/* 
 *   Copyright (C) 2014
 *   This file is part of WvS VPlan.
 *
 *   WvS VPlan is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU Affero General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program 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 Affero General Public License for more details.
 *
 *   You should have received a copy of the GNU Affero General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

// Login-Popup beim Start
$('#mainpage').on('pagebeforeshow', function(){
    setTimeout(function(){
        load();
        $('#lnklogin').click();
    }, 500);
});

$('#mainpage').on('pageshow', function(){
    setTimeout(function(){
        trylogin();
    }, 2000);
});

/* PDF Rendering */
function renderPage(div, pdf, pageNumber, callback){
    pdf.getPage(pageNumber).then(function(page){
        var scale = 2;
        var viewport = page.getViewport(scale);

        var pageDisplayWidth = viewport.width;
        var pageDisplayHeight = viewport.height;

        var pageDivHolder = document.createElement('div');
        pageDivHolder.className = 'pdfpage';

        var $canvas = $('<canvas></canvas>');
        var canvas = $canvas.get(0);
        canvas.className = 'pdfcanvas';
        var context = canvas.getContext('2d');
        canvas.width = pageDisplayWidth;
        canvas.height = pageDisplayHeight;

        pageDivHolder.appendChild(canvas);
        div.appendChild(pageDivHolder);

        var renderContext = {
            canvasContext: context,
            viewport: viewport
        };
        page.render(renderContext).promise.then(callback);
    });
}

function render_pdf(url, divstr){
    console.log('Rendere PDF: ' + url + ' (' + divstr + ')');

    PDFJS.getDocument(url).then(function(pdf){
        var viewer = document.getElementById(divstr);
        var pageNumber = 1;
        renderPage(viewer, pdf, pageNumber++, function pageRenderingComplete(){
            if(pageNumber > pdf.numPages){
                return;
            }
            renderPage(viewer, pdf, pageNumber++, pageRenderingComplete);
        });
    });
}

/* wird bei Verbindungsfehlern oder anderen Fehlern aufgerufen */
function fail(text){
    $('#loginform').removeClass('ui-disabled');
    $('#loader').hide('slow');
    $('#error_noconn').show('fast');
    console.log('Fehler: ' + text.toString() + ' / ' + text.code);
}

/* fügt die lokale URL des Plans ein und ruft die Seite zum Rendering auf */
function addplanattr(fileEntry){
    var sPath = fileEntry.toURL();
    var name = fileEntry.name.replace('.pdf', '');

    console.log('Dateiname: ' + name);

    var vplantabs = $('#vplantabs').tabs();
    var ul = vplantabs.find('ul');
    $('<li><a href="#' + name + '">' + name + '</a></li>').appendTo(ul);
    $('<div id="' + name + '"></div>').appendTo(vplantabs);

    render_pdf(sPath, name);
    vplantabs.tabs('refresh'); // TODO geht nicht
}

/* lädt ein PDF anhand eines Links herunter, benötigt ID zur Sortierung */
function download_pdf(link){
    var filename = link.substring(link.lastIndexOf("/") + 1);

    window.requestFileSystem(
    LocalFileSystem.PERSISTENT, 0,
    function(fileSystem){
        fileSystem.root.getDirectory('WvSVPlan', {create: true, exclusive: false},
        function(dirEntry){
            dirEntry.getFile(filename, {create: false, exclusive: false},
            function(fileEntry){
                // Datei ist schon heruntergeladen
                console.log('lade Datei nicht erneut herunter');
                addplanattr(fileEntry);
            },
        function(err){
            // Datei existiert noch nicht
            dirEntry.getFile(filename, {create: true, exclusive: false},
            function(fileEntry){
                var fileTransfer = new FileTransfer();

                fileTransfer.download(
                link,
                fileEntry.toURL(),
                function(theFile){
                    console.log('Download fertig: ' + theFile.toURL());
                    addplanattr(theFile);
                    }, fail);
                }, fail);
            });
        }, fail);
    });
}

/* sucht den Downloadlink eines Plans mithilfe eines Links aus der Kursübersicht */
function get_plan(link){
    var request = $.ajax({
        url: link
    });

    request.done(function gotplan(resulthtml){
        var pdf_re = new RegExp('(http://***REMOVED***\\.de/moodle/pluginfile\\.php/\\d+/mod_resource/content/\\d+/.*?\\.pdf)');
        var pdflink = pdf_re.exec(resulthtml)[1];

        if(pdflink == null){
            return 0;
        }

        console.log('Plan gefunden: ' + pdflink);
        download_pdf(pdflink);

        return 1;
    });

    request.fail(fail);
}

/* ruft get_plan für jeden Link in der Kursübersicht auf */
function gotoverview(resulthtml){
    var plans_re = new RegExp('window\\.open\\(&#039;(http://***REMOVED***\\.de/moodle/mod/resource/view\\.php\\?id=\\d+)&amp;redirect=1&#039;\\)', 'g');

    var resultarr = resulthtml.match(plans_re);

    if(resultarr == null){
        $('#error_passwd').show('fast');
        $('#loginform').removeClass('ui-disabled');
        $('#loader').hide('slow');
        return 0;
    }

    var resultl = resultarr.length;

    while((link = plans_re.exec(resulthtml)) !== null){
        console.log('suche Plan ' + link[1]);
        get_plan(link[1]);
    }

    console.log('Übersichts-Request erfolgreich');
    return 1;
}

/* holt die Kursübersicht - bei Verbindungsfehlern wird onfail aufgerufen */
function get_overview(link, onfail){
    var request = $.ajax({
        url: link
    });

    console.log('Hole Übersicht');

    request.done(gotoverview);
    request.fail(onfail);
}

/* such den Link zur Übersicht von der Startseite aus */
function loggedin(resulthtml){
    var vertretungs_re = new RegExp('title="Vertretungsplan" href="(http://***REMOVED***\\.de/moodle/course/view\\.php\\?id=\\d+)"');
    var link = vertretungs_re.exec(resulthtml)[1];

    if(link == null){
        return 0;
    }

    window.localStorage.setItem('overviewlink', link);
    console.log('Eingeloggt');
    get_overview(link, fail);

    return 1;
}

/* sendet einen HTTPost-Request mit Logindaten */
function sendlogin(username, password){
    var params = 'username=' + username + '&password=' + password;

    $('#loginform').addClass('ui-disabled');
    $('#loader').show('fast');
    
    $('#error_noconn').hide('fast');
    $('#error_passwd').hide('fast');
    
    var request = $.ajax({
        type: 'POST',
        url: 'https://***REMOVED***/moodle/login/index.php',
        data: {username: username, password: password}
    });

    console.log('Logge ein');

    request.done(loggedin);
    request.fail(fail);
}

/* lädt Benutzerdaten 1) aus den Userinterfaces oder 2) aus dem HTML5 Local Storage */
/* oder 3) gibt null zurück */
function getuserdata(){
    var username = encodeURIComponent($('#username').val());

    if(username == ''){
        username = window.localStorage.getItem('username');
    }else{
        window.localStorage.setItem('username', username);
    }

    var password = encodeURIComponent($('#password').val());
    if(password == ''){
        password = window.localStorage.getItem('password');
    }else{
        window.localStorage.setItem('password', password);
    }

    console.log('Benutzerdaten geladen');

    if(username !== 'undefined' && username != null && username != '' && password !== 'undefined' && password != null && password != ''){
        return [username, password];
    }else{
        return null;
    }
}

/* loggt ein oder zeigt Loginform */
function login(){
    userdata = getuserdata();

    if(userdata != null){
        sendlogin(userdata[0], userdata[1]);
        return 1;
    }else{
        $('#loginform').removeClass('ui-disabled');
        $('#loader').hide('fast');
        return 0;
    }
}

/* versucht ohne HTTPost die Übersicht zu holen */
/* bei einem Fehlschlag wird in login() versucht, die Nutzerdaten zu laden */
/* und wenn das schiefläuft, muss der Nutzer seine Daten selbst eingeben */
function trylogin(){
    var link = window.localStorage.getItem('overviewlink');

    $('#loginform').addClass('ui-disabled');
    $('#loader').show('fast');

    if(typeof link !== 'undefined' && link != null){
        console.log('Teste Login');
        console.log(link);

        get_overview(link, login);
    }else{
        login();
    }
}

/* gibt aktuelle Pläne aus entries zurück */
function getactual(entries){
    var fname_re = new RegExp('([^-]{4})-([^-]{2})-([^-]{2})(.*?)\.pdf'); // \d funktioniert nicht
    var today = new Date();
    var actual = [];

    entries.forEach(function(entry){
        console.log(entry.name);
        var results = entry.name.match(fname_re);
        var fdate = new Date(parseInt(results[1]), parseInt(results[2]) - 1, parseInt(results[3]));

        if(fdate >= today){
            actual.push(entry);
        }
    });

    return actual;
}

/* lädt Vertretungspläne aus dem Speicher [1) SD-Karte oder 2) dem internen Speicher] */
function load(){
    window.requestFileSystem(
    LocalFileSystem.PERSISTENT, 0,
    function(fileSystem){
        fileSystem.root.getDirectory('WvSVPlan', {create: true, exclusive: false},
        function(dirEntry){
            var dirReader = dirEntry.createReader();

            dirReader.readEntries(
            function(entries){
                var actual = getactual(entries);

                console.log("Im Speicher: " + actual.length + " Pläne");

                if(actual.length > 0){
                    for(j = 0; j < actual.length; j++){
                        addplanattr(actual[j]);
                    }
                }else{

                }
            }, fail);
        }, fail);
    });
}