package handler

import (
	"dianshang/internal/service"
	"dianshang/pkg/response"
	"dianshang/pkg/utils"

	"github.com/gin-gonic/gin"
)

// CouponHandler 优惠券处理器
type CouponHandler struct {
	couponService *service.CouponService
}

// NewCouponHandler 创建优惠券处理器
func NewCouponHandler(couponService *service.CouponService) *CouponHandler {
	return &CouponHandler{
		couponService: couponService,
	}
}

// GetAvailableCoupons 获取可用优惠券列表
func (h *CouponHandler) GetAvailableCoupons(c *gin.Context) {
	// 尝试获取用户ID，如果有用户登录则返回包含已领取状态的数据
	userIDValue, exists := c.Get("user_id")
	var userID uint = 0
	if exists {
		userID = userIDValue.(uint)
	}

	coupons, err := h.couponService.GetAvailableCouponsWithUserStatus(userID)
	if err != nil {
		response.ErrorWithMessage(c, response.ERROR, err.Error())
		return
	}

	response.Success(c, coupons)
}

// GetUserCoupons 获取用户优惠券
func (h *CouponHandler) GetUserCoupons(c *gin.Context) {
	userIDValue, exists := c.Get("user_id")
	if !exists {
		response.Unauthorized(c)
		return
	}
	userID := userIDValue.(uint)

	status := utils.StringToInt(c.DefaultQuery("status", "1")) // 1未使用，2已使用，3已过期
	coupons, err := h.couponService.GetUserCoupons(userID, status)
	if err != nil {
		response.ErrorWithMessage(c, response.ERROR, err.Error())
		return
	}

	response.Success(c, coupons)
}

// ReceiveCoupon 领取优惠券
func (h *CouponHandler) ReceiveCoupon(c *gin.Context) {
	userIDValue, exists := c.Get("user_id")
	if !exists {
		response.Unauthorized(c)
		return
	}
	userID := userIDValue.(uint)

	couponID := utils.StringToUint(c.Param("id"))
	if couponID == 0 {
		response.BadRequest(c, "无效的优惠券ID")
		return
	}

	err := h.couponService.ReceiveCoupon(userID, couponID)
	if err != nil {
		response.ErrorWithMessage(c, response.ERROR, err.Error())
		return
	}

	response.Success(c, nil)
}

// UseCoupon 使用优惠券
func (h *CouponHandler) UseCoupon(c *gin.Context) {
	userIDValue, exists := c.Get("user_id")
	if !exists {
		response.Unauthorized(c)
		return
	}
	userID := userIDValue.(uint)

	userCouponID := utils.StringToUint(c.Param("id"))
	if userCouponID == 0 {
		response.BadRequest(c, "无效的优惠券ID")
		return
	}

	var req struct {
		OrderID uint `json:"order_id" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "参数错误")
		return
	}

	err := h.couponService.UseCoupon(userID, userCouponID, req.OrderID)
	if err != nil {
		response.ErrorWithMessage(c, response.ERROR, err.Error())
		return
	}

	response.Success(c, nil)
}

// GetAvailableCouponsForOrder 获取订单可用优惠券
func (h *CouponHandler) GetAvailableCouponsForOrder(c *gin.Context) {
	userIDValue, exists := c.Get("user_id")
	if !exists {
		response.Unauthorized(c)
		return
	}
	userID := userIDValue.(uint)

	orderAmountStr := c.Query("order_amount")
	if orderAmountStr == "" {
		response.BadRequest(c, "订单金额不能为空")
		return
	}

	orderAmount := utils.StringToFloat64(orderAmountStr)
	if orderAmount <= 0 {
		response.BadRequest(c, "订单金额必须大于0")
		return
	}

	coupons, err := h.couponService.GetAvailableCouponsForOrder(userID, orderAmount)
	if err != nil {
		response.ErrorWithMessage(c, response.ERROR, err.Error())
		return
	}

	response.Success(c, coupons)
}

// ValidateCoupon 验证优惠券
func (h *CouponHandler) ValidateCoupon(c *gin.Context) {
	userIDValue, exists := c.Get("user_id")
	if !exists {
		response.Unauthorized(c)
		return
	}
	userID := userIDValue.(uint)

	userCouponID := utils.StringToUint(c.Param("id"))
	if userCouponID == 0 {
		response.BadRequest(c, "无效的优惠券ID")
		return
	}

	orderAmountStr := c.Query("order_amount")
	if orderAmountStr == "" {
		response.BadRequest(c, "订单金额不能为空")
		return
	}

	orderAmount := utils.StringToFloat64(orderAmountStr)
	if orderAmount <= 0 {
		response.BadRequest(c, "订单金额必须大于0")
		return
	}

	userCoupon, discountAmount, err := h.couponService.ValidateCoupon(userID, userCouponID, orderAmount)
	if err != nil {
		response.ErrorWithMessage(c, response.ERROR, err.Error())
		return
	}

	result := map[string]interface{}{
		"user_coupon":     userCoupon,
		"discount_amount": discountAmount,
		"can_use":         true,
	}

	response.Success(c, result)
}