package handler

import (
	"net/http"
	"strconv"
	"strings"

	"github.com/gin-gonic/gin"
	"kefu-cloud/server/internal/middleware"
	"kefu-cloud/server/internal/service"
	"kefu-cloud/server/internal/ws"
)

type WidgetHandler struct{}

func NewWidgetHandler() *WidgetHandler { return &WidgetHandler{} }

type WidgetInitReq struct {
	ChannelKey  string `json:"channel_key" form:"channel_key"`
	VisitorName string `json:"visitor_name"`
	// DeviceID 访客端持久设备指纹（localStorage），用于设备级拉黑
	DeviceID string `json:"device_id" form:"device_id"`
	// 宿主页信息（由 widget.js / 前端上报）
	PageURL   string `json:"page_url" form:"page_url"`
	PageTitle string `json:"page_title" form:"page_title"`
	Referrer  string `json:"referrer" form:"referrer"`
}

type WidgetPageViewReq struct {
	SessionID    uint   `json:"session_id" binding:"required"`
	VisitorToken string `json:"visitor_token"`
	PageURL      string `json:"page_url" binding:"required"`
	PageTitle    string `json:"page_title"`
}

type WidgetHeartbeatReq struct {
	SessionID    uint   `json:"session_id" binding:"required"`
	VisitorToken string `json:"visitor_token"`
}

type WidgetMessageReq struct {
	SessionID    uint   `json:"session_id" binding:"required"`
	Content      string `json:"content" binding:"required"`
	Type         string `json:"type"`
	VisitorToken string `json:"visitor_token"`
}

type WidgetRatingReq struct {
	SessionID    uint   `json:"session_id" binding:"required"`
	Score        int    `json:"score" binding:"required"`
	Text         string `json:"text"`
	VisitorToken string `json:"visitor_token"`
}

type WidgetLeaveReq struct {
	SessionID    uint   `json:"session_id" binding:"required"`
	Content      string `json:"content" binding:"required"`
	Name         string `json:"name"`
	Phone        string `json:"phone"`
	Email        string `json:"email"`
	VisitorToken string `json:"visitor_token"`
}

func (h *WidgetHandler) Init(c *gin.Context) {
	var req WidgetInitReq
	if err := c.ShouldBindQuery(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "参数错误"})
		return
	}
	if c.Request.Method == http.MethodPost && strings.HasPrefix(c.GetHeader("Content-Type"), "application/json") {
		if err := c.ShouldBindJSON(&req); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "参数错误"})
			return
		}
	}
	if req.ChannelKey == "" {
		req.ChannelKey = c.Query("channel_key")
	}

	// 宿主页信息：body 优先，query 兜底
	pageURL := service.SanitizePageURL(req.PageURL)
	if pageURL == "" {
		pageURL = service.SanitizePageURL(c.Query("page_url"))
	}
	pageTitle := service.SanitizePageTitle(req.PageTitle)
	if pageTitle == "" {
		pageTitle = service.SanitizePageTitle(c.Query("page_title"))
	}
	referrer := service.SanitizePageURL(req.Referrer)
	if referrer == "" {
		referrer = service.SanitizePageURL(c.Query("referrer"))
	}

	ip, region, userAgent, _ := captureVisitorMeta(c)
	resp, err := service.WidgetInit(service.WidgetInitInput{
		ChannelKey:  req.ChannelKey,
		VisitorName: req.VisitorName,
		DeviceID:    req.DeviceID,
		PageURL:     pageURL,
		PageTitle:   pageTitle,
		Referrer:    referrer,
		Meta: service.VisitorMeta{
			IP:        ip,
			Region:    region,
			UserAgent: userAgent,
		},
	})
	if err != nil {
		respondServiceError(c, err)
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "data": resp})
}

// PageView POST /api/widget/pageview — 访客换页上报
func (h *WidgetHandler) PageView(c *gin.Context) {
	var req WidgetPageViewReq
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "参数错误"})
		return
	}
	session, err := service.WidgetSession(req.SessionID, visitorTokenFromRequest(c, req.VisitorToken))
	if err != nil {
		respondServiceError(c, err)
		return
	}
	data, err := service.WidgetPageView(session, service.SanitizePageURL(req.PageURL), service.SanitizePageTitle(req.PageTitle))
	if err != nil {
		respondServiceError(c, err)
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "data": data})
}

// Heartbeat POST /api/widget/heartbeat — 刷新 last_seen，供在线读秒
func (h *WidgetHandler) Heartbeat(c *gin.Context) {
	var req WidgetHeartbeatReq
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "参数错误"})
		return
	}
	session, err := service.WidgetSession(req.SessionID, visitorTokenFromRequest(c, req.VisitorToken))
	if err != nil {
		respondServiceError(c, err)
		return
	}
	ended, lastSeen, err := service.WidgetHeartbeat(session)
	if err != nil {
		respondServiceError(c, err)
		return
	}
	if ended {
		c.JSON(http.StatusOK, gin.H{"code": 0, "data": gin.H{"ok": true, "ended": true}})
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "data": gin.H{"ok": true, "last_seen_at": lastSeen}})
}

func visitorTokenFromRequest(c *gin.Context, bodyToken string) string {
	if token := c.GetHeader("X-Visitor-Token"); token != "" {
		return token
	}
	return bodyToken
}

func (h *WidgetHandler) SendMessage(c *gin.Context) {
	var req WidgetMessageReq
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "参数错误"})
		return
	}
	if req.Type == "" {
		req.Type = "text"
	}
	// 先校验内容，再加载会话（与原校验顺序一致）
	content, err := service.ValidateMessageContent(req.Type, req.Content)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
		return
	}
	session, err := service.WidgetSession(req.SessionID, visitorTokenFromRequest(c, req.VisitorToken))
	if err != nil {
		respondServiceError(c, err)
		return
	}
	msg, err := service.WidgetSendMessage(session, req.Type, content)
	if err != nil {
		respondServiceError(c, err)
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "data": msg})
}

// LeaveMessage 无客服在线时提交留言并沉淀联系方式。
func (h *WidgetHandler) LeaveMessage(c *gin.Context) {
	var req WidgetLeaveReq
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "参数错误"})
		return
	}
	content, err := service.ValidateMessageContent("text", req.Content)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
		return
	}
	name := strings.TrimSpace(req.Name)
	phone := strings.TrimSpace(req.Phone)
	email := strings.TrimSpace(req.Email)
	if err := service.ValidateLeaveContact(name, phone, email); err != nil {
		respondServiceError(c, err)
		return
	}

	session, err := service.WidgetSession(req.SessionID, visitorTokenFromRequest(c, req.VisitorToken))
	if err != nil {
		respondServiceError(c, err)
		return
	}
	result, err := service.WidgetLeaveMessage(session, content, name, phone, email)
	if err != nil {
		respondServiceError(c, err)
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"code": 0,
		"data": gin.H{
			"message":        result.Message,
			"session_status": result.SessionStatus,
			"agents_online":  result.AgentsOnline,
		},
	})
}

func visitorTokenFromWebSocket(c *gin.Context) string {
	protocols := strings.Split(c.GetHeader("Sec-WebSocket-Protocol"), ",")
	if len(protocols) == 2 && strings.TrimSpace(protocols[0]) == "kefu-visitor-v1" {
		return strings.TrimSpace(protocols[1])
	}
	return ""
}

func (h *WidgetHandler) Connect(c *gin.Context) {
	sessionID, err := strconv.ParseUint(c.Query("session_id"), 10, 64)
	if err != nil || sessionID == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "会话参数错误"})
		return
	}
	session, err := service.WidgetSession(uint(sessionID), visitorTokenFromWebSocket(c))
	if err != nil {
		respondServiceError(c, err)
		return
	}
	client, err := ws.UpgradeVisitor(c.Writer, c.Request, session.TenantID, session.ID)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 500, "message": "升级连接失败"})
		return
	}
	ws.HandleWebSocket(client)
}

func (h *WidgetHandler) SubmitRating(c *gin.Context) {
	var req WidgetRatingReq
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "参数错误"})
		return
	}
	if req.Score < 1 || req.Score > 5 {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "评分应为 1 至 5 星"})
		return
	}
	session, err := service.WidgetSession(req.SessionID, visitorTokenFromRequest(c, req.VisitorToken))
	if err != nil {
		respondServiceError(c, err)
		return
	}
	if err := service.WidgetSubmitRating(session, req.Score, req.Text); err != nil {
		respondServiceError(c, err)
		return
	}
	middleware.JSON(c, gin.H{"message": "感谢您的评价"})
}

func (h *WidgetHandler) GetMessages(c *gin.Context) {
	sessionID, err := strconv.ParseUint(c.Query("session_id"), 10, 64)
	if err != nil || sessionID == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "会话参数错误"})
		return
	}
	session, err := service.WidgetSession(uint(sessionID), visitorTokenFromRequest(c, ""))
	if err != nil {
		respondServiceError(c, err)
		return
	}

	afterSeq := 0
	if raw := strings.TrimSpace(c.Query("after_seq")); raw != "" {
		parsed, err := strconv.Atoi(raw)
		if err != nil || parsed < 0 {
			c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "after_seq 无效"})
			return
		}
		afterSeq = parsed
	}

	limit := 200
	if raw := strings.TrimSpace(c.Query("limit")); raw != "" {
		if parsed, err := strconv.Atoi(raw); err == nil && parsed > 0 {
			if parsed > 500 {
				parsed = 500
			}
			limit = parsed
		}
	}

	data, err := service.WidgetMessages(session, afterSeq, limit)
	if err != nil {
		respondServiceError(c, err)
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": 0, "data": data})
}