<?php
// $Id$

/**
 * @file
 * Google Chart API wrapper module.
 *
 * @see README.txt
 */


/**
 * Encodes the input to Google Chart notation
 * @param value The value to be encoded
 * @return the encoded data.
 */
function _googlechart_encode($value) {
  if ($value <= -1) {
    return '__';
  }
  else {
    $charTable = 
      'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-.';
    $secondChar = $value % 64;
    $firstChar = (int)(($value - $secondChar) / 64);
    return ($charTable[$firstChar] . $charTable[$secondChar]);
  }
}

/**
 * Checks whether the code supplied is a valid color code
 * @param color The code to be validated
 * @return true if the color code is valid, false if it's not
 */
function _googlechart_is_valid_color_code($color) {
  if (
      ctype_xdigit( (string)$color ) &&
      (strlen( (string)$color ) == 6 || strlen( (string)$color ) == 8)
     ) { // Valid color code.
    return true;
  }
  else {
    return false;
  }
}

/**
 * Checks if any shape markers are defined.
 * @param datasetIndex The dataset to be checked
 * @param valueIndex The data point to be checked
 * @param settings The settings array
 * @return the string to be appended to url (without the &chm= part)
 */
function _googlechart_shape_markers($datasetIndex, $valueIndex, $settings) {
  if (
      in_array($settings['shapemarker'][$datasetIndex][$valueIndex],
      array('a', 'c', 'd', 'o', 's', 'v', 'V', 'h', 'x'))
     ) {
    $url_chm .= $settings['shapemarker'][$datasetIndex][$valueIndex];
    if (_googlechart_is_valid_color_code
        ($settings['shapemarkercolor'][$datasetIndex][$valueIndex])
       ) {
      $url_chm .= ','. 
                  $settings['shapemarkercolor'][$datasetIndex][$valueIndex];
    }
    else { // If the color code is invalid, default it to black.
      $url_chm .= ',000000';
    }
    $url_chm .= ','. $datasetIndex .','. $valueIndex;
    if (ctype_digit
        ((string)$settings['shapemarkersize'][$datasetIndex][$valueIndex])
       ) {
      $url_chm .= ','.
                  $settings['shapemarkersize'][$datasetIndex][$valueIndex] .
                  '|';
    }
    else { // If the size is not a valid number, default it to 10.
      $url_chm .= ',10|';
    }
  }
  return $url_chm;
}

/**
 * The main function
 * @param data The array with the plot data. If you want to plot a single data
 *             set, you should put the data points as elements of the array. For
 *             multiple data sets, make each dataset a sub-array and put the
 *             points as the elements.
 * @param settings The array with settings. Each setting is made up of the key,
 *                 some settings also have parameters.
 * @see README.txt for details about both data (ch. 3b) and (especially)
 *                 settings (ch. 3c, ch. 5).
 * @return an error code, if failed, and the entire url pointing to the chart,
 * if succeeded.
 */
function googlechart_getchart($data, $settings) {
  // Define the error codes.
  define('ERROR_INVALID_DATASET', 0x10);
  define('ERROR_INVALID_DATASET_TYPE', 0x11);
  define('ERROR_INVALID_WIDTH', 0x12);
  define('ERROR_INVALID_HEIGHT', 0x13);
  define('ERROR_INVALID_TYPE', 0x14);
  define('ERROR_CHART_TOO_LARGE', 0x15);

  // Validate the datasets.
  $float = false;
  while ((list(, $val1) = each($data)) && ($float == false)) {
    if (is_array($val1)) { // Multiple data sets.
      while ((list(, $val2) = each($val1)) && ($float == false)) {
        if (!is_array($val2)) {
          if (is_numeric($val2)) {
            if (is_float($val2)) {
              $float = true;
            }
          }
          else { // $val2 is not numeric.
            return ERROR_INVALID_DATASET_TYPE;
          }
        }
        else { // $val2 is an array.
          return ERROR_INVALID_DATASET;
        }
      }
    }
    else { // Single data set.
      if (is_numeric($val1)) {
        if (is_float($val1)) {
          $float = true;
        }
      }
      else { // $val1 is not numeric.
        return ERROR_INVALID_DATASET_TYPE;
      }
    }
  }

  // Validate the settings.
  if ((!ctype_digit( (string) $settings['width'] )) ||
      ($settings['width'] < 1) ||
      ($settings['width'] > 1000)) { // Invalid width.
    return ERROR_INVALID_WIDTH;
  }
  if ((!ctype_digit( (string) $settings['height'] )) ||
      ($settings['height'] < 1) ||
      ($settings['height'] > 1000) ) { // Invalid height.
    return ERROR_INVALID_HEIGHT;
  }
  if (!in_array($settings['type'],
        array('lc', 'lxy', 'bhs', 'bvs', 'bhg', 'bvg', 'p', 'p3', 'v', 's'))
     ) { // Invalid chart type.
    return ERROR_INVALID_TYPE;
  }
  if (($settings['width'] * $settings['height']) >= 300000) {
    // The chart is too large.
    return ERROR_CHART_TOO_LARGE;
  }


  $url = 'http://chart.apis.google.com/chart?'.
         'chs='. $settings['width'] .'x'. $settings['height'] .
         '&amp;cht='. $settings['type'] .
         '&amp;chd=e:';

  if ($settings['type'] == 'lc') { // For a normal line chart,
    // quickly go through to find the maximum value to calculate the divider.
    $i = 0;
    foreach ($data as $val1) {
      if (is_array($val1)) {
        $maxVal[$i] = max($val1);
        ++$i;
      }
      else {
        $maxVal[0] = $val1;
      }
    }
    if ($float) {
      $divider = 4095 / (max($maxVal) * 10);
    }
    else {
      $divider = 4095 / max($maxVal);
    }
  }

  foreach ($data as $val1Index => $val1) {
    if (is_array($val1)) { // Multiple data sets.
      $single_data_set = false; ///< used when filling area under the graph
      if ($settings['type'] != 'lc') {
        // For any type other than lc, calculate the divider here.
        $divider = 4095 / max($val1);  
      }
      foreach ($val1 as $val2Index => $val2) { // No need to check if it's an 
        if ($float) {                          // array again.
          $url .= _googlechart_encode( (int)($val2 * 10 * $divider) );
        }
        else {
          $url .= _googlechart_encode( (int)($val2 * $divider) );
        }
        // Shape markers for that datapoint.
        $url_chm .= _googlechart_shape_markers(
                      $val1Index,
                      $val2Index,
                      $settings);
      }
      $url .= ',';
    }
    else { // Single data set.
      $single_data_set = true;
      $divider = 4095 / max($data);
      if ($float) {
        $url .= _googlechart_encode( (int)($val1 * 10 * $divider) );
      }
      else {
        $url .= _googlechart_encode( (int)($val1 * $divider) );
      }
      // Shape markers for that datapoint.
      $url_chm .= _googlechart_shape_markers(0, $val1Index, $settings);
    }
  }
  $markers_defined = false;
  if ($url_chm != '') {
    $url .= '&amp;chm='. rtrim($url_chm, '|');
    $markers_defined = true;
  }

  // Range markers.
  if ((is_array($settings['range']['direction'])) &&
      (is_array($settings['range']['start'])) &&
     (is_array($settings['range']['end']))) { // Only if all these settings are 
    $url_chm = '';                            // defined.
    foreach ($settings['range']['direction'] as $key => $dir) {
      switch ($dir) {
        case 'v': // Vertical marker.
          $url_chm_dir = 'R';
          break;
        case 'h': // Horizontal marker.
          $url_chm_dir = 'r';
          break;
      }
      if (_googlechart_is_valid_color_code($settings['range']['color'][$key])) {
        $url_chm_color = $settings['range']['color'][$key];
      }
      else { // If this is not a valid color, default it to light blue.
        $url_chm_color = 'eeeeff';
      }
      $url_chm .= $url_chm_dir .','.
                  $url_chm_color .',0,'.
                  $settings['range']['start'][$key] .','.
                  $settings['range']['end'][$key] .'|';
    }
    if ($url_chm != '') {
      if (!$markers_defined) {
        $url .= '&amp;chm=';
      }
      else {
        $url .= '|';
      }
      $url .= rtrim($url_chm, '|');
      $markers_defined = true;
    }
  }

  // Fill area.
  $url_chm = '';
  if ($single_data_set) { // For single data set, just fill the area under the
                          // graph.
    if (_googlechart_is_valid_color_code($settings['fill'])) {
      $url_chm = 'B,'. $settings['fill'] .',0,0,0|';
    }
  }
  else { // For multiple data sets, fill areas in between the lines.
    if (is_array($settings['fill'])) {
      foreach ($settings['fill'] as $top => $topVal) {
        foreach ($topVal as $bottom => $color) {
          if (_googlechart_is_valid_color_code($color)) {
            $url_chm .= 'b,'. $color .','. $top .','. $bottom .',0|';
          }
        }
      }
    }
  }
  if ($url_chm != '') {
    if (!$markers_defined) {
      $url .= '&amp;chm=';
    }
    else {
      $url .= '|';
    }
    $url .= rtrim($url_chm, '|');
    $markers_defined = true;
  }

  // Bar width / space between bars.
  if (isset($settings['barwidth'])) {
    $url .= '&amp;chbh='. $settings['barwidth'];
    if (isset($settings['barspace'])) {
      $url .= ','. $settings['barspace'];
    }
  }

  // Data set colors.
  if (isset($settings['datasetcolor'])) { // Are codes defined at all?
    if (is_array($settings['datasetcolor'])) { // Codes for several sets.
      $url .= '&amp;chco=';
      $i = 0;
      foreach ($settings['datasetcolor'] as $key => $color) {
        if (_googlechart_is_valid_color_code($color)) {
          if ($key != $i) {           // If a color declaration was omitted, a
            for (; $i < $key; ++$i) { // nice orange will be defaulted for each
              $url .= 'ff9900,';      // of the omitted sets.
            }
            $i = $key;
          }
          $url .= $color .','; // Append the current color
          ++$i;
        }
      }
    }
  }
  $url = rtrim($url, ',');

  // Data set line styles
  if (isset($settings['datasetstyle'])) {
    if (is_array($settings['datasetstyle'])) {
      $i = 0;
      foreach ($settings['datasetstyle'] as $key => $style) {
        if ($key != $i) { // If a declaration was omited, go for some defaults
          for (; $i < $key; ++$i) { // For each of the omitted sets
            $url_chls .= '1.5,1,0|';
          }
          $i = $key;
        }
        if (!isset($style['thick'])) {
          $url_chls .= '1.5';
        }
        else {
          $url_chls .= $style['thick'];
        }
        if (!isset($style['line'])) {
          $url_chls .= ',1';
        }
        else {
          $url_chls .= ','. $style['line'];
        }
        if (!isset($style['blank'])) {
          $url_chls .= ',0';
        }
        else {
          $url_chls .= ','. $style['blank'];
        }
        $url_chls .= '|';
        ++$i;
      }
      $url .= '&amp;chls='. rtrim($url_chls, '|');
    }
  }

  // Chart and background fill.
  $declared = false;
  for ($counter = 0; $counter <= 1; ++$counter) {
    switch ($counter) {
      case 0: // Background fill first,
        $bgOrCFull  = 'background';
        $bgOrCShort = 'bg';
        break;
      case 1: // and then chart fill.
        $bgOrCFull  = 'chart';
        $bgOrCShort = 'c';
        break;
    }
    $success = false; ///< stores whether at least one color was added
    if ($settings[$bgOrCFull .'filltype'] == 's') { // Solid fill
      if (_googlechart_is_valid_color_code(
            $settings[$bgOrCFull .'fillcolor'])) {
        $url_add .= 's,'. $settings[$bgOrCFull .'fillcolor'];
        $success = true;
      }
    }
    elseif ($settings[$bgOrCFull .'filltype'] == 'lg') {
      // Linear gradient fill
      $url_add = 'lg,';
      if ( (0 <= (int)$settings[$bgOrCFull .'fillangle']) &&
           ((int)$settings[$bgOrCFull .'fillangle'] <= 90)) {//Is angle 0 - 90?
        $url_add .= $settings[$bgOrCFull .'fillangle'];
        if (is_array($settings[$bgOrCFull .'fillcolor'])) { // Array of colors.
          $i = 0;
          foreach ($settings[$bgOrCFull .'fillcolor'] as $color) {
            if (_googlechart_is_valid_color_code($color)) {
              if ( (isset($settings[$bgOrCFull .'filloffset'][$i])) &&
                  (0 <= (float)$settings[$bgOrCFull .'filloffset'][$i]) &&
                  ((float)$settings[$bgOrCFull .'filloffset'][$i] <= 1)) {
                $url_add .= ','. $color .
                            ','. $settings[$bgOrCFull .'filloffset'][$i];
                $success = true; // A color was added.
              }
            }
            ++$i;
          }
        }
      }
    }
    elseif ($settings[$bgOrCFull .'filltype'] == 'ls') {
      // Linear stripes fill
      $url_add = 'ls,';
      if ( (0 <= (int)$settings[$bgOrCFull .'fillangle']) &&
           ((int)$settings[$bgOrCFull .'fillangle'] <= 90)) {//Is angle 0 - 90?
        $url_add .= $settings[$bgOrCFull .'fillangle'];
        if (is_array($settings[$bgOrCFull .'fillcolor'])) { // Array of colors
          $i = 0;
          foreach ($settings[$bgOrCFull .'fillcolor'] as $color) {
            if (_googlechart_is_valid_color_code($color)) {
              if ( (isset($settings[$bgOrCFull .'fillwidth'][$i])) &&
                  (0 <= (float)$settings[$bgOrCFull .'fillwidth'][$i]) &&
                  ((float)$settings[$bgOrCFull .'fillwidth'][$i] <= 1)) {
                $url_add .= ','. $color .','
                            . $settings[$bgOrCFull .'fillwidth'][$i];
                $success = true; // A color was added.
              }
            }
            ++$i;
          }
        }
      }
    }
    if ($success) { // If at least one color was added.
      if ($declared) {
        // If a previous (eg. background) definition was there, we can
        $url .= '|'. $bgOrCShort .','. $url_add;   // add it to the final url
      }
      else { // There was no declaration, so make one.
        $url .= '&amp;chf='. $bgOrCShort .','. $url_add;
        $declared = true;
      }
    }
  }

  // Labels
  // Chart title
  if (isset($settings['title'])) {
    $url .= '&amp;chtt='. preg_replace("/\\%0D\\%0A|\\%0A|\\%0D/", '|',
                                       urlencode($settings['title']));
    $colorDefined = false; ///< useful if only size is set
    if (_googlechart_is_valid_color_code($settings['titlecolor'])) {
      $colorDefined = true;
      $url .= '&amp;chts='. $settings['titlecolor'];
    }
    if (ctype_digit($settings['titlesize'])) {
      if ($colorDefined) {
        $url .= ','. $settings['titlesize'];
      }
      else {
        $url .= '&amp;chts=000000,'. $settings['titlesize'];
      }
    }
  }
  // Legend/pie chart labels
  if (is_array($settings['label'])) {
    $url .= '&amp;';
    if (($settings['type'] == 'p') || ($settings['type'] == 'p3')) { //Pie chart
      // Add a pie chart label declaration.
      $url .= 'chl=';
    }
    else { // Other chart type
      // Add a legend declaration.
      $url .= 'chdl=';
    }
    foreach ($settings['label'] as $key => $label) {
      $url .= $label;
      if (count($settings['label']) > ($key + 1)) {
        $url .= '|';
      }
    }
  }
  // Axis labels.
  if (is_array($settings['axis'])) {
    $url_chxt = '';
    $url_chxl = '';
    $url_chxp = '';
    $url_chxr = '';
    $url_chxs = '';
    $i = 0;
    foreach ($settings['axis'] as $axis => $values) {
      if ( ($axis == 'x') ||
           ($axis == 't') ||
           ($axis == 'y') ||
          ($axis == 'r') ) {
        if (is_array($values)) {
          foreach ($values as $key => $value) {
            $url_chxt .= $axis;
            $url_chxt .= ',';
            if (isset($value)) {
              $url_chxl .= $i .':|';
              if (is_array($value)) {
                $url_chxl .= implode('|', $value) .'|';
                if (isset($settings['axisposition'][$axis][$key])) {
                  $url_chxp .= $i .',';
                  if (is_array($settings['axisposition'][$axis][$key])) {
                    $url_chxp .=
                            implode(',', $settings['axisposition'][$axis][$key])
                            .'|';
                  }
                  else {
                    $url_chxp .= $settings['axisposition'][$axis][$key] .'|';
                  }
                }
              }
              else {
                $url_chxl .= $value .'|';
                if (isset($settings['axisposition'][$axis][$key])) {
                  $url_chxp .= $i .',';
                  $url_chxp .= $settings['axisposition'][$axis][$key] .'|';
                }
              }
              if ((isset($settings['axisrange'][$axis][$key]['start'])) &&
                  (isset($settings['axisrange'][$axis][$key]['end']))) {
                $url_chxr .= $i .','
                            . $settings['axisrange'][$axis][$key]['start'] .','
                            . $settings['axisrange'][$axis][$key]['end'] .'|';
              }
              $url_chxs_color = $settings['axiscolor'][$axis][$key];
              $url_chxs_size  = $settings['axissize'][$axis][$key];
              switch ($settings['axisalign'][$axis][$key]) {
                case 'l': // Left align
                  $url_chxs_align = '-1';
                  break;
                case 'c': // Centre align
                  $url_chxs_align = '0';
                  break;
                case 'r': // Right align
                  $url_chxs_align = '1';
                  break;
              }

              if (!isset($url_chxs_color)) { // If the color is not set,
                $url_chxs_color = '666666'; // default it to grey.
              }
              if (!isset($url_chxs_size)) { // If the size is not set,
                $url_chxs_size = '11.5';   // default it to 11.5.
              }
              $url_chxs_ = $i .','. $url_chxs_color .','. $url_chxs_size;
              if (!isset($url_chxs_align)) { // If the alignment is not present,
                $url_chxs_ .= '|';        // just omit the unneeded declaration.
              }
              else {
                $url_chxs_ .= ','. $url_chxs_align .'|';
              }
              if ($url_chxs_ != ($i .',666666,11.5|')) { //If it's not just all
                $url_chxs .= $url_chxs_;  // defaults then append it to the url.
              }
              ++$i;
            }
          }
        }
      }
    } // Check each declaration, and append it to the url if not empty.
    if ($url_chxt != '') {
      $url .= '&amp;chxt='. rtrim($url_chxt, ',');
    }
    if ($url_chxl != '') {
      $url .= '&amp;chxl='. rtrim($url_chxl, '|');
    }
    if ($url_chxp != '') {
      $url .= '&amp;chxp='. rtrim($url_chxp, '|');
    }
    if ($url_chxr != '') {
      $url .= '&amp;chxr='. rtrim($url_chxr, '|');
    }
    if ($url_chxs != '') {
      $url .= '&amp;chxs='. rtrim($url_chxs, '|');
    }
  }

  // Grid lines.
  if (is_array($settings['grid'])) {
    if (isset($settings['grid']['xstep'])) {
      $url .= '&amp;chg='. $settings['grid']['xstep'];
    }
    else { // If xstep is not defined, make every 1st level label of x axis
      if (isset($settings['axis']['x'][0])) { // where the gridlines appear.
        $count = count($settings['axis']['x'][0]) - 1;
        if ($count == 0) { // If there is only one label on x axis
          $count = 10000; // make 100/count very small so it is rounded up to 0.
        }  
        $url .= '&amp;chg='. number_format(100 / $count, 1, '.', '');
      }
      else { // If that also fails, make no x-axis gridlines whatsoever
        $url .= '&amp;chg=100';
      }
    }
    if (isset($settings['grid']['ystep'])) {
      $url .= ','. $settings['grid']['ystep'];
    }
    else { // If ystep is not defined, make every 1st level label of y axis 
      if (isset($settings['axis']['y'][0])) { // where the gridlines appear.
        $count = count($settings['axis']['y'][0]) - 1;
        if ($count == 0) { // If there is only one label on y axis,
          $count = 10000; // make 100/count very small so it is rounded up to 0.
        }
        $url .= ','. number_format(100 / $count, 1, '.', '');
      }
      else { // If that also fails, make no y-axis gridlines whatsoever
        $url .= ',100';
      }
    }
    $grid_defined = true;
  }
  // Grid line styles
  if (is_array($settings['gridstyle'])) {
    if ($grid_defined) { // Don't bother if there are no grids defined
      if ( (isset($settings['gridstyle']['line'])) &&  // Only add if all of the
           (isset($settings['gridstyle']['blank'])) ) { // settings are present.
        $url .= ','. $settings['gridstyle']['line'] .
                ','. $settings['gridstyle']['blank'];
      }
    }
  }

  // Return the whole resultant url.
  return $url;
}