package main

import (
	"fmt"
	"log"

	"gorm.io/driver/mysql"
	"gorm.io/gorm"
)

const (
	DbDSN = "root:bindbox2025kdy@tcp(150.158.78.154:3306)/dev_game?charset=utf8mb4&parseTime=True&loc=Local"
)

func main() {
	db, err := gorm.Open(mysql.Open(DbDSN), &gorm.Config{})
	if err != nil {
		log.Fatalf("DB connection failed: %v", err)
	}

	fmt.Println("--- Master Coupon Reconciliation & Repair Generator (Cloud DB) ---")

	var userCoupons []struct {
		ID            int64
		UserID        int64
		CouponID      int64
		BalanceAmount int64
		Status        int32
		ValidEnd      string
		OriginalValue int64
	}

	// Join with system_coupons to get original discount value
	db.Raw(`
		SELECT uc.id, uc.user_id, uc.coupon_id, uc.balance_amount, uc.status, uc.valid_end, sc.discount_value as original_value
		FROM user_coupons uc
		JOIN system_coupons sc ON uc.coupon_id = sc.id
	`).Scan(&userCoupons)

	for _, uc := range userCoupons {
		// Calculate actual usage from ledger
		var ledgerSum int64
		db.Raw("SELECT ABS(SUM(change_amount)) FROM user_coupon_ledger WHERE user_coupon_id = ? AND action = 'apply'", uc.ID).Scan(&ledgerSum)

		// Calculate actual usage from order_coupons
		var orderSum int64
		db.Raw("SELECT SUM(applied_amount) FROM order_coupons WHERE user_coupon_id = ?", uc.ID).Scan(&orderSum)

		// Source of truth: Max of both (covering cases where one might be missing manually)
		actualUsed := ledgerSum
		if orderSum > actualUsed {
			actualUsed = orderSum
		}

		calculatedBalance := uc.OriginalValue - actualUsed
		if calculatedBalance < 0 {
			calculatedBalance = 0
		}

		// Determine correct status
		// 1: Unused (Balance > 0 and Time not past)
		// 2: Used (Balance == 0)
		// 3: Expired (Balance > 0 and Time past)

		expectedStatus := uc.Status
		if calculatedBalance == 0 {
			expectedStatus = 2
		} else {
			// If balance remaining, check time expiry
			// (Assuming valid_end is in RFC3339 or similar from DB)
			// For simplicity in SQL generation, we'll focus on the obvious mismatches found here.
		}

		if calculatedBalance != uc.BalanceAmount || expectedStatus != uc.Status {
			fmt.Printf("-- User %d Coupon %d: Bal %d->%d, Status %v->%v\n",
				uc.UserID, uc.ID, uc.BalanceAmount, calculatedBalance, uc.Status, expectedStatus)
			fmt.Printf("UPDATE user_coupons SET balance_amount = %d, status = %v, updated_at = NOW() WHERE id = %d;\n",
				calculatedBalance, expectedStatus, uc.ID)
		}
	}
}