import { lazy, type ComponentType, type LazyExoticComponent } from 'react';

export interface AdminPageEntry {
  file: string;
  exportName: string;
  devImport: () => Promise<Record<string, ComponentType>>;
}

function readPluginUrlFromGlobals(): string {
  const w = window;
  return (
    w.llmagnetDashboardData?.pluginUrl ||
    w.llmagnetPagesData?.pluginUrl ||
    w.llmagnetBotAnalyticsData?.pluginUrl ||
    w.llmagnetProductsData?.pluginUrl ||
    w.llmagnetReportsData?.pluginUrl ||
    w.llmagnetContentSettingsData?.pluginUrl ||
    w.llmagnetSchemaData?.pluginUrl ||
    w.llmagnetAgentReadyData?.pluginUrl ||
    w.llmagnetUcpData?.pluginUrl ||
    w.llmagnetConnectionsData?.pluginUrl ||
    w.llmagnetMcpData?.pluginUrl ||
    w.llmagnetSystemInfoData?.pluginUrl ||
    ''
  );
}

/**
 * Resolve the direct plugin URL base for lazy-loaded page bundles.
 *
 * Elementor Cloud serves enqueued scripts via index.php?dynamic_asset=… which
 * makes import.meta.url point at /wp-admin/ and breaks Vite relative imports.
 */
export function resolveAssetsBaseUrl(): string {
  const shell = window.llmagnetAdminShell;
  if (shell?.assetsBaseUrl) {
    return shell.assetsBaseUrl;
  }

  const script = document.getElementById('llmagnet-admin-shell-js') as HTMLScriptElement | null;
  if (script?.src) {
    const dynamic = script.src.match(/[?&]dynamic_asset=([^&]+)/);
    if (dynamic) {
      const asset_path = decodeURIComponent(dynamic[1]).replace(/^\/+/, '');
      const js_marker = 'assets/react-build/js/';
      const marker_at = asset_path.indexOf(js_marker);
      if (marker_at !== -1) {
        const prefix = asset_path.slice(0, marker_at + js_marker.length);
        try {
          return new URL(prefix, script.src).href;
        } catch {
          // fall through
        }
      }
    }

    const from_script = script.src.replace(/admin-shell\.js(?:\?.*)?$/, '');
    if (from_script !== script.src) {
      return from_script;
    }
  }

  const plugin_url = readPluginUrlFromGlobals();
  if (plugin_url) {
    return `${plugin_url.replace(/\/?$/, '/')}assets/react-build/js/`;
  }

  throw new Error('[LLMagnet] Missing assetsBaseUrl — cannot lazy-load admin page bundle.');
}

function versionQuery(): string {
  const ver = window.llmagnetAdminShell?.version ?? '';
  return ver ? `?ver=${encodeURIComponent(ver)}` : '';
}

/**
 * Build the URL for a lazy-loaded admin page entry bundle.
 */
function adminPageModuleUrl(slug: string, entry: AdminPageEntry): string {
  if (import.meta.env.DEV) {
    return new URL(`./${entry.file}.js`, import.meta.url).href;
  }

  const shell = window.llmagnetAdminShell;
  const from_map = shell?.pageScripts?.[slug];
  if (from_map) {
    return from_map;
  }

  return `${resolveAssetsBaseUrl()}${entry.file}.js${versionQuery()}`;
}

async function loadAdminPageModule(
  slug: string,
  entry: AdminPageEntry,
): Promise<{ default: ComponentType }> {
  if (import.meta.env.DEV) {
    const mod = await entry.devImport();
    return { default: mod[entry.exportName] as ComponentType };
  }

  const url = adminPageModuleUrl(slug, entry);
  const mod = await import(/* @vite-ignore */ url);
  return { default: mod[entry.exportName] as ComponentType };
}

export function lazyAdminPage(
  slug: string,
  entry: AdminPageEntry,
): LazyExoticComponent<ComponentType> {
  return lazy(() => loadAdminPageModule(slug, entry));
}

export function preloadAdminPage(slug: string, entry: AdminPageEntry): Promise<unknown> {
  return loadAdminPageModule(slug, entry);
}

/** Direct URL for shared chunks (stable names from vite.config.ts). */
export function sharedChunkUrl(filename: string): string {
  const name = filename.endsWith('.js') ? filename : `${filename}.js`;
  const shell = window.llmagnetAdminShell;
  const from_map = shell?.sharedChunks?.[name.replace(/\.js$/, '')];
  if (from_map) {
    return from_map;
  }
  return `${resolveAssetsBaseUrl()}${name}${versionQuery()}`;
}