<?php
/**
 * @file
 * Defines date-related Views data and plugins:
 *
 * Date argument:
 *   A generic date argument that has an option to select one or more
 *   Views date fields to filter on, automatically adds them to the view,
 *   and then filters the view by the value of the selected field(s).
 *   The flexible argument will accept and evaluate most ISO date
 *   and period formats, like 2009-05-01, 2008-W25, P1W.
 *
 * Date filter:
 *   A generic date filter that has an option to select a
 *   Views date field to filter on, with a choice of a widget to use
 *   for the filter form and an option to set the default value to
 *   a set date or something like 'now +90 days' . If the operator is
 *   set to 'between' or 'not between' you can set a default value for
 *   both the start and end dates.
 *
 * Current date argument default
 *   Adds a default option to set the argument to the current date
 *   when the argument is empty.
 *
 * Date navigation attachment
 *   Navigation that can be attached to any display to create back/next
 *   links by date, requires the date argument and uses the current
 *   date argument default to set a starting point for the view.
 */

/**
 * Implements hook_views_plugins().
 */
function date_views_views_plugins() {
  $path = drupal_get_path('module', 'date_views');
  $views_path = drupal_get_path('module', 'views');
  module_load_include('inc', 'date_views', 'theme/theme');

  return array(
    // This just tells our themes are elsewhere.
    'module' => 'date_views',
    'display' => array(
      // Display plugin for date navigation.
      'date_nav' => array(
        'title' => t('Date browser'),
        'help' => t('Date back/next navigation to attach to other displays. Requires the Date argument.'),
        'handler' => 'date_plugin_display_attachment',
        'parent' => 'attachment',
        'path' => "$path/includes",
        'theme' => 'views_view',
        'use ajax' => TRUE,
        'admin' => t('Date browser'),
        'help topic' => 'date-browser',
      ),
    ),

    'pager' => array(
      'date_views_pager' => array(
        'title' => t('Page by date'),
        'help' => t('Page using the value of a date field.'),
        'handler' => 'date_views_plugin_pager',
        'path' => "$path/includes",
        'help topic' => 'date-views-pager',
        'uses options' => TRUE,
      ),
    ),

    'style' => array(
      'date_nav' => array(
        'title' => t('Date browser style'),
        'help' => t('Creates back/next navigation.'),
        'handler' => 'date_navigation_plugin_style',
        'path' => "$path/includes",
        'theme' => 'date_navigation',
        'theme file' => 'theme.inc',
        'theme path' => "$path/theme",
        'uses row plugin' => FALSE,
        'uses fields' => FALSE,
        'uses options' => TRUE,
        'type' => 'date_nav',
        'even empty' => TRUE,
      ),
    ),
  );
}

/**
 * Implements hook_views_data().
 */
function date_views_views_data() {
  $data = array();

  $tables = date_views_base_tables();

  foreach ($tables as $base_table => $entity) {
    // The flexible date argument.
    $data[$base_table]['date_argument'] = array(
      'group' => t('Date'),
      'title' => t('Date (!base_table)', array('!base_table' => $base_table)),
      'help' => t('Filter any Views !base_table date field by a date argument, using any common ISO date/period format (i.e. YYYY, YYYY-MM, YYYY-MM-DD, YYYY-W99, YYYY-MM-DD--P3M, P90D, etc).', array('!base_table' => $base_table)),
      'argument' => array(
        'handler' => 'date_views_argument_handler',
        'empty field name' => t('Undated'),
        'is date' => TRUE,
        // 'skip base' => $base_table,
      ),
    );
    // The flexible date filter.
    $data[$base_table]['date_filter'] = array(
      'group' => t('Date'),
      'title' => t('Date (!base_table)', array('!base_table' => $base_table)),
      'help' => t('Filter any Views !base_table date field.', array('!base_table' => $base_table)),
      'filter' => array(
        'handler' => 'date_views_filter_handler',
        'empty field name' => t('Undated'),
        'is date' => TRUE,
        // 'skip base' => $base_table,
      ),
    );
  }

  return $data;
}

/**
 * Implements hook_views_data_alter().
 */
function date_views_views_data_alter(&$data) {

  // Mark all the core date handlers as date fields.
  // This will identify all handlers that directly use the _date handlers,
  // will not pick up any that extend those handlers.
  foreach ($data as $base_table => &$table) {
    foreach ($table as $id => &$field) {
      foreach (array('field', 'sort', 'filter', 'argument') as $type) {
        if (isset($field[$type]) && isset($field[$type]['handler']) && ($field[$type]['handler'] == 'views_handler_' . $type . '_date')) {
          $field[$type]['is date'] = TRUE;
        }
      }
    }
  }
}

/**
 * Central function for setting up the right timezone values.
 *
 * In the SQL date handler.
 *
 * The date handler will use this information to decide if the
 * database value needs a timezone conversion.
 *
 * In Views, we will always be comparing to a local date value,
 * so the goal is to convert the database value to the right
 * value to compare to the local value.
 */
function date_views_set_timezone(&$date_handler, &$view, $field) {
  switch ($field['tz_handling']) {
    case 'date':
      $date_handler->db_timezone = 'UTC';
      $date_handler->local_timezone_field = $field['timezone_field'];
      $date_handler->offset_field = $field['offset_field'];
      break;

    case 'none':
      $date_handler->db_timezone = date_default_timezone();
      $date_handler->local_timezone = date_default_timezone();
      break;

    case 'utc':
      $date_handler->db_timezone = 'UTC';
      $date_handler->local_timezone = 'UTC';
      break;

    default:
      $date_handler->db_timezone = 'UTC';
      $date_handler->local_timezone = date_default_timezone();
      break;
  }
}

/**
 * Helper function to generate a query string.
 *
 * @param object $view
 *   A View object.
 *
 * @param array $extra_params
 *   An extra parameters.
 *
 * @return null/string
 *   Return a query or NULL.
 */
function date_views_querystring($view, $extra_params = array()) {
  $query_params = array_merge($_GET, $extra_params);
  // Allow NULL params to be removed from the query string.
  foreach ($extra_params as $key => $value) {
    if (!isset($value)) {
      unset($query_params[$key]);
    }
  }
  // Filter the special "q" and "view" variables out of the query string.
  $exclude = array('q');
  // If we don't explicitly add a value for "view", filter it out.
  if (empty($extra_params['view'])) {
    $exclude[] = 'view';
  }
  // Clear out old date pager settings if not explicitly added.
  if (!empty($view->date_info->pager_id) && empty($extra_params[$view->date_info->pager_id])) {
    $exclude[] = $view->date_info->pager_id;
  }

  $query = drupal_get_query_parameters($query_params, $exclude);
  // To prevent an empty query string from adding a "?" on to the end of a URL,
  // we return NULL.
  return !empty($query) ? $query : NULL;
}