package handler

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strings"
	"time"
	"unicode/utf8"

	"soul-api/internal/database"
	"soul-api/internal/model"
	"soul-api/internal/wechat"

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

const giftPayExpireHours = 24

// giftPayPreviewContent 取内容前 20%，用于代付页营销展示
func giftPayPreviewContent(content string) string {
	n := utf8.RuneCountInString(content)
	if n == 0 {
		return ""
	}
	limit := n * 20 / 100
	if limit < 50 {
		limit = 50
	}
	if limit > n {
		limit = n
	}
	runes := []rune(content)
	if limit >= n {
		return string(runes)
	}
	return string(runes[:limit]) + "……"
}

// GiftPayCreate POST /api/miniprogram/gift-pay/create 创建代付请求
func GiftPayCreate(c *gin.Context) {
	var req struct {
		UserID      string `json:"userId" binding:"required"`
		ProductType string `json:"productType" binding:"required"`
		ProductID   string `json:"productId"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "缺少参数"})
		return
	}
	db := database.DB()

	// 校验发起人
	var initiator model.User
	if err := db.Where("id = ?", req.UserID).First(&initiator).Error; err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "用户不存在"})
		return
	}

	// 价格与商品校验
	productID := req.ProductID
	if productID == "" {
		switch req.ProductType {
		case "vip":
			productID = "vip_annual"
		case "match":
			productID = "match"
		case "fullbook":
			productID = "fullbook"
		}
	}
	amount, priceErr := getStandardPrice(db, req.ProductType, productID)
	if priceErr != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": priceErr.Error()})
		return
	}
	// 发起人若有推荐人绑定，享受好友优惠
	var referrerID *string
	var binding struct {
		ReferrerID string `gorm:"column:referrer_id"`
	}
	if err := db.Raw(`
		SELECT referrer_id FROM referral_bindings
		WHERE referee_id = ? AND status = 'active' AND expiry_date > NOW()
		ORDER BY binding_date DESC LIMIT 1
	`, req.UserID).Scan(&binding).Error; err == nil && binding.ReferrerID != "" {
		referrerID = &binding.ReferrerID
		var cfg model.SystemConfig
		if err := db.Where("config_key = ?", "referral_config").First(&cfg).Error; err == nil {
			var config map[string]interface{}
			if json.Unmarshal(cfg.ConfigValue, &config) == nil {
				if userDiscount, ok := config["userDiscount"].(float64); ok && userDiscount > 0 {
					amount = amount * (1 - userDiscount/100)
					if amount < 0.01 {
						amount = 0.01
					}
				}
			}
		}
	}
	_ = referrerID // 分佣在 PayNotify 时按发起人计算

	// 校验发起人是否已拥有
	if req.ProductType == "section" && productID != "" {
		var cnt int64
		db.Model(&model.Order{}).Where("user_id = ? AND product_type = ? AND product_id = ? AND status IN ?",
			req.UserID, "section", productID, []string{"paid", "completed"}).Count(&cnt)
		if cnt > 0 {
			c.JSON(http.StatusOK, gin.H{"success": false, "error": "您已拥有该章节"})
			return
		}
	}
	if req.ProductType == "fullbook" || req.ProductType == "vip" {
		var u model.User
		db.Where("id = ?", req.UserID).Select("has_full_book", "is_vip", "vip_expire_date").First(&u)
		if u.HasFullBook != nil && *u.HasFullBook {
			c.JSON(http.StatusOK, gin.H{"success": false, "error": "您已拥有全书"})
			return
		}
		if req.ProductType == "vip" && u.IsVip != nil && *u.IsVip && u.VipExpireDate != nil && u.VipExpireDate.After(time.Now()) {
			c.JSON(http.StatusOK, gin.H{"success": false, "error": "您已是有效VIP"})
			return
		}
	}

	// 描述
	desc := ""
	switch req.ProductType {
	case "fullbook":
		desc = "《一场Soul的创业实验》全书"
	case "vip":
		desc = "卡若创业派对VIP年度会员（365天）"
	case "match":
		desc = "购买匹配次数"
	case "section":
		var ch model.Chapter
		if err := db.Select("section_title").Where("id = ?", productID).First(&ch).Error; err == nil && ch.SectionTitle != "" {
			desc = ch.SectionTitle
		} else {
			desc = fmt.Sprintf("章节-%s", productID)
		}
	default:
		desc = fmt.Sprintf("%s-%s", req.ProductType, productID)
	}

	expireAt := time.Now().Add(giftPayExpireHours * time.Hour)
	requestSN := "GPR" + wechat.GenerateOrderSn()
	id := "gpr_" + fmt.Sprintf("%d", time.Now().UnixNano()%100000000000)

	gpr := model.GiftPayRequest{
		ID:              id,
		RequestSN:       requestSN,
		InitiatorUserID: req.UserID,
		ProductType:     req.ProductType,
		ProductID:       productID,
		Amount:          amount,
		Description:    desc,
		Status:          "pending",
		ExpireAt:        expireAt,
	}
	if err := db.Create(&gpr).Error; err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "创建失败"})
		return
	}

	path := fmt.Sprintf("pages/gift-pay/detail?requestSn=%s", requestSN)
	c.JSON(http.StatusOK, gin.H{
		"success":   true,
		"requestSn": requestSN,
		"path":      path,
		"amount":    amount,
		"expireAt":  expireAt.Format(time.RFC3339),
	})
}

// GiftPayDetail GET /api/miniprogram/gift-pay/detail?requestSn=xxx 代付详情（代付人用）
func GiftPayDetail(c *gin.Context) {
	requestSn := strings.TrimSpace(c.Query("requestSn"))
	if requestSn == "" {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "缺少代付请求号"})
		return
	}
	db := database.DB()

	var gpr model.GiftPayRequest
	if err := db.Where("request_sn = ?", requestSn).First(&gpr).Error; err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "代付请求不存在"})
		return
	}

	if gpr.Status != "pending" {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "该代付已处理"})
		return
	}
	if time.Now().After(gpr.ExpireAt) {
		db.Model(&gpr).Update("status", "expired")
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "代付已过期"})
		return
	}

	// 发起人昵称（脱敏）
	var initiator model.User
	nickname := "好友"
	if err := db.Where("id = ?", gpr.InitiatorUserID).Select("nickname").First(&initiator).Error; err == nil && initiator.Nickname != nil {
		n := *initiator.Nickname
		if len(n) > 2 {
			n = string([]rune(n)[0]) + "**"
		}
		nickname = n
	}

	// 营销：章节类型时返回标题和内容预览，吸引代付人
	sectionTitle := gpr.Description
	contentPreview := ""
	if gpr.ProductType == "section" && gpr.ProductID != "" {
		var ch model.Chapter
		if err := db.Select("section_title", "content").Where("id = ?", gpr.ProductID).First(&ch).Error; err == nil {
			if ch.SectionTitle != "" {
				sectionTitle = ch.SectionTitle
			}
			contentPreview = giftPayPreviewContent(ch.Content)
		}
	}

	c.JSON(http.StatusOK, gin.H{
		"success":           true,
		"requestSn":         gpr.RequestSN,
		"productType":       gpr.ProductType,
		"productId":        gpr.ProductID,
		"amount":            gpr.Amount,
		"description":       gpr.Description,
		"sectionTitle":      sectionTitle,
		"contentPreview":    contentPreview,
		"initiatorNickname": nickname,
		"initiatorUserId":   gpr.InitiatorUserID,
		"expireAt":          gpr.ExpireAt.Format(time.RFC3339),
	})
}

// GiftPayPay POST /api/miniprogram/gift-pay/pay 代付人发起支付
func GiftPayPay(c *gin.Context) {
	var req struct {
		RequestSn string `json:"requestSn" binding:"required"`
		OpenID    string `json:"openId" binding:"required"`
		UserID    string `json:"userId"` // 代付人ID，用于校验不能自己付
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "缺少参数"})
		return
	}
	db := database.DB()

	var gpr model.GiftPayRequest
	if err := db.Where("request_sn = ? AND status = ?", req.RequestSn, "pending").First(&gpr).Error; err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "代付请求不存在或已处理"})
		return
	}
	if time.Now().After(gpr.ExpireAt) {
		db.Model(&gpr).Update("status", "expired")
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "代付已过期"})
		return
	}

	// 不能自己给自己代付
	if req.UserID != "" && req.UserID == gpr.InitiatorUserID {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "不能为自己代付"})
		return
	}

	// 获取代付人信息
	var payer model.User
	if err := db.Where("open_id = ?", req.OpenID).First(&payer).Error; err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "请先登录"})
		return
	}
	if payer.ID == gpr.InitiatorUserID {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "不能为自己代付"})
		return
	}

	// 创建订单（归属发起人，记录代付信息）
	orderSn := wechat.GenerateOrderSn()
	status := "created"
	pm := "wechat"
	productID := gpr.ProductID
	desc := gpr.Description
	gprID := gpr.ID
	payerID := payer.ID
	order := model.Order{
		ID:                 orderSn,
		OrderSN:            orderSn,
		UserID:             gpr.InitiatorUserID,
		OpenID:             req.OpenID,
		ProductType:        gpr.ProductType,
		ProductID:          &productID,
		Amount:             gpr.Amount,
		Description:        &desc,
		Status:             &status,
		PaymentMethod:      &pm,
		GiftPayRequestID:   &gprID,
		PayerUserID:        &payerID,
	}
	if err := db.Create(&order).Error; err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "创建订单失败"})
		return
	}

	// 唤起微信支付，attach 中 userId=发起人，giftPayRequestSn=请求号
	attach := fmt.Sprintf(`{"productType":"%s","productId":"%s","userId":"%s","giftPayRequestSn":"%s"}`,
		gpr.ProductType, gpr.ProductID, gpr.InitiatorUserID, gpr.RequestSN)
	totalFee := int(gpr.Amount * 100)
	ctx := c.Request.Context()
	prepayID, err := wechat.PayJSAPIOrder(ctx, req.OpenID, orderSn, totalFee, "代付-"+gpr.Description, attach)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": fmt.Sprintf("支付请求失败: %v", err)})
		return
	}
	payParams, err := wechat.GetJSAPIPayParams(prepayID)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "生成支付参数失败"})
		return
	}

	// 预占：更新请求状态为 paying（可选，防并发）
	// 简化：不预占，PayNotify 时再更新

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"data": gin.H{
			"orderSn":   orderSn,
			"prepayId":  prepayID,
			"payParams": payParams,
		},
	})
}

// GiftPayCancel POST /api/miniprogram/gift-pay/cancel 发起人取消
func GiftPayCancel(c *gin.Context) {
	var req struct {
		RequestSn string `json:"requestSn" binding:"required"`
		UserID    string `json:"userId" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "缺少参数"})
		return
	}
	db := database.DB()

	var gpr model.GiftPayRequest
	if err := db.Where("request_sn = ?", req.RequestSn).First(&gpr).Error; err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "代付请求不存在"})
		return
	}
	if gpr.InitiatorUserID != req.UserID {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "无权取消"})
		return
	}
	if gpr.Status != "pending" {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "该代付已处理"})
		return
	}

	db.Model(&gpr).Update("status", "cancelled")
	c.JSON(http.StatusOK, gin.H{"success": true, "message": "已取消"})
}

// GiftPayMyRequests GET /api/miniprogram/gift-pay/my-requests?userId= 我发起的
func GiftPayMyRequests(c *gin.Context) {
	userID := c.Query("userId")
	if userID == "" {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "缺少userId"})
		return
	}
	db := database.DB()

	var list []model.GiftPayRequest
	db.Where("initiator_user_id = ?", userID).Order("created_at DESC").Limit(50).Find(&list)

	out := make([]gin.H, 0, len(list))
	for _, r := range list {
		out = append(out, gin.H{
			"requestSn": r.RequestSN,
			"productType": r.ProductType,
			"productId":   r.ProductID,
			"amount":      r.Amount,
			"description": r.Description,
			"status":      r.Status,
			"expireAt":    r.ExpireAt.Format(time.RFC3339),
			"createdAt":   r.CreatedAt.Format(time.RFC3339),
		})
	}
	c.JSON(http.StatusOK, gin.H{"success": true, "list": out})
}

// GiftPayMyPayments GET /api/miniprogram/gift-pay/my-payments?userId= 我帮付的
func GiftPayMyPayments(c *gin.Context) {
	userID := c.Query("userId")
	if userID == "" {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "缺少userId"})
		return
	}
	db := database.DB()

	var list []model.GiftPayRequest
	db.Where("payer_user_id = ?", userID).Order("created_at DESC").Limit(50).Find(&list)

	out := make([]gin.H, 0, len(list))
	for _, r := range list {
		out = append(out, gin.H{
			"requestSn":   r.RequestSN,
			"productType": r.ProductType,
			"amount":      r.Amount,
			"description": r.Description,
			"status":      r.Status,
			"createdAt":   r.CreatedAt.Format(time.RFC3339),
		})
	}
	c.JSON(http.StatusOK, gin.H{"success": true, "list": out})
}