package cloudwatch

import (
	"github.com/grafana/grafana-plugin-sdk-go/data"
)

func groupResponseFrame(frame *data.Frame, statsGroups []string) (data.Frames, error) {
	var dataFrames data.Frames

	// When a query of the form "stats ... by ..." is made, we want to return
	// one series per group defined in the query, but due to the format
	// the query response is in, there does not seem to be a way to tell
	// by the response alone if/how the results should be grouped.
	// Because of this, if the frontend sees that a "stats ... by ..." query is being made
	// the "statsGroups" parameter is sent along with the query to the backend so that we
	// can correctly group the CloudWatch logs response.
	// Check if we have time field though as it makes sense to split only for time series.
	if hasTimeField(frame) {
		if len(statsGroups) > 0 && len(frame.Fields) > 0 {
			groupedFrames, err := groupResults(frame, statsGroups)
			if err != nil {
				return nil, err
			}

			dataFrames = groupedFrames
		} else {
			setPreferredVisType(frame, "logs")
			dataFrames = data.Frames{frame}
		}
	} else {
		dataFrames = data.Frames{frame}
	}
	return dataFrames, nil
}

func hasTimeField(frame *data.Frame) bool {
	for _, field := range frame.Fields {
		if field.Type() == data.FieldTypeNullableTime {
			return true
		}
	}
	return false
}

func setPreferredVisType(frame *data.Frame, visType data.VisType) {
	if frame.Meta != nil {
		frame.Meta.PreferredVisualization = visType
	} else {
		frame.Meta = &data.FrameMeta{
			PreferredVisualization: visType,
		}
	}
}