/**
 * Copyright (c) 2017-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
const shell = require('shelljs');

const TRUNCATE_MARKER = /<!--\s*truncate\s*-->/;

function blogPostHasTruncateMarker(content) {
  return TRUNCATE_MARKER.test(content);
}

function extractBlogPostBeforeTruncate(content) {
  return content.split(TRUNCATE_MARKER)[0];
}

function removeExtension(pathStr) {
  return pathStr.replace(/\.[^/.]+$/, '');
}

function getPath(pathStr, cleanUrl = false) {
  if (!pathStr || !cleanUrl || !pathStr.endsWith('.html')) {
    return pathStr;
  }
  return pathStr.endsWith('/index.html')
    ? pathStr.replace(/index\.html$/, '')
    : removeExtension(pathStr);
}

function idx(target, keyPaths) {
  return (
    target &&
    (Array.isArray(keyPaths)
      ? keyPaths.reduce((obj, key) => obj && obj[key], target)
      : target[keyPaths])
  );
}

function isNormalInteger(str) {
  return /^\d+$/.test(str);
}

function getGitLastUpdated(filepath) {
  // To differentiate between content change and file renaming / moving, use --summary
  // To follow the file history until before it is moved (when we create new version), use
  // --follow
  const silentState = shell.config.silent; // save old silent state
  shell.config.silent = true;
  const result = shell
    .exec(`git log --follow --summary --format=%ct ${filepath}`)
    .stdout.trim();
  shell.config.silent = silentState;

  // Format the log results to be ['1234567', 'rename ...', '1234566', 'move ...', '1234565', '1234564']
  const records = result
    .toString('utf-8')
    .replace(/\n\s*\n/g, '\n')
    .split('\n')
    .filter(String);

  const timeSpan = records.find((item, index, arr) => {
    const isTimestamp = isNormalInteger(item);
    const isLastTwoItem = index + 2 >= arr.length;
    const nextItemIsTimestamp = isNormalInteger(arr[index + 1]);
    return isTimestamp && (isLastTwoItem || nextItemIsTimestamp);
  });
  if (timeSpan) {
    const date = new Date(parseInt(timeSpan, 10) * 1000);
    return date.toLocaleString();
  }
  return null;
}

module.exports = {
  blogPostHasTruncateMarker,
  extractBlogPostBeforeTruncate,
  getGitLastUpdated,
  getPath,
  removeExtension,
  idx,
};