foodmageddon/tests/ops.test.ts

import { describe, expect, it } from 'vitest';
import { Rng } from '../src/shared/rng';
import { TerrainBitmap } from '../src/shared/terrain/bitmap';
import { applyOp, isValidOp, type TerrainOp } from '../src/shared/terrain/ops';
import { bitmapFrom, realMaterials } from './helpers';

const materials = realMaterials();

function filled(w: number, h: number, mat: number): TerrainBitmap {
  return new TerrainBitmap(w, h, new Uint8Array(w * h).fill(mat));
}

function randomOps(seed: number, count: number, w: number, h: number): TerrainOp[] {
  const rng = new Rng(seed);
  const ops: TerrainOp[] = [];
  for (let i = 0; i < count; i++) {
    const x = rng.int(0, w - 1);
    const y = rng.int(0, h - 1);
    const r = rng.int(1, 30);
    const k = rng.int(0, 2);
    if (k === 0) ops.push({ kind: 'carve', x, y, r, power: rng.int(0, 80) });
    else if (k === 1) ops.push({ kind: 'fill', x, y, r, material: rng.int(1, 5) });
    else ops.push({ kind: 'convert', x, y, r, from: 1, to: 8 });
  }
  return ops;
}

describe('terrain ops', () => {
  it('carve removes destructible pixels within the radius only', () => {
    const bm = filled(21, 21, 1);
    const res = applyOp(bm, { kind: 'carve', x: 10, y: 10, r: 3, power: 50 }, materials);
    expect(bm.get(10, 10)).toBe(0);
    expect(bm.get(13, 10)).toBe(0);
    expect(bm.get(14, 10)).toBe(1);
    expect(bm.get(12, 12)).toBe(0); // 2² + 2² = 8 <= 9
    expect(bm.get(13, 11)).toBe(1); // 3² + 1² = 10 > 9
    expect(res.removedByMaterial.get(1)).toBe(29); // integer disc of radius 3 has 29 pixels
  });

  it('power is compared to hardness: chocolate resists a weak carve', () => {
    const bm = filled(9, 9, 2);
    applyOp(bm, { kind: 'carve', x: 4, y: 4, r: 3, power: 40 }, materials);
    expect(bm.get(4, 4)).toBe(2);
    applyOp(bm, { kind: 'carve', x: 4, y: 4, r: 3, power: 60 }, materials);
    expect(bm.get(4, 4)).toBe(0);
  });

  it('the plate is indestructible', () => {
    const bm = filled(9, 9, 255);
    const res = applyOp(bm, { kind: 'carve', x: 4, y: 4, r: 4, power: 0xffff }, materials);
    expect(res.changed).toBeNull();
    expect(bm.get(4, 4)).toBe(255);
  });

  it('fill only writes empty pixels; convert only touches the source material', () => {
    const bm = bitmapFrom(['.....', '.111.', '.121.', '.111.', '.....']);
    applyOp(bm, { kind: 'fill', x: 2, y: 2, r: 2, material: 7 }, materials);
    expect(bm.get(2, 0)).toBe(7);
    expect(bm.get(2, 2)).toBe(2);
    expect(bm.get(1, 1)).toBe(1);
    applyOp(bm, { kind: 'convert', x: 2, y: 2, r: 2, from: 1, to: 8 }, materials);
    expect(bm.get(1, 1)).toBe(8);
    expect(bm.get(2, 2)).toBe(2);
    expect(bm.get(2, 0)).toBe(7);
  });

  it('ops are clamped at the map border', () => {
    const bm = filled(10, 10, 1);
    expect(() => applyOp(bm, { kind: 'carve', x: -5, y: 12, r: 8, power: 99 }, materials)).not.toThrow();
    expect(bm.get(0, 9)).toBe(0);
  });

  it('rejects invalid ops (floats, plate fill, unknown kind)', () => {
    expect(isValidOp({ kind: 'carve', x: 1.5, y: 1, r: 3, power: 1 })).toBe(false);
    expect(isValidOp({ kind: 'fill', x: 1, y: 1, r: 3, material: 255 })).toBe(false);
    expect(isValidOp({ kind: 'nuke', x: 1, y: 1, r: 3 })).toBe(false);
    expect(isValidOp({ kind: 'carve', x: 1, y: 1, r: 3, power: 1 })).toBe(true);
  });

  it('is deterministic: same op sequence -> bit-identical bitmaps', () => {
    const ops = randomOps(42, 500, 256, 128);
    const a = filled(256, 128, 1);
    const b = filled(256, 128, 1);
    for (const op of ops) applyOp(a, op, materials);
    for (const op of ops) applyOp(b, op, materials);
    expect(a.hash()).toBe(b.hash());
    expect(Buffer.from(a.data).equals(Buffer.from(b.data))).toBe(true);
    // Golden value: changing it means the op semantics changed, which breaks network compatibility.
    expect(a.hash()).toMatchInlineSnapshot(`2655657281`);
  });

  it('marks the chunks around the change dirty', () => {
    const bm = filled(256, 256, 1);
    bm.takeDirtyChunks();
    applyOp(bm, { kind: 'carve', x: 64, y: 10, r: 2, power: 99 }, materials);
    // Change straddles the chunk border at x = 64 -> chunks 0 and 1 of the first row.
    expect(bm.takeDirtyChunks()).toEqual([0, 1]);
    expect(bm.takeDirtyChunks()).toEqual([]);
  });
});