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<?php

/**

 * @file

 * This module will make the date API available to other modules.

 * Designed to provide a light but flexible assortment of functions

 * and constants, with more functionality in additional files that

 * are not loaded unless other modules specifically include them.

 */

use Drupal\Core\Datetime\DrupalDateTime;

/**

 * Format options array.

 *

 * TODO Remove any formats not supported by the widget, if any.

 */

function date_datepicker_formats() {

  $formats = str_replace('i', 'i:s', array_keys(system_get_date_formats('short')));

  $formats = drupal_map_assoc($formats);

  return $formats;

}

function date_get_format($instance, $part = 'all') {

  switch ($instance['widget']['type']) {

    case 'date_select':

      $date_format = $instance['widget']['date_date_format'];

      $time_format = '';

      break;

    case 'date_popup':

      $date_format = datetime_get_format('date', $instance['widget']['date_date_format']);

      $time_format = datetime_get_format('date', $instance['widget']['date_time_format']);

      break;

  }

  switch ($part) {

    case 'date':

      return $date_format;

    case 'time':

      return $time_format;

    default:

      return trim($date_format . ' ' . $time_format);

  }

  return $format;

}

/**

 * Converts a date format to an ordered array of parts.

 *

 * Example:

 *   date_format_order('m/d/Y H:i')

 *   returns

 *     array(

 *       0 => 'month',

 *       1 => 'day',

 *       2 => 'year',

 *       3 => 'hour',

 *       4 => 'minute',

 *     );

 *

 * @param string $format

 *   A date format string.

 *

 * @return array

 *   An array of ordered elements from the given format string that

 *   includes only the date parts that exist in that string.

 */

function date_format_order($format) {

  $order = array();

  $max = strlen($format);

  for ($i = 0; $i < $max; $i++) {

    switch ($format[$i]) {

      case 'd':

      case 'j':

        $order[] = 'day';

        break;

      case 'F':

      case 'M':

      case 'm':

      case 'n':

        $order[] = 'month';

        break;

      case 'Y':

      case 'y':

        $order[] = 'year';

        break;

      case 'g':

      case 'G':

      case 'h':

      case 'H':

        $order[] = 'hour';

        break;

      case 'i':

        $order[] = 'minute';

        break;

      case 's':

        $order[] = 'second';

        break;

    }

  }

  return $order;

}

/**

 * Set up some constants.

 *

 * Includes standard date types, format strings, strict regex strings for ISO

 * and DATETIME formats (seconds are optional).

 *

 * The loose regex will find any variety of ISO date and time, with or

 * without time, with or without dashes and colons separating the elements,

 * and with either a 'T' or a space separating date and time.

 */

const DATE_ISO = 'date';

const DATE_UNIX = 'timestamp';

const DATE_FORMAT_ISO = "Y-m-d\TH:i:s";

const DATE_FORMAT_UNIX = "U";

const DATE_FORMAT_DATETIME = "Y-m-d H:i:s";

const DATE_FORMAT_ICAL = "Ymd\THis";

const DATE_FORMAT_ICAL_DATE = "Ymd";

const DATE_FORMAT_DATE = 'Y-m-d';

/**

 * Implements hook_help().

 */

function date_help($path, $arg) {

  switch ($path) {

    case 'admin/help#date':

      $output = '';

      if (module_exists('date_tools')) {

        $output .= '<h3>Date Tools</h3>' . t('Dates and calendars can be complicated to set up. The !date_wizard makes it easy to create a simple date content type and with a date field. ', array('!date_wizard' => l(t('Date wizard'), 'admin/config/date/tools/date_wizard')));

      }

      else {

        $output .= '<h3>Date Tools</h3>' . t('Dates and calendars can be complicated to set up. If you enable the Date Tools module, it provides a Date Wizard that makes it easy to create a simple date content type with a date field. ');

      }

      $output .= '<h2>More Information</h2><p>' . t('Complete documentation for the Date and Date API modules is available at <a href="@link">http://drupal.org/node/92460</a>.', array('@link' => 'http://drupal.org/node/262062')) . '</p>';

      return $output;

      break;

  }

}

/**

 * Implements hook_menu().

 *

 * Creates a 'Date API' section on the administration page for Date

 * modules to use for their configuration and settings.

 */

function date_api_menu() {

  $items['admin/config/date'] = array(

    'title' => 'Date API',

    'description' => 'Settings for modules the use the Date API.',

    'position' => 'left',

    'weight' => -10,

    'page callback' => 'system_admin_menu_block_page',

    'access arguments' => array('administer site configuration'),

    'file' => 'system.admin.inc',

    'file path' => drupal_get_path('module', 'system'),

  );

  return $items;

}

/**

 * Determines if the date element needs to be processed.

 *

 * Helper function to see if date element has been hidden by FAPI to see if it

 * needs to be processed or just pass the value through. This is needed since

 * normal date processing explands the date element into parts and then

 * reconstructs it, which is not needed or desirable if the field is hidden.

 *

 * @param array $element

 *   The date element to check.

 *

 * @return bool

 *   TRUE if the element is effectively hidden, FALSE otherwise.

 */

function date_hidden_element($element) {

  // @TODO What else needs to be tested to see if dates are hidden or disabled?

  if ((isset($element['#access']) && empty($element['#access']))

    || !empty($element['#programmed'])

    || in_array($element['#type'], array('hidden', 'value'))) {

    return TRUE;

  }

  return FALSE;

}

/**

 * Helper function for getting the format string for a date type.

 *

 * @param string $type

 *   A date type format name.

 *

 * @return string

 *   A date type format, like 'Y-m-d H:i:s'.

 */

function date_type_format($type) {

  switch ($type) {

    case DATE_ISO:

      return DATE_FORMAT_ISO;

    case DATE_UNIX:

      return DATE_FORMAT_UNIX;

    case DATE_DATETIME:

      return DATE_FORMAT_DATETIME;

    case DATE_ICAL:

      return DATE_FORMAT_ICAL;

  }

}

/**

 * Formats a time interval with granularity, including past and future context.

 *

 * @param object $date

 *   The current date object.

 * @param int $granularity

 *   (optional) Number of units to display in the string. Defaults to 2.

 *

 * @return string

 *   A translated string representation of the interval.

 *

 * @see format_interval()

 */

function date_format_interval($date, $granularity = 2, $display_ago = TRUE) {

  // If no date is sent, then return nothing.

  if (empty($date)) {

    return NULL;

  }

  $interval = REQUEST_TIME - $date->format('U');

  if ($interval > 0) {

    return $display_ago ? t('!time ago', array('!time' => format_interval($interval, $granularity))) :

      t('!time', array('!time' => format_interval($interval, $granularity)));

  }

  else {

    return format_interval(abs($interval), $granularity);

  }

}

/**

 * Implements hook_element_info().

 */

function date_api_element_info() {

  module_load_include('inc', 'date_api', 'date_api_elements');

  return _date_api_element_info();

}

/**

 * Implements hook_theme().

 */

function date_api_theme($existing, $type, $theme, $path) {

  $base = array(

    'file' => 'theme.inc',

    'path' => "$path/theme",

  );

  return array(

    'date_nav_title' => $base + array('variables' => array('granularity' => NULL, 'view' => NULL, 'link' => NULL, 'format' => NULL)),

    'date_timezone' => $base + array('render element' => 'element'),

    'date_select' => $base + array('render element' => 'element'),

    'date_select_element' => $base + array('render element' => 'element'),

    'date_textfield_element' => $base + array('render element' => 'element'),

    'date_part_hour_prefix' => $base + array('render element' => 'element'),

    'date_part_minsec_prefix' => $base + array('render element' => 'element'),

    'date_part_label_year' => $base + array('variables' => array('date_part' => NULL, 'element' => NULL)),

    'date_part_label_month' => $base + array('variables' => array('date_part' => NULL, 'element' => NULL)),

    'date_part_label_day' => $base + array('variables' => array('date_part' => NULL, 'element' => NULL)),

    'date_part_label_hour' => $base + array('variables' => array('date_part' => NULL, 'element' => NULL)),

    'date_part_label_minute' => $base + array('variables' => array('date_part' => NULL, 'element' => NULL)),

    'date_part_label_second' => $base + array('variables' => array('date_part' => NULL, 'element' => NULL)),

    'date_part_label_ampm' => $base + array('variables' => array('date_part' => NULL, 'element' => NULL)),

    'date_part_label_timezone' => $base + array('variables' => array('date_part' => NULL, 'element' => NULL)),

    'date_part_label_date' => $base + array('variables' => array('date_part' => NULL, 'element' => NULL)),

    'date_part_label_time' => $base + array('variables' => array('date_part' => NULL, 'element' => NULL)),

    'date_views_filter_form' => $base + array('template' => 'date-views-filter-form', 'render element' => 'form'),

    'date_calendar_day' => $base + array('variables' => array('date' => NULL)),

    'date_time_ago' => $base + array('variables' => array('start_date' => NULL, 'end_date' => NULL, 'interval' => NULL)),

    'datelist' => array(

      'render element' => 'element',

    ),

  );

}

/**

 * Returns HTML for a date selection form element.

 *

 * @param $variables

 *   An associative array containing:

 *   - element: An associative array containing the properties of the element.

 *     Properties used: #title, #value, #options, #description, #required,

 *     #attributes.

 *

 * @ingroup themeable

 */

function theme_datelist($variables) {

  $element = $variables['element'];

  $attributes = array();

  if (isset($element['#id'])) {

    $attributes['id'] = $element['#id'];

  }

  if (!empty($element['#attributes']['class'])) {

    $attributes['class'] = (array) $element['#attributes']['class'];

  }

  $attributes['class'][] = 'container-inline';

  return '<div' . new Attribute($attributes) . '>' . drupal_render_children($element) . '</div>';

}

/**

 * Function to figure out which local timezone applies to a date and select it.

 *

 * @param string $handling

 *   The timezone handling.

 * @param string $timezone

 *   (optional) A timezone string. Defaults to an empty string.

 *

 * @return string

 *   The timezone string.

 */

function date_get_timezone($handling, $timezone = '') {

  switch ($handling) {

    case 'date':

      $timezone = !empty($timezone) ? $timezone : drupal_get_user_timezone();

      break;

    case 'utc':

      $timezone = 'UTC';

      break;

    default:

      $timezone = drupal_get_user_timezone();

  }

  return $timezone > '' ? $timezone : drupal_get_user_timezone();

}

/**

 * Function to figure out which db timezone applies to a date and select it.

 *

 * @param string $handling

 *   The timezone handling.

 * @param string $timezone

 *   (optional) A timezone string. Defaults to an empty string.

 *

 * @return string

 *   The timezone string.

 */

function date_get_timezone_db($handling, $timezone = '') {

  switch ($handling) {

    case 'none':

      $timezone = drupal_get_user_timezone();

      break;

    default:

      $timezone = 'UTC';

      break;

  }

  return $timezone > '' ? $timezone : 'UTC';

}

/**

 * Helper function for converting back and forth from '+1' to 'First'.

 */

function date_order_translated() {

  return array(

    '+1' => t('First', array(), array('context' => 'date_order')),

    '+2' => t('Second', array(), array('context' => 'date_order')),

    '+3' => t('Third', array(), array('context' => 'date_order')),

    '+4' => t('Fourth', array(), array('context' => 'date_order')),

    '+5' => t('Fifth', array(), array('context' => 'date_order')),

    '-1' => t('Last', array(), array('context' => 'date_order_reverse')),

    '-2' => t('Next to last', array(), array('context' => 'date_order_reverse')),

    '-3' => t('Third from last', array(), array('context' => 'date_order_reverse')),

    '-4' => t('Fourth from last', array(), array('context' => 'date_order_reverse')),

    '-5' => t('Fifth from last', array(), array('context' => 'date_order_reverse')),

  );

}

/**

 * Creates an array of ordered strings, using English text when possible.

 */

function date_order() {

  return array(

    '+1' => 'First',

    '+2' => 'Second',

    '+3' => 'Third',

    '+4' => 'Fourth',

    '+5' => 'Fifth',

    '-1' => 'Last',

    '-2' => '-2',

    '-3' => '-3',

    '-4' => '-4',

    '-5' => '-5',

  );

}

/**

 * Tests validity of a date range string.

 *

 * @param string $string

 *   A min and max year string like '-3:+1'a.

 *

 * @return bool

 *   TRUE if the date range is valid, FALSE otherwise.

 */

function date_range_valid($string) {

  $matches = preg_match('@^(\-[0-9]+|[0-9]{4}):([\+|\-][0-9]+|[0-9]{4})$@', $string);

  return $matches < 1 ? FALSE : TRUE;

}

/**

 * Converts a min and max year into a string like '-3:+1'.

 *

 * @param array $years

 *   A numerically indexed array, containing a minimum and maximum year.

 *

 * @return string

 *   A min and max year string like '-3:+1'.

 */

function date_range_string($years) {

  $this_year = date_format(new DrupalDateTime(), 'Y');

  if ($years[0] < $this_year) {

    $min = '-' . ($this_year - $years[0]);

  }

  else {

    $min = '+' . ($years[0] - $this_year);

  }

  if ($years[1] < $this_year) {

    $max = '-' . ($this_year - $years[1]);

  }

  else {

    $max = '+' . ($years[1] - $this_year);

  }

  return $min . ':' . $max;

}

/**

 * Temporary helper to re-create equivalent of content_database_info().

 */

function date_api_database_info($field, $revision = FIELD_LOAD_CURRENT) {

  return array(

    'columns' => $field['storage']['details']['sql'][$revision],

    'table' => _field_sql_storage_tablename($field),

  );

}

/**

 * Implements hook_form_FORM_ID_alter() for system_regional_settings().

 *

 * Add a form element to configure whether or not week numbers are ISO-8601, the

 * default is FALSE (US/UK/AUS norm).

 */

function date_api_form_system_regional_settings_alter(&$form, &$form_state, $form_id) {

  $form['locale']['date_api_iso8601'] = array(

    '#type' => 'checkbox',

    '#title' => t('Use ISO-8601 week numbers'),

    '#default_value' => config('date_api.settings')->get('iso8601'),

    '#description' => t('IMPORTANT! If checked, First day of week MUST be set to Monday'),

  );

  $form['#validate'][] = 'date_api_form_system_settings_validate';

  $form['#submit'][] = 'date_api_form_system_settings_submit';

}

/**

 * Validate that the option to use ISO weeks matches first day of week choice.

 */

function date_api_form_system_settings_validate(&$form, &$form_state) {

  $form_values = $form_state['values'];

  if ($form_values['date_api_iso8601'] && $form_values['date_first_day'] != 1) {

    form_set_error('date_first_day', t('When using ISO-8601 week numbers, the first day of the week must be set to Monday.'));

  }

}

/**

 * Store the Date API 8601 week numbers setting.

 */

function date_api_form_system_settings_submit($form, &$form_state) {

  $form_values = $form_state['values'];

  config('date_api.settings')->set('iso8601', $form_values['date_api_iso8601'])->save();

}

/**

 * Creates an array of date format types for use as an options list.

 */

function date_format_type_options() {

  $options = array();

  $time = date_example_date();

  $format_types = system_get_date_types();

  if (!empty($format_types)) {

    foreach ($format_types as $type => $type_info) {

      $options[$type] = $type_info['title'] . ' (' . format_date($time->format('U'), $type) . ')';

    }

  }

  return $options;

}

/**

 * Creates an example date.

 *

 * This ensures a clear difference between month and day, and 12 and 24 hours.

 */

function date_example_date() {

  $now = new DrupalDateTime();

  if (date_format($now, 'M') == date_format($now, 'F')) {

    date_modify($now, '+1 month');

  }

  if (date_format($now, 'm') == date_format($now, 'd')) {

    date_modify($now, '+1 day');

  }

  if (date_format($now, 'H') == date_format($now, 'h')) {

    date_modify($now, '+12 hours');

  }

  return $now;

}

/**

 * Determine if a start/end date combination qualify as 'All day'.

 *

 * @param string $string1

 *   A string date in datetime format for the 'start' date.

 * @param string $string2

 *   A string date in datetime format for the 'end' date.

 * @param string $granularity

 *   (optional) The granularity of the date. Defaults to 'second'.

 * @param int $increment

 *   (optional) The increment of the date. Defaults to 1.

 *

 * @return bool

 *   TRUE if the date is all day, FALSE otherwise.

 */

function date_is_all_day($string1, $string2, $granularity = 'second', $increment = 1) {

  if (empty($string1) || empty($string2)) {

    return FALSE;

  }

  elseif (!in_array($granularity, array('hour', 'minute', 'second'))) {

    return FALSE;

  }

  preg_match('/([0-9]{4}-[0-9]{2}-[0-9]{2}) (([0-9]{2}):([0-9]{2}):([0-9]{2}))/', $string1, $matches);

  $count = count($matches);

  $date1 = $count > 1 ? $matches[1] : '';

  $time1 = $count > 2 ? $matches[2] : '';

  $hour1 = $count > 3 ? intval($matches[3]) : 0;

  $min1 = $count > 4 ? intval($matches[4]) : 0;

  $sec1 = $count > 5 ? intval($matches[5]) : 0;

  preg_match('/([0-9]{4}-[0-9]{2}-[0-9]{2}) (([0-9]{2}):([0-9]{2}):([0-9]{2}))/', $string2, $matches);

  $count = count($matches);

  $date2 = $count > 1 ? $matches[1] : '';

  $time2 = $count > 2 ? $matches[2] : '';

  $hour2 = $count > 3 ? intval($matches[3]) : 0;

  $min2 = $count > 4 ? intval($matches[4]) : 0;

  $sec2 = $count > 5 ? intval($matches[5]) : 0;

  if (empty($date1) || empty($date2)) {

    return FALSE;

  }

  if (empty($time1) || empty($time2)) {

    return FALSE;

  }

  $calendar = system_calendar();

  $tmp = $calendar->seconds('s', TRUE, $increment);

  $max_seconds = intval(array_pop($tmp));

  $tmp = $calendar->minutes('i', TRUE, $increment);

  $max_minutes = intval(array_pop($tmp));

  // See if minutes and seconds are the maximum allowed for an increment or the

  // maximum possible (59), or 0.

  switch ($granularity) {

    case 'second':

      $min_match = $time1 == '00:00:00'

        || ($hour1 == 0 && $min1 == 0 && $sec1 == 0);

      $max_match = $time2 == '00:00:00'

        || ($hour2 == 23 && in_array($min2, array($max_minutes, 59)) && in_array($sec2, array($max_seconds, 59)))

        || ($hour1 == 0 && $hour2 == 0 && $min1 == 0 && $min2 == 0 && $sec1 == 0 && $sec2 == 0);

      break;

    case 'minute':

      $min_match = $time1 == '00:00:00'

        || ($hour1 == 0 && $min1 == 0);

      $max_match = $time2 == '00:00:00'

        || ($hour2 == 23 && in_array($min2, array($max_minutes, 59)))

        || ($hour1 == 0 && $hour2 == 0 && $min1 == 0 && $min2 == 0);

      break;

    case 'hour':

      $min_match = $time1 == '00:00:00'

        || ($hour1 == 0);

      $max_match = $time2 == '00:00:00'

        || ($hour2 == 23)

        || ($hour1 == 0 && $hour2 == 0);

      break;

    default:

      $min_match = TRUE;

      $max_match = FALSE;

  }

  if ($min_match && $max_match) {

    return TRUE;

  }

  return FALSE;

}

/**

 * Helper function to round minutes and seconds to requested value.

 */

function date_increment_round(&$date, $increment) {

  // Round minutes and seconds, if necessary.

  if ($date instanceOf DrupalDateTime && $increment > 1) {

    $day = intval(date_format($date, 'j'));

    $hour = intval(date_format($date, 'H'));

    $second = intval(round(intval(date_format($date, 's')) / $increment) * $increment);

    $minute = intval(date_format($date, 'i'));

    if ($second == 60) {

      $minute += 1;

      $second = 0;

    }

    $minute = intval(round($minute / $increment) * $increment);

    if ($minute == 60) {

      $hour += 1;

      $minute = 0;

    }

    date_time_set($date, $hour, $minute, $second);

    if ($hour == 24) {

      $day += 1;

      $hour = 0;

      $year = date_format($date, 'Y');

      $month = date_format($date, 'n');

      date_date_set($date, $year, $month, $day);

    }

  }

  return $date;

}

/**

 * This function will replace ISO values that have the pattern 9999-00-00T00:00:00

 * with a pattern like 9999-01-01T00:00:00, to match the behavior of non-ISO

 * dates and ensure that date objects created from this value contain a valid month

 * and day. Without this fix, the ISO date '2020-00-00T00:00:00' would be created as

 * November 30, 2019 (the previous day in the previous month).

 *

 * @param string $iso_string

 *   An ISO string that needs to be made into a complete, valid date.

 *

 * @TODO Expand on this to work with all sorts of partial ISO dates.

 */

function date_make_iso_valid($iso_string) {

  // If this isn't a value that uses an ISO pattern, there is nothing to do.

  if (is_numeric($iso_string) || !preg_match(DATE_REGEX_ISO, $iso_string)) {

    return $iso_string;

  }

  // First see if month and day parts are '-00-00'.

  if (substr($iso_string, 4, 6) == '-00-00') {

    return preg_replace('/([\d]{4}-)(00-00)(T[\d]{2}:[\d]{2}:[\d]{2})/', '${1}01-01${3}', $iso_string);

  }

  // Then see if the day part is '-00'.

  elseif (substr($iso_string, 7, 3) == '-00') {

    return preg_replace('/([\d]{4}-[\d]{2}-)(00)(T[\d]{2}:[\d]{2}:[\d]{2})/', '${1}01${3}', $iso_string);

  }

  // Fall through, no changes required.

  return $iso_string;

}

/**

 * @file

 * SQL helper for Date API.

 *

 * @TODO

 * Add experimental support for sqlite: http://www.sqlite.org/lang_datefunc.html

 * and Oracle (http://psoug.org/reference/date_func.html and

 * http://psoug.org/reference/datatypes.html) date/time functions.

 */

/**

 * A helper function to do cross-database concatation of date parts.

 *

 * @param array $array

 *   An array of values to be concatonated in sql.

 *

 * @return string

 *   Correct sql string for database type.

 */

function date_sql_concat($array) {

  switch (db_driver()) {

    case 'mysql':

    case 'mysqli':

      return "CONCAT(" . implode(",", $array) . ")";

    case 'pgsql':

      return implode(" || ", $array);

  }

}

/**

 * Helper function to do cross-database NULL replacements

 *

 * @param array $array

 *   An array of values to test for NULL values.

 *

 * @return string

 *   SQL statement to return the first non-NULL value in the list.

 */

function date_sql_coalesce($array) {

  switch (db_driver()) {

    case 'mysql':

    case 'mysqli':

    case 'pgsql':

      return "COALESCE(" . implode(',', $array) . ")";

  }

}

/**

 * A helper function to do cross-database padding of date parts.

 *

 * @param string $str

 *   A string to apply padding to

 * @param int $size

 *   The size the final string should be

 * @param string $pad

 *   The value to pad the string with

 * @param string $side

 *   The side of the string to pad

 */

function date_sql_pad($str, $size = 2, $pad = '0', $side = 'l') {

  switch ($side) {

    case 'r':

      return "RPAD($str, $size, '$pad')";

    default:

      return "LPAD($str, $size, '$pad')";

  }

}

/**

   * Calculates the start and end dates for a calendar week.

   *

   * The dates are adjusted to use the chosen first day of week

   * for this site.

   *

   * @param int $week

   *   The week value.

   * @param int $year

   *   The year value.

   *

   * @return array

   *   An array containing the start and end dates of a week.

   */

function date_calendar_week_range($week, $year) {

  $min_date = new DrupalDateTime($year . '-01-01 00:00:00');

  // Move to the right week.

  date_modify($min_date, '+' . strval(7 * ($week - 1)) . ' days');

  // Move backwards to the first day of the week.

  $first_day = variable_get('date_first_day', 0);

  $day_wday = date_format($min_date, 'w');

  date_modify($min_date, '-' . strval((7 + $day_wday - $first_day) % 7) . ' days');

  // Move forwards to the last day of the week.

  $max_date = clone($min_date);

  date_modify($max_date, '+7 days');

  if (date_format($min_date, 'Y') != $year) {

    $min_date = new DrupalDateTime($year . '-01-01 00:00:00');

  }

  return array($min_date, $max_date);

}

/**

 * Calculates the start and end dates for an ISO week.

 *

 * @param int $week

 *   The week value.

 * @param int $year

 *   The year value.

 *

 * @return array

 *   An array containing the start and end dates of an

 *   ISO week.

 */

function date_iso_week_range($week, $year) {

  // Get to the last ISO week of the previous year.

  $min_date = new DrupalDateTime(($year - 1) . '-12-28 00:00:00');

  // Find the first day of the first ISO week in the year.

  date_modify($min_date, '+1 Monday');

  // Jump ahead to the desired week for the beginning of the week range.

  if ($week > 1) {

    date_modify($min_date, '+ ' . ($week - 1) . ' weeks');

  }

  // Move forwards to the last day of the week.

  $max_date = clone($min_date);

  date_modify($max_date, '+7 days');

  return array($min_date, $max_date);

}

/**

 * The number of calendar weeks in a year.

 *

 * PHP week functions return the ISO week, not the calendar week.

 *

 * @param int $year

 *   A year value.

 *

 * @return int

 *   Number of calendar weeks in selected year.

 */

function date_weeks_in_year($year) {

  $date = new DrupalDateTime(($year + 1) . '-01-01 12:00:00', 'UTC');

  date_modify($date, '-1 day');

  return self::calendar_week($date->format('Y-m-d'));

}

 /**

 * Identifies the number of ISO weeks in a year for a date.

 *

 * December 28 is always in the last ISO week of the year.

 *

 * @param mixed $date

 *   (optional) A date object, timestamp, or a date string.

 *   Defaults to current date.

 *

 * @return integer

 *   The number of ISO weeks in a year.

 */

function date_iso_weeks_in_year($date = NULL) {

  if (!$date instanceOf DrupalDateTime) {

    $date = new DrupalDateTime($date);

  }

  if ($date instanceOf DrupalDateTime && !$date->hasErrors()) {

    date_date_set($date, $date->format('Y'), 12, 28);

    return $date->format('W');

  }

  return NULL;

}

/**

 * The calendar week number for a date.

 *

 * PHP week functions return the ISO week, not the calendar week.

 *

 * @param string $date

 *   A date string in the format Y-m-d.

 *

 * @return int

 *   The calendar week number.

 */

function date_calendar_week($date) {

  $date = substr($date, 0, 10);

  $parts = explode('-', $date);

  $date = new DrupalDateTime($date . ' 12:00:00', 'UTC');

  // If we are using ISO weeks, this is easy.

  if (config('date_api.settings')->get('iso8601')) {

    return intval($date->format('W'));

  }

  $year_date = new DrupalDateTime($parts[0] . '-01-01 12:00:00', 'UTC');

  $week = intval($date->format('W'));

  $year_week = intval(date_format($year_date, 'W'));

  $date_year = intval($date->format('o'));

  // Remove the leap week if it's present.

  if ($date_year > intval($parts[0])) {

    $last_date = clone($date);

    date_modify($last_date, '-7 days');

    $week = date_format($last_date, 'W') + 1;

  }

  elseif ($date_year < intval($parts[0])) {

    $week = 0;

  }

  if ($year_week != 1) {

    $week++;

  }

  // Convert to ISO-8601 day number, to match weeks calculated above.

  $iso_first_day = 1 + (variable_get('date_first_day', 0) + 6) % 7;

  // If it's before the starting day, it's the previous week.

  if (intval($date->format('N')) < $iso_first_day) {

    $week--;

  }

  // If the year starts before, it's an extra week at the beginning.

  if (intval(date_format($year_date, 'N')) < $iso_first_day) {

    $week++;

  }

  return $week;

}