import { initWorld, onWindowResize, disposeWorld } from './world.js';
import {
  initAgents, updateAgents, getAgentCount,
  disposeAgents, getAgentStates, applyAgentStates,
} from './agents.js';
import { initEffects, updateEffects, disposeEffects } from './effects.js';
import { initUI, updateUI } from './ui.js';
import { initInteraction, updateControls, disposeInteraction } from './interaction.js';
import { initWebSocket, getConnectionState, getJobCount } from './websocket.js';
import { initVisitor } from './visitor.js';
import { initActivityFeed } from './activity-feed.js';

let running = false;
let canvas  = null;

/**
 * Build (or rebuild) the Three.js world.
 *
 * @param {boolean} firstInit
 *   true  — first page load: also starts UI, WebSocket, and visitor
 *   false — context-restore reinit: skips UI/WS (they survive context loss)
 * @param {Object.<string,string>|null} stateSnapshot
 *   Agent state map captured just before teardown; reapplied after initAgents.
 */
function buildWorld(firstInit, stateSnapshot) {
  const { scene, camera, renderer } = initWorld(canvas);
  canvas = renderer.domElement;

  initEffects(scene);
  initAgents(scene);

  if (stateSnapshot) {
    applyAgentStates(stateSnapshot);
  }

  initInteraction(camera, renderer);

  if (firstInit) {
    initUI();
    initWebSocket(scene);
    initVisitor();
    initActivityFeed();

    // Activity feed collapse/expand toggle
    const $feedPanel  = document.getElementById('activity-feed');
    const $feedClose  = document.getElementById('activity-feed-close');
    const $feedToggle = document.getElementById('activity-feed-toggle');
    if ($feedClose && $feedPanel) {
      $feedClose.addEventListener('click', () => $feedPanel.classList.add('collapsed'));
    }
    if ($feedToggle && $feedPanel) {
      $feedToggle.addEventListener('click', () => $feedPanel.classList.remove('collapsed'));
    }

    // Dismiss loading screen
    const loadingScreen = document.getElementById('loading-screen');
    if (loadingScreen) loadingScreen.classList.add('hidden');
  }

  // Debounce resize to 1 call per frame
  const ac = new AbortController();
  let resizeFrame = null;
  window.addEventListener('resize', () => {
    if (resizeFrame) cancelAnimationFrame(resizeFrame);
    resizeFrame = requestAnimationFrame(() => onWindowResize(camera, renderer));
  }, { signal: ac.signal });

  let frameCount  = 0;
  let lastFpsTime = performance.now();
  let currentFps  = 0;
  let rafId       = null;

  running = true;

  function animate() {
    if (!running) return;
    rafId = requestAnimationFrame(animate);

    const now = performance.now();
    frameCount++;
    if (now - lastFpsTime >= 1000) {
      currentFps  = Math.round(frameCount * 1000 / (now - lastFpsTime));
      frameCount  = 0;
      lastFpsTime = now;
    }

    updateControls();
    updateEffects(now);
    updateAgents(now);
    updateUI({
      fps: currentFps,
      agentCount: getAgentCount(),
      jobCount: getJobCount(),
      connectionState: getConnectionState(),
    });

    renderer.render(scene, camera);
  }

  // Pause rendering when tab is backgrounded (saves battery on iPad PWA)
  document.addEventListener('visibilitychange', () => {
    if (document.hidden) {
      if (rafId) {
        cancelAnimationFrame(rafId);
        rafId = null;
        running = false;
      }
    } else {
      if (!running) {
        running = true;
        animate();
      }
    }
  });

  animate();

  return { scene, renderer, ac };
}

function teardown({ scene, renderer, ac }) {
  running = false;
  ac.abort();
  disposeInteraction();
  disposeEffects();
  disposeAgents();
  disposeWorld(renderer, scene);
}

function main() {
  const $overlay = document.getElementById('webgl-recovery-overlay');

  let handle = buildWorld(true, null);

  // WebGL context loss recovery (iPad PWA, GPU driver reset, etc.)
  canvas.addEventListener('webglcontextlost', event => {
    event.preventDefault();
    running = false;
    if ($overlay) $overlay.style.display = 'flex';
  });

  canvas.addEventListener('webglcontextrestored', () => {
    const snapshot = getAgentStates();
    teardown(handle);
    handle = buildWorld(false, snapshot);
    if ($overlay) $overlay.style.display = 'none';
  });
}

main();

// Register service worker only in production builds
if (import.meta.env.PROD && 'serviceWorker' in navigator) {
  navigator.serviceWorker.register('/sw.js').catch(() => {});
}