// Node.
import {performance} from 'perf_hooks';
// 3rd party.
import immutablediff from 'immutablediff';
// 2nd party.
import {StateSynchronizer} from '@avocado/state';
// 1st party.
import {WorldTime} from '../common/world-time';
import {createEntityForConnection} from './create-entity-for-connection';
import {createRoom} from './create-server-room';
// Create game.
export default function() {
  setInterval(createMainLoop(), 1000 / 80);
  return createConnectionListener();
}
// Create room.
const room = createRoom();
// Time :)
const worldTime = new WorldTime();
worldTime.hour = 10;
// Entity tracking.
const informables = [];
const stateSynchronizer = new StateSynchronizer({
  room,
  worldTime,
});
// Connection listener.
function createConnectionListener() {
  return (socket) => {
    // Create and track a new entity for the connection.
    const entity = createEntityForConnection(socket);
    // Track informables.
    informables.push(entity);
    entity.on('destroyed', () => {
      const index = informables.indexOf(entity);
      if (-1 !== index) {
        informables.splice(index, 1);
      }
    });
    // Add entity to room.
    room.addEntityToLayer(entity, 'everything');
    // Listen for events.
    socket.on('message', createMessageListener(socket));
    socket.on('disconnect', createDisconnectionListener(socket));
  }
}
// Handle incoming messages.
function createMessageListener(socket) {
  const {entity} = socket;
  return ({type, payload}) => {
    switch (type) {
      case 'input':
        entity.inputState = payload;
        break;
    }
  };
}
// Handle disconnection.
function createDisconnectionListener(socket) {
  const {entity} = socket;
  return () => {
    entity.destroy();
  };
}
// Main loop.
let lastTime = performance.now();
function createMainLoop() {
  return () => {
    const now = performance.now();
    const elapsed = (now - lastTime) / 1000;
    lastTime = now;
    // Tick synchronized.
    stateSynchronizer.tick(elapsed);
    // Inform entities of the new state.
    for (const entity of informables) {
      entity.inform(stateSynchronizer.state);
    }
  }
}