import React, { Suspense, lazy, Component, ReactNode } from 'react';
import { Loader2 } from 'lucide-react';
import { logError } from '@/utils/errorLogger';

// ── Error Boundary ──────────────────────────────────────────────────────

interface PluginErrorBoundaryProps {
  children: ReactNode;
  pluginName: string;
}

interface PluginErrorBoundaryState {
  hasError: boolean;
  error: Error | null;
  traceId: string | null;
}

function generateTraceId(): string {
  return 'plugin-err-' + Date.now().toString(36) + '-' + Math.random().toString(36).slice(2, 8);
}

class PluginErrorBoundary extends Component<PluginErrorBoundaryProps, PluginErrorBoundaryState> {
  state: PluginErrorBoundaryState = { hasError: false, error: null, traceId: null };

  static getDerivedStateFromError(error: Error): PluginErrorBoundaryState {
    return { hasError: true, error, traceId: generateTraceId() };
  }

  componentDidCatch(error: Error, errorInfo: React.ErrorInfo): void {
    logError(error, {
      componentStack: errorInfo.componentStack,
      pluginName: this.props.pluginName,
      trace_id: this.state.traceId,
      source: 'PluginErrorBoundary',
    });
  }

  handleRetry = (): void => {
    this.setState({ hasError: false, error: null, traceId: null });
  };

  render() {
    if (this.state.hasError) {
      return (
        <div
          className="flex flex-col items-center justify-center min-h-[300px] p-8 text-center"
          role="alert"
          aria-live="assertive"
        >
          <div className="text-danger-500 text-4xl mb-3" aria-hidden="true">⚠️</div>
          <h2 className="text-lg font-bold text-secondary-900 mb-2">
            Plugin konnte nicht geladen werden
          </h2>
          <p className="text-sm text-secondary-600 mb-3">
            Das Plugin „{this.props.pluginName}" hat einen Fehler verursacht.
          </p>
          {this.state.traceId && (
            <p className="text-xs text-secondary-400 mb-3 font-mono" data-testid="plugin-error-trace-id">
              Trace-ID: {this.state.traceId}
            </p>
          )}
          {this.state.error && (
            <details className="mb-4 max-w-lg text-left text-secondary-500">
              <summary className="cursor-pointer text-sm hover:text-secondary-700">
                Fehlerdetails
              </summary>
              <pre className="mt-2 p-3 bg-secondary-50 rounded text-xs overflow-auto max-h-32">
                {this.state.error.message}
                {this.state.error.stack ? `\n\n${this.state.error.stack}` : ''}
              </pre>
            </details>
          )}
          <div className="flex gap-3">
            <button
              onClick={this.handleRetry}
              className="inline-flex items-center px-4 py-2 bg-primary-600 text-white text-sm font-medium rounded-md hover:bg-primary-700 focus:outline-none focus-visible:ring-2 focus-visible:ring-primary-500 transition-colors min-h-touch"
            >
              Erneut versuchen
            </button>
            <button
              onClick={() => window.location.reload()}
              className="inline-flex items-center px-4 py-2 bg-secondary-100 text-secondary-700 text-sm font-medium rounded-md hover:bg-secondary-200 focus:outline-none focus-visible:ring-2 focus-visible:ring-secondary-400 transition-colors min-h-touch"
            >
              Neu laden
            </button>
          </div>
        </div>
      );
    }
    return this.props.children;
  }
}

// ── Static Chunk Map (ARCH-019) ─────────────────────────────────────────
//
// Vite cannot statically analyze dynamic import paths built at runtime
// (`import(/* @vite-ignore */ path)`), so production builds would fail to
// load plugin pages. All plugin-contributed component paths are known at
// build time — they are declared in the backend manifests — so we register
// them here as explicit lazy imports. Vite chunks each one correctly.
//
// Unknown paths (e.g. third-party plugins added later) fall back to the
// runtime dynamic import, which works in dev mode.

type ComponentModule = Record<string, unknown> & { default?: React.ComponentType<any> };
type LazyComponentFactory = () => Promise<{ default: React.ComponentType<any> }>;

/**
 * Normalize a module namespace to the { default } shape React.lazy expects:
 * uses the default export when present, otherwise the first named export
 * (same fallback as the runtime dynamic-import path below).
 */
function normalizeModule(m: ComponentModule): { default: React.ComponentType<any> } {
  const Comp = (m.default ?? m[Object.keys(m)[0]]) as React.ComponentType<any>;
  return { default: Comp };
}

const STATIC_COMPONENT_MAP: Record<string, LazyComponentFactory> = {
  // Pages
  '@/pages/AgentDashboard': () => import('@/pages/AgentDashboard').then(normalizeModule),
  // BUG (ghost page) fixed in Block I-D: page now exists.
  '@/pages/AIAssistant': () => import('@/pages/AIAssistant').then(normalizeModule),
  '@/pages/AISettings': () => import('@/pages/AISettings').then(normalizeModule),
  '@/pages/AutomationDashboard': () => import('@/pages/AutomationDashboard').then(normalizeModule),
  '@/pages/AutomationSettings': () => import('@/pages/AutomationSettings').then(normalizeModule),
  '@/pages/Calendar': () => import('@/pages/Calendar').then(normalizeModule),
  '@/pages/Communication': () => import('@/pages/Communication').then(normalizeModule),
  '@/pages/Dms': () => import('@/pages/Dms').then(normalizeModule),
  '@/pages/DmsTrash': () => import('@/pages/DmsTrash').then(normalizeModule),
  '@/pages/GlobalSearchResults': () => import('@/pages/GlobalSearchResults').then(normalizeModule),
  '@/pages/ImportExport': () => import('@/pages/ImportExport').then(normalizeModule),
  '@/pages/Mail': () => import('@/pages/Mail').then(normalizeModule),
  '@/pages/MailSettings': () => import('@/pages/MailSettings').then(normalizeModule),
  '@/pages/ProactiveAISettings': () => import('@/pages/ProactiveAISettings').then(normalizeModule),
  '@/pages/Reports': () => import('@/pages/Reports').then(normalizeModule),
  '@/pages/SettingsGroups': () => import('@/pages/SettingsGroups').then(normalizeModule),
  '@/pages/SettingsNotifications': () => import('@/pages/SettingsNotifications').then(normalizeModule),
  '@/pages/SettingsRoles': () => import('@/pages/SettingsRoles').then(normalizeModule),
  '@/pages/SettingsUsers': () => import('@/pages/SettingsUsers').then(normalizeModule),
  '@/pages/Tasks': () => import('@/pages/Tasks').then(normalizeModule),
  '@/pages/Wiki': () => import('@/pages/Wiki').then(normalizeModule),
  '@/pages/Workflows': () => import('@/pages/Workflows').then(normalizeModule),
  // NOTE: The backend manifests also declare contact detail tabs
  // (@/components/contact/Contact*Tab) whose components do not exist in the
  // frontend yet — they are intentionally NOT registered here; they fall
  // through to the runtime fallback and surface via the error boundary.
  // See PROGRESS.md "Ghost components" finding.
};

// ── Lazy Component Cache ────────────────────────────────────────────────

const componentCache = new Map<string, React.LazyExoticComponent<React.ComponentType<any>>>();

function getLazyComponent(componentPath: string): React.LazyExoticComponent<React.ComponentType<any>> {
  if (componentCache.has(componentPath)) {
    return componentCache.get(componentPath)!;
  }

  // Known plugin components: statically chunked at build time (ARCH-019)
  const factory = STATIC_COMPONENT_MAP[componentPath];
  if (factory) {
    const LazyComp = lazy(factory);
    componentCache.set(componentPath, LazyComp);
    return LazyComp;
  }

  // Fallback for unknown paths (third-party plugins): runtime dynamic
  // import. Works in dev; production needs the path registered above.
  const importPath = componentPath.replace(/^@\//, '../../');

  const LazyComp = lazy(() =>
    import(/* @vite-ignore */ importPath).then((m) => ({
      default: m.default || m[Object.keys(m)[0]],
    }))
  );

  componentCache.set(componentPath, LazyComp);
  return LazyComp;
}

// ── PluginPage Component ───────────────────────────────────────────────

interface PluginPageProps {
  component: string;
  pluginName: string;
}

/**
 * PluginPage — dynamically loads a plugin page component using React.lazy().
 * Wraps the lazy component in Suspense with a centered spinner fallback
 * and an ErrorBoundary that shows a fallback message on failure.
 */
export function PluginPage({ component, pluginName }: PluginPageProps) {
  const LazyComp = getLazyComponent(component);

  return (
    <PluginErrorBoundary pluginName={pluginName}>
      <Suspense
        fallback={
          <div className="flex items-center justify-center min-h-[50vh]">
            <Loader2 className="animate-spin h-8 w-8 text-primary-500" />
          </div>
        }
      >
        <LazyComp />
      </Suspense>
    </PluginErrorBoundary>
  );
}