import { describe, expect, it } from "vitest";
import { hueMatrix, resolveTone, TONES, toneFilters, toneWash } from "./tone.js";

describe("toneFilters", () => {
  it("writes each layer's filter as literal values", () => {
    const filters = toneFilters(TONES.regular.dark);
    expect(filters.body.full).toBe("blur(1.5px) saturate(0.8) contrast(0.53) brightness(0.43)");
    expect(filters.shade.full).toBe("brightness(1.33)");
    expect(filters.glow.full).toBe("saturate(1.1) brightness(1.3)");
    expect(filters.edge.full).toBe("brightness(0.66)");
    expect(filters.highlight.full).toBe("contrast(1.1) brightness(2.4)");
  });

  it("diffuses floating glass more", () => {
    expect(toneFilters(TONES.regular.dark, true).body.full).toBe("blur(6px) saturate(0.8) contrast(0.53) brightness(0.43)");
    expect(toneFilters(TONES.regular.light, true).body.full).toBe("blur(7px) saturate(0.8) contrast(0.3) brightness(1.73)");
  });

  it("drops identity functions and clears the same list", () => {
    const filters = toneFilters(TONES.clear.dark);
    expect(filters.body).toEqual({ full: "blur(1.5px)", clear: "blur(0px)" });
    expect(toneFilters(TONES.clear.light).glow).toEqual({ full: "brightness(1.02)", clear: "brightness(1)" });
  });

  it("leaves a layer unfiltered when every value is identity", () => {
    const tone = { ...TONES.clear.dark, blur: 0 };
    expect(toneFilters(tone).body).toEqual({ full: "none", clear: "none" });
  });
});

describe("resolveTone", () => {
  it("overrides only the given appearance", () => {
    const overrides = { dark: { tint: 0.5 } };
    expect(resolveTone("regular", "dark", overrides).tint).toBe(0.5);
    expect(resolveTone("regular", "light", overrides).tint).toBe(TONES.regular.light.tint);
  });
});

describe("toneWash", () => {
  it("mixes the tint by the tone's share", () => {
    expect(toneWash(TONES.regular.light, "var(--surface)")).toBe("color-mix(in srgb, var(--surface) 40%, transparent)");
    expect(toneWash(TONES.regular.dark, "black")).toBe("color-mix(in srgb, black 50%, transparent)");
    expect(toneWash(TONES.clear.dark, "black")).toBe("transparent");
  });
});

describe("hueMatrix", () => {
  it("leaves neutral colours untinted", () => {
    expect(hueMatrix([128, 128, 128], 1)).toBeNull();
    expect(hueMatrix([255, 255, 255], 1)).toBeNull();
  });

  it("keeps alpha and shifts channels toward the hue", () => {
    const rows = hueMatrix([20, 30, 60], 1)?.split(" ").map(Number) ?? [];
    expect(rows).toHaveLength(20);
    expect(rows.slice(15)).toEqual([0, 0, 0, 1, 0]);
    // Blue gains, red loses: the blue row's own weight rises above red's.
    expect(rows[12]).toBeGreaterThan(rows[0] ?? 0);
  });

  it("scales with strength", () => {
    const full = hueMatrix([20, 30, 60], 1)?.split(" ").map(Number) ?? [];
    const half = hueMatrix([20, 30, 60], 0.5)?.split(" ").map(Number) ?? [];
    expect(Math.abs((half[12] ?? 0) - 1)).toBeCloseTo(Math.abs((full[12] ?? 0) - 1) / 2, 3);
  });
});