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use crate::backend::GenericSocketBackend;
use crate::codec::*;
use crate::endpoint::Endpoint;
use crate::error::{ZmqError, ZmqResult};
use crate::fair_queue::FairQueue;
use crate::message::*;
use crate::transport::AcceptStopHandle;
use crate::util::PeerIdentity;
use crate::{MultiPeerBackend, SocketEvent, SocketOptions, SocketRecv, SocketSend, SocketType};
use crate::{Socket, SocketBackend};

use async_trait::async_trait;
use futures_channel::mpsc;
use futures_util::{SinkExt, StreamExt};

use std::collections::HashMap;
use std::convert::TryInto;
use std::sync::Arc;

pub struct RouterSocket {
    backend: Arc<GenericSocketBackend>,
    binds: HashMap<Endpoint, AcceptStopHandle>,
    fair_queue: FairQueue<ZmqFramedRead, PeerIdentity>,
}

impl Drop for RouterSocket {
    fn drop(&mut self) {
        self.backend.shutdown();
    }
}

#[async_trait]
impl Socket for RouterSocket {
    fn with_options(options: SocketOptions) -> Self {
        let fair_queue = FairQueue::new(true);
        Self {
            backend: Arc::new(GenericSocketBackend::with_options(
                Some(fair_queue.inner()),
                SocketType::ROUTER,
                options,
            )),
            binds: HashMap::new(),
            fair_queue,
        }
    }

    fn backend(&self) -> Arc<dyn MultiPeerBackend> {
        self.backend.clone()
    }

    fn binds(&mut self) -> &mut HashMap<Endpoint, AcceptStopHandle> {
        &mut self.binds
    }

    fn monitor(&mut self) -> mpsc::Receiver<SocketEvent> {
        let (sender, receiver) = mpsc::channel(1024);
        self.backend.socket_monitor.lock().replace(sender);
        receiver
    }
}

#[async_trait]
impl SocketRecv for RouterSocket {
    async fn recv(&mut self) -> ZmqResult<ZmqMessage> {
        loop {
            match self.fair_queue.next().await {
                Some((peer_id, Ok(Message::Message(mut message)))) => {
                    message.push_front(peer_id.into());
                    return Ok(message);
                }
                Some((_peer_id, Ok(msg))) => todo!("Unimplemented message: {:?}", msg),
                Some((peer_id, Err(_))) => {
                    self.backend.peer_disconnected(&peer_id);
                }
                None => todo!(),
            };
        }
    }
}

#[async_trait]
impl SocketSend for RouterSocket {
    async fn send(&mut self, mut message: ZmqMessage) -> ZmqResult<()> {
        assert!(message.len() > 1);
        let peer_id: PeerIdentity = message.pop_front().unwrap().try_into()?;
        match self.backend.peers.get_mut(&peer_id) {
            Some(mut peer) => {
                peer.send_queue.send(Message::Message(message)).await?;
                Ok(())
            }
            None => Err(ZmqError::Other("Destination client not found by identity")),
        }
    }
}