From d404f15312320dbe1f516db7bb91944182ad5d26 Mon Sep 17 00:00:00 2001
From: Michael <heluecht@pirati.ca>
Date: Mon, 14 Feb 2022 22:04:33 +0000
Subject: [PATCH] Improve local forum distribution

---
 src/Model/Item.php                       | 52 ++++++++++++++++++++++--
 src/Protocol/ActivityPub/Transmitter.php | 31 +++++++++-----
 2 files changed, 69 insertions(+), 14 deletions(-)

diff --git a/src/Model/Item.php b/src/Model/Item.php
index 6749dc238..fd0dbde2b 100644
--- a/src/Model/Item.php
+++ b/src/Model/Item.php
@@ -1402,9 +1402,15 @@ class Item
 		}
 
 		if ((($item['gravity'] == GRAVITY_COMMENT) || $is_reshare) && !Post::exists(['uri-id' => $item['thr-parent-id'], 'uid' => $uid])) {
-			// Only do an auto complete with the source uid "0" to prevent privavy problems
+			// Fetch the origin user for the post
+			$origin_uid = self::GetOriginUidForUriId($item['thr-parent-id'], $uid);
+			if (is_null($origin_uid)) {
+				Logger::info('Origin item was not found', ['uid' => $uid, 'uri-id' => $item['thr-parent-id']]);
+				return 0;
+			}
+
 			$causer = $item['causer-id'] ?: $item['author-id'];
-			$result = self::storeForUserByUriId($item['thr-parent-id'], $uid, ['causer-id' => $causer, 'post-reason' => self::PR_FETCHED]);
+			$result = self::storeForUserByUriId($item['thr-parent-id'], $uid, ['causer-id' => $causer, 'post-reason' => self::PR_FETCHED], $origin_uid);
 			Logger::info('Fetched thread parent', ['uri-id' => $item['thr-parent-id'], 'uid' => $uid, 'causer' => $causer, 'result' => $result]);
 		}
 
@@ -1413,6 +1419,46 @@ class Item
 		return $stored;
 	}
 
+	/**
+	 * Returns the origin uid of a post if the given user is allowed to see it.
+	 *
+	 * @param int $uriid
+	 * @param int $uid
+	 * @return int
+	 */
+	private static function GetOriginUidForUriId(int $uriid, int $uid)
+	{
+		if (Post::exists(['uri-id' => $uriid, 'uid' => $uid])) {
+			return $uid;
+		}
+
+		$post = Post::selectFirst(['uid', 'allow_cid', 'allow_gid', 'deny_cid', 'deny_gid', 'private'], ['uri-id' => $uriid, 'origin' => true]);
+		if (empty($post)) {
+			if (Post::exists(['uri-id' => $uriid, 'uid' => 0])) {
+				return 0;
+			} else {
+				return null;
+			}
+		}
+
+		if (in_array($post['private'], [Item::PUBLIC, Item::UNLISTED])) {
+			return $post['uid'];
+		}
+
+		$pcid = Contact::getPublicIdByUserId($uid);
+		if (empty($pcid)) {
+			return null;
+		}
+
+		foreach (Item::enumeratePermissions($post, true) as $receiver) {
+			if ($receiver == $pcid) {
+				return $post['uid'];
+			}
+		}
+
+		return null;
+	}
+
 	/**
 	 * Store a public item array for the given users
 	 *
@@ -1928,7 +1974,7 @@ class Item
 
 			$allow_cid = '<' . $owner['id'] . '>';
 			$allow_gid = '<' . Group::getIdForForum($owner['id']) . '>';
-			$deny_cid  = ''; 
+			$deny_cid  = '';
 			$deny_gid  = '';
 			self::performActivity($item['id'], 'announce', $uid, $allow_cid, $allow_gid, $deny_cid, $deny_gid);
 		} else {
diff --git a/src/Protocol/ActivityPub/Transmitter.php b/src/Protocol/ActivityPub/Transmitter.php
index 663862f79..7be55898c 100644
--- a/src/Protocol/ActivityPub/Transmitter.php
+++ b/src/Protocol/ActivityPub/Transmitter.php
@@ -600,23 +600,32 @@ class Transmitter
 						continue;
 					}
 
-					if (!empty($profile = APContact::getByURL($contact['url'], false))) {
+					$profile = APContact::getByURL($term['url'], false);
+					if (!empty($profile)) {
+						if ($term['type'] == Tag::EXCLUSIVE_MENTION) {
+							$exclusive = true;
+							if (!empty($profile['followers']) && ($profile['type'] == 'Group')) {
+								$data['cc'][] = $profile['followers'];
+							}
+						}
 						$data['to'][] = $profile['url'];
 					}
 				}
 			}
 
-			foreach ($receiver_list as $receiver) {
-				$contact = DBA::selectFirst('contact', ['url', 'hidden', 'network', 'protocol', 'gsid'], ['id' => $receiver, 'network' => Protocol::FEDERATED]);
-				if (!DBA::isResult($contact) || !self::isAPContact($contact, $networks)) {
-					continue;
-				}
+			if (!$exclusive) {
+				foreach ($receiver_list as $receiver) {
+					$contact = DBA::selectFirst('contact', ['url', 'hidden', 'network', 'protocol', 'gsid'], ['id' => $receiver, 'network' => Protocol::FEDERATED]);
+					if (!DBA::isResult($contact) || !self::isAPContact($contact, $networks)) {
+						continue;
+					}
 
-				if (!empty($profile = APContact::getByURL($contact['url'], false))) {
-					if ($contact['hidden'] || $always_bcc) {
-						$data['bcc'][] = $profile['url'];
-					} else {
-						$data['cc'][] = $profile['url'];
+					if (!empty($profile = APContact::getByURL($contact['url'], false))) {
+						if ($contact['hidden'] || $always_bcc) {
+							$data['bcc'][] = $profile['url'];
+						} else {
+							$data['cc'][] = $profile['url'];
+						}
 					}
 				}
 			}