From 94c4955c4928fde38e394e3200cfb41185c5891f Mon Sep 17 00:00:00 2001
From: LasterAlex <sasha.ishukshin@gmail.com>
Date: Sat, 17 Aug 2024 22:45:27 +0300
Subject: [PATCH] Added bot_mention_command filter

---
 CHANGELOG.md                                  |  1 +
 crates/teloxide/src/dispatching.rs            |  2 +-
 .../teloxide/src/dispatching/handler_ext.rs   | 54 +++++++++++++++++++
 crates/teloxide/src/lib.rs                    |  2 +-
 4 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3b993d45..deae0c9a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Add `filter_boost_added` and `filter_reply_to_story` filters to `MessageFilterExt` trait
+- Add `filter_mention_command` filter to `HandlerExt` trait ([issue #494](https://github.com/teloxide/teloxide/issues/494))
 
 ## 0.13.0 - 2024-08-16
 
diff --git a/crates/teloxide/src/dispatching.rs b/crates/teloxide/src/dispatching.rs
index 1caa197b..1d16b35a 100644
--- a/crates/teloxide/src/dispatching.rs
+++ b/crates/teloxide/src/dispatching.rs
@@ -227,4 +227,4 @@ pub use dispatcher::{Dispatcher, DispatcherBuilder, UpdateHandler};
 pub use distribution::DefaultKey;
 pub use filter_ext::{MessageFilterExt, UpdateFilterExt};
 pub use handler_description::DpHandlerDescription;
-pub use handler_ext::{filter_command, HandlerExt};
+pub use handler_ext::{filter_command, filter_mention_command, HandlerExt};
diff --git a/crates/teloxide/src/dispatching/handler_ext.rs b/crates/teloxide/src/dispatching/handler_ext.rs
index f5f3236d..df808e29 100644
--- a/crates/teloxide/src/dispatching/handler_ext.rs
+++ b/crates/teloxide/src/dispatching/handler_ext.rs
@@ -23,6 +23,18 @@ pub trait HandlerExt<Output> {
     where
         C: BotCommands + Send + Sync + 'static;
 
+    /// Returns a handler that accepts a parsed command `C` if the command
+    /// contains a bot mention, for example `/start@my_bot`.
+    ///
+    /// ## Dependency requirements
+    ///
+    ///  - [`crate::types::Message`]
+    ///  - [`crate::types::Me`]
+    #[must_use]
+    fn filter_mention_command<C>(self) -> Self
+    where
+        C: BotCommands + Send + Sync + 'static;
+
     /// Passes [`Dialogue<D, S>`] and `D` as handler dependencies.
     ///
     /// It does so by the following steps:
@@ -61,6 +73,13 @@ where
         self.chain(filter_command::<C, Output>())
     }
 
+    fn filter_mention_command<C>(self) -> Self
+    where
+        C: BotCommands + Send + Sync + 'static,
+    {
+        self.chain(filter_mention_command::<C, Output>())
+    }
+
     fn enter_dialogue<Upd, S, D>(self) -> Self
     where
         S: Storage<D> + ?Sized + Send + Sync + 'static,
@@ -93,3 +112,38 @@ where
         message.text().and_then(|text| C::parse(text, &bot_name).ok())
     })
 }
+
+/// Returns a handler that accepts a parsed command `C` if the command
+/// contains a bot mention, for example `/start@my_bot`.
+///
+/// A call to this function is the same as
+/// `dptree::entry().filter_mention_command()`.
+///
+/// See [`HandlerExt::filter_mention_command`].
+///
+/// ## Dependency requirements
+///
+///  - [`crate::types::Message`]
+///  - [`crate::types::Me`]
+#[must_use]
+pub fn filter_mention_command<C, Output>(
+) -> Handler<'static, DependencyMap, Output, DpHandlerDescription>
+where
+    C: BotCommands + Send + Sync + 'static,
+    Output: Send + Sync + 'static,
+{
+    dptree::filter_map(move |message: Message, me: Me| {
+        let bot_name = me.user.username.expect("Bots must have a username");
+
+        let command = message.text().and_then(|text| C::parse(text, &bot_name).ok());
+        // If the parsing succeeds with a bot_name,
+        // but fails without - there is a mention
+        let is_username_required =
+            message.text().and_then(|text| C::parse(text, "").ok()).is_none();
+
+        if !is_username_required {
+            return None;
+        }
+        command
+    })
+}
diff --git a/crates/teloxide/src/lib.rs b/crates/teloxide/src/lib.rs
index f4c9995c..7a789398 100644
--- a/crates/teloxide/src/lib.rs
+++ b/crates/teloxide/src/lib.rs
@@ -149,7 +149,7 @@ pub use teloxide_core::*;
 #[cfg(feature = "macros")]
 pub use teloxide_macros as macros;
 
-pub use dispatching::filter_command;
+pub use dispatching::{filter_command, filter_mention_command};
 pub use dptree::{self, case as handler};
 
 #[cfg(all(feature = "nightly", doctest))]