function getCompletedCertCount(user) {
  return [
    'isApisMicroservicesCert',
    'is2018DataVisCert',
    'isFrontEndLibsCert',
    'isInfosecQaCert',
    'isJsAlgoDataStructCert',
    'isRespWebDesignCert'
  ].reduce((sum, key) => user[key] ? sum + 1 : sum, 0);
}

function getLegacyCertCount(user) {
  return [
    'isFrontEndCert',
    'isBackEndCert',
    'isDataVisCert'
  ].reduce((sum, key) => user[key] ? sum + 1 : sum, 0);
}

export default function populateUser(db, user) {
  return new Promise((resolve, reject) => {
    let populatedUser = {...user};
    db.collection('user')
    .aggregate([
      { $match: { _id: user.id } },
      { $project: { points: { $size: '$progressTimestamps' } } }
    ]).get(function(err, [{ points = 1 } = {}]) {
      if (err) { return reject(err); }
      user.points = points;
      let completedChallengeCount = 0;
      let completedProjectCount = 0;
      if ('completedChallenges' in user) {
        completedChallengeCount = user.completedChallenges.length;
        user.completedChallenges.forEach(item => {
          if (
            'challengeType' in item &&
            (item.challengeType === 3 || item.challengeType === 4)
          ) {
            completedProjectCount++;
          }
        });
      }
      populatedUser.completedChallengeCount = completedChallengeCount;
      populatedUser.completedProjectCount = completedProjectCount;
      populatedUser.completedCertCount = getCompletedCertCount(user);
      populatedUser.completedLegacyCertCount = getLegacyCertCount(user);
      populatedUser.completedChallenges = [];
      return resolve(populatedUser);
    });
  });
}