package handler

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

	"github.com/gin-gonic/gin"

	membershipservice "wx_service/internal/membership/service"
	"wx_service/internal/middleware"
	"wx_service/internal/model"
)

type RedeemCodeHandler struct {
	svc *membershipservice.RedeemCodeService
}

func NewRedeemCodeHandler(svc *membershipservice.RedeemCodeService) *RedeemCodeHandler {
	return &RedeemCodeHandler{svc: svc}
}

type generateRedeemCodesRequest struct {
	Count        int     `json:"count"`
	Plan         string  `json:"plan"`
	DurationDays int     `json:"duration_days"`
	ExpiresAt    *string `json:"expires_at"`
	MaxUses      int     `json:"max_uses"`
}

func (h *RedeemCodeHandler) Generate(c *gin.Context) {
	adminToken := c.GetHeader("X-Admin-Token")
	if err := h.svc.ValidateAdminToken(adminToken); err != nil {
		switch {
		case errors.Is(err, membershipservice.ErrAdminTokenRequired):
			c.JSON(http.StatusServiceUnavailable, model.Error(http.StatusServiceUnavailable, "未配置后台口令，请联系管理员"))
			return
		default:
			c.JSON(http.StatusUnauthorized, model.Error(http.StatusUnauthorized, "无权限"))
			return
		}
	}

	var req generateRedeemCodesRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, "请求参数错误"))
		return
	}

	var expiresAt *time.Time
	if req.ExpiresAt != nil && *req.ExpiresAt != "" {
		parsed, err := time.ParseInLocation("2006-01-02 15:04:05", *req.ExpiresAt, time.Local)
		if err != nil {
			c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, "expires_at 格式错误，应为 YYYY-MM-DD HH:MM:SS"))
			return
		}
		expiresAt = &parsed
	}

	codes, err := h.svc.Generate(c.Request.Context(), membershipservice.GenerateRedeemCodesRequest{
		Count:        req.Count,
		Plan:         req.Plan,
		DurationDays: req.DurationDays,
		ExpiresAt:    expiresAt,
		MaxUses:      req.MaxUses,
	})
	if err != nil {
		c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, err.Error()))
		return
	}

	c.JSON(http.StatusOK, model.Success(gin.H{
		"count": len(codes),
		"codes": codes,
	}))
}

type redeemRequest struct {
	Code string `json:"code" binding:"required"`
}

func (h *RedeemCodeHandler) Redeem(c *gin.Context) {
	user := middleware.MustCurrentUser(c)

	var req redeemRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, "请求参数错误"))
		return
	}

	res, err := h.svc.Redeem(c.Request.Context(), user, req.Code, c.ClientIP(), c.GetHeader("User-Agent"))
	if err != nil {
		switch {
		case errors.Is(err, membershipservice.ErrRedeemCodeInvalid):
			c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, "兑换码无效"))
			return
		case errors.Is(err, membershipservice.ErrRedeemCodeExpired):
			c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, "兑换码已过期"))
			return
		case errors.Is(err, membershipservice.ErrRedeemCodeUsedUp):
			c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, "兑换码已被使用"))
			return
		case errors.Is(err, membershipservice.ErrRedeemCodeDisabled):
			c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, "兑换码不可用"))
			return
		default:
			c.JSON(http.StatusInternalServerError, model.Error(http.StatusInternalServerError, "兑换失败，请稍后重试"))
			return
		}
	}

	c.JSON(http.StatusOK, model.Success(gin.H{
		"plan":        res.Plan,
		"starts_at":   res.StartsAt,
		"ends_at":     res.EndsAt,
		"extended":    res.Extended,
		"code_suffix": res.CodeSuffix,
	}))
}