<?php

/**
 * This class is responsible for displaying new clipboards
 * (the ones that use the Clipboard SORM class) in the sidebar.
 *
 * @author  Moritz Strohm <strohm@data-quest.de>
 * @license GNU General Public License v2 or later.
 * @since   4.5
 */
class ClipboardWidget extends SidebarWidget
{
    protected $allowed_item_class;
    protected $draggable_items;


    /**
     * clipboard_widget_id is required in the case that multiple
     * clipboard widgets exist on one page. The JavaScript code
     * can then distinguish each clipboard widget by its unique ID.
     */
    protected $clipboard_widget_id;


    /**
     * This attribute holds the ID of the clipboard which is stored in the
     * session as currently selected clipboard.
     */
    protected $current_clipboard_id;


    /**
     * This attribute contains a string that shall be the title of the button
     * for applying the selected clipbard to the main area
     * the widget is showing when in read only mode.
     */
    protected $apply_button_title;

    /**
     * This widget can be initialised with the class names of allowed classes
     * to limit the displayed items in a clipboard to items of specific
     * classes.
     */
    public function __construct($allowed_item_classes = [])
    {
        parent::__construct();

        if ($allowed_item_classes) {
            //Check if all allowed item classes are SimpleORMap objects
            //and if the classes implement the StudipItem interface:
            foreach ($allowed_item_classes as $class) {
                if (!is_subclass_of($class, 'StudipItem', true)) {
                    throw new InvalidArgumentException(
                        sprintf(
                            'The class %s does not implement the StudipItem interface which is required for clipboard items!',
                            htmlReady($class)
                        )
                    );
                }
            }
        } else {
            //Allow all StudipItem implementations:
            $allowed_item_classes = ['StudipItem'];
        }

        $this->allowed_item_classes = $allowed_item_classes;
        $this->template = 'sidebar/clipboard-widget';
        $this->title = _('Merkzettel');
        $this->readonly = false;
        $this->apply_button_title = _('Hauptbereich aktualisieren');

        $this->clipboard_widget_id = md5(uniqid('clipboard_widget_id'));
        $this->draggable_items = false;

        $this->updateSessionVariables();
        $this->current_clipboard_id = $_SESSION['selected_clipboard_id'];
        $this->current_selected_items = $_SESSION['selected_clipboard_items'];
        if (!is_array($this->current_selected_items)) {
            $this->current_selected_items = [];
        }
    }


    public function clearSessionVariables()
    {
        $_SESSION['selected_clipboard_id'] = null;
        $_SESSION['selected_clipboard_items'] = [];
    }


    /**
     * Updates session variables if a special POST request is made.
     */
    public function updateSessionVariables()
    {
        if (Request::submitted('clipboard_update_session_special_action')) {
            CSRFProtection::verifyUnsafeRequest();

            $_SESSION['selected_clipboard_id'] = Request::get(
                'selected_clipboard_id'
            );
            $_SESSION['selected_clipboard_items'] = Request::getArray(
                'selected_clipboard_items'
            );
        }
    }


    /**
     * Enables clipboard items to be dragged to the main area of the page.
     */
    public function enableDraggableItems()
    {
        $this->draggable_items = true;
    }


    /**
     * Disables the dragging of clipboard items.
     */
    public function disableDraggableItems()
    {
        $this->draggable_items = false;
    }


    public function setReadonly($readonly = false)
    {
        $this->readonly = (bool)$readonly;
    }


    public function isReadonly()
    {
        return $this->readonly;
    }


    public function setApplyButtonTitle($title = '')
    {
        if ($title) {
            $this->apply_button_title = $title;
        }
    }


    public function getApplyButtonTitle()
    {
        return $this->apply_button_title;
    }


    public function getClipboardWidgetId()
    {
        return $this->clipboard_widget_id;
    }


    public function render($variables = [])
    {
        $template = $GLOBALS['template_factory']->open(
            $this->template
        );

        $layout = $GLOBALS['template_factory']->open(
            'widgets/widget-layout'
        );
        $template->set_layout('widgets/widget-layout');

        $clipboards = Clipboard::getClipboardsForUser(
            $GLOBALS['user']->id
        );

        if (!$this->current_clipboard_id) {
            if ($clipboards) {
                $_SESSION['selected_clipboard_id'] = $clipboards[0]->id;
                $_SESSION['selected_clipboard_items'] = [];
                $this->current_clipboard_id = $clipboards[0]->id;
            }
        }

        $template->set_attribute(
            'selected_clipboard_id',
            $this->current_clipboard_id
        );
        $template->set_attribute(
            'selected_clipboard_items',
            $this->current_selected_items
        );
        $template->set_attribute('clipboards', $clipboards);
        $template->set_attribute(
            'allowed_item_classes',
            $this->allowed_item_classes
        );
        $template->set_attribute(
            'clipboard_widget_id',
            $this->clipboard_widget_id
        );
        $template->set_attribute(
            'draggable_items',
            $this->draggable_items
        );
        $template->set_attribute(
            'readonly',
            $this->readonly
        );
        $template->set_attribute(
            'apply_button_title',
            $this->apply_button_title
        );
        $template->set_attribute(
            'elements',
            $this->elements
        );

        return $template->render();
    }

    /**
     * Adds a link to the widget
     *
     * @param String $label  Label/content of the link
     * @param String $url    URL/Location of the link
     * @param Icon   $icon   instance of class Icon for the link
     * @param bool   $active Pass true if the link is currently active,
     *                       defaults to false
     */
    public function &addLink($label, $url, $icon = null, $attributes = array(), $index = null)
    {
        if ($index === null) {
            $index = 'link-' . md5($url);
        }
        $element = new LinkElement($label, $url, $icon, $attributes);
        $this->addElement($element, $index);
        return $element;
    }
}