import * as THREE from "three";
import type { Selectable, SystemVisual } from "./viewerTypes";

/**
 * Galaxy rendering layer — the galaxy map.
 * Scene coordinate unit: display-unit (light-year scale).
 * Only visible in galaxy POV, rendered on top of the universe backdrop.
 * Contains star dots and shell reticles for each system.
 */
export class GalaxyLayer {
  readonly scene = new THREE.Scene();
  readonly camera = new THREE.PerspectiveCamera(50, 1, 0.1, 600000);

  /** Star dots and shell reticles, one per system. */
  readonly systemGroup = new THREE.Group();

  readonly selectableTargets = new Map<THREE.Object3D, Selectable>();
  readonly systemVisuals = new Map<string, SystemVisual>();

  constructor() {
    this.scene.fog = new THREE.FogExp2(0x040912, 0.000035);
    this.scene.add(new THREE.AmbientLight(0x90a6c0, 0.55));
    const keyLight = new THREE.DirectionalLight(0xdcecff, 1.3);
    keyLight.position.set(1000, 1200, 800);
    this.scene.add(keyLight);
    this.scene.add(this.systemGroup);
  }

  updateCamera(focus: THREE.Vector3, orbitOffset: THREE.Vector3) {
    this.camera.position.copy(focus).add(orbitOffset);
    this.camera.lookAt(focus);
  }

  onResize(aspect: number) {
    this.camera.aspect = aspect;
    this.camera.updateProjectionMatrix();
  }

  render(renderer: THREE.WebGLRenderer) {
    renderer.render(this.scene, this.camera);
  }
}