Added @all handler for groups

Signed-off-by: Pavel Kirilin <win10@list.ru>

src/bot/handlers/basic/mod.rs

@@ -1,4 +1,5 @@
 pub mod currency_converter;
 pub mod get_chat_id;
 pub mod help;
+pub mod notify_all;
 pub mod weather_forecaster;

src/bot/handlers/basic/notify_all.rs

@@ -0,0 +1,28 @@
+use grammers_client::{types::Chat, Client, Update};
+
+use crate::{bot::handlers::Handler, utils::messages::get_message};
+
+#[derive(Clone)]
+pub struct NotifyAll;
+
+#[async_trait::async_trait]
+impl Handler for NotifyAll {
+    async fn react(&self, client: &Client, update: &Update) -> anyhow::Result<()> {
+        let Some(message) = get_message(update) else {return Ok(());};
+        let Chat::Group(group) = message.chat() else {
+            return Ok(());
+        };
+        let mut participats_iter = client.iter_participants(group);
+        let mut response = String::new();
+        while let Some(participant) = participats_iter.next().await? {
+            if participant.user.is_bot() {
+                continue;
+            }
+            if let Some(username) = participant.user.username() {
+                response.push_str(format!("@{username} ").as_str());
+            }
+        }
+        message.reply(response).await?;
+        Ok(())
+    }
+}