use crate::{
	inner::WsEvent,
	sink_unfold,
	ws::{Frame, LockedWebSocketWrite, Payload},
	AtomicCloseReason, CloseReason, Packet, Role, StreamType, WispError,
};

use bytes::{BufMut, Bytes, BytesMut};
use event_listener::Event;
use flume as mpsc;
use futures::{
	channel::oneshot,
	ready, select,
	stream::{self, IntoAsyncRead},
	task::{noop_waker_ref, Context, Poll},
	AsyncBufRead, AsyncRead, AsyncWrite, FutureExt, Sink, Stream, TryStreamExt,
};
use pin_project_lite::pin_project;
use std::{
	pin::Pin,
	sync::{
		atomic::{AtomicBool, AtomicU32, Ordering},
		Arc,
	},
};

/// Read side of a multiplexor stream.
pub struct MuxStreamRead {
	/// ID of the stream.
	pub stream_id: u32,
	/// Type of the stream.
	pub stream_type: StreamType,

	role: Role,

	tx: LockedWebSocketWrite,
	rx: mpsc::Receiver<Bytes>,

	is_closed: Arc<AtomicBool>,
	is_closed_event: Arc<Event>,
	close_reason: Arc<AtomicCloseReason>,

	should_flow_control: bool,
	flow_control: Arc<AtomicU32>,
	flow_control_read: AtomicU32,
	target_flow_control: u32,
}

impl MuxStreamRead {
	/// Read an event from the stream.
	pub async fn read(&self) -> Option<Bytes> {
		if self.is_closed.load(Ordering::Acquire) {
			return None;
		}
		let bytes = select! {
			x = self.rx.recv_async() => x.ok()?,
			_ = self.is_closed_event.listen().fuse() => return None
		};
		if self.role == Role::Server && self.should_flow_control {
			let val = self.flow_control_read.fetch_add(1, Ordering::AcqRel) + 1;
			if val > self.target_flow_control && !self.is_closed.load(Ordering::Acquire) {
				self.tx
					.write_frame(
						Packet::new_continue(
							self.stream_id,
							self.flow_control.fetch_add(val, Ordering::AcqRel) + val,
						)
						.into(),
					)
					.await
					.ok()?;
				self.flow_control_read.store(0, Ordering::Release);
			}
		}
		Some(bytes)
	}

	pub(crate) fn into_inner_stream(self) -> Pin<Box<dyn Stream<Item = Bytes> + Send>> {
		Box::pin(stream::unfold(self, |rx| async move {
			Some((rx.read().await?, rx))
		}))
	}

	/// Turn the read half into one that implements futures `Stream`, consuming it.
	pub fn into_stream(self) -> MuxStreamIoStream {
		MuxStreamIoStream {
			close_reason: self.close_reason.clone(),
			is_closed: self.is_closed.clone(),
			rx: self.into_inner_stream(),
		}
	}

	/// Get the stream's close reason, if it was closed.
	pub fn get_close_reason(&self) -> Option<CloseReason> {
		if self.is_closed.load(Ordering::Acquire) {
			Some(self.close_reason.load(Ordering::Acquire))
		} else {
			None
		}
	}
}

/// Write side of a multiplexor stream.
pub struct MuxStreamWrite {
	/// ID of the stream.
	pub stream_id: u32,
	/// Type of the stream.
	pub stream_type: StreamType,

	role: Role,
	mux_tx: mpsc::Sender<WsEvent>,
	tx: LockedWebSocketWrite,

	is_closed: Arc<AtomicBool>,
	close_reason: Arc<AtomicCloseReason>,

	continue_recieved: Arc<Event>,
	should_flow_control: bool,
	flow_control: Arc<AtomicU32>,
}

impl MuxStreamWrite {
	pub(crate) async fn write_payload_internal<'a>(
		&self,
		header: Frame<'static>,
		body: Frame<'a>,
	) -> Result<(), WispError> {
		if self.role == Role::Client
			&& self.should_flow_control
			&& self.flow_control.load(Ordering::Acquire) == 0
		{
			self.continue_recieved.listen().await;
		}
		if self.is_closed.load(Ordering::Acquire) {
			return Err(WispError::StreamAlreadyClosed);
		}

		self.tx.write_split(header, body).await?;

		if self.role == Role::Client && self.stream_type == StreamType::Tcp {
			self.flow_control.store(
				self.flow_control.load(Ordering::Acquire).saturating_sub(1),
				Ordering::Release,
			);
		}
		Ok(())
	}

	/// Write a payload to the stream.
	pub async fn write_payload(&self, data: Payload<'_>) -> Result<(), WispError> {
		let frame: Frame<'static> = Frame::from(Packet::new_data(
			self.stream_id,
			Payload::Bytes(BytesMut::new()),
		));
		self.write_payload_internal(frame, Frame::binary(data))
			.await
	}

	/// Write data to the stream.
	pub async fn write<D: AsRef<[u8]>>(&self, data: D) -> Result<(), WispError> {
		self.write_payload(Payload::Borrowed(data.as_ref())).await
	}

	/// Get a handle to close the connection.
	///
	/// Useful to close the connection without having access to the stream.
	///
	/// # Example
	/// ```
	/// let handle = stream.get_close_handle();
	/// if let Err(error) = handle_stream(stream) {
	///     handle.close(0x01);
	/// }
	/// ```
	pub fn get_close_handle(&self) -> MuxStreamCloser {
		MuxStreamCloser {
			stream_id: self.stream_id,
			close_channel: self.mux_tx.clone(),
			is_closed: self.is_closed.clone(),
			close_reason: self.close_reason.clone(),
		}
	}

	/// Get a protocol extension stream to send protocol extension packets.
	pub fn get_protocol_extension_stream(&self) -> MuxProtocolExtensionStream {
		MuxProtocolExtensionStream {
			stream_id: self.stream_id,
			tx: self.tx.clone(),
			is_closed: self.is_closed.clone(),
		}
	}

	/// Close the stream. You will no longer be able to write or read after this has been called.
	pub async fn close(&self, reason: CloseReason) -> Result<(), WispError> {
		if self.is_closed.load(Ordering::Acquire) {
			return Err(WispError::StreamAlreadyClosed);
		}
		self.is_closed.store(true, Ordering::Release);

		let (tx, rx) = oneshot::channel::<Result<(), WispError>>();
		self.mux_tx
			.send_async(WsEvent::Close(
				Packet::new_close(self.stream_id, reason),
				tx,
			))
			.await
			.map_err(|_| WispError::MuxMessageFailedToSend)?;
		rx.await.map_err(|_| WispError::MuxMessageFailedToRecv)??;

		Ok(())
	}

	/// Get the stream's close reason, if it was closed.
	pub fn get_close_reason(&self) -> Option<CloseReason> {
		if self.is_closed.load(Ordering::Acquire) {
			Some(self.close_reason.load(Ordering::Acquire))
		} else {
			None
		}
	}

	pub(crate) fn into_inner_sink(
		self,
	) -> Pin<Box<dyn Sink<Payload<'static>, Error = WispError> + Send>> {
		let handle = self.get_close_handle();
		Box::pin(sink_unfold::unfold(
			self,
			|tx, data| async move {
				tx.write_payload(data).await?;
				Ok(tx)
			},
			handle,
			|handle| async move {
				handle.close(CloseReason::Unknown).await?;
				Ok(handle)
			},
		))
	}

	/// Turn the write half into one that implements futures `Sink`, consuming it.
	pub fn into_sink(self) -> MuxStreamIoSink {
		MuxStreamIoSink {
			close_reason: self.close_reason.clone(),
			is_closed: self.is_closed.clone(),
			tx: self.into_inner_sink(),
		}
	}
}

impl Drop for MuxStreamWrite {
	fn drop(&mut self) {
		if !self.is_closed.load(Ordering::Acquire) {
			self.is_closed.store(true, Ordering::Release);
			let (tx, _) = oneshot::channel();
			let _ = self.mux_tx.send(WsEvent::Close(
				Packet::new_close(self.stream_id, CloseReason::Unknown),
				tx,
			));
		}
	}
}

/// Multiplexor stream.
pub struct MuxStream {
	/// ID of the stream.
	pub stream_id: u32,
	rx: MuxStreamRead,
	tx: MuxStreamWrite,
}

impl MuxStream {
	#[allow(clippy::too_many_arguments)]
	pub(crate) fn new(
		stream_id: u32,
		role: Role,
		stream_type: StreamType,
		rx: mpsc::Receiver<Bytes>,
		mux_tx: mpsc::Sender<WsEvent>,
		tx: LockedWebSocketWrite,
		is_closed: Arc<AtomicBool>,
		is_closed_event: Arc<Event>,
		close_reason: Arc<AtomicCloseReason>,
		should_flow_control: bool,
		flow_control: Arc<AtomicU32>,
		continue_recieved: Arc<Event>,
		target_flow_control: u32,
	) -> Self {
		Self {
			stream_id,
			rx: MuxStreamRead {
				stream_id,
				stream_type,
				role,
				tx: tx.clone(),
				rx,
				is_closed: is_closed.clone(),
				is_closed_event: is_closed_event.clone(),
				close_reason: close_reason.clone(),
				should_flow_control,
				flow_control: flow_control.clone(),
				flow_control_read: AtomicU32::new(0),
				target_flow_control,
			},
			tx: MuxStreamWrite {
				stream_id,
				stream_type,
				role,
				mux_tx,
				tx,
				is_closed: is_closed.clone(),
				close_reason: close_reason.clone(),
				should_flow_control,
				flow_control: flow_control.clone(),
				continue_recieved: continue_recieved.clone(),
			},
		}
	}

	/// Read an event from the stream.
	pub async fn read(&self) -> Option<Bytes> {
		self.rx.read().await
	}

	/// Write a payload to the stream.
	pub async fn write_payload(&self, data: Payload<'_>) -> Result<(), WispError> {
		self.tx.write_payload(data).await
	}

	/// Write data to the stream.
	pub async fn write<D: AsRef<[u8]>>(&self, data: D) -> Result<(), WispError> {
		self.tx.write(data).await
	}

	/// Get a handle to close the connection.
	///
	/// Useful to close the connection without having access to the stream.
	///
	/// # Example
	/// ```
	/// let handle = stream.get_close_handle();
	/// if let Err(error) = handle_stream(stream) {
	///     handle.close(0x01);
	/// }
	/// ```
	pub fn get_close_handle(&self) -> MuxStreamCloser {
		self.tx.get_close_handle()
	}

	/// Get a protocol extension stream to send protocol extension packets.
	pub fn get_protocol_extension_stream(&self) -> MuxProtocolExtensionStream {
		self.tx.get_protocol_extension_stream()
	}

	/// Get the stream's close reason, if it was closed.
	pub fn get_close_reason(&self) -> Option<CloseReason> {
		self.rx.get_close_reason()
	}

	/// Close the stream. You will no longer be able to write or read after this has been called.
	pub async fn close(&self, reason: CloseReason) -> Result<(), WispError> {
		self.tx.close(reason).await
	}

	/// Split the stream into read and write parts, consuming it.
	pub fn into_split(self) -> (MuxStreamRead, MuxStreamWrite) {
		(self.rx, self.tx)
	}

	/// Turn the stream into one that implements futures `Stream + Sink`, consuming it.
	pub fn into_io(self) -> MuxStreamIo {
		MuxStreamIo {
			rx: self.rx.into_stream(),
			tx: self.tx.into_sink(),
		}
	}
}

/// Close handle for a multiplexor stream.
#[derive(Clone)]
pub struct MuxStreamCloser {
	/// ID of the stream.
	pub stream_id: u32,
	close_channel: mpsc::Sender<WsEvent>,
	is_closed: Arc<AtomicBool>,
	close_reason: Arc<AtomicCloseReason>,
}

impl MuxStreamCloser {
	/// Close the stream. You will no longer be able to write or read after this has been called.
	pub async fn close(&self, reason: CloseReason) -> Result<(), WispError> {
		if self.is_closed.load(Ordering::Acquire) {
			return Err(WispError::StreamAlreadyClosed);
		}
		self.is_closed.store(true, Ordering::Release);

		let (tx, rx) = oneshot::channel::<Result<(), WispError>>();
		self.close_channel
			.send_async(WsEvent::Close(
				Packet::new_close(self.stream_id, reason),
				tx,
			))
			.await
			.map_err(|_| WispError::MuxMessageFailedToSend)?;
		rx.await.map_err(|_| WispError::MuxMessageFailedToRecv)??;

		Ok(())
	}

	/// Get the stream's close reason, if it was closed.
	pub fn get_close_reason(&self) -> Option<CloseReason> {
		if self.is_closed.load(Ordering::Acquire) {
			Some(self.close_reason.load(Ordering::Acquire))
		} else {
			None
		}
	}
}

/// Stream for sending arbitrary protocol extension packets.
pub struct MuxProtocolExtensionStream {
	/// ID of the stream.
	pub stream_id: u32,
	pub(crate) tx: LockedWebSocketWrite,
	pub(crate) is_closed: Arc<AtomicBool>,
}

impl MuxProtocolExtensionStream {
	/// Send a protocol extension packet with this stream's ID.
	pub async fn send(&self, packet_type: u8, data: Bytes) -> Result<(), WispError> {
		if self.is_closed.load(Ordering::Acquire) {
			return Err(WispError::StreamAlreadyClosed);
		}
		let mut encoded = BytesMut::with_capacity(1 + 4 + data.len());
		encoded.put_u8(packet_type);
		encoded.put_u32_le(self.stream_id);
		encoded.extend(data);
		self.tx
			.write_frame(Frame::binary(Payload::Bytes(encoded)))
			.await
	}
}

pin_project! {
	/// Multiplexor stream that implements futures `Stream + Sink`.
	pub struct MuxStreamIo {
		#[pin]
		rx: MuxStreamIoStream,
		#[pin]
		tx: MuxStreamIoSink,
	}
}

impl MuxStreamIo {
	/// Turn the stream into one that implements futures `AsyncRead + AsyncBufRead + AsyncWrite`.
	pub fn into_asyncrw(self) -> MuxStreamAsyncRW {
		MuxStreamAsyncRW {
			rx: self.rx.into_asyncread(),
			tx: self.tx.into_asyncwrite(),
		}
	}

	/// Get the stream's close reason, if it was closed.
	pub fn get_close_reason(&self) -> Option<CloseReason> {
		self.rx.get_close_reason()
	}

	/// Split the stream into read and write parts, consuming it.
	pub fn into_split(self) -> (MuxStreamIoStream, MuxStreamIoSink) {
		(self.rx, self.tx)
	}
}

impl Stream for MuxStreamIo {
	type Item = Result<Bytes, std::io::Error>;
	fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
		self.project().rx.poll_next(cx)
	}
}

impl Sink<&[u8]> for MuxStreamIo {
	type Error = std::io::Error;
	fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
		self.project().tx.poll_ready(cx)
	}
	fn start_send(self: Pin<&mut Self>, item: &[u8]) -> Result<(), Self::Error> {
		self.project().tx.start_send(item)
	}
	fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
		self.project().tx.poll_flush(cx)
	}
	fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
		self.project().tx.poll_close(cx)
	}
}

pin_project! {
	/// Read side of a multiplexor stream that implements futures `Stream`.
	pub struct MuxStreamIoStream {
		#[pin]
		rx: Pin<Box<dyn Stream<Item = Bytes> + Send>>,
		is_closed: Arc<AtomicBool>,
		close_reason: Arc<AtomicCloseReason>,
	}
}

impl MuxStreamIoStream {
	/// Turn the stream into one that implements futures `AsyncRead + AsyncBufRead`.
	pub fn into_asyncread(self) -> MuxStreamAsyncRead {
		MuxStreamAsyncRead::new(self)
	}

	/// Get the stream's close reason, if it was closed.
	pub fn get_close_reason(&self) -> Option<CloseReason> {
		if self.is_closed.load(Ordering::Acquire) {
			Some(self.close_reason.load(Ordering::Acquire))
		} else {
			None
		}
	}
}

impl Stream for MuxStreamIoStream {
	type Item = Result<Bytes, std::io::Error>;
	fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
		self.project().rx.poll_next(cx).map(|x| x.map(Ok))
	}
}

pin_project! {
	/// Write side of a multiplexor stream that implements futures `Sink`.
	pub struct MuxStreamIoSink {
		#[pin]
		tx: Pin<Box<dyn Sink<Payload<'static>, Error = WispError> + Send>>,
		is_closed: Arc<AtomicBool>,
		close_reason: Arc<AtomicCloseReason>,
	}
}

impl MuxStreamIoSink {
	/// Turn the sink into one that implements futures `AsyncWrite`.
	pub fn into_asyncwrite(self) -> MuxStreamAsyncWrite {
		MuxStreamAsyncWrite::new(self)
	}

	/// Get the stream's close reason, if it was closed.
	pub fn get_close_reason(&self) -> Option<CloseReason> {
		if self.is_closed.load(Ordering::Acquire) {
			Some(self.close_reason.load(Ordering::Acquire))
		} else {
			None
		}
	}
}

impl Sink<BytesMut> for MuxStreamIoSink {
	type Error = std::io::Error;
	fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
		self.project()
			.tx
			.poll_ready(cx)
			.map_err(std::io::Error::other)
	}
	fn start_send(self: Pin<&mut Self>, item: BytesMut) -> Result<(), Self::Error> {
		self.project()
			.tx
			.start_send(Payload::Bytes(item))
			.map_err(std::io::Error::other)
	}
	fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
		self.project()
			.tx
			.poll_flush(cx)
			.map_err(std::io::Error::other)
	}
	fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
		self.project()
			.tx
			.poll_close(cx)
			.map_err(std::io::Error::other)
	}
}

pin_project! {
	/// Multiplexor stream that implements futures `AsyncRead + AsyncBufRead + AsyncWrite`.
	pub struct MuxStreamAsyncRW {
		#[pin]
		rx: MuxStreamAsyncRead,
		#[pin]
		tx: MuxStreamAsyncWrite,
	}
}

impl MuxStreamAsyncRW {
	/// Get the stream's close reason, if it was closed.
	pub fn get_close_reason(&self) -> Option<CloseReason> {
		self.rx.get_close_reason()
	}

	/// Split the stream into read and write parts, consuming it.
	pub fn into_split(self) -> (MuxStreamAsyncRead, MuxStreamAsyncWrite) {
		(self.rx, self.tx)
	}
}

impl AsyncRead for MuxStreamAsyncRW {
	fn poll_read(
		self: Pin<&mut Self>,
		cx: &mut Context<'_>,
		buf: &mut [u8],
	) -> Poll<std::io::Result<usize>> {
		self.project().rx.poll_read(cx, buf)
	}

	fn poll_read_vectored(
		self: Pin<&mut Self>,
		cx: &mut Context<'_>,
		bufs: &mut [std::io::IoSliceMut<'_>],
	) -> Poll<std::io::Result<usize>> {
		self.project().rx.poll_read_vectored(cx, bufs)
	}
}

impl AsyncBufRead for MuxStreamAsyncRW {
	fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<&[u8]>> {
		self.project().rx.poll_fill_buf(cx)
	}

	fn consume(self: Pin<&mut Self>, amt: usize) {
		self.project().rx.consume(amt)
	}
}

impl AsyncWrite for MuxStreamAsyncRW {
	fn poll_write(
		self: Pin<&mut Self>,
		cx: &mut Context<'_>,
		buf: &[u8],
	) -> Poll<std::io::Result<usize>> {
		self.project().tx.poll_write(cx, buf)
	}

	fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
		self.project().tx.poll_flush(cx)
	}

	fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
		self.project().tx.poll_close(cx)
	}
}

pin_project! {
	/// Read side of a multiplexor stream that implements futures `AsyncRead + AsyncBufRead`.
	pub struct MuxStreamAsyncRead {
		#[pin]
		rx: IntoAsyncRead<MuxStreamIoStream>,
		is_closed: Arc<AtomicBool>,
		close_reason: Arc<AtomicCloseReason>,
	}
}

impl MuxStreamAsyncRead {
	pub(crate) fn new(stream: MuxStreamIoStream) -> Self {
		Self {
			is_closed: stream.is_closed.clone(),
			close_reason: stream.close_reason.clone(),
			rx: stream.into_async_read(),
		}
	}

	/// Get the stream's close reason, if it was closed.
	pub fn get_close_reason(&self) -> Option<CloseReason> {
		if self.is_closed.load(Ordering::Acquire) {
			Some(self.close_reason.load(Ordering::Acquire))
		} else {
			None
		}
	}
}

impl AsyncRead for MuxStreamAsyncRead {
	fn poll_read(
		self: Pin<&mut Self>,
		cx: &mut Context<'_>,
		buf: &mut [u8],
	) -> Poll<std::io::Result<usize>> {
		self.project().rx.poll_read(cx, buf)
	}
}
impl AsyncBufRead for MuxStreamAsyncRead {
	fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<&[u8]>> {
		self.project().rx.poll_fill_buf(cx)
	}
	fn consume(self: Pin<&mut Self>, amt: usize) {
		self.project().rx.consume(amt)
	}
}

pin_project! {
	/// Write side of a multiplexor stream that implements futures `AsyncWrite`.
	pub struct MuxStreamAsyncWrite {
		#[pin]
		tx: MuxStreamIoSink,
		error: Option<std::io::Error>
	}
}

impl MuxStreamAsyncWrite {
	pub(crate) fn new(sink: MuxStreamIoSink) -> Self {
		Self {
			tx: sink,
			error: None,
		}
	}

	/// Get the stream's close reason, if it was closed.
	pub fn get_close_reason(&self) -> Option<CloseReason> {
		self.tx.get_close_reason()
	}
}

impl AsyncWrite for MuxStreamAsyncWrite {
	fn poll_write(
		mut self: Pin<&mut Self>,
		cx: &mut Context<'_>,
		buf: &[u8],
	) -> Poll<std::io::Result<usize>> {
		if let Some(err) = self.error.take() {
			return Poll::Ready(Err(err));
		}

		let mut this = self.as_mut().project();

		ready!(this.tx.as_mut().poll_ready(cx))?;
		match this.tx.as_mut().start_send(buf) {
			Ok(()) => {
				let mut cx = Context::from_waker(noop_waker_ref());
				let cx = &mut cx;

				match this.tx.poll_flush(cx) {
					Poll::Ready(Err(err)) => {
						self.error = Some(err);
					}
					Poll::Ready(Ok(_)) | Poll::Pending => {}
				}

				Poll::Ready(Ok(buf.len()))
			}
			Err(e) => Poll::Ready(Err(e)),
		}
	}

	fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
		self.project().tx.poll_flush(cx)
	}

	fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
		self.project().tx.poll_close(cx)
	}
}