/* Credit: https://github.com/hijonathan */

var RESOURCE_URL = 'https://news.google.com',
  BACKUP_FOLDER_ID = '',
  FOLDER_NAME_FORMAT = 'yyyy-MM-dd',
  FILE_NAME_FORMAT = "yyyy-MM-dd'T'HH:00:00",
  // Customize your file extension.
  FILE_EXT = '.html',
  // Folder names are all going to look like this.
  now = new Date(),
  FOLDER_NAME = Utilities.formatDate(now, 'GMT', FOLDER_NAME_FORMAT),
  FILE_NAME = Utilities.formatDate(now, 'GMT', FILE_NAME_FORMAT) + FILE_EXT;

function createBackup() {
  var folder = getFolder(FOLDER_NAME);
  createBackupFile(folder, FILE_NAME, fetchData());
}

// Ensures we're always working within the backup directory.
function getFolder(name) {
  var backupFolder = getBackupFolder(),
    folders = backupFolder.getFoldersByName(name);

  if (folders.hasNext()) {
    folder = folders.next();
  } else {
    folder = backupFolder.createFolder(name);
  }
  return folder;
}

// Returns the root folder where our backups exist.
function getBackupFolder() {
  return DriveApp.getFolderById(BACKUP_FOLDER_ID);
}

function createBackupFile(folder, filename, data, overwrite) {
  if (overwrite) {
    // Technically we're not overwriting here. We're just deleting
    // the duplicates.
    var existingFiles = folder.getFilesByName(filename);
    while (existingFiles.hasNext()) {
      var file = existingFiles.next();
      folder.removeFile(file);
    }
  }
  folder.createFile(filename, data);
}

function fetchData() {
  var exportUrl = RESOURCE_URL;
  return UrlFetchApp.fetch(exportUrl);
}