import {compose, EventEmitter, Property} from '@avocado/core';
import {hasGraphics, Image} from '@avocado/graphics';
import {Rectangle, Vector} from '@avocado/math';
import {shapeFromJSON} from '@avocado/physics';
import {Resource} from '@avocado/resource';

const decorate = compose(
  EventEmitter,
  Property('image', {
    track: true,
  }),
  Vector.Mixin('tileSize', 'tileWidth', 'tileHeight', {
    default: [0, 0],
  }),
);

export class Tileset extends decorate(Resource) {

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

  destroy() {
    this.subimages.forEach((subimage) => {
      subimage.destroy();
    });
    this.subimages = [];
  }

  fromJSON(json) {
    let promise;
    if (json.geometry) {
      for (const i in json.geometry) {
        const shapeJSON = json.geometry[i];
        this._geometry[i] = shapeFromJSON(shapeJSON);
      }
    }
    if (json.tileSize) {
      this.tileSize = json.tileSize;
    }
    if (hasGraphics && json.imageUri) {
      Image.load(json.imageUri).then((image) => {
        this.image = image;
      });
    }
  }

  geometry(index) {
    return this._geometry[index];
  }

  get image() {
    return super.image;
  }

  set image(image) {
    this.recalculateSubimages(image);
    super.image = image;
  }

  recalculateSubimages(image) {
    if (!image) {
      return;
    }
    const tileSize = this.tileSize;
    if (Vector.isZero(tileSize)) {
      return;
    }
    this.destroy();
    const grid = Vector.div(image.size, tileSize);
    const rectangle = Rectangle.compose([0, 0], tileSize);
    for (let j = 0; j < grid[1]; ++j) {
      for (let i = 0; i < grid[0]; ++i) {
        const subimage = image.subimage(rectangle);
        this.subimages.push(subimage);
        rectangle[0] += tileSize[0];
      }
      rectangle[0] = 0;
      rectangle[1] += tileSize[1];
    }
  }

  subimage(index) {
    return this.subimages[index];
  }

  get tileSize() {
    return super.tileSize;
  }

  set tileSize(tileSize) {
    super.tileSize = tileSize;
    this.recalculateSubimages(this.image);
  }

  toJSON() {
    return {
      tileSize: this.tileSize,
      imageUri: this.image.uri,
    }
  }

}