import crypto from 'crypto';
import moment from 'moment';

const makePolicy = () => {
  const policy = {
    conditions: [
      {'bucket': process.env.AWS_S3_UPLOAD_BUCKET_NAME},
      ['starts-with', '$key', ''],
      {'acl': 'public-read'},
      ['content-length-range', 0, process.env.AWS_S3_UPLOAD_MAX_SIZE],
      ['starts-with', '$Content-Type', 'image'],
      ['starts-with', '$Cache-Control', ''],
    ],
    expiration: moment().add(24*60, 'minutes').format('YYYY-MM-DDTHH:mm:ss\\Z'),
  };

  return new Buffer(JSON.stringify(policy)).toString('base64')
};

const signPolicy = (policy) => {
  const signature = crypto.createHmac(
    'sha1',
    process.env.AWS_SECRET_ACCESS_KEY
  ).update(policy).digest('base64');

  return signature;
};

export {
  makePolicy,
  signPolicy,
};