package handler

import (
	"context"
	"io"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"sync"
	"time"

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

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

var (
	syncOrdersLogger     *log.Logger
	syncOrdersLoggerOnce sync.Once
)

// syncOrdersLogf 将订单同步日志写入 log/sync-orders.log，不输出到控制台
func syncOrdersLogf(format string, args ...interface{}) {
	syncOrdersLoggerOnce.Do(func() {
		_ = os.MkdirAll("log", 0755)
		f, err := os.OpenFile(filepath.Join("log", "sync-orders.log"), os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
		if err != nil {
			syncOrdersLogger = log.New(io.Discard, "", 0)
			return
		}
		syncOrdersLogger = log.New(f, "[SyncOrders] ", log.Ldate|log.Ltime)
	})
	if syncOrdersLogger != nil {
		syncOrdersLogger.Printf(format, args...)
	}
}

// SyncOrdersLogf 供 main 等调用，将订单同步相关日志写入 log/sync-orders.log
func SyncOrdersLogf(format string, args ...interface{}) {
	syncOrdersLogf(format, args...)
}

// processOrderPaidPostProcess 订单已支付后的统一后置逻辑：全书/VIP/匹配/章节权益、取消同商品未支付订单、分佣
func processOrderPaidPostProcess(db *gorm.DB, o *model.Order, transactionID string, totalAmount float64) {
	pt := "fullbook"
	if o.ProductType != "" {
		pt = o.ProductType
	}
	productID := ""
	if o.ProductID != nil {
		productID = *o.ProductID
	}
	if productID == "" {
		productID = "fullbook"
	}
	now := time.Now()

	switch pt {
	case "fullbook":
		db.Model(&model.User{}).Where("id = ?", o.UserID).Update("has_full_book", true)
		syncOrdersLogf("用户已购全书: %s", o.UserID)
	case "vip":
		expireDate := now.AddDate(0, 0, 365)
		db.Model(&model.User{}).Where("id = ?", o.UserID).Updates(map[string]interface{}{
			"is_vip":           true,
			"vip_expire_date":  expireDate,
			"vip_activated_at": now,
		})
		syncOrdersLogf("用户 VIP 已激活: %s, 过期日=%s", o.UserID, expireDate.Format("2006-01-02"))
	case "match":
		syncOrdersLogf("用户购买匹配次数: %s", o.UserID)
	case "section":
		syncOrdersLogf("用户购买章节: %s - %s", o.UserID, productID)
	}

	db.Where(
		"user_id = ? AND product_type = ? AND product_id = ? AND status = ? AND order_sn != ?",
		o.UserID, pt, productID, "created", o.OrderSN,
	).Delete(&model.Order{})

	processReferralCommission(db, o.UserID, totalAmount, o.OrderSN, o)
}

// PollOrderUntilPaidOrTimeout 用户支付发起后，仅轮询该笔订单直到微信返回已支付或超时（防漏单，替代频繁全量扫描）
// 轮询间隔 8 秒，总超时 6 分钟；若微信已支付则更新订单并执行与 PayNotify 一致的后置逻辑
func PollOrderUntilPaidOrTimeout(orderSn string) {
	const pollInterval = 8 * time.Second
	const pollTimeout = 6 * time.Minute
	ctx, cancel := context.WithTimeout(context.Background(), pollTimeout)
	defer cancel()

	db := database.DB()
	for {
		select {
		case <-ctx.Done():
			return
		default:
		}
		qCtx, qCancel := context.WithTimeout(ctx, 15*time.Second)
		tradeState, transactionID, totalFee, qerr := wechat.QueryOrderByOutTradeNo(qCtx, orderSn)
		qCancel()
		if qerr != nil {
			syncOrdersLogf("轮询查询订单 %s 失败: %v", orderSn, qerr)
			time.Sleep(pollInterval)
			continue
		}
		if tradeState == "SUCCESS" {
			var order model.Order
			if err := db.Where("order_sn = ?", orderSn).First(&order).Error; err != nil {
				syncOrdersLogf("轮询订单 %s 查库失败: %v", orderSn, err)
				return
			}
			if order.Status != nil && *order.Status == "paid" {
				return
			}
			now := time.Now()
			if err := db.Model(&order).Updates(map[string]interface{}{
				"status":         "paid",
				"transaction_id": transactionID,
				"pay_time":       now,
				"updated_at":     now,
			}).Error; err != nil {
				syncOrdersLogf("轮询更新订单 %s 失败: %v", orderSn, err)
				return
			}
			totalAmount := float64(totalFee) / 100
			syncOrdersLogf("轮询补齐: %s, amount=%.2f", orderSn, totalAmount)
			processOrderPaidPostProcess(db, &order, transactionID, totalAmount)
			return
		}
		switch tradeState {
		case "CLOSED", "REVOKED", "PAYERROR":
			return
		}
		time.Sleep(pollInterval)
	}
}

// RunSyncOrders 订单对账：查询 status=created 的订单，向微信查询实际状态，若已支付则补齐更新（防漏单）
// 可被 HTTP 接口和内置定时任务调用；日常以 PollOrderUntilPaidOrTimeout 单笔轮询为主，本方法作兜底。
func RunSyncOrders(ctx context.Context, days int) (synced, total int, err error) {
	if days < 1 {
		days = 7
	}
	if days > 30 {
		days = 30
	}
	db := database.DB()
	cutoff := time.Now().AddDate(0, 0, -days)
	var createdOrders []model.Order
	if err := db.Where("status = ? AND created_at > ?", "created", cutoff).Find(&createdOrders).Error; err != nil {
		return 0, 0, err
	}
	total = len(createdOrders)

	for _, o := range createdOrders {
		select {
		case <-ctx.Done():
			return synced, total, ctx.Err()
		default:
		}
		tradeState, transactionID, totalFee, qerr := wechat.QueryOrderByOutTradeNo(ctx, o.OrderSN)
		if qerr != nil {
			syncOrdersLogf("查询订单 %s 失败: %v", o.OrderSN, qerr)
			continue
		}
		if tradeState != "SUCCESS" {
			continue
		}
		totalAmount := float64(totalFee) / 100
		now := time.Now()
		if err := db.Model(&o).Updates(map[string]interface{}{
			"status":         "paid",
			"transaction_id": transactionID,
			"pay_time":       now,
			"updated_at":     now,
		}).Error; err != nil {
			syncOrdersLogf("更新订单 %s 失败: %v", o.OrderSN, err)
			continue
		}
		synced++
		syncOrdersLogf("补齐漏单: %s, amount=%.2f", o.OrderSN, totalAmount)
		processOrderPaidPostProcess(db, &o, transactionID, totalAmount)
	}
	return synced, total, nil
}

// CronSyncOrders GET/POST /api/cron/sync-orders
// 对账：查询 status=created 的订单，向微信查询实际状态，若已支付则补齐更新（防漏单）
// 支持 ?days=7 扩展时间范围，默认 7 天
func CronSyncOrders(c *gin.Context) {
	days := 7
	if d := c.Query("days"); d != "" {
		if n, err := strconv.Atoi(d); err == nil && n > 0 && n <= 30 {
			days = n
		}
	}
	synced, total, err := RunSyncOrders(c.Request.Context(), days)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"synced":  synced,
		"total":   total,
		"days":    days,
	})
}

// CronUnbindExpired GET/POST /api/cron/unbind-expired
func CronUnbindExpired(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{"success": true})
}