package notify

import (
	"context"
	"errors"
	"time"
)

type StreamOpenRequest struct {
	StreamID     string
	DataID       uint64
	Channel      StreamChannel
	Metadata     StreamMetadata
	ReadTimeout  time.Duration
	WriteTimeout time.Duration
}

type StreamOpenResponse struct {
	StreamID            string
	DataID              uint64
	Accepted            bool
	TransportGeneration uint64
	Error               string
}

type StreamCloseRequest struct {
	StreamID string
	Full     bool
}

type StreamCloseResponse struct {
	StreamID string
	Accepted bool
	Error    string
}

type StreamResetRequest struct {
	StreamID string
	DataID   uint64
	Error    string
}

type StreamResetResponse struct {
	StreamID string
	Accepted bool
	Error    string
}

func bindClientStreamControl(c *ClientCommon) {
	if c == nil {
		return
	}
	c.SetLink(StreamOpenSignalKey, func(msg *Message) {
		c.handleInboundStreamOpen(msg)
	})
	c.SetLink(StreamCloseSignalKey, func(msg *Message) {
		c.handleInboundStreamClose(msg)
	})
	c.SetLink(StreamResetSignalKey, func(msg *Message) {
		c.handleInboundStreamReset(msg)
	})
}

func bindServerStreamControl(s *ServerCommon) {
	if s == nil {
		return
	}
	s.SetLink(StreamOpenSignalKey, func(msg *Message) {
		s.handleInboundStreamOpen(msg)
	})
	s.SetLink(StreamCloseSignalKey, func(msg *Message) {
		s.handleInboundStreamClose(msg)
	})
	s.SetLink(StreamResetSignalKey, func(msg *Message) {
		s.handleInboundStreamReset(msg)
	})
}

func (c *ClientCommon) handleInboundStreamOpen(msg *Message) {
	req, err := decodeStreamOpenRequest(msg)
	resp := StreamOpenResponse{StreamID: req.StreamID, DataID: req.DataID}
	if err != nil {
		resp.Error = err.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	runtime := c.getStreamRuntime()
	if runtime == nil {
		resp.Error = errStreamRuntimeNil.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	scope := clientFileScope()
	if req.DataID == 0 {
		req.DataID = runtime.nextDataID()
		resp.DataID = req.DataID
	}
	stream := newStreamHandle(c.clientStopContextSnapshot(), runtime, scope, req, c.currentClientSessionEpoch(), nil, nil, 0, clientStreamCloseSender(c), clientStreamResetSender(c), clientStreamDataSender(c, c.currentClientSessionEpoch()), runtime.configSnapshot())
	stream.setClientSnapshotOwner(c)
	stream.setAddrSnapshot(c.clientStreamAddrSnapshot())
	if err := runtime.register(scope, stream); err != nil {
		resp.Error = err.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	if claimed, err := c.claimInboundRecordStream(stream); claimed {
		if err != nil {
			stream.markReset(err)
			resp.Error = err.Error()
			replyStreamControlIfNeeded(msg, resp)
			return
		}
		resp.Accepted = true
		resp.TransportGeneration = stream.TransportGeneration()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	if claimed, err := c.claimInboundTransferStream(stream); claimed {
		if err != nil {
			stream.markReset(err)
			resp.Error = err.Error()
			replyStreamControlIfNeeded(msg, resp)
			return
		}
		resp.Accepted = true
		resp.TransportGeneration = stream.TransportGeneration()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	handler := runtime.handlerSnapshot()
	if handler == nil {
		stream.markReset(errStreamHandlerNotConfigured)
		resp.Error = errStreamHandlerNotConfigured.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	info := StreamAcceptInfo{
		ID:                  stream.ID(),
		DataID:              stream.dataIDSnapshot(),
		Channel:             stream.Channel(),
		Metadata:            stream.Metadata(),
		TransportGeneration: stream.TransportGeneration(),
		Stream:              stream,
	}
	if err := handler(info); err != nil {
		stream.markReset(err)
		resp.Error = err.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	resp.Accepted = true
	resp.DataID = stream.dataIDSnapshot()
	resp.TransportGeneration = stream.TransportGeneration()
	replyStreamControlIfNeeded(msg, resp)
}

func (s *ServerCommon) handleInboundStreamOpen(msg *Message) {
	req, err := decodeStreamOpenRequest(msg)
	resp := StreamOpenResponse{StreamID: req.StreamID, DataID: req.DataID}
	if err != nil {
		resp.Error = err.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	runtime := s.getStreamRuntime()
	if runtime == nil {
		resp.Error = errStreamRuntimeNil.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	logical := messageLogicalConnSnapshot(msg)
	if logical == nil {
		resp.Error = errStreamLogicalConnNil.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	transport := messageTransportConnSnapshot(msg)
	scope := serverFileScope(logical)
	if req.DataID == 0 {
		req.DataID = runtime.nextDataID()
		resp.DataID = req.DataID
	}
	stream := newStreamHandle(logical.stopContextSnapshot(), runtime, scope, req, 0, logical, transport, streamTransportGeneration(logical, transport), serverStreamCloseSender(s, logical, transport), serverStreamResetSender(s, logical, transport), serverStreamDataSender(s, transport), runtime.configSnapshot())
	if err := runtime.register(scope, stream); err != nil {
		resp.Error = err.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	if claimed, err := s.claimInboundRecordStream(logical, transport, stream); claimed {
		if err != nil {
			stream.markReset(err)
			resp.Error = err.Error()
			replyStreamControlIfNeeded(msg, resp)
			return
		}
		resp.Accepted = true
		resp.TransportGeneration = stream.TransportGeneration()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	if claimed, err := s.claimInboundTransferStream(logical, transport, stream); claimed {
		if err != nil {
			stream.markReset(err)
			resp.Error = err.Error()
			replyStreamControlIfNeeded(msg, resp)
			return
		}
		resp.Accepted = true
		resp.TransportGeneration = stream.TransportGeneration()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	handler := runtime.handlerSnapshot()
	if handler == nil {
		stream.markReset(errStreamHandlerNotConfigured)
		resp.Error = errStreamHandlerNotConfigured.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	info := StreamAcceptInfo{
		ID:                  stream.ID(),
		DataID:              stream.dataIDSnapshot(),
		Channel:             stream.Channel(),
		Metadata:            stream.Metadata(),
		LogicalConn:         logical,
		TransportConn:       transport,
		TransportGeneration: stream.TransportGeneration(),
		Stream:              stream,
	}
	if err := handler(info); err != nil {
		stream.markReset(err)
		resp.Error = err.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	resp.Accepted = true
	resp.DataID = stream.dataIDSnapshot()
	resp.TransportGeneration = stream.TransportGeneration()
	replyStreamControlIfNeeded(msg, resp)
}

func (c *ClientCommon) handleInboundStreamClose(msg *Message) {
	req, err := decodeStreamCloseRequest(msg)
	resp := StreamCloseResponse{StreamID: req.StreamID}
	if err != nil {
		resp.Error = err.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	runtime := c.getStreamRuntime()
	if runtime == nil {
		resp.Error = errStreamRuntimeNil.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	stream, ok := runtime.lookup(clientFileScope(), req.StreamID)
	if !ok {
		resp.Error = errStreamNotFound.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	if req.Full {
		stream.markPeerClosed()
	} else {
		stream.markRemoteClosed()
	}
	resp.Accepted = true
	replyStreamControlIfNeeded(msg, resp)
}

func (s *ServerCommon) handleInboundStreamClose(msg *Message) {
	req, err := decodeStreamCloseRequest(msg)
	resp := StreamCloseResponse{StreamID: req.StreamID}
	if err != nil {
		resp.Error = err.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	runtime := s.getStreamRuntime()
	if runtime == nil {
		resp.Error = errStreamRuntimeNil.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	logical := messageLogicalConnSnapshot(msg)
	scope := serverFileScope(logical)
	stream, ok := runtime.lookup(scope, req.StreamID)
	if !ok {
		resp.Error = errStreamNotFound.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	if req.Full {
		stream.markPeerClosed()
	} else {
		stream.markRemoteClosed()
	}
	resp.Accepted = true
	replyStreamControlIfNeeded(msg, resp)
}

func (c *ClientCommon) handleInboundStreamReset(msg *Message) {
	req, err := decodeStreamResetRequest(msg)
	resp := StreamResetResponse{StreamID: req.StreamID}
	if err != nil {
		resp.Error = err.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	runtime := c.getStreamRuntime()
	if runtime == nil {
		resp.Error = errStreamRuntimeNil.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	stream, ok := runtime.lookup(clientFileScope(), req.StreamID)
	if !ok && req.DataID != 0 {
		stream, ok = runtime.lookupByDataID(clientFileScope(), req.DataID)
	}
	if !ok {
		resp.Error = errStreamNotFound.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	if resp.StreamID == "" {
		resp.StreamID = stream.ID()
	}
	stream.markReset(streamResetError(streamRemoteResetError(req.Error)))
	resp.Accepted = true
	replyStreamControlIfNeeded(msg, resp)
}

func (s *ServerCommon) handleInboundStreamReset(msg *Message) {
	req, err := decodeStreamResetRequest(msg)
	resp := StreamResetResponse{StreamID: req.StreamID}
	if err != nil {
		resp.Error = err.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	runtime := s.getStreamRuntime()
	if runtime == nil {
		resp.Error = errStreamRuntimeNil.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	logical := messageLogicalConnSnapshot(msg)
	scope := serverFileScope(logical)
	stream, ok := runtime.lookup(scope, req.StreamID)
	if !ok && req.DataID != 0 {
		stream, ok = runtime.lookupByDataID(scope, req.DataID)
	}
	if !ok {
		resp.Error = errStreamNotFound.Error()
		replyStreamControlIfNeeded(msg, resp)
		return
	}
	if resp.StreamID == "" {
		resp.StreamID = stream.ID()
	}
	stream.markReset(streamResetError(streamRemoteResetError(req.Error)))
	resp.Accepted = true
	replyStreamControlIfNeeded(msg, resp)
}

func replyStreamControlIfNeeded(msg *Message, value interface{}) {
	if msg == nil || !requiresSignalReplyWait(msg.TransferMsg) {
		return
	}
	_ = msg.ReplyObj(value)
}

func sendStreamOpenClient(ctx context.Context, c Client, req StreamOpenRequest) (StreamOpenResponse, error) {
	if c == nil {
		return StreamOpenResponse{}, errStreamClientNil
	}
	msg, err := c.SendObjCtx(ctx, StreamOpenSignalKey, req)
	if err != nil {
		return StreamOpenResponse{}, err
	}
	return decodeStreamOpenResponse(msg)
}

func sendStreamOpenServerLogical(ctx context.Context, s Server, logical *LogicalConn, req StreamOpenRequest) (StreamOpenResponse, error) {
	if s == nil {
		return StreamOpenResponse{}, errStreamServerNil
	}
	if logical == nil {
		return StreamOpenResponse{}, errStreamLogicalConnNil
	}
	msg, err := s.SendObjCtxLogical(ctx, logical, StreamOpenSignalKey, req)
	if err != nil {
		return StreamOpenResponse{}, err
	}
	return decodeStreamOpenResponse(msg)
}

func sendStreamOpenServerTransport(ctx context.Context, s Server, transport *TransportConn, req StreamOpenRequest) (StreamOpenResponse, error) {
	if s == nil {
		return StreamOpenResponse{}, errStreamServerNil
	}
	if transport == nil {
		return StreamOpenResponse{}, errStreamTransportNil
	}
	msg, err := s.SendObjCtxTransport(ctx, transport, StreamOpenSignalKey, req)
	if err != nil {
		return StreamOpenResponse{}, err
	}
	return decodeStreamOpenResponse(msg)
}

func sendStreamCloseClient(ctx context.Context, c Client, req StreamCloseRequest) (StreamCloseResponse, error) {
	if c == nil {
		return StreamCloseResponse{}, errStreamClientNil
	}
	msg, err := c.SendObjCtx(ctx, StreamCloseSignalKey, req)
	if err != nil {
		return StreamCloseResponse{}, err
	}
	return decodeStreamCloseResponse(msg)
}

func sendStreamCloseServerLogical(ctx context.Context, s Server, logical *LogicalConn, req StreamCloseRequest) (StreamCloseResponse, error) {
	if s == nil {
		return StreamCloseResponse{}, errStreamServerNil
	}
	if logical == nil {
		return StreamCloseResponse{}, errStreamLogicalConnNil
	}
	msg, err := s.SendObjCtxLogical(ctx, logical, StreamCloseSignalKey, req)
	if err != nil {
		return StreamCloseResponse{}, err
	}
	return decodeStreamCloseResponse(msg)
}

func sendStreamCloseServerTransport(ctx context.Context, s Server, transport *TransportConn, req StreamCloseRequest) (StreamCloseResponse, error) {
	if s == nil {
		return StreamCloseResponse{}, errStreamServerNil
	}
	if transport == nil {
		return StreamCloseResponse{}, errStreamTransportNil
	}
	msg, err := s.SendObjCtxTransport(ctx, transport, StreamCloseSignalKey, req)
	if err != nil {
		return StreamCloseResponse{}, err
	}
	return decodeStreamCloseResponse(msg)
}

func sendStreamResetClient(ctx context.Context, c Client, req StreamResetRequest) (StreamResetResponse, error) {
	if c == nil {
		return StreamResetResponse{}, errStreamClientNil
	}
	msg, err := c.SendObjCtx(ctx, StreamResetSignalKey, req)
	if err != nil {
		return StreamResetResponse{}, err
	}
	return decodeStreamResetResponse(msg)
}

func sendStreamResetServerLogical(ctx context.Context, s Server, logical *LogicalConn, req StreamResetRequest) (StreamResetResponse, error) {
	if s == nil {
		return StreamResetResponse{}, errStreamServerNil
	}
	if logical == nil {
		return StreamResetResponse{}, errStreamLogicalConnNil
	}
	msg, err := s.SendObjCtxLogical(ctx, logical, StreamResetSignalKey, req)
	if err != nil {
		return StreamResetResponse{}, err
	}
	return decodeStreamResetResponse(msg)
}

func sendStreamResetServerTransport(ctx context.Context, s Server, transport *TransportConn, req StreamResetRequest) (StreamResetResponse, error) {
	if s == nil {
		return StreamResetResponse{}, errStreamServerNil
	}
	if transport == nil {
		return StreamResetResponse{}, errStreamTransportNil
	}
	msg, err := s.SendObjCtxTransport(ctx, transport, StreamResetSignalKey, req)
	if err != nil {
		return StreamResetResponse{}, err
	}
	return decodeStreamResetResponse(msg)
}

func decodeStreamOpenRequest(msg *Message) (StreamOpenRequest, error) {
	var req StreamOpenRequest
	if msg == nil {
		return StreamOpenRequest{}, errStreamIDEmpty
	}
	if err := msg.Value.Orm(&req); err != nil {
		return StreamOpenRequest{}, err
	}
	req = normalizeStreamOpenRequest(req)
	if req.StreamID == "" {
		return StreamOpenRequest{}, errStreamIDEmpty
	}
	return req, nil
}

func decodeStreamCloseRequest(msg *Message) (StreamCloseRequest, error) {
	var req StreamCloseRequest
	if msg == nil {
		return StreamCloseRequest{}, errStreamIDEmpty
	}
	if err := msg.Value.Orm(&req); err != nil {
		return StreamCloseRequest{}, err
	}
	if req.StreamID == "" {
		return StreamCloseRequest{}, errStreamIDEmpty
	}
	return req, nil
}

func decodeStreamResetRequest(msg *Message) (StreamResetRequest, error) {
	var req StreamResetRequest
	if msg == nil {
		return StreamResetRequest{}, errStreamIDEmpty
	}
	if err := msg.Value.Orm(&req); err != nil {
		return StreamResetRequest{}, err
	}
	if req.StreamID == "" {
		return StreamResetRequest{}, errStreamIDEmpty
	}
	return req, nil
}

func decodeStreamOpenResponse(msg Message) (StreamOpenResponse, error) {
	var resp StreamOpenResponse
	if err := msg.Value.Orm(&resp); err != nil {
		return StreamOpenResponse{}, err
	}
	return resp, streamControlResultError("open", resp.Accepted, resp.Error, nil)
}

func decodeStreamCloseResponse(msg Message) (StreamCloseResponse, error) {
	var resp StreamCloseResponse
	if err := msg.Value.Orm(&resp); err != nil {
		return StreamCloseResponse{}, err
	}
	return resp, streamControlResultError("close", resp.Accepted, resp.Error, nil)
}

func decodeStreamResetResponse(msg Message) (StreamResetResponse, error) {
	var resp StreamResetResponse
	if err := msg.Value.Orm(&resp); err != nil {
		return StreamResetResponse{}, err
	}
	return resp, streamControlResultError("reset", resp.Accepted, resp.Error, nil)
}

func streamControlResultError(op string, accepted bool, message string, callErr error) error {
	if callErr != nil {
		return callErr
	}
	if message != "" {
		return streamControlMessageError(message)
	}
	if accepted {
		return nil
	}
	if op == "open" {
		return errStreamRejected
	}
	return errors.New("stream " + op + " rejected")
}

func streamControlMessageError(message string) error {
	switch message {
	case errStreamNotFound.Error():
		return errStreamNotFound
	case errStreamAlreadyExists.Error():
		return errStreamAlreadyExists
	case errStreamHandlerNotConfigured.Error():
		return errStreamHandlerNotConfigured
	case errStreamLogicalConnNil.Error():
		return errStreamLogicalConnNil
	case errStreamTransportNil.Error():
		return errStreamTransportNil
	case errStreamRuntimeNil.Error():
		return errStreamRuntimeNil
	case errStreamIDEmpty.Error():
		return errStreamIDEmpty
	default:
		return errors.New(message)
	}
}

func streamTransportGeneration(logical *LogicalConn, transport *TransportConn) uint64 {
	if transport != nil {
		return transport.TransportGeneration()
	}
	if logical != nil {
		return logical.transportGenerationSnapshot()
	}
	return 0
}

func streamRemoteResetError(message string) error {
	if message == "" {
		return errStreamReset
	}
	return errors.New(message)
}