/**
 * =============================================================================
 * ERROR BOUNDARY COMPONENT
 * =============================================================================
 *
 * Catches JavaScript errors in child component tree and displays fallback UI.
 *
 * INTERVIEW NOTES:
 * - Error boundaries only catch errors in rendering, lifecycle, and constructors
 * - They do NOT catch: event handlers, async code, SSR, errors in boundary itself
 * - Use componentDidCatch for error logging (e.g., to Sentry)
 * - getDerivedStateFromError updates state to show fallback UI
 */

import { Component, type ReactNode } from 'react';

interface Props {
  children: ReactNode;
  fallback?: ReactNode;
}

interface State {
  hasError: boolean;
  error: Error | null;
}

export default class ErrorBoundary extends Component<Props, State> {
  constructor(props: Props) {
    super(props);
    this.state = { hasError: false, error: null };
  }

  static getDerivedStateFromError(error: Error): State {
    // Update state so next render shows fallback UI
    return { hasError: true, error };
  }

  componentDidCatch(error: Error, errorInfo: React.ErrorInfo): void {
    // Log error to external service (Sentry, LogRocket, etc.)
    console.error('[ErrorBoundary] Caught error:', error);
    console.error('[ErrorBoundary] Error info:', errorInfo);

    // In production, send to error tracking service:
    // Sentry.captureException(error, { extra: errorInfo });
  }

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

  render() {
    if (this.state.hasError) {
      // Custom fallback UI
      if (this.props.fallback) {
        return this.props.fallback;
      }

      // Default fallback UI
      return (
        <div className="min-h-screen flex items-center justify-center p-4">
          <div className="card max-w-lg w-full text-center">
            <div className="w-16 h-16 mx-auto mb-4 rounded-full bg-red-100 dark:bg-red-900 flex items-center justify-center">
              <svg
                className="w-8 h-8 text-red-600 dark:text-red-400"
                fill="none"
                viewBox="0 0 24 24"
                stroke="currentColor"
              >
                <path
                  strokeLinecap="round"
                  strokeLinejoin="round"
                  strokeWidth={2}
                  d="M12 9v2m0 4h.01m-6.938 4h13.856c1.54 0 2.502-1.667 1.732-3L13.732 4c-.77-1.333-2.694-1.333-3.464 0L3.34 16c-.77 1.333.192 3 1.732 3z"
                />
              </svg>
            </div>

            <h2 className="text-xl font-semibold mb-2">Something went wrong</h2>

            <p className="text-gray-600 dark:text-gray-400 mb-4">
              An unexpected error occurred. Please try again.
            </p>

            {import.meta.env.DEV && this.state.error && (
              <details className="text-left mb-4 p-4 bg-gray-100 dark:bg-gray-800 rounded-lg">
                <summary className="cursor-pointer text-sm font-medium text-gray-700 dark:text-gray-300">
                  Error details
                </summary>
                <pre className="mt-2 text-xs text-red-600 dark:text-red-400 overflow-auto">
                  {this.state.error.message}
                  {'\n\n'}
                  {this.state.error.stack}
                </pre>
              </details>
            )}

            <div className="flex gap-4 justify-center">
              <button onClick={this.handleReset} className="btn-primary">
                Try again
              </button>

              <button
                onClick={() => window.location.reload()}
                className="btn-secondary"
              >
                Reload page
              </button>
            </div>
          </div>
        </div>
      );
    }

    return this.props.children;
  }
}