import {compose} from '@avocado/core';
import {StateProperty, Trait} from '@avocado/entity';

const decorate = compose(
  StateProperty('isCheckingCollisions'),
);

export class Collider extends decorate(Trait) {

  static defaultParams() {
    return {
      collidesWithGroups: [
        'default',
      ],
      collisionGroup: 'default',
      isSensor: false,
    }
  }

  static defaultState() {
    return {
      isCheckingCollisions: true,
    }
  }

  initialize() {
    this._collisionGroup = this.params.get('collisionGroup');
    this._collidesWithGroups = this.params.get('collidesWithGroups').toJS();
    this._isCollidingWith = [];
    this._isSensor = this.params.get('isSensor');
  }

  destroy() {
    for (let i = 0; i < this._isCollidingWith.length; i++) {
      const entity = this._isCollidingWith[i];
      entity.emit('collisionEnd', this.entity);
    }
    this._isCollidingWith = [];
  }

  get collisionGroup() {
    return this._collisionGroup;
  }

  get collidesWithGroups() {
    return this._collidesWithGroups;
  }

  get isCollidingWith() {
    return this._isCollidingWith;
  }

  get isSensor() {
    return this._isSensor;
  }

  listeners() {
    return {

      collisionEnd: (other) => {
        const index = this._isCollidingWith.indexOf(other);
        if (-1 !== index) {
          this._isCollidingWith.splice(index, 1);
        }
      },

      collisionStart: (other) => {
        const index = this._isCollidingWith.indexOf(other);
        if (-1 === index) {
          this._isCollidingWith.push(other);
        }
      },

    };
  }

  methods() {
    return {

      collidesWith: (entity) => {
        const collisionGroup = entity.collisionGroup();
        return -1 !== this._collidesWithGroups.indexOf(collisionGroup);
      },

    };
  }
}