<?php
/**
 * Created by IntelliJ IDEA.
 * User: philippe-adrien
 * Date: 2019-01-19
 * Time: 12:27
 */

namespace OCA\TestNextcloudApp\Controller;

/**
 * Converts an ANSI text to HTML5.
 */
class AnsiToHtmlConverter
{
  protected $charset;
  protected $inlineStyles;
  protected $inlineColors;
  protected $colorNames;
  public function __construct($inlineStyles = true, $charset = 'UTF-8')
  {
    $this->inlineStyles = $inlineStyles;
    $this->charset = $charset;
    $this->colorNames = array(
      'black', 'red', 'green', 'yellow', 'blue', 'magenta', 'cyan', 'white',
      '', '',
      'brblack', 'brred', 'brgreen', 'bryellow', 'brblue', 'brmagenta', 'brcyan', 'brwhite',
    );
  }
  public function convert($text)
  {
    // remove cursor movement sequences
    $text = preg_replace('#\e\[(K|s|u|2J|2K|\d+(A|B|C|D|E|F|G|J|K|S|T)|\d+;\d+(H|f))#', '', $text);
    // remove character set sequences
    $text = preg_replace('#\e(\(|\))(A|B|[0-2])#', '', $text);
    $text = htmlspecialchars($text, PHP_VERSION_ID >= 50400 ? ENT_QUOTES | ENT_SUBSTITUTE : ENT_QUOTES, $this->charset);
    // carriage return
    $text = preg_replace('#^.*\r(?!\n)#m', '', $text);
    $tokens = $this->tokenize($text);
    // a backspace remove the previous character but only from a text token
    foreach ($tokens as $i => $token) {
      if ('backspace' == $token[0]) {
        $j = $i;
        while (--$j >= 0) {
          if ('text' == $tokens[$j][0] && strlen($tokens[$j][1]) > 0) {
            $tokens[$j][1] = substr($tokens[$j][1], 0, -1);
            break;
          }
        }
      }
    }
    $html = '';
    foreach ($tokens as $token) {
      if ('text' == $token[0]) {
        $html .= $token[1];
      } elseif ('color' == $token[0]) {
        $html .= $this->convertAnsiToColor($token[1]);
      }
    }
    if ($this->inlineStyles) {
      $html = sprintf('<span style="background-color: %s; color: %s">%s</span>', $this->inlineColors['black'], $this->inlineColors['white'], $html);
    } else {
      $html = sprintf('<span class="ansi_color_bg_black ansi_color_fg_white">%s</span>', $html);
    }
    // remove empty span
    $html = preg_replace('#<span[^>]*></span>#', '', $html);
    return $html;
  }

  protected function convertAnsiToColor($ansi)
  {
    $bg = 0;
    $fg = 7;
    $as = '';
    if ('0' != $ansi && '' != $ansi) {
      $options = explode(';', $ansi);
      foreach ($options as $option) {
        if ($option >= 30 && $option < 38) {
          $fg = $option - 30;
        } elseif ($option >= 40 && $option < 48) {
          $bg = $option - 40;
        } elseif (39 == $option) {
          $fg = 7;
        } elseif (49 == $option) {
          $bg = 0;
        }
      }
      // options: bold => 1, underscore => 4, blink => 5, reverse => 7, conceal => 8
      if (in_array(1, $options)) {
        $fg += 10;
        $bg += 10;
      }
      if (in_array(4, $options)) {
        $as = '; text-decoration: underline';
      }
      if (in_array(7, $options)) {
        $tmp = $fg;
        $fg = $bg;
        $bg = $tmp;
      }
    }
    if ($this->inlineStyles) {
      return sprintf('</span><span style="background-color: %s; color: %s%s">', $this->inlineColors[$this->colorNames[$bg]], $this->inlineColors[$this->colorNames[$fg]], $as);
    } else {
      return sprintf('</span><span class="ansi_color_bg_%s ansi_color_fg_%s">', $this->colorNames[$bg], $this->colorNames[$fg]);
    }
  }
  protected function tokenize($text)
  {
    $tokens = array();
    preg_match_all("/(?:\e\[(.*?)m|(\x08))/", $text, $matches, PREG_OFFSET_CAPTURE);
    $offset = 0;
    foreach ($matches[0] as $i => $match) {
      if ($match[1] - $offset > 0) {
        $tokens[] = array('text', substr($text, $offset, $match[1] - $offset));
      }
      $tokens[] = array("\x08" == $match[0] ? 'backspace' : 'color', $matches[1][$i][0]);
      $offset = $match[1] + strlen($match[0]);
    }
    if ($offset < strlen($text)) {
      $tokens[] = array('text', substr($text, $offset));
    }
    return $tokens;
  }
}