<?php

namespace App\Service\common;

use Firebase\JWT\JWT;
use Firebase\JWT\Key;
use Exception;

class JWTService
{
    private static mixed $_instance;
    private string $secretKey = 'cc_spa_jwt_secret_key'; // 请替换为你的密钥

    private string $token;

    /**
     * 获取实例
     * @return null|static
     */
    public static function getInstance(): null|static
    {
        $name = get_called_class();
        if (!isset(self::$_instance[$name])) {
            self::$_instance[$name] = new static();
        }

        return self::$_instance[$name];
    }

    /**
     * 获取 Token
     * @return $this|null
     * @throws Exception
     */
    public function getToken(): null|static
    {
        $token = request()->bearerToken();
        if (empty($token)) return UtilsService::getInstance()->notAuth('请先登录');
        $this->token = $token;
        return $this;
    }

    /**
     * 生成 JWT Token
     * @param array $data 要嵌入到 token 中的数据
     * @return string
     */
    public function generateToken(array $data): string
    {
        $issuedAt = time();
        $expirationTime = $issuedAt + config('cc.redis.jwt_ttl', 600000);

        $payload = [
            'iat' => $issuedAt,
            'exp' => $expirationTime,
            'data' => $data
        ];
        RedisService::getInstance()->init(config('cc.redis.jwt'))->set($data['id'], json_encode($data));
        return JWT::encode($payload, $this->secretKey, 'HS256');
    }

    /**
     * 解析 JWT Token
     * @return object|null 返回解码后的 payload 或者 null 如果验证失败
     * @throws Exception
     */
    public function parseToken(): ?object
    {
        try {
            if (empty($this->token)) return UtilsService::getInstance()->notAuth('请先登录');
            return JWT::decode($this->token, new Key($this->secretKey, 'HS256'));
        } catch (Exception $e) {
            return UtilsService::getInstance()->notAuth('【1】Token解析失败！请重新登录：'. $e->getMessage());
        }
    }


    /**
     * 解析 JWT Token
     * @return array|null 返回解码后的 payload 或者 null 如果验证失败
     * @throws Exception
     */
    public function getUserInfo(): ?array
    {
        try {
            $jwt = $this->parseToken();
            $user = RedisService::getInstance()->init(config('cc.redis.jwt'))->get($jwt->data->id);
            if (empty($user)) return UtilsService::getInstance()->notAuth('登录状态过期');
            return json_decode($user, true);
        } catch (Exception $e) {
            return UtilsService::getInstance()->notAuth('【2】Token解析失败！请重新登录：'. $e->getMessage());
        }
    }

    /**
     * 续签 JWT Token
     * @return string|null 新的 JWT 字符串或者 null 如果原 token 已过期或无效
     * @throws Exception
     */
    public function refreshToken(): ?string
    {
        $decoded = $this->parseToken();
        if ($decoded === null || !property_exists($decoded, 'data')) {
            return null;
        }

        return $this->generateToken((array)$decoded->data);
    }
}