<?php

/**
 * @file
 * Add a field to nodes containing the publication date.
 */

/**
 * Implements hook_node_load().
 */
function publication_date_node_load($nodes, $types) {
  foreach ($nodes as $node) {
    $node->published_at = _publication_date_get_date($node->nid);
  }
}

/**
 * Implements hook_node_insert().
 */
function publication_date_node_insert($node) {
  // Save the publication date.
  _publication_date_set_date($node, 'insert');
}

/**
 * Implements hook_node_update().
 */
function publication_date_node_update($node) {
  // Save the publication date.
  _publication_date_set_date($node, 'update');
}

/**
 * Implements hook_node_delete().
 */
function publication_date_node_delete($node) {
  // Delete the publication date for the deleted node.
  db_delete('publication_date')
    ->condition('nid', $node->nid)
    ->execute();
}

/**
 * Worker function to save the published date to the database.
 *
 * @param object $node
 *   The node object.
 * @param string $op
 *   The node opperation being performed:
 *   - 'insert': a new node was created
 *   - 'update': an existing node was updated
 *
 * @see hook_node_insert()
 * @see hook_node_update()
 */
function _publication_date_set_date($node, $op = '') {
  // Set a default publication date value.
  $published_at = empty($node->published_at) ? 0 : $node->published_at;

  // If no publication date has been set and the node is published then use
  // REQUEST_TIME. Otherwise, use the default publication date.
  $published_at = ($published_at == 0 && $node->status == 1) ? REQUEST_TIME : $published_at;

  // Allow other modules to alter the publication date before it is saved.
  drupal_alter('publication_date', $published_at, $node, $op);

  // Update the node object.
  $node->published_at = $published_at;

  // Save the publication date to the database.
  db_merge('publication_date')
    ->key(array('nid' => $node->nid))
    ->fields(array('published_at' => $published_at))
    ->execute();
}

/**
 * Worker function to get a published date from the database.
 *
 * @param int $nid
 *   The node ID.
 * @return the publication date for the given node, or false if the node is not
 *   published.
 *
 * @see hook_node_load()
 */
function _publication_date_get_date($nid) {
  $date = db_query("SELECT published_at FROM {publication_date} WHERE nid = :nid", array(':nid' => $nid))->fetchField();
  return $date;
}

/**
 * Implements hook_views_api().
 */
function publication_date_views_api() {
  return array(
    'api' => 3,
    'path' => drupal_get_path('module', 'publication_date') . '/includes',
  );
}

/**
 * Implements hook_form_BASE_ID_alter().
 *
 * Display the publication date on the node edit form.
 * @note: This won't work where you have Display Suite/REL enabled.
 */
function publication_date_form_node_form_alter(&$form, &$form_state, $form_id) {
  $node = $form["#node"];

  // If this is an existing node then get the currently set publication date.
  $published_at = ($form['nid'] !== NULL && isset($node->published_at) && $node->published_at) ? $node->published_at : 0;

  // Check if the user has permission to edit the publication date.
  $pubdate_access = user_access('set any published on date') || user_access('set ' . $node->type . ' published on date');

  // Set a date/time format to use in the "Published on" text field.
  $date_format = 'Y-m-d H:i:s O';

  // Use the popup date picker provided by the Date module, if it is enabled and
  // the user has access to edit the publication date.
  if ($pubdate_access && module_exists('date_popup') && variable_get('publication_date_popup_enable', 1)) {
    // The date popup field requires a date format without the timezone.
    $date_format = 'Y-m-d H:i:s';
    $form['options']['pubdate'] = array(
      '#type' => 'date_popup',
      '#title' => t('Published on'),
      '#description' => t('Leave blank to use the time of form submission.'),
      '#date_type' => DATE_UNIX,
      '#date_timezone' => date_default_timezone(),
      '#date_format' => $date_format,
      '#date_increment' => 1,
      '#date_year_range' => '-' . variable_get('publication_date_popup_year_start', '6') . ':+' . variable_get('publication_date_popup_year_end', '1'),
      '#weight' => -1,
      '#access' => TRUE,
    );
  }
  // Falback to a standard text field.
  else {
    $form['options']['pubdate'] = array(
      '#type' => 'textfield',
      '#title' => t('Published on'),
      '#maxlength' => 25,
      '#description' => t('Format: %time. Leave blank to use the time of form submission.', array('%time' => format_date(REQUEST_TIME, 'custom', $date_format))),
      '#weight' => -1,
      '#access' => $pubdate_access,
    );
  }

  // If there is an existing publication date, set it as the default value.
  if (!empty($published_at)) {
    $form['options']['pubdate']['#default_value'] = format_date($published_at, 'custom', $date_format);
  }

  // If the user can access pubdate, we need to make sure they also have access
  // to the options group.
  if ($pubdate_access && $form['options']['#access'] == FALSE) {
    $form['options']['#access'] = TRUE;
    // Check all fields in the options group and, if access has not been set,
    // set it to FALSE. We don't want to grant access to any extra fields.
    $children = element_children($form['options']);
    foreach ($children as $key => $value) {
      if (!isset($form['options'][$value]['#access'])){
        $form['options'][$value]['#access'] = FALSE;
      }
    }
  }

  // Add custom validation and submit handlers.
  $form['#validate'][] = 'publication_date_pubdate_validate';
  $form['#submit'][] = 'publication_date_pubdate_submit';
}

/**
 * Node edit form validation handler.
 *
 * Validate the published date input.
 */
function publication_date_pubdate_validate($form, &$form_state) {
  // Validate the "Published on" field. As of PHP 5.1.0, strtotime returns FALSE
  // instead of -1 upon failure.
  if (!empty($form_state['values']['pubdate']) && strtotime($form_state['values']['pubdate']) <= 0) {
    form_set_error('pubdate', t('You have to specify a valid date for the published on field.'));
  }
}

/**
 * Node edit form submit handler.
 *
 * Convert the published date to Epoch time for other hook implementations to
 * deal with.
 */
function publication_date_pubdate_submit($form, &$form_state) {
  // Set $node->published_at to the publication date field value, if it was set,
  // or zero if it was not.
  $form_state['node']->published_at = empty($form_state['values']['pubdate']) ? 0 : strtotime(($form_state['values']['pubdate']));
}

/**
 * Implements hook_permisson().
 */
function publication_date_permission() {
  $permissions = array(
    'administer publication date' => array(
      'title' => t('Administer publication date'),
      'description' => t('Administer Publication date settings'),
    ),
    'set any published on date' => array(
      'title' => t('Modify any "Published On" date'),
      'description' => t('Change the "Published On" date for any content type.'),
    ),
  );

  // Generate permissions to modify Published On date for all node types.
  foreach (node_permissions_get_configured_types() as $type) {
    $permissions += publication_date_list_permissions($type);
  }

  return $permissions;
}

/**
 * Helper function to generate permission each content type.
 *
 * @param $type
 *   The machine-readable name of the node type.
 * @return
 *   An array of permission names and description.
 */
function publication_date_list_permissions($type) {
  $name = node_type_get_name($type);
  $type = check_plain($type);

  $permissions = array(
    "set $type published on date" => array(
      'title' => t('Modify %type_name "Published On" date.', array('%type_name' => $name)),
      'description' => t('Change the "Published On" date for this content type.'),
    ),
  );

  return $permissions;
}

/**
 * Implements hook_entity_property_info_alter().
 */
function publication_date_entity_property_info_alter(&$info) {
  $properties = &$info['node']['properties'];

  $properties['published_at'] = array(
    'label' => t('Published at'),
    'description' => t('The publication date of the node.'),
    'type' => 'date',
    'getter callback' => '_publication_date_entity_property_getter',
  );
}

/**
 * Publication date getter for hook_entity_property_info_alter()
 *
 * @param $entity
 *   The entity object.
 *
 * @return integer
 *   The publication date as a timestamp get from the entity.
 */
function _publication_date_entity_property_getter($entity) {
  return $entity->published_at;
}

/**
 * Implements hook_clone_node_alter().
 *
 * Reset the publication date when a node is cloned using the Node Clone module.
 *
 * @see clone.api.php
 */
function publication_date_clone_node_alter(&$node, $context) {
  $node->published_at = NULL;
}

/**
 * Implements hook_menu().
 */
function publication_date_menu() {
  $items['admin/config/content/publication-date'] = array(
    'title' => 'Publication date',
    'description' => 'Configure publication date settings when using the date popup module.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('publication_date_admin_form'),
    'access arguments' => array('administer publication date'),
    'file' => 'includes/publication_date.admin.inc',
  );

  return $items;
}