<?php

/* Copyright (c) 1998-2011 ILIAS open source, Extended GPL, see docs/LICENSE */


/**
* Navigation History of Repository Items
*
* @author Alex Killing <alex.killing@gmx.de>
* @version $Id$
*/
class ilNavigationHistory
{
    /**
     * @var ilObjUser
     */
    protected $user;

    /**
     * @var ilDB
     */
    protected $db;

    /**
     * @var ilTree
     */
    protected $tree;

    /**
     * @var ilObjectDefinition
     */
    protected $obj_definition;

    /**
     * @var ilPluginAdmin
     */
    protected $plugin_admin;


    private $items;

    /**
    * Constructor.
    *
    * @param	int	$a_id
    */
    public function __construct()
    {
        global $DIC;

        $this->user = $DIC->user();
        $this->db = $DIC->database();
        $this->tree = $DIC->repositoryTree();
        $this->obj_definition = $DIC["objDefinition"];
        $this->plugin_admin = $DIC["ilPluginAdmin"];
        $this->items = array();
        $items = null;
        if (isset($_SESSION["il_nav_history"])) {
            $items = unserialize($_SESSION["il_nav_history"]);
        }
        if (is_array($items)) {
            $this->items = $items;
        }
    }

    /**
    * Add an item to the stack. If ref_id is already used,
    * the item is moved to the top.
    */
    public function addItem(
        $a_ref_id,
        $a_link,
        $a_type,
        $a_title = "",
        $a_sub_obj_id = "",
        $a_goto_link = ""
    ) {
        $ilUser = $this->user;
        $ilDB = $this->db;

        // never store?
        if ($ilUser->prefs["store_last_visited"] == 2) {
            return;
        }
        
        $a_sub_obj_id = $a_sub_obj_id . "";
        
        if ($a_title == "" && $a_ref_id > 0) {
            $obj_id = ilObject::_lookupObjId($a_ref_id);
            if (ilObject::_exists($obj_id)) {
                $a_title = ilObject::_lookupTitle($obj_id);
            }
        }

        $id = $a_ref_id . ":" . $a_sub_obj_id;

        $new_items[$id] = array("id" => $id,"ref_id" => $a_ref_id, "link" => $a_link, "title" => $a_title,
            "type" => $a_type, "sub_obj_id" => $a_sub_obj_id, "goto_link" => $a_goto_link);
        
        $cnt = 1;
        foreach ($this->items as $key => $item) {
            if ($item["id"] != $id && $cnt <= 10) {
                $new_items[$item["id"]] = $item;
                $cnt++;
            }
        }
        
        // put items in session
        $this->items = $new_items;

        $items = serialize($this->items);
        $_SESSION["il_nav_history"] = $items;
        //var_dump($this->getItems());


        // only store in session?
        if ($ilUser->prefs["store_last_visited"] == 1) {
            return;
        }


        // update entries in db
        $ilDB->update(
            "usr_data",
            array(
                    "last_visited" => array("clob", serialize($this->getItems()))),
            array(
                "usr_id" => array("integer", $ilUser->getId()))
        );
    }
    
    /**
    * Get navigation item stack.
    */
    public function getItems()
    {
        $tree = $this->tree;
        $ilDB = $this->db;
        $ilUser = $this->user;
        $objDefinition = $this->obj_definition;
        $ilPluginAdmin = $this->plugin_admin;
        
        $items = array();
        
        foreach ($this->items as $it) {
            if ($tree->isInTree($it["ref_id"]) &&
                (
                    !$objDefinition->isPluginTypeName($it["type"]) ||
                $ilPluginAdmin->isActive(
                    IL_COMP_SERVICE,
                    "Repository",
                    "robj",
                    ilPlugin::lookupNameForId(IL_COMP_SERVICE, "Repository", "robj", $it["type"])
                )
                )) {
                $items[$it["ref_id"] . ":" . $it["sub_obj_id"]] = $it;
            }
        }
        // less than 10? -> get items from db
        if (count($items) < 10 && $ilUser->getId() != ANONYMOUS_USER_ID) {
            $set = $ilDB->query(
                "SELECT last_visited FROM usr_data " .
                " WHERE usr_id = " . $ilDB->quote($ilUser->getId(), "integer")
            );
            $rec = $ilDB->fetchAssoc($set);
            $db_entries = unserialize($rec["last_visited"]);
            $cnt = count($items);
            if (is_array($db_entries)) {
                foreach ($db_entries as $rec) {
                    include_once("./Services/Link/classes/class.ilLink.php");
                    
                    if ($cnt <= 10 && !isset($items[$rec["ref_id"] . ":" . $rec["sub_obj_id"]])) {
                        if ($tree->isInTree($rec["ref_id"]) &&
                            (
                                !$objDefinition->isPluginTypeName($rec["type"]) ||
                            $ilPluginAdmin->isActive(
                                IL_COMP_SERVICE,
                                "Repository",
                                "robj",
                                ilPlugin::lookupNameForId(IL_COMP_SERVICE, "Repository", "robj", $rec["type"])
                            )
                            )) {
                            $link = ($rec["goto_link"] != "")
                                ? $rec["goto_link"]
                                : ilLink::_getLink($rec["ref_id"]);
                            if ($rec["sub_obj_id"] != "") {
                                $title = $rec["title"];
                            } else {
                                $title = ilObject::_lookupTitle(ilObject::_lookupObjId($rec["ref_id"]));
                            }
                            $items[$rec["ref_id"] . ":" . $rec["sub_obj_id"]] = array("id" => $rec["ref_id"] . ":" . $rec["sub_obj_id"],
                                "ref_id" => $rec["ref_id"], "link" => $link, "title" => $title,
                                "type" => $rec["type"], "sub_obj_id" => $rec["sub_obj_id"], "goto_link" => $rec["goto_link"]);
                            $cnt++;
                        }
                    }
                }
            }
        }
        //var_dump($items);
        return $items;
    }
    
    /**
     * Delete DB entries
     *
     * @param
     * @return
     */
    public function deleteDBEntries()
    {
        $ilUser = $this->user;
        $ilDB = $this->db;
        
        // update entries in db
        $ilDB->update(
            "usr_data",
            array(
                    "last_visited" => array("clob", serialize(array()))),
            array(
                "usr_id" => array("integer", $ilUser->getId()))
        );
    }

    /**
     * Delete session entries
     *
     * @param
     * @return
     */
    public function deleteSessionEntries()
    {
        $_SESSION["il_nav_history"] = serialize(array());
    }
}