/*
 * noVNC: HTML5 VNC client
 * Copyright (C) 2019 The noVNC Authors
 * Licensed under MPL 2.0 (see LICENSE.txt)
 *
 * See README.md for usage and integration instructions.
 *
 */

export default class RawDecoder {
  constructor() {
    this._lines = 0;
  }

  decodeRect(x, y, width, height, sock, display, depth) {
    if (width === 0 || height === 0) {
      return true;
    }

    if (this._lines === 0) {
      this._lines = height;
    }

    const pixelSize = depth == 8 ? 1 : 4;
    const bytesPerLine = width * pixelSize;

    if (sock.rQwait('RAW', bytesPerLine)) {
      return false;
    }

    const curY = y + (height - this._lines);
    const currHeight = Math.min(this._lines, Math.floor(sock.rQlen / bytesPerLine));
    const pixels = width * currHeight;

    let data = sock.rQ;
    let index = sock.rQi;

    // Convert data if needed
    if (depth == 8) {
      const newdata = new Uint8Array(pixels * 4);
      for (let i = 0; i < pixels; i++) {
        newdata[i * 4 + 0] = (((data[index + i] >> 0) & 0x3) * 255) / 3;
        newdata[i * 4 + 1] = (((data[index + i] >> 2) & 0x3) * 255) / 3;
        newdata[i * 4 + 2] = (((data[index + i] >> 4) & 0x3) * 255) / 3;
        newdata[i * 4 + 3] = 255;
      }
      data = newdata;
      index = 0;
    }

    // Max sure the image is fully opaque
    for (let i = 0; i < pixels; i++) {
      data[index + i * 4 + 3] = 255;
    }

    display.blitImage(x, curY, width, currHeight, data, index);
    sock.rQskipBytes(currHeight * bytesPerLine);
    this._lines -= currHeight;
    if (this._lines > 0) {
      return false;
    }

    return true;
  }
}
