<?php

/**
 * @file
 * Defines a date element that allows for any combination of date granularity
 * settings.
 *
 * Some of the core time handling code was inspired by the zend framework's
 * Zend_Date class:
 *
 * @see
 * http://framework.zend.com/code/filedetails.php?repname=Zend+Framework&path=%2Ftrunk%2Flibrary%2FZend%2FDate%2FDateObject.php&peg=22321
 */

/**
 * TODO, account for that fact that there is no year 0 in the Gregorian calendar
 *  AD 1 = year 1, 1 BC = year 0, 2 BC = year −1,
 */

/**
 * Implements hook_menu().
 */
function partial_date_menu() {
  $counter = 0;
  foreach (partial_date_format_types() as $type => $label) {
    if (!$counter) {
      $items['admin/config/regional/date-time/partial-date-formats'] = array(
        'title' => t('Partial date formats'),
        'page callback' => 'drupal_get_form',
        'page arguments' => array('partial_date_format_settings_form', $type),
        'access arguments' => array('administer site configuration'),
        'type' => MENU_LOCAL_TASK,
        'file' => 'partial_date.pages.inc',
      );
      $items['admin/config/regional/date-time/partial-date-formats/' . $type] = array(
        'title' => $label,
        'type' => MENU_DEFAULT_LOCAL_TASK,
        'weight' => $counter++,
      );
    }
    else {
      $items['admin/config/regional/date-time/partial-date-formats/' . $type] = array(
        'title' => $label,
        'page callback' => 'drupal_get_form',
        'page arguments' => array('partial_date_format_settings_form', $type),
        'access arguments' => array('administer site configuration'),
        'type' => $counter ? MENU_LOCAL_TASK : MENU_DEFAULT_LOCAL_TASK,
        'file' => 'partial_date.pages.inc',
        'weight' => $counter++,
      );
    }
  }
  return $items;
}

################################################################################
#                                                                              #
#  Field API Hooks & Helpers: Fields                                           #
#                                                                              #
#  --------------------------------------------------------------------------  #
#                                                                              #
#  Implements:                                                                 #
#   * hook_field_info()                                                        #
#   * hook_field_settings_form()                                               #
#   * hook_field_instance_settings_form()                                      #
#   * hook_field_load()                                                        #
#   * hook_field_validate()                                                    #
#   * hook_field_is_empty()                                                    #
#   * hook_field_presave()                                                     #
#                                                                              #
#  Helpers:                                                                    #
#   * partial_date_field_estimates_default_settings()                          #
#                                                                              #
#     Provides the default lists for some of the date range lists.             #
#                                                                              #
#   * partial_date_field_estimates_settings_form()                             #
#                                                                              #
#     Shared field and instance FAPI elements for for date range lists.        #
#                                                                              #
#   * partial_date_field_estimates_validate_parse_options()                    #
#                                                                              #
#     Shared field and instance setting for for date component range lists.    #
#                                                                              #
#   * partial_date_field_estimates()                                           #
#                                                                              #
#     Helper function to load the estimate options from the field              #
#                                                                              #
#   * partial_date_field_populate_components()                                 #
#                                                                              #
#     Helper for hook_field_presave() to populate any missing values prior to  #
#     generating the float date value estimates. (The fake timestamp columns). #
#                                                                              #
#   * partial_date_field_presave_generate_storage_date()                       #
#                                                                              #
#     Helper for hook_field_presave() to ensure that all of the columns are    #
#     set in the correct position and names for the storage engine.            #
#                                                                              #
#   * partial_date_field_validate_year()                                       #
#                                                                              #
#     Helper for hook_field_validate() to test that the year in within range.  #
#                                                                              #
################################################################################

/**
 * Implements hook_field_info().
 */
function partial_date_field_info() {
  module_load_include('admin.inc', 'partial_date');
  return _partial_date_field_info();
}

/**
 * Implements hook_field_settings_form().
 */
function partial_date_field_settings_form($field, $instance, $has_data) {
  module_load_include('admin.inc', 'partial_date');
  // Badly name, includes minimal components too.
  return partial_date_field_estimates_settings_form($field['settings'], $field, $instance, $has_data);
}

/**
 * Implements hook_field_load().
 */
function partial_date_field_load($entity_type, $entities, $field, $instances, $langcode, &$items, $age) {
  $has_range = strpos($field['type'], '_range');
  $estimates = partial_date_field_estimates($field);

  foreach ($entities as $id => $entity) {
    foreach ($items[$id] as $delta => &$item) {
      $settings = $instances[$id]['widget']['settings'];

      // Generate a cleaner array based storage of the values.
      $item['data'] = empty($item['data']) ? array() : unserialize($item['data']);

      $item['from'] = array();
      if ($has_range) {
        $item['to'] = array();
      }
      $item['check_approximate'] = empty($item['data']['check_approximate']) ? 0 : 1;

      foreach (partial_date_components() as $key => $title) {
        $item['from'][$key] = $item[$key];
        // Clear auto-populated estimate values.
        if (!empty($item['data'][$key . '_estimate_from_used'])) {
          $item['from'][$key] = '';
        }

        unset($item[$key]);
        if ($key != 'timezone') {
          $item['from'][$key . '_estimate'] = isset($item['data'][$key . '_estimate']) ? $item['data'][$key . '_estimate'] : '';
          _partial_date_expand_estimate($key, $item['from'], $estimates);
        }
        if ($has_range) {
          $item['to'][$key] = $item[$key . '_to'];
          unset($item[$key . '_to']);
          // Clear auto-populated estimate values.
          if (!empty($item['data'][$key . '_estimate_to_used'])) {
            $item['to'][$key] = '';
          }

          if ($key != 'timezone') {
            $item['to'][$key . '_estimate'] = isset($item['data'][$key . '_to_estimate']) ? $item['data'][$key . '_to_estimate'] : '';
            _partial_date_expand_estimate($key, $item['to'], $estimates, FALSE);
          }
        }
      }
    }
  }
}

function _partial_date_expand_estimate($key, &$item, $estimates, $is_start = TRUE) {
  $item[$key . '_estimate_label'] = '';
  $item[$key . '_estimate_value'] = NULL;

  $value = $item[$key . '_estimate'];
  if (!empty($value)) {
    if (!empty($estimates[$key][$value])) {
      $item[$key . '_estimate_label'] = $estimates[$key][$value];
    }
    list($start, $end) = explode('|', $value);
    $item[$key . '_estimate_value'] = $is_start ? $start : $end;
  }
}

/**
 * Helper function to load the estimate options from the field or instance
 * settings.
 */
function partial_date_field_estimates($field) {
  if (!empty($field['settings']['estimates'])) {
    return $field['settings']['estimates'];
  }
  return FALSE;
}

/**
 * Implements hook_field_presave().
 */
function partial_date_field_presave($entity_type, $entity, $field, $instance, $langcode, &$items) {
  module_load_include('admin.inc', 'partial_date');
  _partial_date_field_presave($entity_type, $entity, $field, $instance, $langcode, $items);
}

/**
 * Implements hook_field_validate().
 *
 * Possible error codes:
 * - 'xxxx': The partial_date year is not valid
 *
 * @see partial_date_field_widget_error().
 */
function partial_date_field_validate($obj_type, $object, $field, $instance, $langcode, $items, &$errors) {
  module_load_include('admin.inc', 'partial_date');
  _partial_date_field_validate($obj_type, $object, $field, $instance, $langcode, $items, $errors);
}

/**
 * Implements hook_field_is_empty().
 */
function partial_date_field_is_empty($item, $field) {
  if ((isset($item['_remove']) && $item['_remove']) || !is_array($item)) {
    return TRUE;
  }
  foreach (array('from', 'to') as $base) {
    if (empty($item[$base])) {
      continue;
    }
    foreach (partial_date_components() as $key => $label) {
      if ($key == 'timezone') {
        continue;
      }
      if (isset($item[$base][$key]) && strlen($item[$base][$key])) {
        return FALSE;
      }
      if (isset($item[$base][$key . '_estimate']) && strlen($item[$base][$key . '_estimate'])) {
        return FALSE;
      }
    }
  }

  return !((isset($item['txt_short']) && strlen($item['txt_short'])) ||
         (isset($item['txt_long']) && strlen($item['txt_long'])));
}

################################################################################
#  ---------------------------------                                           #
#  Field API Hooks & Helpers: Widget                                           #
#  ---------------------------------                                           #
#                                                                              #
#  Implements:                                                                 #
#   * hook_field_widget_info()                                                 #
#   * hook_field_widget_settings_form()                                        #
#   * hook_field_widget_form()                                                 #
#   * hook_field_widget_error()                                                #
#                                                                              #
#  Helpers:                                                                    #
#   * partial_date_field_widget_reduce_date_components()                                             #
#     This reduces all possible widget components into a singular array of     #
#     components. Returns FALSE if empty.                                      #
#                                                                              #
################################################################################

/**
 * Implements hook_field_widget_info().
 */
function partial_date_field_widget_info() {
  return array(
    'partial_date' => array(
      'label' => t('Partial date'),
      'field types' => array('partial_date', 'partial_date_range'),
      'settings' => array(
        'tz_handling' => 'none',
        'theme_overrides' => array(
          'check_approximate' => 0,
          'txt_short' => 0,
          'txt_long' => 0,
          'range_inline' => 0,
        ),
        'granularity' => array(
          'from' => drupal_map_assoc(array_keys(partial_date_components())),
          'to' => drupal_map_assoc(array_keys(partial_date_components())),
        ),
        'estimates' => array(
          'from' => array_combine(array_keys(partial_date_components(array('timezone'))), array_fill(0, 6, '')),
          'to' => array_combine(array_keys(partial_date_components(array('timezone'))), array_fill(0, 6, '')),
        ),
        'increments' => array(
          'second' => 1,
          'minute' => 1,
        ),
        'hide_remove' > 0,
        // @todo: i18n support here.
        'help_txt' => array(),
      ),
    ),
  );
}

/**
 * Implements hook_field_widget_settings_form().
 */
function partial_date_field_widget_settings_form($field, $instance) {
  module_load_include('admin.inc', 'partial_date');
  return _partial_date_field_widget_settings_form($field, $instance);
}

/**
 * Implements hook_field_widget_form().
 */
function partial_date_field_widget_form(&$form, &$form_state, $field, $instance, $langcode, $items, $delta, $base) {
  module_load_include('admin.inc', 'partial_date');
  return _partial_date_field_widget_form($form, $form_state, $field, $instance, $langcode, $items, $delta, $base);
}

/**
 * Implements hook_field_widget_error().
 *
 * @see partial_date_field_validate().
 */
function partial_date_field_widget_error($element, $error, $form, &$form_state) {
  switch ($error['error']) {
    case 'partial_date_incomplete_from':
    case 'partial_date_incomplete_to':
      $base_key = strpos($error['error'], 'from') ? 'from' : 'to';
      if (isset($error['partial_date_component']) && isset($element[$base_key][$error['partial_date_component']])) {
        form_error($element[$base_key][$error['partial_date_component']], $error['message']);
      }
      else {
        form_error($element[$base_key], $error['message']);
      }
      break;

    case 'partial_date_incomplete_txt_short':
    case 'partial_date_incomplete_txt_long':
      $base_key = strpos($error['error'], 'from') ? 'from' : 'to';
      form_error($element['year_to'], $error['message']);
      break;

    default:
      form_error($element['from'], $error['message']);
      break;
  }
}

/**
 * Helper function to assign the correct components into an array that the
 * formatters can use.
 */
function partial_date_field_widget_reduce_date_components($item, $is_start = TRUE, $is_approx = FALSE) {
  if (empty($item)) {
    return FALSE;
  }
  $components = array();
  foreach (partial_date_components() as $key => $title) {
    if (!empty($item[$key . '_estimate'])) {
      list($start, $end) = explode('|', $item[$key . '_estimate']);
      $components[$key] = $is_start ? $start : $end;
      $components[$key . '_estimate'] = $item[$key . '_estimate'];
      // We hit this on save, so we can not rely on the load set.
      if (isset($item[$key . '_estimate_label'])) {
        $components[$key . '_estimate_label'] = $item[$key . '_estimate_label'];
        $components[$key . '_estimate_value'] = $item[$key . '_estimate_value'];
      }
      if (isset($item[$key . '_estimate_value'])) {
        $components[$key . '_estimate_value'] = $item[$key . '_estimate_value'];
      }
    }
    else {
      $components[$key] = isset($item[$key]) && strlen($item[$key]) ? $item[$key] : NULL;;
    }
  }
  // No easy way to test a 0 value :{
  $has_data = FALSE;
  foreach ($components as $key => $value) {
    if (strlen($value)) {
      $has_data = TRUE;
      break;
    }
  }
  if (!$has_data) {
    return FALSE;
  }
  return $components;
}

################################################################################
#  ------------------------------------                                        #
#  Field API Hooks & Helpers: Formatter                                        #
#  ------------------------------------                                        #
#                                                                              #
#  Implements:                                                                 #
#   * hook_field_formatter_info()                                              #
#   * hook_field_formatter_settings_form()                                     #
#   * hook_field_formatter_settings_summary()                                  #
#   * hook_field_formatter_view()                                              #
#                                                                              #
#  Helpers:                                                                    #
#   * partial_date_format_default_options()                                    #
#     Default formatter options for the supported format types.                #
#                                                                              #
#   * partial_date_format_types()                                              #
#     The core format types implemented by the module. Since we are not with   #
#     complete dates, we can not fallback on the standard PHP formatters.      #
#                                                                              #
#   * partial_date_generate_date()                                             #
#     Generates an example date item for deminstration of format only.         #
#     This may not represent the parameters that are passed in.                #
#                                                                              #
#   * partial_date_txt_override_options()                                      #
#     Formatter options on how to use the date descriptions.                   #
#                                                                              #
#   * partial_date_estimate_handling_options()                                 #
#     Formatter options on how to display the estimate values.                 #
#                                                                              #
################################################################################

/**
 * Implements hook_field_formatter_info().
 */
function partial_date_field_formatter_info() {
  module_load_include('admin.inc', 'partial_date');
  return _partial_date_field_formatter_info();
}

/**
 * Implements hook_field_formatter_settings_form().
 */
function partial_date_field_formatter_settings_form($field, $instance, $view_mode, $form, &$form_state) {
  module_load_include('pages.inc', 'partial_date');
  return _partial_date_field_formatter_settings_form($field, $instance, $view_mode, $form, $form_state);
}

/**
 * Implements hook_field_formatter_settings_summary().
 */
function partial_date_field_formatter_settings_summary($field, $instance, $view_mode) {
  module_load_include('admin.inc', 'partial_date');
  return _partial_date_field_formatter_settings_summary($field, $instance, $view_mode);
}

/**
 * Implements hook_field_formatter_view().
 *
 * This handles any text override options before passing the values onto the
 * partial_date_render() or partial_date_render_range().
 */
function partial_date_field_formatter_view($object_type, $object, $field, $instance, $langcode, $items, $display) {
  $has_range = strpos($field['type'], 'range');
  $widget_settings = $instance['widget']['settings'];

  $element = array();
  foreach ($items as $delta => $item) {
    $override = FALSE;
    if (!is_array($item)) {
      continue;
    }
    $item += array(
      'txt_short' => NULL,
      'txt_long' => NULL,
      'check_approximate' => 0,
    );
    switch ($display['settings']['use_override']) {
      case 'short':
        if (strlen($item['txt_short'])) {
          $override = $item['txt_short'];
        }
        break;
      case 'long':
        if (strlen($item['txt_long'])) {
          $override = $item['txt_long'];
        }
        break;

      case 'long_short':
        if (strlen($item['txt_long'])) {
          $override = $item['txt_long'];
        }
        elseif (strlen($item['txt_short'])) {
          $override = $item['txt_short'];
        }

      case 'short_long':
        if (strlen($item['txt_short'])) {
          $override = $item['txt_short'];
        }
        elseif (strlen($item['txt_long'])) {
          $override = $item['txt_long'];
        }
        break;
    }

    if ($override !== FALSE) {
      $element[$delta] = array('#markup' => check_plain($override));
    }
    else {
      $to = $from = FALSE;
      // The additonal "Approximate only" checkbox.
      $display['settings']['is_approximate'] = FALSE;
      if (!empty($widget_settings['theme_overrides']['check_approximate'])) {
        $display['settings']['is_approximate']  = !empty($item['check_approximate']);
      }
      if (isset($item['from'])) {
        $from = partial_date_field_widget_reduce_date_components($item['from'], TRUE);
      }
      if (isset($item['to'])) {
        $to = partial_date_field_widget_reduce_date_components($item['to'], FALSE);
      }

      $markup = '';
      if ($to && $from) {
        $markup = partial_date_render_range($from, $to, $display['settings']);
      }
      elseif ($to xor $from) {
        $markup = partial_date_render($from ? $from : $to, $display['settings']);
      }
      unset($display['settings']['is_approximate']);
      if ($markup) {
        $element[$delta] = array('#markup' => $markup);
      }
    }
  }

  return $element;
}

function partial_date_render_range($from = NULL, $to = NULL, $settings = array()) {
  if (empty($from) && empty($to)) {
    return '';
  }
  // TODO: Make this configurable.
  $settings += array(
    'reduce' => TRUE,
    'format' => 'short',
  );
  $settings['component_settings'] += partial_date_format_settings($settings['format']);
  if ($settings['reduce']) {
    partial_date_reduce_range_values($from, $to);
  }

  $from = partial_date_render($from, $settings);
  $to = partial_date_render($to, $settings);

  if ($to && $from) {
    return theme('partial_date_range', array('from' => $from, 'to' => $to, 'settings' => $settings));
  }
  // One or both will be empty.
  return $from . $to;
}

function partial_date_render($item, $settings = array()) {
  if (empty($item)) {
    return '';
  }
  $settings += array(
    'format' => 'short',
    'component_settings' => array(),
    'is_approximate' => 0,
  );
  if ($settings['format'] != 'custom') {
    $settings['component_settings'] = partial_date_format_settings($settings['format']);
  }

  return theme('partial_date', array(
    'item' => $item,
    'settings' => $settings['component_settings'],
    'format' => $settings['format'],
    'is_approximate' => $settings['is_approximate'],
  ));
}

function partial_date_format_types($add_custom = FALSE) {
  $formats = &drupal_static(__FUNCTION__);
  if (!$formats) {
    $formats = variable_get('partial_date_format_types', array(
      'short' => t('Short', array(), array('context' => 'datetime')),
      'medium' => t('Medium', array(), array('context' => 'datetime')),
      'long' => t('Long', array(), array('context' => 'datetime')),
    ));
    $formats['custom'] = t('Custom', array(), array('context' => 'datetime'));
  }
  if (!$add_custom) {
    $clone = $formats;
    unset($formats['custom']);
    return $clone;
  }
  return $formats;
}

function partial_date_format_settings($type) {
  $settings = &drupal_static(__FUNCTION__, array());
  if (!isset($settings[$type])) {
    $settings[$type] = variable_get('partial_date_format_' . $type, partial_date_format_default_options($type));
  }
  return $settings[$type];
}

/**
 * Provides the default settiings for the partial date formats.
 */
function partial_date_format_default_options($format) {
  $formats = array(
    'short' => array(
      'display' => array(
        'year' => 'estimate_label',
        'month' => 'estimate_label',
        'day' => 'estimate_label',
        'hour' => 'estimate_label',
        'minute' => 'estimate_label',
        'second' => 'none',
        'timezone' => 'none',
      ),
      'components' => array(
        'approx' => array('value' => '', 'weight' => -1),
        'year' => array('format' => 'y-ce', 'weight' => 0, 'empty' => ''),
        'month' => array('format' => 'm', 'weight' => 1, 'empty' => ''),
        'day' => array('format' => 'j', 'weight' => 2, 'empty' => ''),
        'hour' => array('format' => 'H', 'weight' => 3, 'empty' => ''),
        'minute' => array('format' => 'i', 'weight' => 4, 'empty' => ''),
        'second' => array('format' => 's', 'weight' => 5, 'empty' => ''),
        'timezone' => array('format' => 'T', 'weight' => 6, 'empty' => ''),
        'c1' => array('value' => '', 'weight' => 7),
        'c2' => array('value' => '', 'weight' => 8),
        'c3' => array('value' => '', 'weight' => 9),
      ),
      'separator' => array(
        'date' => '/',
        'time' => ':',
        'datetime' => ' ',
        'other' => ' ',
        'range' => '',
      ),
      'meridiem' => 'a',
      'year_designation' => 'ce',
    ),
    'medium' => array(
      'display' => array(
        'year' => 'estimate_label',
        'month' => 'estimate_label',
        'day' => 'estimate_label',
        'hour' => 'estimate_label',
        'minute' => 'estimate_label',
        'second' => 'estimate_label',
        'timezone' => 'date_only',
      ),
      'components' => array(
        'approx' => array('value' => '', 'weight' => -1),
        'year' => array('format' => 'Y-ce', 'weight' => 0, 'empty' => ''),
        'month' => array('format' => 'M', 'weight' => 1, 'empty' => ''),
        'day' => array('format' => 'j-S', 'weight' => 2, 'empty' => ''),
        'hour' => array('format' => 'h', 'weight' => 3, 'empty' => ''),
        'minute' => array('format' => 'i', 'weight' => 4, 'empty' => ''),
        'second' => array('format' => 's', 'weight' => 5, 'empty' => ''),
        'timezone' => array('format' => 'T', 'weight' => 6, 'empty' => ''),
        'c1' => array('value' => '', 'weight' => 7),
        'c2' => array('value' => '', 'weight' => 8),
        'c3' => array('value' => '', 'weight' => 9),
      ),
      'separator' => array(
        'date' => ' ',
        'time' => ':',
        'datetime' => ' ',
        'other' => ' ',
        'range' => '',
      ),
      'meridiem' => 'a',
      'year_designation' => 'ce',
    ),
    'long' => array(
      'display' => array(
        'year' => 'estimate_label',
        'month' => 'estimate_label',
        'day' => 'estimate_label',
        'hour' => 'estimate_label',
        'minute' => 'estimate_label',
        'second' => 'estimate_label',
        'timezone' => 'date_only',
      ),
      'components' => array(
        'approx' => array('value' => '', 'weight' => -1),
        'year' => array('format' => 'Y-ce', 'weight' => 0, 'empty' => ''),
        'month' => array('format' => 'F', 'weight' => 1, 'empty' => ''),
        'day' => array('format' => 'j-S', 'weight' => 2, 'empty' => ''),
        'hour' => array('format' => 'h', 'weight' => 3, 'empty' => ''),
        'minute' => array('format' => 'i', 'weight' => 4, 'empty' => ''),
        'second' => array('format' => 's', 'weight' => 5, 'empty' => ''),
        'timezone' => array('format' => 'e', 'weight' => 6, 'empty' => ''),
        'c1' => array('value' => '', 'weight' => 7),
        'c2' => array('value' => '', 'weight' => 8),
        'c3' => array('value' => '', 'weight' => 9),
      ),
      'separator' => array(
        'date' => ' ',
        'time' => ':',
        'datetime' => ', ',
        'other' => ' ',
        'range' => '',
      ),
      'meridiem' => 'a',
      'year_designation' => 'ce',
    ),
  );

  if (isset($formats[$format])) {
    return $formats[$format];
  }
  return $formats['short'];
}

function partial_date_txt_override_options() {
  return array(
    'none' => t('Use date only', array(), array('context' => 'datetime')),
    'short' => t('Use short description', array(), array('context' => 'datetime')),
    'long' => t('Use long description', array(), array('context' => 'datetime')),
    'long_short' => t('Use long or short description', array(), array('context' => 'datetime')),
    'short_long' => t('Use short or long description', array(), array('context' => 'datetime')),
  );
}

################################################################################
#  --------------------------                                                  #
#  Theming related functions:                                                  #
#  --------------------------                                                  #
#                                                                              #
#  Implements:                                                                 #
#   * hook_theme()                                                             #
#                                                                              #
#  Theming functions:                                                          #
#   * theme_partial_date()                                                     #
#   * theme_partial_date_long_date_format()                                    #
#   * theme_partial_date_medium_date_format()                                  #
#   * theme_partial_date_short_date_format()                                   #
#                                                                              #
#  Helpers:                                                                    #
#   * partial_date_reduce_range_values()                                       #
#     Reduces the from date component array so that individual components that #
#     are common to both are not repeated.                                     #
#                                                                              #
################################################################################

/**
 * Implements hook_theme().
 */
function partial_date_theme() {
  return array(
    'partial_date_element' => array(
      'render element' => 'element',
    ),
    'partial_date_range_inline_element' => array(
      'render element' => 'element',
      'file' => 'partial_date.theme.inc',
    ),
    'partial_date' => array(
      'variables' => array('item' => NULL, 'format' => 'short', 'settings' => array()),
    ),
    'partial_date_range' => array(
      'variables' => array('from' => NULL, 'to' => NULL, 'settings' => array()),
    ),
    'partial_date_format_settings_form' => array(
      'render element' => 'form',
      'file' => 'partial_date.pages.inc',
    ),
    'partial_date_inline_form_element' => array(
      'render element' => 'element',
      'file' => 'partial_date.theme.inc',
    ),
  );
}


/**
 * The theme wrapper for a single date component.
 * todo: floating support.
 */
function theme_partial_date_element($variables) {
  $element = $variables['element'];
  return '<div class="partial-date-element clearfix">' . drupal_render_children($element) . '</div>';
}

function theme_partial_date_range($variables) {
  $to = $variables['to'];
  $from = $variables['from'];
  $settings = $variables['settings'];
  $separator = '';
  if (!empty($settings['component_settings'])
    && !empty($settings['component_settings']['separator'])
    && !empty($settings['component_settings']['separator']['range'])) {
    $separator = $settings['component_settings']['separator']['range'];
  }
  if (!strlen($separator)) {
    $separator = t(' to ', array(), array('context' => 'datetime'));
  }
  return t('@from@separator@to', array('@from' => $from, '@to' => $to, '@separator' => $separator));
}

/**
 * TODO
 *
 * Template preprocess function to add theme suggestions for the various
 * partial date format types.
 */

/**
 * The partial date theme callback.
 *
 * Allows easy override of the format if required.
 */
function theme_partial_date($variables) {
  $item = $variables['item'];
  $settings = $variables['settings'];
  $settings['format'] = $variables['format'];
  $settings['is_approximate'] = !empty($variables['is_approximate']);
  return partial_date_format($item, $settings);
}

function partial_date_reduce_range_values(&$from, &$to) {
  // Reduce dates on granularity values.
  foreach (array_keys(partial_date_components()) as $key) {
    // Excat match as we need to compare '' to 0.
    if (!isset($from[$key]) && !isset($to[$key])) {
      continue;
    }
    elseif ((isset($from[$key]) || !isset($to[$key])) || $from[$key] !== $to[$key]) {
      break;
    }
    $from[$key] = NULL;
  }
}

################################################################################
#  --------------------------                                                  #
#  Element Related Functions:                                                  #
#  --------------------------                                                  #
#                                                                              #
#  Implements:                                                                 #
#   * hook_element_info()                                                      #
#                                                                              #
#  Helpers:                                                                    #
#   * partial_date_element_validate()                                          #
#     Element #element_validate callback.                                      #
#                                                                              #
#   * partial_date_element_process()                                           #
#     Element #process callback.                                               #
#                                                                              #
################################################################################

/**
 * Implements hook_element_info().
 *
 * Provides a singular element that can handle all of the implemented partial
 * date components; datetime granularility and timezone components.
 */
function partial_date_element_info() {
  $types = array();
  $types['partial_datetime_element'] = array(
    '#input' => TRUE,
    '#element_validate' => array('partial_date_element_validate'),
    '#process' => array('partial_date_element_process'),
    '#theme' => 'partial_date_element',
    '#theme_wrappers' => array('form_element'),
  );
  return $types;
}

/**
 * TODO: Validates the date type to stop dates like February 30, 2006.
 */
function partial_date_element_validate($element, $form_state) {
  module_load_include('admin.inc', 'partial_date');
  _partial_date_element_validate($element);
}

/**
 * Roll out a single date element.
 */
function partial_date_element_process($element) {
  module_load_include('admin.inc', 'partial_date');
  return _partial_date_element_process($element);
}

################################################################################
#  ------------------                                                          #
#  Views Integration:                                                          #
#  ------------------                                                          #
################################################################################

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

################################################################################
#  ----------------------                                                      #
#  API related functions:                                                      #
#  ----------------------                                                      #
#                                                                              #
#  Note: It would be great to move these to the date_api.                      #
#                                                                              #
#  Main functions include:                                                     #
#   * partial_date_components()                                                #
#     Returns the date and time values used by the module.                     #
#     This controls almost everything, from defining the schema to controlling #
#     the output of the formatters.                                            #
#                                                                              #
#   * partial_date_day_ordinal_suffix()                                        #
#     Returns the translated English ordinal suffix for a given day.           #
#                                                                              #
#   * partial_date_granularity_field_options()                                 #
#     Returns select options for various components.                           #
#                                                                              #
#   * partial_date_is_leap_year()                                              #
#     Checks to see if the specified year is a leap year.                      #
#                                                                              #
#   * partial_date_mktime()                                                    #
#     Returns a timestamp (int / float) based on the available components.     #
#                                                                              #
#   * partial_date_month_abbreviations()                                       #
#     Returns an option list of month abbreviations.                           #
#                                                                              #
#   * partial_date_month_matrix()                                              #
#     Returns the valid month lengths based of the specified year.             #
#                                                                              #
#   * partial_date_timezone_handling_correlation()                             #
#     Forces a given timezone into the specified timezone handling option.     #
#                                                                              #
#   * partial_date_timezone_option_is_selectable()                             #
#     Determines if the timezone component should be rendered.                 #
#                                                                              #
#   * partial_date_timezone_handling_options()                                 #
#     Returns an option list of supported timezone handling options.           #
#                                                                              #
#   * partial_date_year_designation_decorator()                                #
#     Returns the year with the appropriative designation added.               #
#                                                                              #
#   * partial_date_year_designation_options()                                  #
#     Returns an option list of supported year designations.                   #
#                                                                              #
################################################################################

/**
 * The minimum year that the module supports.
 *
 * Modifying this will alter how new timestamps are stored in the database.
 *
 * Setting to the something huge like 999999999999 should be OK, which would
 * be needed for things like the scienific age of the universe. +/- 2000 years
 * do not calculate leap years etc, and use a fixed number of seconds per year
 * based on the length of the tropical year in 2000.
 *
 * @var int
 */
define('PD2_YEAR_MIN', -999999999999);

/**
 * The maximum year that the module supports.
 *
 * Modifying this will alter how new timestamps are stored in the database.
 *
 * @var int
 */
define('PD2_YEAR_MAX', 999999999999);

/**
 * The number of seconds for a tropical year in 2000.
 *
 * Outside of the 1AD to 3999AD, leap years are ignored and a set number of
 * seconds per year are used to calculate the number seconds per year for the
 * timestamp estimations. This is a float column, so the percision of this
 * should be calculated to decide if this can be reduced even more.
 *
 * @var int
 */
define('PD2_SEC_PER_YEAR', 31556925);

/**
 * These are the core components that always exist, but are shown or hidden
 * depending on the selected field settings.
 */
function partial_date_components(array $excluded_components = NULL) {
  static $components = NULL;
  if (!isset($components)) {
    $components = array(
      'year' => t('Year', array(), array('context' => 'datetime')),
      'month' => t('Month', array(), array('context' => 'datetime')),
      'day' => t('Day', array(), array('context' => 'datetime')),
      'hour' => t('Hour', array(), array('context' => 'datetime')),
      'minute' => t('Minute', array(), array('context' => 'datetime')),
      'second' => t('Second', array(), array('context' => 'datetime')),
      'timezone' => t('Timezone', array(), array('context' => 'datetime')),
    );
  }
  if ($excluded_components) {
    return array_diff_key($components, array_flip($excluded_components));
  }

  return $components;
}

/**
 * Returns a translated array of timezone handling options.
 *
 * Currently, this is a copy of the Dates module options.
 */
function partial_date_timezone_handling_options() {
  return array(
    'none' => t('No timezone conversion'),
    'date' => t('User selectable', array(), array('context' => 'datetime')),
    'site' => t("Site's timezone"),
    'user' => t("User's account timezone"),
    'utc' => t('UTC', array(), array('context' => 'datetime')),
  );
}

/**
 * Helper function to control how and if the timezone component should be
 * rendered.
 */
function partial_date_timezone_option_is_selectable($tz_handling) {
  return ($tz_handling == 'none' || $tz_handling == 'date');
}

/**
 * Helper function to determine the correct timezone based on the timezone
 * handling options used.
 *
 * @param string $timezone
 *   Current timezone from the database or widget.
 *
 * @param string $tz_handling
 *   The timezone handling options that needs enforcing.
 */
function partial_date_timezone_handling_correlation($timezone = '', $tz_handling = 'none') {
  global $user;

  // Override or return unchanged depending on the set action.
  switch ($tz_handling) {
    case 'utc':
      return 'UTC';

    case 'site':
      return variable_get('date_default_timezone', @date_default_timezone_get());

    case 'user':
      if (variable_get('configurable_timezones', 1) && !empty($user->timezone)) {
        return $user->timezone;
      }
      else {
        return variable_get('user_default_timezone', DRUPAL_USER_TIMEZONE_DEFAULT) ? '' : variable_get('date_default_timezone', '');
      }

    case 'date':
    case 'none':
      // Parse the existing timezone.
      $timezone = isset($timezone) ? $timezone : '';
      switch ($timezone) {
        case '--user--':
        case '--site--':
          $timezone = partial_date_timezone_handling_correlation($timezone, trim($timezone, '-'));
          break;

      }
      return $timezone;

    default:
      return '';

  }
}

/**
 * Returns option lists for the various components, with the exception of year
 * which is not supported.
 *
 * @param string $type
 *   One of the date granularity keys: year, month, day, etc.
 * @param array $options
 *   Additional values to prefix onto the options list.
 */
function partial_date_granularity_field_options($type, $options = array(), $increment = 1) {
  switch ($type) {
    case 'second':
    case 'minute':
      return $options + date_minutes('i', FALSE, $increment);

    case 'hour':
      return $options + drupal_map_assoc(range(0, 23));

    case 'day':
      return $options + drupal_map_assoc(range(1, 31));

    case 'month':
      return $options + drupal_map_assoc(range(1, 12), 'map_month');

    case 'timezone':
      // Ref: Date API module
      return $options + date_timezone_names(TRUE);

    case 'year':
    default:
      return $options;
  }
}

/**
 * Maps out the valid month ranges for a given year.
 *
 * @param int $year
 * @return array
 *   Note, there is no array index.
 */
function partial_date_month_matrix($year = NULL) {
  if ($year && partial_date_is_leap_year($year)) {
    return array(31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
  }
  return array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
}

/**
 * Returns a translated array of short month names.
 */
function partial_date_month_abbreviations($month) {
  static $month_names;
  if (empty($month_names)) {
    $month_names = array(
      1 => 'Jan', 2 => 'Feb', 3 => 'Mar', 4 => 'Apr', 5 => 'May', 6 => 'Jun',
      7 => 'Jul', 8 => 'Aug', 9 => 'Sep', 10 => 'Oct', 11 => 'Nov', 12 => 'Dec');
    foreach ($month_names as $key => $month_name) {
      $month_names[$key] = t($month_name, array(), array('context' => 'datetime'));
    }
  }
  if ($month) {
    return $month_names[$month];
  }
  return $month_names;
}

/**
 * Returns a translated array of month names.
 */
function partial_date_month_names($month) {
  static $month_names;
  if (empty($month_names)) {
    $month_names = array(
      1 => 'January', 2 => 'February', 3 => 'March', 4 => 'April', 5 => 'May',
      6 => 'June', 7 => 'July', 8 => 'August', 9 => 'September',
      10 => 'October', 11 => 'November', 12 => 'December');

    foreach ($month_names as $key => $month_name) {
      $month_names[$key] = t($month_name, array(), array('context' => 'datetime'));
    }
  }
  if ($month) {
    return $month_names[$month];
  }
  return $month_names;
}

/**
 * Returns a translated array of weekday names.
 */
function partial_date_weekday_name_abbreviations($week_day_number, $length = 3) {
  $name = partial_date_weekday_names($week_day_number);
  if (drupal_strlen($name) > $length) {
    return drupal_substr($name, 0, $length);
  }
  return $name;
}

/**
 * Returns a translated array of weekday names.
 */
function partial_date_weekday_names($week_day_number) {
  static $day_names;
  if (empty($day_names)) {
    $day_names = array(
      0 => 'Sunday', 1 => 'Monday', 2 => 'Tuesday', 3 => 'Wednesday',
      4 => 'Thursday', 5 => 'Friday', 6 => 'Saturday');

    foreach ($day_names as $key => $day_name) {
      $day_names[$key] = t($day_name, array(), array('context' => 'datetime'));
    }
  }
  if ($week_day_number) {
    return $day_names[$week_day_number];
  }
  return $day_names;
}

/**
 * Decorates a year with the given year designations.
 *
 * As there is no year 0, so an empty year will return an empty string.
 */
function partial_date_year_designation_decorator($year, $designation = 'ce') {
  static $designation_suffixes;
  if (empty($designation_suffixes)) {
    $designation_suffixes = array(
      'BC' => 'BC',
      'AD' => 'AD',
      'BCE' => 'BCE',
      'CE' => 'CE',
    );
    foreach ($designation_suffixes as $key => $designation_suffix) {
      $designation_suffixes[$key] = t($designation_suffix, array(), array('context' => 'datetime'));
    }
  }

  if (empty($year) || !is_numeric($year)) {
    return '';
  }
  switch ($designation) {
    case 'ce':
      return $year > 0 ? $designation_suffixes['CE'] : $designation_suffixes['BCE'];

    case 'bce':
      return $year > 0 ? '' : $designation_suffixes['BCE'];

    case 'ad':
      return $year > 0 ? $designation_suffixes['AD'] : $designation_suffixes['BC'];

    case 'bc':
      return $year > 0 ? '' : $designation_suffixes['BC'];

    case 'sign':
    default:
      return '';
  }
}

/**
 * Returns a translated ordinal suffix for a given day of the month.
 */
function partial_date_day_ordinal_suffix($day) {
  if (empty($day)) {
    return '';
  }
  static $suffixes;
  if (empty($suffixes)) {
    $suffixes = array(
      'st' => 'st',
      'nd' => 'nd',
      'rd' => 'rd',
      'th' => 'th',
    );
    foreach ($suffixes as $key => $suffix) {
      $suffixes[$key] = t($suffix, array(), array('context' => 'datetime'));
    }
  }

  switch (($day = abs($day)) % 100) {
    case 11:
    case 12:
    case 13:
      return $suffixes['th'];

    default:
      switch ($day % 10) {
        case 1:
          return $suffixes['st'];

        case 2:
          return $suffixes['nd'];

        case 3:
          return $suffixes['rd'];

        default:
          return $suffixes['th'];
      }
  }
}

/**
 * Returns true, if given $year is a leap year.
 *
 * @param  integer $year
 * @return boolean true, if year is leap year
 */
function partial_date_is_leap_year($year) {
  if (empty($year)) {
    return FALSE;
  }

   if ($year < 1582) {
    // pre Gregorio XIII - 1582
    return $year % 4 == 0;
   }
   else {
     // post Gregorio XIII - 1582
     return (($year % 4 == 0) && ($year % 100 != 0)) || ($year % 400 == 0);
   }
}

/**
 * Generates a numeric date string.
 */
function partial_date_float(array $c) {
  foreach (partial_date_components(array('timezone')) as $key => $label) {
    if (!isset($c[$key]) || !strlen($c[$key])) {
      $c[$key] = 0;
    }
    elseif ($key != 'year' && $key != 'month') {
      // Increment hours, minutes and seconds to allow the module to distintish
      // between 0 meaning unset and 1 to 24/60 being the actual values.
      // Day is incremented to provide a buffer to add / remove the timezone.
      $c[$key] = $c[$key] + 1;
    }
  }

  $date = abs($c['year'])
      . sprintf('%02s', $c['month'])  // 0 or 1-12
      . sprintf('%02s', $c['day']) // 0 or 2-32
      . sprintf('%02s', $c['hour']) // 0 or 1-24
      . sprintf('%02s', $c['minute']) // 0 or 1-60
      . sprintf('%02s', $c['second']); // 0 or 1-60
  return ((float) ltrim($date, '0')) * ($c['year'] >= 0 ? 1.0 : -1.0);
}

/**
 * Creates a timestamp based on the available components.
 *
 * Copied from Zend_Date. Significantly modified.
 *
 * @param array $components
 *   An array of all the defined date components including timezone.
 *
 * @return  integer|float
 *   An approx. timestamp (number of seconds elapsed relative to 1970/01/01 00:00:00 GMT/UTC)
 */
function partial_date_mktime(array $components) {
  $components = array_intersect_key($components, partial_date_components());
  extract($components, EXTR_SKIP);

  if ((1901 < $year) and ($year < 2038)) {
    $oldzone = @date_default_timezone_get();
    if ($timezone && ($timezone != $oldzone)) {
      date_default_timezone_set($timezone);
    }
    $result = @mktime($hour, $minute, $second, $month, $day, $year);
    if ($timezone && ($timezone != $oldzone)) {
      date_default_timezone_set($oldzone);
    }
    if ($result !== FALSE) {
      return $result;
    }
  }

        // Get approx. offset
# Error in float pre 1900 probably makes this pointless
#        if ($gmt !== true) {
#          $tz = new DateTimeZone($timezone);
#          $second += $tz->getOffset(date_create('2000-01-01 00:00 GMT'));
#        }

  // date to integer
  $day   = intval($day);
  $month = intval($month);
  $year  = intval($year);
  $_monthTable = partial_date_month_matrix();

  if ($month > 12) {
    $overlap = floor($month / 12);
    $year   += $overlap;
    $month  -= $overlap * 12;
  }
  else {
    $overlap = ceil((1 - $month) / 12);
    $year   -= $overlap;
    $month  += $overlap * 12;
  }

  $date = 0;
  // correct months > 12 and months < 1
  if ($year < -99999 || $year > 99999) {
    // Calculate the average number of seconds in a year.
    $seconds_in_year = ($year - 1970) * PD2_SEC_PER_YEAR;

    $leapyear = partial_date_is_leap_year($year);
    for ($mcount = 0; $mcount < ($month - 1); $mcount++) {
      $date += $_monthTable[$mcount];
      if (($leapyear === true) and ($mcount == 1)) {
          $date++;
      }
    }
    $date += $day - 1;
    $date = (($date * 86400) + ($hour * 3600) + ($minute * 60) + $second + $seconds_in_year);
  }
  elseif ($year >= 1970) {
    // Date is after UNIX epoch
    // go through leapyears
    // add months from latest given year
    for ($count = 1970; $count <= $year; $count++) {
      $leapyear = partial_date_is_leap_year($count);
      if ($count < $year) {
        $date += 365;
        if ($leapyear === true) {
            $date++;
        }
      }
      else {
        for ($mcount = 0; $mcount < ($month - 1); $mcount++) {
          $date += $_monthTable[$mcount];
          if (($leapyear === true) and ($mcount == 1)) {
              $date++;
          }
        }
      }
    }

    $date += $day - 1;
    $date = (($date * 86400) + ($hour * 3600) + ($minute * 60) + $second);
  }
  else {
    // Date is before UNIX epoch
    // go through leapyears
    // add months from latest given year
    for ($count = 1969; $count >= $year; $count--) {
      $leapyear = partial_date_is_leap_year($count);
      if ($count > $year) {
        $date += 365;
        if ($leapyear === true) {
          $date++;
        }
      }
      else {
        for ($mcount = 11; $mcount > ($month - 1); $mcount--) {
          $date += $_monthTable[$mcount];
          if (($leapyear === true) and ($mcount == 2)) {
            $date++;
          }
        }
      }
    }

    $date += ($_monthTable[$month - 1] - $day);
    $date = -(($date * 86400) + (86400 - (($hour * 3600) + ($minute * 60) + $second)));

    // gregorian correction for 5.Oct.1582
    if ($date < -12220185600) {
        $date += 864000;
    }
    elseif ($date < -12219321600) {
        $date  = -12219321600;
    }
  }
  return $date;
}


/**
 * Function used by uasort to sort structured arrays by weight.
 */
function partial_date_sort($a, $b) {
  $a_weight = (is_array($a) && isset($a['weight'])) ? $a['weight'] : 0;
  $b_weight = (is_array($b) && isset($b['weight'])) ? $b['weight'] : 0;
  if ($a_weight == $b_weight) {
    return 0;
  }
  return ($a_weight < $b_weight) ? -1 : 1;
}

/**
 * Returns any configured separators for two components.
 */
function _partial_date_component_separator($a, $b, $separators = array()) {
  if ($a === FALSE) {
    return;
  }
  $a_type = _partial_date_component_type($a);
  $b_type = _partial_date_component_type($b);
  if (!$a_type || !$b_type) {
    $key = 'other';
  }
  elseif ($a_type == $b_type) {
    $key = $a_type;
  }
  else {
    $key = 'datetime';
  }
  return isset($separators[$key]) ? $separators[$key] : FALSE;

}
/**
 * Helper function to determine the component type for inserting the component
 * separator.
 *
 * @return mixed
 *   One of date, time or FALSE.
 */
function _partial_date_component_type($key) {
  switch ($key) {
    case 'year':
    case 'month':
    case 'day':
      return 'date';

    case 'hour':
    case 'minute':
    case 'second':
      return 'time';

    case 'timezone':
    default:
      return FALSE;
  }
}


function _partial_date_render_component($key, $item, $field, $format) {
  switch ($field) {
    case 'none':
      return '';

    case 'date_only':
      return isset($item[$key]) ? $item[$key] : '';

    case 'estimate_label':
    case 'estimate_range': // Start (single or from dates) or End (to dates) of estimate range
    case 'estimate_component': // Date component with fallback to estimate component
    case 'date_or':

    default:
      return $field;
  }
}

function partial_date_format($item, array $settings = array()) {
  $components = array();
  uasort($settings['components'], 'partial_date_sort');
  // Skip unless we have a 12 hour format, then enforce it.
  if (isset($settings['components']['hour'])
      && ($settings['components']['hour'] == 'h' || $settings['components']['hour'] == 'g')) {
    if (empty($settings['meridiem'])) {
      $settings['meridiem'] = 'a';
    }
  }
  else {
    $settings['meridiem'] = '';
  }

  // Hide year designation if no valid year.
  if (empty($item['year'])) {
    $settings['year_designation'] = '';
  }
  elseif (!isset($settings['year_designation'])) {
    $settings['year_designation'] = 'ce';
  }

  if (empty($settings['is_approximate']) || !isset($settings['is_approximate'])) {
    $settings['components']['approx'] = '';
  }

  $valid_components = partial_date_components();
  $last_type = FALSE;
  foreach ($settings['components'] as $type => $component) {
    if (isset($valid_components[$type])) {
      $markup = '';
      // Value is determined by the $settings['display]
      // If estimate, use this other use value
      $display_type = empty($settings['display'][$type]) ? 'estimate_label' : $settings['display'][$type];
      $estimate = empty($item[$type . '_estimate']) ? FALSE : $item[$type . '_estimate'];
      $value = isset($item[$type]) && strlen($item[$type]) ? $item[$type] : FALSE;
      // If no estimate, switch to the date only formating option.
      if (!$estimate && ($display_type == 'date_or' || strpos($display_type, 'estimate_') === 0)) {
        $display_type = 'date_only';
      }

      switch ($display_type) {
        case 'none':
          // We need to avoid adding an empty option.
          continue;

        case 'date_only':
          if ($value !== FALSE) {
            $markup = partial_date_format_component($value, $component['format'], $item, $settings);
          }
          break;

        case 'date_or':
          if ($value !== FALSE) {
            $markup = partial_date_format_component($value, $component['format'], $item, $settings);
            break;
          }
          // Fall through

        case 'estimate_label':
          $markup = $item[$type . '_estimate_label'];
          // We no longer have a date / time like value.
          $type = 'other';
          break;

        case 'estimate_range':
          list($start, $end) = explode('|', $item[$type . '_estimate']);
          $start = partial_date_format_component($start, $component['format'], $item, $settings);
          $end = partial_date_format_component($end, $component['format'], $item, $settings);
          if (strlen($start) && strlen($end)) {
            $markup = t('@estimate_start to @estimate_end', array('@estimate_start' => $start, '@estimate_end' => $end));
          }
          elseif (strlen($start) xor strlen($end)) {
            $markup = strlen($start) ? $start : $end;
          }
          break;

        case 'estimate_component':
          $markup = partial_date_format_component($item[$type . '_estimate_value'], $component['format'], $item, $settings);
          break;

      }

      if (!strlen($markup)) {
        if (isset($component['empty']) && strlen($component['empty'])) {
          // What do we get? If numeric, assume a date / time component, otherwise
          // we can assume that we no longer have a date / time like value.
          $markup = $component['empty'];
          if (!is_numeric($markup)) {
            $type = 'other';
          }
        }
      }
      if (strlen($markup)) {
        if ($separator = _partial_date_component_separator($last_type, $type, $settings['separator'])) {
          $components[] = $separator;
        }
        $components[] = $markup;
        $last_type = $type;
      }
    }
    elseif (isset($component['value']) && strlen($component['value'])) {
      if ($separator = _partial_date_component_separator($last_type, $type, $settings['separator'])) {
        $components[] = $separator;
      }
      $components[] = $component['value'];
      $last_type = $type;
    }

  }
  return implode('', $components);
}

function partial_date_format_component($value, $format, &$date, $additional = array()) {

  $additional += array(
    'year_designation' => 'ce',
  );
  // If dealing with 12 hour times, recalculate the value.
  if ($format == 'h' || $format == 'g') {
    if ($value > 12) {
      $value -= 12;
    }
    elseif ($value == 0) {
      $value = '12';
    }
    if (empty($additional['meridiem'])) {
      $additional['meridiem'] = 'a';
    }
  }
  else {
    $additional['meridiem'] = '';
  }

  // Add suffixes for year and time formats
  $suffix = '';
  switch ($format) {
    case 'd-S':
    case 'j-S':
      $suffix = partial_date_day_ordinal_suffix($value);
      break;

    case 'y-ce':
    case 'Y-ce':
      $suffix = partial_date_year_designation_decorator($value, $additional['year_designation']);
      if (!empty($suffix) && !empty($value)) {
        $value = abs($value);
      }
      break;
  }

  switch ($format) {
    case 'y-ce':
    case 'y':
      return (strlen($value) > 2 ?  substr($value, - 2) : $value) . $suffix;

    case 'F':
      return partial_date_month_names($value) . $suffix;

    case 'M':
      return partial_date_month_abbreviations($value) . $suffix;

    // Numeric representation of the day of the week  0 (for Sunday) through 6 (for Saturday)
    case 'w':
      if (!empty($date['year']) && !empty($date['month'])) {
        return partial_date_day_of_week($date['year'], $date['month'], $value) . $suffix;
      }
      return '';

    // A full textual representation of the day of the week.
    case 'l':
    // A textual representation of a day, three letters.
    case 'D':
      if (!empty($date['year']) && !empty($date['month'])) {
        $day = partial_date_day_of_week($date['year'], $date['month'], $value);
        if ($format == 'D') {
          return partial_date_weekday_name_abbreviations($day, 3) . $suffix;
        }
        else {
          return partial_date_weekday_names($day) . $suffix;
        }
      }
      return '';

    case 'n':
    case 'j':
    case 'j-S':
    case 'g':
    case 'G':
      return intval($value) . $suffix;

    case 'd-S':
    case 'd':
    case 'h':
    case 'H':
    case 'i':
    case 's':
    case 'm':
      return sprintf('%02s', $value) . $suffix;

    case 'Y-ce':
    case 'Y':
    case 'e':
      return $value . $suffix;

    case 'T':
      try {
        $tz = new DateTimeZone($value);
        $transitions = $tz->getTransitions();
        return $transitions[0]['abbr']  . $suffix;
      }
      catch (Exception $e) {}
      return '';


    // Todo: implement
    // Year types
    // ISO-8601 year number
    case 'o':

    // Day types
    // The day of the year
    case 'z':
    // ISO-8601 numeric representation of the day of the week
    case 'N':

    // Timezone offsets
    // Whether or not the date is in daylight saving time
    case 'I':
    // Difference to Greenwich time (GMT) in hours
    case 'O':
    // Difference to Greenwich time (GMT) with colon between hours and minutes
    case 'P':
    // Timezone offset in seconds
    case 'Z':

    default:
      return '';
  }
}

/**
 * Gets day of week, 0 = Sunday through 6 = Saturday.
 *
 * Pope Gregory removed 10 days - October 5 to October 14 - from the year 1582
 * and proclaimed that from that time onwards 3 days would be dropped from the
 * calendar every 400 years.
 *
 * Thursday, October 4, 1582 (Julian) was followed immediately by Friday,
 * October 15, 1582 (Gregorian).
 *
 * @see PEAR::Date_Calc
 */
function partial_date_day_of_week($year, $month, $day) {
  $greg_correction = 0;
  if ($year < 1582 || ($year == 1582 && ($month < 10 || ($month == 10 && $day < 15)))) {
    $greg_correction = 3;
  }

  if ($month > 2) {
    $month -= 2;
  }
  else {
    $month += 10;
    $year--;
  }

  $day = floor((13 * $month - 1) / 5) +
         $day + ($year % 100) +
         floor(($year % 100) / 4) +
         floor(($year / 100) / 4) - 2 *
         floor($year / 100) + 77 + $greg_correction;

  return $day - 7 * floor($day / 7);
}