import BoundingRectangle from './BoundingRectangle.js'

export default class Bitmap {
  constructor(width, height, rgba = null) {
    this._w = width
    this._h = height
    this._com = 4 // number of components per pixel (RGBA)
    this._boundingRect = new BoundingRectangle(0, this._w - 1, 0, this._h - 1)
    const len = this._w * this._h * this._com
    this._data = new Uint8ClampedArray(len)

    if (rgba) {
      for (let i = 0; i < len; i += 4) {
        this._data[i] = rgba[0]
        this._data[i + 1] = rgba[1]
        this._data[i + 2] = rgba[2]
        this._data[i + 3] = rgba[3]
      }
    }

    // public
    this.width = this._w
    this.height = this._h
  }

  toImage() {
    const canvas = document.createElement('canvas');
    const ctx = canvas.getContext('2d');

    canvas.width = this._w;
    canvas.height = this._h;

    const imgData = ctx.createImageData(canvas.width, canvas.height);
    imgData.data.set(this._data);
    ctx.putImageData(imgData, 0, 0);

    return new Promise((resolve) => {

      const img = document.createElement('img')
      img.onload = () => {
        resolve(img)
      }
      img.src = canvas.toDataURL()
      return img
    })
  }

  getPix(x, y, out) {
    if (x < 0 || y < 0 || x >= this._w || y >= this._h) {
      return false
    }
    x = Math.round(x)
    y = Math.round(y)
    const idx = (y * 4 * this._w) + (x * 4)
    out[0] = this._data[idx]
    out[1] = this._data[idx + 1]
    out[2] = this._data[idx + 2]
    out[3] = this._data[idx + 3]
    return true
  }

  putPix(x, y, rgba) {
    if (x < 0 || y < 0 || x >= this._w || y >= this._h) {
      return
    }
    x = Math.round(x)
    y = Math.round(y)
    const idx = (y * this._com * this._w) + (x * this._com)
    this._data[idx] = rgba[0]
    this._data[idx + 1] = rgba[1]
    this._data[idx + 2] = rgba[2]
    this._data[idx + 3] = rgba[3]
  }

  getBoundingRect() {
    return this._boundingRect
  }
}