'use strict';

const { access, rmdir } = require('fs/promises');
const { ncp } = require('ncp');
const { join } = require('path');
const { debuglog, promisify } = require('util');

const internals = {
  ncp: promisify(ncp),
  debuglog: debuglog('blog'),

  kAssetsDirectoryName: 'assets'
};

/**
 * Generates the static assets required for the blog
 *
 * @name StaticGenerator
 * @param {string} source the source directory
 * @param {string} target the target directory
 * @param {Array.<Blog.tPost>} posts the list of posts
 */
module.exports = async function StaticGenerator(source, target, posts) {

  const assetsTarget = join(target, internals.kAssetsDirectoryName);

  internals.debuglog(`Removing ${assetsTarget}`);
  await rmdir(assetsTarget, { recursive: true });

  for (let i = 0; i < posts.length; ++i) {
    const postSourcePath = join(source, `${i}`);

    try {
      await access(postSourcePath);

      const assetsSource = join(postSourcePath, internals.kAssetsDirectoryName);

      internals.debuglog(`Copying ${assetsSource} to ${assetsTarget}`);
      await internals.ncp(assetsSource, assetsTarget);
    }
    catch (error) {
      if (error.code === internals.kFileNotFoundError) {
        internals.debuglog(`Skipping ${i}`);
        continue;
      }

      throw error;
    }
  }
};