<?php

namespace App\Classes;

class JWT
{
    public function __construct(private string $secret = '') {}

    public function create(array $payload): string
    {
        $payload['created_at'] = time();
        $payload['expire_at'] = time() + ($payload['expire_at'] ?? 3600);

        $h = $this->b64(json_encode(['typ'=>'JWT','alg'=>'HS256']));
        $p = $this->b64(json_encode($payload));
        $s = $this->b64(hash_hmac('sha256', "$h.$p",'mobinEshaghi'. $this->secret, true));

        return "$h.$p.$s";
    }

    public function decode(string $jwt): false|array
    {
        [$h,$p,$s] = explode('.', $jwt) + [null,null,null];
        if (!$h || !$p || !$s) return false;

        if (!hash_equals($this->b64(hash_hmac('sha256', "$h.$p", 'mobinEshaghi'.$this->secret, true)), $s)) return false;

        $d = json_decode($this->b64Decode($p), true);
        return isset($d['expire_at']) && ($d['timeLeft']=$d['expire_at']-time())<=0 ? false : $d;
    }

    private function b64(string $data): string { return rtrim(strtr(base64_encode($data), '+/', '-_'), '='); }
    private function b64Decode(string $data): string { return base64_decode(strtr($data, '-_', '+/')); }
}