#!/usr/bin/env php
<?php
$configFilename = __DIR__ . '/config.ini';

if (!file_exists($configFilename)) {
  error_log('Failed to read config.ini file. You may copy from config-example.ini and edit it.');
  exit(1);
}

$config = parse_ini_file($configFilename);

// save and load last update id
$getLastUpdateId = fn() => file_exists($config['last_update_id_file']) ? (int)file_get_contents($config['last_update_id_file']) : 0;
$putLastUpdateId = fn($lastUpdateId) => file_put_contents($config['last_update_id_file'], "$lastUpdateId");

// request Telegram Bot API
$requestApi = fn(string $method, ?array $payload = null) => json_decode(file_get_contents(
  "$config[endpoint]$config[token]/$method",
  false,
  stream_context_create(['http' => [
    'method' => 'POST',
    'header' => 'Content-Type: application/json',
    'content' => json_encode($payload),
  ]]),
), true);

// some method we are using
$getMe = fn() => $requestApi('getMe');
$getUpdates = fn(int $offset = 0) => $requestApi('getUpdates', [
  'offset' => $offset,
  'limit' => (int)$config['limit'],
  'timeout' => (int)$config['timeout'],
]);
$sendMessage = fn($params) => $requestApi('sendMessage', $params);

$response = $getMe();
if (!$response['ok']) {
  error_log('Failed to start the bot.');
  error_log("Error message: $response[description]");
  error_log("Error code: $response[error_code]");
  exit(1);
}

$me = $response['result'];
error_log('Login as: ' . json_encode($me, JSON_UNESCAPED_UNICODE));
error_log('Start receiving updates…');
while (($response = $getUpdates($getLastUpdateId() + 1))['ok']) {
  $updates = $response['result'];
  $lastUpdateId = null;
  foreach ($updates as $update) {
    $lastUpdateId = $update['update_id'];

    error_log('Got an update: ' . json_encode($update, JSON_UNESCAPED_UNICODE));
    if (isset($update['message'])) {
      $sendMessage([
        'chat_id' => $update['message']['chat']['id'],
        'text' => '喵',
        'reply_to_message_id' => $update['message']['message_id'],
      ]);
    }

    $putLastUpdateId($lastUpdateId);
  }
}

if (!$response['ok']) {
  error_log('Failed to get updates.');
  error_log("Error message: $response[description]");
  error_log("Error code: $response[error_code]");
  exit(1);
}