<?php
// SPDX-License-Identifier: GPL-3.0-or-later
declare(strict_types=1);

namespace Aiwend\Support;

/**
 * Supported-environment statement (ADR-00): what Aiwend requires, and what has actually been verified.
 * Used for the admin readiness notice, the Diagnostics screen and the health endpoint. It never blocks the site.
 *
 * The declared minimums are a policy backed by tests; the VERIFIED series are the release series that were really exercised (unit suite with
 * every real-database variant, the integration suite and an install/uninstall run). A server at or above the minimum is supported; its exact
 * patch version never matters, and a series that was simply not exercised is "unverified", which is information, not a defect.
 */
final class Compatibility
{
    public const MIN_PHP = '8.2';
    public const MIN_WP = '7.0';
    public const MIN_MYSQL = '8.0';
    public const MIN_MARIADB = '10.11';
    /** Release series actually exercised (MySQL 8.0 and 8.4, MariaDB 10.11 and 11.4). Patch versions within them are covered. */
    public const VERIFIED_SERIES = ['MySQL' => ['8.0', '8.4'], 'MariaDB' => ['10.11', '11.4']];

    /**
     * Classifies a database server version string as returned by the server
     * (e.g. "8.4.11", "11.4.13-MariaDB", "5.5.5-10.11.6-MariaDB").
     *
     * @return array{engine:string, version:string, status:'verified'|'unverified'|'unsupported'|'unknown'}
     *   verified: same major.minor series as an exercised server (any patch version); unverified: at or above the minimum but a series that
     *   was not exercised (for example a newer release); unsupported: below the minimum; unknown: the version string could not be read
     */
    public static function database(string $serverVersion): array
    {
        $isMaria = stripos($serverVersion, 'mariadb') !== false;
        // MariaDB may report a "5.5.5-" compatibility prefix before its real version.
        $clean = (string) preg_replace('/^5\.5\.5-/', '', $serverVersion);
        if (!preg_match('/^(\d+)\.(\d+)(?:\.(\d+))?/', $clean, $m)) {
            return ['engine' => $isMaria ? 'MariaDB' : 'unknown', 'version' => $serverVersion, 'status' => 'unknown'];
        }
        $version = $m[1] . '.' . $m[2] . (isset($m[3]) ? '.' . $m[3] : '');
        $engine = $isMaria ? 'MariaDB' : 'MySQL';
        $min = $isMaria ? self::MIN_MARIADB : self::MIN_MYSQL;
        $status = match (true) {
            version_compare($m[1] . '.' . $m[2], $min, '<') => 'unsupported',
            in_array($m[1] . '.' . $m[2], self::VERIFIED_SERIES[$engine], true) => 'verified',
            default => 'unverified',
        };
        return ['engine' => $engine, 'version' => $version, 'status' => $status];
    }

    /** True only for a confirmed problem: a server older than the declared minimum. Unverified and unknown servers are not problems. */
    public static function needsAttention(string $status): bool
    {
        return $status === 'unsupported';
    }
}