<?php
// $Id$

/**
 * @mainpage Google Chart API Wrapper
 * Easy to use chart-generating routines.
 *
 * 
 * 
 * 
 **SIMPLE HOWTO:
 * The one and only function noticeable to the user
 * is googlechart_get_graph($data,$settings,$datasettings).
 * Let's look through it parameters:
 * 
 * 
 * $data - it's an array where all presented data is specified.
 * In chart you can show multiple datasets at once. In this case
 * you need to pass $data as a array of arrays of value (i.e. 2d array)
 * For example.
 *  $data=array(array(1,2,3,4,5),array(1,4,9,25,36),array(0,1,2,3,4);
 *  Each value must be a positive integer in range between 0-1000.
 *  If you want to ommit a value (putting blank space in the chart),
 *  place -1 instead.
 * 
 * 
 * $settings - where all global settings are, i.e. not specific
 * to a certain dataset. $settings is an associative array. It's
 * structure goes this way:
 *  'type' => (string) it's the type of the chart
 *  Allowed values: line, linexy, pie, pie3d, bar_hs (horizontal stacked),
 *  bar_vs (vertical), bar_hg (grouped), bar_vg, venn, scatter
 *  
 *  'width' => (integer) width of the chart
 *  
 *  'height' => (integer) height of the chart
 * 
 *  'title' => (string) title, placed on the top. Multiple lines are
 *  allowed.
 * 
 *  'color' => (array) all global colors are placed here. You can
 *  specify color by standard Web notation RRGGBB or by RRGGBBAA (AA means
 *  alpha channel - needed for transparency). 'color' is also
 *  an associative array:
 *    'title' => (string) color of the title
 *    'bgcolor' => (string) background color of the whole chart, goes beneath
 *    chbhcolor.
 *    'chbgcolor' => (string) background color of the graph part of the chart.
 *  
 *  'axis' => (array) another array, this time it contains various options
 *  regarding axes:
 *    'type' => (string) positioning of an axis.
 *    Allowed values: 'y' (left), 'x' (bottom), 't' (top), 'r' (right)
 *    'style' => (array) axis font settings:
 *        'color' => (string) text color
 *        'fontize' => (integer) font size, in pixels
 *        'alignment' => (string) alignment of text
 *        Allowed values: center, left, right
 *
 *  
 * $datasettings => (array) (optional) other settings particular
 * to one of the datasets. Elements of an array should be in the same
 * order as in $data parameter.
 *   'color' => (string) dataset color (as it's drew on the chart)
 *   'legend' => (string) name of the dataset. It will be displayed in
 *   the legend box.
 *   'linestyle' => (array) array of three integers:
 *     0 => thickness of the line (in pixels)
 *     1 => length of line segment
 *     2 => length of blank segment
 * 
 */


/*
 * Internal function. Encodes data set into a
 * simple encoding (referring to Google Chart API).
 */
function _googlechart_encode_simple($data)
{
	$decriptor='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
	$ret='';
	foreach($data as $key)
	{
    $ret .= $decriptor[$key];
	}
  return $ret;
}


/*
 * Internal function. Encodes data set into a
 * text encoding (referring to Google Chart API).
 */
function _googlechart_encode_text($data)
{
  $ret='';
  $prefix='';
  foreach($data as $key)
  {
  	$ret.=$prefix . (($key-($key%10))/10) .'.'. ($key%10);
  	$prefix=',';
  }
  return $ret;
}

/*
 * Internal function. Encodes data set into a
 * extended encoding (referring to Google Chart API).
 */
function _googlechart_encode_extended($data)
{
  $decriptor='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._,';
	$ret='';
  foreach($data as $key)
  {
    $rest=$key%64;
    $first=($key-$rest)/64;
    $ret.=$decriptor[$first] . $decriptor[$rest];
  }
  return $ret;
}


/*
 * Main Google Chart API Wrapper function. It produces an url
 * to Google Chart image based on $data parameter, using
 * presentation specified in $settings. If provided,
 * additional formatting can be applied by $datasettings.
 * 
 * For more information refer to Google Chart API Wrapper Documentation.
 * @param $data
 *        One dimensional array of values when one set of data is given
 *        or two dimensional when multiple sets of data are given
 * @param $settings
 *        Array of global chart presentation options, like size of the
 *        image, main title etc.
 * @param $datasettings
 *        Array of additional formatting settings, specific to each set
 *        of data provided in $data parameter.
 */
function googlechart_get_graph($data, $settings, $datasettings=array())
{

	$request=array(
  'chd' => '',
	
  'chxt' => array(),
  'chxl' => array(),
  'chxp' => array(),
  'chxr' => array(),
  'chxs' => array(),
	
  'chco' => array(),
  'chdl' => array(),
	'chls' => array(),
	);
	
	$request_on=array();
  
	// Default settings
	if(!array_key_exists('type',$settings)) $settings['type']='pie3d';
  if(!array_key_exists('width',$settings)) $settings['width']=200;
	if(!array_key_exists('height',$settings)) $settings['height']=100;
	
	/// CHART TYPE
//	 *  'type' => (string) it's the type of the chart
// *  Allowed values: line, linexy, pie, pie3d, bar_hs (horizontal stacked),
// *  bar_vs (vertical), bar_hg (grouped), bar_vg, venn, scatter
 
	$decriptor=array(
	  'pie3d' => 'p3','pie' => 'p',
	  'linexy' => 'lxy', 'line'=>'lc',
	  'bar_hs' => 'bhs', 'bar_vs' => 'bvs', 'bar_hg' => 'bhg','bar_vg' => 'bvg',
	  'venn' => 'v',
	  'scatter' => 's'
	  ); //So-called translation array.
	if(!isset($decriptor[$settings['type']]))
    error_log("Incorrect Google Graph type.");
	else
    $request['cht']=$decriptor[$settings['type']];
	
	//CHART SIZE
	if(!is_int($settings['width']) || !is_int($settings['height']))
    error_log('Incorrect Google Graph size.');
  
  $request['chs']= $settings['width'] .'x'. $settings['height'];
  
  //CHART DATA
  reset($data);
  if(!is_array(current($data))) $data=array($data);
  $prefix='t:';
  foreach($data as $dataset)
  {
    $request['chd'].=$prefix._googlechart_encode_text($dataset);
    $prefix='|';
  }
  
  //CHART TITLE (& FONTSIZE & COLRO)
  if(array_key_exists('title',$settings))
  {
  	$title=$settings['title'];
  	$title=str_replace(' ','+',$title);
  	$title=str_replace('\n','|',$title);
    $request['chtt']=$title;
  }
  
  //CHART AXES
  $request['chxt']=array();
  $request['chxl']=array();
  $request['chxp']=array();
  $request['chxr']=array();
  $request['chxs']=array();
  if(array_key_exists('axis',$settings))
  {
  	$i=0;
  	foreach($settings['axis'] as $axis)
  	{
  		$request['chxt'][]=$axis['type'];
  		if(array_key_exists('value',$axis))
  		  $request['chxl'][]=$i .':|'. implode('|',$axis['value']);
      if(array_key_exists('position',$axis))
        $request['chxp'][]=$i .','. implode(',',$axis['position']);
      if(array_key_exists('range',$axis))
        $request['chxr'][]=$i .','. $axis['range'][0] .','. $axis['range'][1];
        
      if(array_key_exists('style',$axis))
      {
      	$tmp=$i .','. $axis['style']['color'];
      	if(array_key_exists('fontsize',$axis['style']))
      	{
          $tmp.=','. $axis['style']['fontsize'];
          if(array_key_exists('alignment',$axis['style']))
          {
          	switch($axis['style']['alignment'])
          	{
          		case 'center': $tmp.= ',0'; break;
          		case 'left': $tmp.= ',-1'; break;
          		case 'right': $tmp.= ',1'; break;
          	}
          }
        }
          
      	
        $request['chxs'][]=$tmp;
      }
        
  		++$i;
  	}
    $request['chxt']=implode(",",$request['chxt']);
    $request['chxl']=implode("|",$request['chxl']);
    $request['chxp']=implode('|',$request['chxp']);
    $request['chxr']=implode("|",$request['chxr']);
    $request['chxs']=implode("|",$request['chxs']);
  	
  }
    
  ////DATASETTINGS
  if(count($datasettings)>0)
  {
   	foreach($data as $key=>$dataset)
  	{
  		if(array_key_exists($key,$datasettings))
  		$datasett=$datasettings[$key];
  		else $datasett=array();
  //COLOR
  		if(array_key_exists('color',$datasett))
  		{
  			$request['chco'][]=$datasett['color'];
  			$request_on['chco']=1;
  		}
  		else $request['chco'][]='000000';
  //LEGEND
  		if(array_key_exists('legend',$datasett))
  		{
  			$request['chdl'][]=$datasett['legend'];
  			$request_on['chdl']=1;
  		}
  		else $request['chdl'][]='';
  //LINE STYLE
      if(array_key_exists('style',$datasett))
      { 
        if(count($datasett['style'])==3) 
          $request['chls'][]=$datasett['style'][0] .','.$datasett['style'][1] .','.$datasett['style'][2];
          $request_on['chls']=1;
      } else
        $request['chls'][]='2,2,0';
          
  	}
  	
  	if(array_key_exists('chco',$request_on))
      $request['chco']=implode(",",$request['chco']);
    else 
      $request['chco']='';
      
    if(array_key_exists('chdl',$request_on))
      $request['chdl']=implode("|",$request['chdl']);
    else
      $request['chdl']='';
      
      
    if($settings['type']=='pie3d' || $settings['type']=='pie')
    {
      $request['chl']=$request['chdl'];
      unset($request['chdl']);
    }
    
    if(array_key_exists('chls',$request_on))
      $request['chls']=implode("|",$request['chls']);
    else
      $request['chls']='';
    
    
  }

  
  //FINAL STUFF
   
  $request_string='http://chart.apis.google.com/chart?'; //Resulting request url
  $prefix='';
  foreach($request as $key=>$value)
  {
  	if($value=='') continue;
  	if(is_array($value)) continue;
  	$request_string.=$prefix.$key.'='.$value;
  	$prefix='&';
  }
  return $request_string;
}

/*
$set=array(
'type'=>'line',
'width'=> 300,
'height'=>200,
'title' => 'My little chart\nSo much to do!',
'color' => array(
    'title' => 'FF0000'
    ),
    
'axis' => array(
    array(
    'type' => 'y',
    'style'=>array('color'=>'FF0000'),
    'value'=>array('Pon','Wt','Sr'),
    'position'=>array(0,10,100)
    
    ),
        array(
    'type' => 'y',
        'style'=>array('color'=>'000000','fontsize'=>'22','alignment'=>'center'),
    'value'=>array('Pon','Wt','Sr'),
    'position'=>array(0,20,100)
    
    )
    ),
);
$dat[0][]=1;
$dat[0][]=20;
$dat[0][]=50;
$dat[0][]=53;
$dat[0][]=56;
$dat[0][]=60;
$dat[0][]=610;

$dat[1][]=900;
$dat[1][]=800;
$dat[1][]=750;
$dat[1][]=725;
$dat[1][]=713;
$dat[1][]=707;
$dat[1][]=704;


$ds=array(
array('legend'=> 'Dataset1'),
array('legend'=> 'Dataset2', 'color' => '0000FF','style' => array(2,2,2))
);
*/