export async function runGenerator(
    generatorName: string, options: {[name: string]: any} = {}): Promise<void> {
  const templateName = options['templateName'] || generatorName;

  const env: YeomanEnvironment =
      await (options['env'] || createYeomanEnvironment());

  logger.info(`Running template ${templateName}...`);
  logger.debug(`Running generator ${generatorName}...`);
  const generators = env.getGeneratorsMeta();
  const generator = generators[generatorName];

  if (!generator) {
    logger.error(`Template ${templateName} not found`);
    throw new Error(`Template ${templateName} not found`);
  }

  return new Promise<void>((resolve, reject) => {
    env.run(generatorName, {}, (error: any) => {
      if (error) {
        reject(error);
        return;
      }
      resolve();
    });
  });
}

/**
 * Create the prompt used for selecting which template to run. Generate
 * the list of available generators by filtering relevent ones out from
 * the environment list.
 */
function createSelectPrompt(env: YeomanEnvironment) {
  const generators = env.getGeneratorsMeta();
  const allGeneratorNames = Object.keys(generators).filter((k) => {
    return k.startsWith('polymer-init') && k !== 'polymer-init:app';
  });
  const choices = allGeneratorNames.map((generatorName: string) => {
    const generator = generators[generatorName];
    return getGeneratorDescription(generator, generatorName);
  });

  return {
    message: 'Which starter template would you like to use?',
    choices: choices,
  };
}

/**
 * Create the prompt used for selecting which template to run. Generate
 * the list of available generators by filtering relevent ones out from
 * the environment list.
 */
function createSelectPrompt(env: YeomanEnvironment): InquirerQuestion {
  const generators = env.getGeneratorsMeta();
  const allGeneratorNames = Object.keys(generators).filter((k) => {
    return k.startsWith('polymer-init') && k !== 'polymer-init:app';
  });
  const choices = allGeneratorNames.map((generatorName: string) => {
    const generator = generators[generatorName];
    return getGeneratorDescription(generator, generatorName);
  });

  // Some windows emulators (mingw) don't handle arrows correctly
  // https://github.com/SBoudrias/Inquirer.js/issues/266
  // Fall back to rawlist and use number input
  // Credit to
  // https://gist.github.com/geddski/c42feb364f3c671d22b6390d82b8af8f
  const isMinGW = checkIsMinGW();

  return {
    type: isMinGW ? 'rawlist' : 'list',
    name: 'generatorName',
    message: 'Which starter template would you like to use?',
    choices: choices,
  };
}