<?php
/**
 * Copyright 2012(c) OBiBa, All rights reserved.
 *
 * This program and the accompanying materials are made available under the terms of the GNU Public License v3.0.
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * Implements hook_block_info().
 *
 * This hook declares what blocks are provided by the module.
 */
function node_reference_block_block_info() {

  $blocks['related-content'] = array(
    'info' => t('Related information'),
    'status' => TRUE,
    'region' => BLOCK_REGION_NONE,
    'visibility' => BLOCK_VISIBILITY_LISTED,
    'pages' => 'node/*',
  );

  return $blocks;
}

/**
 * Implements hook_block_configure().
 */
function node_reference_block_block_configure($delta = '') {

  if ($delta === 'related-content') {
    $form['visibility']['exclude_related_type'] = array(
      '#type' => 'fieldset',
      '#title' => t('Excluded related types'),
      '#collapsible' => TRUE,
      '#collapsed' => TRUE,
      '#group' => 'visibility',
      '#weight' => 6,
      '#attached' => array(
        'js' => array(drupal_get_path('module', 'node_reference_block') . '/node_reference_block.js'),
      ),
    );
    $form['visibility']['exclude_related_type']['related_content_block_exclude'] = array(
      '#type' => 'checkboxes',
      '#title' => t('Excluded related types'),
      '#default_value' => variable_get('related_content_block_exclude', array('pairing')),
      '#options' => node_type_get_names(),
      '#description' => t('Excludes selected types from related information.'),
    );
    return $form;
  }
}

/**
 * Implements hook_block_save().
 */
function node_reference_block_block_save($delta = '', $edit = array()) {
  if ($delta === 'related-content') {
    variable_set('related_content_block_exclude', array_filter($edit['related_content_block_exclude']));
  }
}

/**
 * Implements hook_block_view().
 *
 * This hook generates the contents of the blocks themselves.
 */
function node_reference_block_block_view($delta = '') {
  //The $delta parameter tells us which block is being requested.
  switch ($delta) {
    case 'related-content':
      return _node_reference_block_related_content_block_content();
    default:
      return;
  }
}


/**
 * Related content block content.
 */
function _node_reference_block_related_content_block_content() {

  $exclude_types = variable_get('related_content_block_exclude', array('pairing'));

  if (strpos($_GET['q'], 'node/') === 0) {
    $node_path = explode('/', $_GET['q']);
    if (array_key_exists(1, $node_path) && is_numeric($node_path[1])) {
      $node = node_load($node_path[1]);
      $related_content = array();

      // look for nodes refering the current node
      $query = db_select('field_config', 'f')
        ->fields('f', array('field_name'))
        ->condition('f.type', 'node_reference', '=')
        ->condition('f.deleted', FALSE, '=');

      $result = $query->execute();
      while ($record = $result->fetchAssoc()) {
        $field_name = $record['field_name'];
        $q = db_select('field_data_' . $field_name, 'f')
          ->fields('f', array('entity_id'))
          ->condition('f.deleted', FALSE, '=')
          ->condition('f.' . $field_name . '_nid', $node->nid, '=');
        $res = $q->execute();

        while ($rec = $res->fetchAssoc()) {
          $related_node = node_load($rec['entity_id']);

          if (in_array($related_node->type, $exclude_types)) continue;

          if (node_access('view', $related_node)) {
            $node_type = node_type_load($related_node->type);
            if (!array_key_exists($node_type->name, $related_content)) {
              $related_content[$node_type->name] = array();
            }
            $related_content[$node_type->name][$related_node->title] = $related_node->nid;
          }
        }
      }

      // look for nodes referred by the current node
      $query = db_select('field_config', 'f');
      $query->join('field_config_instance', 'fi', 'f.id = fi.field_id');
      $query->fields('f', array('field_name'))
        ->condition('f.type', 'node_reference', '=')
        ->condition('f.deleted', FALSE, '=')
        ->condition('fi.bundle', $node->type, '=');

      $result = $query->execute();

      while ($record = $result->fetchAssoc()) {
        $field_name = $record['field_name'];
        $field = $node->$field_name;

        $field_info = field_info_instance('node', $field_name, $node->type);

        $related_content[$field_info['label']] = array();
        if (array_key_exists(LANGUAGE_NONE, $field)) {
          $values = $field[LANGUAGE_NONE];
          if ($values) {
            foreach ($values as $val) {
              $related_node = node_load($val['nid']);
              // displays only published related content (language independent)
              if (node_access('view', $related_node) && $related_node->status == NODE_PUBLISHED) {
                $related_content[$field_info['label']][$related_node->title] = $related_node->nid;
              }
            }
          }
        }
      }

      if (empty($related_content)) {
        return;
      }

      $content = '<ul>';
      foreach ($related_content as $group => $relations) {
        if (!empty($relations)) {
          $content .= '<li>' . t($group) . '<ul>';
          foreach ($relations as $title => $nid) {
            $content .= '<li>' . l(t($title), 'node/' . $nid) . '</li>';
          }
          $content .= '</ul></li>';
        }
      }
      $content .= '</ul>';

      $block['subject'] = t('Related information');
      $block['content'] = $content;

      return $block;
    }
  }
  return;
}