import * as I from 'immutable';

import {compose} from '@avocado/core';
import {create as createEntity, EntityList} from '@avocado/entity';
import {EventEmitter, Property} from '@avocado/mixins';
import {Synchronized} from '@avocado/state';

import {Tiles} from './tiles';

const decorate = compose(
  EventEmitter,
  Property('tilesetUri', {
    track: true,
  }),
);

export class Layer extends decorate(Synchronized) {

  constructor() {
    super();
    this.entityList = new EntityList();
    this.tiles = new Tiles();
    // Listeners.
    this.onEntityAddedToLayer = this.onEntityAddedToLayer.bind(this);
    this.onEntityRemovedFromLayer = this.onEntityRemovedFromLayer.bind(this);
    this.entityList.on('entityAdded', this.onEntityAddedToLayer);
    this.entityList.on('entityRemoved', this.onEntityRemovedFromLayer);
    this.onTileDataChanged = this.onTileDataChanged.bind(this);
    this.tiles.on('dataChanged', this.onTileDataChanged);
  }

  addEntity(entity) {
    this.entityList.addEntity(entity);
  }

  destroy() {
    this.entityList.destroy();
    this.entityList.off('entityAdded', this.onEntityAddedToLayer);
    this.entityList.off('entityRemoved', this.onEntityRemovedFromLayer);
  }

  findEntity(uuid) {
    return this.entityList.findEntity(uuid);
  }

  fromJSON(json) {
    if (json.entities) {
      json.entities.forEach((entityJSON) => {
        const entity = createEntity();
        this.entityList.addEntity(entity.fromJSON(entityJSON));
      });
    }
    if (json.tiles) {
      this.tiles.fromJSON(json.tiles)
    }
    if (json.tilesetUri) {
      this.tilesetUri = json.tilesetUri;
    }
    return this;
  }

  onEntityAddedToLayer(entity) {
    entity.addTrait('layered');
    entity.layer = this;
    this.emit('entityAdded', entity)
  }

  onEntityRemovedFromLayer(entity) {
    if (entity.is('layered')) {
      entity.removeTrait('layered');
    }
    this.emit('entityRemoved', entity);
  }

  onTileDataChanged() {
    this.emit('tileDataChanged');
  }

  removeEntity(entity) {
    this.entityList.removeEntity(entity);
  }

  setTileAt(x, y, tile) {
    this.tiles.setTileAt(x, y, tile);
  }

  synchronizedChildren() {
    return [
      'entityList',
      'tiles',
      'tilesetUri',
    ];
  }

  visibleEntities(query) {
    return this.entityList.visibleEntities(query);
  }

}