From cf0acdc1bae2514578ff4970ddce4825958b10d3 Mon Sep 17 00:00:00 2001
From: Mike Macgirvin <mike@macgirvin.com>
Date: Sun, 2 Oct 2022 00:41:06 -0700
Subject: [PATCH] experimental distance search

---
 Code/Module/Stream.php   | 40 ++++++++++++++++++++++++++++++++++++----
 include/conversation.php |  8 ++++----
 2 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/Code/Module/Stream.php b/Code/Module/Stream.php
index 0eb568f2b..94cd12a2d 100644
--- a/Code/Module/Stream.php
+++ b/Code/Module/Stream.php
@@ -86,6 +86,15 @@ class Stream extends Controller
         $distance = ((x($_REQUEST, 'distance')) ? $_REQUEST['distance'] : 0);
         $distance_from = ((x($_REQUEST,'distance_from')) ? notags(trim($_REQUEST['distance_from'])) : '');
 
+        if ($distance_from) {
+            $tmp = preg_split('/[ ,\/]/', $distance_from);
+            $distance_lat = floatval($tmp[0]);
+            $distance_lon = floatval($tmp[1]);
+            if (! ($distance_lat || $distance_lon)) {
+                $distance = 0;
+            }
+        }
+
         $c_order = get_pconfig(local_channel(), 'mod_stream', 'order', 0);
         switch ($c_order) {
             case 0:
@@ -579,18 +588,30 @@ class Stream extends Controller
             $items = fetch_post_tags($items, true);
         } elseif ($this->updating) {
             // Normal conversation view
-
             if ($order === 'post') {
                 $ordering = 'created';
             } elseif ($order === 'received') {
                 $ordering = 'changed';
+            } elseif ($distance) {
+                $ordering = 'distance asc, commented';
+                $sql_extra .= " and (lat != 0 or lon != 0) ";
             } else {
                 $ordering = 'commented';
             }
+            $base_query = ($distance)
+                ?  "SELECT item.parent AS item_id, 
+                    (6371 * acos(cos(radians(lat) )
+                    * cos( radians( $distance_lat ) )
+                    * cos( radians( $distance_lon ) - radians(lon) )
+                    + sin( radians(lat) )
+                    * sin( radians( $distance_lat ) )
+                    )) as distance from item"
+                : "SELECT item.parent AS item_id FROM item";
 
             if ($this->loading) {
                 // Fetch a page full of parent items for this page
-                $r = q("SELECT item.parent AS item_id FROM item 
+
+                $r = q("$base_query 
 					left join abook on ( item.owner_xchan = abook.abook_xchan $abook_uids )
 					$net_query
 					WHERE true $uids $item_thread_top $item_normal
@@ -599,10 +620,10 @@ class Stream extends Controller
 					$sql_extra3 $sql_extra $sql_options $sql_nets
 					$net_query2
 					ORDER BY $ordering DESC $pager_sql ");
+
             } else {
                 // this is an update
-
-                $r = q("SELECT item.parent AS item_id FROM item
+                $r = q("$base_query
 					left join abook on ( item.owner_xchan = abook.abook_xchan $abook_uids )
 					$net_query
 					WHERE true $uids $item_normal_update $simple_update
@@ -621,6 +642,17 @@ class Stream extends Controller
                     dbesc($parents_str)
                 );
 
+                if ($distance) {
+                    foreach ($r as $parent) {
+                        for($cnt = 0; $cnt < count($items); $cnt ++) {
+                            if ($parent['item_id'] === $items[$cnt]['id']) {
+                                $items[$cnt]['distance'] = $parent['distance'];
+                            }
+                        }
+                    }
+                }
+
+    
                 xchan_query($items, true);
                 $items = fetch_post_tags($items, true);
                 $items = conv_sort($items, $ordering);
diff --git a/include/conversation.php b/include/conversation.php
index a2dd3e271..f85d30a29 100644
--- a/include/conversation.php
+++ b/include/conversation.php
@@ -1604,6 +1604,8 @@ function conv_sort($arr, $order)
 
     if (stristr($order, 'created')) {
         usort($parents, 'sort_thr_created');
+    } elseif (stristr($order, 'distance')) {
+        usort($parents, 'sort_thr_distance');
     } elseif (stristr($order, 'commented')) {
         usort($parents, 'sort_thr_commented');
     } elseif (stristr($order, 'updated')) {
@@ -1612,8 +1614,6 @@ function conv_sort($arr, $order)
         usort($parents, 'sort_thr_received');
     } elseif (stristr($order, 'ascending')) {
         usort($parents, 'sort_thr_created_rev');
-    } elseif (stristr($order, 'distance')) {
-        usort($parents, 'sort_thr_distance');
     }
     if ($parents) {
         foreach ($parents as $i => $_x) {
@@ -1714,7 +1714,7 @@ function sort_thr_distance($a, $b)
     if (!isset($b['distance'])) {
         $b['distance'] = 999999999;
     }
-    return strcmp($b['distance'], $a['distance']);
+    return floatval($a['distance']) <=> floatval($b['distance']);
 }
 
 function sort_thr_updated($a, $b)
@@ -1746,7 +1746,7 @@ function format_location($item)
         Hook::call('render_location', $locate);
         $location = ((strlen($locate['html'])) ? $locate['html'] : render_location_default($locate));
     }
-    return $location;
+    return $location . (!empty($item['distance']) ? t(' distance: ') . sprintf("%05.03f km",$item['distance']) : '');
 }
 
 function render_location_default($item)