DWE.Image = {}

DWE.Image.Image = function (src) {
  this.src = src
  this.img = new Image()
  this.img.src = this.src

  this.width = 0
  this.height = 0

  this.loaded = false
  this.errored = false

  this.img.onload = () => {
    this.loaded = true
    this.width = this.img.width
    this.height = this.img.height

    if (this['onload']) {
      this.onload.apply(this, [])
    }
  }

  this.img.onerror = (e) => {
    this.loaded = false
    this.errored = true

    if (this['onerror']) {
      this.onerror.apply(this, [e])
    }
  }
}

DWE.Image.TileMap = class TileMap extends DWE.Image.Image {
  constructor (src, aspectWidth, aspectHeight) {
    super(src)
    this.aspectWidth = aspectWidth
    this.aspectHeight = aspectHeight
    this.tiles = []
  }

  onload () {
    for (let y = 0; y < this.height / this.aspectHeight; y++) {
      for (let x = 0; x < this.width / this.aspectWidth; x++) {
        this.tiles.push(new DWE.Math.Vector2(x, y))
      }
    }

    if (this['onready']) {
      this.onready.call(this, this)
    }
  }

  draw (ctx, index, x, y, w, h) {
    let box = this.tiles[index]
    if (!box) return
    ctx.drawImage(this.img, box.x * this.aspectWidth, box.y * this.aspectHeight, this.aspectWidth, this.aspectHeight, x, y, w, h)
  }
}

// Load an array of image URLs
// Returns a Promise
DWE.Image.loadImageArray = function (uris) {
  return new Promise(function (resolve, reject) {
    let loaded = 0
    let toLoad = uris.length
    let images = []

    function loadNext(index) {
      let uri = uris[index]
      let img = new DWE.Image.Image(uri)
      img.onload = function () {
        images.push(img)
        loaded++

        if (loaded == toLoad)
          resolve(images)
        else
          loadNext(loaded)
      }

      img.onerror = function (e) {
        reject(e)
      }
    }

    loadNext(loaded)
  })
}