<?php

declare(strict_types=1);

namespace app\miniapi\auth;

use app\miniapi\exception\ApiException;

/** Atomic, bounded, shared by workers on one host. Use a shared limiter before scaling to multiple hosts. */
final class LoginThrottle
{
    public function consume(string $ip): void
    {
        $path = (string) config('mini_api.login_throttle_file', runtime_path('mini-login-rate.json'));
        $file = @fopen($path, 'c+');
        if (!$file) {
            throw new ApiException(50302, '登录服务暂时不可用', 503);
        }
        try {
            if (!flock($file, LOCK_EX)) {
                throw new ApiException(50302, '登录服务暂时不可用', 503);
            }
            $window = intdiv(time(), 60);
            $state = json_decode(stream_get_contents($file), true);
            if (!is_array($state) || ($state['window'] ?? null) !== $window) {
                $state = [
                    'window' => $window,
                    'total' => 0,
                    'clients' => [],
                ];
            }
            $key = hash('sha256', $ip);
            if ($state['total'] >= (int) config('mini_api.login_global_per_minute', 600)
                || ($state['clients'][$key] ?? 0) >= (int) config('mini_api.login_ip_per_minute', 60)
                || (!isset($state['clients'][$key]) && count($state['clients']) >= 4096)) {
                throw new ApiException(42901, '登录请求过于频繁，请稍后再试', 429);
            }
            $state['total']++;
            $state['clients'][$key] = ($state['clients'][$key] ?? 0) + 1;
            $json = json_encode($state, JSON_THROW_ON_ERROR);
            rewind($file);
            if (!ftruncate($file, 0) || fwrite($file, $json) !== strlen($json) || !fflush($file)) {
                throw new ApiException(50302, '登录服务暂时不可用', 503);
            }
        } finally {
            flock($file, LOCK_UN);
            fclose($file);
        }
    }
}