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// Copyright 2022 Protocol Labs.
// Copyright 2018 Parity Technologies (UK) 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 crate::handler::{
    ConnectionEvent, ConnectionHandler, ConnectionHandlerEvent, FullyNegotiatedInbound,
    FullyNegotiatedOutbound, KeepAlive, SubstreamProtocol,
};
use libp2p_core::upgrade::PendingUpgrade;
use std::task::{Context, Poll};
use void::Void;

/// Implementation of [`ConnectionHandler`] that returns a pending upgrade.
#[derive(Clone, Debug)]
pub struct PendingConnectionHandler {
    protocol_name: String,
}

impl PendingConnectionHandler {
    pub fn new(protocol_name: String) -> Self {
        PendingConnectionHandler { protocol_name }
    }
}

impl ConnectionHandler for PendingConnectionHandler {
    type InEvent = Void;
    type OutEvent = Void;
    type Error = Void;
    type InboundProtocol = PendingUpgrade<String>;
    type OutboundProtocol = PendingUpgrade<String>;
    type OutboundOpenInfo = Void;
    type InboundOpenInfo = ();

    fn listen_protocol(&self) -> SubstreamProtocol<Self::InboundProtocol, Self::InboundOpenInfo> {
        SubstreamProtocol::new(PendingUpgrade::new(self.protocol_name.clone()), ())
    }

    fn on_behaviour_event(&mut self, v: Self::InEvent) {
        void::unreachable(v)
    }

    fn connection_keep_alive(&self) -> KeepAlive {
        KeepAlive::No
    }

    fn poll(
        &mut self,
        _: &mut Context<'_>,
    ) -> Poll<
        ConnectionHandlerEvent<
            Self::OutboundProtocol,
            Self::OutboundOpenInfo,
            Self::OutEvent,
            Self::Error,
        >,
    > {
        Poll::Pending
    }

    fn on_connection_event(
        &mut self,
        event: ConnectionEvent<
            Self::InboundProtocol,
            Self::OutboundProtocol,
            Self::InboundOpenInfo,
            Self::OutboundOpenInfo,
        >,
    ) {
        match event {
            ConnectionEvent::FullyNegotiatedInbound(FullyNegotiatedInbound {
                protocol, ..
            }) => void::unreachable(protocol),
            ConnectionEvent::FullyNegotiatedOutbound(FullyNegotiatedOutbound {
                protocol,
                info: _info,
            }) => {
                void::unreachable(protocol);
                #[allow(unreachable_code)]
                {
                    void::unreachable(_info);
                }
            }
            ConnectionEvent::AddressChange(_)
            | ConnectionEvent::DialUpgradeError(_)
            | ConnectionEvent::ListenUpgradeError(_) => {}
        }
    }
}