fix: markseen_msgs: Limit not yet downloaded messages state to InNoticed (#2970)

This fixes sending MDNs for big messages when they are downloaded and really seen. Otherwise MDNs
are not sent for big encrypted messages because they "don't want MDN" until downloaded.

Author: iequidoo

src/message.rs

@@ -1693,6 +1693,7 @@ pub async fn markseen_msgs(context: &Context, msg_ids: Vec<MsgId>) -> Result<()>
                     m.id AS id,
                     m.chat_id AS chat_id,
                     m.state AS state,
+                    m.download_state as download_state,
                     m.ephemeral_timer AS ephemeral_timer,
                     m.param AS param,
                     m.from_id AS from_id,
@@ -1708,6 +1709,7 @@ pub async fn markseen_msgs(context: &Context, msg_ids: Vec<MsgId>) -> Result<()>
                 let id: MsgId = row.get("id")?;
                 let chat_id: ChatId = row.get("chat_id")?;
                 let state: MessageState = row.get("state")?;
+                let download_state: DownloadState = row.get("download_state")?;
                 let param: Params = row.get::<_, String>("param")?.parse().unwrap_or_default();
                 let from_id: ContactId = row.get("from_id")?;
                 let rfc724_mid: String = row.get("rfc724_mid")?;
@@ -1719,6 +1721,7 @@ pub async fn markseen_msgs(context: &Context, msg_ids: Vec<MsgId>) -> Result<()>
                         id,
                         chat_id,
                         state,
+                        download_state,
                         param,
                         from_id,
                         rfc724_mid,
@@ -1748,6 +1751,7 @@ pub async fn markseen_msgs(context: &Context, msg_ids: Vec<MsgId>) -> Result<()>
             id,
             curr_chat_id,
             curr_state,
+            curr_download_state,
             curr_param,
             curr_from_id,
             curr_rfc724_mid,
@@ -1757,7 +1761,14 @@ pub async fn markseen_msgs(context: &Context, msg_ids: Vec<MsgId>) -> Result<()>
         _curr_ephemeral_timer,
     ) in msgs
     {
-        if curr_state == MessageState::InFresh || curr_state == MessageState::InNoticed {
+        if curr_download_state != DownloadState::Done {
+            if curr_state == MessageState::InFresh {
+                // Don't mark partially downloaded messages as seen or send a read receipt since
+                // they are not really seen by the user.
+                update_msg_state(context, id, MessageState::InNoticed).await?;
+                updated_chat_ids.insert(curr_chat_id);
+            }
+        } else if curr_state == MessageState::InFresh || curr_state == MessageState::InNoticed {
             update_msg_state(context, id, MessageState::InSeen).await?;
             info!(context, "Seen message {}.", id);
 
@@ -2601,8 +2612,28 @@ mod tests {
         assert!(!msg.param.get_bool(Param::WantsMdn).unwrap_or_default());
         assert_eq!(msg.state, MessageState::InFresh);
         markseen_msgs(alice, vec![msg.id]).await?;
-        let msg = Message::load_from_db(alice, msg.id).await?;
-        assert_eq!(msg.state, MessageState::InSeen);
+        // A not downloaded message can be seen only if it's seen on another device.
+        assert_eq!(msg.id.get_state(alice).await?, MessageState::InNoticed);
+        // Marking the message as seen again is a no op.
+        markseen_msgs(alice, vec![msg.id]).await?;
+        assert_eq!(msg.id.get_state(alice).await?, MessageState::InNoticed);
+
+        msg.id
+            .update_download_state(alice, DownloadState::InProgress)
+            .await?;
+        markseen_msgs(alice, vec![msg.id]).await?;
+        assert_eq!(msg.id.get_state(alice).await?, MessageState::InNoticed);
+        msg.id
+            .update_download_state(alice, DownloadState::Failure)
+            .await?;
+        markseen_msgs(alice, vec![msg.id]).await?;
+        assert_eq!(msg.id.get_state(alice).await?, MessageState::InNoticed);
+        msg.id
+            .update_download_state(alice, DownloadState::Undecipherable)
+            .await?;
+        markseen_msgs(alice, vec![msg.id]).await?;
+        assert_eq!(msg.id.get_state(alice).await?, MessageState::InNoticed);
+
         assert!(
             !alice
                 .sql
@@ -2611,12 +2642,25 @@ mod tests {
         );
 
         alice.set_config(Config::DownloadLimit, None).await?;
+        // Let's assume that Alice and Bob resolved the problem with encryption.
+        let old_msg = msg;
         let msg = alice.recv_msg(&sent_msg).await;
+        assert_eq!(msg.chat_id, old_msg.chat_id);
         assert_eq!(msg.download_state, DownloadState::Done);
         assert!(msg.param.get_bool(Param::WantsMdn).unwrap_or_default());
         assert!(msg.get_showpadlock());
+        // The message state mustn't be downgraded to `InFresh`.
+        assert_eq!(msg.state, MessageState::InNoticed);
+        markseen_msgs(alice, vec![msg.id]).await?;
+        let msg = Message::load_from_db(alice, msg.id).await?;
         assert_eq!(msg.state, MessageState::InSeen);
-
+        assert_eq!(
+            alice
+                .sql
+                .count("SELECT COUNT(*) FROM smtp_mdns", ())
+                .await?,
+            1
+        );
         Ok(())
     }