package fabricproto

import (
	"context"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/gorilla/websocket"
)

func TestRunWebSocketHandlesBinaryFrames(t *testing.T) {
	events := make(chan SessionEventType, 4)
	server := newFabricWebSocketTestServer(t, TransportLoop{
		Session: NewSession(SessionConfig{}),
		OnEvent: func(event SessionEvent) ([]Frame, error) {
			events <- event.Type
			return nil, nil
		},
	})
	defer server.Close()

	conn := dialFabricWebSocket(t, server.URL)
	defer conn.Close()

	writeWebSocketFrame(t, conn, Frame{Type: FrameOpenStream, TrafficClass: TrafficClassInteractive, StreamID: 7})
	writeWebSocketFrame(t, conn, Frame{Type: FrameData, TrafficClass: TrafficClassInteractive, StreamID: 7, Sequence: 9, Payload: []byte("hello")})

	if got := <-events; got != SessionEventStreamOpened {
		t.Fatalf("first event = %s, want stream_opened", got)
	}
	if got := <-events; got != SessionEventData {
		t.Fatalf("second event = %s, want data", got)
	}
	ack := readWebSocketFrame(t, conn)
	if ack.Type != FrameAck || ack.StreamID != 7 || ack.Sequence != 9 {
		t.Fatalf("ack = %+v", ack)
	}
}

func TestRunWebSocketPongAndHandlerResponse(t *testing.T) {
	server := newFabricWebSocketTestServer(t, TransportLoop{
		Session: NewSession(SessionConfig{}),
		OnEvent: func(event SessionEvent) ([]Frame, error) {
			if event.Type != SessionEventPing {
				return nil, nil
			}
			return []Frame{{Type: FrameSessionReady, Payload: []byte("ready")}}, nil
		},
	})
	defer server.Close()

	conn := dialFabricWebSocket(t, server.URL)
	defer conn.Close()

	writeWebSocketFrame(t, conn, Frame{Type: FramePing, Sequence: 4, Payload: []byte("probe")})
	pong := readWebSocketFrame(t, conn)
	if pong.Type != FramePong || pong.Sequence != 4 || string(pong.Payload) != "probe" {
		t.Fatalf("pong = %+v", pong)
	}
	ready := readWebSocketFrame(t, conn)
	if ready.Type != FrameSessionReady || string(ready.Payload) != "ready" {
		t.Fatalf("ready = %+v", ready)
	}
}

func TestRunWebSocketIgnoresTextMessages(t *testing.T) {
	server := newFabricWebSocketTestServer(t, TransportLoop{Session: NewSession(SessionConfig{})})
	defer server.Close()

	conn := dialFabricWebSocket(t, server.URL)
	defer conn.Close()

	if err := conn.WriteMessage(websocket.TextMessage, []byte("ignore me")); err != nil {
		t.Fatalf("write text: %v", err)
	}
	writeWebSocketFrame(t, conn, Frame{Type: FramePing, Sequence: 1})
	pong := readWebSocketFrame(t, conn)
	if pong.Type != FramePong || pong.Sequence != 1 {
		t.Fatalf("pong = %+v", pong)
	}
}

func newFabricWebSocketTestServer(t *testing.T, loop TransportLoop) *httptest.Server {
	t.Helper()
	upgrader := websocket.Upgrader{CheckOrigin: func(*http.Request) bool { return true }}
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		conn, err := upgrader.Upgrade(w, r, nil)
		if err != nil {
			return
		}
		defer conn.Close()
		_ = loop.RunWebSocket(r.Context(), conn, WebSocketTransportConfig{WriteTimeout: time.Second})
	}))
	return server
}

func dialFabricWebSocket(t *testing.T, httpURL string) *websocket.Conn {
	t.Helper()
	wsURL := "ws" + httpURL[len("http"):]
	conn, _, err := websocket.DefaultDialer.Dial(wsURL, nil)
	if err != nil {
		t.Fatalf("dial websocket: %v", err)
	}
	return conn
}

func writeWebSocketFrame(t *testing.T, conn *websocket.Conn, frame Frame) {
	t.Helper()
	encoded, err := MarshalFrame(frame)
	if err != nil {
		t.Fatalf("marshal frame: %v", err)
	}
	if err := conn.WriteMessage(websocket.BinaryMessage, encoded); err != nil {
		t.Fatalf("write websocket frame: %v", err)
	}
}

func readWebSocketFrame(t *testing.T, conn *websocket.Conn) Frame {
	t.Helper()
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()
	type result struct {
		messageType int
		payload     []byte
		err         error
	}
	ch := make(chan result, 1)
	go func() {
		messageType, payload, err := conn.ReadMessage()
		ch <- result{messageType: messageType, payload: payload, err: err}
	}()
	select {
	case <-ctx.Done():
		t.Fatal("timed out waiting for websocket frame")
	case got := <-ch:
		if got.err != nil {
			t.Fatalf("read websocket frame: %v", got.err)
		}
		if got.messageType != websocket.BinaryMessage {
			t.Fatalf("message type = %d, want binary", got.messageType)
		}
		frame, err := UnmarshalFrame(got.payload, DefaultMaxPayload)
		if err != nil {
			t.Fatalf("unmarshal websocket frame: %v", err)
		}
		return frame
	}
	return Frame{}
}