package notify

import (
	"context"
	"net"
)

func (c *ClientCommon) SetStreamHandler(fn func(StreamAcceptInfo) error) {
	runtime := c.getStreamRuntime()
	if runtime == nil {
		return
	}
	runtime.setHandler(fn)
}

func (c *ClientCommon) OpenStream(ctx context.Context, opt StreamOpenOptions) (Stream, error) {
	if c == nil {
		return nil, errStreamClientNil
	}
	runtime := c.getStreamRuntime()
	if runtime == nil {
		return nil, errStreamRuntimeNil
	}
	route := c.clientSessionRouteSnapshot()
	if err := c.ensureClientSessionRouteSendReady(route); err != nil {
		return nil, err
	}
	scope := clientFileScope()
	req := clientStreamRequest(runtime, opt)
	if req.StreamID == "" {
		return nil, errStreamIDEmpty
	}
	if existing, exists := runtime.lookup(scope, req.StreamID); exists {
		if existing.acceptsClientSessionRoute(route) {
			return nil, errStreamAlreadyExists
		}
		existing.markReset(transportDetachedSessionEpochError())
	}
	dataID, err := runtime.reserveDataID(scope)
	if err != nil {
		return nil, err
	}
	req.DataID = dataID
	parent := clientSessionRouteContext(route)
	if parent == nil {
		parent = c.clientStopContextSnapshot()
	}
	stream := newStreamHandle(parent, runtime, scope, req, route.epoch, nil, nil, 0, clientStreamCloseSender(c), clientStreamResetSender(c), clientStreamDataSender(c, route), runtime.configSnapshot())
	stream.setClientSnapshotOwner(c)
	stream.setClientSessionRoute(route)
	stream.setAddrSnapshot(c.clientStreamAddrSnapshotAtRoute(route))
	if err := runtime.adoptReserved(scope, stream); err != nil {
		runtime.releaseDataID(scope, req.DataID)
		return nil, err
	}
	resp, err := sendStreamOpenClientAtRoute(ctx, c, route, req)
	if err != nil {
		c.bestEffortStreamResetAtRoute(route, StreamResetRequest{StreamID: req.StreamID, DataID: req.DataID, Error: err.Error()})
		stream.markReset(err)
		return nil, err
	}
	if resp.DataID != 0 && resp.DataID != req.DataID {
		err = errStreamAlreadyExists
		c.bestEffortStreamResetAtRoute(route, StreamResetRequest{StreamID: req.StreamID, Error: "stream data id mismatch"})
		stream.markReset(err)
		return nil, err
	}
	if resp.FastPathVersion != 0 {
		stream.setFastPathVersion(resp.FastPathVersion)
	} else {
		stream.setFastPathVersion(streamFastPathVersionV1)
	}
	stream.metadata = mergeStreamMetadata(req.Metadata, resp.Metadata)
	stream.setTransportGeneration(resp.TransportGeneration)
	return stream, nil
}

func (c *ClientCommon) clientStreamAddrSnapshot() (net.Addr, net.Addr) {
	return c.clientStreamAddrSnapshotAtRoute(c.clientSessionRouteSnapshot())
}

func (c *ClientCommon) clientStreamAddrSnapshotAtRoute(route clientSessionRoute) (net.Addr, net.Addr) {
	if c == nil {
		return nil, nil
	}
	var conn net.Conn
	if route.binding != nil {
		conn = route.binding.connSnapshot()
	}
	if conn == nil {
		return nil, nil
	}
	return conn.LocalAddr(), conn.RemoteAddr()
}

func clientStreamRequest(runtime *streamRuntime, opt StreamOpenOptions) StreamOpenRequest {
	id := opt.ID
	if id == "" && runtime != nil {
		id = runtime.nextID()
	}
	return normalizeStreamOpenRequest(StreamOpenRequest{
		StreamID:        id,
		FastPathVersion: streamFastPathVersionCurrent,
		Channel:         opt.Channel,
		Metadata:        cloneStreamMetadata(opt.Metadata),
		ReadTimeout:     opt.ReadTimeout,
		WriteTimeout:    opt.WriteTimeout,
	})
}

func clientStreamCloseSender(c *ClientCommon) streamCloseSender {
	return func(ctx context.Context, stream *streamHandle, full bool) error {
		_, err := sendStreamCloseClientAtRoute(ctx, c, stream.clientSessionRouteSnapshot(), StreamCloseRequest{
			StreamID: stream.ID(),
			DataID:   stream.dataIDSnapshot(),
			Full:     full,
		})
		return err
	}
}

func clientStreamResetSender(c *ClientCommon) streamResetSender {
	return func(ctx context.Context, stream *streamHandle, message string) error {
		_, err := sendStreamResetClientAtRoute(ctx, c, stream.clientSessionRouteSnapshot(), StreamResetRequest{
			StreamID:      stream.ID(),
			DataID:        stream.dataIDSnapshot(),
			Error:         message,
			RecordFailure: stream.recordResetFailure(),
		})
		return err
	}
}

func clientStreamDataSender(c *ClientCommon, route clientSessionRoute) streamDataSender {
	return func(ctx context.Context, stream *streamHandle, chunk []byte) error {
		if c == nil {
			return errStreamClientNil
		}
		if err := c.ensureClientSessionRouteSendReady(route); err != nil {
			return err
		}
		if ctx != nil {
			select {
			case <-ctx.Done():
				return ctx.Err()
			default:
			}
		}
		if dataID := stream.dataIDSnapshot(); dataID != 0 {
			return c.sendFastStreamDataAtRoute(ctx, route, stream, chunk)
		}
		return c.sendEnvelopeAtRoute(route, newStreamDataEnvelope(stream.ID(), chunk))
	}
}

func (c *ClientCommon) bestEffortStreamResetAtRoute(route clientSessionRoute, req StreamResetRequest) {
	if c == nil {
		return
	}
	ctx, cancel := context.WithTimeout(context.Background(), streamDispatchRejectTimeout)
	defer cancel()
	_, _ = sendStreamResetClientAtRoute(ctx, c, route, req)
}