<?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 array
	*/
	private $raw;
	
	/**
	* The current index (file)
	* @var string
	*/
	private $index;
	
	/**
	* The array index of where capturing of diff data starts
	* @var integer
	*/
	private $captureStart = 0;
	
	/**
	* Current hunk that is being processed
	* @var integer
	*/
	private $hunkId = 0;
	
	/**
	* The lines on which hunks start
	* @var array
	*/
	private $hunkLines = array('old' => array('line' => 0, 'count' => 0), 'new' => array('line' => 0, 'count' => 0));
	
	/**
	* The parsed diff output
	* @var array
	*/
	private $diff = array();
	
	// ###################################################################
	/**
	* 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()
	{
		$this->diff = array();
		
		for ($i = 0; $i < sizeof($this->raw); $i++)
		{
			$line = $this->raw[$i];
			
			if (preg_match('/^Index: (.*)/', $line, $index))
			{
				$this->_processFile(array_slice($this->raw, $this->captureStart, $i - $this->captureStart));
				$this->captureStart = $i;
				$this->index = $index[1];
			}
			else if (preg_match('/Property changes on: (.*)/', $line, $index))
			{
				$this->index = $index[1];
				$this->_processProperties(array_slice($this->raw, 2));
			}
		}
		$this->_processFile(array_slice($this->raw, $this->captureStart));
		
		return $this->diff;
	}
	
	// ###################################################################
	/**
	* Processes a file part of a diff
	*
	* @param	array	An array of lines that make up a file chunk
	*/
	private function _processFile($lines)
	{
		preg_match_all('/[\-\+]{3}\s+(.*)\s+\(revision ([0-9]*)\)/', $lines[2] . "\n" . $lines[3], $revs);
		$this->diff[$this->index]['revision']['low'] = $revs[2][0];
		$this->diff[$this->index]['revision']['high'] = $revs[2][1];
		
		$this->hunkId = 0;
		
		$captureStart = 4;
		
		for ($i = 4; $i < sizeof($lines); $i++)
		{
			$line = $lines[$i];
			
			if (preg_match('/^@@ \-([0-9]*),([0-9]*) \+([0-9]*),([0-9]*) @@/', $line, $hunkHead))
			{
				$this->hunkLines = array('old' => array('line' => $hunkHead[1], 'count' => $hunkHead[2]), 'new' => array('line' => $hunkHead[3], 'count' => $hunkHead[4]));
				$this->_processHunk(array_slice($lines, $captureStart, $i - $captureStart));
				$captureStart = $i;
				$this->hunkId++;
			}
			else if (preg_match('#^__*_$#', $line))
			{
				$this->_processHunk(array_slice($lines, $captureStart, $i - $captureStart));
				$this->_processProperties(array_slice($lines, $i));
				return;
			}
		}
		$this->_processHunk(array_slice($lines, $captureStart));
	}
	
	// ###################################################################
	/**
	* This processes an individual hunk of a file
	*
	* @param	array	Array of lines
	*/
	private function _processHunk($lines)
	{
		$delstack = array();
		for ($i = 1; $i < sizeof($lines); $i++)
		{
			$line = $lines[$i];
			
			if (preg_match('/^([\+\- ])(.*)/', $line, $matches))
			{
				$action = $matches[1];
				$content = $matches[2];
				
				// leader line
				if ($action == ' ')
				{
					$this->diff[$this->index]['lines'][$this->hunkId][] = array(
						'line'		=> $content,
						'act'		=> '',
						'oldlineno'	=> ++$this->hunkLines['old']['line'],
						'newlineno'	=> ++$this->hunkLines['new']['line']
					);
					
					$delstack = array();
				}
				// addition
				else if ($action == '+')
				{		
					// 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'];
								$change = '{@-' . '-}' . substr($lastline['line'], $delta['start'], $end - $delta['start']) . '{/@-' . '-}';
								$this->diff[$this->index]['lines'][$this->hunkId][$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'];
								$change = '{@+' . '+}' . substr($content, $delta['start'], $end - $delta['start']) . '{/@+' . '+}';
								$content = substr($content, 0, $delta['start']) . $change . substr($content, $end);
							}
						}
					}
					
					$this->diff[$this->index]['lines'][$this->hunkId][] = array(
						'line'		=> $content,
						'act'		=> '+',
						'oldlineno'	=> 0,
						'newlineno'	=> ++$this->hunkLines['new']['line']
					);
				}
				// deletion
				else if ($action == '-')
				{
					$this->diff[$this->index]['lines'][$this->hunkId][] = $temp = array(
						'line'		=> $content,
						'act'		=> '-',
						'oldlineno'	=> ++$this->hunkLines['old']['line'],
						'newlineno'	=> 0
					);
					
					$temp['index'] = sizeof($this->diff[$this->index]['lines'][$this->hunkId]) - 1;
					array_push($delstack, $temp);
				}
			}
		}
	}
	
	// ###################################################################
	/**
	* Processes properties
	*
	* @param	array	Lines of properties
	*/
	private function _processProperties($lines)
	{
		$curprop = '';
		$mode = '';
		$captureStart = 1;
		for ($i = 1; $i < sizeof($lines); $i++)
		{
			$line = $lines[$i];
			if (preg_match('#Name: (.*?)$#', $line, $matches))
			{
				$curprop = $matches[1];
				BSRegister::Debug("prop: $curprop");
			}
			else
			{
				if (preg_match('#^\s+?\+(.*)#', $line, $matches))
				{
					$mode = 'add';
					$this->diff[$this->index]['props'][$curprop]['add'] .= $matches[1];
				}
				else if (preg_match('#^\s+?\-(.*)#', $line, $matches))
				{
					$mode = 'del';
					$this->diff[$this->index]['props'][$curprop]['del'] .= $matches[1];
				}
				else if (!preg_match('#^\s+[\+\- ](.*)#', $line) AND trim($line) != '')
				{
					$this->diff[$this->index]['props'][$curprop][$mode] .= "\n" . $line;
				}
			}
		}
	}
	
	// ###################################################################
	/**
	* 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)
	{
		$start = 0;
		$min = min(strlen($old), strlen($new));
		
		while ($start < $min AND $old[$start] == $new[$start])
		{
			$start++;
		}
		
		$end = -1;
		$min = $min - $start;
		
		while (-$end <= $min AND $old[strlen($old) + $end] == $new[strlen($new) + $end])
		{
			$end--;
		}
		
		return array('start' => $start, 'end' => $end + 1);
	}
}

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