function applyFilter(thisdir) {

    var pattern = prepareSearchPattern();
    var translations = jQuery.parseJSON(localStorage.getItem('CSTRtrans')).translations;

    updateDisplay(pattern, translations);
    filterTableElements(pattern);
    filterOtherElements(pattern, translations, thisdir);
}

// called everytime the user makes an input into the search field
function updateDisplay(pattern, translations) {
    var header1 = document.getElementById('searchtitle');

    if (pattern.source == '(?:)'){
        header1.style.display = 'none';
    } else {
        // remove escape symbol for better readability
        header1.innerHTML = translations.results+' '+pattern.source.replace('\\','');
        header1.style.display = '';
    }
}

// filters the contents table of the authoring space to only show matching resources in the current dir
function filterTableElements(pattern) {
    var list = document.getElementsByClassName('LC_data_table')[0].childNodes[1].children;

    // i=2 to skip searchtitle and header
    for (var i = 2; i < list.length; i++){
        // get filename: table column,     <span>,       <a>,       name
        var resname = list[i].children[2].children[0].children[0].innerHTML;
        var restitle;

        // check if resource has title and get it
        var titleColumn = list[i].children[3].children;

        if (titleColumn.length > 2){
            restitle = titleColumn[0].innerHTML;
        } else {
            restitle = '';
        }

        // match in filename OR resource title OR if search string is empty
        if ( pattern.test(resname) || pattern.test(restitle) || pattern.source == '' ){
            list[i].style.display = '';     // show element
        } else {
            list[i].style.display = 'none'; // hide element
        }
    }
}

// this is the search function for resources in other locations.
// pattern - the search pattern given by the user
// translations - loncapa generated translation object for the user interface
// thisdir - dir the user is currently in, used to generate relativ links for found files
function filterOtherElements (pattern, translations, thisdir) {

    var otherfiles = jQuery.parseJSON(sessionStorage.getItem('CSTRcache')).resources;
    if (pattern.source == '(?:)'){
        document.getElementById('otherplaces').style.display = 'none';
        return;
    }

    var hits = new Array();
    for (var i = 0; i < otherfiles.length; i++){
        if (otherfiles[i].title == '[untitled]'){
            otherfiles[i].title = '';
        }

        if ( pattern.test(otherfiles[i].name) || pattern.test(otherfiles[i].title) ){
            hits.push(otherfiles[i]);
        }
    }
    if (hits.length < 1){
        document.getElementById('otherplaces').style.display = 'none';
    } else {
        document.getElementById('otherplaces').style.display = '';
        var element = document.getElementsByName("otherplacescontent");

        // remove all old children
        for (index = element.length - 1; index >= 0; index--){
            element[index].parentNode.removeChild(element[index]);
        }

        // add new children
        for (var i = 0; i < hits.length; i ++){
            document.getElementById('otherplacestable').parentNode.appendChild(renderRow(hits[i], i, translations, thisdir));
        }
    }
}

// adds an row to the other places result table, used by filterOtherElements()
function renderRow(element, i, translations, thisdir) {
    var isdir = false;
    var row = '';
// icon
    row += '<td>';
    var extension = /\.(.+?)$/;

    if (element.name.match(extension)){
        var allowed = ['avi','cab','doc','dvi','eps','exam','htm','html','jar','jpeg','jpg','library','mov','mpeg','mpg','page','pdf','png','ppt','problem','ps','qt','quiz','sequence','spreadsheet','survey','task','tex','text','tth','txt','wav','wmv','xls','xml','zip'];
        var match = extension.exec(element.name)[1];
        if (allowed.indexOf(match) > -1) {
            // is supported file type
            row += '<img src="/adm/lonIcons/'+match+'.gif" alt="" />';
        } else {
            // is some other file we dont have an icon for
            row += '<img src="/adm/lonIcons/srvnull.gif" alt="" />';
        }
    } else {
        // is a directory
        isdir = true;
        row += '<img src="/adm/lonIcons/navmap.folder.closed.gif" alt="" />';
    }

    element.path = element.path.replace(/^\/home\/httpd\/html\//,'\/');

// directory
    var location = element.path.replace(/\/priv\//,'');
    if (location == ''){ location = '/'; }
    row += '</td><td>';
    if (isdir) {
        row += '<a href="/priv/'+location+'" target="_parent"></a>';
    } else {
        row += '<a href="/priv/'+location+'" target="_parent">'+location.replace(/(.+?)\/(.+?)\//,'/')+'</a>';
    }
    row += '</td><td>';

    if (isdir) {

    // file link
        row += '<span class="LC_filename"><a href="'+element.path+'/" target="_parent">'+element.name+'</a></span> <br />';
        row += '</td><td></td>';
    // status
        row += '<td class="LC_browser_file_'+element.status+'">&nbsp;&nbsp;</td><td>'+translations.directory+'</td>';
        row += '<td>'+element.cmtime+'</td></tr>';
    } else {
    
    // file link
        row += '<span class="LC_filename"><a href="'+element.path+element.name+'" target="_parent">'+element.name+'</a></span> <br />';
    // editor
        row += '(<a href="'+element.path+element.name+'?editmode=Edit&amp;problemmode=edit">'+translations.edit+'</a>)';
    // xml editor
        row += '(<a href="'+element.path+element.name+'?editmode=Edit&amp;problemmode=editxml">'+translations.editxml+'</a>)';
        row += '</td><td>';
    // edit metadata
        row += '<a href="'+element.path+element.name+'.meta" target="cat">'+element.title+'</a><br />'
        row += '<a href="'+element.path+element.name+'.meta">'+translations.editmeta+'</a>';
        row += '</td>';
    // status
        row += '<td class="LC_browser_file_'+element.status+'">&nbsp;&nbsp;</td><td>'+translations[element.status]+'</td>';
        row += '<td>'+element.cmtime+'</td></tr>';
    }

    var result = document.createElement('tr');
    result.innerHTML += row;
    result.setAttribute('name', 'otherplacescontent');
// set row style
    if (i % 2 == 1){
        result.setAttribute('class', 'LC_odd_row');
    } else {
        result.setAttribute('class', 'LC_even_row');
    }
    return result;
}

// escapes the search pattern for on screen display
function prepareSearchPattern() {
    var searchstring = document.getElementById('quickfilter').value;
    var regopt = document.getElementById('casesens').checked?'':'i';

    if (document.getElementById('regex').checked == false) {
        searchstring = searchstring.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');
    } else {
        // a single \ at the end would escape the closing / of the regex
        searchstring = searchstring.replace(/\\$/, '\\\\');
    }
    return new RegExp(searchstring, regopt);
}