package xep0392

import (
    "crypto/sha1"
    "encoding/binary"
    "image"
    "image/color"
    "math"
)

// TODO: import "github.com/hsluv/go-hsluv"
func HsluvToRGB(h, s, l float64) (r, g, b float64) {
    return 0, 0, 0
}

func ColorFromString(id string) color.RGBA {
    hue := hueFromString(id)
    s := 100.0
    l := 50.0
    r, g, b := HsluvToRGB(hue, s, l)
    return color.RGBA{
        R: uint8(clamp01(r) * 255),
        G: uint8(clamp01(g) * 255),
        B: uint8(clamp01(b) * 255),
        A: 255,
    }
}

func ImageWithColor(id string, width, height int) *image.RGBA {
    c := ColorFromString(id)
    img := image.NewRGBA(image.Rect(0, 0, width, height))
    for y := 0; y < height; y++ {
        for x := 0; x < width; x++ {
            img.SetRGBA(x, y, c)
        }
    }
    return img
}

func hueFromString(s string) float64 {
    h := sha1.Sum([]byte(s))
    v := binary.LittleEndian.Uint16(h[18:20])
    hue := float64(v) * 360.0 / 65536.0
    if hue >= 360.0 {
        hue = math.Mod(hue, 360.0)
    }
    return hue
}

func clamp01(f float64) float64 {
    if f < 0 {
        return 0
    }
    if f > 1 {
        return 1
    }
    return f
}