<?php

/**
 * Implementation of hook_form_alter(). Menu Settings for Content Type.
 */
function ctm_form_alter(&$form, $form_state, $form_id) {
  // Menu Setting for content types - Content Type Form
  if ($form_id == 'node_type_form') {
    $form['menu_settings'] = array(
	  '#type' => 'fieldset',
	  '#title' => t('Menu Settings'),
	  '#description' => t('Enable Menu Settings for this content type.'),
	  '#collapsible' => TRUE,
    );
	$default_values = variable_get($form['#node_type']->type.'_menu_settings', array());
	//$default_values = $default_values ? $default_values : array();
	$options = menu_get_menus();
	$form['menu_settings']['menu'] = array(
      '#type' => 'checkboxes',
      '#title' => t('Enable the Menus you want to be available for this Content Type'),
	  '#default_value' => $default_values,
	  '#options' => $options,
    );  
	$form['#submit'][] = 'ctm_node_type_form_submit';
  }
  // Menu Settings for Node Edit (Form)
  elseif (isset($form['#node']) && $form['#node']->type .'_node_form' == $form_id) {
    $menu_settings = variable_get($form['#node']->type.'_menu_settings', array());
	if ($menu_settings) {
	  $menus = array_intersect_key(menu_get_menus(), $menu_settings);
	  $options = menu_parent_options($menus, $form['menu']['#item']);
	  $form['menu']['parent']['#options'] = $options;
	} else {
	    unset($form['menu']);
    }
  }
  // Delete Content Type
  elseif ($form_id == 'node_type_delete_confirm') {
    $form['#submit'][] = 'ctm_node_type_delete_confirm';
  }
}

/**
 *  Content Type Form Submit - Save Menu Settings for Content Type. 
 */
function ctm_node_type_form_submit(&$form, $form_state) {
  $menu_settings = array_filter($form_state['values']['menu']);
  if ($menu_settings) {
     variable_set($form_state['values']['type'].'_menu_settings', $menu_settings);
  } else {
     variable_del($form_state['values']['type'].'_menu_settings');
  }
}

/**
 *  Delete Content Type Form Submit - Delete Menu Settings Variable. 
 */
function ctm_node_type_delete_confirm(&$form, $form_state) {
  variable_del($form_state['values']['type'].'_menu_settings');
}