : '');
    $arr['layout_mid']    = ((array_key_exists('layout_mid',$arr)) ? dbesc($arr['layout_mid'])           : $orig[0]['layout_mid'] );

    $arr['public_policy'] = '';
    $arr['comment_policy'] = ((x($arr,'comment_policy')) ? notags(trim($arr['comment_policy']))  : $orig[0]['comment_policy'] );

    /**
     * @hooks post_remote_update
     *   Called when processing a remote post that involved an edit or update.
     */
    Hook::call('post_remote_update', $arr);

    if(x($arr, 'cancel')) {
        logger('Post cancelled by plugin.');
        $ret['message'] = 'cancelled.';
        return $ret;
    }

    // pull out all the taxonomy stuff for separate storage

    $terms = null;
    if(array_key_exists('term',$arr)) {
        $terms = $arr['term'];
        unset($arr['term']);
    }

    $meta = null;
    if(array_key_exists('iconfig',$arr)) {
        $meta = $arr['iconfig'];
        unset($arr['iconfig']);
    }

    logger('item_store_update: ' . print_r($arr,true), LOGGER_DATA);
    logger('item_store_update_terms: ' . print_r($terms, true), LOGGER_DATA);

    $str = '';
    foreach($arr as $k => $v) {
        if($str)
            $str .= ",";
        $str .= " " . TQUOT . dbesc($k) . TQUOT . " = '" . dbesc($v) . "' ";
    }

    $r = dbq("update item set " . $str . " where id = " . $orig_post_id );

    if($r)
        logger('Updated item ' . $orig_post_id, LOGGER_DEBUG);
    else {
        logger('Could not update item');
        $ret['message'] = 'DB update failed.';
        return $ret;
    }

    // fetch an unescaped complete copy of the stored item

    $r = q("select * from item where id = %d",
        intval($orig_post_id)
    );
    if($r)
        $arr = $r[0];


    $r = q("delete from term where oid = %d and otype = %d",
        intval($orig_post_id),
        intval(TERM_OBJ_POST)
    );

    if(is_array($terms)) {
        foreach($terms as $t) {
            q("insert into term (uid,oid,otype,ttype,term,url)
                values(%d,%d,%d,%d,'%s','%s') ",
                intval($uid),
                intval($orig_post_id),
                intval(TERM_OBJ_POST),
                intval($t['ttype']),
                dbesc($t['term']),
                dbesc($t['url'])
            );
        }
        $arr['term'] = $terms;
    }

    $r = q("delete from iconfig where iid = %d",
        intval($orig_post_id)
    );

    if($meta) {
        foreach($meta as $m) {
            set_iconfig($orig_post_id,$m['cat'],$m['k'],$m['v'],$m['sharing']);
        }
        $arr['iconfig'] = $meta;
    }

    $ret['item'] = $arr;

    /**
     * @hooks post_remote_update_end
     *   Called after processing a remote post that involved an edit or update.
     */
    Hook::call('post_remote_update_end', $arr);


    if((str_contains($arr['body'], '[embed]')) || (str_contains($arr['body'], '[/img]'))) {
        Run::Summon([ 'Cache_embeds', $orig_post_id ]);
    }

    if($deliver) {
        // don't send notify_comment for edits
        // send_status_notifications($orig_post_id,$arr);
        tag_deliver($uid,$orig_post_id);
    }

    $ret['success'] = true;
    $ret['item_id'] = $orig_post_id;

    return $ret;
}

function item_update_parent_commented($item) {


    $update_parent = true;

    // update the commented timestamp on the parent
    // - unless this is a moderated comment or a potential clone of an older item
    // which we don't wish to bring to the surface. As the queue only holds deliveries
    // for 3 days, it's suspected of being an older cloned item if the creation time
    // is older than that.

    if(intval($item['item_blocked']) === ITEM_MODERATED)
        $update_parent = false;

    if($item['created'] < datetime_convert('','','now - 4 days'))
        $update_parent = false;

    if($update_parent) {
        $z = q("select max(created) as commented from item where parent_mid = '%s' and uid = %d and item_delayed = 0 and item_deleted = 0",
            dbesc($item['parent_mid']),
            intval($item['uid'])
        );

        q("UPDATE item set commented = '%s', changed = '%s' WHERE id = %d",
            dbesc(($z) ? $z[0]['commented'] : datetime_convert()),
            dbesc(datetime_convert()),
            intval($item['parent'])
        );
    }
}


function send_status_notifications($item)
{
    // logger('notifications: ' . print_r($item, true));
    $original_author = false;

    if ($item['mid'] === $item['parent_mid']) {
        if (intval($item['item_blocked']) === ITEM_MODERATED) {
            if (str_contains($item['body'],'[/share]')) {
                preg_match("/portable_id='(.*?)'/ism", $item['body'], $matches);
                logger('matches: ' . print_r($matches, true));
                if ($matches) {
                    $s = q("select * from xchan where xchan_hash = '%s'",
                        dbesc(urldecode($matches[1]))
                    );
                    if ($s) {
                        $original_author = array_shift($s);
                    }
                }
            }
        }
        else {
            return;
        }
    }

    $notify = false;
    $unfollowed = false;

    $parent = 0;
    $thr_parent_id = 0;

    if (array_key_exists('verb', $item) && (activity_match($item['verb'], ACTIVITY_LIKE) || activity_match($item['verb'], ACTIVITY_DISLIKE))) {

        $r = q("select id from item where mid = '%s' and uid = %d limit 1",
            dbesc($item['thr_parent']),
            intval($item['uid'])
        );

        $thr_parent_id = $r[0]['id'];
    }

    $r = Channel::from_id($item['uid']);
    if (!$r) {
        return;
    }

    // my own post - no notification needed
    if ($item['author_xchan'] === $r['channel_hash'] && intval($item['item_blocked']) !== ITEM_MODERATED) {
        return;
    }

    // I'm the owner - notify me

    if ($item['owner_xchan'] === $r['channel_hash']) {
        $notify = true;
    }

    // Was I involved in this conversation?

    $x = q("select * from item where parent_mid = '%s' and uid = %d",
        dbesc($item['parent_mid']),
        intval($item['uid'])
    );
    if ($x) {
        foreach ($x as $xx) {
            if ($xx['author_xchan'] === $r['channel_hash']) {
                $notify = true;

                // check for an unfollow thread activity - we should probably decode the obj and check the id
                // but it will be extremely rare for this to be wrong.

                if (($xx['verb'] === ACTIVITY_IGNORE)
                        && ($xx['obj_type'] === ACTIVITY_OBJ_NOTE || $xx['obj_type'] === ACTIVITY_OBJ_PHOTO)
                        && ($xx['parent'] != $xx['id'])) {
                    $unfollowed = true;
                }
            }
            if ($xx['id'] == $xx['parent']) {
                $parent = $xx['parent'];
            }
        }
    }

    if ($unfollowed) {
        return;
    }

    if (intval($item['item_private']) === 2) {
        $notify_type = NOTIFY_MAIL;
    }
    elseif (intval($item['item_blocked']) === ITEM_MODERATED) {
        $notify_type = NOTIFY_MODERATE;
    }
    elseif ($item['verb'] === 'Announce') {
        $notify_type = NOTIFY_RESHARE;
    }
    else {
        $notify_type = NOTIFY_COMMENT;
    }

    $link =  z_root() . (($notify_type === NOTIFY_MODERATE) ? '/moderate' : '/display' )
            . '/?mid=' . gen_link_id($item['mid']);

    $y = q("select id from notify where link = '%s' and uid = %d limit 1",
        dbesc($link),
        intval($item['uid'])
    );


    if ($y) {
        $notify = false;
    }
    if (! $notify) {
        return;
    }

    Enotify::submit([
        'type'         => $notify_type,
        'from_xchan'   => $original_author ? $original_author['xchan_hash'] : $item['author_xchan'],
        'to_xchan'     => $r['channel_hash'],
        'item'         => $item,
        'link'         => $link,
        'verb'         => $item['verb'],
        'otype'        => 'item',
        'parent'       => $thr_parent_id ?: $parent,
        'parent_mid'   => $thr_parent_id ? $item['thr_parent'] : $item['parent_mid']
    ]);
}

/**
 * @brief Called when we deliver things that might be tagged in ways that require delivery processing.
 *
 * Handles community tagging of posts and also look for mention tags and sets up
 * a second delivery chain if appropriate.
 *
 * @param int $uid
 * @param int $item_id
 */
function tag_deliver($uid, $item_id) {

    $role = get_pconfig($uid,'system','permissions_role');
    $rolesettings = PermissionRoles::role_perms($role);
    $channel_type = isset($rolesettings['channel_type']) ? $rolesettings['channel_type'] : 'normal';

    $is_group = ($channel_type === 'group');
    $is_collection = ($channel_type === 'collection');

    logger('checking tags');
    if ($is_group) {
        logger('Channel is a group.');
    }

    /*
     * Fetch stuff we need - a channel and an item
     */

    $u = Channel::from_id($uid);
    if (! $u) {
        return;
    }

    $i = q("select * from item where id = %d and uid = %d limit 1",
        intval($item_id),
        intval($uid)
    );
    if (! $i) {
        return;
    }

    xchan_query($i,true);
    $i = fetch_post_tags($i);

    $item = array_shift($i);

    if (intval($item['item_uplink']) && $item['source_xchan']
        && intval($item['item_thread_top']) && ($item['edited'] != $item['created'])) {

        // this is an update (edit) to a post which was already processed by us and has a second delivery chain
        // Just start the second delivery chain to deliver the updated post
        // after resetting ownership and permission bits

        logger('updating edited tag_deliver post for ' . $u['channel_address']);
        start_delivery_chain($u, $item, $item_id, false, false, true);
        return;
    }

    // send mail (DM) notifications here, but only for top level posts.
    // followups will be processed by send_status_notifications()

    $mail_notify = false;
    if ((! $item['item_wall']) && intval($item['item_thread_top']) && $item['author_xchan'] !== $u['channel_hash'] && intval($item['item_private']) === 2) {
        Enotify::submit([
            'to_xchan'     => $u['channel_hash'],
            'from_xchan'   => $item['author_xchan'],
            'type'         => NOTIFY_MAIL,
            'item'         => $item,
            'link'         => $item['llink'],
            'verb'         => 'DM',
            'otype'        => 'item'
        ]);
        $mail_notify = true;
    }

    // important - ignore wall posts here else dm's by group owner will be sent to group.

    if ($is_group && intval($item['item_private']) === 2 && intval($item['item_thread_top']) && (! intval($item['item_wall']))) {
        // group delivery via DM - use post_wall permission since send_stream is probably turned off
        // and this will be turned into an embedded wall-to-wall post
        if(perm_is_allowed($uid, $item['author_xchan'], 'post_wall')) {
            logger('group DM delivery for ' . $u['channel_address']);
            start_delivery_chain($u, $item, $item_id, false, true, (($item['edited'] != $item['created']) || $item['item_deleted']));
            q("update item set item_blocked = %d where id = %d",
                intval(ITEM_HIDDEN),
                intval($item_id)
            );
        }
        return;
    }

    // Deliver to group via target collection

    if ($is_group && intval($item['item_thread_top']) && (! intval($item['item_wall'])) && (str_contains($item['tgt_type'], 'Collection')) && $item['target']) {
        // group delivery via target - use post_wall permission since send_stream is probably turned off
        // and this will be turned into an embedded wall-to-wall post
        if (is_array($item['target'])) {
            $a = $item['target'];
        }
        else {
            $a = json_decode($item['target'],true);
        }

        if ($a) {
            $id = ((is_string($a)) ? $a : EMPTY_STR);
            if (is_array($a) && isset($a['id'])) {
                $id = $a['id'];
            }
            if ($id == z_root() . '/outbox/' . $u['channel_address']) {
                if(perm_is_allowed($uid, $item['author_xchan'], 'post_wall')) {
                    logger('group collection delivery for ' . $u['channel_address']);
                    start_delivery_chain($u, $item, $item_id, false, true, (($item['edited'] != $item['created']) || $item['item_deleted']));
                    q("update item set item_blocked = %d where id = %d",
                        intval(ITEM_HIDDEN),
                        intval($item_id)
                    );
                }
                return;
            }
        }
    }

    if ($is_group && intval($item['item_thread_top']) && intval($item['item_wall']) && $item['author_xchan'] !== $item['owner_xchan']) {
        if (strpos($item['body'],'[/share]')) {
            logger('W2W post already shared');
            return;
        }
        // group delivery via W2W
        logger('rewriting W2W post for ' . $u['channel_address']);
        start_delivery_chain($u, $item, $item_id, false, true, (($item['edited'] != $item['created']) || $item['item_deleted']));
        q("update item set item_wall = 0 where id = %d",
            intval($item_id)
        );
        return;
    }

    /*
     * A "union" is a message which our channel has sourced from another channel.
     * This sets up a second delivery chain just like forum tags do.
     * Find out if this is a source-able post.
     */

    $union = check_item_source($uid,$item);
    if ($union) {
        logger('check_item_source returns true');
    }

    // This might be a followup (e.g. comment) to an already uplinked item
    // If so setup a second delivery chain

    if (! intval($item['item_thread_top'])) {
        $x = q("select * from item where id = parent and parent = %d and uid = %d limit 1",
            intval($item['parent']),
            intval($uid)
        );

        if ($x) {

            // group comments don't normally require a second delivery chain
            // but we create a linked Announce so they will show up in the home timeline
            // on microblog platforms and this creates a second delivery chain

            if (($is_group || $union) && intval($x[0]['item_wall'])) {
                // don't let the forked delivery chain recurse
                if ($item['verb'] === 'Announce' && $item['author_xchan'] === $u['channel_hash']) {
                    return;
                }
                // don't boost moderated content until it has been approved
                if (intval($item['item_blocked']) === ITEM_MODERATED) {
                    return;
                }

                // don't boost likes and other response activities as it is likely that
                // few platforms will handle this in an elegant way

                if (ActivityStreams::is_response_activity($item['verb'])) {
                    return;
                }
                logger('group_comment');
                start_delivery_chain($u, $item, $item_id, $x[0], true, (($item['edited'] != $item['created']) || $item['item_deleted']));
            }
            elseif (intval($x[0]['item_uplink'])) {
                start_delivery_chain($u,$item,$item_id,$x[0]);
            }
        }
    }


    /*
     * Now we've got those out of the way. Let's see if this is a post that's tagged for re-delivery
     */


    $terms = ((isset($item['term'])) ? get_terms_oftype($item['term'],[TERM_MENTION, TERM_FORUM]) : false);

    $pterms = ((isset($item['term'])) ? get_terms_oftype($item['term'], [TERM_PCATEGORY, TERM_HASHTAG] ) : false);

    if ($terms) {
        logger('Post mentions: ' . print_r($terms,true), LOGGER_DATA);
    }

    if ($pterms) {
        logger('Post collections: ' . print_r($pterms,true), LOGGER_DATA);
    }

    $link = normalise_link($u['xchan_url']);

    if ($terms) {
        foreach ($terms as $term) {

            if (! link_compare($term['url'],$link)) {
                continue;
            }
            logger('Mention found for ' . $u['channel_name']);

            q("update item set item_mentionsme = 1 where id = %d",
                intval($item_id)
            );

            // At this point we've determined that the person receiving this post was mentioned in it or it is a union.
            // Now let's check if this mention was inside a reshare so we don't spam a forum

            $body = strip_share_content($item['body']);

            $tagged = false;
            $matches = [];

            $pattern = '/[!@]!?\[[uz]rl=' . preg_quote($term['url'],'/') . '](.*?)\[\/[uz]rl]/';
            if (preg_match($pattern,$body,$matches))
                $tagged = true;

            $pattern = '/\[[uz]rl=' . preg_quote($term['url'],'/') . '][!@](.*?)\[\/[uz]rl]/';
            if (preg_match($pattern,$body,$matches))
                $tagged = true;


            if (! $tagged ) {
                logger('Mention was in a reshare - ignoring');
                continue;
            }

            $arr = [
                'channel_id' => $uid,
                'item' => $item,
                'body' => $body
            ];

            /**
             * @hooks tagged
             *   Called when a delivery is processed which results in you being tagged.
             *   * \e number \b channel_id
             *   * \e array \b item
             *   * \e string \b body
             */

            Hook::call('tagged', $arr);

            /**
             * post to a group via group tags (!group) or normal @-mentions *only if* the group is public
             * but let the owner change this with a hidden pconfig and either allow
             * or deny this option regardless of the type of group
             */

            if ($is_group && intval($item['item_thread_top']) && (! intval($item['item_wall']))) {
                if ((intval($term['ttype']) === TERM_FORUM || get_pconfig($uid,'system','post_via_mentions',in_array($role,['forum','forum_moderated']))) && perm_is_allowed($uid, $item['author_xchan'], 'post_wall')) {
                    logger('group mention delivery for ' . $u['channel_address']);
                    start_delivery_chain($u, $item, $item_id, false, true, (($item['edited'] != $item['created']) || $item['item_deleted']));
                    q("update item set item_blocked = %d where id = %d",
                        intval(ITEM_HIDDEN),
                        intval($item_id)
                    );
                }
            }

            /*
             * Send a mention notification - unless we just sent a mail notification for the same item
             */

            if (! $mail_notify) {
                Enotify::submit([
                    'to_xchan'     => $u['channel_hash'],
                    'from_xchan'   => $item['author_xchan'],
                    'type'         => NOTIFY_TAGSELF,
                    'item'         => $item,
                    'link'         => $item['llink'],
                    'verb'         => ACTIVITY_TAG,
                    'otype'        => 'item'
                ]);
            }
        }
    }
    if ($is_collection && $pterms) {
        foreach ($pterms as $term) {

            $ptagged = false;

            if (link_compare($term['url'],$link)) {
                $ptagged = true;
            }
            elseif ($term['ttype'] === TERM_HASHTAG && strtolower($term['term']) === strtolower($u['channel_address'])) {
                $ptagged = true;
            }

            if (! $ptagged) {
                continue;
            }

            logger('Collection post found for ' . $u['channel_name']);

            // ptagged - keep going, next check permissions

            if ((! perm_is_allowed($uid, $item['author_xchan'], 'write_collection')) && ($item['author_xchan'] !== $u['channel_parent'])) {
                logger('tag_delivery denied for uid ' . $uid . ' and xchan ' . $item['author_xchan']);
                continue;
            }

            // tgroup delivery - set up a second delivery chain
            // prevent delivery looping - only proceed
            // if the message originated elsewhere and is a top-level post

            if (intval($item['item_wall']) || intval($item['item_origin']) || (! intval($item['item_thread_top'])) || ($item['id'] != $item['parent'])) {
                logger('Item was local or a comment. rejected.');
                continue;
            }

            logger('Creating second delivery chain.');
            start_delivery_chain($u,$item,$item_id, false);

        }
    }

    if ($union) {
        if (intval($item['item_wall']) || intval($item['item_origin']) || (! intval($item['item_thread_top'])) || ($item['id'] != $item['parent'])) {
            logger('Item was local or a comment. rejected.');
            return;
        }

        logger('Creating second delivery chain.');
        start_delivery_chain($u,$item,$item_id,false);

    }

}

/**
 * @brief This function is called pre-deliver to see if a post matches the criteria to be tag delivered.
 *
 * We don't actually do anything except check that it matches the criteria.
 * This is so that the channel with tag_delivery enabled can receive the post even if they turn off
 * permissions for the sender to send their stream. tag_deliver() can't be called until the post is actually stored.
 * By then it would be too late to reject it.
 *
 * @param number $uid A chnnel_id
 * @param array $item
 * @return boolean
 */

function tgroup_check($uid, $item) {


    $role = get_pconfig($uid,'system','permissions_role');
    $rolesettings = PermissionRoles::role_perms($role);
    $channel_type = isset($rolesettings['channel_type']) ? $rolesettings['channel_type'] : 'normal';

    $is_group = $channel_type === 'group';
    $is_collection = $channel_type === 'collection';

    // If a comment, check if we have already accepted the top level post as an uplink
    // Applies to collections only at this time
    // @FIXME We need a comment clause for groups

    if ($item['mid'] !== $item['parent_mid']) {
        $r = q("select id from item where mid = '%s' and uid = %d and item_uplink = 1 limit 1",
            dbesc($item['parent_mid']),
            intval($uid)
        );
        if ($r) {
            return true;
        }
    }

    $u = Channel::from_id($uid);
    if (! $u) {
        return false;
    }

    // post to group via DM

    if ($is_group) {
        if (intval($item['item_private']) === 2 && $item['mid'] === $item['parent_mid']) {
            return true;
        }

        if ($item['mid'] === $item['parent_mid'] && (! intval($item['item_wall'])) && (str_contains($item['tgt_type'], 'Collection')) && $item['target']) {
            // accept posts to collections only if the collection belongs to us
            if ((is_string($item['target']) && str_contains($item['target'], z_root()))
                || (isset($item['target']['id']) && str_contains($item['target']['id'], z_root()))) {
                return true;
            }
        }

        if (get_pconfig($uid,'system','post_via_mentions',in_array($role, ['forum','forum_moderated'])) && i_am_mentioned($u,$item)) {
            return true;
        }
        elseif (i_am_mentioned($u,$item, true)) {
            return true;
        }
    }

    // see if we already have this item. Maybe it is being updated.

    $r = q("select id from item where mid = '%s' and uid = %d limit 1",
        dbesc($item['mid']),
        intval($uid)
    );

    if ($r) {
        return true;
    }


    if (($is_collection) && (perm_is_allowed($uid, $item['author_xchan'], 'write_collection') || $item['author_xchan'] === $u['channel_parent'])) {
        return true;
    }

    // return true if we are mentioned, and we permit delivery of mentions from strangers

    if (PConfig::Get($uid, 'system','permit_all_mentions') && i_am_mentioned($u,$item)) {
        return true;
    }

    if (PConfig::Get($uid, 'system','permit_all_likes') && $item['verb'] === 'Like' && $item['obj_type'] === 'Note') {
        return true;
    }
    
    $tag_result = false;
    $terms = ((isset($item['term'])) ? get_terms_oftype($item['term'],TERM_HASHTAG) : false);
    if ($terms) {
        $followed_tags = PConfig::Get($uid,'system','followed_tags');
        if (! (is_array($followed_tags) && $followed_tags)) {
            return false;
        }

        foreach ($terms as $term) {
            foreach ($followed_tags as $tag) {
                if (strcasecmp($term['term'],$tag) === 0) {
                    $tag_result = true;
                }
            }
        }
        $unless = intval(PConfig::Get($uid, 'system', 'unless_tag_count',
            Config::Get('system', 'unless_tag_count', 20)));
        if ($unless && count($terms) > $unless) {
            $tag_result= false;
        }
    }
    return $tag_result;
}


function i_am_mentioned($channel,$item,$check_groups = false) {

    $link = $channel['xchan_url'];

    $body = preg_replace('/\[share(.*?)\[\/share]/','',$item['body']);

    $tagged = false;
    $matches = [];
    $tagtype = $check_groups ? TERM_FORUM : TERM_MENTION;
    $terms = ((isset($item['term'])) ? get_terms_oftype($item['term'], $tagtype) : false);

    if ($terms) {
        foreach ($terms as $term) {
            if ($link === $term['url']) {
                $pattern = '/[!@]!?\[[uz]rl=' . preg_quote($term['url'],'/') . '](.*?)\[\/[uz]rl]/';
                if (preg_match($pattern,$body,$matches)) {
                    $tagged = true;
                }
                $pattern = '/\[[uz]rl=' . preg_quote($term['url'],'/') . '][!@](.*?)\[\/[uz]rl]/';
                if (preg_match($pattern,$body,$matches)) {
                    $tagged = true;
                }
            }
        }
    }
    $unless = intval(get_pconfig($channel['channel_id'], 'system', 'unless_mention_count', get_config('system', 'unless_mention_count', 20)));
    if ($unless && $terms && count($terms) > $unless) {
        $tagged = false;
    }
    return $tagged;
}


/**
 * Sourced and tag-delivered posts are re-targetted for delivery to the connections of the channel
 * receiving the post. This starts the second delivery chain, by resetting permissions and ensuring
 * that ITEM_UPLINK is set on the parent post, and storing the current owner_xchan as the source_xchan.
 * We'll become the new owner. If called without $parent, this *is* the parent post.
 *
 * @param array $channel
 * @param array $item
 * @param int $item_id
 * @param bool|array $parent
 */
function start_delivery_chain($channel, $item, $item_id, bool|array $parent, $group = false, $edit = false) {

   // btlogger('start_chain: ' . $channel['channel_id'] . ' item: ' . $item_id);
    $moderated = perm_is_allowed($channel['channel_id'], $item['author_xchan'], 'moderated');

    $source = check_item_source($channel['channel_id'],$item);

    // This creates an embedded share authored by the group actor.
    // The original message is no longer needed and its presence can cause
    // confusion so make it hidden.

    if (!$parent) {

        $arr = [];

        // hide original message
        q("update item set item_hidden = 1 where id = %d",
            intval($item_id)
        );

        if ($edit) {
            // process edit or delete action
            $r = q("select * from item where source_xchan = '%s' and body like '%s' and uid = %d limit 1",
                dbesc($item['owner_xchan']),
                dbesc("%message_id='" . $item['mid'] . "'%"),
                intval($channel['channel_id'])
            );
            if ($r) {
                if (intval($item['item_deleted'])) {
                    drop_item($r[0]['id'],DROPITEM_PHASE1);
                    Run::Summon([ 'Notifier','drop',$r[0]['id'] ]);
                    return;
                }
                $arr['id'] = intval($r[0]['id']);
                $arr['parent'] = intval($r[0]['parent']);
                $arr['mid'] = $r[0]['mid'];
                $arr['parent_mid'] = $r[0]['parent_mid'];
                $arr['edited'] = datetime_convert();
            }
            else {
                logger('unable to locate original group post ' . $item['mid']);
                return;
            }

        }
        else {
            $arr['mid'] = item_message_id();
            $arr['parent_mid'] = $arr['mid'];
            IConfig::Set($arr,'activitypub','context', str_replace('/item/','/conversation/',$arr['mid']));
        }

        $arr['aid'] = $channel['channel_account_id'];
        $arr['uid'] = $channel['channel_id'];

        // WARNING: the presence of both source_xchan and non-zero item_uplink here will cause a delivery loop
        $arr['item_uplink']  = 0;
        $arr['source_xchan'] = $item['author_xchan'];

        $arr['item_private'] = (($channel['channel_allow_cid'] || $channel['channel_allow_gid'] || $channel['channel_deny_cid'] || $channel['channel_deny_gid']) ? 1 : 0);

        $arr['item_origin'] = 1;

        $arr['item_wall'] = 1;
        $arr['item_thread_top'] = 1;

        if ($moderated) {
            $arr['item_blocked'] = ITEM_MODERATED;
        }

        $bb = "[share author='" . urlencode($item['author']['xchan_name']) .
            "' profile='"       . $item['author']['xchan_url'] .
            "' portable_id='"   . $item['author']['xchan_hash'] .
            "' avatar='"        . $item['author']['xchan_photo_s'] .
            "' link='"          . $item['plink'] .
            "' auth='"          . ((isOWAEnabled($item['author']['xchan_url'])) ? 'true' : 'false') .
            "' posted='"        . $item['created'] .
            "' message_id='"    . $item['mid'] .
        "']";
        if ($item['title']) {
            $bb .= '[b]' . $item['title'] . '[/b]' . "\r\n";
            $arr['title'] = $item['title'];
        }
        $bb .= $item['body'];
        $bb .= "[/share]";

        $arr['body'] = $bb;

        $tagpref = intval(PConfig::Get($channel['channel_id'], 'system', 'tag_username', Config::Get('system', 'tag_username', false)));

        $mention = $item['author']['xchan_name'];

        if ($tagpref === 1 && $item['author']['xchan_addr']) {
            $mention = $item['author']['xchan_addr'];
        }
        if ($tagpref === 2 && $item['author']['xchan_addr']) {
            $mention = sprintf(t('%1$s (%2$s)'), $item['author']['xchan_name'], $item['author']['xchan_addr']);
        }

        $arr['body'] .= "\n" . '@[zrl=' . $item['author']['xchan_url'] . ']' . $mention . '[/zrl]';

        // Conversational objects shouldn't be copied, but other objects should.
        if (in_array($item['obj_type'], [ 'Image', 'Event', 'Question'])) {
            $arr['obj'] = $item['obj'];
            $t = json_decode($arr['obj'],true);
            if ($t !== NULL) {
                $arr['obj'] = $t;
            }
            $arr['obj']['content'] = bbcode($bb, [ 'export' => true ]);
            $arr['obj']['source']['content'] = $bb;
            $arr['obj']['id'] = $arr['mid'];

            if (! array_path_exists('obj/source/mediaType',$arr)) {
                $arr['obj']['source']['mediaType'] = 'text/x-multicode';
            }
        }

        $arr['tgt_type'] = $item['tgt_type'];

        if (is_array($item['target'])) {
            $arr['target'] = $item['target']['id'];
        }
        else {
            $arr['target'] = $item['target'];
        }

        // Add a mention for the author.
        $arr['term'] = ($item['term']) ?: [];
        $arr['term'][] = [
            'uid' => $channel['channel_id'],
            'ttype' => TERM_MENTION,
            'otype' => TERM_OBJ_POST,
            'term' => '@' . $item['author']['xchan_addr'],
            'url' => $item['author']['xchan_url']
        ];

        $arr['author_xchan'] = $channel['channel_hash'];
        $arr['owner_xchan']  = $channel['channel_hash'];

        $arr['obj_type'] = $item['obj_type'];

        $arr['verb'] = 'Create';

        $arr['item_restrict'] = 1;

        $arr['allow_cid'] = $channel['channel_allow_cid'];
        $arr['allow_gid'] = $channel['channel_allow_gid'];
        $arr['deny_cid']  = $channel['channel_deny_cid'];
        $arr['deny_gid']  = $channel['channel_deny_gid'];
        $arr['comment_policy'] = map_scope(PermissionLimits::Get($channel['channel_id'],'post_comments'));

        $merge = (($item['attach']) ?: []);
        if (is_string($merge)) {
            $merge = json_decode($merge, true);
        }
        if ($merge) {
            $arr['attach'] = array_merge($merge, [['type' => 'application/activity+json', 'href' => $item['mid']]]);
        }
        else {
            $arr['attach'] = [['type' => 'application/activity+json', 'href' => $item['mid']]];
        }
        $arr['replyto'] = z_root() . '/channel/' . $channel['channel_address'];

        if ($arr['id']) {
            $post = item_store_update($arr);
        }
        else {
            $post = item_store($arr);
        }

        $post_id = $post['item_id'];

        if ($source && $post_id && !$edit) {
            $t = trim($source['src_tag']);
            if ($t) {
                $tags = explode(',', $t);
                if ($tags) {
                    foreach ($tags as $tt) {
                        $tt = trim($tt);
                        if ($tt) {
                            q("insert into term (uid,oid,otype,ttype,term,url)
                            values(%d,%d,%d,%d,'%s','%s') ",
                                intval($channel['channel_id']),
                                intval($post_id),
                                intval(TERM_OBJ_POST),
                                intval(TERM_CATEGORY),
                                dbesc($tt),
                                dbesc(z_root() . '/channel/' . $channel['channel_address'] . '?f=&cat=' . urlencode($tt))
                            );
                        }
                    }
                }
            }
        }

        if($post_id) {
            Run::Summon([ 'Notifier','tgroup',$post_id ]);
        }

        q("update channel set channel_lastpost = '%s' where channel_id = %d",
            dbesc(datetime_convert()),
            intval($channel['channel_id'])
        );

        return;
    }


    // Send Announce activities for group comments, so they will show up in microblog streams

    if ($parent) {
        logger('comment arrived for new delivery chain', LOGGER_DEBUG);
        $arr = [];

        // don't let this recurse. We checked for this before calling, but this ensures
        // it doesn't sneak through another way because recursion is nasty.

        if ($item['verb'] === 'Announce' && $item['author_xchan'] === $channel['channel_hash']) {
            return;
        }

        // Don't send Announce activities for poll responses.

        if ($item['obj_type'] === 'Answer') {
            return;
        }

        if ($edit) {
            if (intval($item['item_deleted'])) {
                drop_item($item['id'],DROPITEM_PHASE1);
                Run::Summon(['Notifier', 'drop', $item['id'] ]);
                return;
            }
            return;
        }
        else {
            $arr['mid'] = item_message_id();
            $arr['parent_mid'] = $item['parent_mid'];
            IConfig::Set($arr,'activitypub','context', str_replace('/item/','/conversation/',$item['parent_mid']));
        }

        $arr['aid'] = $channel['channel_account_id'];
        $arr['uid'] = $channel['channel_id'];

        $arr['verb'] = 'Announce';

        if (is_array($item['obj'])) {
            $arr['obj'] = $item['obj'];
        }
        elseif (is_string($item['obj']) && strlen($item['obj'])) {
            $arr['obj'] = json_decode($item['obj'],true);
        }

        if (! $arr['obj']) {
            $arr['obj'] = $item['mid'];
        }

        if (is_array($arr['obj'])) {
            $obj_actor = ((isset($arr['obj']['actor'])) ? $arr['obj']['actor'] : $arr['obj']['attributedTo']);
            $mention = Activity::get_actor_bbmention($obj_actor);
            $arr['body'] = sprintf( t('&#x1F4E2; Repeated %1$s\'s %2$s'), $mention, $arr['obj']['type']);
        }

        $arr['author_xchan'] = $channel['channel_hash'];
        $arr['item_wall'] = 1;
        $arr['item_private'] = (($channel['channel_allow_cid'] || $channel['channel_allow_gid'] || $channel['channel_deny_cid'] || $channel['channel_deny_gid']) ? 1 : 0);
        $arr['item_origin'] = 1;
        $arr['item_thread_top'] = 0;
        $arr['allow_cid'] = $channel['channel_allow_cid'];
        $arr['allow_gid'] = $channel['channel_allow_gid'];
        $arr['deny_cid']  = $channel['channel_deny_cid'];
        $arr['deny_gid']  = $channel['channel_deny_gid'];
        $arr['comment_policy'] = map_scope(PermissionLimits::Get($channel['channel_id'],'post_comments'));
        $arr['replyto'] = z_root() . '/channel/' . $channel['channel_address'];

        $post = item_store($arr);
        $post_id = $post['item_id'];

        if ($post_id) {
            Run::Summon([ 'Notifier','tgroup',$post_id ]);
        }

        q("update channel set channel_lastpost = '%s' where channel_id = %d",
            dbesc(datetime_convert()),
            intval($channel['channel_id'])
        );

        return;
    }
}

/**
 * @brief
 *
 * Checks to see if this item owner is referenced as a source for this channel and if the post
 * matches the rules for inclusion in this channel. Returns true if we should create a second delivery
 * chain and false if none of the rules apply, or if the item is private.
 *
 * @param int $uid
 * @param array $item
 */
function check_item_source($uid, $item) {

    logger('source: uid: ' . $uid, LOGGER_DEBUG);
    $xchan = ((isset($item['source_xchan']) && $item['source_xchan'] && isset($item['item_uplink']) && intval($item['item_uplink'])) ?  $item['source_xchan'] : $item['owner_xchan']);

    $linkedIds = null;

    $channel = Channel::from_id($uid);
    if ($channel) {
        $linkedIds = q("select * from linkid where ident = '%s' and sigtype = %d",
            dbesc($channel['channel_hash']),
            intval(IDLINK_RELME)
        );
    }

    $r = q("select * from source where src_channel_id = %d and ( src_xchan = '%s' or src_xchan = '*' ) limit 1",
        intval($uid),
        dbesc($xchan)
    );

    if (! $r) {
        logger('source: no source record for this channel and source', LOGGER_DEBUG);
        return false;
    }

    $x = q("select abook_feed from abook where abook_channel = %d and abook_xchan = '%s' limit 1",
        intval($uid),
        dbesc($xchan)
    );

    if (! $x) {
        logger('source: not connected to this channel.');
        return false;
    }

    if (! their_perms_contains($uid,$xchan,'republish')) {
        if ($linkedIds) {
            foreach ($linkedIds as $linkId) {
                if ($linkId['link'] === $item['owner_xchan'] || $linkId['link'] === $item['owner']['xchan_url']) {
                    logger('source: success - linked identity');
                    return true;
                }
            }
        }
        logger('source: no republish permission');
        return false;
    }

    if ($item['item_private'] && (! intval($x[0]['abook_feed']))) {
        logger('source: item is private');
        return false;
    }

    if ($r[0]['src_channel_xchan'] === $xchan) {
        logger('source: cannot source yourself');
        return false;
    }

    if (! $r[0]['src_patt']) {
        logger('source: success');
        return array_shift($r);
    }

    if (MessageFilter::evaluate($item, $r[0]['src_patt'], EMPTY_STR)) {
        logger('source: text filter success');
        return array_shift($r);
    }

    logger('source: filter fail');
    return false;
}

// Checks an incoming item against the per-channel and per-connection content filter.
// This implements the backend of the 'Content Filter' system app

function post_is_importable($channel_id, $item, $abook) {

    if (! $item) {
        return false;
    }

    if (! Apps::system_app_installed($channel_id, 'Content Filter')) {
        return true;
    }

    $text = prepare_text($item['body'],((isset($item['mimetype'])) ? $item['mimetype'] : 'text/x-multicode'));
    $text = html2plain((isset($item['title']) && $item['title']) ? $item['title'] . ' ' . $text : $text);

    $incl = PConfig::Get($channel_id, 'system', 'message_filter_incl', EMPTY_STR);
    $excl = PConfig::Get($channel_id, 'system', 'message_filter_excl', EMPTY_STR);
    if ($incl || $excl) {
        $x = MessageFilter::evaluate($item, $incl, $excl, ['plaintext' => $text]);
        if (! $x) {
            logger('MessageFilter: channel blocked content', LOGGER_DEBUG, LOG_INFO);
            return false;
        }
    }

    if (! $abook) {
        return true;
    }

    foreach ($abook  as  $ab) {
        // check eligibility
        if (intval($ab['abook_self'])) {
            continue;
        }
        if (! ($ab['abook_incl'] || $ab['abook_excl']) ) {
            continue;
        }
        $evaluator = MessageFilter::evaluate($item, $ab['abook_incl'], $ab['abook_excl'], ['plaintext' => $text]);
        // A negative assessment for any individual connections is an instant fail.
        if (! $evaluator) {
            return false;
        }
    }
    return true;
}


function has_permissions($obj) {
    return (! (empty($obj['allow_cid']) && empty($obj['allow_gid'])
        && empty($obj['deny_cid']) && empty($obj['deny_gid'])));
}

function compare_permissions($obj1,$obj2) {
    // first part is easy. Check that these are exactly the same.
    if (($obj1['allow_cid'] == $obj2['allow_cid'])
        && ($obj1['allow_gid'] == $obj2['allow_gid'])
        && ($obj1['deny_cid'] == $obj2['deny_cid'])
        && ($obj1['deny_gid'] == $obj2['deny_gid'])) {
        return true;
    }

    // This is harder. Parse all the permissions and compare the resulting set.

    $recipients1 = enumerate_permissions($obj1);
    $recipients2 = enumerate_permissions($obj2);
    sort($recipients1);
    sort($recipients2);
    if ($recipients1 == $recipients2) {
        return true;
    }
    return false;
}

/**
 * @brief Returns an array of connection identifiers that are allowed to see this object.
 *
 * @param object $obj
 * @return array
 */
function enumerate_permissions($obj) {

    $allow_people = expand_acl($obj['allow_cid']);
    $allow_groups = AccessList::expand(expand_acl($obj['allow_gid']));
    $deny_people  = expand_acl($obj['deny_cid']);
    $deny_groups  = AccessList::expand(expand_acl($obj['deny_gid']));
    $recipients   = array_unique(array_merge($allow_people,$allow_groups));
    $deny         = array_unique(array_merge($deny_people,$deny_groups));
    $recipients   = array_diff($recipients,$deny);

    return $recipients;
}


function item_expire($uid,$days,$comment_days = 7) {

    if ((! $uid) || ($days < 1)) {
        return;
    }

    if (! $comment_days) {
        $comment_days = 7;
    }

    // $expire_stream_only = save your own wall posts
    // and just expire conversations started by others
    // do not enable this until we can pass bulk delete messages through zot
    //    $expire_stream_only = get_pconfig($uid,'expire','stream_only');

    $expire_stream_only = 1;

    $sql_extra = ((intval($expire_stream_only)) ? " AND item_wall = 0 " : "");

    // We need to set an arbitrary limit on the number of records to be expired to
    // prevent memory exhaustion. The site admin can configure it to something else
    // if they desire/require.

    $expire_limit = get_config('system','expire_limit');
    if (! intval($expire_limit)) {
        $expire_limit = 5000;
    }

    $item_normal = item_normal();

    $r = q("SELECT id FROM item
        WHERE uid = %d
        AND created < %s - INTERVAL %s
        AND commented < %s - INTERVAL %s
        AND item_retained = 0
        AND item_thread_top = 1
        AND resource_type = ''
        AND item_starred = 0
        $sql_extra $item_normal LIMIT $expire_limit ",
        intval($uid),
        db_utcnow(),
        db_quoteinterval(intval($days) . ' DAY'),
        db_utcnow(),
        db_quoteinterval(intval($comment_days) . ' DAY')
    );

    if (! $r) {
        return;
    }

    $r = fetch_post_tags($r);

    foreach ($r as $item) {

        // don't expire filed items

        $terms = get_terms_oftype($item['term'],TERM_FILE);
        if ($terms) {
            retain_item($item['id']);
            continue;
        }

        // don't expire pinned items either

        $pinned = PConfig::Get($item['uid'], 'pinned', $item['item_type'], []);
        if (in_array($item['mid'], $pinned)) {
            retain_item($item['id']);
            continue;
        }

        drop_item($item['id'], expire: true);
    }

}

function retain_item($id) {
    $r = q("update item set item_retained = 1 where id = %d",
        intval($id)
    );
}

// Items is array of item.id

function drop_items($items, $stage = DROPITEM_NORMAL, $force = false, $expire = false) {

    $uid = 0;

    if (count($items)) {
        foreach ($items as $item) {
            $owner = drop_item($item, $stage, $force, $expire);
            if ($owner && (! $uid)) {
                $uid = $owner;
            }
        }
    }

    // multiple threads may have been deleted, send an expire notification

    if ($uid) {
        Run::Summon(['Notifier', 'expire', $uid]);
    }
}


// Delete item with given item $id. $interactive means we're running interactively, and must check
// permissions to carry out this act. If it is non-interactive, we are deleting something at the
// system's request and do not check permission. This is very important to know.

// Some deletion requests (those coming from remote sites) must be staged.
// $stage = 0 => unstaged
// $stage = 1 => set deleted flag on the item and perform intial notifications
// $stage = 2 => perform low level delete at a later stage

function drop_item($id, $stage = DROPITEM_NORMAL, $force = false, $uid = 0, $observer_hash = '', $expire = false) {

    // locate item to be deleted

    $r = q("SELECT * FROM item WHERE id = %d",
        intval($id)
    );

    if ((! $r) || (intval($r[0]['item_deleted']) && ($stage === DROPITEM_NORMAL))) {
        return false;
    }

    $item = array_shift($r);

    $ok_to_delete = false;

    // admin deletion

    if (is_site_admin()) {
        $ok_to_delete = true;
    }

    // owner deletion
    if (local_channel() && local_channel() == $item['uid']) {
        $ok_to_delete = true;
    }

    // remote delete when nobody is authenticated (called from Libzot)
    if ($uid && intval($uid) === intval($item['uid'])) {
        $ok_to_delete = true;
    }


    // author deletion
    if ($observer_hash) {
        $observer = ['xchan_hash' => $observer_hash];
    }
    else {
        $observer = App::get_observer();
    }
    
    if ($observer && $observer['xchan_hash'] && ($observer['xchan_hash'] === $item['author_xchan'])) {
        $ok_to_delete = true;
    }

    if ($observer && $observer['xchan_hash'] && ($observer['xchan_hash'] === $item['owner_xchan'])) {
        $ok_to_delete = true;
    }

    if ($ok_to_delete) {

        $r = q("UPDATE item SET item_deleted = 1 WHERE id = %d",
            intval($item['id'])
        );

        if ($item['resource_type'] === 'event' ) {
            q("delete from event where event_hash = '%s' and uid = %d",
                dbesc($item['resource_id']),
                intval($item['uid'])
            );
        }

        if ($item['resource_type'] === 'photo' ) {
            attach_delete($item['uid'], $item['resource_id'], true);
        }

        $arr = [
            'item' => $item,
            'stage' => $stage
        ];
        /**
         * @hooks drop_item
         *   Called when an 'item' is removed.
         */
        Hook::call('drop_item', $arr);

        $notify_id = intval($item['id']);

        $items = q("select * from item where parent = %d and uid = %d",
            intval($item['id']),
            intval($item['uid'])
        );
        if ($items) {
            foreach ($items as $i) {
                delete_item_lowlevel($i, $stage, $force, $expire);
            }
        }
        else {
            delete_item_lowlevel($item, $stage, $force, $expire);
        }

        return true;
    }
    else {
        return false;
    }
}

/**
 * @warning This function does not check for permission and does not send
 * notifications and does not check recursion.
 * It merely destroys all resources associated with an item.
 * Please do not use without a suitable wrapper.
 *
 * @param array $item
 * @param int $stage
 * @param bool $force
 * @return bool
 */
function delete_item_lowlevel($item, $stage = DROPITEM_NORMAL, $force = false, $expire = false) {


    logger('item: ' . $item['id'] . ' stage: ' . $stage . ' force: ' . ($force) ? 'true' : 'false', LOGGER_DATA);

    if (!$expire) {
        Tombstone::store($item['mid'], $item['uid']);
    }
    
    match ($stage) {
        DROPITEM_PHASE2 => q("UPDATE item SET item_pending_remove = 1, body = '', title = '',
                changed = '%s', edited = '%s'  WHERE id = %d",
            dbesc(datetime_convert()),
            dbesc(datetime_convert()),
            intval($item['id'])
        ),
        DROPITEM_PHASE1 => q("UPDATE item set item_deleted = 1, changed = '%s', edited = '%s' where id = %d",
            dbesc(datetime_convert()),
            dbesc(datetime_convert()),
            intval($item['id'])
        ),
        default => q("DELETE FROM item WHERE id = %d",
            intval($item['id'])
        ),
    };

    // immediately remove any undesired profile likes.

    q("delete from likes where iid = %d and channel_id = %d",
        intval($item['id']),
        intval($item['uid'])
    );


    // network deletion request. Keep the message structure so that we can deliver delete notifications.
    // Come back after several days to do the lowlevel delete (DROPITEM_PHASE2).

    if ($stage == DROPITEM_PHASE1) {
        return true;
    }

    $r = q("delete from term where otype = %d and oid = %d",
        intval(TERM_OBJ_POST),
        intval($item['id'])
    );

    q("delete from iconfig where iid = %d",
        intval($item['id'])
    );

    $n = q("select id from item where mid = '%s'",
        dbesc($item['mid'])
    );
    if (!$n) {
        ObjCache::Delete($item['mid']);
    }

    q("delete from term where oid = %d and otype = %d",
        intval($item['id']),
        intval(TERM_OBJ_POST)
    );

    // remove delivery reports

    $c = q("select channel_hash from channel where channel_id = %d limit 1",
        intval($item['uid'])
    );
    if ($c) {
        q("delete from dreport where dreport_xchan = '%s' and dreport_mid = '%s'",
            dbesc($c[0]['channel_hash']),
            dbesc($item['mid'])
        );
    }

    // The threadlistener interface does not support uid/channel_id, so
    // only remove threadlisteners when doing the second stage of a federated delete.

    if ($stage === DROPITEM_PHASE2) {
        ThreadListener::delete_by_target($item['mid']);
    }

    q("delete from notify where uid = %d and link = '%s'",
        intval($item['uid']),
        dbesc($item['mid'])
    );

    return true;
}

/**
 * @brief Return the first post date.
 *
 * @param int $uid
 * @param boolean $wall (optional) no longer used
 * @return string|boolean date string, otherwise false
 */
function first_post_date($uid, $wall = false) {

    $sql_extra = '';

    switch (App::$module) {
        case 'articles':
            $sql_extra .= " and item_type = 7 ";
            $item_normal = " and item.item_hidden = 0 and item.item_type = 7 and item.item_deleted = 0
                and item.item_unpublished = 0 and item.item_delayed = 0 and item.item_pending_remove = 0
                and item.item_blocked = 0 ";
            break;
        case 'channel':
            $sql_extra = " and item_wall = 1 ";
        default:
            $item_normal = item_normal();
            break;
    }

    $r = q("select id, created from item
        where uid = %d and id = parent $item_normal $sql_extra
        order by created asc limit 1",
        intval($uid)
    );

    if ($r) {
        return datetime_convert('UTC',date_default_timezone_get(),$r[0]['created'], 'Y-m-d');
    }

    return false;
}

/**
 * modified posted_dates() {below} to arrange the list in years, which we'll eventually
 * use to make a menu of years with collapsible sub-menus for the months instead of the
 * current flat list of all representative dates.
 *
 * @param int $uid
 * @param boolean $wall
 * @param string $mindate
 * @return array
 */
function list_post_dates($uid, $wall, $mindate) {

    $ret = [];

    $dnow = datetime_convert('',date_default_timezone_get(),'now','Y-m-d');

    if ($mindate) {
        $dthen = datetime_convert('',date_default_timezone_get(), $mindate);
    }
    else {
        $dthen = first_post_date($uid, $wall);
    }
    if (! $dthen) {
        return [];
    }

    // If it's near the end of a long month, backup to the 28th so that in
    // consecutive loops we'll always get a whole month difference.

    if (intval(substr($dnow,8)) > 28) {
        $dnow = substr($dnow,0,8) . '28';
    }
    if (intval(substr($dthen,8)) > 28) {
        $dthen = substr($dthen,0,8) . '28';
    }

    // Starting with the current month, get the first and last days of every
    // month down to and including the month of the first post

    while (substr($dnow, 0, 7) >= substr($dthen, 0, 7)) {
        $dyear = intval(substr($dnow,0,4));
        $dstart = substr($dnow,0,8) . '01';
        $dend = substr($dnow,0,8) . get_dim(intval($dnow),intval(substr($dnow,5)));
        $start_month = datetime_convert('','',$dstart,'Y-m-d');
        $end_month = datetime_convert('','',$dend,'Y-m-d');
        $str = day_translate(datetime_convert('','',$dnow,'F'));
        if (! $ret[$dyear]) {
            $ret[$dyear] = [];
        }
         $ret[$dyear][] =  [ $str, $end_month, $start_month ];
        $dnow = datetime_convert('','',$dnow . ' -1 month', 'Y-m-d');
    }

    return $ret;
}


function posted_dates($uid,$wall) {

    $dnow = datetime_convert('UTC',date_default_timezone_get(),'now','Y-m-d');

    $dthen = first_post_date($uid,$wall);

    if (! $dthen) {
        return [];
    }

    // If it's near the end of a long month, backup to the 28th so that in
    // consecutive loops we'll always get a whole month difference.

    if (intval(substr($dnow,8)) > 28) {
        $dnow = substr($dnow,0,8) . '28';
    }
    if (intval(substr($dthen,8)) > 28) {
        $dthen = substr($dthen,0,8) . '28';
    }

    $ret = [];

    // Starting with the current month, get the first and last days of every
    // month down to and including the month of the first post

    while (substr($dnow, 0, 7) >= substr($dthen, 0, 7)) {
        $dstart = substr($dnow,0,8) . '01';
        $dend = substr($dnow,0,8) . get_dim(intval($dnow),intval(substr($dnow,5)));
        $start_month = datetime_convert('','',$dstart,'Y-m-d');
        $end_month = datetime_convert('','',$dend,'Y-m-d');
        $str = day_translate(datetime_convert('','',$dnow,'F Y'));
         $ret[] = [$str,$end_month,$start_month];
        $dnow = datetime_convert('','',$dnow . ' -1 month', 'Y-m-d');
    }
    return $ret;
}

/**
 * @brief Extend an item array with the associated tags of the posts.
 *
 * @param array $items
 * @return array Return the provided $items array after extended the posts with tags
 */
function fetch_post_tags($items) {

    $tag_finder = [];
    if ($items) {
        foreach ($items as $item) {
            if (is_array($item)) {
                if (array_key_exists('item_id',$item)) {
                    if (! in_array($item['item_id'],$tag_finder)) {
                        $tag_finder[] = $item['item_id'];
                    }
                }
                else {
                    if (! in_array($item['id'],$tag_finder)) {
                        $tag_finder[] = $item['id'];
                    }
                }
            }
        }
    }

    $tag_finder_str = implode(', ', $tag_finder);

    if (strlen($tag_finder_str)) {
        $tags = q("select * from term where oid in ( %s ) and otype = %d",
            dbesc($tag_finder_str),
            intval(TERM_OBJ_POST)
        );
        $imeta = q("select * from iconfig where iid in ( %s )",
            dbesc($tag_finder_str)
        );
    }

    for ($x = 0; $x < count((array)$items); $x ++) {
        if ($tags) {
            foreach ($tags as $t) {
                if (array_key_exists('item_id',$items[$x])) {
                    if ($t['oid'] == $items[$x]['item_id']) {
                        if (! (isset($items[$x]['term']) && is_array($items[$x]['term']))) {
                            $items[$x]['term'] = [];
                        }
                        $items[$x]['term'][] = $t;
                    }
                }
                else {
                    if ($t['oid'] == $items[$x]['id']) {
                        if (! (isset($items[$x]['term']) && is_array($items[$x]['term']))) {
                            $items[$x]['term'] = [];
                        }
                        $items[$x]['term'][] = $t;
                    }
                }
            }
        }
        if ($imeta) {
            foreach ($imeta as $i) {
                if (array_key_exists('item_id',$items[$x])) {
                    if ($i['iid'] == $items[$x]['item_id']) {
                        if (! (isset($items[$x]['iconfig']) && is_array($items[$x]['iconfig']))) {
                            $items[$x]['iconfig'] = [];
                        }
                        $i['v'] = unserialise($i['v']);
                        $items[$x]['iconfig'][] = $i;
                    }
                }
                else {
                    if ($i['iid'] == $items[$x]['id']) {
                        if (! (isset($items[$x]['iconfig']) && is_array($items[$x]['iconfig']))) {
                            $items[$x]['iconfig'] = [];
                        }
                        $i['v'] = unserialise($i['v']);
                        $items[$x]['iconfig'][] = $i;
                    }
                }
            }
        }
    }

    return $items;
}


/**
 * @brief
 *
 * @param int $uid
 * @param string $observer_hash
 * @param array $arr
 * @return array
 */
function zot_feed($uid, $observer_hash, $arr) {

    $result = [];
    $mindate = null;
    $message_id = null;
    $wall = true;

    require_once('include/security.php');

    $encoding = ((array_key_exists('encoding',$arr)) ? $arr['encoding'] : 'zot');

    if(array_key_exists('mindate',$arr)) {
        $mindate = datetime_convert('UTC','UTC',$arr['mindate']);
    }

    if(array_key_exists('message_id',$arr)) {
        $message_id = $arr['message_id'];
    }

    if(array_key_exists('wall',$arr)) {
        $wall = intval($arr['wall']);
    }

    if(! $mindate)
        $mindate = NULL_DATE;

    $mindate = dbesc($mindate);

    logger('zot_feed: requested for uid ' . $uid . ' from observer ' . $observer_hash, LOGGER_DEBUG);
    if($message_id)
        logger('message_id: ' . $message_id,LOGGER_DEBUG);

    if(! perm_is_allowed($uid, $observer_hash, 'view_stream')) {
        logger('zot_feed: permission denied.');
        return $result;
    }

    if(! Channel::is_system($uid))
        $sql_extra = item_permissions_sql($uid,$observer_hash);

    $limit = " LIMIT 5000 ";

    if($mindate > NULL_DATE) {
        $sql_extra .= " and ( created > '$mindate' or changed > '$mindate' ) ";
    }

    if($message_id) {
        $sql_extra .= " and mid = '" . dbesc($message_id) . "' ";
        $limit = '';
    }

    if($wall) {
        $sql_extra .= " and item_wall = 1 ";
    }


    $items = [];

    $item_normal = item_normal();

    if(Channel::is_system($uid)) {

        $nonsys_uids = q("SELECT channel_id FROM channel WHERE channel_system = 0");
        $nonsys_uids_str = ids_to_querystr($nonsys_uids,'channel_id');

        $r = q("SELECT parent FROM item
            WHERE uid IN ( %s )
            AND item_private = 0
            $item_normal
            $sql_extra ORDER BY created ASC $limit",
            intval($nonsys_uids_str)
        );
    }
    else {
        $r = q("SELECT parent FROM item
            WHERE uid = %d
            $item_normal
            $sql_extra ORDER BY created ASC $limit",
            intval($uid)
        );
    }

    $parents = [];

    if($r) {
        foreach($r as $rv) {
            if(array_key_exists($rv['parent'],$parents))
                continue;
            $parents[$rv['parent']] = $rv;
            if(count($parents) > 200)
                break;
        }

        $parents_str = ids_to_querystr($parents,'parent');
        $sys_query = ((Channel::is_system($uid)) ? $sql_extra : '');
        $item_normal = item_normal();

        $items = q("SELECT item.*, item.id AS item_id FROM item
            WHERE item.parent IN ( %s ) $item_normal $sys_query ",
            dbesc($parents_str)
        );
    }

    if($items) {
        xchan_query($items);
        $items = fetch_post_tags($items);
        require_once('include/conversation.php');
        $items = conv_sort($items,'ascending');
    }
    else
        $items = [];

    logger('zot_feed: number items: ' . count($items),LOGGER_DEBUG);

    foreach($items as $item) {
        if($encoding === 'zot')
            $result[] = encode_item($item);
        elseif($encoding === 'activitystreams')
            $result[] = Activity::encode_activity($item, true, Activity::isContainer($item));
    }

    return $result;
}


function items_fetch($arr,$channel = null,$observer_hash = null,$client_mode = CLIENT_MODE_NORMAL,$module = 'stream') {

    $result = [ 'success' => false ];

    $uid = 0;
    $sql_extra = '';
    $sql_nets = '';
    $sql_options = '';
    $sql_extra2 = '';
    $sql_extra3 = '';
    $def_acl = '';

    $item_uids = ' true ';
    $item_normal = item_normal();

    if (isset($arr['uid']) && $arr['uid']) {
        $uid = $arr['uid'];
    }

    if ($channel) {
        $uid = $channel['channel_id'];
        $uidhash = $channel['channel_hash'];
        $item_uids = " item.uid = " . intval($uid) . " ";
    }

    if (! (isset($arr['include_follow']) && intval($arr['include_follow']))) {
        $item_normal .= " and not verb in ( 'Follow' , 'Ignore' ) ";
    }

    if (isset($arr['star']) && $arr['star']) {
        $sql_options .= " and item_starred = 1 ";
    }

    if (isset($arr['wall']) && $arr['wall']) {
        $sql_options .= " and item_wall = 1 ";
    }

    if (isset($arr['item_id']) && $arr['item_id']) {
        $sql_options .= " and parent = " . intval($arr['item_id']) . " ";
    }

    if (isset($arr['mid']) && $arr['mid']) {
        $sql_options .= " and parent_mid = '" . dbesc($arr['mid']) . "' ";
    }

    $sql_extra = " AND item.parent IN ( SELECT parent FROM item WHERE item_thread_top = 1 $sql_options $item_normal ) ";

    if (!empty($arr['since_id'])) {
        $sql_extra .= " and item.id > " . $arr['since_id'] . " ";
    }

    if (!empty($arr['cat'])) {
        $sql_extra .= protect_sprintf(term_query('item', $arr['cat'], TERM_CATEGORY));
    }

    if ($uid && !empty($arr['gid'])) {
        $r = q("SELECT * FROM pgrp WHERE id = %d AND uid = %d LIMIT 1",
            intval($arr['group']),
            intval($uid)
        );
        if (! $r) {
            $result['message']  = t('Access list not found.');
            return $result;
        }

        $contact_str = '';

        $contacts = AccessList::members($uid,$r[0]['id']);
        if ($contacts) {
            foreach ($contacts as $c) {
                if ($contact_str) {
                    $contact_str .= ',';
                }
                $contact_str .= "'" . $c['xchan'] . "'";
            }
        }
        else {
            $contact_str = ' 0 ';
            $result['message'] = t('Privacy group is empty.');
            return $result;
        }

        $sql_extra = " AND item.parent IN ( SELECT DISTINCT parent FROM item WHERE true $sql_options AND (( author_xchan IN ( $contact_str ) OR owner_xchan in ( $contact_str)) or allow_gid like '" . protect_sprintf('%<' . dbesc($r[0]['hash']) . '>%') . "' ) and id = parent $item_normal ) ";

        $x = AccessList::rec_byhash($uid,$r[0]['hash']);
        $result['headline'] = sprintf( t('Access list: %s'),$x['gname']);
    }
    elseif (isset($arr['cid']) && $arr['cid'] && $uid) {

        $r = q("SELECT abook.*, xchan.* from abook left join xchan on abook_xchan = xchan_hash where abook_id = %d and abook_channel = %d and abook_blocked = 0 limit 1",
            intval($arr['cid']),
            intval(local_channel())
        );
        if ($r) {
            $sql_extra = " AND item.parent IN ( SELECT DISTINCT parent FROM item WHERE true $sql_options AND uid = " . intval($arr['uid']) . " AND ( author_xchan = '" . dbesc($r[0]['abook_xchan']) . "' or owner_xchan = '" . dbesc($r[0]['abook_xchan']) . "' ) $item_normal ) ";
            $result['headline'] = sprintf( t('Connection: %s'),$r[0]['xchan_name']);
        }
        else {
            $result['message'] = t('Channel not found.');
            return $result;
        }
    }

    if ($channel && intval($arr['compat']) === 1) {
        $sql_extra = " AND author_xchan = '" . $channel['channel_hash'] . "' and item_private = 0 $item_normal ";
    }

    if ($arr['datequery']) {
        $sql_extra3 .= protect_sprintf(sprintf(" AND item.created <= '%s' ", dbesc(datetime_convert('UTC','UTC',$arr['datequery']))));
    }
    if ($arr['datequery2']) {
        $sql_extra3 .= protect_sprintf(sprintf(" AND item.created >= '%s' ", dbesc(datetime_convert('UTC','UTC',$arr['datequery2']))));
    }

    if ($arr['search']) {
        if (str_starts_with($arr['search'], '#')) {
            $sql_extra .= term_query('item',substr($arr['search'],1),TERM_HASHTAG,TERM_COMMUNITYTAG);

        }
        else {
            $sql_extra .= sprintf(" AND item.body like '%s' ",
                dbesc(protect_sprintf('%' . $arr['search'] . '%'))
            );
        }
    }

    if (isset($arr['file']) && strlen($arr['file'])) {
        $sql_extra .= term_query('item',$arr['file'],TERM_FILE);
    }

    if (isset($arr['conv']) && $arr['conv'] && $channel) {
        $sql_extra .= sprintf(" AND parent IN (SELECT distinct parent from item where ( author_xchan like '%s' or item_mentionsme = 1 )) ",
            dbesc(protect_sprintf($uidhash))
        );
    }

    if (($client_mode & CLIENT_MODE_UPDATE) && (! ($client_mode & CLIENT_MODE_LOAD))) {
        // only setup pagination on initial page view
        $pager_sql = '';
    }
    else {
        if (! (isset($arr['total']) && $arr['total']) ) {
            $itemspage = ((isset($arr['records']))  ? $arr['records'] : 0);
            if (! $itemspage) {
                $itemspage = (($channel) ? get_pconfig($uid,'system','itemspage') : 20);
                App::set_pager_itemspage(((intval($itemspage)) ? $itemspage : 20));
                $pager_sql = sprintf(" LIMIT %d OFFSET %d ", intval(App::$pager['itemspage']), intval(App::$pager['start']));
            }
        }
    }

    if (isset($arr['start']) && isset($arr['records'])) {
        $pager_sql = sprintf(" LIMIT %d OFFSET %d ", intval($arr['records']), intval($arr['start']));
    }

    if (array_key_exists('cmin',$arr) || array_key_exists('cmax',$arr)) {
        if (($arr['cmin'] != 0) || ($arr['cmax'] != 99)) {

            // Not everybody who shows up in the stream will be in your address book.
            // By default, those that aren't are assumed to have closeness = 99; but this isn't
            // recorded anywhere. So if cmax is 99, we'll open the search up to anybody in
            // the stream with a NULL address book entry.

            $sql_nets .= " AND ";

            if ($arr['cmax'] == 99)
                $sql_nets .= " ( ";

            $sql_nets .= "( abook.abook_closeness >= " . intval($arr['cmin']) . " ";
            $sql_nets .= " AND abook.abook_closeness <= " . intval($arr['cmax']) . " ) ";

            if ($arr['cmax'] == 99)
                $sql_nets .= " OR abook.abook_closeness IS NULL ) ";
        }
    }

    $simple_update = (($client_mode & CLIENT_MODE_UPDATE) ? " and item.item_unseen = 1 " : '');
    if ($client_mode & CLIENT_MODE_LOAD) {
        $simple_update = '';
    }

    $sql_extra .= item_permissions_sql($channel['channel_id'],$observer_hash);


    if (isset($arr['pages']) && $arr['pages']) {
        $item_restrict = " AND item_type = " . ITEM_TYPE_WEBPAGE . " ";
    }
    else {
        $item_restrict = " AND item_type = 0 ";
    }

    if (isset($arr['item_type']) && $arr['item_type'] === '*') {
        $item_restrict = '';
    }

    if (((isset($arr['compat']) && $arr['compat']) || ((isset($arr['nouveau']) && $arr['nouveau']) && ($client_mode & CLIENT_MODE_LOAD))) && $channel) {

        // "New Item View" - show all items unthreaded in reverse created date order

        if (isset($arr['total']) && $arr['total']) {
            $items = q("SELECT count(item.id) AS total FROM item
                WHERE $item_uids $item_restrict
                $simple_update
                $sql_extra $sql_nets $sql_extra3"
            );
            if ($items) {
                return intval($items[0]['total']);
            }
            return 0;
        }

        $items = q("SELECT item.*, item.id AS item_id FROM item
                WHERE $item_uids $item_restrict
                $simple_update
                $sql_extra $sql_nets $sql_extra3
                ORDER BY item.received DESC $pager_sql"
        );


        xchan_query($items);
        $items = fetch_post_tags($items);

    }
    else {

        // Normal conversation view

        if (isset($arr['order']) && $arr['order'] === 'post') {
            $ordering = "created";
        }
        else {
            $ordering = "commented";
        }

        if (($client_mode & CLIENT_MODE_LOAD) || ($client_mode == CLIENT_MODE_NORMAL)) {

            // Fetch a page full of parent items for this page

            $r = q("SELECT distinct item.id AS item_id, item.$ordering FROM item
                left join abook on item.author_xchan = abook.abook_xchan
                WHERE $item_uids $item_restrict
                AND item.parent = item.id
                and (abook.abook_blocked = 0 or abook.abook_flags is null)
                $sql_extra3 $sql_extra $sql_nets
                ORDER BY item.$ordering DESC $pager_sql "
            );
        }
        else {
            // update
            $r = q("SELECT item.parent AS item_id FROM item
                left join abook on item.author_xchan = abook.abook_xchan
                WHERE $item_uids $item_restrict $simple_update
                and (abook.abook_blocked = 0 or abook.abook_flags is null)
                $sql_extra3 $sql_extra $sql_nets "
            );
        }

        // Then fetch all the children of the parents that are on this page

        if ($r) {

            $parents_str = ids_to_querystr($r,'item_id');

            if (isset($arr['top']) && $arr['top']) {
                $sql_extra = ' and id = parent ' . $sql_extra;
            }
            $items = q("SELECT item.*, item.id AS item_id FROM item
                WHERE $item_uids $item_restrict
                AND item.parent IN ( %s )
                $sql_extra ",
                dbesc($parents_str ?: '0')
            );

            xchan_query($items);
            $items = fetch_post_tags($items);

            require_once('include/conversation.php');
            $items = conv_sort($items,$ordering);

        }
        else {
            $items = [];
        }
    }
    return $items;
}

function webpage_to_namespace($webpage) {

    if ($webpage == ITEM_TYPE_WEBPAGE)
        $page_type = 'WEBPAGE';
    elseif ($webpage == ITEM_TYPE_BLOCK)
        $page_type = 'BUILDBLOCK';
    elseif ($webpage == ITEM_TYPE_PDL)
        $page_type = 'PDL';
    elseif ($webpage == ITEM_TYPE_CARD)
        $page_type = 'CARD';
    elseif ($webpage == ITEM_TYPE_ARTICLE)
        $page_type = 'ARTICLE';
    elseif ($webpage == ITEM_TYPE_DOC)
        $page_type = 'docfile';
    else
        $page_type = 'unknown';

    return $page_type;
}


function update_remote_id($channel,$post_id,$webpage,$pagetitle,$namespace,$remote_id,$mid) {

    if (! $post_id) {
        return;
    }

    $page_type = webpage_to_namespace($webpage);

    if ($page_type == 'unknown' && $namespace && $remote_id) {
        $page_type = $namespace;
        $pagetitle = $remote_id;
    }
    else {
        $page_type = '';
    }

    if ($page_type) {

        // store page info as an alternate message_id so we can access it via
        //    https://sitename/page/$channelname/$pagetitle
        // if no pagetitle was given or it couldn't be transliterated into a url, use the first
        // sixteen bytes of the mid - which makes the link portable and not quite as daunting
        // as the entire mid. If it were the post_id the link would be less portable.

        $post_id = intval($post_id);
        IConfig::Set(
            $post_id,
            'system',
            $page_type,
            ($pagetitle) ?: substr($mid,0,16),
            false
        );
    }
}


/**
 * @brief Change access control for item with message_id $mid and channel_id $uid.
 *
 * @param string $xchan_hash
 * @param string $mid
 * @param int $uid
 */
function item_add_cid($xchan_hash, $mid, $uid) {
    $r = q("select id from item where mid = '%s' and uid = %d and allow_cid like '%s'",
        dbesc($mid),
        intval($uid),
        dbesc('<' . $xchan_hash . '>')
    );
    if (! $r) {
        $r = q("update item set allow_cid = concat(allow_cid,'%s') where mid = '%s' and uid = %d",
            dbesc('<' . $xchan_hash . '>'),
            dbesc($mid),
            intval($uid)
        );
    }
}

function item_remove_cid($xchan_hash,$mid,$uid) {
    $r = q("select allow_cid from item where mid = '%s' and uid = %d and allow_cid like '%s'",
        dbesc($mid),
        intval($uid),
        dbesc('<' . $xchan_hash . '>')
    );
    if ($r) {
        $x = q("update item set allow_cid = '%s' where mid = '%s' and uid = %d",
            dbesc(str_replace('<' . $xchan_hash . '>','',$r[0]['allow_cid'])),
            dbesc($mid),
            intval($uid)
        );
    }
}

// Set item permissions based on results obtained from linkify_tags()
function set_linkified_perms($linkified, &$str_contact_allow, &$str_group_allow, $profile_uid, $parent_item, &$private) {
    $first_access_tag = true;

    foreach($linkified as $x) {
        $access_tag = $x['success']['access_tag'];
        if(($access_tag) && (! $parent_item)) {
            logger('access_tag: ' . print_r($access_tag,true), LOGGER_DATA);
            if ($first_access_tag && (! get_pconfig($profile_uid,'system','no_private_mention_acl_override'))) {

                // This is a tough call, hence configurable. The issue is that one can type in a @!privacy mention
                // and also have a default ACL (perhaps from viewing a collection) and could be suprised that the
                // privacy mention wasn't the only recipient. So the default is to wipe out the existing ACL if a
                // private mention is found. This can be over-ridden if you wish private mentions to be in
                // addition to the current ACL settings.

                $str_contact_allow = '';
                $str_group_allow = '';
                $first_access_tag = false;
            }
            if(str_starts_with($access_tag, 'cid:')) {
                $str_contact_allow .= '<' . substr($access_tag,4) . '>';
                $access_tag = '';
                $private = 2;
            }
            elseif(str_starts_with($access_tag, 'gid:')) {
                $str_group_allow .= '<' . substr($access_tag,4) . '>';
                $access_tag = '';
                $private = 2;
            }
        }
    }
}

/**
 * We can't trust ITEM_ORIGIN to tell us if this is a local comment
 * which needs to be relayed, because it was misconfigured at one point for several
 * months and set for some remote items (in alternate delivery chains). This could
 * cause looping, so use this hackish but accurate method.
 *
 * @param array $item
 * @return boolean
 */
function comment_local_origin($item) {
    if(stripos($item['mid'], App::get_hostname()) && ($item['parent'] != $item['id']))
        return true;

    return false;
}

function send_profile_photo_activity($channel,$photo,$profile) {

    // for now only create activities for the default profile

    if (! (isset($profile) && isset($profile['is_default']) && intval($profile['is_default']))) {
        return;
    }

    $arr = [];
    $arr['item_thread_top'] = 1;
    $arr['item_origin'] = 1;
    $arr['item_wall'] = 1;
    $arr['obj_type'] = ACTIVITY_OBJ_NOTE;
    $arr['verb'] = ACTIVITY_CREATE;
    $arr['uuid'] = new_uuid();
    $arr['mid'] = z_root() . '/item/' . $arr['uuid'];

    if(stripos($profile['gender'],t('female')) !== false)
        $t = t('%1$s updated her %2$s');
    elseif(stripos($profile['gender'],t('male')) !== false)
        $t = t('%1$s updated his %2$s');
    else
        $t = t('%1$s updated their %2$s');

    $ptext = '[zrl=' . z_root() . '/photos/' . $channel['channel_address'] . '/image/' . $photo['resource_id'] . ']' . t('profile photo') . '[/zrl]';

    $ltext = '[zrl=' . z_root() . '/profile/' . $channel['channel_address'] . ']' . '[zmg=150x150]' . z_root() . '/photo/' . $photo['resource_id'] . '-4[/zmg][/zrl]';

    $arr['body'] = sprintf($t,$channel['channel_name'],$ptext) . "\n\n" . $ltext;


    $arr['obj'] = [
        'type'      => ACTIVITY_OBJ_NOTE,
        'published' => datetime_convert('UTC', 'UTC', 'now', ATOM_TIME),
        'updated'   => datetime_convert('UTC', 'UTC', 'now', ATOM_TIME),
        'id'        => $arr['mid'],
        'url'       => [ 'type' => 'Link', 'mediaType' => $photo['mimetype'], 'href' => z_root() . '/photo/profile/l/' . $channel['channel_id'] ],
        'source'    => [ 'content' => $arr['body'], 'mediaType' => 'text/x-multicode' ],
        'content'   => bbcode($arr['body']),
        'actor'     => Activity::encode_person($channel,false),
    ];

    $acl = new AccessControl($channel);
    $x = $acl->get();
    $arr['allow_cid'] = $x['allow_cid'];

    $arr['allow_gid'] = $x['allow_gid'];
    $arr['deny_cid'] = $x['deny_cid'];
    $arr['deny_gid'] = $x['deny_gid'];

    $arr['uid'] = $channel['channel_id'];
    $arr['aid'] = $channel['channel_account_id'];

    $arr['owner_xchan'] = $channel['channel_hash'];
    $arr['author_xchan'] = $channel['channel_hash'];

    post_activity_item($arr);
}


function sync_an_item($channel_id,$item_id) {

    $r = q("select * from item where id = %d",
        intval($item_id)
    );
    if($r) {
        if (intval($r[0]['parent']) !== intval($r[0]['id'])) {
            // sync the parent also. This prevents mis-deliveries from sync packets arriving out of order.
            $y = q("select * from item where id = %d",
                intval($r[0]['parent'])
            );
            if ($y) {
                $r = array_merge($y,$r);
            }
        }
        $encoded = [];
        xchan_query($r);
        $sync_items = fetch_post_tags($r);
        if ($sync_items) {
            foreach ($sync_items as $i) {
                $encoded[] = encode_item($i,true);
            }
        }
        Libsync::build_sync_packet($channel_id, ['item' => $encoded]);
    }
}

function list_attached_local_files($body) {

    $files = [];
    $match = [];

    // match img and zmg image links
    if (preg_match_all("/\[[zi]mg(.*?)](.*?)\[\/[zi]mg]/",$body,$match)) {
        $images = $match[2];
        if ($images) {
            foreach ($images as $image) {
                if (! stristr($image,z_root() . '/photo/')) {
                    continue;
                }
                $image_uri = substr($image,strrpos($image,'/') + 1);
                if (str_contains($image_uri, '-')) {
                    $image_uri = substr($image_uri,0, strrpos($image_uri,'-'));
                }
                if (str_contains($image_uri, '.')) {
                    $image_uri = substr($image_uri,0, strpos($image_uri,'.'));
                }
                if ($image_uri) {
                    $files[] = $image_uri;
                }
            }
        }
    }
    if (preg_match_all("/\[attachment](.*?)\[\/attachment]/",$body,$match)) {
        $attaches = $match[1];
        if ($attaches) {
            foreach ($attaches as $attach) {
                $hash = substr($attach,0,strpos($attach,','));
                if ($hash) {
                    $files[] = $hash;
                }
            }
        }
    }

    return $files;
}

function fix_attached_permissions($uid,$body,$str_contact_allow,$str_group_allow,$str_contact_deny,$str_group_deny,$token = EMPTY_STR) {

    $files = list_attached_local_files($body);
    if (! $files) {
        return;
    }

    foreach ($files as $file) {
        $attach_q = q("select id, hash, flags, is_photo, allow_cid, allow_gid, deny_cid, deny_gid from attach where hash = '%s' and uid = %d",
            dbesc($file),
            intval($uid)
        );

        if (! $attach_q) {
            continue;
        }

        $attach = array_shift($attach_q);

        $new_public = !(($str_contact_allow || $str_group_allow || $str_contact_deny || $str_group_deny));
        $existing_public = !(($attach['allow_cid'] || $attach['allow_gid'] || $attach['deny_cid'] || $attach['deny_gid']));

        if ($existing_public) {
            // permissions have already been fixed and they are public. There's nothing for us to do.
            continue;
        }

        // if flags & 1, the attachment was uploaded directly into a post and needs to have permissions corrected
        // or - if it is a private file and a new token was generated, we'll need to add the token to the ACL.

        if (((intval($attach['flags']) & 1) !== 1) && (! $token)) {
            continue;
        }

        $item_private = 0;

        if ($new_public === false) {

            $item_private = (($str_group_allow || ($str_contact_allow && substr_count($str_contact_allow,'<') > 2)) ? 1 : 2);

            // preserve any existing tokens that may have been set for this file
            $token_matches = null;
            if (preg_match_all('/<token:(.*?)>/',$attach['allow_cid'],$token_matches, PREG_SET_ORDER)) {
                foreach ($token_matches as $m) {
                    $tok = '<token:' . $m[1] . '>';
                    if (!str_contains($str_contact_allow, $tok)) {
                        $str_contact_allow .= $tok;
                    }
                }
            }
            if ($token) {
                $str_contact_allow .= '<token:' . $token . '>';
            }
        }

        q("update attach SET allow_cid = '%s', allow_gid = '%s', deny_cid = '%s', deny_gid = '%s', flags = 0
            WHERE id = %d AND uid = %d",
            dbesc($str_contact_allow),
            dbesc($str_group_allow),
            dbesc($str_contact_deny),
            dbesc($str_group_deny),
            intval($attach['id']),
            intval($uid)
        );

        if ($attach['is_photo']) {
            $r = q("UPDATE photo SET allow_cid = '%s', allow_gid = '%s', deny_cid = '%s', deny_gid = '%s'
                WHERE resource_id = '%s' AND uid = %d ",
                dbesc($str_contact_allow),
                dbesc($str_group_allow),
                dbesc($str_contact_deny),
                dbesc($str_group_deny),
                dbesc($file),
                intval($uid)
            );

            $r = q("UPDATE item SET allow_cid = '%s', allow_gid = '%s', deny_cid = '%s', deny_gid = '%s', item_private = %d
                WHERE resource_id = '%s' AND 'resource_type' = 'photo'  AND uid = %d",
                dbesc($str_contact_allow),
                dbesc($str_group_allow),
                dbesc($str_contact_deny),
                dbesc($str_group_deny),
                intval($item_private),
                dbesc($file),
                intval($uid)
            );
        }
    }
}


function item_create_edit_activity($post) {
    // obsolete and not maintained, left in case it is ever needed again
    if((! $post) || (! $post['item']) || ($post['item']['item_type'] != ITEM_TYPE_POST))
        return;

    $update_item = $post['item'];

    $new_item = $update_item;

    $author = q("select * from xchan where xchan_hash = '%s' limit 1",
        dbesc($new_item['author_xchan'])
    );
    if($author)
        $item_author = $author[0];


    $new_item['id'] = 0;
    $new_item['parent'] = 0;
    $new_item['uuid'] = new_uuid();
    $new_item['mid'] = z_root() . '/item/' . $new_item['uuid'];

    $new_item['body'] = sprintf( t('[Edited %s]'), (($update_item['item_thread_top']) ? t('Post','edit_activity') : t('Comment','edit_activity')));

    $new_item['body'] .= "\n\n";
    $new_item['body'] .= $update_item['body'];

    $new_item['sig'] = '';

    $new_item['verb'] = ACTIVITY_UPDATE;
    $new_item['item_thread_top'] = 0;
    $new_item['created'] = $new_item['edited'] = datetime_convert();
    $new_item['obj_type'] = (($update_item['item_thread_top']) ? ACTIVITY_OBJ_NOTE : ACTIVITY_OBJ_COMMENT);
    $new_item['obj'] = json_encode([
        'type'    => $new_item['obj_type'],
        'id'      => $update_item['mid'],
        'parent'  => $update_item['parent_mid'],
        'link'    => [['rel' => 'alternate','type' => 'text/html', 'href' => $update_item['plink']]],
        'title'   => $update_item['title'],
        'content' => $update_item['body'],
        'created' => $update_item['created'],
        'edited'  => $update_item['edited'],
        'author'  => [
            'name'     => $item_author['xchan_name'],
            'address'  => $item_author['xchan_addr'],
            'guid'     => $item_author['xchan_guid'],
            'guid_sig' => $item_author['xchan_guid_sig'],
            'link'     => [
                ['rel' => 'alternate', 'type' => 'text/html', 'href' => $item_author['xchan_url']],
                ['rel' => 'photo', 'type' => $item_author['xchan_photo_mimetype'], 'href' => $item_author['xchan_photo_m']]],
        ],
    ],JSON_UNESCAPED_SLASHES);


    $x = post_activity_item($new_item);

    $post_id = $x['id'];
    if($post_id) {
        $r = q("select * from item where id = %d",
                    intval($post_id)
        );
        if($r) {
            xchan_query($r);
            $sync_item = fetch_post_tags($r);
            Libsync::build_sync_packet($new_item['uid'], ['item' => [encode_item($sync_item[0],true)]]);
        }
    }

    Run::Summon([ 'Notifier', 'edit_activity', $post_id ]);
}

/**
 * @brief copies an entire conversation from the pubstream to this channel's stream
 * which will allow you to interact with it.
 */


function copy_of_pubitem($channel,$mid) {

    $result = null;
    $syschan = Channel::get_system();

    logger('copy_of_pubitem: ' . $channel['channel_id'] . ' mid: ' . $mid);

    $r = q("select * from item where mid = '%s' and uid = %d limit 1",
        dbesc($mid),
        intval($channel['channel_id'])
    );

    if ($r) {
        logger('exists');
        $item = fetch_post_tags($r);
        return array_shift($item);
    }

    // this query is used for the global public stream
    $r = q("select * from item where parent_mid = ( select parent_mid from item where mid = '%s' and uid = %d ) order by id ",
        dbesc($mid),
        intval($syschan['channel_id'])
    );

    // if that failed, try to find entries that would have been posted in the local public stream
    if (! $r) {
        $r = q("select * from item where parent_mid = ( select distinct (parent_mid) from item where mid = '%s' and item_wall = 1 and item_private = 0 ) order by id ",
            dbesc($mid),
            intval($syschan['channel_id'])
        );
    }

    if ($r) {
        $items = fetch_post_tags($r);
        foreach ($items as $rv) {
            $d = q("select id from item where mid = '%s' and uid = %d limit 1",
                dbesc($rv['mid']),
                intval($channel['channel_id'])
            );
            if ($d) {
                logger('mid: ' . $rv['mid'] . ' already copied. Continuing.');
                continue;
            }

            unset($rv['id']);
            unset($rv['parent']);
            $rv['aid'] = $channel['channel_account_id'];
            $rv['uid'] = $channel['channel_id'];
            $rv['item_wall'] = 0;
            $rv['item_origin'] = 0;

            $x = item_store($rv);
            if ($x['item_id'] && $x['item']['mid'] === $mid) {
                $result = $x['item'];
                sync_an_item($channel['channel_id'],$x['item_id']);
            }

        }
    }
    else {
        logger('copy query failed.');
    }
    return $result;
}

function reverse_activity_mid($string)
{
    return str_replace(z_root() . '/activity/', z_root() . '/item/', $string);
}

function set_activity_mid($string)
{
    return str_replace(z_root() . '/item/', z_root() . '/activity/', $string);
}