import * as I from 'immutable';

import {compose} from '@avocado/core';
import {StateProperty, Trait} from '@avocado/entity';
import {Rectangle, Vector} from '@avocado/math';
import {Property} from '@avocado/mixins';

import {Container} from '../container';
import {hasGraphics} from '../has-graphics';

const AUTO_ZINDEX = 1 << 16;

const decorate = compose(
  StateProperty('isVisible', {
    track: true,
  }),
  Property('visibleBoundingBox', {
    default: [0, 0, 0, 0],
    emit: function (...args) {
      this.entity.emit(...args);
    },
    track: true,
  }),
  StateProperty('opacity', {
    track: true,
  }),
  StateProperty('visibleScale', {
    track: true,
  }),
  StateProperty('zIndex', {
    track: true,
  }),
);

export class Visible extends decorate(Trait) {

  static defaultParams() {
    return {
      trackPosition: true,
    };
  }

  static defaultState() {
    return {
      isVisible: true,
      opacity: 1,
      visibleScale: [1, 1],
      zIndex: AUTO_ZINDEX,
    };
  }

  initialize() {
    if (hasGraphics) {
      this._container = new Container();
      this._container.isVisible = this.entity.isVisible;
    }
    this.scheduledBoundingBoxUpdate = true;
    this.trackPosition = this.params.get('trackPosition');
    this.onZIndexChanged();
  }

  destroy() {
    if (this._container) {
      this._container.destroy();
    }
  }

  get container() {
    return this._container;
  }

  onZIndexChanged() {
    const zIndex = this.entity.zIndex;
    this._usingAutoZIndex = AUTO_ZINDEX === zIndex;
    if (!this._usingAutoZIndex) {
      if (this._container) {
        this._container.zIndex = zIndex;
      }
    }
  }

  get rawVisibleScale() {
    const scale = this.entity.visibleScale;
    return [scale.get(0), scale.get(1)];
  }

  set rawVisibleScale(scale) {
    this.entity.visibleScale = I.List(scale);
  }

  shouldSynchronizePosition() {
    if (!this._container) {
      return false;
    }
    return this._container && this.trackPosition;
  }

  synchronizePosition() {
    if (!this.entity.is('positioned')) {
      return;
    }
    if (!this._container) {
      return;
    }
    this._container.position = this.entity.position;
    if (this._usingAutoZIndex) {
      if (this._container) {
        this._container.zIndex = this.entity.y;
      }
    }
  }

  get visibleScaleX() {
    return this.entity.visibleScale.get(0);
  }

  set visibleScaleX(x) {
    this.rawVisibleScale = [x, this.visibleScaleY];
  }

  get visibleScaleY() {
    return this.entity.visibleScale.get(1);
  }

  set visibleScaleY(y) {
    this.rawVisibleScale = [this.visibleScaleX, y];
  }

  listeners() {
    const listeners = {

      isVisibleChanged: () => {
        if (!this._container) {
          return;
        }
        this._container.visible = this.entity.isVisible;
      },

      opacityChanged: () => {
        if (!this._container) {
          return;
        }
        this._container.alpha = this.entity.opacity;
      },

      positionChanged: () => {
        this.scheduledBoundingBoxUpdate = true;
      },

      zIndexChanged: () => {
        this.onZIndexChanged();
      },

    };
    if (this.shouldSynchronizePosition()) {
      listeners.traitAdded = (type) => {
        if (-1 === [
          'visible',
          'positioned',
        ].indexOf(type)) {
          return;
        }
        this.synchronizePosition();
      };
    }
    return listeners;
  }

  methods() {
    return {

      updateVisibleBoundingBox: () => {
        this.scheduledBoundingBoxUpdate = true;
      },

    }
  }

  tick(elapsed) {
    if (this.shouldSynchronizePosition()) {
      this.synchronizePosition();
    }
    if (this.scheduledBoundingBoxUpdate) {
      // Collect all bounding boxes.
      const visibleBoundingBoxes = this.entity.invokeHookFlat(
        'visibleBoundingBoxes'
      );
      if (0 === visibleBoundingBoxes.length) {
        this.visibleBoundingBox = [0, 0, 0, 0];
      }
      else {
        let unifiedBoundingBox = [0, 0, 0, 0];
        for (let i = 0; i < visibleBoundingBoxes.length; ++i) {
          const visibleBoundingBox = visibleBoundingBoxes[i];
          unifiedBoundingBox = Rectangle.united(
            unifiedBoundingBox,
            visibleBoundingBox,
          );
        }
        this.visibleBoundingBox = unifiedBoundingBox;
        this.scheduledBoundingBoxUpdate = false;
      }
    }
  }

}