From 9ed1ee90f84e11c891a9d287a7b6ec480c1200b7 Mon Sep 17 00:00:00 2001
From: Scott Nonnenberg <scott@signal.org>
Date: Mon, 6 Aug 2018 11:31:41 -0700
Subject: [PATCH] Move expiring message time earlier if read sync has earlier
 time

---
 js/models/conversations.js |  1 +
 js/models/messages.js      |  4 +--
 js/read_syncs.js           | 53 +++++++++++++++++++++++++-------------
 3 files changed, 38 insertions(+), 20 deletions(-)

diff --git a/js/models/conversations.js b/js/models/conversations.js
index aa8b9c3421ac..cba3f5e296f4 100644
--- a/js/models/conversations.js
+++ b/js/models/conversations.js
@@ -139,6 +139,7 @@
       // Listening for out-of-band data updates
       this.on('delivered', this.updateAndMerge);
       this.on('read', this.updateAndMerge);
+      this.on('expiration-change', this.updateAndMerge);
       this.on('expired', this.onExpired);
     },
 
diff --git a/js/models/messages.js b/js/models/messages.js
index 0c553b47250c..b8e485508990 100644
--- a/js/models/messages.js
+++ b/js/models/messages.js
@@ -1289,8 +1289,8 @@
       }
       return msFromNow;
     },
-    async setToExpire() {
-      if (this.isExpiring() && !this.get('expires_at')) {
+    async setToExpire(force = false) {
+      if (this.isExpiring() && (force || !this.get('expires_at'))) {
         const start = this.get('expirationStartTimestamp');
         const delta = this.get('expireTimer') * 1000;
         const expiresAt = start + delta;
diff --git a/js/read_syncs.js b/js/read_syncs.js
index 81a0c0705b51..4732445c3509 100644
--- a/js/read_syncs.js
+++ b/js/read_syncs.js
@@ -1,4 +1,4 @@
-/* global Backbone, Whisper, ConversationController */
+/* global Backbone, Whisper */
 
 /* eslint-disable more/no-then */
 
@@ -32,9 +32,7 @@
 
         const message = messages.find(
           item =>
-            item.isIncoming() &&
-            item.isUnread() &&
-            item.get('source') === receipt.get('sender')
+            item.isIncoming() && item.get('source') === receipt.get('sender')
         );
         const notificationForMessage = message
           ? Whisper.Notifications.findWhere({ messageId: message.id })
@@ -59,11 +57,39 @@
           return;
         }
 
-        await message.markRead(receipt.get('read_at'));
-        // This notification may result in messages older than this one being
-        //   marked read. We want those messages to have the same expire timer
-        //   start time as this one, so we pass the read_at value through.
-        this.notifyConversation(message, receipt.get('read_at'));
+        const readAt = receipt.get('read_at');
+
+        // If message is unread, we mark it read. Otherwise, we update the expiration
+        //   timer to the time specified by the read sync if it's earlier than
+        //   the previous read time.
+        if (message.isUnread()) {
+          await message.markRead(readAt);
+
+          // onReadMessage may result in messages older than this one being
+          //   marked read. We want those messages to have the same expire timer
+          //   start time as this one, so we pass the readAt value through.
+          const conversation = message.getConversation();
+          if (conversation) {
+            conversation.onReadMessage(message, readAt);
+          }
+        } else {
+          const now = Date.now();
+          const existingTimestamp = message.get('expirationStartTimestamp');
+          const expirationStartTimestamp = Math.min(
+            now,
+            Math.min(existingTimestamp || now, readAt || now)
+          );
+          message.set({ expirationStartTimestamp });
+
+          const force = true;
+          await message.setToExpire(force);
+
+          const conversation = message.getConversation();
+          if (conversation) {
+            conversation.trigger('expiration-change', message);
+          }
+        }
+
         this.remove(receipt);
       } catch (error) {
         window.log.error(
@@ -72,14 +98,5 @@
         );
       }
     },
-    notifyConversation(message, readAt) {
-      const conversation = ConversationController.get({
-        id: message.get('conversationId'),
-      });
-
-      if (conversation) {
-        conversation.onReadMessage(message, readAt);
-      }
-    },
   }))();
 })();