package handler

import (
	"context"
	"io"
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"
	"github.com/livekit/protocol/livekit"
	"go.uber.org/zap"

	"with_you/internal/config"
	"with_you/internal/pkg/response"
	"with_you/internal/service"
)

// LiveKitHandler LiveKit 令牌和 Webhook 处理器
type LiveKitHandler struct {
	liveKitService service.LiveKitService
	callService    service.CallService
	config         *config.LiveKitConfig
	logger         *zap.Logger
}

// NewLiveKitHandler 创建 LiveKit 处理器
func NewLiveKitHandler(
	liveKitService service.LiveKitService,
	callService service.CallService,
	cfg *config.Config,
	logger *zap.Logger,
) *LiveKitHandler {
	return &LiveKitHandler{
		liveKitService: liveKitService,
		callService:    callService,
		config:         &cfg.LiveKit,
		logger:         logger,
	}
}

// GetToken 生成 LiveKit 访问令牌
// GET /api/v1/calls/token?room=<callID>
func (h *LiveKitHandler) GetToken(c *gin.Context) {
	if !h.config.Enabled {
		response.Forbidden(c, "livekit is not enabled")
		return
	}

	userID, exists := c.Get("user_id")
	if !exists {
		response.Unauthorized(c, "unauthorized")
		return
	}

	room := c.Query("room")
	if room == "" {
		response.BadRequest(c, "room parameter is required")
		return
	}

	// 验证用户是该通话的参与者
	activeCall := h.callService.GetActiveCall(c.Request.Context(), room)
	if activeCall == nil {
		response.NotFound(c, "call not found or already ended")
		return
	}

	isParticipant := false
	for _, p := range activeCall.Participants {
		if p.UserID == userID.(string) {
			isParticipant = true
			break
		}
	}
	if !isParticipant && activeCall.CallerID != userID.(string) && activeCall.CalleeID != userID.(string) {
		response.Forbidden(c, "not a participant of this call")
		return
	}

	canPublish := true
	canSubscribe := true
	if cp := c.Query("can_publish"); cp != "" {
		canPublish, _ = strconv.ParseBool(cp)
	}
	if cs := c.Query("can_subscribe"); cs != "" {
		canSubscribe, _ = strconv.ParseBool(cs)
	}

	token, err := h.liveKitService.GenerateToken(room, userID.(string), canPublish, canSubscribe)
	if err != nil {
		h.logger.Error("failed to generate livekit token", zap.Error(err))
		response.InternalServerError(c, "failed to generate token")
		return
	}

	response.Success(c, gin.H{
		"token": token,
		"url":   h.config.URL,
	})
}

// HandleWebhook 处理 LiveKit Webhook 回调
// POST /api/v1/calls/webhook
func (h *LiveKitHandler) HandleWebhook(c *gin.Context) {
	if !h.config.Enabled {
		c.JSON(http.StatusNotFound, gin.H{"error": "livekit is not enabled"})
		return
	}

	body, err := io.ReadAll(c.Request.Body)
	if err != nil {
		h.logger.Error("failed to read webhook body", zap.Error(err))
		c.JSON(http.StatusBadRequest, gin.H{"error": "failed to read body"})
		return
	}

	authHeader := c.GetHeader("Authorization")
	event, err := h.liveKitService.ProcessWebhook(c.Request.Context(), body, authHeader)
	if err != nil {
		h.logger.Error("failed to process webhook", zap.Error(err))
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid webhook"})
		return
	}

	// 根据 webhook 事件类型处理
	switch event.Event {
	case "room_finished":
		h.handleRoomFinished(c.Request.Context(), event)
	case "participant_left":
		identity := event.Participant.GetIdentity()
		roomName := event.Room.GetName()
		h.logger.Info("participant left room",
			zap.String("room", roomName),
			zap.String("identity", identity),
		)
		if identity != "" && roomName != "" {
			if err := h.callService.ParticipantLeave(c.Request.Context(), roomName, identity, "left_livekit"); err != nil {
				h.logger.Warn("failed to handle participant_left",
					zap.String("room", roomName),
					zap.String("identity", identity),
					zap.Error(err),
				)
			}
		}
	}

	c.JSON(http.StatusOK, gin.H{"status": "ok"})
}

// handleRoomFinished 处理 room_finished 事件，作为通话历史持久化的安全兜底
func (h *LiveKitHandler) handleRoomFinished(ctx context.Context, event *livekit.WebhookEvent) {
	roomName := event.Room.GetName()
	if roomName == "" {
		return
	}

	// 尝试结束通话（如果尚未结束）
	// callService.End 会检查调用是否仍然活跃，如果已经结束则返回 nil
	_, err := h.callService.End(ctx, roomName, "", "room_finished")
	if err != nil {
		h.logger.Debug("room_finished: call end returned error (may already be ended)",
			zap.String("room", roomName),
			zap.Error(err),
		)
	}
}