<?php

if (!defined('ABSPATH')) {
    exit;
}

// phpcs:disable WordPress.DB.DirectDatabaseQuery -- A backup must read live, uncached data (and take locks); caching would be wrong here.

/**
 * System check shown on the dashboard, in plain language with a suggested fix.
 * Each check: ['label' => ..., 'status' => 'ok'|'warning'|'error', 'message' => ...]
 */
final class SWPB_Preflight
{
    private SWPB_Settings $settings;
    private SWPB_Fs $fs;

    public function __construct(SWPB_Settings $settings, SWPB_Fs $fs)
    {
        $this->settings = $settings;
        $this->fs = $fs;
    }

    public function run(): array
    {
        $checks = [];

        $checks[] = function_exists('gzopen') && function_exists('deflate_init')
            ? $this->ok(__('Compression (zlib)', 'seljebackup'), __('Available.', 'seljebackup'))
            : $this->error(__('Compression (zlib)', 'seljebackup'), __('The PHP zlib extension is missing. Backups cannot be created until your host enables it.', 'seljebackup'));

        $checks[] = SWPB_Crypto::is_available()
            ? $this->ok(__('Encryption for stored passwords', 'seljebackup'), __('Available.', 'seljebackup'))
            : $this->warning(__('Encryption for stored passwords', 'seljebackup'), __('Neither sodium nor OpenSSL is available, so cloud storage credentials cannot be saved. Local backups still work.', 'seljebackup'));

        $dir = $this->fs->base_dir();
        $checks[] = wp_is_writable($dir)
            ? $this->ok(__('Backup folder', 'seljebackup'), sprintf(
                /* translators: %s: folder path */
                __('Writable: %s', 'seljebackup'),
                $dir
            ))
            : $this->error(__('Backup folder', 'seljebackup'), sprintf(
                /* translators: %s: folder path */
                __('Cannot write to %s. Ask your host to fix the folder permissions.', 'seljebackup'),
                $dir
            ));

        $free = $this->fs->free_space($dir);
        $db_size = $this->database_size();
        if ($free === null) {
            $checks[] = $this->ok(__('Free disk space', 'seljebackup'), __('Could not be measured on this host.', 'seljebackup'));
        } elseif ($free < max(200 * MB_IN_BYTES, $db_size * 2)) {
            $checks[] = $this->warning(__('Free disk space', 'seljebackup'), sprintf(
                /* translators: %s: free disk space */
                __('Only %s free. Large backups may fail; consider keeping fewer local backups and using cloud storage.', 'seljebackup'),
                size_format((int)$free)
            ));
        } else {
            $checks[] = $this->ok(__('Free disk space', 'seljebackup'), size_format((int)$free));
        }

        $checks[] = $this->ok(__('Database size', 'seljebackup'), size_format($db_size));

        $limit = (int)ini_get('max_execution_time');
        $checks[] = ($limit > 0 && $limit < 30)
            ? $this->warning(__('PHP time limit', 'seljebackup'), sprintf(
                /* translators: %d: seconds */
                __('%d seconds. Backups still work, but in very small steps.', 'seljebackup'),
                $limit
            ))
            : $this->ok(__('PHP time limit', 'seljebackup'), $limit > 0 ? sprintf(
                /* translators: %d: seconds */
                __('%d seconds (backups run in short steps, so this is fine).', 'seljebackup'),
                $limit
            ) : __('Unlimited.', 'seljebackup'));

        if (defined('DISABLE_WP_CRON') && DISABLE_WP_CRON) {
            $checks[] = $this->warning(__('Scheduled tasks (WP-Cron)', 'seljebackup'), __('WP-Cron is disabled on this site. Make sure a server cron job calls wp-cron.php, or add the Cron URL from the "Remote access" tab to a free cron service.', 'seljebackup'));
        } else {
            $checks[] = $this->ok(__('Scheduled tasks (WP-Cron)', 'seljebackup'), __('Enabled. On low-traffic sites, adding the Cron URL (Remote access tab) to a cron service makes schedules more punctual.', 'seljebackup'));
        }

        if (is_multisite()) {
            $checks[] = $this->warning(__('Multisite', 'seljebackup'), __('Multisite networks are not officially supported yet. The whole network database and files are backed up together.', 'seljebackup'));
        }

        if (!function_exists('ftp_connect')) {
            $checks[] = $this->ok(__('FTP support', 'seljebackup'), __('The PHP FTP extension is not installed, so FTP storage is unavailable. All other storage types work.', 'seljebackup'));
        }

        return $checks;
    }

    public function database_size(): int
    {
        global $wpdb;
        $size = $wpdb->get_var($wpdb->prepare(
            'SELECT SUM(DATA_LENGTH + INDEX_LENGTH) FROM information_schema.TABLES WHERE TABLE_SCHEMA = %s',
            DB_NAME
        ));
        return (int)$size;
    }

    private function ok(string $label, string $message): array
    {
        return ['label' => $label, 'status' => 'ok', 'message' => $message];
    }

    private function warning(string $label, string $message): array
    {
        return ['label' => $label, 'status' => 'warning', 'message' => $message];
    }

    private function error(string $label, string $message): array
    {
        return ['label' => $label, 'status' => 'error', 'message' => $message];
    }
}