/**
 * energy-beam.js — Vertical energy beam above the Batcave terminal
 *
 * Category: DATA-TETHERED AESTHETIC
 * Data source: state.activeAgentCount (0 = faint, 3+ = full intensity)
 *
 * A glowing cyan cylinder rising from the Batcave area.
 * Intensity and pulse amplitude are driven by the number of active agents.
 */

import * as THREE from 'three';

const BEAM_RADIUS   = 0.2;
const BEAM_HEIGHT   = 50;
const BEAM_X        = -10;
const BEAM_Y        =  0;
const BEAM_Z        = -10;

let _state = null;
let _beamMaterial = null;
let _pulse = 0;

/**
 * @param {THREE.Scene} scene
 * @param {object} state  Shared state bus (reads state.activeAgentCount)
 * @param {object} theme  Theme bus (reads theme.colors.accent)
 */
export function init(scene, state, theme) {
  _state = state;

  const accentColor = theme?.colors?.accent ?? 0x4488ff;

  const geo = new THREE.CylinderGeometry(BEAM_RADIUS, BEAM_RADIUS * 2.5, BEAM_HEIGHT, 32, 16, true);
  _beamMaterial = new THREE.MeshBasicMaterial({
    color: accentColor,
    transparent: true,
    opacity: 0.6,
    blending: THREE.AdditiveBlending,
    side: THREE.DoubleSide,
    depthWrite: false,
  });
  const beam = new THREE.Mesh(geo, _beamMaterial);
  beam.position.set(BEAM_X, BEAM_Y + BEAM_HEIGHT / 2, BEAM_Z);
  scene.add(beam);
}

export function update(_elapsed, _delta) {
  if (!_beamMaterial) return;

  _pulse += 0.02;

  const agentCount = _state?.activeAgentCount ?? 0;
  const agentIntensity = agentCount === 0 ? 0.1 : Math.min(0.1 + agentCount * 0.3, 1.0);
  const pulseEffect = Math.sin(_pulse) * 0.15 * agentIntensity;
  _beamMaterial.opacity = agentIntensity * 0.6 + pulseEffect;
}