import { expect, test } from "vitest"

import {
  xyzColorValueToRelativeLuminance,
  xyzColorValueToTristimulusSum,
  xyzColorValueToXyChromaticityValue,
} from "#Source/color/index.ts"

test("xyzColorValueToRelativeLuminance returns y channel", () => {
  expect(xyzColorValueToRelativeLuminance({ x: 0.25, y: 0.3, z: 0.4, alpha: 1 })).toBe(0.3)
  expect(xyzColorValueToRelativeLuminance({ x: 0, y: 0, z: 0, alpha: 1 })).toBe(0)
})

test("xyzColorValueToTristimulusSum returns x plus y plus z", () => {
  expect(xyzColorValueToTristimulusSum({ x: 0.25, y: 0.3, z: 0.4, alpha: 1 })).toBe(0.95)
  expect(xyzColorValueToTristimulusSum({ x: 0, y: 0, z: 0, alpha: 1 })).toBe(0)
})

test("xyzColorValueToXyChromaticityValue returns xy chromaticity coordinates", () => {
  expect(xyzColorValueToXyChromaticityValue({ x: 0.25, y: 0.3, z: 0.4, alpha: 1 })).toEqual({
    x: 0.263_158,
    y: 0.315_789,
  })

  expect(
    xyzColorValueToXyChromaticityValue({ x: 0.412_456, y: 0.212_673, z: 0.019_334, alpha: 1 }),
  ).toEqual({
    x: 0.64,
    y: 0.33,
  })

  expect(() => xyzColorValueToXyChromaticityValue({ x: 0, y: 0, z: 0, alpha: 1 })).toThrow(
    "XYZ tristimulus sum must be greater than 0 to compute xy chromaticity",
  )
})