<?php
namespace A1LocalMdi;

final class Http {
    public static function method(): string {
        return isset($_SERVER['REQUEST_METHOD']) && is_string($_SERVER['REQUEST_METHOD']) ? sanitize_text_field(wp_unslash($_SERVER['REQUEST_METHOD'])) : 'GET';
    }

    /** Require an explicit preference; a browser's wildcard must never switch its format. */
    public static function wants_markdown(string $accept): bool {
        $ranges = [];
        foreach (explode(',', strtolower($accept)) as $item) {
            $parts = array_map('trim', explode(';', $item));
            $type = array_shift($parts);
            $quality = 1.0;
            foreach ($parts as $parameter) {
                if (preg_match('/^q\s*=\s*(.*)$/', $parameter, $match)) {
                    $quality = preg_match('/^(?:0(?:\.\d{0,3})?|1(?:\.0{0,3})?)$/', $match[1]) ? (float) $match[1] : 0.0;
                }
            }
            $ranges[$type] = isset($ranges[$type]) ? max($ranges[$type], $quality) : $quality;
        }
        $markdown = $ranges['text/markdown'] ?? 0.0;
        $html = $ranges['text/html'] ?? $ranges['text/*'] ?? $ranges['*/*'] ?? 0.0;
        return $markdown > 0 && $markdown > $html;
    }

    public static function vary_accept(): void {
        $vary = [];
        foreach (headers_list() as $header) {
            if (stripos($header, 'Vary:') === 0) {
                $vary = array_merge($vary, array_map('trim', explode(',', substr($header, 5))));
            }
        }
        if (!in_array('*', $vary, true) && !in_array('accept', array_map('strtolower', $vary), true)) { $vary[] = 'Accept'; }
        header('Vary: ' . implode(', ', array_unique($vary)));
    }

    public static function has_header(string $name): bool {
        foreach (headers_list() as $header) {
            if (stripos($header, $name . ':') === 0) { return true; }
        }
        return false;
    }

    public static function has_noindex(): bool {
        foreach (headers_list() as $header) {
            if (stripos($header, 'X-Robots-Tag:') === 0 && preg_match('/\b(?:noindex|none)\b/i', substr($header, 13))) { return true; }
        }
        return false;
    }

    public static function no_store(): void {
        // Shared cache-plugin convention; this name must match the cache providers.
        // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedConstantFound
        if (!defined('DONOTCACHEPAGE')) { define('DONOTCACHEPAGE', true); }
        nocache_headers();
        header('Cache-Control: private, no-store, max-age=0');
        foreach (['ETag', 'Last-Modified', 'Content-Length', 'Content-Encoding'] as $name) { header_remove($name); }
    }
}