From 461e1150e59bca46eed7b9168ecd6273f60edd69 Mon Sep 17 00:00:00 2001
From: Temirkhan Myrzamadi <hirrolot@gmail.com>
Date: Thu, 30 Jul 2020 18:54:48 +0600
Subject: [PATCH] Add dispatching::repl

---
 CHANGELOG.md            |  4 ++--
 src/dispatching/mod.rs  |  2 ++
 src/dispatching/repl.rs | 40 ++++++++++++++++++++++++++++++++++++++++
 src/prelude.rs          |  2 +-
 4 files changed, 45 insertions(+), 3 deletions(-)
 create mode 100644 src/dispatching/repl.rs

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0b6be63f..fc4ed1d1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,11 +16,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  - The `frunk` feature -- enables `teloxide::utils::UpState`, which allows mapping from a structure of `field1, ..., fieldN` to a structure of `field1, ..., fieldN, fieldN+1`.
  - Upgrade to v4.9 Telegram bots API.
  - `teloxide::utils::client_from_env` -- constructs a client from the `TELOXIDE_TOKEN` environmental variable.
- - Import `Transition`, `TransitionIn`, `TransitionOut`, `UpState` to `teloxide::prelude`.
+ - Import `Transition`, `TransitionIn`, `TransitionOut`, `UpState`, `repl` to `teloxide::prelude`.
  - Let users inspect an unknown API error using `ApiErrorKind::Unknown(String)`. All the known API errors are placed into `KnownApiErrorKind`.
  - Setters to all the API types.
  - `teloxide::dispatching::dialogue::serializer` -- various serializers for memory storages. The `Serializer` trait, `Bincode`, `CBOR`, `JSON`.
-
+ - `teloxide::dispatching::repl`
 
 ### Deprecated
  - `Bot::{from_env_with_client, new, with_client}`
diff --git a/src/dispatching/mod.rs b/src/dispatching/mod.rs
index 320ae5dc..a99c954e 100644
--- a/src/dispatching/mod.rs
+++ b/src/dispatching/mod.rs
@@ -78,12 +78,14 @@ pub mod dialogue;
 mod dispatcher;
 mod dispatcher_handler;
 mod dispatcher_handler_rx_ext;
+mod repl;
 pub mod update_listeners;
 mod update_with_cx;
 
 pub use dispatcher::Dispatcher;
 pub use dispatcher_handler::DispatcherHandler;
 pub use dispatcher_handler_rx_ext::DispatcherHandlerRxExt;
+pub use repl::repl;
 use tokio::sync::mpsc::UnboundedReceiver;
 pub use update_with_cx::UpdateWithCx;
 
diff --git a/src/dispatching/repl.rs b/src/dispatching/repl.rs
new file mode 100644
index 00000000..d138f402
--- /dev/null
+++ b/src/dispatching/repl.rs
@@ -0,0 +1,40 @@
+use crate::{
+    dispatching::{Dispatcher, DispatcherHandlerRx, UpdateWithCx},
+    error_handlers::OnError,
+    requests::ResponseResult,
+    types::Message,
+    Bot,
+};
+use futures::StreamExt;
+use std::{future::Future, sync::Arc};
+
+/// A [REPL] for messages.
+///
+/// Used mostly for testing and demonstrative purposes.
+///
+/// # Caution
+/// **DO NOT** use this function together with [`Dispatcher`], because Telegram
+/// disallow multiple requests at the same time from the same bot.
+///
+/// [REPL]: https://en.wikipedia.org/wiki/Read-eval-print_loop
+/// [`Dispatcher`]: crate::dispatching::Dispatcher
+pub async fn repl<H, Fut>(bot: Bot, handler: H)
+where
+    H: Fn(UpdateWithCx<Message>) -> Fut + Send + Sync + 'static,
+    Fut: Future<Output = ResponseResult<()>> + Send + 'static,
+{
+    let handler = Arc::new(handler);
+
+    Dispatcher::new(bot)
+        .messages_handler(|rx: DispatcherHandlerRx<Message>| {
+            rx.for_each_concurrent(None, move |message| {
+                let handler = Arc::clone(&handler);
+
+                async move {
+                    handler(message).await.log_on_error().await;
+                }
+            })
+        })
+        .dispatch()
+        .await;
+}
diff --git a/src/prelude.rs b/src/prelude.rs
index 3b2032d9..ee244451 100644
--- a/src/prelude.rs
+++ b/src/prelude.rs
@@ -6,7 +6,7 @@ pub use crate::{
             exit, next, DialogueDispatcher, DialogueStage, DialogueWithCx, GetChatId, Transition,
             TransitionIn, TransitionOut,
         },
-        Dispatcher, DispatcherHandlerRx, DispatcherHandlerRxExt, UpdateWithCx,
+        repl, Dispatcher, DispatcherHandlerRx, DispatcherHandlerRxExt, UpdateWithCx,
     },
     error_handlers::{LoggingErrorHandler, OnError},
     requests::{Request, ResponseResult},