package perfdata // import nocternity.net/gomonop/pkg/perfdata

import (
	"fmt"
	"strconv"
)

// Performance data range.
type Range struct {
	start  string
	end    string
	inside bool
}

// Creates a performance data range from -inf to 0 and from the specified
// value to +inf.
func RangeMax(max string) *Range {
	if !valueCheck.MatchString(max) {
		panic("invalid performance data range maximum value")
	}
	pdRange := &Range{}
	pdRange.start = "0"
	pdRange.end = max
	return pdRange
}

// Creates a performance data range from -inf to the specified minimal value
// and from the specified maximal value to +inf.
func RangeMinMax(min, max string) *Range {
	if !valueCheck.MatchString(max) {
		panic("invalid performance data range maximum value")
	}
	if !rangeMinCheck.MatchString(min) {
		panic("invalid performance data range minimum value")
	}
	pdRange := &Range{}
	if min == "~" {
		min = ""
	}
	pdRange.start = min
	pdRange.end = max
	return pdRange
}

// Inverts the range.
func (r *Range) Inside() *Range {
	r.inside = true
	return r
}

// Generates the range's string representation so it can be sent to the
// monitoring system.
func (r *Range) String() string {
	var start, inside string

	switch r.start {
	case "":
		start = "~"
	case "0":
		start = ""
	default:
		start = r.start
	}

	if r.inside {
		inside = "@"
	}

	return inside + start + ":" + r.end
}

// Contains checks whether a numeric value is within the range.
func (r *Range) Contains(value float64) bool {
	var inStart, inEnd bool

	if r.start != "" {
		startValue, err := strconv.ParseFloat(r.start, 64)
		if err != nil {
			panic(fmt.Sprintf("invalid performance data range start value: %v", err))
		}
		inStart = value < startValue
	}

	if r.end != "" {
		endValue, err := strconv.ParseFloat(r.end, 64)
		if err != nil {
			panic(fmt.Sprintf("invalid performance data range end value: %v", err))
		}
		inEnd = value > endValue
	}

	return (inStart || inEnd) != r.inside
}