package server

import (
	"embed"
	"html/template"
	"live-streamer/streamer"
	"net/http"
	"os"
	"sync"
	"time"

	"github.com/gin-gonic/gin"
	uuid "github.com/gofrs/uuid/v5"
	"github.com/gorilla/websocket"
	"go.uber.org/zap"
)

//go:embed static
var staticFiles embed.FS

var upgrader = websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool {
		return true
	},
}

type Server struct {
	addr     string
	clients  map[string]*Client
	mu       sync.Mutex
	option   *Option
	log      *zap.Logger
	streamer *streamer.Streamer
}

type Option struct {
	AuthToken string
}

type Client struct {
	id          string
	conn        *websocket.Conn
	mu          sync.Mutex
	hasSentSize int
}

var (
	GlobalServer *Server

	log *zap.Logger
)

func NewServer(addr string, streamer *streamer.Streamer, log *zap.Logger, option *Option) {
	GlobalServer = &Server{
		addr:     addr,
		option:   option,
		clients:  make(map[string]*Client),
		log:      log,
		streamer: streamer,
	}
}

func (s *Server) Run() {
	gin.SetMode(gin.ReleaseMode)
	router := gin.New()
	tpl, err := template.ParseFS(staticFiles, "static/*")
	if err != nil {
		log.Fatal("parsing templates error", zap.Error(err))
	}
	router.SetHTMLTemplate(tpl)

	router.GET("/ws", s.AuthMiddleware(), s.handleWebSocket)
	router.GET(
		"/", func(c *gin.Context) {
			c.HTML(200, "index.html", nil)
		},
	)

	go func() {
		if err := router.Run(s.addr); err != nil {
			log.Fatal("starting server error", zap.Error(err))
		}
	}()
}

func (s *Server) handleWebSocket(c *gin.Context) {
	ws, err := upgrader.Upgrade(c.Writer, c.Request, nil)
	if err != nil {
		return
	}

	ws.SetCloseHandler(func(code int, text string) error {
		return nil
	})

	id, err := uuid.NewV7()
	if err != nil {
		log.Error("generating uuid error", zap.Error(err))
		return
	}
	client := &Client{id: id.String(), conn: ws, hasSentSize: 0}
	s.mu.Lock()
	s.clients[client.id] = client
	s.mu.Unlock()

	defer func() {
		client.mu.Lock()
		ws.Close()
		client.mu.Unlock()
		s.mu.Lock()
		delete(s.clients, client.id)
		s.mu.Unlock()
		if r := recover(); r != nil {
			log.Panic("webSocket handler panic", zap.Any("recover", r))
		}
	}()

	go func() {
		ticker := time.NewTicker(1 * time.Second)
		for range ticker.C {
			s.Broadcast(Data{
				Timestamp:        time.Now().UnixMilli(),
				CurrentVideoPath: s.streamer.GetCurrentVideoPath(),
				VideoList:        s.streamer.GetVideoListPath(),
				Output:           s.streamer.GetOutput(),
			})
		}
	}()

	for {
		// recive message
		client.mu.Lock()
		msg := Request{}
		err := ws.ReadJSON(&msg)
		client.mu.Unlock()
		if err != nil {
			break
		}
		s.RequestHandler(msg.Type)
	}
}

func (s *Server) AuthMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		if s.option.AuthToken == "" ||
			c.Query("token") == s.option.AuthToken {
			c.Next()
		} else {
			c.AbortWithStatus(http.StatusUnauthorized)
		}
	}
}

func (s *Server) Broadcast(obj Data) {
	s.mu.Lock()
	for _, client := range s.clients {
		obj.Timestamp = time.Now().UnixMilli()
		if err := client.conn.WriteJSON(obj); err != nil {
			log.Error("websocket writing message error", zap.Error(err))
		}
	}
	s.mu.Unlock()
}

func (s *Server) Single(userID string, obj Data) {
	s.mu.Lock()
	if client, ok := s.clients[userID]; ok {
		obj.Timestamp = time.Now().UnixMilli()
		if err := client.conn.WriteJSON(obj); err != nil {
			log.Error("websocket writing message error", zap.Error(err))
		}
	}
	s.mu.Unlock()
}

func (s *Server) RequestHandler(reqType RequestType) {
	switch reqType {
	case TypeStreamNextVideo:
		s.streamer.Next()
	case TypeStreamPrevVideo:
		s.streamer.Prev()
	case TypeQuit:
		s.streamer.Close()
		os.Exit(0)
	}
}