class views_handler_sort

class views_handler_sort extends views_handler {
    
    /**
     * Determine if a sort can be exposed.
     */
    function can_expose() {
        return TRUE;
    }
    
    /**
     * 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']);
    }
    function option_definition() {
        $options = parent::option_definition();
        $options['order'] = array(
            'default' => 'ASC',
        );
        $options['exposed'] = array(
            'default' => FALSE,
        );
        $options['expose'] = array(
            'contains' => array(
                'label' => array(
                    'default' => '',
                    'translatable' => TRUE,
                ),
            ),
        );
        return $options;
    }
    
    /**
     * Display whether or not the sort order is ascending or descending
     */
    function admin_summary() {
        if (!empty($this->options['exposed'])) {
            return t('Exposed');
        }
        switch ($this->options['order']) {
            case 'ASC':
            case 'asc':
            default:
                return t('asc');
                break;
            case 'DESC':
            case 'desc':
                return t('desc');
                break;
        }
    }
    
    /**
     * Basic options for all sort criteria
     */
    function options_form(&$form, &$form_state) {
        parent::options_form($form, $form_state);
        if ($this->can_expose()) {
            $this->show_expose_button($form, $form_state);
        }
        $form['op_val_start'] = array(
            '#value' => '<div class="clear-block">',
        );
        $this->show_sort_form($form, $form_state);
        $form['op_val_end'] = array(
            '#value' => '</div>',
        );
        if ($this->can_expose()) {
            $this->show_expose_form($form, $form_state);
        }
    }
    
    /**
     * Simple validate handler
     */
    function options_validate(&$form, &$form_state) {
        $this->sort_validate($form, $form_state);
        if (!empty($this->options['exposed'])) {
            $this->expose_validate($form, $form_state);
        }
    }
    
    /**
     * Simple submit handler
     */
    function options_submit(&$form, &$form_state) {
        unset($form_state['values']['expose_button']);
        // don't store this.
        $this->sort_submit($form, $form_state);
        if (!empty($this->options['exposed'])) {
            $this->expose_submit($form, $form_state);
        }
    }
    
    /**
     * Shortcut to display the value form.
     */
    function show_sort_form(&$form, &$form_state) {
        $options = $this->sort_options();
        if (!empty($options)) {
            $form['order'] = array(
                '#type' => 'radios',
                '#options' => $options,
                '#default_value' => $this->options['order'],
            );
        }
    }
    function sort_validate(&$form, &$form_state) {
    }
    function sort_submit(&$form, &$form_state) {
    }
    
    /**
     * Provide a list of options for the default sort form.
     * Should be overridden by classes that don't override sort_form
     */
    function sort_options() {
        return array(
            'ASC' => t('Sort ascending'),
            'DESC' => t('Sort descending'),
        );
    }
    
    /**
     * Since all exposed sorts are grouped into one select box.
     * We don't return nothing when views call to exposed_form()
     */
    function exposed_form(&$form, &$form_state) {
    }
    
    /**
     * Handle the 'left' side fo the exposed options form.
     */
    function expose_form_left(&$form, &$form_state) {
        $form['expose']['label'] = array(
            '#type' => 'textfield',
            '#default_value' => $this->options['expose']['label'],
            '#title' => t('Label'),
            '#required' => TRUE,
            '#size' => 40,
        );
    }
    
    /**
     * Handle the 'right' side fo the exposed options form.
     */
    function expose_form_right(&$form, &$form_state) {
        $form['expose']['order'] = array(
            '#type' => 'value',
            '#value' => 'ASC',
        );
    }
    
    /**
     * Provide default options for exposed sorts.
     */
    function expose_options() {
        $this->options['expose'] = array(
            'order' => $this->options['order'],
            'label' => $this->ui_name(),
        );
    }

}