// EncodeFields converts a map of values with string keys to a byte slice of field
// IDs and values.
//
// If a field exists in the codec, but its type is different, an error is returned. If
// a field is not present in the codec, the system panics.
func (f *FieldCodec) EncodeFields(values map[string]interface{}) ([]byte, error) {
	// Allocate byte slice
	b := make([]byte, 0, 10)

	for k, v := range values {
		field := f.fieldsByName[k]
		if field == nil {
			panic(fmt.Sprintf("field does not exist for %s", k))
		} else if influxql.InspectDataType(v) != field.Type {
			return nil, fmt.Errorf("field \"%s\" is type %T, mapped as type %s", k, k, field.Type)
		}

		var buf []byte

		switch field.Type {
		case influxql.Number:
			var value float64
			// Convert integers to floats.
			if intval, ok := v.(int); ok {
				value = float64(intval)
			} else {
				value = v.(float64)
			}

			buf = make([]byte, 9)
			binary.BigEndian.PutUint64(buf[1:9], math.Float64bits(value))
		case influxql.Boolean:
			value := v.(bool)

			// Only 1 byte need for a boolean.
			buf = make([]byte, 2)
			if value {
				buf[1] = byte(1)
			}
		case influxql.String:
			value := v.(string)
			if len(value) > maxStringLength {
				value = value[:maxStringLength]
			}
			// Make a buffer for field ID (1 bytes), the string length (2 bytes), and the string.
			buf = make([]byte, len(value)+3)

			// Set the string length, then copy the string itself.
			binary.BigEndian.PutUint16(buf[1:3], uint16(len(value)))
			for i, c := range []byte(value) {
				buf[i+3] = byte(c)
			}
		default:
			panic(fmt.Sprintf("unsupported value type: %T", v))
		}

		// Always set the field ID as the leading byte.
		buf[0] = field.ID

		// Append temp buffer to the end.
		b = append(b, buf...)
	}

	return b, nil
}

// Ensure a value's data type can be retrieved.
func TestInspectDataType(t *testing.T) {
	for i, tt := range []struct {
		v   interface{}
		typ influxql.DataType
	}{
		{float64(100), influxql.Float},
	} {
		if typ := influxql.InspectDataType(tt.v); tt.typ != typ {
			t.Errorf("%d. %v (%s): unexpected type: %s", i, tt.v, tt.typ, typ)
			continue
		}
	}
}

// validateSeriesAndFields checks which series and fields are new and whose metadata should be saved and indexed
func (s *Shard) validateSeriesAndFields(points []Point) ([]*SeriesCreate, []*FieldCreate, []string, error) {
	var seriesToCreate []*SeriesCreate
	var fieldsToCreate []*FieldCreate
	var seriesToAddShardTo []string

	// get the mutex for the in memory index, which is shared across shards
	s.index.mu.RLock()
	defer s.index.mu.RUnlock()

	// get the shard mutex for locally defined fields
	s.mu.RLock()
	defer s.mu.RUnlock()

	for _, p := range points {
		// see if the series should be added to the index
		if ss := s.index.series[string(p.Key())]; ss == nil {
			series := NewSeries(string(p.Key()), p.Tags())
			seriesToCreate = append(seriesToCreate, &SeriesCreate{p.Name(), series})
			seriesToAddShardTo = append(seriesToAddShardTo, series.Key)
		} else if !ss.shardIDs[s.id] {
			// this is the first time this series is being written into this shard, persist it
			seriesToCreate = append(seriesToCreate, &SeriesCreate{p.Name(), ss})
			seriesToAddShardTo = append(seriesToAddShardTo, ss.Key)
		}

		// see if the field definitions need to be saved to the shard
		mf := s.measurementFields[p.Name()]
		if mf == nil {
			for name, value := range p.Fields() {
				fieldsToCreate = append(fieldsToCreate, &FieldCreate{p.Name(), &Field{Name: name, Type: influxql.InspectDataType(value)}})
			}
			continue // skip validation since all fields are new
		}

		// validate field types and encode data
		for name, value := range p.Fields() {
			if f := mf.Fields[name]; f != nil {
				// Field present in shard metadata, make sure there is no type conflict.
				if f.Type != influxql.InspectDataType(value) {
					return nil, nil, nil, fmt.Errorf("field type conflict: input field \"%s\" on measurement \"%s\" is type %T, already exists as type %s", name, p.Name(), value, f.Type)
				}

				continue // Field is present, and it's of the same type. Nothing more to do.
			}

			fieldsToCreate = append(fieldsToCreate, &FieldCreate{p.Name(), &Field{Name: name, Type: influxql.InspectDataType(value)}})
		}
	}

	return seriesToCreate, fieldsToCreate, seriesToAddShardTo, nil
}

// MeasurementFields returns a set of fields used across all points.
func (a PointsSlice) MeasurementFields() map[string]*tsdb.MeasurementFields {
	mfs := map[string]*tsdb.MeasurementFields{}
	for _, points := range a {
		for _, p := range points {
			pp := p.Encode()

			// Create measurement field, if not exists.
			mf := mfs[string(pp.Key())]
			if mf == nil {
				mf = &tsdb.MeasurementFields{Fields: make(map[string]*tsdb.Field)}
				mfs[string(pp.Key())] = mf
			}

			// Add all fields on the point.
			for name, value := range p.Fields {
				mf.CreateFieldIfNotExists(name, influxql.InspectDataType(value), false)
			}
		}
	}
	return mfs
}