import { promises as fs } from 'fs';
import path from 'path';
import marked from 'marked';
import markedOptions from './markedOptions';

marked.setOptions(markedOptions);

interface PostMetadata {
  name: string;
  lastUpdated: string;
}
  
interface Post {
  directory: string;
  path: string;
  meta: PostMetadata;
}

export type {
  PostMetadata,
  Post
};

async function getMetadata(postPath : string) : Promise<PostMetadata> {
  const metaPath = path.join(postPath, 'meta.json');

  const postMetadata = await fs.readFile(metaPath, 'utf8');

  return JSON.parse(postMetadata) as PostMetadata;
}

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

async function getPostFromDirectory(directory : string) {
  const postPath = path.join(POST_PATH, directory);

  const meta = await getMetadata(postPath);

  return {
    directory,
    path: postPath,
    meta
  };
}

async function getPosts() : Promise<Post[]> {
  const directories = await fs.readdir(POST_PATH);

  const posts = await Promise.all(directories.map(getPostFromDirectory));

  return posts.sort((post_a, post_b) => {
    const a = new Date(post_a.meta.lastUpdated);
    const b = new Date(post_b.meta.lastUpdated);

    if(a === b)
      return 0;
    
    if(a > b)
      return -1;
    
    return 1;
  });
}

async function getMarkdown(post : Post) : Promise<string> {
  const markdownPath = path.join(post.path, 'main.md');

  const markdown = await fs.readFile(markdownPath, 'utf8');

  const html = marked(markdown);

  return html;
}

export {
  getPosts,
  getMarkdown,
  getPostFromDirectory
};