import fs from 'fs';
import path from 'path';
import matter from 'gray-matter';
import { remark } from 'remark';
import html from 'remark-html';
import chokidar from 'chokidar';

export interface Post {
  slug: string;
  title: string;
  date: string;
  tags: string[];
  summary: string;
  content: string;
  createdAt: Date;
}

const postsDirectory = path.join(process.cwd(), 'posts');

// Function to get file creation date
function getFileCreationDate(filePath: string): Date {
  const stats = fs.statSync(filePath);
  return stats.birthtime;
}

export async function getPostBySlug(slug: string): Promise<Post> {
  const realSlug = slug.replace(/\.md$/, '');
  const fullPath = path.join(postsDirectory, `${realSlug}.md`);
  const fileContents = fs.readFileSync(fullPath, 'utf8');
  const { data, content } = matter(fileContents);
  const createdAt = getFileCreationDate(fullPath);

  const processedContent = await remark()
    .use(html)
    .process(content);

  return {
    slug: realSlug,
    title: data.title,
    date: data.date,
    tags: data.tags || [],
    summary: data.summary,
    content: processedContent.toString(),
    createdAt,
  };
}

export async function getAllPosts(): Promise<Post[]> {
  const fileNames = fs.readdirSync(postsDirectory);
  const allPostsData = await Promise.all(
    fileNames
      .filter((fileName) => fileName.endsWith('.md'))
      .map(async (fileName) => {
        const slug = fileName.replace(/\.md$/, '');
        return getPostBySlug(slug);
      })
  );

  // Sort by creation date (newest first)
  return allPostsData.sort((a, b) => b.createdAt.getTime() - a.createdAt.getTime());
}

export async function getPostsByTag(tag: string): Promise<Post[]> {
  const allPosts = await getAllPosts();
  return allPosts.filter((post) => post.tags.includes(tag));
}
  // File watcher setup
  let watcher: chokidar.FSWatcher | null = null;
  let onChangeCallback: (() => void) | null = null;

  export function watchPosts(callback: () => void) {
    if (watcher) {
    watcher.close();
  }

  onChangeCallback = callback;
  watcher = chokidar.watch(postsDirectory, {
    ignored: /(^|[\/\\])\../, // ignore dotfiles
    persistent: true
  });

  watcher
    .on('add', handleFileChange)
    .on('change', handleFileChange)
    .on('unlink', handleFileChange);
}

function handleFileChange() {
  if (onChangeCallback) {
    onChangeCallback();
  }
}

export function stopWatching() {
  if (watcher) {
    watcher.close();
    watcher = null;
  }
  onChangeCallback = null;
}