package handler

import (
	"errors"
	"log"
	"net/http"
	"strings"

	"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"
)

// isMobileUA 判断是否手机浏览器（词表与 pay 侧 handler/order.go 保持一致）。
func isMobileUA(ua string) bool {
	ua = strings.ToLower(ua)
	for _, kw := range []string{"android", "iphone", "ipod", "mobile", "harmony", "windows phone"} {
		if strings.Contains(ua, kw) {
			return true
		}
	}
	return false
}

type PayHandler struct {
	svc *service.PayService
}

func NewPayHandler(svc *service.PayService) *PayHandler {
	return &PayHandler{svc: svc}
}

// Purchase POST /api/v1/license/purchase — 在线购买/续费下单，返回收银台 pay_url。
// 仅管理员可购买（handler 内判权，同 withdraw 模式）。
func (h *PayHandler) Purchase(c *gin.Context) {
	role := middleware.GetRole(c)
	if role != "admin" && role != "superadmin" {
		c.JSON(http.StatusForbidden, gin.H{"error": "仅管理员可购买授权"})
		return
	}
	var req struct {
		BizCode string `json:"biz_code" binding:"required"`
		// 终端类型（可选，"pc"/"mobile"）：App 显式声明优先；缺省按本请求 UA 判断
		// （官网浏览器购买的 UA 是真实终端 UA）。透传给 pay 决定收银台形态。
		ClientType string `json:"client_type" binding:"omitempty,oneof=pc mobile"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	clientType := req.ClientType
	if clientType == "" {
		if isMobileUA(c.Request.UserAgent()) {
			clientType = "mobile"
		} else {
			clientType = "pc"
		}
	}

	res, err := h.svc.CreatePurchase(middleware.GetShopID(c), middleware.GetUserID(c), req.BizCode, clientType)
	if err != nil {
		switch {
		case errors.Is(err, service.ErrPayNotConfigured):
			c.JSON(http.StatusServiceUnavailable, gin.H{"error": err.Error()})
		case errors.Is(err, service.ErrUnknownPlan):
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		case errors.Is(err, service.ErrPromoUsed):
			c.JSON(http.StatusConflict, gin.H{"error": err.Error()})
		default:
			log.Printf("[pay] purchase failed shop=%d biz_code=%s: %v", middleware.GetShopID(c), req.BizCode, err)
			c.JSON(http.StatusBadGateway, gin.H{"error": "下单失败，请稍后重试"})
		}
		return
	}
	util.RespondSuccess(c, res)
}

// PurchaseStatus GET /api/v1/license/purchase/:out_trade_no — 结果页轮询购买单状态。
func (h *PayHandler) PurchaseStatus(c *gin.Context) {
	st, err := h.svc.Status(middleware.GetShopID(c), c.Param("out_trade_no"))
	if err != nil {
		if errors.Is(err, service.ErrPurchaseNotFound) {
			c.JSON(http.StatusNotFound, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	util.RespondSuccess(c, st)
}

// PromoStatus GET /api/v1/license/promo-status — 本店首月特惠是否已享用（前端据此置灰特惠档）。
func (h *PayHandler) PromoStatus(c *gin.Context) {
	used, err := h.svc.PromoUsed(middleware.GetShopID(c))
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	util.RespondSuccess(c, gin.H{"used": used})
}

// Callback POST /api/v1/pay/callback — pay 支付成功 webhook（公开路由，HMAC 验签）。
// 契约：验签失败回 401；受理成功回 200 + {"code":"SUCCESS"}，否则 pay 每 60s 重试 24h。
func (h *PayHandler) Callback(c *gin.Context) {
	rawBody, err := c.GetRawData()
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": "FAIL", "message": "read body failed"})
		return
	}
	err = h.svc.HandleCallback(rawBody,
		c.GetHeader("X-Pay-Timestamp"), c.GetHeader("X-Pay-Nonce"), c.GetHeader("X-Pay-Sign"))
	if err != nil {
		if errors.Is(err, service.ErrPaySignature) {
			c.JSON(http.StatusUnauthorized, gin.H{"code": "FAIL", "message": "signature verification failed"})
			return
		}
		// 其余错误（暂时性/金额不符/单不存在）回非 SUCCESS，让 pay 重试；金额不符会持续失败并留日志告警
		log.Printf("[pay] callback rejected: %v", err)
		c.JSON(http.StatusOK, gin.H{"code": "FAIL", "message": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"code": "SUCCESS"})
}