import fs from 'fs/promises';
import path from 'path';
import axios from 'axios';

const CONTENT_DIR = path.join(process.cwd(), 'content');
const ASSETS_DIR = path.join(process.cwd(), 'public', 'media', 'visual-links');

async function downloadImage(url: string, filename: string): Promise<string> {
  const filepath = path.join(ASSETS_DIR, filename);
  try {
    const response = await axios.get(url, { responseType: 'arraybuffer' });
    await fs.writeFile(filepath, response.data);
    return `/media/visual-links/${filename}`;
  } catch (err: any) {
    console.error(`Failed to download ${url}:`, err.message);
    throw err;
  }
}

async function processMdxFile(filepath: string) {
  let content = await fs.readFile(filepath, 'utf-8');
  let modified = false;

  const linkPreviewRegex = /<Block type="visualLinkPreview" data={([^}]+)}} \/>/g;
  let match;
  let newContent = content;

  // Need to correctly parse the JSON inside data={...}
  // The regex above matches `<Block type="visualLinkPreview" data={{"url":"...","image":"..."}} />`
  // Actually, we can just regex for "image":"https://..."
  const imageRegex = /"image":\s*"([^"]+)"/g;

  while ((match = linkPreviewRegex.exec(content)) !== null) {
    const dataString = match[1] + '}';
    try {
      const data = JSON.parse(dataString);
      if (data.image && data.image.startsWith('http')) {
        const url = new URL(data.image);
        let ext = path.extname(url.pathname);
        if (!ext) ext = '.jpg'; // Fallback
        const filename = `${data.id || Math.random().toString(36).substring(7)}${ext}`;

        console.log(`Downloading ${data.image} to ${filename}...`);
        const newUrl = await downloadImage(data.image, filename);

        const oldImageString = `"image":"${data.image}"`;
        const newImageString = `"image":"${newUrl}"`;
        newContent = newContent.replace(oldImageString, newImageString);
        modified = true;
      }
    } catch (err) {
      console.warn(`Could not parse data string in ${filepath}:`, dataString);
    }
  }

  if (modified) {
    await fs.writeFile(filepath, newContent, 'utf-8');
    console.log(`✅ Updated ${filepath}`);
  }
}

async function walk(dir: string) {
  const files = await fs.readdir(dir);
  for (const file of files) {
    const filepath = path.join(dir, file);
    const stat = await fs.stat(filepath);
    if (stat.isDirectory()) {
      await walk(filepath);
    } else if (file.endsWith('.mdx')) {
      await processMdxFile(filepath);
    }
  }
}

async function main() {
  await fs.mkdir(ASSETS_DIR, { recursive: true });
  await walk(CONTENT_DIR);
}

main().catch(console.error);