import { describe, expect, it } from 'vitest';
import {
  CAPTION_HEIGHT,
  containRect,
  gridMetrics,
  TILE_GAP,
  TILE_MAX,
  TILE_MIN,
  tileAt,
  tileRect,
} from '../../src/editor/texture/imageGrid';

/** The width the picker gives its grid. */
const WIDTH = 560;

describe('gridMetrics', () => {
  it('fits as many columns as the width holds, and spreads the leftover across them', () => {
    const m = gridMetrics(WIDTH, 7);
    expect(m.columns).toBe(5);
    expect(m.tile).toBeGreaterThanOrEqual(TILE_MIN);
    expect(m.columns * m.tile + (m.columns - 1) * TILE_GAP).toBeLessThanOrEqual(WIDTH);
  });

  it('keeps one column in a width too narrow for even that', () => {
    expect(gridMetrics(40, 3).columns).toBe(1);
  });

  it('caps a lone tile instead of blowing one picture up over the whole dialog', () => {
    expect(gridMetrics(140, 1).tile).toBe(TILE_MAX);
  });

  it('reports the height the scroll container has to give it', () => {
    const m = gridMetrics(WIDTH, 7);
    expect(m.rows).toBe(2);
    expect(m.height).toBe(2 * (m.tile + CAPTION_HEIGHT) + TILE_GAP);
    expect(gridMetrics(WIDTH, 0).height).toBe(0);
  });
});

describe('tileRect', () => {
  it('lays the tiles out row by row', () => {
    const m = gridMetrics(WIDTH, 7);
    expect(tileRect(0, m)).toEqual({ x: 0, y: 0, w: m.tile, h: m.tile + CAPTION_HEIGHT });
    expect(tileRect(1, m).x).toBe(m.tile + TILE_GAP);
    expect(tileRect(1, m).y).toBe(0);
    expect(tileRect(m.columns, m)).toEqual({
      x: 0,
      y: m.tile + CAPTION_HEIGHT + TILE_GAP,
      w: m.tile,
      h: m.tile + CAPTION_HEIGHT,
    });
  });
});

describe('tileAt', () => {
  const m = gridMetrics(WIDTH, 7);

  it('finds the tile a point is on', () => {
    expect(tileAt(2, 2, 7, m)).toBe(0);
    expect(tileAt(m.tile + TILE_GAP + 2, 2, 7, m)).toBe(1);
    expect(tileAt(2, m.tile + CAPTION_HEIGHT + TILE_GAP + 2, 7, m)).toBe(m.columns);
  });

  it('takes nothing in the gaps between tiles', () => {
    expect(tileAt(m.tile + 2, 2, 7, m)).toBe(-1);
    expect(tileAt(2, m.tile + CAPTION_HEIGHT + 2, 7, m)).toBe(-1);
  });

  it('takes nothing past the last tile – the grid is filled to the box height', () => {
    // Seven pictures in five columns fill the second row up to place 6; 7 is the first empty one.
    expect(tileAt(tileRect(6, m).x + 2, tileRect(6, m).y + 2, 7, m)).toBe(6);
    expect(tileAt(tileRect(7, m).x + 2, tileRect(7, m).y + 2, 7, m)).toBe(-1);
    expect(tileAt(2, 4000, 7, m)).toBe(-1);
    expect(tileAt(-2, 2, 7, m)).toBe(-1);
  });
});

describe('containRect', () => {
  it('centres a picture and keeps its ratio', () => {
    expect(containRect(64, 32, 100, 100)).toEqual({ x: 0, y: 25, w: 100, h: 50 });
    expect(containRect(32, 64, 100, 100)).toEqual({ x: 25, y: 0, w: 50, h: 100 });
  });

  it('blows a small icon up to the box, so it is recognisable next to a sheet', () => {
    expect(containRect(16, 16, 100, 100)).toEqual({ x: 0, y: 0, w: 100, h: 100 });
  });

  it('has nothing to draw for a picture the server could not read', () => {
    expect(containRect(0, 0, 100, 100)).toEqual({ x: 0, y: 0, w: 0, h: 0 });
  });
});