<?php
namespace app\service;

use app\model\Order;

class CardService
{
    // 生成 [A-Z][0-9]{3} 格式号码牌，最多重试10次避免冲突
    public function generate(): string
    {
        $maxRetry = 10;
        for ($i = 0; $i < $maxRetry; $i++) {
            $letter = chr(rand(65, 90)); // A-Z
            $num = str_pad(rand(0, 999), 3, '0', STR_PAD_LEFT);
            $cardNo = $letter . $num;
            if ($this->isAvailable($cardNo)) {
                return $cardNo;
            }
        }
        // 冲突过多时追加随机码
        return chr(rand(65, 90)) . str_pad(rand(0, 999), 3, '0', STR_PAD_LEFT) . rand(0, 9);
    }

    // 检查号码牌是否可用（不存在进行中/新单订单）
    public function isAvailable(string $cardNo): bool
    {
        $count = Order::where('card_no', $cardNo)
            ->whereIn('status', [0, 1])
            ->count();
        return $count === 0;
    }

    // 释放号码牌：检查该cardNo是否还有未完成订单
    public function release(string $cardNo): bool
    {
        $count = Order::where('card_no', $cardNo)
            ->whereIn('status', [0, 1])
            ->count();
        return $count === 0; // true=已释放，false=仍占用
    }
}