<?php

	class qa_event_logger {
		
		function init_queries($tableslc)
		{
			if (qa_opt('event_logger_to_database')) {
				$tablename=qa_db_add_table_prefix('eventlog');
				
				if (!in_array($tablename, $tableslc)) {
					require_once QA_INCLUDE_DIR.'king-app/users.php';
					require_once QA_INCLUDE_DIR.'king-db/maxima.php';

					return 'CREATE TABLE ^eventlog ('.
						'datetime DATETIME NOT NULL,'.
						'ipaddress VARCHAR (15) CHARACTER SET ascii,'.
						'userid '.qa_get_mysql_user_column_type().','.
						'handle VARCHAR('.QA_DB_MAX_HANDLE_LENGTH.'),'.
						'cookieid BIGINT UNSIGNED,'.
						'event VARCHAR (20) CHARACTER SET ascii NOT NULL,'.
						'params VARCHAR (800) NOT NULL,'.
						'KEY datetime (datetime),'.
						'KEY ipaddress (ipaddress),'.
						'KEY userid (userid),'.
						'KEY event (event)'.
					') ENGINE=MyISAM DEFAULT CHARSET=utf8';
				}
			}
		}

		
		function admin_form(&$qa_content)
		{

		//	Process form input

			$saved=false;
			
			if (qa_clicked('event_logger_save_button')) {
				qa_opt('event_logger_to_database', (int)qa_post_text('event_logger_to_database_field'));
				qa_opt('event_logger_to_files', qa_post_text('event_logger_to_files_field'));
				qa_opt('event_logger_directory', qa_post_text('event_logger_directory_field'));
				qa_opt('event_logger_hide_header', !qa_post_text('event_logger_hide_header_field'));

				$saved=true;
			}
		
		//	Check the validity of the currently entered directory (if any)
		
			$directory=qa_opt('event_logger_directory');
			
			$note=null;
			$error=null;
			
			if (!strlen($directory))
				$note='Please specify a directory that is writable by the web server.';
			elseif (!file_exists($directory))
				$error='This directory cannot be found. Please enter the full path.';
			elseif (!is_dir($directory))
				$error='This is a file. Please enter the full path of a directory.';
			elseif (!is_writable($directory))
				$error='This directory is not writable by the web server. Please choose a different directory, use chown/chmod to change permissions, or contact your web hosting company for assistance.';
				
		//	Create the form for display

			qa_set_display_rules($qa_content, array(
				'event_logger_directory_display' => 'event_logger_to_files_field',
				'event_logger_hide_header_display' => 'event_logger_to_files_field',
			));
			
			return array(
				'ok' => ($saved && !isset($error)) ? 'Event log settings saved' : null,
				
				'fields' => array(
					array(
						'label' => 'Log events to <code>'.QA_MYSQL_TABLE_PREFIX.'eventlog</code> database table',
						'tags' => 'name="event_logger_to_database_field"',
						'value' => qa_opt('event_logger_to_database'),
						'type' => 'checkbox',
					),

					array(
						'label' => 'Log events to daily log files',
						'tags' => 'name="event_logger_to_files_field" id="event_logger_to_files_field"',
						'value' => qa_opt('event_logger_to_files'),
						'type' => 'checkbox',
					),
					
					array(
						'id' => 'event_logger_directory_display',
						'label' => 'Directory for log files - enter full path:',
						'value' => qa_html($directory),
						'tags' => 'name="event_logger_directory_field"',
						'note' => $note,
						'error' => qa_html($error),
					),
					
					array(
						'id' => 'event_logger_hide_header_display',
						'label' => 'Include header lines at top of each log file',
						'type' => 'checkbox',
						'tags' => 'name="event_logger_hide_header_field"',
						'value' => !qa_opt('event_logger_hide_header'),
					),
				),
				
				'buttons' => array(
					array(
						'label' => 'Save Changes',
						'tags' => 'name="event_logger_save_button"',
					),
				),
			);
		}

		
		function value_to_text($value)
		{
			if (is_array($value)) {
				$text='array('.count($value).')';
			} elseif (strlen((string)$value)>40) {
				$text=substr($value, 0, 38).'...';
			} else {
				$text=$value;
			}
				
			return strtr((string)$text, "\t\n\r", '   ');
		}
	
	
		function process_event($event, $userid, $handle, $cookieid, $params)
		{
			if (qa_opt('event_logger_to_database')) {
				$paramstring='';
				
				foreach ($params as $key => $value)
					$paramstring.=(strlen($paramstring) ? "\t" : '').$key.'='.$this->value_to_text($value);
				
				qa_db_query_sub(
					'INSERT INTO ^eventlog (datetime, ipaddress, userid, handle, cookieid, event, params) '.
					'VALUES (NOW(), $, $, $, #, $, $)',
					qa_remote_ip_address(), $userid, $handle, $cookieid, $event, $paramstring
				);			
			}
			
			if (qa_opt('event_logger_to_files')) {

			//	Substitute some placeholders if certain information is missing
				
				if (!strlen($userid))
					$userid='no_userid';
				
				if (!strlen($handle))
					$handle='no_handle';
				
				if (!strlen($cookieid))
					$cookieid='no_cookieid';
					
				$ip=qa_remote_ip_address();
				if (!strlen($ip))
					$ip='no_ipaddress';
					
			//	Build the log file line to be written
				
				$fixedfields=array(
					'Date' => date('Y\-m\-d'),
					'Time' => date('H\:i\:s'),
					'IPaddress' => $ip,
					'UserID' => $userid,
					'Username' => $handle,
					'CookieID' => $cookieid,
					'Event' => $event,
				);
				
				$fields=$fixedfields;
				
				foreach ($params as $key => $value)
					$fields['param_'.$key]=$key.'='.$this->value_to_text($value);
				
				$string=implode("\t", $fields);
			
			//	Build the full path and file name
			
				$directory=qa_opt('event_logger_directory');
			
				if (substr($directory, -1)!='/')
					$directory.='/';
					
				$filename=$directory.'q2a-log-'.date('Y\-m\-d').'.txt';
				
			//	Open, lock, write, unlock, close (to prevent interference between multiple writes)
				
				$exists=file_exists($filename);

				$file=@fopen($filename, 'a');
				
				if (is_resource($file)) {
					if (flock($file, LOCK_EX)) {
						if ( (!$exists) && (filesize($filename)===0) && !qa_opt('event_logger_hide_header') )
							$string="Question2Answer ".QA_VERSION." log file generated by Event Logger plugin.\n".
								"This file is formatted as tab-delimited text with UTF-8 encoding.\n\n".
								implode("\t", array_keys($fixedfields))."\textras...\n\n".$string;
						
						fwrite($file, $string."\n");
						flock($file, LOCK_UN);
					}

					fclose($file);
				}
			}
		}
	
	}
	

/*
	Omit PHP closing tag to help avoid accidental output
*/