import test from "node:test";
import assert from "node:assert/strict";
import { Renderer } from "../renderer.js";

function meshFixture() {
  const renderer = Object.create(Renderer.prototype);
  renderer.sections = new Map([
    ["-2,0,0", { name: "leaving" }],
    ["-1,0,0", { name: "border" }],
    ["0,0,0", { name: "retained" }],
    ["1,0,0", { name: "far" }],
  ]);
  renderer.dirty = new Set();
  renderer.disposed = [];
  renderer.disposeMesh = (mesh) => renderer.disposed.push(mesh);
  return renderer;
}

test("stream unload disposes only departing meshes and keeps visible mesh identities", () => {
  const renderer = meshFixture();
  const before = new Map(renderer.sections);
  renderer.dirty.add("-2,0,0");
  renderer.unloadSections([[-2, 0, 0]]);
  assert.deepEqual(renderer.disposed, [before.get("-2,0,0")]);
  for (const id of ["-1,0,0", "0,0,0", "1,0,0"])
    assert.equal(renderer.sections.get(id), before.get(id));
  assert.deepEqual([...renderer.dirty], ["-1,0,0"]);
});

test("incoming cells queue their section and boundaries without clearing existing geometry", () => {
  const renderer = meshFixture();
  const before = [...renderer.sections.values()];
  renderer.change([{ pos: [32, 5, 5], block: 7 }]);
  assert.deepEqual([...renderer.sections.values()], before);
  assert.equal(renderer.disposed.length, 0);
  assert.deepEqual([...renderer.dirty].sort(), ["1,0,0", "2,0,0"]);
});

test("unloading adjacent sections does not queue either for reconstruction", () => {
  const renderer = meshFixture();
  renderer.change([{ pos: [-17, 0, 0], block: 0 }]);
  renderer.unloadSections([[-2, 0, 0], [-1, 0, 0]]);
  assert.equal(renderer.dirty.has("-2,0,0"), false);
  assert.equal(renderer.dirty.has("-1,0,0"), false);
  assert.equal(renderer.dirty.has("0,0,0"), true);
  assert.equal(renderer.sections.size, 2);
});