<?php

use Code\Lib\Config;
use Code\Lib\Libzot;
use Code\Lib\Time;
use Code\Lib\Zotfinger;
use Code\Lib\Webfinger;
use Code\Lib\Channel;
use Code\Lib\Activity;
use Code\Lib\ActivityPub;
use Code\Lib\Queue;
use Code\Lib\System;
use Code\Lib\JcsEddsa2022;
use Code\Lib\Addon;
use Code\Lib\Url;
use Code\Web\HTTPSig;
use Code\Daemon\Run;
use Code\Extend\Hook;
use Code\Storage\Stdio;

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;
use PHPMailer\PHPMailer\Exception;

/**
 * @file include/network.php
 * @brief Network related functions.
 */

function json_return_and_die($x, $content_type = 'application/json', $debug = false)
{
    header("Content-type: $content_type");
    header('Cache-control: public');
    header_remove('Pragma');

    if ($debug) {
        logger('returned_json: ' . json_encode($x, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES), LOGGER_DATA);
    }
    echo json_encode($x);
    killme();
}

function as_return_and_die($obj, $channel, $contextType = null, $signObject = true)
{

    if (! is_array($obj)) {
        killme();
    }

    $data = array_merge(Activity::ap_context($contextType), $obj);


    $headers = [];
    $headers['Content-Type'] = 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"' ;
    header('Cache-control: public');
    header_remove('Pragma');
    
    if ($signObject) {
        $data['proof'] = (new JcsEddsa2022)->sign($data, $channel);
    }
    $json = json_encode($data, JSON_UNESCAPED_SLASHES);
    logger('data: ' . jindent($json), LOGGER_DATA);
    $headers['Date'] = Time::convert('UTC', 'UTC', 'now', 'D, d M Y H:i:s \\G\\M\\T');
    $headers['Digest'] = HTTPSig::generate_digest_header($json);
    $headers['(request-target)'] = strtolower($_SERVER['REQUEST_METHOD']) . ' ' . (App::$originalRequest ?? $_SERVER['REQUEST_URI']);

    $h = HTTPSig::create_sig($headers, $channel['channel_prvkey'], Channel::keyId($channel));
    HTTPSig::set_headers($h);

    echo $json;
    killme();
}


/**
 * @brief Send HTTP status header.
 *
 * @param int $val
 *    integer HTTP status result value
 * @param string $msg
 *    optional message
 */
function http_status($val, $msg = '', $log = true)
{
    if ($val >= 400) {
        $msg = (($msg) ?: 'Error');
    }
    if ($val >= 200 && $val < 300) {
        $msg = (($msg) ?: 'OK');
    }

    if ($log) {
        logger(App::$query_string . ':' . $val . ' ' . $msg);
    }
    if (isset($_SERVER['SERVER_PROTOCOL'])) {
        header($_SERVER['SERVER_PROTOCOL'] . ' ' . $val . ' ' . $msg);
    }
}


/**
 * @brief Send HTTP status header and exit.
 *
 * @param int $val
 *    integer HTTP status result value
 * @param string $msg
 *    optional message
 * @return void does not return, process is terminated
 */
function http_status_exit($val, $msg = '', $log = true)
{
    http_status($val, $msg, $log);
    killme();
}

/*
 *
 * Takes the output of parse_url and builds a URL from it
 *
 */

function unparse_url($parsed_url)
{
    $scheme   = isset($parsed_url['scheme']) ? $parsed_url['scheme'] . '://' : '';
    $host     = isset($parsed_url['host']) ? $parsed_url['host'] : '';
    $port     = ((isset($parsed_url['port']) && intval($parsed_url['port'])) ? ':' . intval($parsed_url['port']) : '');
    $user     = isset($parsed_url['user']) ? $parsed_url['user'] : '';
    $pass     = isset($parsed_url['pass']) ? ':' . $parsed_url['pass']  : '';
    $pass     = ($user || $pass) ? "$pass@" : '';
    $path     = isset($parsed_url['path']) ? $parsed_url['path'] : '';
    $query    = isset($parsed_url['query']) ? '?' . $parsed_url['query'] : '';
    $fragment = isset($parsed_url['fragment']) ? '#' . $parsed_url['fragment'] : '';
    return "$scheme$user$pass$host$port$path$query$fragment";
}


/**
 * @brief Convert an XML document to a normalised, case-corrected array used by webfinger.
 *
 * @param string|array|SimpleXMLElement $xml_element
 * @param[in,out] int $recursion_depth
 * @return NULL|string|array
 */
function convert_xml_element_to_array($xml_element, &$recursion_depth = 0)
{

    // If we're getting too deep, bail out
    if ($recursion_depth > 512) {
        return null;
    }

    if (
        !is_string($xml_element) &&
            !is_array($xml_element) &&
            (get_class($xml_element) == 'SimpleXMLElement')
    ) {
        $xml_element_copy = $xml_element;
        $xml_element = get_object_vars($xml_element);
    }

    if (is_array($xml_element)) {
        $result_array = [];
        if (count($xml_element) <= 0) {
            return (trim(strval($xml_element_copy)));
        }

        foreach ($xml_element as $key => $value) {
            $recursion_depth++;
            $result_array[strtolower($key)] =
                convert_xml_element_to_array($value, $recursion_depth);
            $recursion_depth--;
        }
        if ($recursion_depth == 0) {
            $temp_array = $result_array;
            $result_array = [
                strtolower($xml_element_copy->getName()) => $temp_array,
            ];
        }

        return ($result_array);
    } else {
        return (trim(strval($xml_element)));
    }
}


function z_dns_check($h, $check_mx = 0)
{

    // dns_get_record() has issues on some platforms
    // so allow somebody to ignore it completely
    // Use config values from memory as this can be called during setup
    // before a database or even any config structure exists.

    if (is_array(App::$config) && array_path_exists('system/do_not_check_dns', App::$config) && App::$config['system']['do_not_check_dns']) {
        return true;
    }

    // This will match either Windows or Mac ('Darwin')
    if (stripos(PHP_OS, 'win') !== false) {
        return true;
    }

    // BSD variants have dns_get_record() but it only works reliably without any options
    if (stripos(PHP_OS, 'bsd') !== false) {
        return @dns_get_record($h) || filter_var($h, FILTER_VALIDATE_IP);
    }

    // Otherwise we will assume dns_get_record() works as documented

    $opts = DNS_A + DNS_CNAME + DNS_AAAA;
    if ($check_mx) {
        $opts += DNS_MX;
    }

    return @dns_get_record($h, $opts) || filter_var($h, FILTER_VALIDATE_IP);
}

/**
 * @brief Validates a given URL.
 *
 * Take a URL from the wild, prepend http:// if necessary and check DNS to see
 * if it's real (or check if is a valid IP address).
 *
 * @see z_dns_check()
 *
 * @param[in,out] string $url URL to check
 * @return bool Return true if it's OK, false if something is wrong with it
 */
function validate_url(&$url)
{

    // no naked subdomains (allow localhost for tests)
    if (!str_contains($url, '.') && !str_contains($url, '/localhost/')) {
        return false;
    }

    if (!str_starts_with($url, 'http')) {
        $url = 'http://' . $url;
    }

    $h = @parse_url($url);

    if (($h) && z_dns_check($h['host'])) {
        return true;
    }

    return false;
}

/**
 * @brief Checks that email is an actual resolvable internet address.
 *
 * @param string $addr
 * @return bool
 */
function validate_email($addr)
{

    if (Config::Get('system', 'disable_email_validation')) {
        return true;
    }

    if (! strpos($addr, '@')) {
        return false;
    }

    $h = substr($addr, strpos($addr, '@') + 1);

    if (($h) && z_dns_check($h, true)) {
        return true;
    }

    return false;
}

/**
 * @brief Check if email address is allowed to register here.
 *
 * Compare against our list (wildcards allowed).
 *
 * @param string $email
 * @return bool Returns false if not allowed, true if allowed or if allowed list is
 * not configured.
 */
function allowed_email($email)
{

    $domain = strtolower(substr($email, strpos($email, '@') + 1));
    if (! $domain) {
        return false;
    }

    $str_allowed = Config::Get('system', 'allowed_email');
    $str_not_allowed = Config::Get('system', 'not_allowed_email');

    if (! $str_allowed && ! $str_not_allowed) {
        return true;
    }

    $return = false;
    $found_allowed = false;
    $found_not_allowed = false;

    $fnmatch = function_exists('fnmatch');

    $allowed = explode(',', $str_allowed);

    if (count($allowed)) {
        foreach ($allowed as $a) {
            $pat = strtolower(trim($a));
            if (($fnmatch && fnmatch($pat, $email)) || ($pat == $domain)) {
                $found_allowed = true;
                break;
            }
        }
    }

    $not_allowed = explode(',', $str_not_allowed);

    if (count($not_allowed)) {
        foreach ($not_allowed as $na) {
            $pat = strtolower(trim($na));
            if (($fnmatch && fnmatch($pat, $email)) || ($pat == $domain)) {
                $found_not_allowed = true;
                break;
            }
        }
    }

    if ($found_allowed) {
        $return = true;
    } elseif (!$str_allowed && !$found_not_allowed) {
        $return = true;
    }

    return $return;
}

/**
 * @brief Check if ip address is allowed to register here.
 *
 * Compare against our list (wildcards allowed).
 *
 * @param string $ip
 * @return bool Returns false if not allowed, true if allowed or if allowed list is
 * not configured.
 */
function allowed_ip($ip)
{


    $str_allowed = Config::Get('system', 'allowed_register_ip');
    $str_not_allowed = Config::Get('system', 'not_allowed_register_ip');

    if (! $str_allowed && ! $str_not_allowed) {
        return true;
    }

    if (!$ip) {
        return true;
    }

    $return = false;
    $found_allowed = false;
    $found_not_allowed = false;

    $fnmatch = function_exists('fnmatch');

    $allowed = explode(',', $str_allowed);

    if (count($allowed)) {
        foreach ($allowed as $a) {
            $pat = strtolower(trim($a));
            if ($fnmatch && fnmatch($pat, $ip)) {
                $found_allowed = true;
                break;
            }
        }
    }

    $not_allowed = explode(',', $str_not_allowed);

    if (count($not_allowed)) {
        foreach ($not_allowed as $na) {
            $pat = strtolower(trim($na));
            if ($fnmatch && fnmatch($pat, $ip)) {
                $found_not_allowed = true;
                break;
            }
        }
    }

    if ($found_allowed) {
        $return = true;
    } elseif (!$str_allowed && !$found_not_allowed) {
        $return = true;
    }

    return $return;
}


function parse_xml_string($s, $strict = true)
{
    if ($strict) {
        if (!str_contains($s, '<?xml')) {
            return false;
        }

        $s2 = substr($s, strpos($s, '<?xml'));
    } else {
        $s2 = $s;
    }

    libxml_use_internal_errors(true);


    $x = @simplexml_load_string($s2);
    if ($x === false) {
        logger('libxml: parse: error: ' . $s2, LOGGER_DATA);
        foreach (libxml_get_errors() as $err) {
            logger('libxml: parse: ' . $err->code . ' at ' . $err->line
                . ':' . $err->column . ' : ' . $err->message, LOGGER_DATA);
        }
        libxml_clear_errors();
    }

    return $x;
}


function sxml2array($xmlObject, $out = [])
{
    foreach ((array) $xmlObject as $index => $node) {
        $out[$index] = ( is_object($node) ) ? sxml2array($node) : $node;
    }
    return $out;
}

/**
 * @brief xml2[] will convert the given XML text to an array in the XML structure.
 *
 * Link: http://www.bin-co.com/php/scripts/xml2array/
 * Portions significantly re-written by mike@macgirvin.com
 * (namespaces, lowercase tags, get_attribute default changed, more...)
 *
 * Examples: $array =  xml2array(file_get_contents('feed.xml'));
 *           $array =  xml2array(file_get_contents('feed.xml', true, 1, 'attribute'));
 *
 * @param string $contents The XML text
 * @param bool $namespaces true or false include namespace information in the returned array as array elements
 * @param int $get_attributes 1 or 0. If this is 1 the function will get the attributes as well as the tag values - this results in a different array structure in the return value.
 * @param string $priority Can be 'tag' or 'attribute'. This will change the way the resulting array structure. For 'tag', the tags are given more importance.
 *
 * @return array The parsed XML in an array form. Use print_r() to see the resulting array structure.
 */
function xml2array($contents, $namespaces = true, $get_attributes = 1, $priority = 'attribute')
{
    if (!$contents) {
        return [];
    }

    if (!function_exists('xml_parser_create')) {
        logger('xml2array: parser function missing');
        return [];
    }

    libxml_use_internal_errors(true);
    libxml_clear_errors();

    if ($namespaces) {
        $parser = @xml_parser_create_ns("UTF-8", ':');
    } else {
        $parser = @xml_parser_create();
    }

    if (! $parser) {
        logger('xml2array: xml_parser_create: no resource');
        return [];
    }

    xml_parser_set_option($parser, XML_OPTION_TARGET_ENCODING, "UTF-8");
    // http://minutillo.com/steve/weblog/2004/6/17/php-xml-and-character-encodings-a-tale-of-sadness-rage-and-data-loss
    xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, 0);
    xml_parser_set_option($parser, XML_OPTION_SKIP_WHITE, 1);
    @xml_parse_into_struct($parser, trim($contents), $xml_values);
    @xml_parser_free($parser);

    if (! $xml_values) {
        logger('xml2array: libxml: parse error: ' . $contents, LOGGER_DATA);
        foreach (libxml_get_errors() as $err) {
            logger('libxml: parse: ' . $err->code . " at " . $err->line . ":" . $err->column . " : " . $err->message, LOGGER_DATA);
        }
        libxml_clear_errors();

        return [];
    }

    // Initializations
    $xml_array = [];

    $current = &$xml_array; // Reference

    // Go through the tags.
    $repeated_tag_index = []; // Multiple tags with same name will be turned into an array
    foreach ($xml_values as $data) {
        unset($attributes, $value); // Remove existing values, or there will be trouble

        // This command will extract these variables into the foreach scope
        // tag(string), type(string), level(int), attributes(array).
        extract($data); // We could use the array by itself, but this cooler.

        $result = [];
        $attributes_data = [];

        if (isset($value)) {
            if ($priority == 'tag') {
                $result = $value;
            } else {
                $result['value'] = $value; // Put the value in an assoc array if we are in the 'Attribute' mode
            }
        }

        //Set the attributes too.
        if (isset($attributes) and $get_attributes) {
            foreach ($attributes as $attr => $val) {
                if ($priority == 'tag') {
                    $attributes_data[$attr] = $val;
                } else {
                    $result['@attributes'][$attr] = $val; // Set all the attributes in an array called 'attr'
                }
            }
        }

        // See tag status and do the needed.
        if ($namespaces && strpos($tag, ':')) {
            $namespc = substr($tag, 0, strrpos($tag, ':'));
            $tag = strtolower(substr($tag, strlen($namespc) + 1));
            $result['@namespace'] = $namespc;
        }
        $tag = strtolower($tag);

        if ($type == "open") {   // The starting of the tag '<tag>'
            $parent[$level - 1] = &$current;
            if (!is_array($current) or (!in_array($tag, array_keys($current)))) { // Insert New tag
                $current[$tag] = $result;
                if ($attributes_data) {
                    $current[$tag . '_attr'] = $attributes_data;
                }
                $repeated_tag_index[$tag . '_' . $level] = 1;

                $current = &$current[$tag];
            } else { // There was another element with the same tag name
                if (isset($current[$tag][0])) { // If there is a 0th element it is already an array
                    $current[$tag][$repeated_tag_index[$tag . '_' . $level]] = $result;
                    $repeated_tag_index[$tag . '_' . $level]++;
                } else { // This section will make the value an array if multiple tags with the same name appear together
                    $current[$tag] = [$current[$tag],$result]; // This will combine the existing item and the new item together to make an array
                    $repeated_tag_index[$tag . '_' . $level] = 2;

                    if (isset($current[$tag . '_attr'])) { // The attribute of the last(0th) tag must be moved as well
                        $current[$tag]['0_attr'] = $current[$tag . '_attr'];
                        unset($current[$tag . '_attr']);
                    }
                }
                $last_item_index = $repeated_tag_index[$tag . '_' . $level] - 1;
                $current = &$current[$tag][$last_item_index];
            }
        } elseif ($type == "complete") { // Tags that ends in 1 line '<tag />'
            //See if the key is already taken.
            if (!isset($current[$tag])) { //New Key
                $current[$tag] = $result;
                $repeated_tag_index[$tag . '_' . $level] = 1;
                if ($priority == 'tag' and $attributes_data) {
                    $current[$tag . '_attr'] = $attributes_data;
                }
            } else { // If taken, put all things inside a list(array)
                if (isset($current[$tag][0]) and is_array($current[$tag])) { // If it is already an array...
                    // ...push the new element into that array.
                    $current[$tag][$repeated_tag_index[$tag . '_' . $level]] = $result;

                    if ($priority == 'tag' and $get_attributes and $attributes_data) {
                        $current[$tag][$repeated_tag_index[$tag . '_' . $level] . '_attr'] = $attributes_data;
                    }
                    $repeated_tag_index[$tag . '_' . $level]++;
                } else { // If it is not an array...
                    $current[$tag] = [$current[$tag],$result]; //...Make it an array using the existing value and the new value
                    $repeated_tag_index[$tag . '_' . $level] = 1;
                    if ($priority == 'tag' and $get_attributes) {
                        if (isset($current[$tag . '_attr'])) { // The attribute of the last(0th) tag must be moved as well
                            $current[$tag]['0_attr'] = $current[$tag . '_attr'];
                            unset($current[$tag . '_attr']);
                        }

                        if ($attributes_data) {
                            $current[$tag][$repeated_tag_index[$tag . '_' . $level] . '_attr'] = $attributes_data;
                        }
                    }
                    $repeated_tag_index[$tag . '_' . $level]++; // 0 and 1 indexes are already taken
                }
            }
        } elseif ($type == 'close') { // End of tag '</tag>'
            $current = &$parent[$level - 1];
        }
    }

    return($xml_array);
}


function email_header_encode($in_str, $charset = 'UTF-8', $header = 'Subject')
{
    $out_str = $in_str;
    $need_to_convert = false;

    for ($x = 0; $x < strlen($in_str); $x++) {
        if ((ord($in_str[$x]) == 0) || ((ord($in_str[$x]) > 128))) {
            $need_to_convert = true;
            break;
        }
    }

    if (! $need_to_convert) {
        return $in_str;
    }

    if ($out_str && $charset) {
        // define start delimiter, end delimiter and spacer
        $end = "?=";
        $start = "=?" . $charset . "?B?";
        $spacer = $end . PHP_EOL . " " . $start;

        // determine length of encoded text within chunks
        // and ensure length is even
        $length = 75 - strlen($start) - strlen($end) - (strlen($header) + 2);

        /*
            [EDIT BY danbrown AT php DOT net: The following
            is a bugfix provided by (gardan AT gmx DOT de)
            on 31-MAR-2005 with the following note:
            "This means: $length should not be even,
            but divisible by 4. The reason is that in
            base64-encoding 3 8-bit-chars are represented
            by 4 6-bit-chars. These 4 chars must not be
            split between two encoded words, according
            to RFC-2047."]
        */
        $length = $length - ($length % 4);

        // encode the string and split it into chunks
        // with spacers after each chunk
        $out_str = base64_encode($out_str);
        $out_str = chunk_split($out_str, $length, $spacer);

        // remove trailing spacer and
        // add start and end delimiters
        $spacer = preg_quote($spacer, '/');
        $out_str = preg_replace("/" . $spacer . "$/", "", $out_str);
        $out_str = $start . $out_str . $end;
    }
    return $out_str;
}

/**
 * @brief
 *
 * @param string $resource
 * @param string $protocol (optional) default empty
 * @param bool $verify (optional) default true, verify HTTP signatures on Zot discovery packets.
 * @return bool|string
 */
function discover_resource(string $resource, $protocol = '', $verify = true)
{
    if (!$resource) {
        return false;
    }
    $webfinger = Webfinger::exec($resource);

    $address = EMPTY_STR;

    if ($webfinger && array_key_exists('subject', $webfinger) && str_starts_with($webfinger['subject'], 'acct:')) {
        $address = str_replace('acct:', '', $webfinger['subject']);
    }
    if ($webfinger && array_key_exists('aliases', $webfinger) && count($webfinger['aliases'])) {
        foreach ($webfinger['aliases'] as $a) {
            if (str_starts_with($a, 'acct:')) {
                $address = str_replace('acct:', '', $a);
                break;
            }
        }
    }

    $follow_url = '';

    if ($webfinger && array_key_exists('links', $webfinger) && is_array($webfinger['links'])) {

        // pull out ostatus follow links if available - these are in the actor
        // record for Nomad and Zot6, but not ActivityPub.

        $results = linksByRel($webfinger['links'], 'http://ostatus.org/schema/1.0/subscribe');
        if ($results) {
            $link = array_shift($results);
            if (array_key_exists('template', $link)) {
                $follow_url = $link['template'];
            }
        }

        $results = linksByRel($webfinger['links'], PROTOCOL_NOMAD);
        if ($results && ((! $protocol) || (strtolower($protocol) === 'nomad'))) {
            $link = array_shift($results);
            if (array_key_exists('href', $link)) {
                logger('nomad found for ' . $resource, LOGGER_DEBUG);
                $record = Zotfinger::post($link['href'], null, $verify);

                // Check the HTTP signature

                $hsig_valid = true;
                if ($verify) {
                    $hsig = $record['signature'];
                    $hsig_valid = (bool)($hsig && $hsig['signer'] === $link['href'] && $hsig['header_valid'] && $hsig['content_valid']);
                }
                if ($hsig_valid) {
                    $nomad = Libzot::import_xchan($record['data']);
                    if ($nomad['success']) {
                        return $nomad['hash'];
                    }
                }
            }
        }

        $results = linksByRel($webfinger['links'], PROTOCOL_ZOT6);
        if ($results && ((! $protocol) || (strtolower($protocol) === 'zot6'))) {
            $link = array_shift($results);
            if (array_key_exists('href', $link)) {
                logger('nomad found for ' . $resource, LOGGER_DEBUG);
                $record = Zotfinger::post($link['href'], null, $verify);

                // Check the HTTP signature

                $hsig_valid = true;
                if ($verify) {
                    $hsig = $record['signature'];
                    $hsig_valid = (bool)($hsig && $hsig['signer'] === $link['href'] && $hsig['header_valid'] && $hsig['content_valid']);
                }
                if ($hsig_valid) {
                    $zot6 = Libzot::import_xchan($record['data']);
                    if ($zot6['success']) {
                        return $zot6['hash'];
                    }
                }
            }
        }

        $results = linksByRel($webfinger['links'], 'self');
        if ($results && ((! $protocol) || (in_array(strtolower($protocol), ['activitypub', 'apnomadic'])))) {
            foreach ($results as $link) {
                if (isset($link['type']) && isset($link['href'])
                    && ($link['type'] === 'application/activity+json' || str_contains($link['type'], 'ld+json'))) {
                    $ap = ActivityPub::discover($link['href'], $webfinger, true);
                    if ($ap) {
                        // store the follow_url we found earlier
                        if ($follow_url) {
                            q("update xchan set xchan_follow = '%s' where xchan_hash = '%s'",
                                dbesc($follow_url),
                                dbesc($ap)
                            );
                        }
                        return $ap;
                    }
                }
            }
        }
    }

    if (str_starts_with($resource, 'http') && !$webfinger) {
        $record = Zotfinger::post($resource, null, $verify);

        // Check the HTTP signature

        if ($record) {
            if ($verify) {
                $hsig_valid = false;
                $hsig = $record['signature'];
                if ($hsig && $hsig['signer'] === $resource && $hsig['header_valid'] === true && $hsig['content_valid'] === true) {
                    $hsig_valid = true;
                }

                if (! $hsig_valid) {
                    logger('http signature not valid: ' . print_r($hsig, true));
                    return false;
                }
            }

            $nomad = Libzot::import_xchan($record['data']);
            if ($nomad['success']) {
                return $nomad['hash'];
            }
            return false;
        }
    }

    if (str_starts_with($resource, 'http')) {
        $ap = ActivityPub::discover($resource, $webfinger, true);
        if ($ap) {
            return $ap;
        }
    }

    logger('webfinger: ' . print_r($webfinger, true), LOGGER_DATA, LOG_INFO);

    $arr = [
            'address'   => $resource,
            'protocol'  => $protocol,
            'success'   => false,
            'xchan'     => '',
            'webfinger' => $webfinger
    ];
    /**
     * @hooks discover_channel_webfinger
     *   Called when performing a webfinger lookup.
     *   * \e string \b address - The resource
     *   * \e string \b protocol
     *   * \e array \b webfinger - The result from webfinger_rfc7033()
     *   * \e boolean \b success - The return value, default false
     */
    Hook::call('discover_channel_webfinger', $arr);
    if ($arr['success']) {
        return $arr['xchan'];
    }

    return false;
}


function linksByRel($links,$rel)
{
    $results = [];
    foreach ($links as $link) {
        if (is_array($link) && !empty($link['rel']) && $link['rel'] === $rel) {
            $results[] = $link;
        }
    }
    return $results;
}


function do_delivery($deliveries, $force = false)
{

    // $force is set if a site that wasn't responding suddenly returns to life.
    // Try and shove through everything going to that site while it's responding.

    if (! (is_array($deliveries) && count($deliveries))) {
        return;
    }

    $x = q("select count(outq_hash) as total from outq where outq_delivered = 0");
    if (intval($x[0]['total']) > intval(Config::Get('system', 'force_queue_threshold', 3000)) && (! $force)) {
        logger('immediate delivery deferred.', LOGGER_DEBUG, LOG_INFO);
        foreach ($deliveries as $d) {
            Queue::update($d, 'Delivery deferred');
        }
        return;
    }

    $interval = intval(Config::Get('system', 'delivery_interval',2));
    $deliveries_per_process = intval(Config::Get('system', 'delivery_batch_count'));

    if ($deliveries_per_process <= 0) {
        $deliveries_per_process = 1;
    }

    $deliver = [];
    foreach ($deliveries as $d) {
        if (! $d) {
            continue;
        }

        $deliver[] = $d;

        if (count($deliver) >= $deliveries_per_process) {
            Run::Summon(['Deliver', $deliver]);
            $deliver = [];
            if ($interval) {
                @time_sleep_until(microtime(true) + (float) $interval);
            }
        }
    }

    // catch any stragglers

    if ($deliver) {
        Run::Summon(['Deliver', $deliver]);
    }
}


function get_site_info()
{
    $register_policy = ['REGISTER_CLOSED', 'REGISTER_APPROVE', 'REGISTER_OPEN'];

    $r = q("select * from channel left join account on account_id = channel_account_id where ( account_roles & 4096 ) > 0 and account_default_channel = channel_id");

    if ($r) {
        $admin = [];
        foreach ($r as $rr) {
            if ($rr['channel_pageflags'] & PAGE_HUBADMIN) {
                $admin[] = ['name' => $rr['channel_name'], 'address' => Channel::get_webfinger($rr), 'channel' => z_root() . '/channel/' . $rr['channel_address']];
            }
        }
        if (! $admin) {
            foreach ($r as $rr) {
                $admin[] = ['name' => $rr['channel_name'], 'address' => Channel::get_webfinger($rr), 'channel' => z_root() . '/channel/' . $rr['channel_address']];
            }
        }
    } else {
        $admin = false;
    }

    $def_service_class = Config::Get('system', 'default_service_class');
    if ($def_service_class) {
        $service_class = Config::Get('service_class', $def_service_class);
    } else {
        $service_class = false;
    }

    $visible_plugins = Addon::list_visible();

    if (@is_dir('.git') && function_exists('shell_exec')) {
        $commit = trim(@shell_exec('git log -1 --format="%h"'));
    }
    if (! isset($commit) || strlen($commit) > 16) {
        $commit = '';
    }

    $site_info = Config::Get('system', 'info');
    $site_name = Config::Get('system', 'sitename');
    if (! Config::Get('system', 'hidden_version_siteinfo')) {
        $version = System::get_project_version();

        if (@is_dir('.git') && function_exists('shell_exec')) {
            $commit = trim(@shell_exec('git log -1 --format="%h"'));
        }

        if (! isset($commit) || strlen($commit) > 16) {
            $commit = '';
        }
    } else {
        $version = $commit = '';
    }

    $site_expire = intval(Config::Get('system', 'default_expire_days'));

    load_config('feature_lock');
    $locked_features = [];
    if (is_array(App::$config['feature_lock']) && count(App::$config['feature_lock'])) {
        foreach (App::$config['feature_lock'] as $k => $v) {
            if ($k === 'config_loaded') {
                continue;
            }
            $locked_features[$k] = intval($v);
        }
    }

    $protocols = [ 'nomad', 'zot6' ];
    if (Config::Get('system', 'activitypub', ACTIVITYPUB_ENABLED)) {
        $protocols[] = 'activitypub';
    }

    return [
        'url'                          => z_root(),
        'platform'                     => System::get_project_name(),
        'site_name'                    => (($site_name) ? $site_name : ''),
        'version'                      => $version,
        'addon_version'                => defined('ADDON_VERSION') ? ADDON_VERSION : 'unknown',
        'commit'                       => $commit,
        'protocols'                    => $protocols,
        'plugins'                      => $visible_plugins,
        'register_policy'              => $register_policy[Config::Get('system', 'register_policy')],
        'invitation_only'              => (defined('INVITE_WORKING') && intval(Config::Get('system', 'invitation_only'))),
        'language'                     => Config::Get('system', 'language'),
        'expiration'                   => $site_expire,
        'default_service_restrictions' => $service_class,
        'locked_features'              => $locked_features,
        'admin'                        => $admin,
        'dbdriver'                     => DBA::$dba->getdriver() . ' ' . ((ACTIVE_DBTYPE == DBTYPE_POSTGRES) ? 'postgres' : 'mysql'),
        'lastpoll'                     => Config::Get('system', 'lastpoll'),
        'info'                         => (($site_info) ? $site_info : '')

    ];
}


function match_access_rule($resource, $allowed, $denied, $retvalue) {
    if (is_array($allowed) && $allowed) {
        if (! (is_array($denied) && $denied)) {
            $retvalue = false;
        }
        foreach ($allowed as $entry) {
            if ($entry === '*') {
                $retvalue = true;
            }
            if ($entry && (str_contains($resource, $entry) || wildmat($entry, $resource))) {
                return true;
            }
        }
    }
    if (is_array($denied) && $denied) {
        foreach ($denied as $entry) {
            if ($entry === '*') {
                $retvalue = false;
            }
            if ($entry && (str_contains($resource, $entry) || wildmat($entry, $resource))) {
                return false;
            }
        }
    }

    return $retvalue;
}

/**
 * @brief
 *
 * @param string $url
 * @return bool
 */
function check_siteallowed($url)
{

    $retvalue = true;

    if (!(isset($url) && $url)) {
        return false;
    }

    $arr = ['url' => $url];
    /**
     * @hooks check_siteallowed
     *   Used to over-ride or bypass the site black/white block lists.
     *   * \e string \b url
     *   * \e boolean \b allowed - optional return value set in hook
     */
    Hook::call('check_siteallowed', $arr);

    if (array_key_exists('allowed', $arr)) {
        return $arr['allowed'];
    }

    // your own site is always allowed
    if (str_contains($url, z_root())) {
        return $retvalue;
    }

    $allowed = Config::Get('system', 'allowed_sites');
    $denied = Config::Get('system', 'denied_sites');
    return match_access_rule($url, $allowed, $denied, $retvalue);
}

/**
 * @brief
 *
 * @param string $url
 * @return bool
 */
function check_pubstream_siteallowed($url)
{

    $retvalue = true;

    $arr = ['url' => $url];
    /**
     * @hooks check_siteallowed
     *   Used to over-ride or bypass the site black/white block lists.
     *   * \e string \b url
     *   * \e boolean \b allowed - optional return value set in hook
     */
    Hook::call('pubstream_check_siteallowed', $arr);

    if (array_key_exists('allowed', $arr)) {
        return $arr['allowed'];
    }

    // your own site is always allowed
    if (str_contains($url, z_root())) {
        return $retvalue;
    }

    $allowed = Config::Get('system', 'pubstream_allowed_sites');
    $denied = Config::Get('system', 'pubstream_denied_sites');
    return match_access_rule($url, $allowed, $denied, $retvalue);
}

/**
 * @brief
 *
 * @param string $hash
 * @return bool
 */
function check_channelallowed($hash)
{

    $retvalue = true;

    $arr = ['hash' => $hash];
    /**
     * @hooks check_channelallowed
     *   Used to over-ride or bypass the channel allow/deny lists.
     *   * \e string \b hash
     *   * \e boolean \b allowed - optional return value set in hook
     */
    Hook::call('check_channelallowed', $arr);

    if (array_key_exists('allowed', $arr)) {
        return $arr['allowed'];
    }

    $allowed = Config::Get('system', 'allowed_channels');
    $denied = Config::Get('system', 'denied_channels');
    return match_access_rule($hash, $allowed, $denied, $retvalue);
}

/**
 * @brief
 *
 * @param string $hash
 * @return bool
 */
function check_pubstream_channelallowed($hash)
{

    $retvalue = true;

    $arr = ['hash' => $hash];
    /**
     * @hooks check_channelallowed
     *   Used to over-ride or bypass the channel black/white block lists.
     *   * \e string \b hash
     *   * \e boolean \b allowed - optional return value set in hook
     */
    Hook::call('check_pubstream_channelallowed', $arr);

    if (array_key_exists('allowed', $arr)) {
        return $arr['allowed'];
    }

    $allowed = Config::Get('system', 'pubstream_allowed_channels');
    $denied = Config::Get('system', 'pubstream_denied_channels');
    return match_access_rule($hash, $allowed, $denied, $retvalue);
}


function deliverable_singleton($channel_id, $xchan)
{

    if (array_key_exists('xchan_hash', $xchan)) {
        $xchan_hash = $xchan['xchan_hash'];
    } elseif (array_key_exists('hubloc_hash', $xchan)) {
        $xchan_hash = $xchan['hubloc_hash'];
    } else {
        return true;
    }

    $r = q(
        "select abook_instance from abook where abook_channel = %d and abook_xchan = '%s' limit 1",
        intval($channel_id),
        dbesc($xchan_hash)
    );
    if ($r) {
        if (! $r[0]['abook_instance']) {
            return true;
        }
        if (str_contains($r[0]['abook_instance'], z_root())) {
            return true;
        }
    }
    return false;
}


function get_repository_version($branch = 'release')
{
    $path = 'https://raw.codeberg.page/streams/' . REPOSITORY_ID . "/@$branch/version.php";

    $x = Url::get($path);
    if ($x['success']) {
        $y = preg_match('/define(.*?)STD_VERSION(.*?)([0-9.].*)\'/', $x['body'], $matches);
        if ($y) {
            return $matches[3];
        }
    }
    return '?.?';
}

/**
 * @brief Get translated network name.
 *
 * @param string $s Network string, see boot.php
 * @return string Translated name of the network
 */
function network_to_name($s)
{

    $nets = [
        NETWORK_FEED        => t('RSS/Atom'),
        NETWORK_ACTIVITYPUB => t('ActivityPub'),
        NETWORK_DIASPORA    => t('Diaspora'),
        NETWORK_NOMAD       => t('Nomad'),
        NETWORK_ZOT6        => t('Zot6'),
    ];

    /**
     * @hooks network_to_name
     * @deprecated
     */
    Hook::call('network_to_name', $nets);

    $search  = array_keys($nets);
    $replace = array_values($nets);

    return str_replace($search, $replace, $s);
}

/**
 * @brief Send an email message.
 *
 * @param array $params an associative array with:
 *  * \e string \b fromName        name of the sender
 *  * \e string \b fromEmail       email of the sender
 *  * \e string \b replyTo         address to direct responses
 *  * \e string \b toEmail         destination email address
 *  * \e string \b messageSubject  subject of the message
 *  * \e string \b htmlVersion     html version of the message
 *  * \e string \b textVersion     text only version of the message
 *  * \e string \b additionalMailHeader  additions to the smtp mail header
 */
function z_mail($params)
{
    if (! $params['fromEmail']) {
        $params['fromEmail'] = Config::Get('system', 'from_email');
        if (! $params['fromEmail']) {
            $params['fromEmail'] = 'Administrator' . '@' . App::get_hostname();
        }
    }
    if (! $params['fromName']) {
        $params['fromName'] = Config::Get('system', 'from_email_name');
        if (! $params['fromName']) {
            $params['fromName'] = System::get_site_name();
        }
    }
    if (! $params['replyTo']) {
        $params['replyTo'] = Config::Get('system', 'reply_address');
        if (! $params['replyTo']) {
            $params['replyTo'] = 'noreply' . '@' . App::get_hostname();
        }
    }

    $params['sent']   = false;
    $params['result'] = false;

    /**
     * @hooks email_send
     *   * \e params @see z_mail()
     */
    Hook::call('email_send', $params);

    if ($params['sent']) {
        logger('notification: z_mail (addon) returns ' . (($params['result']) ? 'success' : 'failure'), LOGGER_DEBUG);
        return $params['result'];
    }

    $mail = new PHPMailer();
    $mailer = Config::Get('phpmailer','mailer');
    if (!$mailer) {
        $mail->isSendmail();
        $s = intval(Config::Get('phpmailer','usesendmailoptions'));
        if($s) {
            $mail->UseSendmailOptions = (boolean)$s;
        }
    }
    else {
        $s = intval(Config::Get('phpmailer', 'smtpdebug'));
        if ($s) {
            // 1: debug client
            // 2: debug server (most useful setting)
            // 3: debug connection (useful for STARTTLS issues)
            // 4: debug lowlevel (very verbose)

            $mail->SMTPDebug = intval($s);
            $mail->Debugoutput = function ($str, $level) {
                logger('phpmailer: ' . $str);
            };
        }

        $mail->Hostname = App::get_hostname();

        if (Config::Get('phpmailer', 'mailer') === 'smtp') {
            $mail->IsSMTP();
            $mail->Mailer = "smtp";

            $s = Config::Get('phpmailer', 'host');
            if ($s)
                $mail->Host = $s;
            else
                $mail->Host = 'localhost';

            $s = Config::Get('phpmailer', 'port');
            if ($s)
                $mail->Port = $s;
            else
                $mail->Port = '25';

            $s = Config::Get('phpmailer', 'smtpsecure');
            if ($s)
                $mail->SMTPSecure = $s;

            $s = Config::Get('phpmailer', 'smtpauth');
            if ($s)
                $mail->SMTPAuth = (boolean)$s;

            $s = Config::Get('phpmailer', 'username');
            if ($s)
                $mail->Username = $s;

            $s = Config::Get('phpmailer', 'password');
            if ($s)
                $mail->Password = $s;


            $s = intval(Config::Get('phpmailer', 'noverify'));
            if ($s) {
                $mail->SMTPOptions = ['ssl' => [
                    'verify_peer' => false,
                    'verify_peer_name' => false,
                    'allow_self_signed' => true]
                ];
            }
        }
    }

    try {
        $mail->setFrom($params['fromEmail'], $params['fromName']);
        $mail->addReplyTo($params['replyTo']);
        $mail->addAddress($params['toEmail']);
        $mail->Subject = $params['messageSubject'];
        $mail->CharSet = 'UTF-8';

        if ($params['htmlVersion']) {
            $mail->isHTML(true);
            $mail->Body = $params['htmlVersion'];
            $mail->AltBody = $params['textVersion'];
        } else {
            $mail->isHTML(false);
            $mail->Body = $params['textVersion'];
        }

        $mail->send();

        logger('phpmailer: success');
        return true;

    } catch (Exception $e) {
        logger('phpmailer: failure: ' . $mail->ErrorInfo . '; error: ' . $e, LOGGER_DEBUG);
        return false;
    }

    /*
    $fromName = email_header_encode(html_entity_decode($params['fromName'], ENT_QUOTES, 'UTF-8'), 'UTF-8');
    $messageSubject = email_header_encode(html_entity_decode($params['messageSubject'], ENT_QUOTES, 'UTF-8'), 'UTF-8');

    $messageHeader =
        $params['additionalMailHeader'] .

        "From: $fromName <{$params['fromEmail']}>" . PHP_EOL .
        "Reply-To: $fromName <{$params['replyTo']}>" . PHP_EOL .
        "Content-Type: text/plain; charset=UTF-8";

    // send the message
    $res = mail(
        $params['toEmail'],                             // send to address
        $messageSubject,                                // subject
        $params['textVersion'],
        $messageHeader                                  // message headers
    );
    logger('notification: z_mail returns ' . (($res) ? 'success' : 'failure'), LOGGER_DEBUG);
    return $res;
    */
}


/**
 * @brief Discover the best API path available for the project servers.
 *
 * @param string $host
 * @return string
 */
function probe_api_path($host)
{

    $schemes = ['https', 'http' ];
    $paths   = ['/api/z/1.0/version', '/api/red/version' ];

    foreach ($schemes as $scheme) {
        foreach ($paths as $path) {
            $curpath = $scheme . '://' . $host . $path;
            $x = Url::get($curpath);
            if ($x['success'] && ! strpos($x['body'], 'not implemented')) {
                return str_replace('version', '', $curpath);
            }
        }
    }

    return '';
}

function service_plink($contact, $guid)
{

    $plink = '';

    $m = parse_url($contact['xchan_url']);
    if ($m) {
        $url = $m['scheme'] . '://' . $m['host'] . ((isset($m['port']) && intval($m['port'])) ? ':' . intval($m['port']) : '');
    } else {
        $url = 'https://' . substr($contact['xchan_addr'], strpos($contact['xchan_addr'], '@') + 1);
    }

    $handle = substr($contact['xchan_addr'], 0, strpos($contact['xchan_addr'], '@'));

    $plink = $url . '/channel/' . $handle . '?f=&mid=' . $guid;

    $x = [ 'xchan' => $contact, 'guid' => $guid, 'url' => $url, 'plink' => $plink ];
    /**
     * @hooks service_plink
     *   * \e array \b xchan
     *   * \e string \b guid
     *   * \e string \b url
     *   * \e string \b plink will get returned
     */
    Hook::call('service_plink', $x);

    return $x['plink'];
}


/**
 * @brief
 *
 * @param array $mimeTypes
 * @param string $acceptedTypes by default false will use $_SERVER['HTTP_ACCEPT']
 * @return array|NULL
 */
function getBestSupportedMimeType($mimeTypes = null, $acceptedTypes = false)
{
    // Values will be stored in this array
    $AcceptTypes = [];

    if ($acceptedTypes === false) {
        $acceptedTypes = ((isset($_SERVER['HTTP_ACCEPT']) && $_SERVER['HTTP_ACCEPT']) ? $_SERVER['HTTP_ACCEPT'] : EMPTY_STR);
    }

    // Accept header is case-insensitive, and whitespace isn’t important
    $accept = strtolower(str_replace(' ', '', $acceptedTypes));
    // divide it into parts in the place of a ","
    $accept = explode(',', $accept);
    foreach ($accept as $a) {
        // the default quality is 1.
        $q = 1;
        // check if there is a different quality
        if (strpos($a, ';q=')) {
            // divide "mime/type;q=X" into two parts: "mime/type" i "X"
            list($a, $q) = explode(';q=', $a);
        }
        // mime-type $a is accepted with the quality $q
        // WARNING: $q == 0 means, that mime-type isn’t supported!
        $AcceptTypes[$a] = $q;
    }
    arsort($AcceptTypes);

    // if no parameter was passed, just return parsed data
    if (!$mimeTypes) {
        return $AcceptTypes;
    }

    $filteredMimeTypes = [];
    if (! is_array($mimeTypes)) {
        $mimeTypes = [$mimeTypes];
    }
    foreach ($mimeTypes as $mime) {
        $filteredMimeTypes[] = strtolower(str_replace(' ', '', $mime));
    }
    // let’s check our supported types:
    foreach ($AcceptTypes as $mime => $q) {
        if ($q && in_array($mime, $filteredMimeTypes)) {
            return [$mime];
        }
    }

    // no mime-type found
    return null;
}


function is_https_request()
{
    $https = false;

    if (array_key_exists('HTTPS', $_SERVER) && $_SERVER['HTTPS']) {
        $https = true;
    } elseif (array_key_exists('SERVER_PORT', $_SERVER) && intval($_SERVER['SERVER_PORT']) === 443) {
        $https = true;
    } elseif (array_key_exists('HTTP_X_FORWARDED_PROTO', $_SERVER) && $_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https') {
        $https = true; // technically this is not true, but pretending it is will allow reverse proxies to work
    }

    return $https;
}

/**
 * @brief Given a URL, return everything after the host portion, but exclude any fragments.
 * example https://foobar.com/gravy?g=5&y=6
 * returns /gravy?g=5&y=6
 * example https:://foobar.com/gravy?g=5&y=6#fragment
 * also returns /gravy?g=5&y=6
 * result always returns the leading slash
 */

function get_request_string($url)
{

    $m = parse_url($url);
    if ($m) {
        return ( (isset($m['path']) ? $m['path'] : '/') . (isset($m['query']) ? '?' . $m['query'] : '') );
    }

    return '';
}