<?php

/**

 * XHTML diff renderer.

 *

 * This class renders diffs in XHTML format.

 *

 * $Horde: framework/Text_Diff/Diff/Renderer/inline.php,v 1.16 2006/01/08 00:06:57 jan Exp $

 *

 * @author  Ciprian Popovici

 * @author  Dan Fuhry

 * @package Text_Diff

 */

class Text_Diff_Renderer_xhtml extends Text_Diff_Renderer {

    /**

     * Number of leading context "lines" to preserve.

     */

    var $_leading_context_lines = 5;

    /**

     * Number of trailing context "lines" to preserve.

     */

    var $_trailing_context_lines = 3;

    /**

     * Prefix for inserted text.

     */

    var $_ins_prefix = "<!-- Start added text -->\n<tr><td style='width: 0px;'>+</td><td class=\"diff-added\" style='width: 100%;'>";

    /**

     * Suffix for inserted text.

     */

    var $_ins_suffix = "</td></tr>\n<!-- End added text -->\n\n";

    /**

     * Prefix for deleted text.

     */

    var $_del_prefix = "<!-- Start deleted text -->\n<tr><td style='width: 0px;'>-</td><td class=\"diff-deleted\" style='width: 100%;'>";

    /**

     * Suffix for deleted text.

     */

    var $_del_suffix = "</td></tr>\n<!-- End deleted text -->\n\n";

    /**

     * Header for each change block.

     */

    var $_block_header = '';

    /**

     * What are we currently splitting on? Used to recurse to show word-level

     * changes.

     */

    var $_split_level = 'lines';

    function _blockHeader($xbeg, $xlen, $ybeg, $ylen)

    {

      return "<!-- Start block -->\n<tr><td colspan='2' class='diff-block'>Line $xbeg: {$this->_block_header}</td></tr>";

    }

    function _startBlock($header)

    {

        return $header;

    }

    function _lines($lines, $prefix = ' ', $encode = true)

    {

        if ($encode) {

            array_walk($lines, array(&$this, '_encode'));

        }

        if ($this->_split_level == 'words') {

            return implode('', $lines);

        } else {

            return implode("<br />", $lines) . "\n";

        }

    }

    function _added($lines)

    {

        array_walk($lines, array(&$this, '_encode'));

        $lines[0] = $this->_ins_prefix . $lines[0];

        $lines[count($lines) - 1] .= $this->_ins_suffix;

        return $this->_lines($lines, ' ', false);

    }

    function _deleted($lines, $words = false)

    {

        array_walk($lines, array(&$this, '_encode'));

        $lines[0] = $this->_del_prefix . $lines[0];

        $lines[count($lines) - 1] .= $this->_del_suffix;

        return $this->_lines($lines, ' ', false);

    }

    function _context($lines)

    {

        return "<!-- Start context -->\n<tr><td></td><td class=\"diff-context\">".$this->_lines($lines).'</td></tr>'."\n<!-- End context -->\n\n";

    }

    function _changed($orig, $final)

    {

        /* If we've already split on words, don't try to do so again - just display. */ 

        if ($this->_split_level == 'words') {

            $prefix = '';

            while ($orig[0] !== false && $final[0] !== false &&

                   substr($orig[0], 0, 1) == ' ' &&

                   substr($final[0], 0, 1) == ' ') {

                $prefix .= substr($orig[0], 0, 1);

                $orig[0] = substr($orig[0], 1);

                $final[0] = substr($final[0], 1);

            }

            $ret = $prefix . $this->_deleted($orig) . $this->_added($final) . "\n";

            //echo 'DEBUG:<pre>'.htmlspecialchars($ret).'</pre>';

            return $ret;

        }

        $text1 = implode("\n", $orig);

        $text2 = implode("\n", $final);

        /* Non-printing newline marker. */

        $nl = "\0";

        /* We want to split on word boundaries, but we need to

         * preserve whitespace as well. Therefore we split on words,

         * but include all blocks of whitespace in the wordlist. */

        $diff = &new Text_Diff($this->_splitOnWords($text1, $nl),

                               $this->_splitOnWords($text2, $nl));

        /* Get the diff in inline format. */

        $renderer = &new Text_Diff_Renderer_inline(array_merge($this->getParams(),

                                                               array('split_level' => 'words')));

        /* Run the diff and get the output. */

        $ret = str_replace($nl, "<br />", $renderer->render($diff));

        //echo 'DEBUG:<pre>'.htmlspecialchars($ret).'</pre>';

        return $ret . "\n";

    }

    function _splitOnWords($string, $newlineEscape = "<br />")

    {

        $words = array();

        $length = strlen($string);

        $pos = 0;

        while ($pos < $length) {

            // Eat a word with any preceding whitespace.

            $spaces = strspn(substr($string, $pos), " \n");

            $nextpos = strcspn(substr($string, $pos + $spaces), " \n");

            $words[] = str_replace("\n", $newlineEscape, substr($string, $pos, $spaces + $nextpos));

            $pos += $spaces + $nextpos;

        }

        return $words;

    }

    function _encode(&$string)

    {

        $string = htmlspecialchars($string);

    }

    /**

     * Renders a diff.

     *

     * @param Text_Diff $diff  A Text_Diff object.

     *

     * @return string  The formatted output.

     */

    function render($diff)

    {

        $xi = $yi = 1;

        $block = false;

        $context = array();

        $nlead = $this->_leading_context_lines;

        $ntrail = $this->_trailing_context_lines;

        $output = $this->_startDiff();

        $diffs = $diff->getDiff();

        foreach ($diffs as $i => $edit) {

            if (is_a($edit, 'Text_Diff_Op_copy')) {

                if (is_array($block)) {

                    $keep = $i == count($diffs) - 1 ? $ntrail : $nlead + $ntrail;

                    if (count($edit->orig) <= $keep) {

                        $block[] = $edit;

                    } else {

                        if ($ntrail) {

                            $context = array_slice($edit->orig, 0, $ntrail);

                            $block[] = &new Text_Diff_Op_copy($context);

                        }

                        $bk = $this->_block($x0, $ntrail + $xi - $x0,

                                            $y0, $ntrail + $yi - $y0,

                                            $block);

                        $output .= $bk;

                        $block = false;

                    }

                }

                $context = $edit->orig;

            } else {

                if (!is_array($block)) {

                    $context = array_slice($context, count($context) - $nlead);

                    $x0 = $xi - count($context);

                    $y0 = $yi - count($context);

                    $block = array();

                    if ($context) {

                        $block[] = &new Text_Diff_Op_copy($context);

                    }

                }

                $block[] = $edit;

            }

            if ($edit->orig) {

                $xi += count($edit->orig);

            }

            if ($edit->final) {

                $yi += count($edit->final);

            }

        }

        if (is_array($block)) {

            $bk = $this->_block($x0, $xi - $x0,

                                $y0, $yi - $y0,

                                $block);

            $output .= $bk;

        }

        $final = $output . $this->_endDiff();

        if ($final == '') $final = '<tr><td class="diff-block">No differences.</td></tr>';

        //$final = preg_replace('#('.preg_quote($this->_ins_suffix).'|'.preg_quote($this->_del_suffix).')(.+?)('.preg_quote($this->_ins_prefix).'|'.preg_quote($this->_ins_suffix).')#', '\\1<tr><td></td><td class="diff-context>\\2</td></tr>\\3', $final);

        return '<table class="diff">'.$final.'</table>'."\n\n";

    }

    function _block($xbeg, $xlen, $ybeg, $ylen, &$edits)

    {

        $output = $this->_startBlock($this->_blockHeader($xbeg, $xlen, $ybeg, $ylen));

        foreach ($edits as $edit) {

            switch (strtolower(get_class($edit))) {

            case 'text_diff_op_copy':

                $output .= $this->_context($edit->orig);

                break;

            case 'text_diff_op_add':

                $output .= $this->_added($edit->final);

                break;

            case 'text_diff_op_delete':

                $output .= $this->_deleted($edit->orig);

                break;

            case 'text_diff_op_change':

                $output .= $this->_changed($edit->orig, $edit->final);

                break;

            }

        }

        return $output . $this->_endBlock();

    }

}