<?php
// $Id: diff.module,v 1.2.2.3 2005/05/05 18:20:37 weitzman Exp $

/*
 * Diff module for drupal.
 * Copyright (c) 2005 Mohammed Sameer.
 * Significantly updated and maintained by Moshe Weitzman <weitzman [at] tejasa DOT com>
 * This module is distributed under the GPL.
*/

include_once 'Text/Diff.php';
include_once 'Text/Diff/Renderer.php';
include_once 'Text/Diff/Renderer/inline.php';

function diff_help($section) {
  switch ($section) {
  case 'admin/help#diff':
  case 'admin/modules#description':
  case 'admin/diff':
    return "Show difference between node revisions.";
  }
}

/**
 * Implementation of hook_perm().
 */
function diff_perm() {
  return array('access diff');
}

/**
 * Implementation of hook_menu().
 */
function diff_menu($may_cache)
{
  $items = array();

  //if (!$may_cache) {
    if (arg(0) == 'node' && is_numeric(arg(1))) {
      $node = node_load(arg(1));
      if ($node->nid)	{
        if ( count(node_revision_list($node)) > 1 ) {
           $items[] = array('path' => 'node/'. arg(1) .'/diff', 'title' => t('diff'),
           'callback' => 'diff_page',
           'callback arguments' => arg(1),
           'access' => user_access('access diff'),
           'weight' => 6,
           'type' => MENU_LOCAL_TASK);
        }
      }
    }
    $path = drupal_get_path('module', 'diff');
    $style = "<link type=\"text/css\" rel=\"stylesheet\" href=\"$path/diff.css\" />";
    drupal_set_html_head($style);
  //}
  return $items;
}

/**
 * Show a difference between revisions.
 */
function diff_page($nid, $rid1 = NULL, $rid2 = NULL) {
  if (!is_null($rid1)) {
    return _diff_show_revision($nid, $rid1, $rid2);
  }
  else {
    return _diff_show_page($nid);
  }
}


function _diff_show_revision($nid, $rid1, $rid2 = NULL) {
  $r1 = node_load($nid, $rid1);
  $r2 = node_load($nid, $rid2);
  $source = explode("\n", diff_node_render($r2));
  $target = explode("\n", diff_node_render($r1));
  $diff = &new Text_Diff($source, $target);
  $renderer = &new Text_Diff_Renderer_inline();
  $node = $r1;
  $node->body = $renderer->render($diff); 
  return theme('node', $node);
}

function _diff_show_page($nid) {
  $node = node_load($nid);
  drupal_set_title($node->title);

  $header = array(t('Older revisions'), array('data' => t('Operations'), 'colspan' => 3));
  // $last_key = count($node->revisions) - 1;
	
	$revisions = node_revision_list($node);

  foreach ($revisions as $key => $revision)	{
		$vid = $revision->vid;
    if ($key != 0) {
      $prev = l(t('previous'), "node/$node->nid/diff/$vid/".( $revisions[$key-1]->vid ));
      $first = l(t('first'), "node/$node->nid/diff/$vid/" .($revisions[0]->vid));
    }
    $current = l(t('current'), "node/$node->nid/diff/$vid");
    $rows[] = array(
								t('revision %r (%v) revised by %u on %d',
  								array(
										'%r' => 1 + $key,
    								'%v' => $vid,
    								'%u' => theme('username', user_load(array('uid' => $revision->uid))),
    								'%d' => format_date($revision->timestamp, 'small')
									)
								)
  							. ($revision->history ? '<br /><small>'. $revision->history .'</small>' : ''),
								$prev, $first, $current);
  }
  return theme('table', $header, $rows);
}

// Get node *body* output (filtered and with module-specific fields). Modified from node_update_index()
// return HTML
function diff_node_render($node) {
  if (node_hook($node, 'view')) {
    node_invoke($node, 'view', false, false);
  }
  else {
    $node = node_prepare($node, false);
  }
  // Allow modules to change $node->body before viewing.
  node_invoke_nodeapi($node, 'view', false, false);
  return $node->body;
}

?>