/**
 * Generates changelog data file for the frontend.
 * Run with: node scripts/generate-changelog-data.js
 */

const fs = require('fs');
const path = require('path');

const CHANGELOG_DIR = path.join(__dirname, '..', 'changelog');
const OUTPUT_FILE = path.join(__dirname, '..', 'src', 'data', 'changelog-data.ts');

const LANGUAGES = ['en', 'cn', 'de', 'fr'];

function readFile(filePath) {
  try {
    return fs.readFileSync(filePath, 'utf-8');
  } catch {
    return null;
  }
}

function parseMdx(content) {
  const frontmatterMatch = content.match(/^---\n([\s\S]*?)\n---\n([\s\S]*)$/);
  if (!frontmatterMatch) {
    return { title: '', body: content };
  }
  const body = frontmatterMatch[2].trim();
  const frontmatter = frontmatterMatch[1];
  const titleMatch = frontmatter.match(/title:\s*["']?([^"'\n]+)["']?/);
  const title = titleMatch ? titleMatch[1].trim() : '';
  return { title, body };
}

// Get all unique dates
const dates = [];
const files = fs.readdirSync(CHANGELOG_DIR);
files.forEach(file => {
  const match = file.match(/^(\d{4}-\d{2}-\d{2})-(\w+)\.mdx$/);
  if (match) {
    const date = match[1];
    const lang = match[2];
    if (!dates.includes(date)) {
      dates.push(date);
    }
  }
});

// Sort dates descending
dates.sort((a, b) => new Date(b) - new Date(a));

// Generate data for each language
const data = {};
LANGUAGES.forEach(lang => {
  data[lang] = dates.map(date => {
    const filePath = path.join(CHANGELOG_DIR, `${date}-${lang}.mdx`);
    const content = readFile(filePath);
    if (!content) {
      return null;
    }
    const { title, body } = parseMdx(content);
    return {
      date,
      title,
      lang,
      author: 'ZhenYi',
      body,
    };
  }).filter(Boolean);
});

// Generate TypeScript file
const tsContent = `// Auto-generated from changelog/*.mdx files
// Run: node scripts/generate-changelog-data.js

export type ChangelogEntry = {
  date: string;
  title: string;
  lang: string;
  author: string;
  body: string;
};

export const CHANGELOG_DATA: Record<string, ChangelogEntry[]> = ${JSON.stringify(data, null, 2)};

export const CHANGELOG_LANGUAGES = ${JSON.stringify(LANGUAGES)};
`;

fs.writeFileSync(OUTPUT_FILE, tsContent);
console.log(`Generated ${OUTPUT_FILE}`);