import { describe, expect, it } from "vitest";
import { alphaOf, atRuleDeclarations, blend, contrastOf, hexOf, inGamut, oklchOf, tokenSet } from "./css-tokens";

const CSS = `
@theme inline { --color-x: var(--x); }
:root { --x: oklch(0.5 0.1 80); --y: oklch(1 0 0 / 12%); --len: 0.75rem;
  @variant sm { --nested: oklch(0 0 0); } }
.dark { --x: oklch(0.2 0.1 80); --y: oklch(0 0 0); }
:root[data-contrast="sun"] { --x: oklch(0.9 0 0); }
.dark[data-contrast="sun"] { --x: oklch(0.95 0 0); }
`;

describe("css-tokens", () => {
  it("reads oklch values with and without alpha", () => {
    expect(oklchOf("oklch(0.5 0.1 80)")).toEqual([0.5, 0.1, 80]);
    expect(oklchOf("oklch(1 0 0 / 12%)")).toEqual([1, 0, 0]);
    expect(alphaOf("oklch(1 0 0 / 12%)")).toBeCloseTo(0.12);
    expect(alphaOf("oklch(1 0 0)")).toBe(1);
    expect(() => oklchOf("1rem")).toThrow();
  });

  it("converts oklch to an sRGB hex code", () => {
    expect(hexOf([1, 0, 0])).toBe("#ffffff");
    expect(hexOf([0, 0, 0])).toBe("#000000");
    expect(hexOf(oklchOf("oklch(0.968 0.014 85)"))).toBe("#f9f4ea");
  });

  it("contrast of black on white is 21", () => {
    expect(contrastOf([0, 0, 0], [1, 0, 0])).toBeCloseTo(21, 1);
    expect(contrastOf([1, 0, 0], [1, 0, 0])).toBeCloseTo(1, 5);
  });

  it("blends a 15 % tint over its background before measuring", () => {
    const white: [number, number, number] = [1, 0, 0];
    const black: [number, number, number] = [0, 0, 0];
    const mixed = blend(black, 0.15, white);
    expect(mixed[0]).toBeGreaterThan(0.8);
    expect(mixed[0]).toBeLessThan(1);
    expect(contrastOf(mixed, white)).toBeLessThan(contrastOf(black, white));
    expect(blend(black, 1, white)[0]).toBeCloseTo(0, 5);
  });

  it("sun-light layers over light and sun-dark over dark", () => {
    expect(tokenSet(CSS, "light").x).toBe("oklch(0.5 0.1 80)");
    expect(tokenSet(CSS, "dark").x).toBe("oklch(0.2 0.1 80)");
    expect(tokenSet(CSS, "sun-light").x).toBe("oklch(0.9 0 0)");
    expect(tokenSet(CSS, "sun-light").len).toBe("0.75rem");
    expect(tokenSet(CSS, "sun-dark").x).toBe("oklch(0.95 0 0)");
    expect(tokenSet(CSS, "sun-dark").y).toBe("oklch(0 0 0)");
  });

  it("returns only the own declarations of a sun set on request", () => {
    expect(tokenSet(CSS, "sun-light", { own: true })).toEqual({ x: "oklch(0.9 0 0)" });
  });

  it("ignores declarations nested in at-rules", () => {
    expect(tokenSet(CSS, "light").nested).toBeUndefined();
  });

  it("reads the declarations inside an at-rule", () => {
    const css = "@media print { :root, .dark { --a: 1; } .x { --b: 2; } } :root { --c: 3; }";
    expect(atRuleDeclarations(css, "@media print")).toEqual({ a: "1", b: "2" });
  });

  it("detects colours outside the sRGB gamut", () => {
    expect(inGamut([0.6, 0.1, 50])).toBe(true);
    expect(inGamut([0.6, 0.4, 150])).toBe(false);
  });
});