import { expect, test } from "vitest"

import {
  doSrgbColorValuesMeetContrastRatio,
  isLightSrgbColorValue,
  linearRgbColorValueToRelativeLuminance,
  linearRgbColorValueToTristimulusSum,
  linearRgbColorValueToXyChromaticityValue,
  pickReadableSrgbTextColorValue,
  srgbColorValueToRelativeLuminance,
  srgbColorValueToTristimulusSum,
  srgbColorValueToXyChromaticityValue,
  srgbColorValuesToContrastRatio,
} from "#Source/color/index.ts"

test("linearRgbColorValueToRelativeLuminance follows the explicit RGB branch pipeline", () => {
  expect(linearRgbColorValueToRelativeLuminance({ red: 1, green: 0, blue: 0, alpha: 1 })).toBe(
    0.212_673,
  )
  expect(linearRgbColorValueToRelativeLuminance({ red: 1, green: 1, blue: 1, alpha: 1 })).toBe(1)
})

test("srgbColorValueToRelativeLuminance follows the explicit RGB branch pipeline", () => {
  expect(srgbColorValueToRelativeLuminance({ red: 51, green: 102, blue: 153, alpha: 1 })).toBe(
    0.125_053,
  )
  expect(srgbColorValueToRelativeLuminance({ red: 255, green: 255, blue: 255, alpha: 1 })).toBe(1)
})

test("srgbColorValuesToContrastRatio supports accessibility-oriented comparisons", () => {
  expect(
    srgbColorValuesToContrastRatio(
      { red: 0, green: 0, blue: 0, alpha: 1 },
      { red: 255, green: 255, blue: 255, alpha: 1 },
    ),
  ).toBe(21)

  expect(
    srgbColorValuesToContrastRatio(
      { red: 51, green: 102, blue: 153, alpha: 1 },
      { red: 51, green: 102, blue: 153, alpha: 1 },
    ),
  ).toBe(1)
})

test("doSrgbColorValuesMeetContrastRatio validates thresholds and comparisons", () => {
  expect(() =>
    doSrgbColorValuesMeetContrastRatio(
      { red: 0, green: 0, blue: 0, alpha: 1 },
      { red: 255, green: 255, blue: 255, alpha: 1 },
      0.99,
    ),
  ).toThrow(RangeError)

  expect(
    doSrgbColorValuesMeetContrastRatio(
      { red: 0, green: 0, blue: 0, alpha: 1 },
      { red: 255, green: 255, blue: 255, alpha: 1 },
      7,
    ),
  ).toBe(true)

  expect(
    doSrgbColorValuesMeetContrastRatio(
      { red: 120, green: 120, blue: 120, alpha: 1 },
      { red: 255, green: 255, blue: 255, alpha: 1 },
      4.5,
    ),
  ).toBe(false)
})

test("pickReadableSrgbTextColorValue chooses the more readable candidate", () => {
  expect(pickReadableSrgbTextColorValue({ red: 0, green: 102, blue: 204, alpha: 1 })).toEqual({
    red: 255,
    green: 255,
    blue: 255,
    alpha: 1,
  })

  expect(
    pickReadableSrgbTextColorValue(
      { red: 250, green: 240, blue: 210, alpha: 1 },
      {
        darkColor: { red: 32, green: 32, blue: 32, alpha: 1 },
        lightColor: { red: 255, green: 255, blue: 255, alpha: 1 },
      },
    ),
  ).toEqual({
    red: 32,
    green: 32,
    blue: 32,
    alpha: 1,
  })
})

test("linearRgbColorValueToTristimulusSum follows the explicit RGB branch pipeline", () => {
  expect(linearRgbColorValueToTristimulusSum({ red: 1, green: 0, blue: 0, alpha: 1 })).toBe(
    0.644_463,
  )
  expect(linearRgbColorValueToTristimulusSum({ red: 1, green: 1, blue: 1, alpha: 1 })).toBe(3.039_3)
})

test("srgbColorValueToTristimulusSum follows the explicit RGB branch pipeline", () => {
  expect(srgbColorValueToTristimulusSum({ red: 51, green: 102, blue: 153, alpha: 1 })).toBe(
    0.562_889,
  )
  expect(srgbColorValueToTristimulusSum({ red: 255, green: 255, blue: 255, alpha: 1 })).toBe(
    3.039_3,
  )
})

test("linearRgbColorValueToXyChromaticityValue follows the explicit RGB branch pipeline", () => {
  expect(linearRgbColorValueToXyChromaticityValue({ red: 1, green: 0, blue: 0, alpha: 1 })).toEqual(
    {
      x: 0.64,
      y: 0.33,
    },
  )
})

test("srgbColorValueToXyChromaticityValue follows the explicit RGB branch pipeline", () => {
  expect(srgbColorValueToXyChromaticityValue({ red: 51, green: 102, blue: 153, alpha: 1 })).toEqual(
    {
      x: 0.210_775,
      y: 0.222_163,
    },
  )
})

test("isLightSrgbColorValue uses relative luminance threshold", () => {
  expect(isLightSrgbColorValue({ red: 255, green: 255, blue: 255, alpha: 1 })).toBe(true)
  expect(isLightSrgbColorValue({ red: 0, green: 0, blue: 0, alpha: 1 })).toBe(false)
  expect(isLightSrgbColorValue({ red: 128, green: 128, blue: 128, alpha: 1 }, 0.2)).toBe(true)

  expect(() => isLightSrgbColorValue({ red: 128, green: 128, blue: 128, alpha: 1 }, 1.1)).toThrow(
    RangeError,
  )
})