import { describe, expect, it } from 'vitest';

import { computeDropZone } from './tabDnd';

describe('computeDropZone', () => {
  const W = 400;
  const H = 200;

  it('returns center for the middle region', () => {
    expect(computeDropZone(W / 2, H / 2, W, H)).toBe('center');
  });

  it('picks the nearest edge when within the edge band', () => {
    expect(computeDropZone(10, H / 2, W, H)).toBe('left');
    expect(computeDropZone(W - 10, H / 2, W, H)).toBe('right');
    expect(computeDropZone(W / 2, 10, W, H)).toBe('top');
    expect(computeDropZone(W / 2, H - 10, W, H)).toBe('bottom');
  });

  it('a corner resolves to its nearest edge', () => {
    // Top-left corner: x frac 0.025 < y frac 0.05 -> left wins.
    expect(computeDropZone(10, 10, W, H)).toBe('left');
  });

  it('falls back to center for a zero-sized rect', () => {
    expect(computeDropZone(0, 0, 0, 0)).toBe('center');
  });
});