import test, { after, afterEach } from "node:test";
import assert from "node:assert/strict";
import { readFile } from "node:fs/promises";
import { BlockLightController } from "../block-light-controller.js";
import { buildBlockLight } from "../block-light.js";
import { loadLightProperties } from "../light-properties.js";

const properties = JSON.parse(
  await readFile(new URL("../light-properties.json", import.meta.url)),
);
const savedWorker = globalThis.Worker,
  savedFetch = globalThis.fetch;
const controllers = [];
class FakeWorker {
  constructor() {
    this.packets = [];
    this.terminated = false;
  }
  postMessage(packet) {
    this.packets.push(structuredClone(packet));
  }
  terminate() {
    this.terminated = true;
  }
  reply(index) {
    const packet = this.packets[index];
    const { min, size, data, sourceCount, blockLevels, skyLevels } =
      buildBlockLight(
        new Map(packet.blocks),
        new Map(packet.materials),
        packet.bounds,
      );
    this.onmessage({
      data: {
        generation: packet.generation,
        field: { min, size, data, sourceCount, blockLevels, skyLevels },
        milliseconds: 1,
      },
    });
  }
}
globalThis.Worker = FakeWorker;
globalThis.fetch = async () => ({ ok: true, json: async () => properties });
afterEach(() => {
  for (const controller of controllers.splice(0)) {
    clearTimeout(controller.timer);
    controller.worker?.terminate();
  }
});
after(() => {
  if (savedWorker === undefined) delete globalThis.Worker;
  else globalThis.Worker = savedWorker;
  globalThis.fetch = savedFetch;
});
const bounds = { min: [-2, 0, -2], max: [2, 3, 2] };
const materials = new Map([
  [1, { state: "minecraft:torch", light: 14, render: [] }],
  [
    2,
    {
      state: "minecraft:sea_lantern",
      light: 15,
      render: [{ min: [0, 0, 0], max: [1, 1, 1] }],
    },
  ],
]);
function fixture() {
  const published = [];
  const controller = new BlockLightController((field) => published.push(field));
  controllers.push(controller);
  return { controller, worker: controller.worker, published };
}

test("requests awaiting metadata coalesce into the latest complete world", async () => {
  const { controller, worker, published } = fixture();
  controller.request(new Map([["0,1,0", 1]]), materials, bounds);
  controller.request(new Map([["1,1,0", 2]]), materials, bounds);
  await loadLightProperties();
  controller.start();
  assert.equal(worker.packets.length, 1);
  assert.equal(worker.packets[0].generation, 2);
  assert.deepEqual(worker.packets[0].blocks, [["1,1,0", 2]]);
  worker.reply(0);
  assert.equal(published.length, 1);
  assert.equal(published[0].sample([1, 1, 0]).blockLevel, 15);
  assert.equal(controller.status, "ready");
});

test("an old world's in-flight result is discarded before publishing the replacement world", async () => {
  const { controller, worker, published } = fixture();
  await loadLightProperties();
  const first = new Map([["0,1,0", 1]]);
  controller.request(first, materials, bounds);
  controller.start();
  controller.request(new Map([["1,1,0", 2]]), materials, bounds);
  first.clear();
  assert.equal(worker.packets.length, 1);
  worker.reply(0);
  assert.equal(published.length, 0);
  assert.equal(worker.packets.length, 2);
  worker.reply(1);
  assert.equal(published.length, 1);
  assert.equal(published[0].sample([1, 1, 0]).blockLevel, 15);
  assert.equal(controller.pending, null);
  assert.equal(controller.busy, false);
});

test("rapid edits during a build coalesce while the last valid field remains available", async () => {
  const { controller, worker, published } = fixture();
  await loadLightProperties();
  const blocks = new Map([["0,1,0", 1]]);
  controller.request(blocks, materials, bounds);
  controller.start();
  worker.reply(0);
  const retained = published[0];
  blocks.set("0,1,0", 2);
  controller.request(blocks, materials, bounds);
  controller.start();
  blocks.set("1,1,0", 1);
  controller.request(blocks, materials, bounds);
  blocks.clear();
  controller.request(blocks, materials, bounds);
  assert.equal(published.length, 1);
  assert.equal(retained.sample([0, 1, 0]).blockLevel, 14);
  worker.reply(1);
  assert.equal(worker.packets.length, 3);
  assert.equal(worker.packets[2].generation, 4);
  assert.deepEqual(worker.packets[2].blocks, []);
  assert.equal(published.length, 1);
  worker.reply(2);
  assert.equal(published.length, 2);
  assert.equal(published[1].sourceCount, 0);
  assert.equal(published[1].sample([0, 1, 0]).blockLevel, 0);
});

test("worker failure recovers using the newest queued world and the same solver", async () => {
  const { controller, worker, published } = fixture();
  await loadLightProperties();
  controller.request(new Map([["0,1,0", 1]]), materials, bounds);
  controller.start();
  controller.request(new Map([["1,1,0", 2]]), materials, bounds);
  let prevented = false;
  worker.onerror({
    preventDefault() {
      prevented = true;
    },
  });
  assert.equal(prevented, true);
  assert.equal(worker.terminated, true);
  assert.equal(controller.worker, null);
  // Resolve through publish rather than a timing assumption about the fallback.
  await new Promise((resolve, reject) => {
    const timeout = setTimeout(
      () => reject(Error("Fallback lighting did not finish")),
      1000,
    );
    const publish = controller.publish;
    controller.publish = (field) => {
      clearTimeout(timeout);
      publish(field);
      resolve();
    };
  });
  assert.equal(published.length, 1);
  assert.equal(published[0].sample([1, 1, 0]).blockLevel, 15);
  assert.equal(controller.status, "ready");
});

test("a duplicate stale reply cannot mark a newer build idle or start a concurrent job", async () => {
  const { controller, worker, published } = fixture();
  await loadLightProperties();
  controller.request(new Map([["0,1,0", 1]]), materials, bounds);
  controller.start();
  controller.request(new Map([["1,1,0", 2]]), materials, bounds);
  worker.reply(0);
  assert.equal(worker.packets.length, 2);
  assert.equal(controller.busy, true);
  worker.reply(0);
  assert.equal(controller.busy, true);
  controller.request(new Map([["-1,1,0", 1]]), materials, bounds);
  controller.start();
  assert.equal(worker.packets.length, 2);
  assert.equal(published.length, 0);
  worker.reply(1);
  assert.equal(worker.packets.length, 3);
  worker.reply(2);
  assert.equal(published.length, 1);
  assert.equal(published[0].sample([-1, 1, 0]).blockLevel, 14);
  worker.reply(2);
  assert.equal(published.length, 1);
});

test("synchronous Worker construction failure still publishes light from the fallback solver", async () => {
  const previousWorker = globalThis.Worker;
  globalThis.Worker = class {
    constructor() {
      throw new Error("Worker blocked by browser policy");
    }
  };
  let context;
  try {
    context = fixture();
  } finally {
    globalThis.Worker = previousWorker;
  }
  const { controller, published } = context;
  assert.equal(controller.worker, null);
  const completed = new Promise((resolve, reject) => {
    const timeout = setTimeout(
      () => reject(Error("Fallback lighting did not finish")),
      1000,
    );
    const publish = controller.publish;
    controller.publish = (field) => {
      clearTimeout(timeout);
      publish(field);
      resolve();
    };
  });
  controller.request(new Map([["0,1,0", 1]]), materials, bounds);
  await loadLightProperties();
  controller.start();
  await completed;
  assert.equal(published.length, 1);
  assert.equal(published[0].sample([0, 1, 0]).blockLevel, 14);
  assert.equal(controller.status, "ready");
});