package eval

import (
	"fmt"
	"strings"

	"github.com/grafana/grafana-plugin-sdk-go/data"
	"github.com/grafana/grafana/pkg/expr/classic"
)

func extractEvalString(frame *data.Frame) (s string) {
	if frame == nil {
		return "empty frame"
	}

	if frame.Meta == nil || frame.Meta.Custom == nil {
		return
	}

	if evalMatches, ok := frame.Meta.Custom.([]classic.EvalMatch); ok {
		sb := strings.Builder{}

		for i, m := range evalMatches {
			sb.WriteString("[ ")
			sb.WriteString(fmt.Sprintf("metric='%s' ", m.Metric))
			sb.WriteString(fmt.Sprintf("labels={%s} ", m.Labels))

			valString := "null"
			if m.Value != nil {
				valString = fmt.Sprintf("%v", *m.Value)
			}

			sb.WriteString(fmt.Sprintf("value=%v ", valString))

			sb.WriteString("]")
			if i < len(evalMatches)-1 {
				sb.WriteString(", ")
			}
		}
		return sb.String()
	}

	if caps, ok := frame.Meta.Custom.([]NumberValueCapture); ok {
		sb := strings.Builder{}

		for i, c := range caps {
			sb.WriteString("[ ")
			sb.WriteString(fmt.Sprintf("var='%s' ", c.Var))
			sb.WriteString(fmt.Sprintf("labels={%s} ", c.Labels))

			valString := "null"
			if c.Value != nil {
				valString = fmt.Sprintf("%v", *c.Value)
			}

			sb.WriteString(fmt.Sprintf("value=%v ", valString))

			sb.WriteString("]")
			if i < len(caps)-1 {
				sb.WriteString(", ")
			}
		}
		return sb.String()
	}

	return ""
}

// extractValues returns the RefID and value for all reduce and math expressions
// in the frame. It does not return values for classic conditions as the values
// in classic conditions do not have a RefID. It returns nil if there are
// no results in the frame.
func extractValues(frame *data.Frame) map[string]NumberValueCapture {
	if frame == nil {
		return nil
	}
	if frame.Meta == nil || frame.Meta.Custom == nil {
		return nil
	}
	if caps, ok := frame.Meta.Custom.([]NumberValueCapture); ok {
		v := make(map[string]NumberValueCapture, len(caps))
		for _, c := range caps {
			v[c.Var] = c
		}
		return v
	}
	return nil
}