<?php
function telegram_send_text(string $chatId, string $text, string $parseMode = 'HTML'): array {
    global $TELEGRAM_BOT_TOKEN;
    $url = 'https://api.telegram.org/bot'.$TELEGRAM_BOT_TOKEN.'/sendMessage';
    $payload = [
        'chat_id' => $chatId,
        'text' => $text,
        'parse_mode' => $parseMode,
        'disable_web_page_preview' => true,
    ];
    return telegram_post($url, $payload);
}

/**
 * $kind: 'photo' or 'document'
 * - photo → shows as image preview
 * - document → shows as file (any type: pdf/zip/etc.)
 */
function telegram_send_file(string $chatId, string $filePath, string $kind = 'document', ?string $caption = null, string $parseMode = 'HTML'): array {
    global $TELEGRAM_BOT_TOKEN;
    if (!file_exists($filePath)) {
        throw new RuntimeException("File not found: $filePath");
    }

    $method = $kind === 'photo' ? 'sendPhoto' : 'sendDocument';
    $field  = $kind === 'photo' ? 'photo'     : 'document';
    $url = 'https://api.telegram.org/bot'.$TELEGRAM_BOT_TOKEN.'/'.$method;

    $payload = [
        'chat_id' => $chatId,
        $field => new CURLFile(realpath($filePath)),
    ];
    if ($caption !== null) {
        $payload['caption'] = $caption;
        $payload['parse_mode'] = $parseMode;
    }

    return telegram_post($url, $payload, /*multipart=*/true);
}

/* ---- internals ---- */
function telegram_post(string $url, array $payload, bool $multipart = false): array {
    global $TELEGRAM_BOT_TOKEN;
    $ch = curl_init($url);
    curl_setopt_array($ch, [
        CURLOPT_POST => true,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_POSTFIELDS => $payload, // if contains CURLFile, cURL uses multipart automatically
    ]);

    $resp = curl_exec($ch);
    if ($resp === false) {
        $err = curl_error($ch);
        curl_close($ch);
        throw new RuntimeException("cURL error: $err");
    }
    curl_close($ch);

    $data = json_decode($resp, true);
    if (!is_array($data) || empty($data['ok'])) {
        throw new RuntimeException("Telegram error: $resp");
    }
    return $data;
}