// boot.js — the web layer: DOM, canvas, WebAudio. All game logic lives in
// src/; this file only binds engine events to browser things.

import { Engine } from "../src/core/engine.js";
import { AssetManifest } from "../src/render/assets.js";
import { RoomRenderer } from "../src/render/canvas.js";
import { HudModel } from "../src/render/hud.js";

const spec = await (await fetch("/example/game.json")).json();
const engine = new Engine(spec);
window.__engine = engine;   // dev/debug hook
const assets = new AssetManifest(spec.assets ?? []);

// ---- images ---------------------------------------------------------------
const images = new Map();
await Promise.all((spec.assets ?? [])
  .filter((a) => /\.(png|jpe?g|webp|gif)$/i.test(a.file))
  .map((a) => new Promise((res) => {
    const img = new Image();
    img.onload = () => { images.set(a.id, img); res(); };
    img.onerror = () => res();          // placeholder boxes cover missing art
    img.src = "/" + a.file;
  })));

const renderer = new RoomRenderer(engine.compiled, assets, images);
const hud = new HudModel(engine);

// ---- audio (WebAudio, with loop points like the MIDI convention) ---------
let actx = null, musicNodes = [], master = null;
const gain = () => {
  if (!master) { master = actx.createGain(); master.connect(actx.destination); }
  master.gain.value = +volEl.value;
  return master;
};
const buffers = new Map();
async function bufferFor(def) {
  if (buffers.has(def.id)) return buffers.get(def.id);
  const r = await fetch("/" + def.file);
  if (!r.ok) { console.warn("[audio] missing file:", def.file); buffers.set(def.id, null); return null; }
  const buf = await actx.decodeAudioData(await r.arrayBuffer());
  buffers.set(def.id, buf);
  return buf;
}
function stopMusic() { for (const n of musicNodes) { try { n.stop(); } catch {} } musicNodes = []; }
async function playMusic(def) {
  stopMusic();
  const buf = await bufferFor(def);
  if (!buf) return;
  const src = actx.createBufferSource();
  src.buffer = buf;
  if (def.loopStartMs != null && def.loopEndMs != null) {
    src.loop = true; src.loopStart = def.loopStartMs / 1000; src.loopEnd = def.loopEndMs / 1000;
    src.start(0, 0, def.loopStartMs / 1000);          // play intro head once
    const later = actx.createBufferSource();          // then the loop body forever
    later.buffer = buf; later.loop = true;
    later.loopStart = def.loopStartMs / 1000; later.loopEnd = def.loopEndMs / 1000;
    later.start(actx.currentTime + def.loopStartMs / 1000, def.loopStartMs / 1000);
    const g = gain(); src.connect(g); later.connect(g);
    musicNodes.push(src, later);
  } else {
    src.loop = true;
    const g = gain(); src.connect(g); src.start();
    musicNodes.push(src);
  }
}
async function playSfx(def) {
  const buf = await bufferFor(def);
  if (!buf) return;
  const src = actx.createBufferSource(); src.buffer = buf;
  src.connect(gain()); src.start();
}
engine.emitter.on("playMusic", async (ev) => {
  const def = (spec.music ?? []).find((m) => m.id === ev.track);
  if (def && actx) await playMusic(def);
});
engine.emitter.on("stopMusic", stopMusic);
engine.emitter.on("playSfx", async (ev) => {
  const def = (spec.sfx ?? []).find((s) => s.id === ev.sfx);
  if (def && actx) await playSfx(def);
});

// ---- DOM binding ----------------------------------------------------------
const cv = document.getElementById("cv");
const ctx = cv.getContext("2d");
const verbsEl = document.getElementById("verbs");
const textbox = document.getElementById("textbox");
const squares = document.getElementById("squares");
const titleEl = document.getElementById("title");
const volEl = document.getElementById("vol");

function drawVerbs() {
  verbsEl.innerHTML = "";
  for (const v of hud.verbs()) {
    const b = document.createElement("button");
    b.textContent = v.label;
    b.className = v.selected ? "selected" : "";
    b.onclick = () => { engine.selectVerb(v.id); drawVerbs(); };
    verbsEl.appendChild(b);
  }
}
function drawSquares() {
  squares.innerHTML = "";
  for (const c of hud.dialogueChoices()) {
    const b = document.createElement("button");
    b.textContent = c.text;
    b.onclick = () => { engine.chooseDialogue(c.index); drawSquares(); };
    squares.appendChild(b);
  }
}
engine.emitter.on("say", (ev) => { textbox.textContent = ev.text; });
engine.emitter.on("dialogueLine", (ev) => {
  textbox.textContent = (ev.speaker ? ev.speaker.toUpperCase() + ": " : "") + ev.text;
  drawSquares();
});
engine.emitter.on("dialogueEnd", () => drawSquares());
engine.emitter.on("roomEnter", () => { textbox.textContent = ""; drawSquares(); });

cv.addEventListener("click", (e) => {
  const r = cv.getBoundingClientRect();
  const x = (e.clientX - r.left) * (cv.width / r.width);
  const y = (e.clientY - r.top) * (cv.height / r.height);
  if (engine.selectedVerb) {
    const t = engine.hitTest(x, y);
    if (t.kind !== "walkable") engine.click(t);
    else engine.clickPoint(x, y);
  } else {
    engine.clickPoint(x, y);
  }
});

// keyboard: number keys pick verbs, Esc clears, Space skips
addEventListener("keydown", (e) => {
  if (titleEl.style.display !== "none") return begin();
  const n = +e.key;
  if (n >= 1 && n <= hud.verbs().length) { engine.selectVerb(hud.verbs()[n - 1].id); drawVerbs(); }
  if (e.key === "Escape") { engine.selectVerb(null); drawVerbs(); }
  if (e.key === " " && engine.scene) engine.skipScene();
});
document.getElementById("skip").onclick = () => engine.scene && engine.skipScene();
document.getElementById("save").onclick = () => {
  if (hud.canSave()) localStorage.setItem("moonlit-save", engine.save());
};
document.getElementById("load").onclick = () => {
  const s = localStorage.getItem("moonlit-save");
  if (s) { engine.load(s); titleEl.style.display = "none"; }
};
volEl.oninput = () => { if (master) master.gain.value = +volEl.value; };

function begin() {
  titleEl.style.display = "none";
  actx ??= new AudioContext();
  engine.newGame();
  engine.startScene("intro");
}
titleEl.onclick = begin;

// ---- main loop ------------------------------------------------------------
let last = performance.now();
function frame(now) {
  engine.tick(now - last); last = now;
  renderer.draw(engine, ctx, { timeMs: now });
  requestAnimationFrame(frame);
}
drawVerbs();
requestAnimationFrame(frame);