new-server/models/colorvalue.go

package models

import (
	"fmt"
	"math"
	"strconv"
	"strings"
)

type ColorValue struct {
	Hue        float64 `json:"h,omitempty"` // 0..360
	Saturation float64 `json:"s,omitempty"` // 0..=1
	Kelvin     int     `json:"kelvin,omitempty"`
}

func (c *ColorValue) IsHueSat() bool {
	return !c.IsKelvin()
}

func (c *ColorValue) IsKelvin() bool {
	return c.Kelvin > 0
}

func (c *ColorValue) String() string {
	if c.Kelvin > 0 {
		return fmt.Sprintf("k:%d", c.Kelvin)
	}

	return fmt.Sprintf("hs:%g,%g", c.Hue, c.Saturation)
}

func ParseColorValue(raw string) (ColorValue, error) {
	tokens := strings.SplitN(raw, ":", 2)
	if len(tokens) != 2 {
		return ColorValue{}, ErrBadInput
	}

	if tokens[0] == "kelvin" || tokens[0] == "k" {
		parsedPart, err := strconv.Atoi(tokens[1])
		if err != nil {
			return ColorValue{}, ErrBadInput
		}

		return ColorValue{Kelvin: parsedPart}, nil
	}

	if tokens[0] == "hs" {
		parts := strings.Split(tokens[1], ",")
		if len(parts) < 2 {
			return ColorValue{}, ErrUnknownColorFormat
		}

		part1, err1 := strconv.ParseFloat(parts[0], 64)
		part2, err2 := strconv.ParseFloat(parts[1], 64)
		if err1 != nil || err2 != nil {
			return ColorValue{}, ErrBadInput
		}

		return ColorValue{Hue: math.Mod(part1, 360), Saturation: math.Min(math.Max(part2, 0), 1)}, nil
	}

	if tokens[0] == "hsk" {
		parts := strings.Split(tokens[1], ",")
		if len(parts) < 3 {
			return ColorValue{}, ErrUnknownColorFormat
		}

		part1, err1 := strconv.ParseFloat(parts[0], 64)
		part2, err2 := strconv.ParseFloat(parts[1], 64)
		part3, err3 := strconv.Atoi(parts[2])
		if err1 != nil || err2 != nil || err3 != nil {
			return ColorValue{}, ErrBadInput
		}

		return ColorValue{
			Hue:        math.Mod(part1, 360),
			Saturation: math.Min(math.Max(part2, 0), 1),
			Kelvin:     part3,
		}, nil
	}

	return ColorValue{}, ErrUnknownColorFormat
}