pure-stage 0.1.1

// Copyright 2025 PRAGMA
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::{fmt, sync::Arc};

use crate::BoxFuture;

/// A handle for sending messages to a stage from outside the simulation.
///
/// Such a handle is obtained using [`StageGraph::input`](crate::StageGraph::input).
pub struct Sender<Msg> {
    tx: Arc<dyn Fn(Msg) -> BoxFuture<'static, Result<(), Msg>> + Send + Sync>,
}

impl<Msg> Clone for Sender<Msg> {
    fn clone(&self) -> Self {
        Self { tx: self.tx.clone() }
    }
}

impl<Msg> fmt::Debug for Sender<Msg> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Sender").field("Msg", &std::any::type_name::<Msg>()).finish()
    }
}

impl<Msg> Sender<Msg> {
    pub(crate) fn new(tx: Arc<dyn Fn(Msg) -> BoxFuture<'static, Result<(), Msg>> + Send + Sync>) -> Self {
        Self { tx }
    }

    pub fn send(&self, msg: Msg) -> BoxFuture<'static, Result<(), Msg>> {
        (self.tx)(msg)
    }
}