<?php

/**
 * Implementation of hook_perm().
 */
function diff_revision_perm() {
  
  return array('view diff revision');
  
}

/**
 * Implementation of hook_menu().
 */
function diff_revision_menu() {
  
  $items = array();
  $items['admin/settings/diff_revision'] = array(
    'title'            => t('Diff revision'),
    'description'      => t('Select type content, which will available for compare the revisions node and etc.'),
    'page callback'    => 'drupal_get_form',
    'page arguments'   => array('diff_revision_settings'),
    'access arguments' => array('diff_revision settings')
  );
  return $items;
  
}

/**
 * Callback function for form the settings
 */
function diff_revision_settings() {
  
  $form      = array();
  $get_types = node_get_types();
  
  foreach($get_types as $key => $value) {
    $types[$key] = $value->name;
  }
  
  $form['diff_revision_type'] = array(
    '#type'          => 'checkboxes',
    '#title'         => t('Type node'),
    '#default_value' => variable_get('diff_revision_type', array()),
    '#options'       => $types,
    '#description'   => t('Tick type node for lighting changes.'),
  );
  
  $form['diff_revision_type_mode'] = array(
    '#type'          => 'radios',
    '#title'         => t('Type mode'),
    '#default_value' => variable_get('diff_revision_type_mode', 2),
    '#options'       => array(
  							'0' => t('When update'),
                    		'1' => t('Count'),
                    		'2' => t('Always'),
  	                    ),
    '#description'   => t('Chose mode for view diff a revisions.'),
  );
  
  $form['diff_revision_type_mode_count'] = array(
    '#type'          => 'textfield',
    '#title'         => t('Count day for type mode "Count"'),
    '#default_value' => variable_get('diff_revision_type_mode_count', 2),
    '#description'   => t('If you selected mode "count", then you must enter number a repeates.'),
  );
  
  return system_settings_form($form);
  
}

function diff_revision_nodeapi(&$node, $op) {
  
  global $user;
  
  if($op == 'view' && user_access('view diff revision') && in_array($node->type, variable_get('diff_revision_type', array()))) {
    
	$access = 0;
	//mode - show always
	if(variable_get('diff_revision_type_mode', '2') == 2) {
	  $access = 1;
	}
	
	//mode - show "n" days
	if(variable_get('diff_revision_type_mode', '1') == 1 && $node->changed > (time() - variable_get('diff_revision_type_mode_count', 2) * 86400)) {
	  $access = 1;
	}
	
	//mode - show if new version or updated
	if(variable_get('diff_revision_type_mode', '0') == 0 && node_mark($node->nid, $node->changed) == MARK_UPDATED) {
	  $access = 1;
	}
	
	//access denied, then not show
  	if(!$access) 
  	  return;
  	
  	$body = db_result(db_query ("SELECT body FROM {node_revisions} WHERE nid = %d AND vid != %d ORDER BY timestamp DESC", $node->nid, $node->vid));
  	
  	if($body) {
  	  drupal_add_css(drupal_get_path('module', 'diff_revision').'/diff_revision.css');
  	  $PATH_TO_LIB_TEXT = drupal_get_path('module', 'diff_revision');
  	  require_once 'daisydiff/src/HTMLDiff.php';
  	  $diff                            = new HTMLDiffer();
  	  $node->content['body']['#value'] = $diff->htmlDiff($body, $node->body);
  	}
  	
  }
  
}