<?php

namespace Modules\EcommerceFinance\Services;

use DateTimeInterface;
use Illuminate\Support\Facades\Crypt;
use Illuminate\Support\Facades\URL;
use Throwable;

/**
 * 厂家退货明细的临时免登录链接。
 *
 * 厂家、月份和公司使用加密令牌承载，再由 Laravel 签名绑定 URL，避免通过
 * 修改链接参数查看其他厂家数据。
 */
class SupplierReturnShareLink
{
    public const TTL_DAYS = 30;

    public function pageUrl(int $companyId, string $supplier, string $month): string
    {
        return $this->signedRoute(
            'signed.supplier-returns.show',
            $this->token($companyId, $supplier, $month),
            $companyId,
            now()->addDays(self::TTL_DAYS),
        );
    }

    public function signedRoute(
        string $routeName,
        string $token,
        int $companyId,
        ?DateTimeInterface $expires = null,
    ): string {
        return URL::temporarySignedRoute($routeName, $expires ?? now()->addDays(self::TTL_DAYS), [
            'company_id' => $companyId,
            'token' => $token,
        ]);
    }

    /** @return array{supplier:string,month:string}|null */
    public function resolveToken(string $token, int $companyId): ?array
    {
        try {
            $padding = (4 - strlen($token) % 4) % 4;
            $encoded = strtr($token . str_repeat('=', $padding), '-_', '+/');
            $encrypted = base64_decode($encoded, true);
            if ($encrypted === false) {
                return null;
            }

            $payload = json_decode(Crypt::decryptString($encrypted), true, flags: JSON_THROW_ON_ERROR);
        } catch (Throwable) {
            return null;
        }

        $supplier = is_array($payload) ? trim((string) ($payload['supplier'] ?? '')) : '';
        $month = is_array($payload) ? trim((string) ($payload['month'] ?? '')) : '';
        $payloadCompanyId = is_array($payload) ? (int) ($payload['company_id'] ?? 0) : 0;
        if ($supplier === '' || $payloadCompanyId !== $companyId || preg_match('/^\d{4}-\d{2}$/', $month) !== 1) {
            return null;
        }

        return ['supplier' => $supplier, 'month' => $month];
    }

    private function token(int $companyId, string $supplier, string $month): string
    {
        $payload = json_encode([
            'company_id' => $companyId,
            'supplier' => $supplier,
            'month' => $month,
        ], JSON_UNESCAPED_UNICODE | JSON_THROW_ON_ERROR);

        return rtrim(strtr(base64_encode(Crypt::encryptString($payload)), '+/', '-_'), '=');
    }
}