<?php
/*=====================================================================*\
|| ###################################################################
|| # ViewSVN [#]version[#]
|| # Copyright ©2002-[#]year[#] Blue Static
|| #
|| # This program is free software; you can redistribute it and/or modify
|| # it under the terms of the GNU General Public License as published by
|| # the Free Software Foundation; version [#]gpl[#] of the License.
|| #
|| # This program is distributed in the hope that it will be useful, but
|| # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|| # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|| # more details.
|| #
|| # You should have received a copy of the GNU General Public License along
|| # with this program; if not, write to the Free Software Foundation, Inc.,
|| # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
|| ###################################################################
\*=====================================================================*/

/**
* Diff
*
* This class parses a diff file from a unified diff file and turns it
* into a HTML-prettied output
*
* @author		Blue Static
* @copyright	Copyright (c)2002 - [#]year[#], Blue Static
* @version		$Revision$
* @package		ViewSVN
*
*/
class Diff 
{
	/**
	* Raw unified diff text
	* @var string
	*/
	private $raw;
	
	/**
	* The current index (file)
	* @var string
	*/
	private $index;
	
	// ###################################################################
	/**
	* Constructor
	*
	* @param	string	Raw unified diff output
	*/
	public function __construct($raw)
	{
		$this->raw = $raw;
	}
	
	// ###################################################################
	/**
	* This function initiates the parsing process and returns the output
	* in hunks, line-by-line
	*
	* @return	array	Array of outputted hunked information
	*/
	public function fetch()
	{
		global $viewsvn;
		
		$chunk = 0;
		$indexcounter = null;
		$curprop = '';
		
		$delstack = array();
		
		foreach ($this->raw AS $line)
		{
			if (preg_match('#^@@ \-([0-9]*),([0-9]*) \+([0-9]*),([0-9]*) @@$#', $line, $bits))
			{
				$property = false;
				$delstack = array();
				$this->diff["$index"][ ++$chunk ]['hunk'] = array('old' => array('line' => $bits[1], 'count' => $bits[2]), 'new' => array('line' => $bits[3], 'count' => $bits[4]));
				$lines['old'] = $this->diff["$index"]["$chunk"]['hunk']['old']['line'] - 1;
				$lines['new'] = $this->diff["$index"]["$chunk"]['hunk']['new']['line'] - 1;
				continue;
			}
			else if (preg_match('#^Property changes on: (.*?)$#', $line, $bits))
			{
				$property = true;
				$index = $bits[1];
				$this->diff["$index"]['props'] = array();
				continue;
			}
			
			if ($indexcounter <= 3 AND $indexcounter !== null)
			{
				$indexcounter++;
				continue;
			}
			else if ($indexcounter == 3)
			{
				$indexcounter = null;
				continue;
			}
			
			if (preg_match('#^([\+\- ])(.*)#', $line, $matches) AND !$property)
			{
				$act = $matches[1];
				$content = $matches[2];
				
				if ($act == ' ')
				{
					$this->diff["$index"]["$chunk"][] = array(
						'line'		=> $content,
						'act'		=> '',
						'oldlineno'	=> ++$lines['old'],
						'newlineno'	=> ++$lines['new']
					);
					
					$delstack = array();
				}
				else if ($act == '+')
				{		
					// potential line delta
					if (sizeof($delstack) > 0)
					{
						$lastline = array_shift($delstack);
						
						if ($delta = @$this->_fetchDiffExtent($lastline['line'], $content))
						{
							if (strlen($lastline['line']) > ($delta['start'] - $delta['end']))
							{
								$end = strlen($lastline['line']) + $delta['end'];
								BSRegister::Debug("RM delta- = " . $end);
								$change = '{@-' . '-}' . substr($lastline['line'], $delta['start'], $end - $delta['start']) . '{/@-' . '-}';
								$this->diff["$index"]["$chunk"]["$lastline[INDEX]"]['line'] = substr($lastline['line'], 0, $delta['start']) . $change . substr($lastline['line'], $end);
							}
							
							if (strlen($content) > $delta['start'] - $delta['end'])
							{
								$end = strlen($content) + $delta['end'];
								BSRegister::Debug("MK delta+ = " . $end);
								$change = '{@+' . '+}' . substr($content, $delta['start'], $end - $delta['start']) . '{/@+' . '+}';
								$content = substr($content, 0, $delta['start']) . $change . substr($content, $end);
							}
						}
					}
					
					$this->diff["$index"]["$chunk"][] = array(
						'line'		=> $content,
						'act'		=> '+',
						'oldlineno'	=> '',
						'newlineno'	=> ++$lines['new']
					);
				}
				else if ($act == '-')
				{
					$this->diff["$index"]["$chunk"][] = $thearray = array(
						'line'		=> $content,
						'act'		=> '-',
						'oldlineno'	=> ++$lines['old'],
						'newlineno'	=> ''
					);
					
					$key = sizeof($this->diff["$index"]["$chunk"]) - 2;
					$thearray['INDEX'] = $key;
					
					array_push($delstack, $thearray);
				}
			}
			// whitespace lines
			else
			{
				if (preg_match('#^Index: (.*?)$#', $line, $matches))
				{
					$index = $matches[1];
					$indexcounter = 1;
					$chunk = 0;
					continue;
				}
				
				if ($property)
				{
					if (preg_match('#^__*_$#', trim($line)))
					{
						BSRegister::Debug("skipping: $line");
						continue;
					}
					
					if (preg_match('#Name: (.*?)$#', $line, $matches))
					{
						$curprop = $matches[1];
						BSRegister::Debug("prop: $curprop");
						continue;
					}
					else
					{
						if (preg_match('#^\s+?\+(.*)#', $line, $matches))
						{
							$mode = 'add';
							$this->diff["$index"]['props']["$curprop"]['add'] .= $matches[1];
						}
						else if (preg_match('#^\s+?\-(.*)#', $line, $matches))
						{
							$mode = 'del';
							$this->diff["$index"]['props']["$curprop"]['del'] .= $matches[1];
						}
						else if (!preg_match('#^\s+[\+\- ](.*)#', $line) AND trim($line) != '')
						{
							$this->diff["$index"]['props']["$curprop"]["$mode"] .= "\n" . $line;
						}
						continue;
					}
				}
				
				$this->diff["$index"]["$chunk"][] = array(
					'line'		=> '',
					'act'		=> '',
					'oldlineno'	=> ++$lines['old'],
					'newlineno'	=> ++$lines['new']
				);
				
				$delstack = array();
			}
		}
		
		return $this->diff;
	}
	
	// ###################################################################
	/**
	* Returns the amount of change that occured between two lines
	*
	* @param	string	Old line
	* @param	string	New line
	*
	* @return	array	Difference of positions
	*/
	private function _fetchDiffExtent($old, $new)
	{
		global $viewsvn;
		
		$start = 0;
		$min = min(strlen($old), strlen($new));
		
		BSRegister::Debug("min1 = $min");
		
		while ($start < $min AND $old["$start"] == $new["$start"])
		{
			$start++;
		}
		
		$end = -1;
		$min = $min - $start;
		
		BSRegister::Debug("min2 = $min");
		
		BSRegister::Debug("checking: " . $old[ strlen($old) + $end ] . ' ==  ' . $new[ strlen($new) + $end ]);
		
		while (-$end <= $min AND $old[ strlen($old) + $end ] == $new[ strlen($new) + $end ])
		{
			$end--;
		}
		
		return array('start' => $start, 'end' => $end + 1);
	}
}

/*=====================================================================*\
|| ###################################################################
|| # $HeadURL$
|| # $Id$
|| ###################################################################
\*=====================================================================*/
?>