import path from 'path';

import { dest, series } from 'gulp';
import babelify from 'babelify';
import browserify from 'browserify';
import source from 'vinyl-source-stream';
import buffer from 'vinyl-buffer';
import concat from 'gulp-concat';

const PROJECT_DIR = path.join('src', 'newsreader');
const SRC_DIR = path.join(PROJECT_DIR, 'js');
const STATIC_SUFFIX = 'dist/js/';

const CORE_DIR = path.join(PROJECT_DIR, 'news', 'core', 'static', 'core');

const taskMappings = [
  { name: 'homepage', destDir: `${CORE_DIR}/${STATIC_SUFFIX}` },
  { name: 'categories', destDir: `${CORE_DIR}/${STATIC_SUFFIX}` },
];

const babelTask = done => {
  const tasks = taskMappings.map(taskMapping => {
    const { name, destDir } = taskMapping;

    const bundle = browserify({
      entries: `${SRC_DIR}/pages/${name}/index.js`,
      debug: true,
    });

    const transpiledBundle = bundle.transform(babelify);

    return () =>
      transpiledBundle
        .bundle()
        .pipe(source('index.js'))
        .pipe(buffer())
        .pipe(concat(`${name}.js`))
        .pipe(dest(destDir));
  });

  return series(...tasks)(done);
};

export default babelTask;