Added support for groups being created with the bot in the initial group of members; fixed unhandled warnings when the bot leaves the group

src/main.rs

@@ -39,7 +39,6 @@ enum Command {
     #[command(description = "Show help.")]
     Help,
     // Fallback for an unknown command
-    /// Unknown command
     #[command(description = "Unknown command.")]
     Unknown(String),
 }
@@ -69,16 +68,34 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     //    A: new chat members,
     //    B: recognized commands (/start, /help, etc.)
     let handler = dptree::entry()
+    // 1) Branch A: the usual case for the bot being added after the group is created
         .branch(
             Update::filter_message()
                 .filter(|msg: Message| msg.new_chat_members().is_some())
                 .endpoint(handle_new_chat_members),
         )
+        // 2) Branch B: if the group is created with the bot already in it
+        .branch(
+            Update::filter_message()
+                .filter(|msg: Message| {
+                    // For newly created group
+                    msg.group_chat_created().is_some() 
+                        // Or newly created supergroup
+                        || msg.super_group_chat_created().is_some()
+                })
+                .endpoint(handle_group_created),
+        )
+        // 3) Commands etc.:
         .branch(
             Update::filter_message()
-                // parse the text into Command
                 .filter_command::<Command>()
                 .endpoint(handle_commands),
+        )
+        // 4) User leaves group/chat
+        .branch(
+            Update::filter_message()
+                .filter(|msg: Message| msg.left_chat_member().is_some())
+                .endpoint(handle_left_chat_member),
         );
 
     // 6) Launch the dispatcher
@@ -121,6 +138,45 @@ async fn handle_new_chat_members(bot: Bot, msg: Message) -> Result<(), teloxide:
     Ok(())
 }
 
+/// Detect if a new group is created with the bot as a founding member, say the group ID, then leave.
+async fn handle_group_created(bot: Bot, msg: Message) -> Result<(), teloxide::RequestError> {
+    // Same logic as if the bot was added:
+    let chat_id = msg.chat.id;
+
+    // Post the group’s chat ID
+    bot.send_message(chat_id, format!("Group Chat ID is: {chat_id}")).await?;
+
+    // Optionally log the event
+    log::info!(
+        "Bot was in a newly created group (chatID: {}). Posting ID and leaving...",
+        chat_id
+    );
+
+    // Leave the group
+    bot.leave_chat(chat_id).await?;
+
+    Ok(())
+}
+
+/// Handle "left chat member" events so they are not generating WARN statements. These events will happen almost every time the bot is used.
+async fn handle_left_chat_member(
+    msg: Message,
+) -> Result<(), teloxide::RequestError> {
+    // Telegram sets this field if a user (or the bot) left.
+    if let Some(left_user) = msg.left_chat_member() {
+        log::info!(
+            "User/bot @{} (ID {}) left the chat {}",
+            left_user.username.clone().unwrap_or_default(),
+            left_user.id,
+            msg.chat.id
+        );
+
+        // Optionally do something else, like sending a "goodbye" message?
+        // For now, we'll just swallow this event so it won't be "unhandled".
+    }
+    Ok(())
+}
+
 /// Handle commands in private chat
 async fn handle_commands(
     bot: Bot,