wip smart split to fit instance character limit

src/group_handler/handle_mention.rs

@@ -262,8 +262,30 @@ impl<'a> ProcessMention<'a> {
                 apply_trailing_hashtag_pleroma_bug_workaround(&mut msg);
             }
 
+            let mention = format!("@{user}", user = self.status_acct);
+            self.send_reply_multipart(mention, msg).await?;
+        }
+
+        if !self.announcements.is_empty() {
+            let mut msg = self.announcements.join("\n");
+            debug!("a={}", msg);
+
+            if self.want_markdown {
+                apply_trailing_hashtag_pleroma_bug_workaround(&mut msg);
+            }
+
+            let msg = format!("**📢 Group announcement**\n{msg}", msg = msg);
+            self.send_announcement_multipart(&msg).await?;
+        }
+
+        Ok(())
+    }
+
+    async fn send_reply_multipart(&self, mention : String, msg : String) -> Result<(), GroupError> {
+        let parts = smart_split(&msg, Some(mention), self.config.get_character_limit());
+        for p in parts {
             if let Ok(post) = StatusBuilder::new()
-                .status(format!("@{user} {msg}", user = self.status_acct, msg = msg))
+                .status(p)
                 .content_type(if self.want_markdown {
                     "text/markdown"
                 } else {
@@ -272,30 +294,31 @@ impl<'a> ProcessMention<'a> {
                 .visibility(Visibility::Direct)
                 .build()
             {
-                let _ = self.client.new_status(post)
-                    .await.log_error("Failed to post");
-                // Sleep a bit to avoid throttling
-                tokio::time::sleep(Duration::from_secs(1)).await;
+                self.client.new_status(post).await?;
             }
+
+            // Sleep a bit to avoid throttling
+            tokio::time::sleep(Duration::from_secs(1)).await;
         }
 
-        if !self.announcements.is_empty() {
-            let mut msg = self.announcements.join("\n");
-            debug!("a={}", msg);
+        Ok(())
+    }
 
-            if self.want_markdown {
-                apply_trailing_hashtag_pleroma_bug_workaround(&mut msg);
-            }
+    async fn send_announcement_multipart(&self, msg : &str) -> Result<(), GroupError> {
+        let parts = smart_split(msg, None, self.config.get_character_limit());
 
+        for p in parts {
             let post = StatusBuilder::new()
-                .status(format!("**📢 Group announcement**\n{msg}", msg = msg))
+                .status(p)
                 .content_type("text/markdown")
                 .visibility(Visibility::Public)
                 .build()
                 .expect("error build status");
 
-            let _ = self.client.new_status(post)
-                .await.log_error("Failed to post");
+            self.client.new_status(post).await?;
+
+            // Sleep a bit to avoid throttling
+            tokio::time::sleep(Duration::from_secs(1)).await;
         }
 
         Ok(())
@@ -772,3 +795,95 @@ fn apply_trailing_hashtag_pleroma_bug_workaround(msg: &mut String) {
         msg.push_str(" .");
     }
 }
+
+fn smart_split(msg : &str, prefix: Option<String>, limit: usize) -> Vec<String> {
+    let prefix = prefix.unwrap_or_default();
+
+    if msg.len() + prefix.len() < limit {
+        return vec![format!("{}{}", prefix, msg)];
+    }
+
+    let mut parts_to_send = vec![];
+    let mut this_piece = prefix.clone();
+    for l in msg.split("\n") {
+        if this_piece.len() + l.len() == limit {
+            this_piece.push_str(l);
+            parts_to_send.push(std::mem::take(&mut this_piece).trim().to_owned());
+            this_piece.push_str(&prefix);
+        } else if this_piece.len() + l.len() > limit {
+            let trimmed = this_piece.trim();
+            if !trimmed.is_empty() {
+                parts_to_send.push(trimmed.to_owned());
+            }
+
+            // start new piece
+            this_piece = format!("{}{}", prefix, l);
+
+            while this_piece.len() > limit {
+                let to_send = if let Some(last_space) = (&this_piece[..limit]).rfind(' ') {
+                    let mut p = this_piece.split_off(last_space);
+                    std::mem::swap(&mut p, &mut this_piece);
+                    p
+                } else {
+                    let mut p = this_piece.split_off(limit);
+                    std::mem::swap(&mut p, &mut this_piece);
+                    p
+                };
+                parts_to_send.push(to_send);
+                this_piece = format!("{}{}", prefix, this_piece);
+            }
+            this_piece.push('\n');
+        } else {
+            this_piece.push_str(l);
+            this_piece.push('\n');
+        }
+    }
+
+    parts_to_send
+}
+
+#[cfg(test)]
+mod test {
+    #[test]
+    fn test_smart_split1() {
+        let to_split = "a234567890\nb234567890\nc234567890\nd234\n67890\ne234567890\n";
+
+        let parts = super::smart_split(to_split, None, 10);
+        assert_eq!(vec![
+            "a234567890".to_string(),
+            "b234567890".to_string(),
+            "c234567890".to_string(),
+            "d234\n67890".to_string(),
+            "e234567890".to_string(),
+        ], parts);
+    }
+
+    #[test]
+    fn test_smart_split2() {
+        let to_split = "foo\nbar\nbaz";
+
+        let parts = super::smart_split(to_split, None, 1000);
+        assert_eq!(vec![
+            "foo\nbar\nbaz".to_string(),
+        ], parts);
+    }
+
+    #[test]
+    fn test_smart_split3() {
+        let to_split = "foo\nbar\nbaz";
+        let parts = super::smart_split(to_split, Some("PREFIX".to_string()), 1000);
+        assert_eq!(vec![
+            "PREFIXfoo\nbar\nbaz".to_string(),
+        ], parts);
+    }
+
+    #[test]
+    fn test_smart_split4() {
+        let to_split = "1234\n56\n7";
+        let parts = super::smart_split(to_split, Some("PREFIX".to_string()), 10);
+        assert_eq!(vec![
+            "PREFIX1234".to_string(),
+            "PREFIX56\n7".to_string(),
+        ], parts);
+    }
+}

src/store/data.rs

@@ -33,6 +33,8 @@ pub(crate) struct GroupConfig {
     acct: String,
     /// elefren data
     appdata: AppData,
+    /// Server's character limit
+    character_limit: usize,
     /// Hashtags the group will auto-boost from it's members
     group_tags: HashSet<String>,
     /// List of admin account "acct" names, e.g. piggo@piggo.space
@@ -67,6 +69,7 @@ impl Default for GroupConfig {
                 redirect: Default::default(),
                 token: Default::default(),
             },
+            character_limit: 5000,
             group_tags: Default::default(),
             admin_users: Default::default(),
             member_users: Default::default(),
@@ -90,6 +93,10 @@ impl GroupConfig {
         }
     }
 
+    pub(crate) fn get_character_limit(&self) -> usize {
+        self.character_limit
+    }
+
     pub(crate) fn is_enabled(&self) -> bool {
         self.enabled
     }

src/store/mod.rs

@@ -232,19 +232,3 @@ fn make_scopes() -> Scopes {
         | Scopes::write(scopes::Write::Media)
         | Scopes::write(scopes::Write::Follows)
 }
-
-// trait TapOk<T> {
-//     fn tap_ok<F: FnOnce(&T)>(self, f: F) -> Self;
-// }
-//
-// impl<T, E> TapOk<T> for Result<T, E> {
-//     fn tap_ok<F: FnOnce(&T)>(self, f: F) -> Self {
-//         match self {
-//             Ok(v) => {
-//                 f(&v);
-//                 Ok(v)
-//             }
-//             Err(e) => Err(e)
-//         }
-//     }
-// }