import {hsbToRgb, rgbToHsb} from './rgb-hsb'
import {ColorRGB} from './common'


const NEUTRAL_SATURATION_LIST = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
const NEUTRAL_BRIGHTNESS_LIST = [100, 98, 96, 93, 88, 80, 60, 40, 20, 0]
const COLOR_BASE_INDEX = 5

export function rgbNeutralLevel(color: ColorRGB, index: number) {
    const h = Math.round(rgbToHsb(color).h)
    const b = NEUTRAL_BRIGHTNESS_LIST[index]
    const s = h === 0 ? 0 : NEUTRAL_SATURATION_LIST[index]

    return hsbToRgb({h, s, b})
}

function hueLevel(h: number, index: number) {
    const step = 1
    h = Math.round(h)
    h = h - (index - COLOR_BASE_INDEX) * step

    return (360 + h) % 360
}

function saturationLevel(s: number, index: number) {
    s = Math.round(s)
    const step = index < COLOR_BASE_INDEX ? Math.round(s / 5) : 5

    s = s + (index - COLOR_BASE_INDEX) * step

    return s > 100 ? 100 : Math.max(s, 5)
}

function brightnessLevel(b: number, index: number) {
    b = Math.round(b)
    const step = index < COLOR_BASE_INDEX ? -5 : -15

    b = b + (index - COLOR_BASE_INDEX) * step

    return b > 100 ? 100 : Math.max(b, 0)
}

export function rgbLevel(color: ColorRGB, index: number) {
    if (index === COLOR_BASE_INDEX) {
        return color
    }

    const {h, s, b} = rgbToHsb(color)

    return hsbToRgb({
        h: hueLevel(h, index),
        s: saturationLevel(s, index),
        b: brightnessLevel(b, index),
    })
}