import { test } from 'node:test';
import assert from 'node:assert/strict';
import { Vector3 } from 'three';
import { createPrecipitation } from '../src/scene/precipitation.ts';

test('more precipitation draws more particles; mixed weather animates both and dry weather stops', (t) => {
  t.mock.method(Math, 'random', () => 0.5);
  const effect = createPrecipitation(() => -100);
  const camera = new Vector3(0, 10, 0);
  const [rain, snow] = effect.group.children as any[];
  try {
    assert.equal(effect.update(0, camera, 0, 0, 1, 600), false);
    effect.update(0, camera, 0.2, 0, 1, 600);
    const light = rain.geometry.drawRange.count;
    assert.ok(light > 0);
    assert.equal(snow.visible, false);
    const before = rain.geometry.attributes.position.getY(0);
    effect.update(0.01, camera, 0.2, 0, 1, 600);
    assert.ok(rain.geometry.attributes.position.getY(0) < before);
    assert.equal(effect.update(0.01, camera, 15, 2, 1, 600), true);
    assert.ok(rain.geometry.drawRange.count > light);
    assert.ok(snow.visible && snow.geometry.drawRange.count > 0);
    const snowBefore = snow.geometry.attributes.position.getY(0);
    effect.update(0.01, camera, 15, 2, 1, 600);
    assert.ok(snow.geometry.attributes.position.getY(0) < snowBefore);
    assert.equal(effect.update(0.01, camera, 0, 0, 1, 600), false);
    assert.equal(rain.visible || snow.visible, false);
  } finally { effect.dispose(); }
});

test('particles follow camera teleports and stay above the sampled ground', () => {
  const effect = createPrecipitation(() => 3);
  const camera = new Vector3(0, 10, 0);
  try {
    effect.update(0, camera, 8, 1, 1, 600);
    camera.set(1000, 20, -1000);
    effect.update(0.01, camera, 8, 1, 1, 600);
    for (const mesh of effect.group.children as any[]) {
      const positions = mesh.geometry.attributes.position;
      for (let i = 0; i < mesh.geometry.drawRange.count; i++) {
        assert.ok(Math.abs(positions.getX(i) - camera.x) < 25);
        assert.ok(Math.abs(positions.getZ(i) - camera.z) < 25);
        assert.ok(positions.getY(i) >= 3);
      }
    }
  } finally { effect.dispose(); }
});