feat: show reactions in summaries (#5387)

shows the last reaction in chatlist's summaries if there is no
newer message.

the reason to show reactions in the summary, is to make them a _little_
more visible when one is not in the chat. esp. in not-so-chatty or in
one-to-ones chats this becomes handy: imaging a question and someone
"answers" with "thumbs up" ... 

otoh, reactions are still tuned down on purpose: no notifications, chats
are opend as usual, the chatlist is not sorted by reactions and also the
date in the summary refer to the last message - i thought quite a bit
about that, this seems to be good compromise and will raise the fewest
questions. it is somehow clear to the users that reactions are not the
same as a real message. also, it is comparable easy to implement - no
UI changes required :)

all that is very close to what whatsapp is doing (figured that out by
quite some testing ... to cite @adbenitez: if in doubt, we can blame
whatsapp :)

technically, i first wanted to go for the "big solution" and add two
more columns, chat_id and timestamp, however, it seemed a bit bloated if
we really only need the last one. therefore, i just added the last
reaction information to the chat's param, which seems more performant
but also easier to code :)

src/summary.rs

@@ -10,7 +10,9 @@ use crate::context::Context;
 use crate::message::{Message, MessageState, Viewtype};
 use crate::mimeparser::SystemMessage;
 use crate::stock_str;
+use crate::stock_str::msg_reacted;
 use crate::tools::truncate;
+use anyhow::Result;
 
 /// Prefix displayed before message and separated by ":" in the chatlist.
 #[derive(Debug)]
@@ -62,7 +64,24 @@ impl Summary {
         msg: &Message,
         chat: &Chat,
         contact: Option<&Contact>,
-    ) -> Self {
+    ) -> Result<Summary> {
+        if let Some((reaction_msg, reaction_contact_id, reaction)) = chat
+            .get_last_reaction_if_newer_than(context, msg.timestamp_sort)
+            .await?
+        {
+            // there is a reaction newer than the latest message, show that.
+            // sorting and therefore date is still the one of the last message,
+            // the reaction is is more sth. that overlays temporarily.
+            let summary = reaction_msg.get_summary_text(context).await;
+            return Ok(Summary {
+                prefix: None,
+                text: msg_reacted(context, reaction_contact_id, &reaction, &summary).await,
+                timestamp: msg.get_timestamp(), // message timestamp (not reaction) to make timestamps more consistent with chats ordering
+                state: msg.state, // message state (not reaction) - indicating if it was me sending the last message
+                thumbnail_path: None,
+            });
+        }
+
         let prefix = if msg.state == MessageState::OutDraft {
             Some(SummaryPrefix::Draft(stock_str::draft(context).await))
         } else if msg.from_id == ContactId::SELF {
@@ -102,13 +121,13 @@ impl Summary {
             None
         };
 
-        Self {
+        Ok(Summary {
             prefix,
             text,
             timestamp: msg.get_timestamp(),
             state: msg.state,
             thumbnail_path,
-        }
+        })
     }
 
     /// Returns the [`Summary::text`] attribute truncated to an approximate length.