package ws

import (
	"net/http"
	"strings"

	"github.com/edu-cloud/push-gateway/internal/hub"
	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
	"github.com/gorilla/websocket"
)

var upgrader = websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool {
		return true // P5 骨架，生产环境需校验 origin
	},
}

type Handler struct {
	hub       *hub.Hub
	jwtSecret string
}

func NewHandler(h *hub.Hub, jwtSecret string) *Handler {
	return &Handler{hub: h, jwtSecret: jwtSecret}
}

func (h *Handler) HandleWebSocket(c *gin.Context) {
	// 从 query 参数获取 token（WebSocket 无法设置 Authorization 头）
	tokenStr := c.Query("token")
	if tokenStr == "" {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "missing token"})
		return
	}

	token, err := jwt.Parse(tokenStr, func(t *jwt.Token) (interface{}, error) {
		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, jwt.ErrSignatureInvalid
		}
		return []byte(h.jwtSecret), nil
	})

	if err != nil || !token.Valid {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "invalid token"})
		return
	}

	claims, ok := token.Claims.(jwt.MapClaims)
	if !ok {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "invalid claims"})
		return
	}

	userID, ok := claims["sub"].(string)
	if !ok {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "missing user id"})
		return
	}

	conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
	if err != nil {
		return
	}
	defer conn.Close()

	h.hub.Register(userID, conn)
	defer h.hub.Unregister(userID, conn)

	// 读取循环（保持连接，处理心跳）
	for {
		_, msg, err := conn.ReadMessage()
		if err != nil {
			break
		}
		// 处理心跳 ping
		if strings.ToLower(string(msg)) == "ping" {
			conn.WriteMessage(websocket.TextMessage, []byte("pong"))
		}
	}
}

// PushHandler 接收来自 Msg 服务的推送请求
func (h *Handler) PushHandler(c *gin.Context) {
	var req struct {
		UserID  string `json:"user_id"`
		Message string `json:"message"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": gin.H{"code": "INVALID_REQUEST", "message": err.Error()}})
		return
	}

	if err := h.hub.SendToUser(req.UserID, []byte(req.Message)); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": gin.H{"code": "PUSH_FAILED", "message": err.Error()}})
		return
	}

	c.JSON(http.StatusOK, gin.H{"success": true})
}