import { describe, expect, it } from "vitest";
import {
	DOLLY,
	across,
	parsePath,
	smooth,
	toPath
} from "#lib/components/landing/hackable/dolly.ts";

describe("parsePath", () => {
	it("reads the mark as its four closed contours", () => {
		expect(parsePath(DOLLY)).toHaveLength(4);
	});

	it("closes a contour onto its first anchor rather than doubling it", () => {
		const [contour] = parsePath("M0 0C1 0 2 1 2 2C2 3 1 4 0 4C-1 4 0 1 0 0Z");
		expect(contour).toHaveLength(3);
		expect(contour![0]!.in).toEqual({ x: 0, y: 1 });
	});

	it("keeps straight lines as anchors without handles", () => {
		const [contour] = parsePath("M0 0L4 0L4 4Z");
		expect(contour).toHaveLength(3);
		expect(contour!.every((node) => !node.in && !node.out)).toBe(true);
	});
});

describe("toPath", () => {
	it("round trips the mark", () => {
		const d = toPath(parsePath(DOLLY));
		expect(toPath(parsePath(d))).toBe(d);
		expect(parsePath(d).flat()).toHaveLength(parsePath(DOLLY).flat().length);
	});

	it("writes lines where a segment has no handles", () => {
		expect(toPath(parsePath("M0 0L4 0L4 4Z"))).toBe("M0 0L4 0L4 4L0 0z");
	});
});

describe("smooth", () => {
	it("tells a smooth node from a corner", () => {
		expect(smooth({ x: 0, y: 0, in: { x: -1, y: 0 }, out: { x: 2, y: 0 } })).toBe(true);
		expect(smooth({ x: 0, y: 0, in: { x: -1, y: 0 }, out: { x: 0, y: 2 } })).toBe(false);
		expect(smooth({ x: 0, y: 0, out: { x: 2, y: 0 } })).toBe(false);
	});
});

describe("across", () => {
	it("points straight through the anchor at the given length", () => {
		const p = across({ x: 0, y: 0 }, { x: 3, y: 4 }, 10);
		expect(p.x).toBeCloseTo(-6);
		expect(p.y).toBeCloseTo(-8);
	});
});