New algorithm for reply_to saving

I changed the reply-to algorithm so that we only say a notice is in
reply to another notice if a) we receive that information from the Web
or API or b) it's in a "low bandwidth" (XMPP, SMS) channel, and begins
with "@nickname" or "T NICKNAME".

The goal is to avoid false-positives and make conversation trees more
accurate and useful.

1 files changed, 116 insertions, 42 deletions

diff --git a/classes/Notice.php b/classes/Notice.php
index c2770edbe..ebd5e1efd 100644
--- a/classes/Notice.php
+++ b/classes/Notice.php
@@ -102,15 +102,14 @@ class Notice extends Memcached_DataObject
         if (!$count) {
             return true;
         }
-        
+
         //turn each into their canonical tag
         //this is needed to remove dupes before saving e.g. #hash.tag = #hashtag
         $hashtags = array();
         for($i=0; $i<count($match[1]); $i++) {
-             $hashtags[] = common_canonical_tag($match[1][$i]);
+            $hashtags[] = common_canonical_tag($match[1][$i]);
         }
 
- 
         /* Add them to the database */
         foreach(array_unique($hashtags) as $hashtag) {
             /* elide characters we don't want in the tag */
@@ -183,29 +182,30 @@ class Notice extends Memcached_DataObject
             $notice->is_local = $is_local;
         }
 
-		$notice->query('BEGIN');
-
-		$notice->reply_to = $reply_to;
         if (!empty($created)) {
             $notice->created = $created;
         } else {
             $notice->created = common_sql_now();
         }
+
 		$notice->content = $final;
 		$notice->rendered = common_render_content($final, $notice);
 		$notice->source = $source;
 		$notice->uri = $uri;
 
-        if (!empty($reply_to)) {
-            $reply_notice = Notice::staticGet('id', $reply_to);
-            if (!empty($reply_notice)) {
-                $notice->reply_to = $reply_to;
-                $notice->conversation = $reply_notice->conversation;
-            }
+		$notice->reply_to = self::getReplyTo($reply_to, $profile_id, $source, $final);
+
+        if (!empty($notice->reply_to)) {
+            $reply = Notice::staticGet('id', $notice->reply_to);
+            $notice->conversation = $reply->conversation;
         }
 
         if (Event::handle('StartNoticeSave', array(&$notice))) {
 
+            // XXX: some of these functions write to the DB
+
+            $notice->query('BEGIN');
+
             $id = $notice->insert();
 
             if (!$id) {
@@ -213,18 +213,33 @@ class Notice extends Memcached_DataObject
                 return _('Problem saving notice.');
             }
 
-            # Update the URI after the notice is in the database
-            if (!$uri) {
-                $orig = clone($notice);
+            // Update ID-dependent columns: URI, conversation
+
+            $orig = clone($notice);
+
+            $changed = false;
+
+            if (empty($uri)) {
                 $notice->uri = common_notice_uri($notice);
+                $changed = true;
+            }
+
+            // If it's not part of a conversation, it's
+            // the beginning of a new conversation.
 
+            if (empty($notice->conversation)) {
+                $notice->conversation = $notice->id;
+                $changed = true;
+            }
+
+            if ($changed) {
                 if (!$notice->update($orig)) {
                     common_log_db_error($notice, 'UPDATE', __FILE__);
                     return _('Problem saving notice.');
                 }
             }
 
-            # XXX: do we need to change this for remote users?
+            // XXX: do we need to change this for remote users?
 
             $notice->saveReplies();
             $notice->saveTags();
@@ -232,8 +247,13 @@ class Notice extends Memcached_DataObject
             $notice->addToInboxes();
 
             $notice->saveUrls();
+
+            // FIXME: why do we have to re-render the content?
+            // Remove this if it's not necessary.
+
             $orig2 = clone($notice);
-    		$notice->rendered = common_render_content($final, $notice);
+
+            $notice->rendered = common_render_content($final, $notice);
             if (!$notice->update($orig2)) {
                 common_log_db_error($notice, 'UPDATE', __FILE__);
                 return _('Problem saving notice.');
@@ -290,9 +310,9 @@ class Notice extends Memcached_DataObject
         $notice->profile_id = $profile_id;
         $notice->content = $content;
         if (common_config('db','type') == 'pgsql')
-            $notice->whereAdd('extract(epoch from now() - created) < ' . common_config('site', 'dupelimit'));
+          $notice->whereAdd('extract(epoch from now() - created) < ' . common_config('site', 'dupelimit'));
         else
-            $notice->whereAdd('now() - created < ' . common_config('site', 'dupelimit'));
+          $notice->whereAdd('now() - created < ' . common_config('site', 'dupelimit'));
 
         $cnt = $notice->count();
         return ($cnt == 0);
@@ -906,14 +926,14 @@ class Notice extends Memcached_DataObject
     {
         $user = new User();
 
-	if(common_config('db','quote_identifiers'))
-	    $user_table = '"user"';
-	else $user_table = 'user';
+        if(common_config('db','quote_identifiers'))
+          $user_table = '"user"';
+        else $user_table = 'user';
 
         $qry =
           'SELECT id ' .
-	  'FROM '. $user_table .' JOIN subscription '.
-	  'ON '. $user_table .'.id = subscription.subscriber ' .
+          'FROM '. $user_table .' JOIN subscription '.
+          'ON '. $user_table .'.id = subscription.subscriber ' .
           'WHERE subscription.subscribed = %d ';
 
         $user->query(sprintf($qry, $this->profile_id));
@@ -1031,16 +1051,6 @@ class Notice extends Memcached_DataObject
             if (!$recipient) {
                 continue;
             }
-            if ($i == 0 && ($recipient->id != $sender->id) && !$this->reply_to) { // Don't save reply to self
-                $reply_for = $recipient;
-                $recipient_notice = $reply_for->getCurrentNotice();
-                if ($recipient_notice) {
-                    $orig = clone($this);
-                    $this->reply_to = $recipient_notice->id;
-                    $this->conversation = $recipient_notice->conversation;
-                    $this->update($orig);
-                }
-            }
             // Don't save replies from blocked profile to local user
             $recipient_user = User::staticGet('id', $recipient->id);
             if ($recipient_user && $recipient_user->hasBlocked($sender)) {
@@ -1087,14 +1097,6 @@ class Notice extends Memcached_DataObject
             }
         }
 
-        // If it's not a reply, make it the root of a new conversation
-
-        if (empty($this->conversation)) {
-            $orig = clone($this);
-            $this->conversation = $this->id;
-            $this->update($orig);
-        }
-
         foreach (array_keys($replied) as $recipient) {
             $user = User::staticGet('id', $recipient);
             if ($user) {
@@ -1266,4 +1268,76 @@ class Notice extends Memcached_DataObject
 
         return $ids;
     }
+
+    /**
+     * Determine which notice, if any, a new notice is in reply to.
+     *
+     * For conversation tracking, we try to see where this notice fits
+     * in the tree. Rough algorithm is:
+     *
+     * if (reply_to is set and valid) {
+     *     return reply_to;
+     * } else if ((source not API or Web) and (content starts with "T NAME" or "@name ")) {
+     *     return ID of last notice by initial @name in content;
+     * }
+     *
+     * Note that all @nickname instances will still be used to save "reply" records,
+     * so the notice shows up in the mentioned users' "replies" tab.
+     *
+     * @param integer $reply_to   ID passed in by Web or API
+     * @param integer $profile_id ID of author
+     * @param string  $source     Source tag, like 'web' or 'gwibber'
+     * @param string  $content    Final notice content
+     *
+     * @return integer ID of replied-to notice, or null for not a reply.
+     */
+
+    static function getReplyTo($reply_to, $profile_id, $source, $content)
+    {
+        static $lb = array('xmpp', 'mail', 'sms', 'omb');
+
+        // If $reply_to is specified, we check that it exists, and then
+        // return it if it does
+
+        if (!empty($reply_to)) {
+            $reply_notice = Notice::staticGet('id', $reply_to);
+            if (!empty($reply_notice)) {
+                return $reply_to;
+            }
+        }
+
+        // If it's not a "low bandwidth" source (one where you can't set
+        // a reply_to argument), we return. This is mostly web and API
+        // clients.
+
+        if (!in_array($source, $lb)) {
+            return null;
+        }
+
+        // Is there an initial @ or T?
+
+        if (preg_match('/^T ([A-Z0-9]{1,64}) /', $content, $match) ||
+            preg_match('/^@([a-z0-9]{1,64})\s+/', $content, $match)) {
+            $nickname = common_canonical_nickname($match[1]);
+        } else {
+            return null;
+        }
+
+        // Figure out who that is.
+
+        $sender = Profile::staticGet('id', $profile_id);
+        $recipient = common_relative_profile($sender, $nickname, common_sql_now());
+
+        if (empty($recipient)) {
+            return null;
+        }
+
+        // Get their last notice
+
+        $last = $recipient->getCurrentNotice();
+
+        if (!empty($last)) {
+            return $last->id;
+        }
+    }
 }