package handler

import (
	"errors"
	"net/http"
	"sync"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/wangjia/jiu/backend/internal/middleware"
	"github.com/wangjia/jiu/backend/internal/service"
	"github.com/wangjia/jiu/backend/internal/util"
)

type AuthHandler struct {
	svc    *service.AuthService
	licSvc *service.LicenseService // 用于心跳 /auth/ping 回带授权概况；测试构造可传 nil
}

func NewAuthHandler(svc *service.AuthService, licSvc *service.LicenseService) *AuthHandler {
	return &AuthHandler{svc: svc, licSvc: licSvc}
}

// Login POST /api/v1/auth/login
func (h *AuthHandler) Login(c *gin.Context) {
	var req struct {
		ShopCode   string `json:"shop_code" binding:"required"`
		Username   string `json:"username" binding:"required"`
		Password   string `json:"password" binding:"required"`
		DeviceID   string `json:"device_id"`
		DeviceName string `json:"device_name"`
		Platform   string `json:"platform"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	dev := service.DeviceInfo{
		DeviceID:   req.DeviceID,
		DeviceName: req.DeviceName,
		Platform:   req.Platform,
		IP:         c.ClientIP(),
		UserAgent:  c.Request.UserAgent(),
	}
	pair, user, err := h.svc.Login(req.ShopCode, req.Username, req.Password, dev)
	if err != nil {
		status := http.StatusUnauthorized
		if errors.Is(err, service.ErrTooManyAttempts) {
			status = http.StatusTooManyRequests
		} else if errors.Is(err, service.ErrPlatformNotAllowed) {
			status = http.StatusForbidden
		} else if errors.Is(err, service.ErrDeviceLimitReached) {
			c.JSON(http.StatusConflict, gin.H{"error": err.Error(), "code": "DEVICE_LIMIT"})
			return
		}
		c.JSON(status, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"data": gin.H{
			"access_token":  pair.AccessToken,
			"refresh_token": pair.RefreshToken,
			"expires_in":    pair.ExpiresIn,
			"shop_id":       pair.ShopID,
			"user": gin.H{
				"id":        user.ID,
				"username":  user.Username,
				"real_name": user.RealName,
				"role":      user.Role,
			},
		},
	})
}

// Register POST /api/v1/public/register
func (h *AuthHandler) Register(c *gin.Context) {
	var req service.RegisterInput
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	result, err := h.svc.Register(req)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	util.RespondSuccess(c, result)
}

// Refresh POST /api/v1/auth/refresh
func (h *AuthHandler) Refresh(c *gin.Context) {
	var req struct {
		RefreshToken string `json:"refresh_token" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	pair, err := h.svc.RefreshTokens(req.RefreshToken)
	if err != nil {
		// 被踢/登出/禁用 → 给前端明确 code，便于提示"账号已在其他设备登录/已失效"
		if errors.Is(err, service.ErrSessionRevoked) || errors.Is(err, service.ErrUserInactive) {
			c.JSON(http.StatusUnauthorized, gin.H{"error": err.Error(), "code": "SESSION_REVOKED"})
			return
		}
		c.JSON(http.StatusUnauthorized, gin.H{"error": err.Error()})
		return
	}

	util.RespondSuccess(c, pair)
}

// Logout POST /api/v1/auth/logout —— 撤销当前会话
func (h *AuthHandler) Logout(c *gin.Context) {
	if err := h.svc.Logout(middleware.GetSID(c)); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	util.RespondSuccess(c, gin.H{"ok": true})
}

// Ping POST /api/v1/auth/ping —— 心跳：会话已撤销则中间件直接 401（触发登出），
// 否则刷新 last_seen 并**回带当前授权概况**，使客户端无需再单独轮询 /license/info
// （到期/续费/被改动等变化随心跳即时反映到横幅/只读门禁）。
func (h *AuthHandler) Ping(c *gin.Context) {
	if h.licSvc == nil {
		util.RespondSuccess(c, gin.H{"ok": true})
		return
	}
	view, err := h.licSvc.ShopInfoView(middleware.GetShopID(c))
	if err != nil {
		// 授权查询出错不应让心跳失败（会话本身有效）：省略 license 字段，客户端保留上次状态。
		util.RespondSuccess(c, gin.H{"ok": true})
		return
	}
	// view 可能为 nil（确无授权）→ license:null，与 /license/info 的 data:null 语义一致。
	util.RespondSuccess(c, gin.H{"ok": true, "license": view})
}

// ═══════════════ App → 网页免登录（一次性换票）═══════════════

// webTicketLast 签票限频：每用户 1 秒至多 1 张（票据本就要求已登录，此为防刷兜底）。
var webTicketLast sync.Map // userID → time.Time

// WebTicket POST /api/v1/auth/web-ticket（需登录）：签发一次性网页登录票据。
// App 拿到票后拼 https://<host>/sso?t=<ticket>&redirect=<路径> 打开系统浏览器。
func (h *AuthHandler) WebTicket(c *gin.Context) {
	shopID := middleware.GetShopID(c)
	userID := middleware.GetUserID(c)
	if last, ok := webTicketLast.Load(userID); ok &&
		time.Since(last.(time.Time)) < time.Second {
		c.JSON(http.StatusTooManyRequests, gin.H{"error": "请求过于频繁，请稍后再试"})
		return
	}
	webTicketLast.Store(userID, time.Now())

	ticket, ttl, err := h.svc.IssueWebTicket(shopID, userID)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "签发失败"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"data": gin.H{
		"ticket":     ticket,
		"expires_in": ttl,
	}})
}

// WebTicketExchange POST /api/v1/auth/web-ticket/exchange（公开）：
// 网页端凭一次性票据兑换正常登录态（响应结构同 /auth/login，另带 shop_code
// 供官网 localStorage 回填）。票据单次可用，无效/过期/重放一律 401。
func (h *AuthHandler) WebTicketExchange(c *gin.Context) {
	var req struct {
		Ticket string `json:"ticket" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	dev := service.DeviceInfo{
		Platform:  "web",
		IP:        c.ClientIP(),
		UserAgent: c.Request.UserAgent(),
	}
	pair, user, shop, err := h.svc.LoginWithWebTicket(req.Ticket, dev)
	if err != nil {
		if errors.Is(err, service.ErrTicketInvalid) ||
			errors.Is(err, service.ErrInvalidCredentials) ||
			errors.Is(err, service.ErrUserInactive) {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "票据无效或已过期"})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": "兑换失败"})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"data": gin.H{
			"access_token":  pair.AccessToken,
			"refresh_token": pair.RefreshToken,
			"expires_in":    pair.ExpiresIn,
			"shop_id":       pair.ShopID,
			"shop_code":     shop.Code,
			"user": gin.H{
				"id":        user.ID,
				"username":  user.Username,
				"real_name": user.RealName,
				"role":      user.Role,
			},
		},
	})
}