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// Copyright 2020 Netwarps Ltd.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

use futures::{
    channel::{mpsc, oneshot},
    SinkExt,
};

use crate::{
    connection::{stream::Stream, ControlCommand},
    error::ConnectionError,
};

pub struct Control {
    sender: mpsc::Sender<ControlCommand>,
}

type Result<T> = std::result::Result<T, ConnectionError>;

impl Control {
    pub fn new(sender: mpsc::Sender<ControlCommand>) -> Self {
        Control { sender }
    }

    /// Open a new stream to the remote.
    pub async fn open_stream(&mut self) -> Result<Stream> {
        let (tx, rx) = oneshot::channel();
        self.sender.send(ControlCommand::OpenStream(tx)).await?;
        rx.await?
    }

    /// Accept a new stream from the remote.
    pub async fn accept_stream(&mut self) -> Result<Stream> {
        let (tx, rx) = oneshot::channel();
        self.sender.send(ControlCommand::AcceptStream(tx)).await?;
        rx.await?
    }

    /// Close the connection.
    pub async fn close(&mut self) -> Result<()> {
        let (tx, rx) = oneshot::channel();
        if self.sender.send(ControlCommand::CloseConnection(tx)).await.is_err() {
            // The receiver is closed which means the connection is already closed.
            return Ok(());
        }
        // A dropped `oneshot::Sender` means the `Connection` is gone,
        // so we do not treat receive errors differently here.
        let _ = rx.await;
        Ok(())
    }
}

impl Clone for Control {
    fn clone(&self) -> Self {
        Control {
            sender: self.sender.clone(),
        }
    }
}