// ═══════════════════════════════════════════════════════
//  ITEMS — decorative floating "?" bonus boxes
//  Purely ambient trackside dressing (no gameplay effect):
//  they hover just beyond the road edge, spin and bob, and
//  glow warmly in the sunset light. The original build gave
//  every box its own real PointLight (10 extra lights!); this
//  version uses emissive materials + one additive glow sprite
//  per box instead — zero additional lights.
// ═══════════════════════════════════════════════════════
import * as THREE from 'three';
import { TRACK_WIDTH, CURB_W } from './config.js';
import { frame } from './track.js';

// ── Shared assets (built once) ──

let _shared = null;
function getShared() {
  if (_shared) return _shared;

  // "?" decal texture — warm amber tile with a bold question mark
  const qCanvas = document.createElement('canvas');
  qCanvas.width = qCanvas.height = 128;
  const qctx = qCanvas.getContext('2d');
  const grad = qctx.createLinearGradient(0, 0, 0, 128);
  grad.addColorStop(0, '#ffc85e');
  grad.addColorStop(1, '#f09120');
  qctx.fillStyle = grad;
  qctx.fillRect(0, 0, 128, 128);
  qctx.strokeStyle = 'rgba(60,30,5,0.9)';
  qctx.lineWidth = 8;
  qctx.strokeRect(4, 4, 120, 120);
  // Corner rivets
  qctx.fillStyle = 'rgba(60,30,5,0.8)';
  for (const [rx, ry] of [[16, 16], [112, 16], [16, 112], [112, 112]]) {
    qctx.beginPath(); qctx.arc(rx, ry, 5, 0, Math.PI * 2); qctx.fill();
  }
  qctx.fillStyle = '#fff7e8';
  qctx.strokeStyle = 'rgba(60,30,5,0.85)';
  qctx.lineWidth = 6;
  qctx.font = '900 84px Arial';
  qctx.textAlign = 'center';
  qctx.textBaseline = 'middle';
  qctx.strokeText('?', 64, 70);
  qctx.fillText('?', 64, 70);
  const decalTex = new THREE.CanvasTexture(qCanvas);
  decalTex.anisotropy = 4;

  // Soft radial glow sprite (additive, replaces PointLights)
  const gCanvas = document.createElement('canvas');
  gCanvas.width = gCanvas.height = 128;
  const gctx = gCanvas.getContext('2d');
  const rg = gctx.createRadialGradient(64, 64, 4, 64, 64, 64);
  rg.addColorStop(0, 'rgba(255,190,90,0.55)');
  rg.addColorStop(0.4, 'rgba(255,150,50,0.22)');
  rg.addColorStop(1, 'rgba(255,120,30,0)');
  gctx.fillStyle = rg;
  gctx.fillRect(0, 0, 128, 128);
  const glowTex = new THREE.CanvasTexture(gCanvas);

  _shared = {
    decalTex,
    glowTex,
    boxGeo: new THREE.BoxGeometry(1.3, 1.3, 1.3),
    lidGeo: new THREE.BoxGeometry(1.36, 0.18, 1.36),
    decalGeo: new THREE.PlaneGeometry(1.05, 1.05),
    glowGeo: new THREE.PlaneGeometry(3.6, 3.6),
    boxMat: new THREE.MeshPhongMaterial({
      color: 0xffa832, emissive: 0x7a4a00, emissiveIntensity: 0.55,
      shininess: 90, specular: 0xffeecc,
    }),
    lidMat: new THREE.MeshPhongMaterial({
      color: 0x8a5a18, emissive: 0x3a2404, emissiveIntensity: 0.4,
      shininess: 60,
    }),
    glowMat: new THREE.MeshBasicMaterial({
      map: glowTex, transparent: true, depthWrite: false,
      blending: THREE.AdditiveBlending, side: THREE.DoubleSide,
    }),
  };
  return _shared;
}

// ═══════════════════════════════════════════════════════
//  createItemBoxes(scene) — place decorative boxes along the
//  track, alternating sides, just beyond the curb so they
//  never interfere with racing. Returns an array of boxes
//  whose userData carries animation state.
// ═══════════════════════════════════════════════════════
export function createItemBoxes(scene) {
  const S = getShared();
  const boxes = [];
  const COUNT = 10;

  for (let i = 0; i < COUNT; i++) {
    const t = (i + 0.5) / COUNT; // offset from start line & sector marks
    const { point, side } = frame(t);
    const sideSign = i % 2 === 0 ? 1 : -1;
    const lateral = sideSign * (TRACK_WIDTH / 2 + CURB_W + 2.2);

    const box = new THREE.Group();

    const body = new THREE.Mesh(S.boxGeo, S.boxMat);
    body.castShadow = true;
    box.add(body);

    // Lid seams top & bottom give the cube a "crate" read
    for (const y of [0.62, -0.62]) {
      const lid = new THREE.Mesh(S.lidGeo, S.lidMat);
      lid.position.y = y;
      box.add(lid);
    }

    // "?" decals on the four vertical faces
    const decalMat = new THREE.MeshBasicMaterial({ map: S.decalTex, transparent: true });
    for (const [pos, rotY] of [
      [[0, 0, 0.66], 0], [[0, 0, -0.66], Math.PI],
      [[0.66, 0, 0], Math.PI / 2], [[-0.66, 0, 0], -Math.PI / 2],
    ]) {
      const q = new THREE.Mesh(S.decalGeo, decalMat);
      q.position.set(...pos);
      q.rotation.y = rotY;
      box.add(q);
    }

    // Additive glow halo (billboarded cheaply by facing up-track)
    const glow = new THREE.Mesh(S.glowGeo, S.glowMat);
    glow.renderOrder = 5;
    box.add(glow);
    box.userData.glow = glow;

    box.position.set(point.x + side.x * lateral, 1.7, point.z + side.z * lateral);
    box.userData.baseY = 1.7;
    box.userData.phase = i * 1.37;      // desync bobbing
    box.userData.spinRate = 0.6 + (i % 3) * 0.25;
    scene.add(box);
    boxes.push(box);
  }
  return boxes;
}

// ═══════════════════════════════════════════════════════
//  updateItemBoxes(boxes, elapsed, camera) — bob, spin, pulse.
//  Call once per frame from the game loop. Cheap: no allocs.
// ═══════════════════════════════════════════════════════
export function updateItemBoxes(boxes, elapsed, camera) {
  if (!boxes.length) return;
  // Pulse the shared box material once (all boxes pulse together)
  const S = getShared();
  S.boxMat.emissiveIntensity = 0.45 + 0.25 * Math.sin(elapsed * 2.2);
  for (const box of boxes) {
    const ph = box.userData.phase;
    box.position.y = box.userData.baseY + Math.sin(elapsed * 1.6 + ph) * 0.25;
    box.rotation.y = elapsed * box.userData.spinRate + ph;
    // Billboard the glow halo toward the camera when available
    if (camera && box.userData.glow) box.userData.glow.lookAt(camera.position);
  }
}