<?php

/**

 * Class for drawing progress bars in a vt100 console.

 * @author Dan Fuhry

 * @license Public domain

 */

class ProgressBar

{

  /**

   * Shell escape character.

   * @const string

   */

  const SHELL_ESCAPE = "\x1B";

  /**

   * Carriage return (0x0D)

   * @const string

   */

  const CARRIAGE_RETURN = "\r";

  /**

   * Colors of the foreground, background, foreground text, and background text, respectively

   * @var int

   * @var int

   * @var int

   * @var int

   */

  private $color_bar, $color_empty, $color_text, $color_emptytext;

  /**

   * Text to the left of the bar.

   * @var string

   */

  private $bar_left;

  /**

   * Text to the right of the bar.

   * @var string

   */

  private $bar_right;

  /**

   * Text in the middle of the bar.

   * @var string

   */

  private $bar_text;

  /**

   * The current location of the bar in %.

   * @var int

   */

  private $bar_pos = 0;

  /**

   * Position where the text should start.

   * @var int

   */

  private $text_pos = 0;

  /**

   * Width of the current terminal.

   * @var int

   */

  private $term_width = 80;

  /**

   * Width of the actual bar.

   * @var int

   */

  private $bar_width = 0;

  /**

   * State of the bar's color. Used to avoid echoing tons of color codes.

   * @var int

   */

  private $color_state = 0;

  /**

   * Color state constants

   * @const int

   * @const int

   * @const int

   * @const int

   * @const int

   */

  const COLOR_STATE_RESET = 0;

  const COLOR_STATE_FULL_HIDE = 1;

  const COLOR_STATE_FULL_SHOW = 2;

  const COLOR_STATE_EMPTY_HIDE = 3;

  const COLOR_STATE_EMPTY_SHOW = 4;

  /**

   * Constructor. All parameters are optional. Color choices are defined in color_to_code.

   * @param string $bar_left

   * @param string $bar_right

   * @param string $bar_text

   * @param string $color_bar

   * @param string $color_empty

   * @param string $color_text

   * @param string $color_emptytext

   */

  public function __construct($bar_left = '[', $bar_right = ']', $bar_text = '', $color_bar = 'red', $color_empty = 'black', $color_text = 'white', $color_emptytext = 'cyan')

  {

    $this->bar_left = $bar_left;

    $this->bar_right = $bar_right;

    $this->color_bar = $this->color_to_code($color_bar);

    $this->color_empty = $this->color_to_code($color_empty);

    $this->color_text = $this->color_to_code($color_text);

    $this->color_emptytext = $this->color_to_code($color_emptytext);

    if ( isset($_SERVER['COLUMNS']) )

    {

      $this->term_width = intval($_SERVER['COLUMNS']);

    }

    $this->bar_width = $this->term_width - strlen($this->bar_left) - strlen($this->bar_right);

    $this->update_text_quiet($bar_text);

  }

  /**

   * Updates the text on the progress bar and recalculates the position without redrawing.

   * @param string Text in the bar. If omitted, blanked.

   */

  public function update_text_quiet($bar_text = '')

  {

    $this->bar_text = strval($bar_text);

    if ( !empty($this->bar_text) )

    {

      $this->text_pos = round(( $this->bar_width / 2 ) - ( strlen($this->bar_text) / 2 ));

    }

  }

  /**

   * Updates the text on the progress bar, recalculates the position, and redraws.

   * @param string Text in the bar. If omitted, blanked.

   */

  function update_text($bar_text = '')

  {

    $this->update_text_quiet($bar_text);

    $this->set($this->bar_pos);

  }

  /**

   * Starts output of the bar.

   */

  function start()

  {

    echo self::CARRIAGE_RETURN;

    echo $this->bar_left;

  }

  /**

   * Closes the bar.

   */

  function end()

  {

    $this->set($this->bar_pos, $this->bar_width);

    echo "\n";

  }

  /**

   * Sets the position of the bar.

   * @param int Position in %. If a second parameter is set, this is treated as a numerator with the second parameter being the denominator and that is used to calculate position.

   * @param int Optional. Total number of units to allow fraction usage instead of percentage.

   */

  function set($pos, $max = 100)

  {

    // if our pos is higher than 100%, reduce it

    if ( $pos > $max )

      $pos = $max;

    // arithmetic one-liner

    // this is where we should stop showing the "full" color and instead use "empty"

    $bar_pos = round($this->bar_width * ( $pos / $max ));

    $this->bar_pos = 100 * ( $pos / $max );

    // reset the cursor

    echo self::CARRIAGE_RETURN . $this->bar_left;

    // print everything out

    for ( $i = 0; $i < $this->bar_width; $i++ )

    {

      $char = ' ';

      $hide = true;

      if ( !empty($this->bar_text) )

      {

        // we have some text to display in the middle; see where we are.

        $show_text = ( $i >= $this->text_pos && $i < ( $this->text_pos + strlen($this->bar_text) ) );

        if ( $show_text )

        {

          $char = substr($this->bar_text, $i - $this->text_pos, 1);

          if ( strlen($char) < 1 )

            $char = ' ';

          else

            $hide = false;

        }

      }

      // determine color

      if ( $i > $bar_pos )

      {

        $hide ? $this->set_color_empty_hide() : $this->set_color_empty_show();

      }

      else

      {

        $hide ? $this->set_color_full_hide() : $this->set_color_full_show();

      }

      echo $char;

    }

    $this->set_color_reset();

    echo $this->bar_right;

  }

  #

  # PRIVATE METHODS

  #

  function set_color_full_hide()

  {

    if ( $this->color_state == self::COLOR_STATE_FULL_HIDE )

      return;

    $this->color_state = self::COLOR_STATE_FULL_HIDE;

    $fgcolor = 30 + $this->color_bar;

    $bgcolor = $fgcolor + 10;

    echo self::SHELL_ESCAPE . "[0;{$fgcolor};{$bgcolor};8m";

  }

  function set_color_full_show()

  {

    if ( $this->color_state == self::COLOR_STATE_FULL_SHOW )

      return;

    $this->color_state = self::COLOR_STATE_FULL_SHOW;

    $fgcolor = 30 + $this->color_text;

    $bgcolor = 40 + $this->color_bar;

    echo self::SHELL_ESCAPE . "[0;1;{$fgcolor};{$bgcolor}m";

  }

  function set_color_empty_hide()

  {

    if ( $this->color_state == self::COLOR_STATE_EMPTY_HIDE )

      return;

    $this->color_state = self::COLOR_STATE_EMPTY_HIDE;

    $fgcolor = 30 + $this->color_empty;

    $bgcolor = $fgcolor + 10;

    echo self::SHELL_ESCAPE . "[0;{$fgcolor};{$bgcolor};8m";

  }

  function set_color_empty_show()

  {

    if ( $this->color_state == self::COLOR_STATE_EMPTY_SHOW )

      return;

    $this->color_state = self::COLOR_STATE_EMPTY_SHOW;

    $fgcolor = 30 + $this->color_emptytext;

    $bgcolor = 40 + $this->color_empty;

    echo self::SHELL_ESCAPE . "[0;1;{$fgcolor};{$bgcolor}m";

  }

  function set_color_reset()

  {

    if ( $this->color_state == self::COLOR_STATE_RESET )

      return;

    $this->color_state = self::COLOR_STATE_RESET;

    echo self::SHELL_ESCAPE . "[0m";

  }

  /**

   * Converts a color name to an ASCII color code. Valid color names are black, red, green, yellow, blue, magenta, cyan, and white.

   * @param string Color name

   * @return int

   */

  private function color_to_code($color)

  {

    static $colors = array(

      'black' => 0,

      'red' => 1,

      'green' => 2,

      'yellow' => 3,

      'blue' => 4,

      'magenta' => 5,

      'cyan' => 6,

      'white' => 7

    );

    return ( isset($colors[$color]) ) ? $colors[$color] : $colors['white'];

  }

}