// TURNCRAFT — Lane A standalone demo.  Run: `npm run dev` → open /demo-engine.html
//
// WHAT TO LOOK AT / PRESS (maps to the acceptance criteria in LANE_A_ENGINE.md):
//  • Full-size (448×160×256) empty world + a test pattern near the origin renders
//    at 60 fps with few draw calls — see the HUD (top-left): FPS, draw calls,
//    triangles, meshes. Draw calls stay well under 300.
//  • AO: orbit into the hollow steel CAVE (left) — inner corners visibly darken;
//    no cracks or z-fighting where chunks meet.
//  • Transparency: the GLASS ARCH and the BLUE VINYL wall (in front of a cream
//    wall) render in a correct transparent pass over the opaque blocks behind.
//  • All 10 patterns + every block id: the labeled PILLAR ROW — one stepped
//    pillar per block id, each with a floating "id name" label.
//  • Emissive: the LED WALL. Drag the "emissive boost" slider (0→3) — LED/strobe
//    glow scales; nothing else changes.
//  • Dirty remeshing: press "TORTURE" — ~500 random block edits/sec in the flicker
//    cube; FPS stays ≳55 and edits appear within ~1–2 frames.
//
// Uses ONLY Lane A code + core. OrbitControls is a demo convenience (not shipped
// in the engine API).

import * as THREE from 'three';
import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls.js';
import { WORLD_X, WORLD_Y, WORLD_Z } from '../core/constants';
import { BLOCKS, BLOCK_BY_NAME } from '../core/blocks';
import { createRenderer } from '../engine/renderer';
import { VoxelWorld } from '../engine/VoxelWorld';
import { ChunkManager } from '../engine/ChunkManager';

const B = (name: string) => BLOCK_BY_NAME.get(name)!.id;

const app = document.getElementById('app')!;
const { renderer, scene, camera, atlas, setEmissiveBoost, setBloom, render } = createRenderer(app);

let hud: HTMLDivElement; // populated by buildHud(), read by updateHud()

const world = new VoxelWorld(WORLD_X, WORLD_Y, WORLD_Z);
buildTestPattern(world);

const chunks = new ChunkManager(world, scene, atlas, 4);
const buildT0 = performance.now();
chunks.buildAll();
const buildMs = performance.now() - buildT0;

// Camera / controls framed on the test pattern.
camera.position.set(34, 46, 118);
const controls = new OrbitControls(camera, renderer.domElement);
controls.target.set(33, 8, 33);
controls.enableDamping = true;
controls.dampingFactor = 0.08;
controls.update();

// DEBUG: dev-only hook so a camera can be flown to a viewpoint for inspection.
(window as unknown as { __demo?: unknown }).__demo = {
  scene, atlas, camera, controls, setBloom, setEmissiveBoost,
  look(px: number, py: number, pz: number, tx: number, ty: number, tz: number) {
    camera.position.set(px, py, pz);
    controls.target.set(tx, ty, tz);
    controls.update();
    render();
  },
  render,
};

// Floating labels over each pillar.
addPillarLabels(scene);

buildHud();

// --- main loop ---
let last = performance.now();
let fps = 60, minFpsTorture = 999;
let torturing = false;

function frame() {
  const t = performance.now();
  const dt = Math.min(0.1, (t - last) / 1000);
  last = t;
  fps = fps * 0.9 + (1 / Math.max(1e-3, dt)) * 0.1;

  if (torturing) {
    torture(dt);
    if (fps < minFpsTorture) minFpsTorture = fps;
  }

  controls.update();
  chunks.update();
  render();
  updateHud(dt);
  requestAnimationFrame(frame);
}
requestAnimationFrame(frame);

// ---------------------------------------------------------------------------
// Test pattern
// ---------------------------------------------------------------------------
function buildTestPattern(w: VoxelWorld): void {
  // 64×64 plywood floor at y=0.
  w.fillBox(2, 0, 2, 65, 0, 65, B('plywood'));

  // Labeled pillar row: one stepped pillar per block id (skip air id 0).
  for (const def of BLOCKS) {
    if (def.id === 0) continue;
    const x = 3 + def.id * 2;
    const h = 2 + (def.id % 7);
    w.fillBox(x, 1, 6, x, h, 6, def.id);
  }

  // Glass arch (transparent portal) — see through it to the pillars/floor.
  w.fillBox(10, 1, 40, 11, 8, 41, B('glass'));
  w.fillBox(20, 1, 40, 21, 8, 41, B('glass'));
  w.fillBox(10, 8, 40, 21, 9, 41, B('glass'));

  // Blue translucent vinyl wall in front of a cream label wall.
  w.fillBox(30, 1, 46, 40, 6, 46, B('label_cream'));
  w.fillBox(30, 1, 44, 40, 6, 44, B('vinyl_blue'));

  // LED wall — mixed colours + strobe dots (emissive slider test).
  const leds = [B('led_red'), B('led_green'), B('led_amber'), B('led_blue')];
  for (let x = 48; x <= 58; x++)
    for (let y = 1; y <= 8; y++) {
      const id = (x + y) % 5 === 0 ? B('strobe_dot') : leds[x % 4];
      w.setBlock(x, y, 40, id);
    }

  // Hollow steel cave — AO test on interior corners, with an entrance.
  w.fillBox(2, 1, 50, 20, 12, 64, B('steel_grey'));
  w.fillBox(4, 2, 52, 18, 11, 63, 0);        // hollow it
  w.fillBox(9, 1, 50, 13, 6, 50, 0);         // doorway on the front face
}

// ---------------------------------------------------------------------------
// Torture: ~500 random edits/sec in a flicker cube (dirty-remesh stress).
// ---------------------------------------------------------------------------
const TZ = { x0: 4, x1: 28, y0: 1, y1: 24, z0: 20, z1: 44 };
const TORTURE_BLOCKS = [0, B('steel_grey'), B('vinyl_blue'), B('led_green'), B('brushed_alu')];
let editCarry = 0;
function torture(dt: number): void {
  editCarry += 500 * dt;
  const n = editCarry | 0;
  editCarry -= n;
  for (let i = 0; i < n; i++) {
    const x = TZ.x0 + ((Math.random() * (TZ.x1 - TZ.x0 + 1)) | 0);
    const y = TZ.y0 + ((Math.random() * (TZ.y1 - TZ.y0 + 1)) | 0);
    const z = TZ.z0 + ((Math.random() * (TZ.z1 - TZ.z0 + 1)) | 0);
    world.setBlock(x, y, z, TORTURE_BLOCKS[(Math.random() * TORTURE_BLOCKS.length) | 0]);
  }
}

// ---------------------------------------------------------------------------
// Labels + HUD
// ---------------------------------------------------------------------------
function addPillarLabels(sc: THREE.Scene): void {
  for (const def of BLOCKS) {
    if (def.id === 0) continue;
    const x = 3 + def.id * 2;
    const h = 2 + (def.id % 7);
    const sprite = makeTextSprite(`${def.id} ${def.name}`);
    sprite.position.set(x + 0.5, h + 2.2, 6.5);
    sc.add(sprite);
  }
}

function makeTextSprite(text: string): THREE.Sprite {
  const pad = 6, fs = 22;
  const c = document.createElement('canvas');
  const ctx = c.getContext('2d')!;
  ctx.font = `${fs}px monospace`;
  const w = Math.ceil(ctx.measureText(text).width) + pad * 2;
  const hgt = fs + pad * 2;
  c.width = w; c.height = hgt;
  ctx.font = `${fs}px monospace`;
  ctx.fillStyle = 'rgba(10,10,12,0.72)';
  ctx.fillRect(0, 0, w, hgt);
  ctx.fillStyle = '#e8e6df';
  ctx.textBaseline = 'middle';
  ctx.fillText(text, pad, hgt / 2);
  const tex = new THREE.CanvasTexture(c);
  tex.colorSpace = THREE.SRGBColorSpace;
  const mat = new THREE.SpriteMaterial({ map: tex, depthTest: true, transparent: true });
  const s = new THREE.Sprite(mat);
  s.scale.set((w / hgt) * 2.2, 2.2, 1);
  return s;
}

function buildHud(): void {
  hud = document.createElement('div');
  hud.style.cssText =
    'position:fixed;top:8px;left:8px;font:12px/1.5 monospace;color:#d8d6cf;' +
    'background:rgba(10,9,8,0.72);padding:10px 12px;border-radius:6px;white-space:pre;' +
    'user-select:none;pointer-events:none;z-index:10';
  document.body.appendChild(hud);

  const panel = document.createElement('div');
  panel.style.cssText =
    'position:fixed;top:8px;right:8px;font:12px monospace;color:#d8d6cf;' +
    'background:rgba(10,9,8,0.8);padding:10px 12px;border-radius:6px;z-index:10;' +
    'display:flex;flex-direction:column;gap:8px;align-items:stretch';

  const btn = document.createElement('button');
  btn.textContent = 'TORTURE: off';
  btn.style.cssText = 'font:12px monospace;padding:6px 10px;cursor:pointer';
  btn.onclick = () => {
    torturing = !torturing;
    if (torturing) minFpsTorture = 999;
    btn.textContent = torturing ? 'TORTURE: ON (500 edits/s)' : 'TORTURE: off';
  };

  const label = document.createElement('label');
  label.style.cssText = 'display:flex;flex-direction:column;gap:2px';
  label.textContent = 'emissive boost';
  const slider = document.createElement('input');
  slider.type = 'range'; slider.min = '0'; slider.max = '3'; slider.step = '0.05'; slider.value = '1';
  const val = document.createElement('span');
  val.textContent = '1.00';
  slider.oninput = () => { setEmissiveBoost(+slider.value); val.textContent = (+slider.value).toFixed(2); };
  label.appendChild(slider);
  label.appendChild(val);

  panel.appendChild(btn);
  panel.appendChild(label);
  document.body.appendChild(panel);
}

let hudAccum = 0;
function updateHud(dt: number): void {
  hudAccum += dt;
  if (hudAccum < 0.2) return; // refresh ~5×/s
  hudAccum = 0;
  const calls = renderer.info.render.calls;
  const tris = renderer.info.render.triangles;
  hud.textContent =
    `TURNCRAFT — Lane A engine demo\n` +
    `world      ${WORLD_X}×${WORLD_Y}×${WORLD_Z}  (initial build ${buildMs.toFixed(0)} ms)\n` +
    `fps        ${fps.toFixed(0)}${torturing ? `   (min under torture ${minFpsTorture.toFixed(0)})` : ''}\n` +
    `draw calls ${calls}\n` +
    `triangles  ${tris.toLocaleString()}\n` +
    `meshes     ${chunks.meshCount}\n` +
    `dirty      ${world.dirtyCount}   remesh ${chunks.lastRemeshMs.toFixed(2)} ms / ${chunks.lastRemeshCount} chunk(s)`;
}