import * as I from 'immutable';

import {arrayUnique, compose, EventEmitter, flatten} from '@avocado/core';

import {Layer} from './layer';
import LayersUpdateLayerPacket from './packets/layers-update-layer.packet';

const decorate = compose(
  EventEmitter,
);

export class Layers extends decorate(class {}) {

  constructor(json) {
    super();
    this.layers = [];
    if ('undefined' !== typeof json) {
      this.fromJSON(json);
    }
  }

  *[Symbol.iterator]() {
    for (let i = 0; i < this.layers.length; i++) {
      yield {
        index: i,
        layer: this.layers[i],
      };
    }
  }

  acceptPacket(packet) {
    if (packet instanceof LayersUpdateLayerPacket) {
      for (let i = 0; i < packet.data.length; i++) {
        const {layerIndex, layerPackets} = packet.data[i];
        for (let j = 0; j < layerPackets.length; j++) {
          this.layers[layerIndex].acceptPacket(layerPackets[j]);
        }
      }
    }
  }

  addEntityToLayer(entity, layerIndex) {
    const layer = this.layers[layerIndex];
    if (!layer) {
      return;
    }
    layer.addEntity(entity);
  }

  addLayer(layer) {
    layer.on('entityAdded', this.onEntityAddedToLayers, this);
    layer.on('entityRemoved', this.onEntityRemovedFromLayers, this);
    this.layers.push(layer);
    layer.index = this.layers.length - 1;
    this.emit('layerAdded', layer);
  }

  allEntities() {
    let allEntities = [];
    for (let i = 0; i < this.layers.length; i++) {
      const layerEntities = this.layers[i].allEntities();
      for (let j = 0; j < layerEntities.length; j++) {
        allEntities.push(layerEntities[j]);
      }
    }
    return allEntities;
  }

  cleanPackets() {
    for (let i = 0; i < this.layers.length; i++) {
      this.layers[i].cleanPackets();
    }
  }

  destroy() {
    for (let i = 0; i < this.layers.length; i++) {
      const layer = this.layers[i];
      this.removeLayer(layer);
      layer.destroy();
    }
  }

  findEntity(uuid) {
    for (let i = 0; i < this.layers.length; i++) {
      const foundEntity = this.layers[i].findEntity(uuid);
      if (foundEntity) {
        return foundEntity;
      }
    }
  }

  fromJSON(json) {
    for (let i = 0; i < json.length; i++) {
      this.addLayer(new Layer(json[i]));
    }
    return this;
  }

  layer(index) {
    return this.layers[index];
  }

  onEntityAddedToLayers(entity) {
    this.emit('entityAdded', entity);
  }

  onEntityRemovedFromLayers(entity) {
    this.emit('entityRemoved', entity);
  }

  packets(informed) {
    const packets = [];
    const updates = [];
    for (let i = 0; i < this.layers.length; i++) {
      const layerPackets = this.layers[i].packets(informed);
      if (0 === layerPackets.length) {
        continue;
      }
      updates.push({
        layerIndex: i,
        layerPackets,
      });
    }
    if (updates.length > 0) {
      packets.push(new LayersUpdateLayerPacket(updates));
    }
    return packets;
  }

  removeEntityFromLayer(entity, layerIndex) {
    const layer = this.layers[layerIndex];
    if (!layer) {
      return;
    }
    layer.removeEntity(entity);
  }

  // TODO: fix index for remaining layers
  removeLayer(layer) {
    const index = this.layers.indexOf(layer);
    if (-1 === index) {
      return;
    }
    layer.off('entityAdded', this.onEntityAddedToLayers);
    layer.off('entityRemoved', this.onEntityRemovedFromLayers);
    this.layers.splice(index, 1);
    this.emit('layerRemoved', layer);
  }

  tick(elapsed) {
    for (let i = 0; i < this.layers.length; i++) {
      this.layers[i].tick(elapsed);
    }
  }

  toJSON() {
    return this.layers.map((layer) => layer.toJSON());
  }

  toNetwork(informed) {
    return this.layers.map((layer) => layer.toNetwork(informed));
  }

  visibleEntities(query) {
    const entities = [];
    for (let i = 0; i < this.layers.length; i++) {
      const layerVisibleEntities = this.layers[i].visibleEntities(query);
      for (let j = 0; j < layerVisibleEntities.length; j++) {
        const layerVisibleEntity = layerVisibleEntities[j];
        entities.push(layerVisibleEntity);
      }
    }
    return entities;
  }

}