import { describe, expect, it } from 'vitest';
import { closestOnSegment, dot } from '../../src/core/util/vec';

describe('closestOnSegment', () => {
  const a = { x: 0, y: 0 };
  const b = { x: 10, y: 0 };

  it('drops the point onto the segment', () => {
    expect(closestOnSegment({ x: 4, y: 7 }, a, b)).toEqual({ x: 4, y: 0 });
  });

  it('stops at the ends instead of running along the line', () => {
    expect(closestOnSegment({ x: -5, y: 3 }, a, b)).toEqual(a);
    expect(closestOnSegment({ x: 25, y: 3 }, a, b)).toEqual(b);
  });

  it('takes a segment of no length as its one point', () => {
    expect(closestOnSegment({ x: 3, y: 4 }, b, b)).toEqual(b);
  });
});

describe('dot', () => {
  it('is zero for perpendicular vectors', () => {
    expect(dot({ x: 2, y: 3 }, { x: -3, y: 2 })).toBe(0);
  });
});