/**
 * Docusaurus adapter for the chat widget
 *
 * Provides lifecycle hooks and context detection for Docusaurus sites.
 */

import { initChatWidget } from '../index.js';
import type { ChatWidgetConfig, PageContext, ChatWidgetAPI } from '../index.js';

export type { ChatWidgetConfig, PageContext };

/**
 * Docusaurus-specific configuration (omits getContext since we provide it)
 */
export type DocusaurusConfig = Omit<ChatWidgetConfig, 'getContext'>;

let widget: ChatWidgetAPI | null = null;
let container: HTMLElement | null = null;

/**
 * Initialize the chat widget for Docusaurus
 */
export function initChat(config: DocusaurusConfig): void {
  if (widget) return;

  // Create container
  container = document.createElement('div');
  container.id = 'chat-widget-container';
  document.body.appendChild(container);

  // Initialize widget with Docusaurus context detection
  widget = initChatWidget(container, {
    ...config,
    getContext: getDocusaurusContext,
  });
}

/**
 * Destroy the chat widget
 */
export function destroyChat(): void {
  if (widget) {
    // Properly destroy widget to prevent memory leaks
    widget.destroy();
    widget = null;
  }
  if (container) {
    container.remove();
    container = null;
  }
}

/**
 * Docusaurus lifecycle hook - called on route change
 */
export function onRouteUpdate(): void {
  // Widget persists across route changes
  // Context is re-evaluated on each message send
}

/**
 * Detect page context from Docusaurus URL structure
 *
 * URL patterns:
 * - /{guide}/...                    → guide, latest version
 * - /{guide}/{version}/...          → guide, specific version
 * - /{guide}/next/...               → guide, next version
 */
export function getDocusaurusContext(): PageContext {
  const path = window.location.pathname;
  const segments = path.split('/').filter(Boolean);

  const context: PageContext = {
    site: 'docs',
    currentPage: path,
  };

  if (segments.length === 0) return context;

  // First segment is typically the guide
  context.guide = segments[0];

  // Check if second segment is a version (e.g., "2026.07.01" or "next")
  if (segments.length > 1) {
    const versionPattern = /^\d{4}\.\d{2}\.\d+$|^next$/;
    if (versionPattern.test(segments[1])) {
      context.version = segments[1];
    }
  }

  return context;
}

/**
 * Create a Docusaurus client module export
 *
 * Usage in docusaurus.config.ts:
 * ```ts
 * clientModules: [
 *   require.resolve('@classic-homes/chat-widget/docusaurus')
 * ]
 * ```
 */
export default {
  onRouteUpdate,
};