<?php
// $Id: duration_element.module,v 1.5 2008/05/27 01:47:46 jpetso Exp $

/**
 * @file
 * A form element for entering time durations.
 *
 * Copyright 2007, 2008 by Jakob Petsovits <jpetso@gmx.at>
 * Distributed under the GNU General Public Licence version 2 or higher,
 * as published by the FSF on http://www.gnu.org/copyleft/gpl.html
 */

/**
 * Implementation of hook_elements():
 * Register the duration widget with the Forms API and set default values.
 */
function duration_element_elements() {
  return array(
    'duration_combo' => array(
      '#input' => TRUE,
      '#largest_metric' => 'years',
      '#smallest_metric' => 'seconds',
      '#display_inline' => TRUE,
      '#size' => 3, // size of each input textbox
      '#maxlength' => 4, // maxlength of each input textbox
      '#process' => array('duration_element_combo_process'),
    ),
    'duration_select' => array(
      '#input' => TRUE,
      '#options' => array(),
      '#format_callback' => 'duration_format_list',
      '#format_callback_arguments' => array(),
      '#process' => array('duration_element_select_process'),
    ),
  );
}


/**
 * Value callback, so that the #default_value is not directly assigned
 * but transformed into an array for the nested "$metric" elements.
 * form.inc produces a nasty error if we don't do that.
 */
function form_type_duration_combo_value($element, $edit = FALSE) {
  if (func_num_args() == 1) {
    if (is_object($element['#default_value'])) {
      $duration = $element['#default_value'];
      // Cut off metrics that are not provided as input fields.
      $duration->set_granularity(
        $element['#smallest_metric'], $element['#largest_metric']
      );
    }
    else { // no default value, use a brand new duration object instead
      $duration = duration_create();
    }

    $values = array(
      'type' => $duration->type(),
    );
    foreach ($duration->to_array() as $metric => $value) {
      $values[$metric] = $value;
    }
  }
  else {
    $values = $edit;
    $values['type'] = isset($values['months']) ? 'months' : 'weeks';
  }
  return $values;
}

/**
 * The 'process' callback for 'duration_combo' form elements.
 * Called after defining the form and while building it.
 */
function duration_element_combo_process($element) {
  if (isset($element['#element_validate'])) {
    // Before the element user gets to do his validation, make sure we do ours.
    array_unshift($element['#element_validate'], 'duration_element_combo_validate');
  }
  else {
    $element['#element_validate'] = array('duration_element_combo_validate');
  }
  $type = $element['#value']['type']; // 'weeks' or 'months'

  // Use the format that the duration object itself is using
  // (e.g. 'P1D' for 'months', 'P0W1D' for 'weeks') - even if that overrides
  // the element creator's setting. We might lose data otherwise, and anyways
  // the element creator should make sure to pass an appropriately typed object.
  if ($type == 'weeks' && $element['#smallest_metric'] == 'months') {
    $element['#smallest_metric'] = 'years'; // are larger than months, weeks are not
  }
  if ($type == 'months' && $element['#smallest_metric'] == 'weeks') {
    $element['#smallest_metric'] = 'months';
  }
  if ($type == 'weeks' && $element['#largest_metric'] == 'months') {
    $element['#largest_metric'] = 'weeks';
  }
  if ($type == 'months' && $element['#largest_metric'] == 'weeks') {
    $element['#largest_metric'] = 'days'; // are smaller than weeks, months are not
  }

  $metrics = duration_metrics();
  $used_metrics = array();
  $encountered_largest_metric = FALSE;

  foreach ($metrics as $metric) {
    if ($metric == $element['#largest_metric']) {
      $encountered_largest_metric = TRUE;
    }
    if ($encountered_largest_metric) {
      if (($metric == 'months' && $type == 'weeks')
          || ($metric == 'weeks' && $type == 'months')) {
        // doesn't belong in here, don't include this metric
      }
      else {
        $used_metrics[$metric] = duration_metric_t($metric);
      }
    }
    if ($metric == $element['#smallest_metric']) {
      break;
    }
  }

  $element['#tree'] = TRUE; // so that we can nest child input elements
  $element['#used_metrics'] = $used_metrics; // save for the validation callback

  foreach ($used_metrics as $metric => $metric_t) {
    if ($metric != $element['#smallest_metric']) {
      // Some additional space between the text and the next textfield.
      $metric_t = '<span style="margin-right: 0.8em;">' . $metric_t . '</span>';
    }
    $element[$metric] = array(
      '#type' => 'textfield',
      '#default_value' => $element['#value'][$metric],
      '#size' => $element['#size'],
      '#maxlength' => $element['#maxlength'],
      '#prefix' => '<div class="container-inline">',
      '#suffix' => $metric_t . '</div>',
    );
  }

  // Don't have a maxlength in the parent element, as Form API tries to
  // perform string operations if we've got that property.
  unset($element['#maxlength']);

  return $element;
}

/**
 * The 'validate' callback for 'duration_combo' form elements.
 * Called after values are assigned, before form validate and submit are called.
 */
function duration_element_combo_validate(&$element, &$form_state) {
  $duration = duration_create();

  foreach ($element['#used_metrics'] as $metric => $metric_t) {
    $value = $element[$metric]['#value'];

    if ($value === '') {
      $value = 0;
    }
    if (!is_numeric($value) || $value < 0) {
      form_error($element[$metric],
        t('The "@metric" value in %widget must be greater or equal 0.',
        array('@metric' => $metric_t, '%widget' => $element['#title']))
      );
      $error_set = TRUE;
    }
    else {
      $duration->set_value($metric, $value);
    }
  }
  if ($element['#required'] && $duration->to_single_metric('seconds') == 0) {
    form_error($element,
      t('A non-zero duration is required for %widget.',
      array('%widget' => $element['#title']))
    );
  }
  form_set_value($element, $duration, $form_state);

  // Altering the element itself is slightly non-standard (..."a hack"),
  // but allows access to the modified value in subsequent element validators.
  $element['#value'] = $duration;
}


/**
 * Value callback, so that the #default_value is not directly assigned
 * but transformed into an array for the nested 'select' element.
 * form.inc produces a nasty error if we don't do that.
 */
function form_type_duration_select_value($element, $edit = FALSE) {
  if (func_num_args() == 1) {
    return array('select' => $element['#default_value']);
  }
}

/**
 * The 'process' callback for the 'duration_select' element.
 * Called after defining the form and while building it.
 */
function duration_element_select_process($element) {
  if (isset($element['#element_validate'])) {
    // Before the element user gets to do his validation, make sure we do ours.
    array_unshift($element['#element_validate'], 'duration_element_select_validate');
  }
  else {
    $element['#element_validate'] = array('duration_element_select_validate');
  }
  $options = array();

  foreach ($element['#options'] as $key => $duration) {
    if (!is_object($duration)) {
      continue;
    }
    $function = $element['#format_callback'];
    $args = $element['#format_callback_arguments'];
    array_unshift($args, $duration); // $duration as first argument
    $options[$key] = call_user_func_array($function, $args);
  }
  $element['#tree'] = TRUE; // so that we can nest child input elements

  $element['select'] = array(
    '#type' => 'select',
    '#default_value' => isset($element['#default_value'])
                        ? $element['#default_value']
                        : reset(array_keys($options)),
    '#options' => $options,
    '#required' => $element['#required'],
  );
  return $element;
}

/**
 * The 'validate' callback for the 'duration_select' element.
 * Called after values are assigned, before form validate and submit are called.
 */
function duration_element_select_validate(&$element, &$form_state) {
  // Altering the element itself is slightly non-standard (..."a hack"),
  // but allows access to the modified value in subsequent element validators.
  $element['#value'] = $element['select']['#value'];
  form_set_value($element, $element['#value'], $form_state);
}


/**
 * Implementation of hook_theme().
 */
function duration_element_theme() {
  return array(
    'duration_combo' => array('arguments' => array('element' => NULL)),
    'duration_select' => array('arguments' => array('element' => NULL)),
  );
}

/**
 * Theme the duration element.
 */
function theme_duration_combo($element) {
  // class="container-inline" makes child widgets align horizontally.
  $children = ($element['#display_inline'])
    ? '<div class="container-inline">' . $element['#children'] . '</div>'
    : $element['#children'];

  return theme('form_element', $element, $children);
}

function theme_duration_select($element) {
  // class="container-inline" not only makes child widgets align horizontally,
  // it also reduces the unnecessarily large space between title and element.
  return theme('form_element', $element,
    '<div class="container-inline">' . $element['#children'] . '</div>'
  );
}