function DillerDao(client) {

  var deviceColumns = 'id, key, created_timestamp';
  var propertyColumns = 'id, device, key, created_timestamp';

  function deviceByKey(key) {
    return client.oneOrNone("SELECT " + deviceColumns + " FROM device WHERE key=$1", key);
  }

  function insertDevice(key) {
    return client.one("INSERT INTO device(id, key, created_timestamp) VALUES(DEFAULT, $1, CURRENT_TIMESTAMP) RETURNING " + deviceColumns, key);
  }

  function devicePropertyByDeviceIdAndKey(deviceId, key) {
    return client.oneOrNone('SELECT id FROM device_property WHERE device=$1 AND key=$2', [deviceId, key]);
  }

  function insertDeviceProperty(deviceId, key) {
    return client.oneOrNone('INSERT INTO device_property(id, device, key, created_timestamp) VALUES(DEFAULT, $1, $2, CURRENT_TIMESTAMP) RETURNING ' + propertyColumns, [deviceId, key]);
  }

  function updatePropertyName(id, name) {
    return client.none('UPDATE device_property SET name=$1 WHERE id=$2', name, id);
  }

  function updatePropertyDescription(id, description) {
    return client.none('UPDATE device_property SET description=$1 WHERE id=$2', description, id);
  }

  function insertValue(propertyId, value) {
    return client.one('INSERT INTO value(property, timestamp, value) VALUES($1, CURRENT_TIMESTAMP, $2) RETURNING timestamp', [propertyId, value]);
  }

  function updateHourAggregatesForProperty(propertyId, timestamp) {
    return client.none('DELETE FROM value_by_hour WHERE property=$1 AND timestamp=DATE_TRUNC(\'hour\', $2::TIMESTAMPTZ)', [propertyId, timestamp])
      .then(function() {
        return client.one('INSERT INTO value_by_hour(property, timestamp, count, max, min, avg) ' +
          'SELECT property, DATE_TRUNC(\'hour\', timestamp) AS timestamp, COUNT(value) AS count, MAX(value::NUMERIC) AS max, MIN(value::NUMERIC) AS min, AVG(value::NUMERIC) AS avg ' +
          'FROM value WHERE property=$1 AND DATE_TRUNC(\'hour\', timestamp)=DATE_TRUNC(\'hour\', $2::TIMESTAMPTZ) ' +
          'GROUP BY property, DATE_TRUNC(\'hour\', timestamp) ' +
          'ORDER BY 2, 1 ' +
          'RETURNING *;', [propertyId, timestamp]);
      });
  }

  function updateMinuteAggregatesForProperty(propertyId, timestamp) {
    return client.none('DELETE FROM value_by_minute WHERE property=$1 AND timestamp=DATE_TRUNC(\'minute\', $2::TIMESTAMPTZ)', [propertyId, timestamp])
      .then(function() {
        return client.one('INSERT INTO value_by_minute(property, timestamp, count, max, min, avg) ' +
          'SELECT property, DATE_TRUNC(\'minute\', timestamp) AS timestamp, COUNT(value) AS count, MAX(value::NUMERIC) AS max, MIN(value::NUMERIC) AS min, AVG(value::NUMERIC) AS avg ' +
          'FROM value ' +
          'WHERE property=$1 AND DATE_TRUNC(\'minute\', timestamp)=DATE_TRUNC(\'minute\', $2::TIMESTAMPTZ) ' +
          'GROUP BY property, DATE_TRUNC(\'minute\', timestamp) ' +
          'ORDER BY 2, 1 ' +
          'RETURNING *;', [propertyId, timestamp]);
      });
  }

  return {
    deviceByKey: deviceByKey,
    insertDevice: insertDevice,

    devicePropertyByDeviceIdAndKey: devicePropertyByDeviceIdAndKey,
    insertDeviceProperty: insertDeviceProperty,
    updatePropertyName: updatePropertyName,
    updatePropertyDescription: updatePropertyDescription,

    insertValue: insertValue,
    updateHourAggregatesForProperty: updateHourAggregatesForProperty,
    updateMinuteAggregatesForProperty: updateMinuteAggregatesForProperty
  }
}

module.exports = DillerDao;