import { expect, test } from "bun:test";
import { sweepInterval } from "./sweep1d.ts";

test("moving right into the interval", () => {
	// point at 0, moves +10 this frame, interval [5, 8]
	// enters at (5-0)/10 = 0.5, exits at (8-0)/10 = 0.8
	const s = sweepInterval(0, 10, 5, 8)!;
	expect(s.entry).toBeCloseTo(0.5);
	expect(s.exit).toBeCloseTo(0.8);
});

test("moving left: entry/exit are swapped into order", () => {
	// point at 10, moves -10, interval [5, 8]
	// crosses 8 at t=0.2, crosses 5 at t=0.5 -> entry 0.2, exit 0.5
	const s = sweepInterval(10, -10, 5, 8)!;
	expect(s.entry).toBeCloseTo(0.2);
	expect(s.exit).toBeCloseTo(0.5);
	expect(s.entry).toBeLessThanOrEqual(s.exit);
});

test("not moving but already inside -> infinite span", () => {
	const s = sweepInterval(6, 0, 5, 8)!;
	expect(s.entry).toBe(-Infinity);
	expect(s.exit).toBe(Infinity);
});

test("not moving and outside -> null", () => {
	expect(sweepInterval(2, 0, 5, 8)).toBeNull();
});