import * as THREE from 'three';
import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls.js';
import { CSS2DRenderer, CSS2DObject } from 'three/examples/jsm/renderers/CSS2DRenderer.js';

const BG_COLOR = 0x0f172a;
const GRID_COLOR = 0x334155; // slate-700
const RING_COLOR = 0x475569; // slate-600
const LABEL_COLOR = '#94a3b8'; // slate-400

export interface SceneContext {
  scene: THREE.Scene;
  camera: THREE.PerspectiveCamera;
  renderer: THREE.WebGLRenderer;
  labelRenderer: CSS2DRenderer;
  controls: OrbitControls;
  patternGroup: THREE.Group;
}

export function createScene(container: HTMLElement): SceneContext {
  const scene = new THREE.Scene();
  scene.background = new THREE.Color(BG_COLOR);

  // Camera
  const aspect = container.clientWidth / container.clientHeight;
  const camera = new THREE.PerspectiveCamera(55, aspect, 0.1, 100);
  camera.position.set(3, 2.5, 3);
  camera.lookAt(0, 0, 0);

  // WebGL renderer
  const renderer = new THREE.WebGLRenderer({ antialias: true });
  renderer.setPixelRatio(window.devicePixelRatio);
  renderer.setSize(container.clientWidth, container.clientHeight);
  container.appendChild(renderer.domElement);

  // CSS2D renderer for labels
  const labelRenderer = new CSS2DRenderer();
  labelRenderer.setSize(container.clientWidth, container.clientHeight);
  labelRenderer.domElement.style.position = 'absolute';
  labelRenderer.domElement.style.top = '0';
  labelRenderer.domElement.style.left = '0';
  labelRenderer.domElement.style.pointerEvents = 'none';
  container.appendChild(labelRenderer.domElement);

  // Orbit controls
  const controls = new OrbitControls(camera, renderer.domElement);
  controls.enableDamping = true;
  controls.dampingFactor = 0.08;
  controls.minDistance = 1.5;
  controls.maxDistance = 12;

  // Lighting
  const ambientLight = new THREE.AmbientLight(0xffffff, 0.4);
  scene.add(ambientLight);

  const dirLight = new THREE.DirectionalLight(0xffffff, 0.8);
  dirLight.position.set(5, 8, 5);
  scene.add(dirLight);

  const dirLight2 = new THREE.DirectionalLight(0xffffff, 0.3);
  dirLight2.position.set(-3, -2, -4);
  scene.add(dirLight2);

  // Grid on XZ plane
  const gridHelper = new THREE.GridHelper(6, 12, GRID_COLOR, GRID_COLOR);
  (gridHelper.material as THREE.Material).opacity = 0.3;
  (gridHelper.material as THREE.Material).transparent = true;
  scene.add(gridHelper);

  // Axis lines
  addAxisLines(scene);

  // Axis labels
  addAxisLabel(scene, 'X', new THREE.Vector3(3.3, 0, 0));
  addAxisLabel(scene, 'Y', new THREE.Vector3(0, 3.3, 0));
  addAxisLabel(scene, 'Z', new THREE.Vector3(0, 0, 3.3));

  // Reference dBi rings on XZ plane
  addReferenceRings(scene);

  // Group for pattern meshes
  const patternGroup = new THREE.Group();
  scene.add(patternGroup);

  // Resize handler
  const onResize = () => {
    const w = container.clientWidth;
    const h = container.clientHeight;
    camera.aspect = w / h;
    camera.updateProjectionMatrix();
    renderer.setSize(w, h);
    labelRenderer.setSize(w, h);
  };
  window.addEventListener('resize', onResize);

  // Animation loop
  const animate = () => {
    requestAnimationFrame(animate);
    controls.update();
    renderer.render(scene, camera);
    labelRenderer.render(scene, camera);
  };
  animate();

  return { scene, camera, renderer, labelRenderer, controls, patternGroup };
}

function addAxisLines(scene: THREE.Scene) {
  const len = 3.2;

  const xGeo = new THREE.BufferGeometry().setFromPoints([
    new THREE.Vector3(0, 0, 0),
    new THREE.Vector3(len, 0, 0),
  ]);
  const xMat = new THREE.LineBasicMaterial({ color: 0xef4444, opacity: 0.6, transparent: true });
  scene.add(new THREE.Line(xGeo, xMat));

  const yGeo = new THREE.BufferGeometry().setFromPoints([
    new THREE.Vector3(0, 0, 0),
    new THREE.Vector3(0, len, 0),
  ]);
  const yMat = new THREE.LineBasicMaterial({ color: 0x22c55e, opacity: 0.6, transparent: true });
  scene.add(new THREE.Line(yGeo, yMat));

  const zGeo = new THREE.BufferGeometry().setFromPoints([
    new THREE.Vector3(0, 0, 0),
    new THREE.Vector3(0, 0, len),
  ]);
  const zMat = new THREE.LineBasicMaterial({ color: 0x3b82f6, opacity: 0.6, transparent: true });
  scene.add(new THREE.Line(zGeo, zMat));
}

function addAxisLabel(scene: THREE.Scene, text: string, position: THREE.Vector3) {
  const el = document.createElement('span');
  el.textContent = text;
  el.style.color = LABEL_COLOR;
  el.style.fontFamily = "'Inter', sans-serif";
  el.style.fontSize = '12px';
  el.style.fontWeight = '600';
  const label = new CSS2DObject(el);
  label.position.copy(position);
  scene.add(label);
}

function addReferenceRings(scene: THREE.Scene) {
  const dbiLevels = [-3, 0, 3, 6];
  const minDbi = -3;
  const maxDbi = 6;

  dbiLevels.forEach((dbi) => {
    const normalized = (dbi - minDbi) / (maxDbi - minDbi);
    const radius = 0.1 + normalized * 1.9; // map to [0.1, 2.0]

    const curve = new THREE.EllipseCurve(0, 0, radius, radius, 0, 2 * Math.PI, false, 0);
    const points = curve.getPoints(64);
    const geo = new THREE.BufferGeometry().setFromPoints(
      points.map((p) => new THREE.Vector3(p.x, 0, p.y))
    );
    const mat = new THREE.LineBasicMaterial({
      color: RING_COLOR,
      opacity: 0.35,
      transparent: true,
    });
    const ring = new THREE.Line(geo, mat);
    scene.add(ring);

    // Label for the ring
    const el = document.createElement('span');
    el.textContent = `${dbi >= 0 ? '+' : ''}${dbi} dBi`;
    el.style.color = '#64748b'; // slate-500
    el.style.fontFamily = "'Inter', sans-serif";
    el.style.fontSize = '10px';
    const label = new CSS2DObject(el);
    label.position.set(radius + 0.1, 0, 0);
    scene.add(label);
  });
}