package hub

import (
	"bytes"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"github.com/gorilla/websocket"
	"websocket-relay/internal/logging"
)

func newTestLogger() *logging.Logger {
	return logging.NewLogger("debug", &bytes.Buffer{})
}

// dialTestHub starts an httptest server for the given hub and dials a
// WebSocket connection to it with the given room query parameter.
// Returns the client-side connection and a cleanup function.
func dialTestHub(t *testing.T, h *Hub, room string) *websocket.Conn {
	t.Helper()
	srv := httptest.NewServer(http.HandlerFunc(h.HandleWebSocket))
	t.Cleanup(srv.Close)

	wsURL := "ws" + strings.TrimPrefix(srv.URL, "http") + "?room=" + room
	conn, _, err := websocket.DefaultDialer.Dial(wsURL, nil)
	if err != nil {
		t.Fatalf("failed to dial WebSocket: %v", err)
	}
	return conn
}

func TestNew(t *testing.T) {
	h := New(newTestLogger())
	if h == nil {
		t.Fatal("New returned nil")
	}
	if h.rooms == nil {
		t.Error("rooms map not initialized")
	}
	if h.connRoom == nil {
		t.Error("connRoom map not initialized")
	}
	if h.broadcast == nil {
		t.Error("broadcast channel not initialized")
	}
	if h.stop == nil {
		t.Error("stop channel not initialized")
	}
}

func TestClientCount(t *testing.T) {
	h := New(newTestLogger())
	go h.Run()
	defer h.Shutdown()

	if count := h.ClientCount(); count != 0 {
		t.Errorf("Expected 0 clients, got %d", count)
	}
}

func TestRoomCount(t *testing.T) {
	h := New(newTestLogger())
	go h.Run()
	defer h.Shutdown()

	if count := h.RoomCount(); count != 0 {
		t.Errorf("Expected 0 rooms, got %d", count)
	}
}

func TestBroadcastChannel(t *testing.T) {
	h := New(newTestLogger())
	go h.Run()
	defer h.Shutdown()

	select {
	case h.broadcast <- broadcastMsg{room: "", data: []byte("test")}:
		// Channel is working
	case <-time.After(100 * time.Millisecond):
		t.Error("broadcast channel blocked")
	}
}

func TestShutdown(t *testing.T) {
	h := New(newTestLogger())

	done := make(chan struct{})
	go func() {
		h.Run()
		close(done)
	}()

	// Ensure Run is processing before shutdown
	time.Sleep(10 * time.Millisecond)

	h.Shutdown()

	select {
	case <-done:
		// Hub.Run() returned successfully
	case <-time.After(1 * time.Second):
		t.Fatal("Hub.Run() did not return after Shutdown")
	}
}

func TestRegisterClient(t *testing.T) {
	h := New(newTestLogger())
	go h.Run()
	defer h.Shutdown()

	conn := dialTestHub(t, h, "test-room")
	defer conn.Close()

	// Allow register to be processed
	time.Sleep(50 * time.Millisecond)

	if count := h.ClientCount(); count != 1 {
		t.Errorf("Expected 1 client, got %d", count)
	}
	if count := h.RoomCount(); count != 1 {
		t.Errorf("Expected 1 room, got %d", count)
	}
}

func TestUnregisterClient(t *testing.T) {
	h := New(newTestLogger())
	go h.Run()
	defer h.Shutdown()

	conn := dialTestHub(t, h, "test-room")

	// Allow register to be processed
	time.Sleep(50 * time.Millisecond)

	if count := h.ClientCount(); count != 1 {
		t.Errorf("Expected 1 client after register, got %d", count)
	}

	// Close the client-side connection to trigger unregister
	conn.Close()

	// Allow unregister to be processed
	time.Sleep(50 * time.Millisecond)

	if count := h.ClientCount(); count != 0 {
		t.Errorf("Expected 0 clients after unregister, got %d", count)
	}
	if count := h.RoomCount(); count != 0 {
		t.Errorf("Expected 0 rooms after last client leaves, got %d", count)
	}
}

func TestRegisterMultipleRooms(t *testing.T) {
	h := New(newTestLogger())
	go h.Run()
	defer h.Shutdown()

	conn1 := dialTestHub(t, h, "room-a")
	defer conn1.Close()
	conn2 := dialTestHub(t, h, "room-a")
	defer conn2.Close()
	conn3 := dialTestHub(t, h, "room-b")
	defer conn3.Close()

	// Allow all registers to be processed
	time.Sleep(50 * time.Millisecond)

	if count := h.ClientCount(); count != 3 {
		t.Errorf("Expected 3 clients, got %d", count)
	}
	if count := h.RoomCount(); count != 2 {
		t.Errorf("Expected 2 rooms, got %d", count)
	}
}

func TestUnregisterCleansUpEmptyRoom(t *testing.T) {
	h := New(newTestLogger())
	go h.Run()
	defer h.Shutdown()

	conn1 := dialTestHub(t, h, "shared-room")
	conn2 := dialTestHub(t, h, "shared-room")

	// Allow registers to be processed
	time.Sleep(50 * time.Millisecond)

	if count := h.RoomCount(); count != 1 {
		t.Errorf("Expected 1 room, got %d", count)
	}

	// Remove first client — room should still exist
	conn1.Close()
	time.Sleep(50 * time.Millisecond)

	if count := h.ClientCount(); count != 1 {
		t.Errorf("Expected 1 client after first disconnect, got %d", count)
	}
	if count := h.RoomCount(); count != 1 {
		t.Errorf("Expected room to still exist with 1 client, got %d rooms", count)
	}

	// Remove second client — room should be cleaned up
	conn2.Close()
	time.Sleep(50 * time.Millisecond)

	if count := h.ClientCount(); count != 0 {
		t.Errorf("Expected 0 clients after both disconnect, got %d", count)
	}
	if count := h.RoomCount(); count != 0 {
		t.Errorf("Expected room to be cleaned up, got %d rooms", count)
	}
}

func TestUnregisterUnknownConnNoPanic(t *testing.T) {
	h := New(newTestLogger())
	go h.Run()
	defer h.Shutdown()

	// Create a raw WebSocket connection that is NOT registered with the hub
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		upgrader := websocket.Upgrader{CheckOrigin: func(r *http.Request) bool { return true }}
		conn, err := upgrader.Upgrade(w, r, nil)
		if err != nil {
			return
		}
		// Send directly to unregister without ever registering
		h.unregister <- conn
	}))
	defer srv.Close()

	wsURL := "ws" + strings.TrimPrefix(srv.URL, "http")
	conn, _, err := websocket.DefaultDialer.Dial(wsURL, nil)
	if err != nil {
		t.Fatalf("failed to dial: %v", err)
	}
	defer conn.Close()

	// Allow unregister to be processed — should not panic
	time.Sleep(50 * time.Millisecond)

	if count := h.ClientCount(); count != 0 {
		t.Errorf("Expected 0 clients, got %d", count)
	}
}

func TestBroadcastRoomIsolation(t *testing.T) {
	h := New(newTestLogger())
	go h.Run()
	defer h.Shutdown()

	connA := dialTestHub(t, h, "room-a")
	defer connA.Close()
	connB := dialTestHub(t, h, "room-b")
	defer connB.Close()

	// Allow registers to be processed
	time.Sleep(50 * time.Millisecond)

	// Send message to room-a via broadcast channel
	h.broadcast <- broadcastMsg{room: "room-a", data: []byte("for-a-only")}

	// Room-a client should receive the message
	connA.SetReadDeadline(time.Now().Add(time.Second))
	_, msg, err := connA.ReadMessage()
	if err != nil {
		t.Fatalf("Room-a client failed to read: %v", err)
	}
	if string(msg) != "for-a-only" {
		t.Errorf("Expected %q, got %q", "for-a-only", string(msg))
	}

	// Room-b client should NOT receive the message (short timeout)
	connB.SetReadDeadline(time.Now().Add(100 * time.Millisecond))
	_, _, err = connB.ReadMessage()
	if err == nil {
		t.Fatal("Room-b client should NOT have received room-a's message")
	}
}