<?php

namespace app\mzl\modules\jwt\service;

use Firebase\JWT\JWT as FirebaseJWT;
use Firebase\JWT\Key;
use support\exception\BusinessException;

class JwtService
{
    protected $secretKey;
    protected $algorithm;
    protected $issuer;
    protected $expiration;

    public function __construct()
    {
        $this->secretKey = getenv('JWT_SECRET_KEY') ?: 'default_secret_key';
        $this->algorithm = getenv('JWT_ALGORITHM') ?: 'HS256';
        $this->issuer = getenv('JWT_ISSUER') ?: 'domain.com';
        $this->expiration = (int)(getenv('JWT_EXPIRATION') ?: 3600);
    }

    /**
     * 生成 JWT 令牌
     *
     * @param array $payload
     * @return string
     * @throws BusinessException
     */
    public function generateToken(array $payload): string
    {
        $defaultPayload = [
            'iss' => $this->issuer,
            'iat' => time(),
            'nbf' => time(),
            'exp' => time() + $this->expiration,
        ];

        $payload = array_merge($defaultPayload, $payload);

        try {
            return FirebaseJWT::encode($payload, $this->secretKey, $this->algorithm);
        } catch (\Exception $e) {
            throw new BusinessException("令牌生成失败：" . $e->getMessage(), 500);
        }
    }

    /**
     * 验证 JWT 令牌
     *
     * @param string $token
     * @return object
     * @throws BusinessException
     */
    public function verifyToken(string $token)
    {
        try {
            return FirebaseJWT::decode($token, new Key($this->secretKey, $this->algorithm));
        } catch (\Firebase\JWT\ExpiredException $e) {
            throw new BusinessException('令牌已过期', 401);
        } catch (\Firebase\JWT\SignatureInvalidException $e) {
            throw new BusinessException('无效的令牌签名', 401);
        } catch (\Firebase\JWT\BeforeValidException $e) {
            throw new BusinessException('令牌尚未生效', 401);
        } catch (\Exception $e) {
            throw new BusinessException('令牌验证失败：' . $e->getMessage(), 400);
        }
    }
}