helix/admin/disable-wp-admin.php

<?php
function helix_is_ready(): bool {
    // Ensure the built frontend exists before hijacking admin navigation
    $plugin_base_path = plugin_dir_path(__DIR__); // points to helix/
    $build_js_path = $plugin_base_path . 'build/index.js';
    return file_exists($build_js_path) && is_readable($build_js_path);
}

function helix_normalize_route(string $urlOrPath): string {
    // Convert absolute URLs to a relative admin route
    if (preg_match('#^https?://#i', $urlOrPath)) {
        $parts = wp_parse_url($urlOrPath);
        $path = isset($parts['path']) ? $parts['path'] : '/wp-admin/';
        $query = isset($parts['query']) && $parts['query'] !== '' ? '?' . $parts['query'] : '';
        return $path . $query;
    }

    // Ensure it starts with /wp-admin (allow optional leading slash)
    if (preg_match('#^/?wp-admin#', $urlOrPath)) {
        return str_starts_with($urlOrPath, '/') ? $urlOrPath : '/' . $urlOrPath;
    }

    return '/wp-admin/';
}

function helix_should_hijack_admin(): bool {
    // If user opted into default WP admin, do not hijack
    if (get_option('helix_use_default_admin', false)) {
        return false;
    }
    // If Helix build is unavailable, do not hijack
    if (!helix_is_ready()) {
        return false;
    }
    return true;
}

add_filter('login_redirect', function ($redirect_to, $requested_redirect_to, $user) {
    // Only modify redirect for successful logins
    if (is_wp_error($user)) {
        return $redirect_to;
    }

    // Respect plugin setting to use default WordPress admin or if Helix is not ready
    if (!helix_should_hijack_admin()) {
        return $redirect_to;
    }

    // Determine the intended post-login target
    $intended_target = (is_string($requested_redirect_to) && $requested_redirect_to !== '')
        ? $requested_redirect_to
        : $redirect_to;

    // If the target is not an admin page, do not override
    if ($intended_target && !str_contains($intended_target, 'wp-admin')) {
        return $redirect_to;
    }

    // Default to the dashboard when no target provided
    $helix_route = helix_normalize_route($intended_target ?: '/wp-admin/');

    // Send directly to Helix, preserving the original admin route for the React app
    // Always use '&' because admin.php already has a query string (page=helix)
    return admin_url('admin.php?page=helix&helix_route=' . urlencode($helix_route));
}, 10, 3);

add_action('current_screen', function ($current_screen) {
    // Don't redirect if not in admin
    if (!is_admin()) return;
    
    // Don't redirect AJAX requests
    if (wp_doing_ajax()) return;
    
    // Don't redirect REST API requests
    if (defined('REST_REQUEST') && REST_REQUEST) return;
    
    // Don't redirect cron jobs
    if (defined('DOING_CRON') && DOING_CRON) return;
    
    // Check if we're already on the helix page or wordpress admin page
    if ( in_array( $current_screen->id, array( 'toplevel_page_helix', 'toplevel_page_wordpress-admin' ), true ) ) {
        return;
    }
    
    // Check if user wants to use default WordPress admin
    $use_default_admin = get_option('helix_use_default_admin', false);
    if ($use_default_admin) {
        return;
    }
    
    // Don't redirect if Helix is not ready or the user opted into default admin
    if (!helix_should_hijack_admin()) {
        return;
    }

    // Don't redirect critical WordPress admin functions
    global $pagenow;
    $critical_pages = [
        'admin-ajax.php',
        'admin-post.php',
        'async-upload.php',
        'update.php',
        'update-core.php',
        'upgrade.php',
    ];
    
    if (in_array($pagenow, $critical_pages)) return;
    
    // Capture the current admin URL to pass to Helix for routing
    $current_url = helix_normalize_route($_SERVER['REQUEST_URI']);
    
    // Build the redirect URL with the original path for React routing
    // Always use '&' because admin.php already has a query string (page=helix)
    $redirect_url = admin_url('admin.php?page=helix&helix_route=' . urlencode($current_url));
    
    // Redirect all other admin pages to Helix
    wp_redirect($redirect_url);
    exit;
});