package handler

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

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

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

// MiniprogramLogin POST /api/miniprogram/login
func MiniprogramLogin(c *gin.Context) {
	var req struct {
		Code string `json:"code" binding:"required"`
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "缺少登录code"})
		return
	}

	// 调用微信接口获取 openid 和 session_key
	openID, sessionKey, _, err := wechat.Code2Session(req.Code)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": fmt.Sprintf("微信登录失败: %v", err)})
		return
	}

	db := database.DB()
	
	// 查询用户是否存在
	var user model.User
	result := db.Where("open_id = ?", openID).First(&user)
	
	isNewUser := result.Error != nil
	
	if isNewUser {
		// 创建新用户
		userID := openID // 直接使用 openid 作为用户 ID
		referralCode := "SOUL" + strings.ToUpper(openID[len(openID)-6:])
		nickname := "微信用户" + openID[len(openID)-4:]
		avatar := ""
		hasFullBook := false
		earnings := 0.0
		pendingEarnings := 0.0
		referralCount := 0
		purchasedSections := "[]"
		
		user = model.User{
			ID:                userID,
			OpenID:            &openID,
			SessionKey:        &sessionKey,
			Nickname:          &nickname,
			Avatar:            &avatar,
			ReferralCode:      &referralCode,
			HasFullBook:       &hasFullBook,
			PurchasedSections: &purchasedSections,
			Earnings:          &earnings,
			PendingEarnings:   &pendingEarnings,
			ReferralCount:     &referralCount,
		}
		
		if err := db.Create(&user).Error; err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": "创建用户失败"})
			return
		}
	} else {
		// 更新 session_key
		db.Model(&user).Update("session_key", sessionKey)
	}

	// 从 orders 表查询真实购买记录
	var purchasedSections []string
	var orderRows []struct {
		ProductID string `gorm:"column:product_id"`
	}
	
	db.Raw(`
		SELECT DISTINCT product_id 
		FROM orders 
		WHERE user_id = ? 
		  AND status = 'paid' 
		  AND product_type = 'section'
	`, user.ID).Scan(&orderRows)
	
	for _, row := range orderRows {
		if row.ProductID != "" {
			purchasedSections = append(purchasedSections, row.ProductID)
		}
	}
	
	if purchasedSections == nil {
		purchasedSections = []string{}
	}

	// 构建返回的用户对象
	responseUser := map[string]interface{}{
		"id":               user.ID,
		"openId":           getStringValue(user.OpenID),
		"nickname":         getStringValue(user.Nickname),
		"avatar":           getStringValue(user.Avatar),
		"phone":            getStringValue(user.Phone),
		"wechatId":         getStringValue(user.WechatID),
		"referralCode":     getStringValue(user.ReferralCode),
		"hasFullBook":      getBoolValue(user.HasFullBook),
		"purchasedSections": purchasedSections,
		"earnings":         getFloatValue(user.Earnings),
		"pendingEarnings":  getFloatValue(user.PendingEarnings),
		"referralCount":    getIntValue(user.ReferralCount),
		"createdAt":        user.CreatedAt,
	}

	// 生成 token
	token := fmt.Sprintf("tk_%s_%d", openID[len(openID)-8:], time.Now().Unix())

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"data": map[string]interface{}{
			"openId": openID,
			"user":   responseUser,
			"token":  token,
		},
		"isNewUser": isNewUser,
	})
}

// 辅助函数
func getStringValue(ptr *string) string {
	if ptr == nil {
		return ""
	}
	return *ptr
}

func getBoolValue(ptr *bool) bool {
	if ptr == nil {
		return false
	}
	return *ptr
}

func getFloatValue(ptr *float64) float64 {
	if ptr == nil {
		return 0.0
	}
	return *ptr
}

func getIntValue(ptr *int) int {
	if ptr == nil {
		return 0
	}
	return *ptr
}

// MiniprogramPay GET/POST /api/miniprogram/pay
func MiniprogramPay(c *gin.Context) {
	if c.Request.Method == "POST" {
		miniprogramPayPost(c)
	} else {
		miniprogramPayGet(c)
	}
}

// POST - 创建小程序支付订单
func miniprogramPayPost(c *gin.Context) {
	var req struct {
		OpenID        string  `json:"openId" binding:"required"`
		ProductType   string  `json:"productType" binding:"required"`
		ProductID     string  `json:"productId"`
		Amount        float64 `json:"amount" binding:"required"`
		Description   string  `json:"description"`
		UserID        string  `json:"userId"`
		ReferralCode  string  `json:"referralCode"`
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "缺少openId参数，请先登录"})
		return
	}

	if req.Amount <= 0 {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "支付金额无效"})
		return
	}

	db := database.DB()
	
	// 获取推广配置计算好友优惠
	finalAmount := req.Amount
	if req.ReferralCode != "" {
		var cfg model.SystemConfig
		if err := db.Where("config_key = ?", "referral_config").First(&cfg).Error; err == nil {
			var config map[string]interface{}
			if err := json.Unmarshal(cfg.ConfigValue, &config); err == nil {
				if userDiscount, ok := config["userDiscount"].(float64); ok && userDiscount > 0 {
					discountRate := userDiscount / 100
					finalAmount = req.Amount * (1 - discountRate)
					if finalAmount < 0.01 {
						finalAmount = 0.01
					}
				}
			}
		}
	}

	// 生成订单号
	orderSn := wechat.GenerateOrderSn()
	totalFee := int(finalAmount * 100) // 转为分
	description := req.Description
	if description == "" {
		if req.ProductType == "fullbook" {
			description = "《一场Soul的创业实验》全书"
		} else {
			description = fmt.Sprintf("章节购买-%s", req.ProductID)
		}
	}

	// 获取客户端 IP
	clientIP := c.ClientIP()
	if clientIP == "" {
		clientIP = "127.0.0.1"
	}

	// 查询用户的有效推荐人
	var referrerID *string
	if req.UserID != "" {
		var binding struct {
			ReferrerID string `gorm:"column:referrer_id"`
		}
		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
		
		if err == nil && binding.ReferrerID != "" {
			referrerID = &binding.ReferrerID
		}
	}

	// 如果没有绑定，尝试从邀请码解析推荐人
	if referrerID == nil && req.ReferralCode != "" {
		var refUser model.User
		if err := db.Where("referral_code = ?", req.ReferralCode).First(&refUser).Error; err == nil {
			referrerID = &refUser.ID
		}
	}

	// 插入订单到数据库
	userID := req.UserID
	if userID == "" {
		userID = req.OpenID
	}
	
	productID := req.ProductID
	if productID == "" {
		productID = "fullbook"
	}
	
	status := "created"
	order := model.Order{
		ID:            orderSn,
		OrderSN:       orderSn,
		UserID:        userID,
		OpenID:        req.OpenID,
		ProductType:   req.ProductType,
		ProductID:     &productID,
		Amount:        finalAmount,
		Description:   &description,
		Status:        &status,
		ReferrerID:    referrerID,
		ReferralCode:  &req.ReferralCode,
	}
	
	if err := db.Create(&order).Error; err != nil {
		// 订单创建失败，但不中断支付流程
		fmt.Printf("[MiniprogramPay] 插入订单失败: %v\n", err)
	}

	attach := fmt.Sprintf(`{"productType":"%s","productId":"%s","userId":"%s"}`, req.ProductType, req.ProductID, userID)
	ctx := c.Request.Context()
	prepayID, err := wechat.PayJSAPIOrder(ctx, req.OpenID, orderSn, totalFee, description, attach)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": fmt.Sprintf("微信支付请求失败: %v", err)})
		return
	}
	payParams, err := wechat.GetJSAPIPayParams(prepayID)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": fmt.Sprintf("生成支付参数失败: %v", err)})
		return
	}

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

// GET - 查询订单状态
func miniprogramPayGet(c *gin.Context) {
	orderSn := c.Query("orderSn")
	if orderSn == "" {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "缺少订单号"})
		return
	}

	ctx := c.Request.Context()
	tradeState, transactionID, totalFee, err := wechat.QueryOrderByOutTradeNo(ctx, orderSn)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": true,
			"data": map[string]interface{}{
				"status":  "unknown",
				"orderSn": orderSn,
			},
		})
		return
	}

	status := "paying"
	switch tradeState {
	case "SUCCESS":
		status = "paid"
	case "CLOSED", "REVOKED", "PAYERROR":
		status = "failed"
	case "REFUND":
		status = "refunded"
	}

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"data": map[string]interface{}{
			"status":        status,
			"orderSn":       orderSn,
			"transactionId": transactionID,
			"totalFee":      totalFee,
		},
	})
}

// MiniprogramPayNotify POST /api/miniprogram/pay/notify（v3 支付回调，PowerWeChat 验签解密）
func MiniprogramPayNotify(c *gin.Context) {
	resp, err := wechat.HandlePayNotify(c.Request, func(orderSn, transactionID string, totalFee int, attachStr, openID string) error {
		totalAmount := float64(totalFee) / 100
		fmt.Printf("[PayNotify] 支付成功: orderSn=%s, transactionId=%s, amount=%.2f\n", orderSn, transactionID, totalAmount)

		var attach struct {
			ProductType string `json:"productType"`
			ProductID   string `json:"productId"`
			UserID      string `json:"userId"`
		}
		if attachStr != "" {
			_ = json.Unmarshal([]byte(attachStr), &attach)
		}

		db := database.DB()
		buyerUserID := attach.UserID
		if openID != "" {
			var user model.User
			if err := db.Where("open_id = ?", openID).First(&user).Error; err == nil {
				if attach.UserID != "" && user.ID != attach.UserID {
					fmt.Printf("[PayNotify] 买家身份校验: attach.userId 与 openId 解析不一致，以 openId 为准\n")
				}
				buyerUserID = user.ID
			}
		}
		if buyerUserID == "" && attach.UserID != "" {
			buyerUserID = attach.UserID
		}

		var order model.Order
		result := db.Where("order_sn = ?", orderSn).First(&order)
		if result.Error != nil {
			fmt.Printf("[PayNotify] 订单不存在，补记订单: %s\n", orderSn)
			productID := attach.ProductID
			if productID == "" {
				productID = "fullbook"
			}
			productType := attach.ProductType
			if productType == "" {
				productType = "unknown"
			}
			desc := "支付回调补记订单"
			status := "paid"
			now := time.Now()
			order = model.Order{
				ID:            orderSn,
				OrderSN:       orderSn,
				UserID:        buyerUserID,
				OpenID:        openID,
				ProductType:   productType,
				ProductID:     &productID,
				Amount:        totalAmount,
				Description:   &desc,
				Status:        &status,
				TransactionID: &transactionID,
				PayTime:       &now,
			}
			db.Create(&order)
		} else if *order.Status != "paid" {
			status := "paid"
			now := time.Now()
			db.Model(&order).Updates(map[string]interface{}{
				"status":         status,
				"transaction_id": transactionID,
				"pay_time":       now,
			})
			fmt.Printf("[PayNotify] 订单状态已更新为已支付: %s\n", orderSn)
		} else {
			fmt.Printf("[PayNotify] 订单已支付，跳过更新: %s\n", orderSn)
		}

		if buyerUserID != "" && attach.ProductType != "" {
			if attach.ProductType == "fullbook" {
				db.Model(&model.User{}).Where("id = ?", buyerUserID).Update("has_full_book", true)
				fmt.Printf("[PayNotify] 用户已购全书: %s\n", buyerUserID)
			} else if attach.ProductType == "section" && attach.ProductID != "" {
				var count int64
				db.Model(&model.Order{}).Where(
					"user_id = ? AND product_type = 'section' AND product_id = ? AND status = 'paid' AND order_sn != ?",
					buyerUserID, attach.ProductID, orderSn,
				).Count(&count)
				if count == 0 {
					fmt.Printf("[PayNotify] 用户首次购买章节: %s - %s\n", buyerUserID, attach.ProductID)
				} else {
					fmt.Printf("[PayNotify] 用户已有该章节的其他已支付订单: %s - %s\n", buyerUserID, attach.ProductID)
				}
			}
			productID := attach.ProductID
			if productID == "" {
				productID = "fullbook"
			}
			db.Where(
				"user_id = ? AND product_type = ? AND product_id = ? AND status = 'created' AND order_sn != ?",
				buyerUserID, attach.ProductType, productID, orderSn,
			).Delete(&model.Order{})
			processReferralCommission(db, buyerUserID, totalAmount, orderSn)
		}
		return nil
	})
	if err != nil {
		fmt.Printf("[PayNotify] 处理回调失败: %v\n", err)
		c.String(http.StatusOK, failResponse())
		return
	}
	defer resp.Body.Close()
	for k, v := range resp.Header {
		if len(v) > 0 {
			c.Header(k, v[0])
		}
	}
	c.Status(resp.StatusCode)
	io.Copy(c.Writer, resp.Body)
}

// 处理分销佣金
func processReferralCommission(db *gorm.DB, buyerUserID string, amount float64, orderSn string) {
	// 获取分成配置，默认 90%
	distributorShare := 0.9
	var cfg model.SystemConfig
	if err := db.Where("config_key = ?", "referral_config").First(&cfg).Error; err == nil {
		var config map[string]interface{}
		if err := json.Unmarshal(cfg.ConfigValue, &config); err == nil {
			if share, ok := config["distributorShare"].(float64); ok {
				distributorShare = share / 100
			}
		}
	}

	// 查找有效推广绑定
	type Binding struct {
		ID              int       `gorm:"column:id"`
		ReferrerID      string    `gorm:"column:referrer_id"`
		ExpiryDate      time.Time `gorm:"column:expiry_date"`
		PurchaseCount   int       `gorm:"column:purchase_count"`
		TotalCommission float64   `gorm:"column:total_commission"`
	}
	
	var binding Binding
	err := db.Raw(`
		SELECT id, referrer_id, expiry_date, purchase_count, total_commission
		FROM referral_bindings
		WHERE referee_id = ? AND status = 'active'
		ORDER BY binding_date DESC
		LIMIT 1
	`, buyerUserID).Scan(&binding).Error
	
	if err != nil {
		fmt.Printf("[PayNotify] 用户无有效推广绑定，跳过分佣: %s\n", buyerUserID)
		return
	}

	// 检查是否过期
	if time.Now().After(binding.ExpiryDate) {
		fmt.Printf("[PayNotify] 绑定已过期，跳过分佣: %s\n", buyerUserID)
		return
	}

	// 计算佣金
	commission := amount * distributorShare
	newPurchaseCount := binding.PurchaseCount + 1
	newTotalCommission := binding.TotalCommission + commission
	
	fmt.Printf("[PayNotify] 处理分佣: referrerId=%s, amount=%.2f, commission=%.2f, shareRate=%.0f%%\n",
		binding.ReferrerID, amount, commission, distributorShare*100)

	// 更新推广者的待结算收益
	db.Model(&model.User{}).Where("id = ?", binding.ReferrerID).
		Update("pending_earnings", db.Raw("pending_earnings + ?", commission))

	// 更新绑定记录
	db.Exec(`
		UPDATE referral_bindings 
		SET last_purchase_date = NOW(),
		    purchase_count = purchase_count + 1,
		    total_commission = total_commission + ?
		WHERE id = ?
	`, commission, binding.ID)

	fmt.Printf("[PayNotify] 分佣完成: 推广者 %s 获得 %.2f 元（第 %d 次购买，累计 %.2f 元）\n",
		binding.ReferrerID, commission, newPurchaseCount, newTotalCommission)
}

// 微信支付回调响应
func successResponse() string {
	return `<xml><return_code><![CDATA[SUCCESS]]></return_code><return_msg><![CDATA[OK]]></return_msg></xml>`
}

func failResponse() string {
	return `<xml><return_code><![CDATA[FAIL]]></return_code><return_msg><![CDATA[ERROR]]></return_msg></xml>`
}

// MiniprogramPhone POST /api/miniprogram/phone
func MiniprogramPhone(c *gin.Context) {
	var req struct {
		Code   string `json:"code" binding:"required"`
		UserID string `json:"userId"`
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "message": "缺少code参数"})
		return
	}

	// 获取手机号
	phoneNumber, countryCode, err := wechat.GetPhoneNumber(req.Code)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"message": "获取手机号失败",
			"error":   err.Error(),
		})
		return
	}

	// 如果提供了 userId，更新到数据库
	if req.UserID != "" {
		db := database.DB()
		db.Model(&model.User{}).Where("id = ?", req.UserID).Update("phone", phoneNumber)
		fmt.Printf("[MiniprogramPhone] 手机号已绑定到用户: %s\n", req.UserID)
	}

	c.JSON(http.StatusOK, gin.H{
		"success":     true,
		"phoneNumber": phoneNumber,
		"countryCode": countryCode,
	})
}

// MiniprogramQrcode POST /api/miniprogram/qrcode
func MiniprogramQrcode(c *gin.Context) {
	var req struct {
		Scene     string `json:"scene"`
		Page      string `json:"page"`
		Width     int    `json:"width"`
		ChapterID string `json:"chapterId"`
		UserID    string `json:"userId"`
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "参数错误"})
		return
	}

	// 构建 scene 参数
	scene := req.Scene
	if scene == "" {
		var parts []string
		if req.UserID != "" {
			userId := req.UserID
			if len(userId) > 15 {
				userId = userId[:15]
			}
			parts = append(parts, fmt.Sprintf("ref=%s", userId))
		}
		if req.ChapterID != "" {
			parts = append(parts, fmt.Sprintf("ch=%s", req.ChapterID))
		}
		if len(parts) == 0 {
			scene = "soul"
		} else {
			scene = strings.Join(parts, "&")
		}
	}

	page := req.Page
	if page == "" {
		page = "pages/index/index"
	}

	width := req.Width
	if width == 0 {
		width = 280
	}

	fmt.Printf("[MiniprogramQrcode] 生成小程序码, scene=%s\n", scene)

	// 生成小程序码
	imageData, err := wechat.GenerateMiniProgramCode(scene, page, width)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"error":   fmt.Sprintf("生成小程序码失败: %v", err),
		})
		return
	}

	// 转换为 base64
	base64Image := fmt.Sprintf("data:image/png;base64,%s", base64Encode(imageData))

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"image":   base64Image,
		"scene":   scene,
	})
}

// base64 编码
func base64Encode(data []byte) string {
	const base64Table = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
	var result strings.Builder
	
	for i := 0; i < len(data); i += 3 {
		b1, b2, b3 := data[i], byte(0), byte(0)
		if i+1 < len(data) {
			b2 = data[i+1]
		}
		if i+2 < len(data) {
			b3 = data[i+2]
		}
		
		result.WriteByte(base64Table[b1>>2])
		result.WriteByte(base64Table[((b1&0x03)<<4)|(b2>>4)])
		
		if i+1 < len(data) {
			result.WriteByte(base64Table[((b2&0x0F)<<2)|(b3>>6)])
		} else {
			result.WriteByte('=')
		}
		
		if i+2 < len(data) {
			result.WriteByte(base64Table[b3&0x3F])
		} else {
			result.WriteByte('=')
		}
	}
	
	return result.String()
}