import { expect, test } from "vitest";
import { type AABB, vec } from "./given.ts";
import { sweptAABB } from "./swept.ts";

test("box moving right into a wall -> hits at the real gap", () => {
	// A right edge at x=2, B left edge at x=5 -> gap 3, speed 10 -> t=0.3
	const a: AABB = { x: 0, y: 0, w: 2, h: 2 };
	const b: AABB = { x: 5, y: 0, w: 2, h: 2 };
	const hit = sweptAABB(a, vec(10, 0), b)!;
	expect(hit.time).toBeCloseTo(0.3);
	expect(hit.normal).toEqual({ x: -1, y: 0 });
});

test("box passes below the wall -> null", () => {
	const a: AABB = { x: 0, y: 10, w: 2, h: 2 };
	const b: AABB = { x: 5, y: 0, w: 2, h: 2 };
	expect(sweptAABB(a, vec(10, 0), b)).toBeNull();
});

test("box moving left into a wall -> normal points right", () => {
	// A left edge at x=10, B right edge at x=2 -> gap 8, speed 10 -> t=0.8
	const a: AABB = { x: 10, y: 0, w: 2, h: 2 };
	const b: AABB = { x: 0, y: 0, w: 2, h: 2 };
	const hit = sweptAABB(a, vec(-10, 0), b)!;
	expect(hit.time).toBeCloseTo(0.8);
	expect(hit.normal).toEqual({ x: 1, y: 0 });
});

test("diagonal where y blocks first -> horizontal normal", () => {
	const a: AABB = { x: 0, y: 0, w: 2, h: 2 };
	const b: AABB = { x: 5, y: 8, w: 2, h: 2 };
	const hit = sweptAABB(a, vec(10, 10), b)!;
	expect(hit.time).toBeCloseTo(0.6);
	expect(hit.normal).toEqual({ x: 0, y: -1 });
});