// 1.Flattens messages extracted via the React Intl Babel plugin. An error will be
// thrown if there are messages with the same `id`. The result is a file containing
// `id: message` pairs in "en" locale.
//
// 2. Takes all translations and groups them into a single file.
var fs = require('fs');
var path = require('path');
var globSync = require('glob').sync;
var mkdirpSync = require('mkdirp').sync;

const MESSAGES_PATTERN = './src/i18n/src/**/*.json';
const LANG_DIR         = './src/i18n/';
const LANG_PATTERN     = './src/i18n/*.json';
const FINAL_FILE       = './src/messages.json';

// Read message files generated by react-intl-babel-plugin.
let messages = globSync(MESSAGES_PATTERN)
  .map((filename) => fs.readFileSync(filename, 'utf8'))
  .map((file) => JSON.parse(file))
  .reduce((collection, descriptors) => {
    descriptors.forEach(({id, defaultMessage}) => {
      if (collection.hasOwnProperty(id)) {
          throw new Error(`Duplicate message id: ${id}`);
      }
      collection[id] = defaultMessage;
    });

    return collection;
  }, {});

// Write English translation.
let filename = path.join(LANG_DIR, 'en.json');
mkdirpSync(path.dirname(filename));
fs.writeFileSync(filename, JSON.stringify(messages, null, 2));

// Read all translations.
messages = globSync(LANG_PATTERN)
  .map((filename) => {
    const parts = filename.split('/');
    const locale = parts[parts.length - 1].split('.json')[0];
    return { [locale]: JSON.parse(fs.readFileSync(filename, 'utf8')) };
  })
  .reduce((collection, descriptors) => {
    return { ...collection, ...descriptors };
  }, {});

// Write file with all translations combined.
mkdirpSync(path.dirname(FINAL_FILE));
fs.writeFileSync(FINAL_FILE, JSON.stringify(messages, null, 2));