# The LearningOnline Network with CAPA
# Routines to control the wishlist
#
# $Id: lonwishlist.pm,v 1.1 2010/08/10 14:30:20 wenzelju Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#



package Apache::lonwishlist;

use strict;
use Apache::Constants qw(:common);
use Apache::lonnet;
use Apache::loncommon();
use Apache::lonhtmlcommon;
use Apache::lonlocal;
use Tree;


# Global variables
my $root;
my @childrenRt;
my %TreeHash;
my %TreeToHash;
my @allFolders;
my @allNodes;
my $indentConst = 20;


# Read wishlist from user-data
sub getWishlist {
    my @wishlistkeys = &Apache::lonnet::getkeys('wishlist');
    my %wishlist = &Apache::lonnet::get('wishlist',\@wishlistkeys);
   foreach my $i (%wishlist) {
        #File not found. This appears at the first time using the wishlist
        #Create file and put 'root' into it
       if ($i =~m/^error:No such file/) {
           &Apache::lonnet::logthis($i.'! Create file by putting in the "root" of the directory tree.');
           &Apache::lonnet::put('wishlist', {'root' => ''});
           @wishlistkeys = &Apache::lonnet::getkeys('wishlist');
           %wishlist = &Apache::lonnet::get('wishlist',\@wishlistkeys);
       }
       elsif ($i =~ /^(con_lost|error|no_such_host)/i) {
           &Apache::lonnet::logthis('ERROR while attempting to get wishlist: '.$i);
           return 'error';
       }
    }

    #If hash is empty, put 'root' into it, so we got a node to start the tree
    if ((keys %wishlist) == 0) {
        &Apache::lonnet::logthis('ERROR while attempting to get wishlist: no keys retrieved!');
        return 'error';
    }
    
    return %wishlist;
}


# Write wishlist to user-data
sub putWishlist {
    my $wishlist = shift;
    &Apache::lonnet::put('wishlist',$wishlist);
}


# Removes all existing entrys for wishlist in user-data
sub deleteWishlist {
    my @wishlistkeys = &Apache::lonnet::getkeys('wishlist');
    my %wishlist = &Apache::lonnet::del('wishlist',\@wishlistkeys);
}


# Create a new entry
sub newEntry() {
    my ($title, $path, $note) = @_;
    my $date = gmtime();
    # Create Entry-Object
    my $entry = Entry->new(title => $title, path => $path, note => $note, date => $date);
    # Create Tree-Object, this correspones a node in the wishlist-tree
    my $tree = Tree->new($entry);
    # Add this node to wishlist-tree
    my $folderIndex = $env{'form.folders'};
    if ($folderIndex ne '') {
        @allFolders = ();
        &getFoldersToArray(\@childrenRt);
        my $folderToInsertOn = &Tree::getNodeByIndex($folderIndex,\@allFolders);
        $folderToInsertOn->add_child($tree);
    }
    else {
        $root->add_child($tree);
    }
    &saveChanges();
}


# Delete entries
sub deleteEntries {
    my $marked = shift;
    &getNodesToArray(\@childrenRt);

    foreach my $m (@$marked) {
        my $found = &Tree::getNodeByIndex($m, \@allNodes);
        &Tree::removeNode($found);
    }
    @allNodes = ();
    &saveChanges();
}


# Sort entries
sub sortEntries {
    my $indexNode = shift;
    my $at = shift;
    
    &getNodesToArray(\@childrenRt);
    my $foundNode = &Tree::getNodeByIndex($indexNode, \@allNodes);

    &Tree::moveNode($foundNode,$at,undef);
    @allNodes = ();
}


# Move entries
sub moveEntries {
    my $indexNodesToMove = shift;
    my $indexParent = shift;
    my @nodesToMove = ();

    &getNodesToArray(\@childrenRt);
    foreach my $index (@$indexNodesToMove) {
        my $foundNode = &Tree::getNodeByIndex($index, \@allNodes);
        push(@nodesToMove, $foundNode);
    }

    foreach my $node (@nodesToMove) {
        my $foundParent;
        my $parentIsIn = 0;
        foreach my $n (@nodesToMove) {
            if ($node->parent()->value() ne "root") {
               if ($node->parent()->value()->nindex() == $n->value()->nindex()) {
                    $parentIsIn = 1;
                }
            }
        }
        if (!$parentIsIn) {
            if ($indexParent ne "root") {
                $foundParent = &Tree::getNodeByIndex($indexParent, \@allNodes);
                &Tree::moveNode($node,undef,$foundParent);
            }
            else {
                &Tree::moveNode($node,undef,$root);
            }
        }
    }
    @allNodes = ();
}


# Set a new title for an entry
sub setNewTitle {
    my ($nodeindex, $newTitle) = @_;
    &getNodesToArray(\@childrenRt);
    my $found = &Tree::getNodeByIndex($nodeindex, \@allNodes);
    $found->value()->title($newTitle); 
    @allNodes = ();
}


# Set a new note for an entry
sub setNewNote {
    my ($nodeindex, $newNote) = @_;
    &getNodesToArray(\@childrenRt);
    my $found = &Tree::getNodeByIndex($nodeindex, \@allNodes);
    $found->value()->note($newNote); 
    @allNodes = ();
}


# Save all changes
sub saveChanges {
    @childrenRt = $root->children();
    &Tree::TreeIndex(\@childrenRt);
    &Tree::setCountZero();
    &Tree::RootToHash(\@childrenRt);
    &Tree::TreeToHash(\@childrenRt);
    &deleteWishlist();
    &putWishlist(\%TreeToHash);

}


# Return the names for all exiting folders in option-tags, so
# a new link or a new folder can be created in an existing folder
my $indent = 0;
my $foldersOption;
sub getFoldersForOption {
    my $nodes = shift;

    foreach my $n (@$nodes) {
        if ($n->value()->path() eq '') {
            $foldersOption .= '<option value="'.$n->value()->nindex().'" style="margin-left:'.$indent.'px">'.
                                   $n->value()->title().
                               '</option>';

        my @children = $n->children();
        if ($#children >=0) {
            $indent += 10;
            &getFoldersForOption(\@children);
            $indent -= 10;
            }
        }
    }
}


sub getfoldersOption {
   if (&getWishlist ne 'error') {
       %TreeHash = &getWishlist();
       $root = &Tree::HashToTree();
       @childrenRt = $root->children();
       &getFoldersForOption(\@childrenRt);
       my $options = '<option value="" selected="selected"></option>'.$foldersOption;
       $foldersOption = '';
       return $options;
   }
   else {
       return '';
   }
}


# Put all folder-nodes to an array
sub getFoldersToArray {
    my $children = shift;
    foreach my $c (@$children) {
        if ($c->value()->path() eq '') {
            push(@allFolders,$c);
        }
        my @newchildren = $c->children();
        if ($#newchildren >= 0) {
            &getFoldersToArray(\@newchildren);
        }
    }
}


# Put all nodes to an array
sub getNodesToArray {
    my $children = shift;
    foreach my $c (@$children) {
        push(@allNodes,$c);
        my @newchildren = $c->children();
        if ($#newchildren >= 0) {
            &getNodesToArray(\@newchildren);
        }
    }
}


# Return a script-tag containing Javascript-function
# needed for wishlist actions like 'new link' ect.
sub JSforWishlist {
    my $startPagePopup = &Apache::loncommon::start_page('Wishlist',undef,
                                                            {'only_body' => 1,
                                                             'js_ready'  => 1,
                                                             'bgcolor'   => '#FFFFFF',});
    my $endPagePopup = &Apache::loncommon::end_page({'js_ready' => 1});

    @allFolders = ();
    &getFoldersToArray(\@childrenRt);
    &getFoldersForOption(\@childrenRt);

    # texthash
    my %lt = &Apache::lonlocal::texthash(
                 'nl' => 'New Link',
                 'nf' => 'New Folder',
                 'lt' => 'Link Title',
                 'ft' => 'Folder Title',
                 'pa' => 'Path',
                 'nt' => 'Note',
                 'si' => 'Save in',
                 'cl' => 'Cancel');


    my $inPageNewLink = '<h1>'.$lt{'nl'}.'</h1>'.
                        '<form method="post" name="newlink" action="/adm/wishlist" target="wishlist" '.
                        'onsubmit="return newlinksubmit();" >'.
                        &Apache::lonhtmlcommon::start_pick_box().
                        &Apache::lonhtmlcommon::row_title($lt{'lt'}).
                        '<input type="text" name="title" size="45" value="" />'.
                        &Apache::lonhtmlcommon::row_closure().
                        &Apache::lonhtmlcommon::row_title($lt{'pa'}).
                        '<input type="text" name="path" size="45" value="" />'.
                        &Apache::lonhtmlcommon::row_closure().
                        &Apache::lonhtmlcommon::row_title($lt{'nt'}).
                        '<textarea name="note" rows="3" cols="35" style="width:100%"></textarea>'.
                        &Apache::lonhtmlcommon::row_closure(1).
                        &Apache::lonhtmlcommon::end_pick_box().
                        '<br/><br/>'.
                        '<input type="submit" value="'.$lt{'si'}.'" />'.
                        '<select name="folders">'.
                        '<option value="" selected="selected"></option>'.
                        $foldersOption.
                        '</select>'.
                        '<input type="button" value="'.$lt{'cl'}.'" onclick="javascript:window.close();" />'.
                        '</form>';
    
    my $inPageNewFolder = '<h1>'.$lt{'nf'}.'</h1>'.
                          '<form method="post" name="newfolder" action="/adm/wishlist" target="wishlist" '.
                          'onsubmit="return newfoldersubmit();" >'.
                          &Apache::lonhtmlcommon::start_pick_box().
                          &Apache::lonhtmlcommon::row_title($lt{'ft'}).
                          '<input type="text" name="title" size="45" value="" /><br />'.
                          &Apache::lonhtmlcommon::row_closure().
                          &Apache::lonhtmlcommon::row_title($lt{'nt'}).
                          '<textarea name="note" rows="3" cols="35" style="width:100%"></textarea><br />'.
                          &Apache::lonhtmlcommon::row_closure(1).
                          &Apache::lonhtmlcommon::end_pick_box().
                          '<br/><br/>'.
                          '<input type="submit" value="'.$lt{'si'}.'" />'.
                          '<select name="folders">'.
                          '<option value="" selected="selected"></option>'.
                          $foldersOption.
                          '</select>'.
                          '<input type="button" value="'.$lt{'cl'}.'" onclick="javascript:window.close();" />'.
                          '</form>';

    # Remove all \n for inserting on javascript document.write
    $inPageNewLink =~ s/\n//g;
    $inPageNewFolder =~ s/\n//g;

    my $warningLink = &mt('You must insert a title and a path!');
    my $warningFolder = &mt('You must insert a title!');
    my $warningDelete = &mt('Are you sure you want to delete the selected entries? Deleting a folder also deletes all entries within this folder!');
    my $warningSave = &mt('You have unsaved changes. You can either save these changes now by clicking "ok" or click "cancel" if you do not want to save your changes.');
    my $warningMove = &mt('You must select a destination folder!');
    $foldersOption = '';

    my $js = &Apache::lonhtmlcommon::scripttag(<<JAVASCRIPT);
    function newLink() {
        newlinkWin=window.open('','newlinkWin','width=580,height=320,scrollbars=yes');
        newlinkWin.document.write('$startPagePopup' 
                              +'<script type="text\/javascript">'
                              +'function newlinksubmit(){'
                              +'var path = document.getElementsByName("path")[0].value;'
                              +'var title = document.getElementsByName("title")[0].value;'
                              +'if (!path || !title) {'
                              +'alert("$warningLink");'
                              +'return false;}'
                              +'else {'
                              +'window.close();'
                              +'return true;}}'
                              +'<\/scr'+'ipt>'
                              +'$inPageNewLink'
                              +'$endPagePopup');
        newlinkWin.document.close();
    }

    function newFolder() {
        newfolderWin=window.open('','newfolderWin','width=580,height=270, scrollbars=yes');
        newfolderWin.document.write('$startPagePopup' 
                              +'<script type="text\/javascript">'
                              +'function newfoldersubmit(){'
                              +'var title = document.getElementsByName("title")[0].value;'
                              +'if (!title) {'
                              +'alert("$warningFolder");'
                              +'return false;}'
                              +'else {'
                              +'window.close();'
                              +'return true;}}'
                              +'<\/scr'+'ipt>'
                              +'$inPageNewFolder'
                              +'$endPagePopup');
        newfolderWin.document.close();
    }

    function setFormAction(action,mode) {
        var r = true;
        setAction('');
        if (action == 'delete') {
            r = confirm("$warningDelete");
            setAction('delete');
        }
        else if (action == 'save') {
            var d = getDifferences();
            if (d) {
                if (!confirm('$warningSave')) {
                    setAction('noSave');
                }
            }
            r = true;
        }
        document.getElementsByName('list')[0].setAttribute("action", "/adm/wishlist?mode="+mode); 
        if(r){
            document.getElementsByName('list')[0].submit(); 
        }
    }

    function setAction(action) {
        document.getElementById('action').value = action; 
    }

    function getDifferences() {
        var newtitles = document.getElementsByName('newtitle');
        var i = 0;
        for (i=0;i<newtitles.length;i++) {
            var newt = newtitles[i].value;
            var oldt = newtitles[i].alt;
            if (newt != oldt) {
                return true;
            }
        }
        var newnote = document.getElementsByName('newnote');
        var i = 0;
        for (i=0;i<newnote.length;i++) {
            var newn = newnote[i].value;
            var oldn = newnote[i].innerHTML;
            if (newn != oldn) {
                return true;
            }
        }
        return false;
    }

    function onLoadAction(mode) {
        window.name = 'wishlist';
        if (mode == "edit") {
            var deepestRows = getDeepestRows();
            setDisplaySelect(deepestRows, '');
        }
    }

    function folderAction(rowid) {
        var row = document.getElementById(rowid);
        var indent = getIndent(row);
        var displ;
        var status;
        if (getImage(row) == 'closed') {
            displ = '';
            status = 'open';
        }
        else {
            displ = 'LC_hidden';
            status = 'closed';
        }
        setImage(row,status);
        if (getNextRow(row) != null) {
            var nextIndent = getIndent(getNextRow(row));
            row = getNextRow(row);
            while (nextIndent > indent) {
                if (displ == '') {
                    row.className = (row.className).replace('LC_hidden','');
                }
                else if (displ != '' && !((row.className).match('LC_hidden'))) {
                    var oldClass = row.className;
                    row.className = oldClass+' LC_hidden';
                    setDisplayNote(row.id.replace('row','note'),'LC_hidden');
                }
                if (status == 'open' && getImage(row).match('closed')) {
                    row = getNextRowWithIndent(row, getIndent(row));
                }
                else {
                    row = getNextRow(row);
                } 
                if (row != null) {
                    nextIndent = getIndent(row);
                } 
                else {
                    nextIndent = indent;
                }
            }
        }
        setClasses();
        var newtitles = document.getElementsByName('newtitle');
        if (newtitles.length>0) {
            var deepestRows = getDeepestRows();
            var otherRows = getOtherRows(deepestRows);
            setDisplaySelect(deepestRows,'');
            setDisplaySelect(otherRows,'LC_hidden');
        }
    }

    function selectAction(rowid) {
        var row = document.getElementById(rowid);
        var indent = getIndent(row);
        var checked = getChecked(row);
        var previousFolderRows = new Array();
        if (indent != 0) {
            previousFolderRows = getPreviousFolderRows(row);
        }
        if (getNextRow(row) != null) {
            var nextIndent = getIndent(getNextRow(row));
            row = getNextRow(row);
                while (nextIndent > indent) {
                    setChecked(row,checked);
                    if (status == 'open' && getImage(row).match('closed')) {
                        row = getNextRowWithIndent(row, getIndent(row));
                    }
                    else {
                        row = getNextRow(row);
                    }
                    if (row != null) {
                        nextIndent = getIndent(row);
                    }
                    else {
                        nextIndent = indent;
                    }
                }
        }
        if (!checked) {
            var i = 0;
            for (i=0;i<previousFolderRows.length;i++) {
                setChecked(previousFolderRows[i], false);
            }
        }
    }

    function getNextNote(row) {
        var rowId = row.id;
        var nextRowId = parseInt(rowId.substr(3,rowId.length))+1;
        nextRowId = "note"+nextRowId;
        var nextRow = document.getElementById(nextRowId);
        return nextRow;
    }

    function getNextRow(row) {
        var rowId = row.id;
        var nextRowId = parseInt(rowId.substr(3,rowId.length))+1;
        nextRowId = "row"+nextRowId;
        var nextRow = document.getElementById(nextRowId);
        return nextRow;
    }

    function getPreviousRow(row) {
        var rowId = row.id;
        var previousRowId =  parseInt(rowId.substr(3,rowId.length))-1;
        previousRowId = "row"+previousRowId;
        var previousRow =document.getElementById(previousRowId);
        return previousRow;
    }

    function getIndent(row) {
        var childPADD = document.getElementById(row.id.replace('row','padd'));
        indent = childPADD.style.paddingLeft;
        indent = parseInt(indent.substr(0,(indent.length-2)));
 
        if (getImage(row).match('link')) {
            indent -= $indentConst;
        }
        return indent;
    }

    function getNextRowWithIndent(row, indent) {
        var nextRow = getNextRow(row);
        if (nextRow != null) {
        var nextIndent = getIndent(nextRow);
        while (nextIndent >= indent) {
            if (nextIndent == indent) {
                return nextRow;
            }
            nextRow = getNextRow(nextRow);
            if (nextRow == null) {
                return null;
            }
            nextIndent = getIndent(nextRow);
        }
        }
        return nextRow;
    }

    function getImage(row) {
        var childIMG = document.getElementById(row.id.replace('row','img'));
        if ((childIMG.src).match('closed')) {
            return 'closed';
        }
        else if ((childIMG.src).match('open')) {
            return 'open;'
        }
        else {
            return 'link';
        }
    } 

    function setImage(row, status) {
        var childIMG = document.getElementById(row.id.replace('row','img'));
        var childIMGFolder = document.getElementById(row.id.replace('row','imgFolder'));
        childIMG.src = "/adm/lonIcons/arrow."+status+".gif";
        childIMGFolder.src="/adm/lonIcons/navmap.folder."+status+".gif"; 
    }

    function getChecked(row) {
        var childCHECK = document.getElementById(row.id.replace('row','check'));
        var checked = childCHECK.checked;
        return checked;
    }

    function setChecked(row,checked) {
        var childCHECK = document.getElementById(row.id.replace('row','check'));
        childCHECK.checked = checked;
    }

    function getPreviousFolderRows(row) {
        var previousRow = getPreviousRow(row);
        var indent = getIndent(previousRow);
        var kindOfEntry = getImage(previousRow);
        var rows = new Array();
        if (kindOfEntry != 'link') {
            rows.push(previousRow);
        }

        while (indent >0) {
            previousRow = getPreviousRow(previousRow);
            if (previousRow != null) {
                indent = getIndent(previousRow);
                kindOfEntry = getImage(previousRow);
                if (kindOfEntry != 'link') {
                    rows.push(previousRow);
                }
            }
            else {
                indent = 0; 
            }
        }
        return rows;
    }

    function getDeepestRows() {
        var row = document.getElementById('row0');
        var firstRow = row;
        var indent = getIndent(row);
        var maxIndent = indent;
        while (getNextRow(row) != null) {
            row = getNextRow(row);
            indent = getIndent(row);
            if (indent>maxIndent && !((row.className).match('LC_hidden'))) {
                maxIndent = indent;
            }
        }
        var deepestRows = new Array();
        row = firstRow;
        var rowIndent;
        while (getNextRow(row) != null) {
            rowIndent = getIndent(row);
            if (rowIndent == maxIndent) {
                deepestRows.push(row);
            }
            row = getNextRow(row);
        }
        rowIndent = getIndent(row);
        if (rowIndent == maxIndent) {
            deepestRows.push(row);
        }
        return deepestRows;
    }

    function getOtherRows(deepestRows) {
        var row = document.getElementById('row0');
        var otherRows = new Array();
        var isIn = false;
        while (getNextRow(row) != null) {
            var i = 0;
            for (i=0; i < deepestRows.length; i++) {
                if (row.id == deepestRows[i].id) {
                    isIn = true;
                }
            }
            if (!isIn) {
                otherRows.push(row);
            }
            row = getNextRow(row);
            isIn = false;
        }
        for (i=0; i < deepestRows.length; i++) {
            if (row.id == deepestRows[i].id) {
                isIn = true;
            }
        }
        if (!isIn) {
            otherRows.push(row);
        }
        return otherRows;
    }

    function setDisplaySelect(deepestRows, displ) {
        var i = 0;
        for (i = 0; i < deepestRows.length; i++) {
            var row = deepestRows[i];
            var childSEL = document.getElementById(row.id.replace('row','sel'));
            childSEL.className = displ;
        } 
    }

    function submitSelect() {
       var list = document.getElementsByName('list')[0];
       list.setAttribute("action","/adm/wishlist?mode=edit");
       list.submit();
    }

    function setDisplayNote(rowid, displ) {
        var row = document.getElementById(rowid);
        if (!displ) {
            if ((row.className).match('LC_hidden')) {
                row.className = (row.className).replace('LC_hidden','');
            }
            else {
                var oldClass = row.className;
                row.className = oldClass+' LC_hidden';
            }
        }
        else {
            if (displ == '') {
                row.className = (row.className).replace('LC_hidden','');
            }
            else if (displ != '' && !((row.className).match('LC_hidden'))) {
                var oldClass = row.className;
                row.className = oldClass+' LC_hidden';
            }
        }
        var noteText = document.getElementById(rowid.replace('note','noteText'));
        var noteImg = document.getElementById(rowid.replace('note','noteImg'));
        if (noteText.value) {
            noteImg.src = "/res/adm/pages/anot2.png";
        }
        else {
            noteImg.src = "/res/adm/pages/anot.png";
        }

    }

    function setClasses() {
        var row = document.getElementById("row0");
        var note = document.getElementById("note0");
        var LC_class = 0;
        if (getNextRow(row) != null) {
            while (getNextRow(row) != null) {
                if (!(row.className).match('LC_hidden')) {
                    note.className = (note.className).replace('LC_even_row','');
                    note.className = (note.className).replace('LC_odd_row','');
                    if (LC_class) {
                        row.className = 'LC_even_row';
                        note.className = 'LC_even_row'+note.className;
                    }
                    else {
                        row.className = 'LC_odd_row';
                        note.className = 'LC_odd_row'+note.className;;
                    }
                    LC_class = !LC_class;
                }
                note = getNextNote(row);
                row = getNextRow(row);
            }
        }
        if (!(row.className).match('LC_hidden')) {
            note.className = (note.className).replace('LC_even_row','');
            note.className = (note.className).replace('LC_odd_row','');
            if (LC_class) {
                row.className = 'LC_even_row';
                note.className = 'LC_even_row'+note.className;
            }
            else {
                row.className = 'LC_odd_row';
                note.className = 'LC_odd_row'+note.className;
            }
        }
    }

    function selectDestinationFolder() {
        var mark = document.getElementsByName('mark');
        var i = 0;
        for (i = 0; i < mark.length; i++) {
            if (mark[i].checked) {
                document.getElementsByName('list')[0].submit();
                return true;
            }
        }
        alert('$warningMove');
        return false;
    }

JAVASCRIPT
   return $js;
}


# HTML-Markup for table if in view-mode
my $wishlistHTMLview;
my $indent = $indentConst;
sub wishlistView {
    my $nodes = shift;

    foreach my $n (@$nodes) {
        my $index = $n->value()->nindex();

        # start row, use data_table routines to set class to LC_even or LC_odd automatically. this row contains a checkbox, the title and the note-icon.
        # only display the top level entries on load
        $wishlistHTMLview .= ($n->parent()->value() eq 'root')?&Apache::loncommon::start_data_table_row('','row'.$index)
                                                              :&Apache::loncommon::continue_data_table_row('LC_hidden','row'.$index);

 
        # checkboxes
        $wishlistHTMLview .= '<td><input type="checkbox" name="mark" id="check'.$index.'" value="'.$index.'" '.
                             'onclick="selectAction('."'row".$index."'".')"/></td>';

        # entry is a folder
        if ($n->value()->path() eq '') {
            $wishlistHTMLview .= '<td id="padd'.$index.'" style="padding-left:'.(($indent-$indentConst)<0?0:($indent-$indentConst)).'px; min-width: 220px;">'.
                                 '<a href="javascript:;" onclick="folderAction('."'row".$index."'".')" style="vertical-align:top">'.
                                 '<img src="/adm/lonIcons/arrow.closed.gif" id="img'.$index.'" alt = "" class="LC_icon"/>'.
                                 '<img src="/adm/lonIcons/navmap.folder.closed.gif" id="imgFolder'.$index.'" alt="folder"/>'.
                                 $n->value()->title().'</a></td>';
        }
        # entry is a link
        else {
            $wishlistHTMLview .= '<td id="padd'.$index.'" style="padding-left:'.(($indent-$indentConst)<=0?$indentConst:$indent).'px; min-width: 220px;">'.
                                 '<img src="/res/adm/pages/wishlist-link.png" id="img'.$index.'" alt="link" />'.
                                 '<a href="'.$n->value()->path().'">'.$n->value()->title().'</a></td>';
        }

        # note-icon, different icons for an entries with note and those without
        my $noteIMG = 'anot.png';

        if ($n->value()->note() ne '') {
            $noteIMG = 'anot2.png';
        }

        $wishlistHTMLview .= '<td style="padding-left:10px;"><a href="javascript:;" onclick="setDisplayNote('."'note".$index."'".')">'.
                             '<img id="noteImg'.$index.'" src="/res/adm/pages/'.$noteIMG.'" alt="'.&mt('Note').'" title="'.&mt('Note').'" '.
                             ' class="LC_icon"/></a></td>';

        $wishlistHTMLview .= &Apache::loncommon::end_data_table_row();

        # start row containing the textarea for the note, do not display note on default
        $wishlistHTMLview .= &Apache::loncommon::continue_data_table_row('LC_hidden','note'.$index).
                             '<td></td><td>'.
                             '<textarea id="noteText'.$index.'" cols="25" rows="3" style="width:100%" '.
                             'name="newnote" >'.
                             $n->value()->note().'</textarea></td><td></td>';
        $wishlistHTMLview .= &Apache::loncommon::end_data_table_row();

        # if the entry is a folder, it could have other entries as content. if it has, call wishlistView for those entries 
        my @children = $n->children();
        if ($#children >=0) {
            $indent += 20;
            &wishlistView(\@children);
            $indent -= 20;
        }
    }
}


# HTML-Markup for table if in edit-mode
my $wishlistHTMLedit;
my $indent = $indentConst;
sub wishlistEdit {
    my $nodes = shift;
    my $curNode = 1;

    foreach my $n (@$nodes) {
        my $index = $n->value()->nindex();

        # start row, use data_table routines to set class to LC_even or LC_odd automatically.
        # this rows contains a checkbox, a select-field for sorting entries, the title in an input-field and the note-icon.
        # only display the top level entries on load
        $wishlistHTMLedit .= ($n->parent()->value() eq 'root')?&Apache::loncommon::start_data_table_row('','row'.$index)
                                                              :&Apache::loncommon::continue_data_table_row('LC_hidden','row'.$index);

        # checkboxes
        $wishlistHTMLedit .= '<td><input type="checkbox" name="mark" id="check'.$index.'" value="'.$index.'" '.
                             'onclick="selectAction('."'row".$index."'".')"/></td>';

        # option-tags for sorting entries. we need the numbers from 1 to n with n being the number of entries on the same level as the current entry.
        # set the number for the current entry into brackets 
        my $options;
        for (my $i = 1; $i < ((scalar @{$nodes})+1); $i++) {
           if ($i == $curNode) {
               $options .= '<option selected="selected" value="">('.$i.')</option>';
           }
           else {
               $options .= '<option value="'.$i.'">'.$i.'</option>';
           }
        }
        $curNode++;

        # entry is a folder
        if ($n->value()->path() eq '') {
            $wishlistHTMLedit .= '<td><select class="LC_hidden" name="sel" id="sel'.$index.'" onchange="submitSelect();">'.
                                 $options.'</select></td>'.
                                 '<td id="padd'.$index.'" style="padding-left:'.(($indent-$indentConst)<0?0:($indent-$indentConst)).'px;">'.
                                 '<a href="javascript:;" onclick="folderAction('."'row".$index."'".')" style="vertical-align:top" >'.
                                 '<img src="/adm/lonIcons/arrow.closed.gif" id="img'.$index.'" alt = ""  class="LC_icon"/>'.
                                 '<img src="/adm/lonIcons/navmap.folder.closed.gif" id="imgFolder'.$index.'" alt="folder"/></a>';

        }
        # entry is a link
        else {
            $wishlistHTMLedit .= '<td><select class="LC_hidden" name="sel" id="sel'.$index.'" onchange="submitSelect();">'.
                                 $options.'</select></td>'.
                                 '<td id="padd'.$index.'" style="padding-left:'.(($indent-$indentConst)<=0?$indentConst:$indent).'px;">'.
                                 '<img src="/res/adm/pages/wishlist-link.png" id="img'.$index.'" alt="link"/>';
        }

        # input-field for title
        $wishlistHTMLedit .= '<input type="text" name="newtitle" value="'.$n->value()->title().'" alt = "'.$n->value()->title().'"/></td>';

        # note-icon, different icons for an entries with note and those without
        my $noteIMG = 'anot.png';

        if ($n->value()->note() ne '') {
            $noteIMG = 'anot2.png';
        }

        $wishlistHTMLedit .= '<td style="padding-left:10px;"><a href="javascript:;" onclick="setDisplayNote('."'note".$index."'".')">'.
                             '<img id="noteImg'.$index.'" src="/res/adm/pages/'.$noteIMG.'" alt="'.&mt('Note').'" title="'.&mt('Note').'" '.
                             ' class="LC_icon"/></a></td>';

        $wishlistHTMLedit .= &Apache::loncommon::end_data_table_row();

        # start row containing the textarea for the note
        $wishlistHTMLedit .= &Apache::loncommon::continue_data_table_row('LC_hidden','note'.$index).
                             '<td></td><td></td><td>'.
                             '<textarea id="noteText'.$index.'" cols="25" rows="3" style="width:100%" '.
                             'name="newnote">'.
                             $n->value()->note().'</textarea></td><td></td>';
        $wishlistHTMLedit .= &Apache::loncommon::end_data_table_row();

        # if the entry is a folder, it could have other entries as content. if it has, call wishlistEdit for those entries 
        my @children = $n->children();
        if ($#children >=0) {
            $indent += 20;
            &wishlistEdit(\@children);
            $indent -= 20;
        }
    }
}



# HTML-Markup for table if in move-mode
my $wishlistHTMLmove ='<tr id="root" class="LC_odd_row"><td><input type="radio" name="mark" id="radioRoot" value="root" /></td>'.
                      '<td>'.&mt('Top level').'</td><td></td></tr>';
my $indent = $indentConst;
sub wishlistMove {
    my $nodes = shift;
    my $marked = shift;

    foreach my $n (@$nodes) {
        my $index = $n->value()->nindex();

        #find out wether the current entry was marked to be moved.
        my $isIn = 0;
        foreach my $m (@$marked) {
            if ($index == $m) {
               $isIn = 1;
            }
        }
        # start row and set class for even or odd row. this rows contains the title and the note-icon and can contain a radio-button
        $wishlistHTMLmove .= &Apache::loncommon::start_data_table_row('','row'.$index);


        # entry is a folder
        if ($n->value()->path() eq '') {
            # display a radio-button, if the folder was not selected to be moved
            if (!$isIn) {
                $wishlistHTMLmove .= '<td><input type="radio" name="mark" id="radio'.$index.'" value="'.$index.'" /></td>'.
                                     '<td id="padd'.$index.'" style="padding-left:'.(($indent-$indentConst)<0?0:($indent-$indentConst)).'px; min-width: 220px;">';
            }
            # higlight the title, if the folder was selected to be moved
            else {
                $wishlistHTMLmove .= '<td></td>'.
                                     '<td id="padd'.$index.'" style="padding-left:'.(($indent-$indentConst)<0?0:($indent-$indentConst)).'px; min-width: 220px;'.
                                     'color:red;">';
            }
            #arrow- and folder-image, all folders are open, and title
            $wishlistHTMLmove .= '<img src="/adm/lonIcons/arrow.open.gif" id="img'.$index.'" alt = "" />'.
                                 '<img src="/adm/lonIcons/navmap.folder.open.gif" id="imgFolder'.$index.'" alt="folder"/>'.
                                 $n->value()->title().'</td>';
        }
        # entry is a link
        else {
            if (!$isIn) {
                $wishlistHTMLmove .= '<td></td>'.
                                     '<td id="padd'.$index.'" style="padding-left:'.(($indent-$indentConst)<=0?$indentConst:$indent).'px; min-width: 220px;">';
            }
            # higlight the title, if the link was selected to be moved
            else {
                $wishlistHTMLmove .= '<td></td>'.
                                     '<td id="padd'.$index.'" style="padding-left:'.(($indent-$indentConst)<=0?$indentConst:$indent).'px; min-width: 220px;'.
                                     'color:red;">';
            }
            # link-image and title
            $wishlistHTMLmove .= '<img src="/res/adm/pages/wishlist-link.png" id="img'.$index.'" alt="link"/>'.
                                 $n->value()->title().'</td>';
        }

        # note-icon, different icons for an entries with note and those without
        my $noteIMG = 'anot.png';

        if ($n->value()->note() ne '') {
            $noteIMG = 'anot2.png';
        }

        $wishlistHTMLmove .= '<td style="padding-left:10px;"><a href="javascript:;" onclick="setDisplayNote('."'note".$index."'".')">'.
                             '<img id="noteImg'.$index.'" src="/res/adm/pages/'.$noteIMG.'" alt="'.&mt('Note').'" title="'.&mt('Note').'" '.
                             ' class="LC_icon"/></a></td>';

        $wishlistHTMLmove .= &Apache::loncommon::end_data_table_row();

        # start row containing the textarea for the note, readonly in move-mode
        $wishlistHTMLmove .= &Apache::loncommon::continue_data_table_row('LC_hidden','note'.$index).
                             '<td></td><td>'.
                             '<textarea id="noteText'.$index.'" cols="25" rows="3" style="width:100%" '.
                             'name="newnote" readonly="readonly">'.
                             $n->value()->note().'</textarea></td><td></td>'.
                             &Apache::loncommon::end_data_table_row();

        # if the entry is a folder, it could have other entries as content. if it has, call wishlistMove for those entries 
        my @children = $n->children();
        if ($#children >=0) {
            $indent += 20;
            &wishlistMove(\@children, $marked);
            $indent -= 20;
        }
    }
}

# Returns the HTML-Markup for wishlist
sub makePage {
    my $mode = shift;
    my $marked = shift;

    # breadcrumbs and start_page
    &Apache::lonhtmlcommon::clear_breadcrumbs();
    &Apache::lonhtmlcommon::add_breadcrumb(
              { href => '/adm/wishlist?mode='.$mode,
                text => 'Wishlist'});
    my $startPage = &Apache::loncommon::start_page('Wishlist',undef,
                                                     {'add_entries' => {
                                                        'onload' => 'javascript:onLoadAction('."'".$mode."'".');',
                                                        'onunload' => 'javascript:window.name = '."'loncapaclient'"}});

    my $breadcrumbs = &Apache::lonhtmlcommon::breadcrumbs('Wishlist '.
                           '<a title="Online-Hilfe" href="/adm/help/Wishlist.hlp" target="_top">'.
                           '<img src="/adm/help/help.png" alt="'.&mt('Help').'" '.
                           'title="'.&mt('Help').'" class="LC_icon" /></a>');

    # get javascript-code for wishlist-interactions
    my $js = &JSforWishlist();

    # texthash for items in funtionlist
    my %lt = &Apache::lonlocal::texthash(
                 'ed' => 'Edit',
                 'vw' => 'View',
                 'al' => 'Add Link',
                 'af' => 'Add Folder',
                 'mv' => 'Move Selected',
                 'dl' => 'Delete Selected',
                 'sv' => 'Save');

    # start functionlist
    my $functions = &Apache::lonhtmlcommon::start_funclist();

    # icon for edit-mode, display when in view-mode
    if ($mode eq 'view') {
        $functions .= &Apache::lonhtmlcommon::add_item_funclist('<a href="javascript:;" '.
                          'onclick="setFormAction('."'save','edit'".'); list.submit();" class="LC_menubuttons_link">'.
                          '<img src="/res/adm/pages/edit-mode-22x22.png" alt="'.$lt{'ed'}.'" '.
                          'title="'.$lt{'ed'}.'" class="LC_icon"/> '.
                          '<span class="LC_menubuttons_inline_text">'.$lt{'ed'}.'</span></a>');
    }
    # icon for view-mode, display when in edit-mode
    else {
        $functions .= &Apache::lonhtmlcommon::add_item_funclist('<a href="javascript:;" '.
                          'onclick="setFormAction('."'save','view'".'); list.submit();" class="LC_menubuttons_link">'.
                          '<img src="/res/adm/pages/view-mode-22x22.png" alt="'.$lt{'vw'}.'" '.
                          'title="'.$lt{'vw'}.'" class="LC_icon"/> '.
                          '<span class="LC_menubuttons_inline_text">'.$lt{'vw'}.'</span></a>');
    }
    
    # icon for adding a new link
    $functions .= &Apache::lonhtmlcommon::add_item_funclist('<a href="javascript:;" '.
                      'onclick="newLink();" class="LC_menubuttons_link">'.
                      '<img src="/res/adm/pages/link-new-22x22.png" alt="'.$lt{'al'}.'" '.
                      'title="'.$lt{'al'}.'" class="LC_icon"/>'.
                      '<span class="LC_menubuttons_inline_text">'.$lt{'al'}.'</span></a>');

    # icon for adding a new folder
    $functions .= &Apache::lonhtmlcommon::add_item_funclist('<a href="javascript:;" '.
                      'onclick="newFolder();" class="LC_menubuttons_link">'.
                      '<img src="/res/adm/pages/folder-new-22x22.png" alt="'.$lt{'af'}.'" '.
                      'title="'.$lt{'af'}.'" class="LC_icon"/>'.
                      '<span class="LC_menubuttons_inline_text">'.$lt{'af'}.'</span></a>');

    # icon for moving entries
    $functions .= &Apache::lonhtmlcommon::add_item_funclist('<a href="javascript:;" '.
                      'onclick="setFormAction('."'move','move'".'); " class="LC_menubuttons_link">'.
                      '<img src="/res/adm/pages/move-22x22.png" alt="'.$lt{'mv'}.'" '.
                      'title="'.$lt{'mv'}.'" class="LC_icon" />'.
                      '<span class="LC_menubuttons_inline_text">'.$lt{'mv'}.'</span></a>');

    # icon for deleting entries
    $functions .= &Apache::lonhtmlcommon::add_item_funclist('<a href="javascript:;" '.
                      'onclick="setFormAction('."'delete','".$mode."'".'); " class="LC_menubuttons_link">'.
                      '<img src="/res/adm/pages/del.png" alt="'.$lt{'dl'}.'" '.
                      'title="'.$lt{'dl'}.'" class="LC_icon" />'.
                      '<span class="LC_menubuttons_inline_text">'.$lt{'dl'}.'</span></a>');

    # icon for saving changes
    $functions .= &Apache::lonhtmlcommon::add_item_funclist('<a href="javascript:;" '.
                      'onclick="setFormAction('."'','".$mode."'".'); " class="LC_menubuttons_link">'.
                      '<img src="/res/adm/pages/save-22x22.png" alt="'.$lt{'sv'}.'" '.
                      'title="'.$lt{'sv'}.'" class="LC_icon" />'.
                      '<span class="LC_menubuttons_inline_text">'.$lt{'sv'}.'</span></a>');

    # end funtionlist and generate subbox 
    $functions.= &Apache::lonhtmlcommon::end_funclist();
    my $subbox = &Apache::loncommon::head_subbox($functions);

    # start form 
    my $inner .= '<form name="list" action ="/adm/wishlist" method="post">'.
                 '<input type="hidden" id="action" name="action" value=""/>';
 
    # only display subbox in view- or edit-mode
    if ($mode ne 'move') {
        $inner .= $subbox;
    }

    # generate table-content depending on mode
    if ($mode eq 'edit') {
        &wishlistEdit(\@childrenRt);
        if ($wishlistHTMLedit ne '') {
            $inner .= &Apache::loncommon::start_data_table("LC_tableOfContent");
            $inner .= $wishlistHTMLedit;
            $inner .= &Apache::loncommon::end_data_table();
        }
        else {
            $inner .= '<span class="LC_info">'.&mt("Your wihlist ist currently empty.").'</span>';
        }
        $wishlistHTMLedit = '';
    }
    elsif ($mode eq 'view') {
        &wishlistView(\@childrenRt);
        if ($wishlistHTMLview ne '') {
            $inner .= '<table class="LC_data_table LC_tableOfContent">'.$wishlistHTMLview.'</table>';
        }
        else {
            $inner .= '<span class="LC_info">'.&mt("Your wihlist ist currently empty.").'</span>';
        }
        $wishlistHTMLview = '';
    }
    else {
        my $markStr = '';
        foreach my $m (@$marked) {
            $markStr .= $m.',';
        }
        if ($markStr) {
            $markStr = substr($markStr, 0, length($markStr)-1);
            $inner .= '<input type="hidden" value="'.$markStr.'" name="markedToMove"/>';
            $inner .= '<span class="LC_info">'.&mt('You have selected the red marked entries to be moved to another folder. '.
                                                   'Now choose the new destination folder.').'</span><br/><br/>';
            &wishlistMove(\@childrenRt, $marked);
            $inner .= '<table class="LC_data_table LC_tableOfContent">'.$wishlistHTMLmove.'</table><br/><br/>';
            $inner .= '<input type="button" value="'.&mt('Move').'" onclick="setFormAction('."'','view'".'); selectDestinationFolder()"/>'.
                      '<input type="button" value="'.&mt('Cancel').'" onclick="go('."'/adm/wishlist'".')"/>';

            $wishlistHTMLmove ='<tr id="root" class="LC_odd_row"><td><input type="radio" name="mark" id="radioRoot" value="root" /></td>'.
                               '<td>'.&mt('Top level').'</td><td></td></tr>';
        }
        else {
            $inner .= '<span class="LC_info">'.&mt("You haven't marked any entry to move.").'</span><br/>'.
                      '<input type="button" value="'.&mt('Back').'" onclick="go('."'/adm/wishlist'".')"/>';
        }
    }
    
    # end form 
    $inner .= '</form>';

    # end_page 
    my $endPage =  &Apache::loncommon::end_page();

    # put all page-elements togther
    my $page = $startPage.$breadcrumbs.$js.$inner.$endPage;

    return $page;
}


# Returns the HTML-Markup for the page, shown when a link was set
sub makePageSet {
    # start_page 
    my $startPage = &Apache::loncommon::start_page('Wishlist',undef,
                                                   {'only_body' => 1});
    
    # confirm success and offer link to wishlist
    my $message = &Apache::lonhtmlcommon::confirm_success(&mt('Link successfully set!'));
    $message = &Apache::loncommon::confirmwrapper($message);

    my $inner .= '<br>'.$message.'<br/><br/>'.
                 '<a href="javascript:;" onclick="opener.open('."'/adm/wishlist'".');window.close();">'.&mt('Go to wishlist').'</a>'.
                 '&nbsp;<a href="javascript:;" onclick="window.close();">'.&mt('Close this window').'</a>';

    # end_page 
    my $endPage =  &Apache::loncommon::end_page();

    # put all page-elements togther
    my $page = $startPage.$inner.$endPage;

    return $page;
}


# Returns the HTML-Markup for error-page
sub makeErrorPage {
    # breadcrumbs and start_page 
    &Apache::lonhtmlcommon::add_breadcrumb(
              { href => '/adm/wishlist',
                text => 'Wishlist'});
    my $startPage = &Apache::loncommon::start_page('Wishlist');
    
    my $breadcrumbs = &Apache::lonhtmlcommon::breadcrumbs('Wishlist '.
                           '<a title="Online-Hilfe" href="/adm/help/Wishlist.hlp" target="_top">'.
                           '<img src="/adm/help/help.png" alt="'.&mt('Help').'" '.
                           'title="'.&mt('Help').'" class="LC_icon" /></a>');
    &Apache::lonhtmlcommon::clear_breadcrumbs();

    # error-message
    my $inner .= '<span class="LC_error">'.&mt('An error occurred! Please try again later.').'</span>';

    # end_page 
    my $endPage =  &Apache::loncommon::end_page();

    # put all page-elements togther
    my $page = $startPage.$breadcrumbs.$inner.$endPage;

    return $page;
}

# ----------------------------------------------------- Main Handler, package lonwishlist
sub handler {
    my ($r) = @_;
    &Apache::loncommon::content_type($r,'text/html');
    $r->send_http_header;

    if (&getWishlist() ne 'error') {
        # get wishlist entries from user-data db-file and build a tree out of these entries
        %TreeHash = &getWishlist();
        $root = &Tree::HashToTree();
        @childrenRt = $root->children();

        # greate a new entry
        if ($env{'form.title'}) {
           &newEntry($env{'form.title'}, $env{'form.path'}, $env{'form.note'});
        }

        # get unprocessed_cgi (i.e. marked entries, mode ...) 
        &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['action','mark','markedToMove','mode','newtitle','note']);

        # change the order of entries within a level, that means sorting the entries
        my $changeOrder = 0;
        if (defined $env{'form.sel'}) {
            my @sel = &Apache::loncommon::get_env_multiple('form.sel');
            my $indexNode;
            my $at;
            for (my $s=0; $s<($#sel+1); $s++) {
                if ($sel[$s] ne '') {
                    $indexNode = $s;
                    $at = $sel[$s]-1;
                }
            }
            if ($at ne '') {
                $changeOrder = 1;
                &sortEntries($indexNode,$at);
                &saveChanges();
            }
        }

        # get all marked (checkboxes) entries
        my @marked = ();
        if (defined $env{'form.mark'}) {
            @marked = &Apache::loncommon::get_env_multiple('form.mark');
        }

        # move entries from one folder to another
        if (defined $env{'form.markedToMove'}) {
           my $markedToMove = $env{'form.markedToMove'};
           my @ToMove = split(/\,/,$markedToMove);
           my $moveTo = $env{'form.mark'};
           if (defined $moveTo){ 
               &moveEntries(\@ToMove,$moveTo);
               &saveChanges();
           }
           $changeOrder = 1;
    
        }

        # delete entries
        if ($env{'form.action'} eq 'delete') {
            &deleteEntries(\@marked);
        }
   

        # get all titles and notes and save them
        # only save, if user wants to save changes
        # do not save, when current action is 'delete' or 'sort' or 'move' 
        my @newTitles = ();
        my @newNotes = ();
        if ((defined $env{'form.newtitle'} || defined $env{'form.newnote'}) && ($env{'form.action'} ne 'noSave') && ($env{'form.action'} ne 'delete') && !$changeOrder) {
            @newTitles = &Apache::loncommon::get_env_multiple('form.newtitle');
            @newNotes = &Apache::loncommon::get_env_multiple('form.newnote');
            my $node = 0;
            foreach my $t (@newTitles) {
               &setNewTitle($node, $t);
               $node++;
            }
            $node = 0;
            foreach my $n (@newNotes) {
               &setNewNote($node, $n);
               $node++;
            }
            &saveChanges();
        }

        # Create HTML-markup
        my $page;
        if ($env{'form.mode'} eq 'edit') {
            $page = &makePage("edit");
        }
        elsif ($env{'form.mode'} eq 'move') {
            $page = &makePage("move", \@marked);
        }
        elsif ($env{'form.mode'} eq 'set') {
            $page = &makePageSet();
        }
        else {
            $page = &makePage("view");
        }
        @marked = ();
        $r->print($page);
    }
    # An error occured, print an error-page
    else {
        my $errorPage = &makeErrorPage();
        $r->print($errorPage);
    }
    return OK;
}

# ----------------------------------------------------- package Tree
# Extend CPAN-Module Tree by function like 'moveNode' or 'deleteNode'
package Tree;

# returns the node with a given index from a list of nodes
sub getNodeByIndex {
    my $index = shift;
    my $nodes = shift;
    my $found;
    
    for my $n (@$nodes) {
        my $curIndex = $n->value()->nindex();
        if ($n->value()->nindex() == $index) {
            $found = $n;
        }
    }
    return $found;
}

# moves a given node to a new parent or change the position from a node
# within its siblings (sorting)
sub moveNode {
    my $node = shift;
    my $at = shift;
    my $newParent = shift;


    if (!$newParent) {
        $newParent = $node->parent();
    }

    $node->parent()->remove_child($node);

    if (defined $at) {
        $newParent->add_child({at => $at},$node);
    }
    else {
        $newParent->add_child($node);
    }
    
    # updating root's children
    @childrenRt = $root->children();
}

# removes a given node
sub removeNode() {
    my $node = shift;
    my @children = $node->children();

    if ($#children >= 0) {
        foreach my $c (@children) {
            &removeNode($c);
        }
    }
    $node->parent()->remove_child($node);

    # updating root's children
    @childrenRt = $root->children();
}


# set an index for every node in the tree, beginning with 0
my $count = 0;
sub TreeIndex {
    my $children = shift;

    foreach my $n (@$children) {
        my @children = $n->children();
        $n->value()->nindex($count);$count++;

        if ($#children>=0) {
            &TreeIndex(\@children);
        }
    }
}

# reset index counter
sub setCountZero {
    $count = 0;
}


# convert the tree to a hash
# each node is one hash-entry
# keys are the indices, values are all other attributes
# (containing tile, path, note, date and indices for all direct children)
# except for root: the key is root and values are
# just the indices of root's children
sub RootToHash {
    my $childrenRt = shift;
    my @indexarr = ();

    foreach my $c (@$childrenRt) {
       push (@indexarr, $c->value()->nindex());
    }
    $TreeToHash{'root'} = [@indexarr];
}

sub TreeToHash {
    my $childrenRt = shift;

    foreach my $n (@$childrenRt) {
        my @arrtmp = ();
        $arrtmp[0] = $n->value()->title();
        $arrtmp[1] = $n->value()->path();
        $arrtmp[2] = $n->value()->note();
        $arrtmp[3] = $n->value()->date();
        my @childrenRt = $n->children();
        my $co = 4;
        foreach my $c (@childrenRt) {
            my $i = $c->value()->nindex();
            $arrtmp[$co] = $i;
            $co++;
        }
        $TreeToHash{$n->value()->nindex} = [ @arrtmp]; 
        if ($#childrenRt>=0) {
            &TreeToHash(\@childrenRt);
        }
    }
}


# convert the hash to a tree
# build a tree-object for each entry in the hash
# afterwards call &buildTree to connect the tree-objects
sub HashToTree {
    my @TreeNodes = ();
    my $root;

    foreach my $key (keys %TreeHash) {
        if ($key eq 'root') {
            $root = Tree->new("root");
        }
        else {
        my @attributes = @{ $TreeHash{$key} };
        my $tmpNode;
            $tmpNode = Tree->new(Entry->new(title=>$attributes[0],
                                            path=>$attributes[1],
                                            note=>$attributes[2],
                                            date=>$attributes[3],
                                            nindex=>$key));
        push(@TreeNodes, $tmpNode);
        # shift all attributes except for
        # the indices representing the children of a node
        shift(@attributes);
        shift(@attributes);
        shift(@attributes);
        shift(@attributes);
        $TreeHash{$key} = [ @attributes ];
        }
    }
    # if there are nodes, build up the tree-structure
    if (defined $TreeHash{'root'}) {
        my @childrenRtIn = @{ $TreeHash{'root'} };
        &buildTree(\$root, \@childrenRtIn,\@TreeNodes,\%TreeHash);
    }
    return $root; 
}


# join the nodes to a tree
sub buildTree {
    my ($node, $childrenIn, $TreeNodes, $TreeHash) = @_;
    bless($node, 'Tree');
    foreach my $c (@$childrenIn) {
        my $tmpNode =  &getNodeByIndex($c,$TreeNodes);
        $$node->add_child($tmpNode);
        my @childrenIn = @{ $$TreeHash{$tmpNode->value()->nindex()} };
        &buildTree(\$tmpNode,\@childrenIn,$TreeNodes,$TreeHash);
    }

}


# ----------------------------------------------------- package Entry
# package that defines the entrys a wishlist could have
# i.e. folders and links
package Entry;

# constructor
sub new {
    my $invocant = shift;
    my $class = ref($invocant) || $invocant;
    my $self = { @_ }; #set attributes
    bless($self, $class);
    return $self;    
}

# getter and setter
sub title {
    my $self = shift;
    if ( @_ ) { $self->{title} = shift}
    return $self->{title};
}

sub date {
    my $self = shift;
    if ( @_ ) { $self->{date} = shift}
    return $self->{date};
}

sub note {
    my $self = shift;
    if ( @_ ) { $self->{note} = shift}
    return $self->{note};
}

sub path {
    my $self = shift;
    if ( @_ ) { $self->{path} = shift}
    return $self->{path};
}

sub nindex {
    my $self = shift;
    if ( @_ ) { $self->{nindex} = shift}
    return $self->{nindex};
}


1;
__END__