/* eslint-env node */
/* eslint-disable no-console */
import fs from 'fs';
import { sync as globSync } from 'glob';
import { sync as mkdirpSync } from 'mkdirp';
import chalk from 'chalk';
import prompt from 'prompt';
import localesMap from 'app/i18n';

const MESSAGES_PATTERN = `${__dirname}/../../build/messages/**/*.json`;
const LANG_DIR = `${__dirname}/../app/i18n`;
const DEFAULT_LOCALE = 'en';
const SUPPORTED_LANGS = [DEFAULT_LOCALE, ...Object.keys(localesMap)];

/**
 * Aggregates the default messages that were extracted from the app's
 * React components via the React Intl Babel plugin. An error will be thrown if
 * there are messages in different components that use the same `id`. The result
 * is a flat collection of `id: message` pairs for the app's default locale.
 */
let idToFileMap: { [key: string]: string[] } = {};
let duplicateIds: string[] = [];
const collectedMessages = globSync(MESSAGES_PATTERN)
  .map(filename => [filename, JSON.parse(fs.readFileSync(filename, 'utf8'))])
  .reduce((collection, [file, descriptors]) => {
    descriptors.forEach(({ id, defaultMessage }) => {
      if (collection.hasOwnProperty(id)) {
        duplicateIds.push(id);
      }

      collection[id] = defaultMessage;
      idToFileMap[id] = (idToFileMap[id] || []).concat(file);
    });

    return collection;
  }, {});

if (duplicateIds.length) {
  console.log('\nFound duplicated ids:');
  duplicateIds.forEach(id =>
    console.log(`${chalk.yellow(id)}:\n - ${idToFileMap[id].join('\n - ')}\n`),
  );
  console.log(chalk.red('Please correct the errors above to proceed further!'));

  process.exit(1);
}

duplicateIds = [];
idToFileMap = {};

/**
 * Making a diff with the previous DEFAULT_LOCALE version
 */
const defaultMessagesPath = `${LANG_DIR}/${DEFAULT_LOCALE}.json`;
let keysToUpdate: string[] = [];
let keysToAdd: string[] = [];
let keysToRemove: string[] = [];
const keysToRename: Array<[string, string]> = [];
const isNotMarked = (value: string) => value.slice(0, 2) !== '--';

const prevMessages: { [key: string]: string } = readJSON(defaultMessagesPath);
const prevMessagesMap = Object.entries(prevMessages).reduce(
  (acc, [key, value]) => {
    if (acc[value]) {
      acc[value].push(key);
    } else {
      acc[value] = [key];
    }

    return acc;
  },
  {} as { [key: string]: string[] },
);

keysToAdd = Object.keys(collectedMessages).filter(key => !prevMessages[key]);
keysToRemove = Object.keys(prevMessages)
  .filter(key => !collectedMessages[key])
  .filter(isNotMarked);
keysToUpdate = Object.entries(prevMessages).reduce(
  (acc, [key, message]) =>
    acc.concat(
      collectedMessages[key] && collectedMessages[key] !== message ? key : [],
    ),
  [] as string[],
);

// detect keys to rename, mutating keysToAdd and keysToRemove
[...keysToAdd].forEach(toKey => {
  const keys = prevMessagesMap[collectedMessages[toKey]] || [];
  const fromKey = keys.find(key => keysToRemove.indexOf(key) > -1);

  if (fromKey) {
    keysToRename.push([fromKey, toKey]);

    keysToRemove.splice(keysToRemove.indexOf(fromKey), 1);
    keysToAdd.splice(keysToAdd.indexOf(toKey), 1);
  }
});

if (
  !keysToAdd.length &&
  !keysToRemove.length &&
  !keysToUpdate.length &&
  !keysToRename.length
) {
  console.log(chalk.green('Everything is up to date!'));
  process.exit();
}

console.log(
  chalk.magenta(`The diff relative to default locale (${DEFAULT_LOCALE}) is:`),
);

if (keysToRemove.length) {
  console.log('The following keys will be removed:');
  console.log(
    [chalk.red('\n - '), keysToRemove.join(chalk.red('\n - ')), '\n'].join(''),
  );
}

if (keysToAdd.length) {
  console.log('The following keys will be added:');
  console.log(
    [chalk.green('\n + '), keysToAdd.join(chalk.green('\n + ')), '\n'].join(''),
  );
}

if (keysToUpdate.length) {
  console.log('The following keys will be updated:');
  console.log(
    [
      chalk.yellow('\n @ '),
      keysToUpdate.join(chalk.yellow('\n @ ')),
      '\n',
    ].join(''),
  );
}

if (keysToRename.length) {
  console.log('The following keys will be renamed:\n');
  console.log(
    keysToRename.reduce(
      (str, pair) =>
        [str, pair[0], chalk.yellow(' -> '), pair[1], '\n'].join(''),
      '',
    ),
  );
}

prompt.start();
prompt.get(
  {
    properties: {
      apply: {
        description: 'Apply changes? [Y/n]',
        pattern: /^y|n$/i,
        message: 'Please enter "y" or "n"',
        default: 'y',
        before: value => value.toLowerCase() === 'y',
      },
    },
  },
  (err, resp) => {
    console.log('\n');

    if (err || !resp.apply) {
      return console.log(chalk.red('Aborted'));
    }

    buildLocales();

    console.log(chalk.green('All locales was successfuly built'));
  },
);

function buildLocales() {
  mkdirpSync(LANG_DIR);

  SUPPORTED_LANGS.map(lang => {
    const destPath = `${LANG_DIR}/${lang}.json`;
    const newMessages = readJSON(destPath);

    keysToRename.forEach(([fromKey, toKey]) => {
      newMessages[toKey] = newMessages[fromKey];
      delete newMessages[fromKey];
    });
    keysToRemove.forEach(key => {
      delete newMessages[key];
    });
    keysToUpdate.forEach(key => {
      newMessages[`--${key}`] = newMessages[key];
      newMessages[key] = collectedMessages[key];
    });
    keysToAdd.forEach(key => {
      newMessages[key] = collectedMessages[key];
    });

    const sortedKeys = Object.keys(newMessages).sort((key1, key2) => {
      key1 = key1.replace(/^-+/, '');
      key2 = key2.replace(/^-+/, '');

      return key1 < key2 || !isNotMarked(key1) ? -1 : 1;
    });

    const sortedNewMessages = sortedKeys.reduce((acc, key) => {
      acc[key] = newMessages[key];

      return acc;
    }, {});

    fs.writeFileSync(
      destPath,
      `${JSON.stringify(sortedNewMessages, null, 4)}\n`,
    );
  });
}

function readJSON(destPath) {
  try {
    return JSON.parse(fs.readFileSync(destPath, 'utf8'));
  } catch (err) {
    console.log(
      chalk.yellow(`Can not read ${destPath}. The new file will be created.`),
      `(${err.message})`,
    );
  }

  return {};
}