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("--- Advanced Coupon Data Reconciliation (Cloud DB) ---")

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

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

	fmt.Println("Generating repair SQL based on ledger and order association...")

	for _, uc := range userCoupons {
		// Calculate total deduction from ledger
		var totalDeduction struct {
			Sum int64
		}
		db.Raw("SELECT ABS(SUM(change_amount)) as sum FROM user_coupon_ledger WHERE user_coupon_id = ? AND action = 'apply'", uc.ID).Scan(&totalDeduction)

		// Calculate total deduction from order_coupons (secondary verification)
		var orderDeduction struct {
			Sum int64
		}
		db.Raw("SELECT SUM(applied_amount) as sum FROM order_coupons WHERE user_coupon_id = ?", uc.ID).Scan(&orderDeduction)

		// Choose the source of truth (ledger usually preferred)
		actualUsed := totalDeduction.Sum
		if orderDeduction.Sum > actualUsed {
			actualUsed = orderDeduction.Sum
		}

		expectedBalance := uc.SystemAmount - actualUsed
		if expectedBalance < 0 {
			expectedBalance = 0
		}

		expectedStatus := uc.Status
		if expectedBalance == 0 {
			expectedStatus = 2 // Fully Used
		} else if expectedBalance > 0 {
			// Check if it should be expired or unused
			// We won't downgrade Expired (3) back to Unused (1) unless balance > 0 and time is not up.
			// However, usually if balance > 0 and Status is 2, it's a bug.
		}

		// Check for status 3 that shouldn't be
		// (Currently the user says they see status 3 but it's used?)
		// If balance == 0, status must be 2.

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