// Copyright 2020, The Tari Project
//
// Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
// following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
// disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
// following disclaimer in the documentation and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote
// products derived from this software without specific prior written permission.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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// USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

use std::{
    future::Future,
    pin::Pin,
    task::{Context, Poll},
};

use futures::{FutureExt, future, future::JoinAll};
use tari_shutdown::ShutdownSignal;

/// Future which resolves once comms has shut down
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct CommsShutdown {
    signals: JoinAll<ShutdownSignal>,
}

impl CommsShutdown {
    pub fn new<I>(triggers: I) -> Self
    where I: IntoIterator<Item = ShutdownSignal> {
        Self {
            signals: future::join_all(triggers),
        }
    }
}

impl Future for CommsShutdown {
    type Output = ();

    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        let _result = futures::ready!(self.signals.poll_unpin(cx));
        Poll::Ready(())
    }
}
