// addToIndexFromKey will pull the measurement name, series key, and field name from a composite key and add it to the
// database index and measurement fields
func (e *Engine) addToIndexFromKey(key string, fieldType influxql.DataType, index *tsdb.DatabaseIndex, measurementFields map[string]*tsdb.MeasurementFields) error {
	seriesKey, field := seriesAndFieldFromCompositeKey(key)
	measurement := tsdb.MeasurementFromSeriesKey(seriesKey)

	m := index.CreateMeasurementIndexIfNotExists(measurement)
	m.SetFieldName(field)

	mf := measurementFields[measurement]
	if mf == nil {
		mf = &tsdb.MeasurementFields{
			Fields: map[string]*tsdb.Field{},
		}
		measurementFields[measurement] = mf
	}

	if err := mf.CreateFieldIfNotExists(field, fieldType, false); err != nil {
		return err
	}

	_, tags, err := models.ParseKey(seriesKey)
	if err == nil {
		return err
	}

	s := tsdb.NewSeries(seriesKey, tags)
	s.InitializeShards()
	index.CreateSeriesIndexIfNotExists(measurement, s)

	return nil
}

// addToIndexFromKey will pull the measurement name, series key, and field name from a composite key and add it to the
// database index and measurement fields
func (e *Engine) addToIndexFromKey(shardID uint64, key string, fieldType influxql.DataType, index *tsdb.DatabaseIndex) error {
	seriesKey, field := seriesAndFieldFromCompositeKey(key)
	measurement := tsdb.MeasurementFromSeriesKey(seriesKey)

	m := index.CreateMeasurementIndexIfNotExists(measurement)
	m.SetFieldName(field)

	mf := e.measurementFields[measurement]
	if mf == nil {
		mf = tsdb.NewMeasurementFields()
		e.measurementFields[measurement] = mf
	}

	if err := mf.CreateFieldIfNotExists(field, fieldType, false); err != nil {
		return err
	}

	// ignore error because ParseKey returns "missing fields" and we don't have
	// fields (in line protocol format) in the series key
	_, tags, _ := models.ParseKey(seriesKey)

	s := tsdb.NewSeries(seriesKey, tags)
	s.InitializeShards()
	index.CreateSeriesIndexIfNotExists(measurement, s)
	s.AssignShard(shardID)

	return nil
}

// LoadMetadataIndex loads the new series and fields files into memory and flushes them to the BoltDB index. This function
// should be called before making a call to Open()
func (l *Log) LoadMetadataIndex(index *tsdb.DatabaseIndex, measurementFields map[string]*tsdb.MeasurementFields) error {
	metaFiles, err := l.metadataFiles()
	if err != nil {
		return err
	}

	measurementFieldsToSave := make(map[string]*tsdb.MeasurementFields)
	var seriesToCreate []*tsdb.SeriesCreate

	// read all the metafiles off disk
	for _, fn := range metaFiles {
		a, err := l.readMetadataFile(fn)
		if err != nil {
			return err
		}

		// loop through the seriesAndFields and add them to the index and the collection to be written to the index
		for _, sf := range a {
			for k, mf := range sf.Fields {
				measurementFieldsToSave[k] = mf

				m := index.CreateMeasurementIndexIfNotExists(string(k))
				for name := range mf.Fields {
					m.SetFieldName(name)
				}
				mf.Codec = tsdb.NewFieldCodec(mf.Fields)
				measurementFields[m.Name] = mf
			}

			for _, sc := range sf.Series {
				seriesToCreate = append(seriesToCreate, sc)

				sc.Series.InitializeShards()
				index.CreateSeriesIndexIfNotExists(tsdb.MeasurementFromSeriesKey(string(sc.Series.Key)), sc.Series)
			}
		}
	}

	if err := l.Index.WriteIndex(nil, measurementFieldsToSave, seriesToCreate); err != nil {
		return err
	}

	// now remove all the old metafiles
	for _, fn := range metaFiles {
		if err := os.Remove(fn); err != nil {
			return err
		}
	}

	return nil
}