<?php

class Text_Diff {

    
    var $_edits;

    
    function __construct( $engine, $params )
    {
        // Backward compatibility workaround.
        if (!is_string($engine)) {
            $params = array($engine, $params);
            $engine = 'auto';
        }

        if ($engine == 'auto') {
            $engine = extension_loaded('xdiff') ? 'xdiff' : 'native';
        } else {
            $engine = basename($engine);
        }

        // WP #7391
        require_once dirname(__FILE__).'/Diff/Engine/' . $engine . '.php';
        $class = 'Text_Diff_Engine_' . $engine;
        $diff_engine = new $class();

        $this->_edits = call_user_func_array(array($diff_engine, 'diff'), $params);
    }

	
	public function Text_Diff( $engine, $params ) {
		self::__construct( $engine, $params );
	}

    
    function getDiff()
    {
        return $this->_edits;
    }

    
    function countAddedLines()
    {
        $count = 0;
        foreach ($this->_edits as $edit) {
            if (is_a($edit, 'Text_Diff_Op_add') ||
                is_a($edit, 'Text_Diff_Op_change')) {
                $count += $edit->nfinal();
            }
        }
        return $count;
    }

    
    function countDeletedLines()
    {
        $count = 0;
        foreach ($this->_edits as $edit) {
            if (is_a($edit, 'Text_Diff_Op_delete') ||
                is_a($edit, 'Text_Diff_Op_change')) {
                $count += $edit->norig();
            }
        }
        return $count;
    }

    
    function reverse()
    {
        if (version_compare(zend_version(), '2', '>')) {
            $rev = clone($this);
        } else {
            $rev = $this;
        }
        $rev->_edits = array();
        foreach ($this->_edits as $edit) {
            $rev->_edits[] = $edit->reverse();
        }
        return $rev;
    }

    
    function isEmpty()
    {
        foreach ($this->_edits as $edit) {
            if (!is_a($edit, 'Text_Diff_Op_copy')) {
                return false;
            }
        }
        return true;
    }

    
    function lcs()
    {
        $lcs = 0;
        foreach ($this->_edits as $edit) {
            if (is_a($edit, 'Text_Diff_Op_copy')) {
                $lcs += count($edit->orig);
            }
        }
        return $lcs;
    }

    
    function getOriginal()
    {
        $lines = array();
        foreach ($this->_edits as $edit) {
            if ($edit->orig) {
                array_splice($lines, count($lines), 0, $edit->orig);
            }
        }
        return $lines;
    }

    
    function getFinal()
    {
        $lines = array();
        foreach ($this->_edits as $edit) {
            if ($edit->final) {
                array_splice($lines, count($lines), 0, $edit->final);
            }
        }
        return $lines;
    }

    
    static function trimNewlines(&$line, $key)
    {
        $line = str_replace(array("\n", "\r"), '', $line);
    }

    
    static function _getTempDir()
    {
        $tmp_locations = array('/tmp', '/var/tmp', 'c:\WUTemp', 'c:\temp',
                               'c:\windows\temp', 'c:\winnt\temp');

        /* Try PHP's upload_tmp_dir directive. */
        $tmp = ini_get('upload_tmp_dir');

        /* Otherwise, try to determine the TMPDIR environment variable. */
        if (!strlen($tmp)) {
            $tmp = getenv('TMPDIR');
        }

        /* If we still cannot determine a value, then cycle through a list of
         * preset possibilities. */
        while (!strlen($tmp) && count($tmp_locations)) {
            $tmp_check = array_shift($tmp_locations);
            if (@is_dir($tmp_check)) {
                $tmp = $tmp_check;
            }
        }

        /* If it is still empty, we have failed, so return false; otherwise
         * return the directory determined. */
        return strlen($tmp) ? $tmp : false;
    }

    
    function _check($from_lines, $to_lines)
    {
        if (serialize($from_lines) != serialize($this->getOriginal())) {
            throw new Text_Exception("Reconstructed original does not match");
        }
        if (serialize($to_lines) != serialize($this->getFinal())) {
            throw new Text_Exception("Reconstructed final does not match");
        }

        $rev = $this->reverse();
        if (serialize($to_lines) != serialize($rev->getOriginal())) {
            throw new Text_Exception("Reversed original does not match");
        }
        if (serialize($from_lines) != serialize($rev->getFinal())) {
            throw new Text_Exception("Reversed final does not match");
        }

        $prevtype = null;
        foreach ($this->_edits as $edit) {
            if ($prevtype !== null && $edit instanceof $prevtype) {
                throw new Text_Exception("Edit sequence is non-optimal");
            }
            $prevtype = get_class($edit);
        }

        return true;
    }

}


class Text_MappedDiff extends Text_Diff {

    
    function __construct($from_lines, $to_lines,
                             $mapped_from_lines, $mapped_to_lines)
    {
        assert(count($from_lines) == count($mapped_from_lines));
        assert(count($to_lines) == count($mapped_to_lines));

        parent::Text_Diff($mapped_from_lines, $mapped_to_lines);

        $xi = $yi = 0;
        for ($i = 0; $i < count($this->_edits); $i++) {
            $orig = &$this->_edits[$i]->orig;
            if (is_array($orig)) {
                $orig = array_slice($from_lines, $xi, count($orig));
                $xi += count($orig);
            }

            $final = &$this->_edits[$i]->final;
            if (is_array($final)) {
                $final = array_slice($to_lines, $yi, count($final));
                $yi += count($final);
            }
        }
    }

	
	public function Text_MappedDiff( $from_lines, $to_lines,
                             $mapped_from_lines, $mapped_to_lines ) {
		self::__construct( $from_lines, $to_lines,
                             $mapped_from_lines, $mapped_to_lines );
	}

}


abstract class Text_Diff_Op {

    var $orig;
    var $final;

    abstract function &reverse();

    function norig()
    {
        return $this->orig ? count($this->orig) : 0;
    }

    function nfinal()
    {
        return $this->final ? count($this->final) : 0;
    }

}


class Text_Diff_Op_copy extends Text_Diff_Op {

	
    function __construct( $orig, $final = false )
    {
        if (!is_array($final)) {
            $final = $orig;
        }
        $this->orig = $orig;
        $this->final = $final;
    }

	
	public function Text_Diff_Op_copy( $orig, $final = false ) {
		self::__construct( $orig, $final );
	}

    function &reverse()
    {
        $reverse = new Text_Diff_Op_copy($this->final, $this->orig);
        return $reverse;
    }

}


class Text_Diff_Op_delete extends Text_Diff_Op {

	
	function __construct( $lines )
    {
        $this->orig = $lines;
        $this->final = false;
    }

	
	public function Text_Diff_Op_delete( $lines ) {
		self::__construct( $lines );
	}

    function &reverse()
    {
        $reverse = new Text_Diff_Op_add($this->orig);
        return $reverse;
    }

}


class Text_Diff_Op_add extends Text_Diff_Op {

	
    function __construct( $lines )
    {
        $this->final = $lines;
        $this->orig = false;
    }

	
	public function Text_Diff_Op_add( $lines ) {
		self::__construct( $lines );
	}

    function &reverse()
    {
        $reverse = new Text_Diff_Op_delete($this->final);
        return $reverse;
    }

}


class Text_Diff_Op_change extends Text_Diff_Op {

	
    function __construct( $orig, $final )
    {
        $this->orig = $orig;
        $this->final = $final;
    }

	
	public function Text_Diff_Op_change( $orig, $final ) {
		self::__construct( $orig, $final );
	}

    function &reverse()
    {
        $reverse = new Text_Diff_Op_change($this->final, $this->orig);
        return $reverse;
    }

}