const fs = require('fs');
const path = require('path');
const { promisify } = require('util');
const extract = require('./extract');

// Promisified fs functions
const readdirAsync = promisify(fs.readdir);
const readFileAsync = promisify(fs.readFile);
const writeFileAsync = promisify(fs.writeFile);

// Source and destination paths
const markdownPath = path.resolve(__dirname, '../markdown');
const jsonPath = path.resolve(__dirname, '../../back/public/dist/md-json');

async function writeJson(tuto) {
  // console.log(tuto.title, tuto.slug, tuto.items.map(({ title }) => title));
  const filePath = path.join(jsonPath, `${tuto.slug}.json`);
  const json = JSON.stringify(tuto.items);
  return writeFileAsync(filePath, json);
}

async function writeJsonIndex(tutos) {
  const filePath = path.join(jsonPath, 'index.json');
  const index = tutos.map(({ title, slug }) => ({ title, slug }));
  const json = JSON.stringify(index);
  return writeFileAsync(filePath, json);
}

async function run(filterFunc) {
  const allFiles = await readdirAsync(markdownPath);
  const tutoFiles = allFiles.filter(filterFunc);
  const promises = tutoFiles.map(async tuto => {
    const tutoPath = path.join(markdownPath, tuto);
    const buf = await readFileAsync(tutoPath);
    const md = buf.toString();
    console.log(md.split('\n').shift());
    try {
      return extract(md);
    } catch (err) {
      console.log(err.message);
    }
  });
  const tutos = await Promise.all(promises);
  const writePromises = tutos.map(writeJson);
  writePromises.push(writeJsonIndex(tutos));
  await Promise.all(writePromises);
  process.exit();
}

const filterFunc = f => f.startsWith('tutor');

run(filterFunc);