// boot.js (Lane F) — the shell. Creates renderer/scene/loop, picks the world (real or
// stub), hosts the debug camera + DBG. Lanes: request wiring via NOTES, don't edit here.

import * as THREE from 'three';
import { parseFlags } from './core/flags.js';
import { createRng } from './core/rng.js';
import { createBus } from './core/bus.js';
import { createWorld as createStubWorld, STUB_LEVEL } from './stub/world_stub.js';

const flags = parseFlags();
const bus = createBus();

const renderer = new THREE.WebGLRenderer({ antialias: true, preserveDrawingBuffer: true });
renderer.setPixelRatio(Math.min(devicePixelRatio, 2));
renderer.setSize(innerWidth, innerHeight);
document.getElementById('game').appendChild(renderer.domElement);

const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera(75, innerWidth / innerHeight, 0.1, 600);

async function pickWorld() {
  if (!flags.stub) {
    try {
      const mod = await import('./world/index.js');           // Lane A's world, when it lands
      const level = await loadLevel(flags.lvl);
      return mod.createWorld(level, { rng: createRng(flags.seed ?? level.seed) });
    } catch (e) {
      console.info('[boot] Lane A world not available, using stub —', e.message);
    }
  }
  return createStubWorld(STUB_LEVEL, { rng: createRng(flags.seed ?? STUB_LEVEL.seed) });
}
async function loadLevel(id) {
  const mod = await import('./levels/index.js');              // Lane C's registry, when it lands
  return mod.getLevel(id);
}

const world = await pickWorld();
scene.add(world.group);
scene.background = new THREE.Color(world.biomeAt(0).palette.void);

// --- debug drift/fly camera (placeholder until Lane B's player rig; ?fly=1 = manual) ---
let sCam = 5, look = { yaw: 0, pitch: 0 }, dragging = false, speed = world.biomeAt(0).flow * 0.6;
const keys = new Set();
addEventListener('keydown', (e) => keys.add(e.code));
addEventListener('keyup', (e) => keys.delete(e.code));
addEventListener('mousedown', () => (dragging = true));
addEventListener('mouseup', () => (dragging = false));
addEventListener('mousemove', (e) => {
  if (!dragging) return;
  look.yaw -= e.movementX * 0.003;
  look.pitch = THREE.MathUtils.clamp(look.pitch - e.movementY * 0.003, -1.2, 1.2);
});

function updateCamera(dt) {
  if (flags.fly) {
    if (keys.has('KeyW')) sCam += speed * 2 * dt;
    if (keys.has('KeyS')) sCam -= speed * 2 * dt;
  } else {
    sCam += speed * dt;                                        // title-screen auto-drift
  }
  sCam = ((sCam % world.length) + world.length) % world.length;
  const f = world.sample(sCam), ahead = world.sample(Math.min(sCam + 12, world.length));
  camera.position.copy(f.pos).addScaledVector(f.nor, -f.radius * 0.25);
  const target = ahead.pos.clone()
    .addScaledVector(f.bin, Math.sin(look.yaw) * 8)
    .addScaledVector(f.nor, Math.sin(look.pitch) * 8);
  camera.up.copy(f.nor);
  camera.lookAt(target);
}

// --- DBG (?dbg=1) — cite these numbers in NOTES; DBG.shot('name') saves a frame ---
const dbgEl = document.getElementById('dbg');
let frames = 0, fpsT = 0, fps = 0;
renderer.info.autoReset = false;                 // three resets info at render end — cache per-frame instead
const stats = { draws: 0, tris: 0 };
window.DBG = {
  get draws() { return stats.draws; },
  get tris() { return stats.tris; },
  get fps() { return fps; },
  world,
  shot(name = 'shot') {
    const a = document.createElement('a');
    a.download = `${name}.png`;
    a.href = renderer.domElement.toDataURL('image/png');
    a.click();
  },
};

addEventListener('resize', () => {
  camera.aspect = innerWidth / innerHeight;
  camera.updateProjectionMatrix();
  renderer.setSize(innerWidth, innerHeight);
});

let last = performance.now();
function frame(now) {
  const dt = Math.min((now - last) / 1000, 0.05);
  last = now;
  world.update(dt, sCam);
  updateCamera(dt);
  renderer.render(scene, camera);
  stats.draws = renderer.info.render.calls;
  stats.tris = renderer.info.render.triangles;
  renderer.info.reset();
  frames++; fpsT += dt;
  if (fpsT >= 0.5) {
    fps = Math.round(frames / fpsT); frames = 0; fpsT = 0;
    if (flags.dbg && !flags.shots)
      dbgEl.textContent = `${fps} fps · ${DBG.draws} draws · ${(DBG.tris / 1000) | 0}k tris · s=${sCam.toFixed(0)} · ${world.level?.id ?? '?'} ${world.hash?.() ?? ''}`;
  }
  requestAnimationFrame(frame);
}
if (flags.dbg && !flags.shots) dbgEl.style.display = 'block';
requestAnimationFrame(frame);

export { scene, camera, renderer, bus, flags, world };   // read-only handles for lanes