<?php if(!defined('IN_GS')){ die('you cannot load this page directly.'); }
     
     /*
      * Logging Class for GetSimple
      * 
      * Writes log records to log files in data/other/logs
      * Deletes Log Files
      * No methods for reading log files ATM
      *
      * @author Shawn Alverson
      *
      * @requires basic.php
      *
      * @uses SimpleXMLExtended
      * @uses XMLSave
      * @uses addCData
      * @uses GSDATAOTHERPATH
      *
      * @param string $filename - filename.log
      * @param bool $logdefaults=true - logs default info, see defaults()
      *
      * example
      * $class= new GS_Logging_Class('logfilename.log'); // new log record for logfile (filename)
      * $class->add('field','value'); // add record entries to log record
      * $class->save(); // write log record to file
      * $class->clear(); // removes log file
      */
      
     class GS_Logging_Class {
     
             private $_xml;
             private $_xmlfile;
             private $_entry;
       
             function __construct($filename,$logdefaults=true) {
                     // check filename, must be .log
                     
                     if($this->validFilename($filename)){
                         $this->_xmlfile = GSDATAOTHERPATH.'logs/'.$filename;
                         if ( ! file_exists($this->_xmlfile) )  { 
                                 $this->_xml = new SimpleXMLExtended('<channel></channel>');
                         } else {
                                 $xmldata = file_get_contents($this->_xmlfile);
                                 $this->_xml = new SimpleXMLExtended($xmldata);
                         }    
                         
                         // create entry and add date
                         $thislog = $this->_xml->addChild('entry');
                         $thislog->addChild('date', date('r'));                
                         $this->_entry = $thislog;
                         
                         if($logdefaults==true) $this->defaults();  
                     }
                     else return false;
             }
     
              /* 
              * Checks valid filenames
              * Filename must have extension .log and not have path info
              *
              * @thows Exception
              * @returns bool success
              * 
              */   
             private static function validFilename($filename){
                     $pathinfo=pathinfo($filename);
                     if(!isset($pathinfo['extension']) || strtolower($pathinfo['extension']) != 'log' || $pathinfo['dirname']!='.'){
                       throw new Exception("Filename is not valid in GS_Logging_Class");                 
                     }  else {
                       return true;
                     }
             }
             
             /* 
              * Add default fields to log
              * Adds Username(If logged in),IP Address
              * 
              */   
             private function defaults(){
                     GLOBAL $USR;
                     
                     if(isset($USR)){
                       $cdata = $this->_entry->addChild('Username');
                       $cdata->addCData(htmlentities($USR, ENT_QUOTES));
                     }
                     
                     $cdata = $this->_entry->addChild('IP_Address');
                     $ip = getenv("REMOTE_ADDR"); 
                     $cdata->addCData(htmlentities($ip, ENT_QUOTES));  
             }
     
             /* 
              * Save Log Record
              * Writes file
              * 
              * @return success
              */    
             public function save(){
                     return XMLsave($this->_xml, $this->_xmlfile);
             }
     
             /* 
              * Clear Log File
              * Deletes Log File
              * 
              * @return success
              */    
             public function clear(){
                     if (is_file($this->_xmlfile)) {
                             $res = unlink($this->_xmlfile);
                             exec_action('logfile_delete');
                             return $res;
                     }
             }
             
             /* 
              * Add Log Record Field
              * 
              * @param string $field
              * @param string $value
              *
              * @return success
              */    
             public function add($field,$value){
                     if(isset($field) && isset($value) && isset($this->_entry)){
                           $cdata = $this->_entry->addChild(htmlentities($field, ENT_QUOTES));
                           $cdata->addCData(htmlentities($value, ENT_QUOTES));
                     }  
             }
       
     } // end of class                   
     
     ?>