import { describe, expect, it } from "vitest";
import { fallbackGray, stepToPx, cellSize } from "./vizConstants";

describe("fallbackGray", () => {
  it("returns lighter gray for step 1", () => {
    const rgb = fallbackGray(1);
    expect(rgb).toBe("rgb(230,230,230)");
  });

  it("returns darker gray for step 12", () => {
    const rgb = fallbackGray(12);
    expect(rgb).toBe("rgb(40,40,40)");
  });

  it("returns mid-gray for step 6", () => {
    const rgb = fallbackGray(6);
    const match = rgb.match(/rgb\((\d+),(\d+),(\d+)\)/);
    expect(match).not.toBeNull();
    const value = Number(match![1]);
    expect(value).toBeGreaterThan(100);
    expect(value).toBeLessThan(200);
  });

  it("produces monotonically decreasing gray values from step 1 to 12", () => {
    const values = Array.from({ length: 12 }, (_, i) => {
      const match = fallbackGray(i + 1).match(/(\d+)/);
      return Number(match![1]);
    });
    for (let i = 1; i < values.length; i++) {
      expect(values[i]).toBeLessThanOrEqual(values[i - 1]);
    }
  });
});

describe("stepToPx", () => {
  it("maps step 1 to half a cell", () => {
    expect(stepToPx(1)).toBe(cellSize / 2);
  });

  it("maps step 2 to 1.5 cells", () => {
    expect(stepToPx(2)).toBe(cellSize + cellSize / 2);
  });

  it("maps step 12 correctly", () => {
    expect(stepToPx(12)).toBe(11 * cellSize + cellSize / 2);
  });

  it("increases by cellSize per step", () => {
    expect(stepToPx(3) - stepToPx(2)).toBe(cellSize);
    expect(stepToPx(7) - stepToPx(6)).toBe(cellSize);
  });
});

describe("cellSize", () => {
  it("is 32", () => {
    expect(cellSize).toBe(32);
  });
});