import * as THREE from 'three';
import { getMaxPixelRatio, getQualityTier } from './quality.js';

let scene, camera, renderer;
const _worldObjects = [];

/**
 * @param {HTMLCanvasElement|null} existingCanvas — pass the saved canvas on
 * re-init so Three.js reuses the same DOM element instead of creating a new one
 */
export function initWorld(existingCanvas) {
  scene = new THREE.Scene();
  scene.background = new THREE.Color(0x000000);
  scene.fog = new THREE.FogExp2(0x000000, 0.035);

  camera = new THREE.PerspectiveCamera(60, window.innerWidth / window.innerHeight, 0.1, 500);
  camera.position.set(0, 12, 28);
  camera.lookAt(0, 0, 0);

  const tier = getQualityTier();
  renderer = new THREE.WebGLRenderer({
    antialias: tier !== 'low',
    canvas: existingCanvas || undefined,
  });
  renderer.setSize(window.innerWidth, window.innerHeight);
  renderer.setPixelRatio(Math.min(window.devicePixelRatio, getMaxPixelRatio()));
  renderer.outputColorSpace = THREE.SRGBColorSpace;

  if (!existingCanvas) {
    document.body.prepend(renderer.domElement);
  }

  addLights(scene);
  addGrid(scene, tier);

  return { scene, camera, renderer };
}

function addLights(scene) {
  const ambient = new THREE.AmbientLight(0x001a00, 0.6);
  scene.add(ambient);

  const point = new THREE.PointLight(0x00ff41, 2, 80);
  point.position.set(0, 20, 0);
  scene.add(point);

  const fill = new THREE.DirectionalLight(0x003300, 0.4);
  fill.position.set(-10, 10, 10);
  scene.add(fill);
}

function addGrid(scene, tier) {
  const gridDivisions = tier === 'low' ? 20 : 40;
  const grid = new THREE.GridHelper(100, gridDivisions, 0x003300, 0x001a00);
  grid.position.y = -0.01;
  scene.add(grid);
  _worldObjects.push(grid);

  const planeGeo = new THREE.PlaneGeometry(100, 100);
  const planeMat = new THREE.MeshBasicMaterial({
    color: 0x000a00,
    transparent: true,
    opacity: 0.5,
  });
  const plane = new THREE.Mesh(planeGeo, planeMat);
  plane.rotation.x = -Math.PI / 2;
  plane.position.y = -0.02;
  scene.add(plane);
  _worldObjects.push(plane);
}

/**
 * Dispose only world-owned geometries, materials, and the renderer.
 * Agent and effect objects are disposed by their own modules before this runs.
 */
export function disposeWorld(disposeRenderer, _scene) {
  for (const obj of _worldObjects) {
    if (obj.geometry) obj.geometry.dispose();
    if (obj.material) {
      const mats = Array.isArray(obj.material) ? obj.material : [obj.material];
      mats.forEach(m => {
        if (m.map) m.map.dispose();
        m.dispose();
      });
    }
  }
  _worldObjects.length = 0;
  disposeRenderer.dispose();
}

export function onWindowResize(camera, renderer) {
  camera.aspect = window.innerWidth / window.innerHeight;
  camera.updateProjectionMatrix();
  renderer.setSize(window.innerWidth, window.innerHeight);
}