<?php
declare(strict_types=1);

namespace Cf7stg;

final class TelegramClient
{
    /**
     * Send a message. Throws TelegramException on error.
     *
     * @param string|int $chat_id
     * @param string     $text        Pre-escaped HTML
     * @param array|null $reply_markup Optional inline_keyboard structure
     */
    public static function send_message($chat_id, string $text, ?array $reply_markup = null): array
    {
        $token = Settings::get_bot_token();
        if ($token === '' || $chat_id === '' || $chat_id === null) {
            throw new TelegramException('Bot token or chat_id not configured', 0, true);
        }

        $body = [
            'chat_id'    => $chat_id,
            'text'       => $text,
            'parse_mode' => 'HTML',
            'disable_web_page_preview' => true,
        ];
        if ($reply_markup !== null) {
            $body['reply_markup'] = wp_json_encode($reply_markup);
        }

        $url = 'https://api.telegram.org/bot' . $token . '/sendMessage';
        $response = wp_remote_post($url, [
            'timeout' => 10,
            'body'    => $body,
        ]);

        if (is_wp_error($response)) {
            throw new TelegramException('Network: ' . $response->get_error_message(), 0, false);
        }

        $code = (int)wp_remote_retrieve_response_code($response);
        $raw = (string)wp_remote_retrieve_body($response);
        $data = json_decode($raw, true);

        if ($code === 200 && is_array($data) && !empty($data['ok'])) {
            return $data;
        }

        $desc = is_array($data) ? (string)($data['description'] ?? '') : '';
        $retry_after = 0;
        if (is_array($data) && isset($data['parameters']['retry_after'])) {
            $retry_after = (int)$data['parameters']['retry_after'];
        }

        $permanent = self::is_permanent($code, $desc);
        throw new TelegramException(
            sprintf('HTTP %d %s', $code, $desc !== '' ? $desc : 'unknown error'),
            $code,
            $permanent,
            $retry_after
        );
    }

    private static function is_permanent(int $code, string $desc): bool
    {
        // 4xx (except 429 rate-limit) are client-side errors: bad request,
        // invalid chat, revoked token, malformed payload — retrying will not
        // help. Mark as permanent so the queue gives up immediately and the
        // admin is notified via the dashboard widget.
        if ($code >= 400 && $code < 500 && $code !== 429) return true;
        return false;
    }
}