<?php
// $Id: handlers.inc,v 1.25 2008-02-18 06:23:13 merlinofchaos Exp $
/**
 * @file handlers.inc
 * Defines the various handler objects to help build and display views.
 */

/**
 * Instantiate and construct a new handler
 */
function _views_create_handler($definition) {
//  vpr('Instantiating handler ' . $definition['handler']);
  $handler = new $definition['handler'];
  $handler->set_definition($definition);
  // let the handler have something like a constructor.
  if (isset($definition['arguments'])) {
    call_user_func_array(array($handler, 'construct'), $definition['arguments']);
  }
  else {
    $handler->construct();
  }

  return $handler;
}

/**
 * Prepare a handler's data by checking defaults and such.
 */
function _views_prepare_handler($definition, $data, $field) {
  foreach (array('group', 'title', 'help') as $key) {
    // First check the field level
    if (!isset($definition[$key]) && !empty($data[$field][$key])) {
      $definition[$key] = $data[$field][$key];
    }
    // Then if that doesn't work, check the table level
    if (!isset($definition['table'][$key]) && !empty($data['table'][$key])) {
      $definition[$key] = $data['table'][$key];
    }
  }

  return _views_create_handler($definition);
}

/**
 * Fetch a handler to join one table to a primary table from the data cache
 */
function views_get_table_join($table, $primary_table) {
  $data = views_fetch_data($table);
  if (isset($data['table']['join'][$primary_table])) {
    $h = $data['table']['join'][$primary_table];
    $handler = new $h['handler'];
    if (isset($h['arguments'])) {
      call_user_func_array(array($handler, 'construct'), $h['arguments']);
    }
    return $handler;
  }
  // DEBUG -- identify missing handlers
  vpr("Missing join: $table $primary_table");
}

/**
 * @defgroup views_join_handlers Views' join handlers
 * @{
 * Handlers to tell Views how to join tables together.

 * Here is how you do complex joins:
 *
 * @code
 * class views_join_complex extends views_join {
 *   // PHP 4 doesn't call constructors of the base class automatically from a
 *   // constructor of a derived class. It is your responsibility to propagate
 *   // the call to constructors upstream where appropriate.
 *   function construct($left_table, $left_field, $field, $extra = array(), $type = 'LEFT') {
 *     parent::construct($left_table, $left_field, $field, $extra, $type);
 *   }
 *
 *   function join($table, &$query) {
 *     $output = parent::join($table, $query);
 *   }
 *   $output .= "AND foo.bar = baz.boing";
 *   return $output;
 * }
 * @endcode
 */
/**
 * A function class to represent a join and create the SQL necessary
 * to implement the join.
 *
 * This is the Delegation pattern. If we had PHP5 exclusively, we would
 * declare this an interface.
 *
 * Extensions of this class can be used to create more interesting joins.
 */
class views_join {
  /**
   * Construct the views_join object.
   */
  function construct($table, $left_table, $left_field, $field, $extra = array(), $type = 'LEFT') {
    $this->table = $table;
    $this->left_table = $left_table;
    $this->left_field = $left_field;
    $this->field = $field;
    $this->extra = $extra;
    $this->type = strtoupper($type);
  }

  /**
   * Build the SQL for the join this object represents.
   */
  function join($table, &$query) {
    $left = $query->get_table_info($this->left_table);
    $output = " $this->type JOIN {" . $this->table . "} $table[alias] ON $left[alias].$this->left_field = $table[alias].$this->field";

    // Tack on the extra.
    if (isset($extra)) {
      foreach ($extra as $field => $value) {
        $output .= " AND $table[alias].$this->field";
        if (is_array($value) && !empty($value)) {
          $output .= " IN ('". implode("','", $value) ."')";
        }
        else if ($value !== NULL) {
          $output .= " = '$value'";
        }
      }
    }
    return $output;
  }
}

/**
 * @}
 */

/**
 * Base handler, from which all the other handlers are derived.
 * It creates a common interface to create consistency amongst
 * handlers and data.
 *
 * The default handler has no constructor, so there's no need to jank with
 * parent::views_handler() here.
 *
 * This class would be abstract in PHP5, but PHP4 doesn't understand that.
 *
 */
class views_handler extends views_object {
  /**
   * A constructor for the handler base object
   *
   * This should be overridden to provide for a consistent constructor
   * mechanism.
   */
  function construct() { }

  /**
   * init the handler with necessary data.
   * @param $view
   *   The $view object this handler is attached to.
   * @param $data
   *   The item from the database; the actual contents of this will vary
   *   based upon the type of handler.
   */
  function init(&$view, $options) {
    $this->view = &$view;
    $this->options = &$options;

    // This exist on most handlers, but not all. So they are still optional.
    if (isset($options['table'])) {
      $this->table = $options['table'];
    }

    if (isset($options['field'])) {
      $this->field = $options['field'];
      if (!isset($this->real_field)) {
        $this->real_field = $options['field'];
      }
    }

    if (isset($options['relationship'])) {
      $this->relationship = $options['relationship'];
    }
    else {
      $this->relationship = NULL;
    }

    if (!empty($view->query)) {
      $this->query = &$view->query;
    }
  }

  /**
   * Provide defaults for the handler.
   */
  function options(&$option) { }

  /**
   * Provide a form for setting options.
   */
  function options_form(&$form, &$form_state) { }

  /**
   * Validate the options form.
   */
  function options_validate($form, &$form_state) { }

  /**
   * Perform any necessary changes to the form values prior to storage.
   * There is no need for this function to actually store the data.
   */
  function options_submit($form, &$form_state) { }

  /**
   * Add this handler into the query.
   *
   * If we were using PHP5, this would be abstract.
   */
  function query() { }

  /**
   * Ensure the main table for this handler is in the query. This is used
   * a lot.
   */
  function ensure_my_table() {
    if (!isset($this->alias)) {
      $this->table_alias = $this->query->ensure_table($this->table, $this->relationship);
    }
    return $this->table_alias;
  }

  /**
   * Provide text for the administrative summary
   */
  function admin_summary() { }

  /**
   * Determine if the argument needs a style plugin.
   *
   * @return TRUE/FALSE
   */
  function needs_style_plugin() { return FALSE; }
}

/**
 * @defgroup views_relationship_handlers Views' relationship handlers
 * @{
 * Handlers to tell Views how to create alternate relationships.
 */

/**
 * Simple relationship handler that allows a new version of the primary table
 * to be linked in.
 */
class views_handler_relationship extends views_handler {
  /**
   * Called to implement a relationship in a query.
   */
  function query() {
    $alias = $this->table . '_' . $this->field . '_' . $this->relationship;
    return $this->query->add_relationship($alias, new views_join($this->view->primary_table, $this->table, $this->real_field, $this->primary_field), $this->relationship);
  }
}

/**
 * @}
 */

/**
 * @defgroup views_field_handlers Views' field handlers
 * @{
 * Handlers to tell Views how to build and display fields.
 *
 */

/**
 * Base field handler that has no options and renders an unformatted field.
 */
class views_handler_field extends views_handler {
  var $field_alias = 'unknown';

  /**
   * Construct a new field handler.
   */
//  function construct($click_sortable = FALSE, $additional_fields = array()) {
  function construct() {
    $this->click_sortable = !empty($this->definition['click sortable']);
    $this->additional_fields = array();
    if (!empty($this->definition['additional fields'])) {
      $this->additional_fields = $this->definition['additional fields'];
    }
  }

  /**
   * Called to add the field to a query.
   */
  function query() {
    $this->ensure_my_table();
    // Add the field.
    $this->field_alias = $this->query->add_field($this->table_alias, $this->real_field);

    // Add any additional fields we are given.
    if (!empty($this->additional_fields) && is_array($this->additional_fields)) {
      foreach ($this->additional_fields as $field) {
        $this->aliases[$field] = $this->query->add_field($this->table_alias, $field);
      }
    }
  }

  /**
   * Called to determine what to tell the clicksorter.
   */
  function click_sort() {
    return "$this->field_alias";
  }

  /**
   * Render the field.
   *
   * @param $values
   *   The values retrieved from the database.
   */
  function render($values) {
    $value = $values->{$this->field_alias};
    return check_plain($value);
  }
}

/**
 * A handler to provide proper displays for dates.
 */
class views_handler_field_date extends views_handler_field {
  /**
   * Fill in default options.
   */
  function options(&$options) {
    parent::options($options);
    $options['date_format'] = 'small';
    $options['custom_date_format'] = '';
  }

  function options_form(&$form, &$form_state) {
    $form['date_format'] = array(
      '#type' => 'select',
      '#title' => t('Date format'),
      '#options' => array(
        'small' => t('Small'),
        'medium' => t('Medium'),
        'large' => t('Large'),
        'custom' => t('Custom'),
        'time ago' => t('Time ago'),
      ),
      '#default_value' => isset($this->options['date_format']) ? $this->options['date_format'] : 'small',
    );
    $form['custom_date_format'] = array(
      '#type' => 'textfield',
      '#title' => t('Custom date format'),
      '#description' => t('If "Custom", see <a href="http://us.php.net/manual/en/function.date.php">the PHP docs</a> for date formats. If "Time ago" this is the the number of different units to display, which defaults to two.'),
      '#default_value' => isset($this->options['custom_date_format']) ? $this->options['custom_date_format'] : '',
    );
  }

  function render($values) {
    $value = $values->{$this->field_alias};
    $format = $this->options['date_format'];
    if ($format == 'custom') {
      $custom_format = $this->custom_date_format;
    }

    switch ($format) {
      case 'time ago':
        return $value ? t('%time ago', array('%time' => format_interval(time() - $value, is_numeric($custom_format) ? $custom_format : 2))) : theme('views_nodate');
      case 'custom':
        return $value ? format_date($value, $format, $custom_format) : theme('views_nodate');
      default:
        return $value ? format_date($value, $format) : theme('views_nodate');
    }
  }
}

/**
 * A handler to provide proper displays for dates.
 *
 * Allows for display of true/false, yes/no, on/off.
 */
class views_handler_field_boolean extends views_handler_field {
  function options(&$options) {
    parent::options($options);
    $options['type'] = 'yes-no';
    $options['not'] = FALSE;
  }

  function options_form(&$form, &$form_state) {
    $form['type'] = array(
      '#type' => 'select',
      '#title' => t('Output format'),
      '#options' => array(
        'yes-no' => t('Yes/No'),
        'true-false' => t('True/False'),
        'on-off' => t('On/Off'),
      ),
      '#default_value' => $this->options['type'],
    );
    $form['not'] = array(
      '#type' => 'checkbox',
      '#title' => t('Reverse'),
      '#description' => t('If checked, true will be displayed as false.'),
      '#default_value' => $this->options['not'],
    );
  }

  function render($values) {
    $value = $values->{$this->field_alias};
    if (!empty($this->options['not'])) {
      $value = !$value;
    }

    switch ($this->options['type']) {
      case 'yes-no':
      default:
        return $value ? t('Yes') : t('No');
      case 'true-false':
        return $value ? t('True') : t('False');
      case 'on-off':
        return $value ? t('On') : t('Off');
    }
  }
}

/**
 * A handler to run a field through check_markup, using a companion
 * format field.
 */
class views_handler_field_markup extends views_handler_field {
  /**
   * Constructor; calls to base object constructor.
   */
  function construct() {
    $this->format = $this->definition['format'];

    $this->additional_fields = array();
    if (!is_numeric($this->format)) {
      $this->additional_fields[] = $this->format;
    }
  }

  function render($values) {
    $value = $values->{$this->field_alias};
    $format = is_numeric($this->format) ? $this->format : $values->{$this->aliases[$this->format]};
    return check_markup($value, $format, FALSE);
  }
}

/**
 * @}
 */

/**
 * @defgroup views_sort_handlers Views' sort handlers
 * @{
 * Handlers to tell Views how to sort queries
 */
/**
 * Base sort handler that has no options and performs a simple sort
 */
class views_handler_sort extends views_handler {
  /**
   * Called to add the sort to a query.
   */
  function query() {
    $this->ensure_my_table();
    // Add the field.
    $this->query->add_orderby($this->table_alias, $this->real_field, $this->options['order']);
  }

  /**
   * Set defaults for new handler
   */
  function options(&$options) {
    parent::options($options);
    $options['order'] = 'ASC';
  }

  /**
   * Display whether or not the sort order is ascending or descending
   */
  function admin_summary() {
    switch ($this->options['order']) {
      case 'ASC':
      case 'asc':
      default:
        $type = t('asc');
        break;
      case 'DESC';
      case 'desc';
        $type = t('desc');
        break;
    }
    return '<span class="views-ascending"><span>' . $type . '</span></span>';
  }

  /**
   * Basic options for all sort criteria
   */
  function options_form(&$form, &$form_state) {
    $form['order'] = array(
      '#type' => 'radios',
      '#title' => t('Sort order'),
      '#options' => array('ASC' => t('Ascending'), 'DESC' => t('Descending')),
      '#default_value' => $this->options['order'],
    );
  }
}

/**
 * Base sort handler that has no options and performs a simple sort
 */
class views_handler_sort_formula extends views_handler_sort {
  /**
   * Constructor to take the formula this sorts on.
   *
   * @param $formula
   *   The formula used to sort. If an array, may be keyed by database type. If
   *   used, 'default' MUST be defined.
   */
//  function construct($formula) {
  function construct() {
    $this->formula = $this->definition['formula'];
    if (is_array($this->formula) && !isset($this->formula['default'])) {
      $this->error = t('views_handler_sort_formula missing default: @formula', array('@formula' => var_export($this->formula, TRUE)));
    }
    parent::construct();
  }
  /**
   * Called to add the sort to a query.
   */
  function query() {
    if (is_array($this->formula)) {
      global $db_type;
      if (isset($this->formula[$db_type])) {
        $formula = $this->formula[$db_type];
      }
      else {
        $formula = $this->formula['default'];
      }
    }
    else {
      $formula = $this->formula;
    }
    $this->ensure_my_table();
    // Add the field.
    $this->add_orderby(NULL, $this->formula, $this->options['order'], $this->table_alias . '_' . $this->field);
  }
}

/**
 * @}
 */

/**
 * @defgroup views_filter_handlers Views' filter handlers
 * @{
 * Handlers to tell Views how to filter queries.
 */

/**
 * Base class for filters.
 */
class views_handler_filter extends views_handler {
  /**
   * Provide some extra help to get the operator/value easier to use.
   */
  function init(&$view, $options) {
    parent::init($view, $options);

    if (!empty($options['operator']['operator'])) {
      $this->operator = $options['operator']['operator'];
    }
    else {
      $this->operator = $options['operator'];
    }

    if (!empty($options['value']['value'])) {
      $this->value = $options['value']['value'];
    }
    else {
      $this->value = $options['value'];
    }
  }

  /**
   * Provide a simple default initializer -- should be overridden.
   */
  function options(&$options) {
    parent::options($options);
    $options['operator'] = '=';
    $options['value'] = '';
    $options['group'] = 0;
  }

  /**
   * Display the filter on the administrative summary
   */
  function admin_summary() {
    return check_plain($this->operator) . ' ' . check_plain($this->value);
  }

  /**
   * Provide the basic form which calls through to subforms.
   * If overridden, it is best to call through to the parent.
   */
  function options_form(&$form, &$form_state) {
    $this->operator_form($form['operator'], $form_state);
    $form['operator']['#prefix'] = '<div class="views-left-30">';
    $form['operator']['#suffix'] = '</div>';

    $this->value_form($form['value'], $form_state);
    $form['value']['#prefix'] = '<div class="views-left-50">';
    $form['value']['#suffix'] = '</div>';
  }

  /**
   * Simple validate handler
   */
  function options_validate(&$form, &$form_state) {
    $this->operator_validate($form['operator'], $form_state);
    $this->value_validate($form['value'], $form_state);
  }

  /**
   * Simple submit handler
   */
  function options_submit(&$form, &$form_state) {
    $this->operator_submit($form['operator'], $form_state);
    $this->value_submit($form['value'], $form_state);
  }

  /**
   * Provide a form for setting the operator.
   *
   * This should be overridden by all child classes, and it must
   * define $form['operator'];
   */
  function operator_form(&$form, &$form_state) { $form['operator'] = array(); }

  /**
   * Validate the operator form.
   */
  function operator_validate($form, &$form_state) { }

  /**
   * Perform any necessary changes to the form values prior to storage.
   * There is no need for this function to actually store the data.
   */
  function operator_submit($form, &$form_state) { }

  /**
   * Provide a form for setting options.
   *
   * This should be overridden by all child classes and it must
   * define $form['value']
   */
  function value_form(&$form, &$form_state) { $form['value'] = array(); }

  /**
   * Validate the options form.
   */
  function value_validate($form, &$form_state) { }

  /**
   * Perform any necessary changes to the form values prior to storage.
   * There is no need for this function to actually store the data.
   */
  function value_submit($form, &$form_state) { }

  /**
   * Add this filter to the query.
   *
   * Due to the nature of fapi, the value and the operator have an unintended
   * level of indirection. You will find them in $this->operator
   * and $this->value respectively.
   */
  function query() {
    $this->ensure_my_table();
    $this->query->add_where($this->options['group'], "$this->table_alias.$this->real_field " . $this->operator . " '%s'", $this->value);
  }
}

/**
 * Simple filter to handle equal to / not equal to filters
 */
class views_handler_filter_equality extends views_handler_filter {
  /**
   * Provide basic defaults for the equality operator
   */
  function options(&$options) {
    parent::options($options);
    $options['operator'] = '=';
    $options['value'] = '';
  }

  /**
   * Provide simple equality operator
   */
  function operator_form(&$form, &$form_state) {
    $form['operator'] = array(
      '#type' => 'radios',
      '#title' => t('Operator'),
      '#default_value' => $this->operator,
      '#options' => array(
        '=' => t('Is equal to'),
        '!=' => t('Is not equal to'),
      ),
    );
  }

  /**
   * Provide a simple textfield for equality
   */
  function value_form(&$form, &$form_state) {
    $form['value'] = array(
      '#type' => 'textfield',
      '#title' => t('Value'),
      '#size' => 30,
      '#default_value' => $this->value,
    );
  }
}

/**
 * Simple filter to handle matching of boolean values
 */
class views_handler_filter_boolean_operator extends views_handler_filter {
  function construct() {
    $this->value_value = t('True');
    if (isset($this->definition['label'])) {
      $this->value_value = $this->definition['label'];
    }
    parent::construct();
  }

  function options(&$options) {
    parent::options($options);
    $options['operator'] = '=';
  }

  function operator_form(&$form, &$form_state) {
    $form['operator'] = array(
      '#type' => 'radios',
      '#default_value' => $this->operator,
      '#options' => array(
        '=' => t('Is'),
        '<>' => t('Is not'),
      ),
    );
  }
  function value_form(&$form, &$form_state) {
    $form['value'] = array(
      '#type' => 'textfield',
      '#disabled' => TRUE,
      '#value' => $this->value_value,
    );
  }

  function admin_summary() {
    return check_plain($this->operator) . ' ' . check_plain($this->value_value);
  }

  function query() {
    // @todo this should actually reverse the operator so it can compare against 0.
    $this->ensure_my_table();
    $this->query->add_where($this->options['group'], "$this->table_alias.$this->real_field " . $this->operator . " 1");
  }

}

/**
 * Simple filter to handle matching of multiple options selectable via checkboxes
 */
class views_handler_filter_in_operator extends views_handler_filter {
  function construct() {
    parent::construct();
    $this->value_title = t('Options');
    $this->value_options = array(t('Yes'), t('No'));
  }

  function options(&$options) {
    parent::options($options);
    $options['operator'] = 'in';
    $options['value'] = 0;
  }

  /**
   * Provide inclusive/exclusive matching
   */
  function operator_form(&$form, &$form_state) {
    $form['operator'] = array(
      '#type' => 'radios',
      '#title' => t('Operator'),
      '#default_value' => ($this->operator) ? $this->operator : 'in',
      '#options' => array(
        'in' => t('Is one of'),
        'not in' => t('Is not one of'),
      ),
    );
  }

  function value_form(&$form, &$form_state) {
    $form['value'] = array(
      '#type' => 'checkboxes',
      '#required' => TRUE,
      '#title' => $this->value_title,
      '#options' => $this->value_options,
      '#default_value' => (array) $this->value,
    );
  }

  function value_submit($form, &$form_state) {
    // This is so deeply deeply deeply nested due to the way the form is layered.
    $form_state['values']['options']['value'] = array_filter($form_state['values']['options']['value']);
  }

  function admin_summary() {
    if (count($this->value) == 1) {
      // If there is only one, show it as an =.
      $keys = array_keys($this->value);
      $value = check_plain($this->value_options[array_shift($keys)]);

      return ($this->operator == 'in' ? '=' : '<>') . ' ' . $value;
    }
    $output = '';
    foreach ($this->value as $value) {
      if ($output) {
        $output .= ', ';
      }
      if (strlen($output) > 8) {
        $output .= '...';
        break;
      }
      $output .= check_plain($this->value_options[$value]);
    }

    return check_plain($this->operator) . ' ' . $output;
  }

  function query() {
    $this->ensure_my_table();
    $replace = array_fill(0, sizeof($this->value), "'%s'");
    $in = ' (' . implode(", ", $replace) . ')';
    $this->query->add_where($this->options['group'], "$this->table_alias.$this->real_field " . $this->operator . $in, $this->value);
  }
}

/**
 * @}
 */

/**
 * @defgroup views_argument_handlers Handlers for arguments
 * @{
 */
/**
 * Base class for arguments.
 *
 * The basic argument works for very simple arguments such as nid and uid
 */
class views_handler_argument extends views_handler {
  var $name_field = NULL;
  /**
   * Constructor
   */
  function construct() {
    if (!empty($this->definition['name field'])) {
      $this->name_field = $this->definition['name field'];
    }
  }

  /**
   * Give an argument the opportunity to modify the breadcrumb, if it wants.
   * This only gets called on displays where a breadcrumb is actually used.
   *
   * The breadcrumb will be in the form of an array, with the keys being
   * the path and the value being the already sanitized title of the path.
   */
  function set_breadcrumb(&$breadcrumb) { }

  /**
   * Provide defaults for the argument when a new one is created.
   */
  function options(&$options) {
    parent::options($options);
    $options['default_action'] = 'ignore';
    $options['style_plugin'] = 'default_summary';
    $options['style_options'] = array();
    $options['wildcard'] = 'all';
    $options['wildcard_substitution'] = t('All');
    $options['title'] = '';
  }

  /**
   * Provide a default options form for the argument.
   */
  function options_form(&$form, &$form_state) {
    $defaults = $this->default_actions();
    foreach ($defaults as $id => $info) {
      $options[$id] = $info['title'];
    }
    $form['default_action'] = array(
      '#prefix' => '<div class="views-left-50">',
      '#suffix' => '</div>',
      '#type' => 'radios',
      '#title' => t('Action to take if argument is not present'),
      '#options' => $options,
      '#default_value' => $this->options['default_action'],
    );
    $form['wildcard'] = array(
      '#prefix' => '<div class="views-left-40">',
      // prefix and no suffix means these two items will be grouped together.
      '#type' => 'textfield',
      '#title' => t('Wildcard'),
      '#size' => 20,
      '#default_value' => $this->options['wildcard'],
      '#description' => t('If this value is received as an argument, the argument will be ignored; i.e, "all values"'),
    );
    $form['wildcard_substitution'] = array(
      '#suffix' => '</div>',
      '#type' => 'textfield',
      '#title' => t('Wildcard title'),
      '#size' => 20,
      '#default_value' => $this->options['wildcard_substitution'],
      '#description' => t('The title to use for the wildcard in substitutions elsewhere.'),
    );
    $form['title'] = array(
      '#prefix' => '<div class="clear">',
      '#suffix' => '</div>',
      '#type' => 'textfield',
      '#title' => t('Title'),
      '#default_value' => $this->options['title'],
      '#description' => t('The title to use when this argument is present; it will override the title of the view and titles from previous arguments.'),
    );
  }

  /**
   * Provide a list of default behaviors for this argument if the argument
   * is not present.
   *
   * Override this method to provide additional (or fewer) default behaviors.
   */
  function default_actions($which = NULL) {
    $defaults = array(
      'ignore' => array(
        'title' => t('Display all values'),
        'method' => 'default_ignore',
        'breadcrumb' => TRUE, // generate a breadcrumb to here
      ),
      'not found' => array(
        'title' => t('Display page not found'),
        'method' => 'default_not_found',
      ),
      'empty' => array(
        'title' => t('Display empty text'),
        'method' => 'default_empty',
        'breadcrumb' => TRUE, // generate a breadcrumb to here
      ),
      'summary asc' => array(
        'title' => t('Summary, sorted ascending'),
        'method' => 'default_summary',
        'method args' => array('asc'),
        'style plugin' => TRUE,
        'breadcrumb' => TRUE, // generate a breadcrumb to here
      ),
      'summary desc' => array(
        'title' => t('Summary, sorted descending'),
        'method' => 'default_summary',
        'method args' => array('desc'),
        'style plugin' => TRUE,
        'breadcrumb' => TRUE, // generate a breadcrumb to here
      ),
    );

    if ($which) {
      if (!empty($defaults[$which])) {
        return $defaults[$which];
      }
    }
    else {
      return $defaults;
    }
  }

  /**
   * Determine if the can generate a breadcrumb
   *
   * @return TRUE/FALSE
   */
  function uses_breadcrumb() {
    $info = $this->default_actions($this->options['default_action']);
    return !empty($info['breadcrumb']);
  }

  /**
   * Determine if the argument needs a style plugin.
   *
   * @return TRUE/FALSE
   */
  function needs_style_plugin() {
    $info = $this->default_actions($this->options['default_action']);
    return !empty($info['style plugin']);
  }

  /**
   * Handle the default action, which means our argument wasn't present.
   *
   * Override this method only with extreme care.
   *
   * @return
   *   A boolean value; if TRUE, continue building this view. If FALSE,
   *   building the view will be aborted here.
   */
  function default_action() {
    $info = $this->default_actions($this->options['default_action']);
    if (!$info) {
      return FALSE;
    }

    if (!empty($info['method args'])) {
      return call_user_func_array(array($this, $info['method']), $info['method args']);
    }
    else {
      return $this->{$info['method']}();
    }
  }

  /**
   * Default action: ignore.
   *
   * If an argument was expected and was not given, in this case, simply
   * ignore the argument entirely.
   */
  function default_ignore() {
    return TRUE;
  }

  /**
   * Default action: not found.
   *
   * If an argument was expected and was not given, in this case, report
   * the view as 'not found' or hide it.
   */
  function default_not_found() {
    // Set a failure condition and let the display manager handle it.
    $this->view->build_info['fail'] = TRUE;
    return FALSE;
  }

  /**
   * Default action: empty
   *
   * If an argument was expected and was not given, in this case, display
   * the view's empty text
   */
  function default_empty() {
    // We return with no query; this will force the empty text.
    $this->view->built = TRUE;
    return FALSE;
  }

  /**
   * Default action: summary.
   *
   * If an argument was expected and was not given, in this case, display
   * a summary query.
   */
  function default_summary($order) {
    $this->view->build_info['summary'] = TRUE;
    $this->view->build_info['summary_level'] = $this->options['id'];

    // Change the display style to the summary style for this
    // argument.
    $this->view->style_plugin = $this->options['style_plugin'];
    $this->view->style_options = $this->options['style_options'];

    // Clear out the normal primary field and whatever else may have
    // been added and let the summary do the work.
    $this->query->clear_fields();
    $this->summary_query();

    $this->summary_sort($order);

    // Summaries have their own sorting and fields, so tell the View not
    // to build these.
    $this->view->build_sort = $this->view->build_fields = FALSE;
    return TRUE;
  }

  /**
   * Build the info for the summary query.
   *
   * This must:
   * - add_groupby: group on this field in order to create summaries.
   * - add_field: add a 'num_nodes' field for the count. Usually it will
   *   be a count on $view->primary_field
   * - set_count_field: Reset the count field so we get the right paging.
   *
   * @return
   *   The alias used to get the number of records (count) for this entry.
   */
  function summary_query() {
    $this->ensure_my_table();
    // Add the field.
    $this->base_alias = $this->query->add_field($this->table_alias, $this->real_field);

    // Add the 'name' field. For example, if this is a uid argument, the
    // name field would be 'name' (i.e, the username).
    if (isset($this->name_field)) {
      $this->name_alias = $this->query->add_field($this->table_alias, $this->name_field);
    }
    else {
      $this->name_alias = $this->base_alias;
    }

    return $this->summary_basics();
  }

  /**
   * Some basic summary behavior that doesn't need to be repeated as much as
   * code that goes into summary_query()
   */
  function summary_basics($count_field = TRUE) {
    // Add the number of nodes counter
    $count_alias = $this->query->add_field(NULL, 'COUNT('. $this->query->primary_table .'.'. $this->query->primary_field . ')', 'num_records');
    $this->query->add_groupby($this->base_alias);

    if ($count_field) {
      $this->query->set_count_field($this->table_alias, $this->real_field);
    }

    $this->count_alias = $count_alias;
  }

  /**
   * Sorts the summary based upon the user's selection. The base variant of
   * this is usually adequte.
   *
   * @param $order
   *   The order selected in the UI.
   */
  function summary_sort($order) {
    $this->query->add_orderby(NULL, NULL, $order, $this->base_alias);
  }

  /**
   * Provides a link from the summary to the next level; this will be called
   * once per row of a summary.
   *
   * @param $data
   *   The query results for the row.
   * @param $url
   *   The base URL to use.
   */
  function summary_link($data, $url) {
    $value = $data->{$this->base_alias};
    return url("$url/$value");
  }

  /**
   * Provides the name to use for the summary. By default this is just
   * the name field.
   *
   * @param $data
   *   The query results for the row.
   */
  function summary_name($data) {
    return check_plain($data->{$this->name_alias});
  }

  /**
   * Set up the query for this argument.
   *
   * The argument sent may be found at $this->argument.
   */
  function query() {
    $this->ensure_my_table();
    $this->query->add_where(0, "$this->table_alias.$this->real_field = '%s'", $this->argument);
  }

  /**
   * Get the title this argument will assign the view, given the argument.
   *
   * This usually needs to be overridden to provide a proper title.
   */
  function title() {
    return check_plain($this->argument);
  }

  /**
   * Validate that this argument works. By default, all arguments are valid.
   */
  function validate($arg) {
    return TRUE;
  }
}

/**
 * Abstract argument handler for simple formulae.
 *
 * Child classes of this object should implement summary_link, at least.
 */
class views_handler_argument_formula extends views_handler_argument {
  var $formula = NULL;
  /**
   * Constructor
   */
  function construct() {
    if (!empty($this->definition['formula'])) {
      $this->formula = $this->definition['formula'];
    }
  }

  /**
   * Build the summary query based on a formula
   */
  function summary_query() {
    $this->ensure_my_table();
    // Add the field.
    $this->base_alias = $this->name_alias = $this->query->add_field(NULL, $this->formula, $this->field);
    $this->query->set_count_field(NULL, $this->formula, $this->field);

    return $this->summary_basics(FALSE);
  }

  /**
   * Build the query based upon the formula
   */
  function query() {
    $this->ensure_my_table();
    $this->query->add_where(0, "$this->formula = '%s'", $this->argument);
  }
}

/**
 * @}
 */