export const dynamic = "force-dynamic";

import { NextResponse } from 'next/server';
import fs from 'fs';
import path from 'path';
import matter from 'gray-matter';
import { marked } from 'marked';
import DOMPurify from 'dompurify';
import { JSDOM } from 'jsdom';

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

const pinnedPath = path.join(postsDirectory, 'pinned.json');
let pinnedSlugs: string[] = [];
if (fs.existsSync(pinnedPath)) {
  try {
    pinnedSlugs = JSON.parse(fs.readFileSync(pinnedPath, 'utf8'));
  } catch {
    pinnedSlugs = [];
  }
}

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

async function getPostByPath(filePath: string, relPath: string) {
  const fileContents = fs.readFileSync(filePath, 'utf8');
  const { data, content } = matter(fileContents);
  const createdAt = getFileCreationDate(filePath);

  let processedContent = '';
  try {
    marked.setOptions({
      gfm: true,
      breaks: true
    });
    const rawHtml = marked.parse(content);
    const window = new JSDOM('').window;
    const purify = DOMPurify(window);
    processedContent = purify.sanitize(rawHtml as string, {
      ALLOWED_TAGS: [
        'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
        'p', 'a', 'ul', 'ol', 'li', 'blockquote',
        'pre', 'code', 'em', 'strong', 'del',
        'hr', 'br', 'img', 'table', 'thead', 'tbody',
        'tr', 'th', 'td', 'div', 'span', 'iframe'
      ],
      ALLOWED_ATTR: [
        'class', 'id', 'style',
        'href', 'target', 'rel',
        'src', 'alt', 'title', 'width', 'height',
        'frameborder', 'allowfullscreen'
      ],
      ALLOWED_URI_REGEXP: /^(?:(?:(?:f|ht)tps?|mailto|tel|callto|cid|xmpp):|[^a-z]|[a-z+.\-]+(?:[^a-z+.\-:]|$))/i
    });
  } catch (err) {
    console.error(`Error processing markdown for ${relPath}:`, err);
    processedContent = `<div class="error-message">
      <p>Error processing markdown content. Please check the console for details.</p>
      <pre>${err instanceof Error ? err.message : 'Unknown error'}</pre>
    </div>`;
  }

  return {
    type: 'post',
    slug: relPath.replace(/\.md$/, ''),
    title: data.title,
    date: data.date,
    tags: data.tags || [],
    summary: data.summary,
    content: processedContent,
    createdAt: createdAt.toISOString(),
    pinned: pinnedSlugs.includes(relPath.replace(/\.md$/, '')),
  };
}

async function readPostsDir(dir: string, relDir = ''): Promise<any[]> {
  const entries = fs.readdirSync(dir, { withFileTypes: true });
  const folders: any[] = [];
  const posts: any[] = [];

  for (const entry of entries) {
    const fullPath = path.join(dir, entry.name);
    const relPath = relDir ? path.join(relDir, entry.name) : entry.name;

    if (entry.isDirectory()) {
      const children = await readPostsDir(fullPath, relPath);
      folders.push({ type: 'folder', name: entry.name, path: relPath, children });
    } else if (entry.isFile() && entry.name.endsWith('.md')) {
      posts.push(await getPostByPath(fullPath, relPath));
    }
  }

  // Sort posts by creation date (newest first)
  posts.sort((a, b) => new Date(b.createdAt).getTime() - new Date(a.createdAt).getTime());

  // Folders first, then posts
  return [...folders, ...posts];
}

export async function GET() {
  try {
    const tree = await readPostsDir(postsDirectory);
    return NextResponse.json(tree);
  } catch (error) {
    console.error('Error loading posts:', error);
    return NextResponse.json({ error: 'Fehler beim Laden der Beiträge' }, { status: 500 });
  }
}