function onDeviceReady(){
    //global variables, bad practice I know
    user = 'user';
    pass = 'pass';
    deviceID = device.uuid;
    console.log(deviceID);
    db = window.sqlitePlugin.openDatabase({name: 'mood.db', location: 'default'},function(){
        db.transaction(function(tx){
            tx.executeSql('CREATE TABLE IF NOT EXISTS update_table (uid integer primary key autoincrement, timestamp)',[],function(){},function(e){
                console.log(e.message);
            });
            tx.executeSql('CREATE TABLE IF NOT EXISTS mood_table (uid integer primary key autoincrement, uuid, id, smileyid, textdata, activity, created, last_change, deleted)',[],function(){},function(e){
                console.log(e.message);
            });
            tx.executeSql('SELECT * FROM update_table',[],function(tx, res){
                if(res.rows.length === 0){
                    tx.executeSql('INSERT INTO update_table (timestamp) VALUES (?)',[0],function(){},function(e){
                        console.log(e.message);
                    });
                }
            },function(e){
                console.log(e.message);
            });
            checkForUpdates();
        },function(e){
            console.log(e.message);
        });
    },function(e){
        console.log(JSON.stringify(e));
    });
}

function make_base_auth(username, password) {
    var tok = username + ':' + password;
    var hash = btoa(tok);
    return 'Basic ' + hash;
}

function checkForUpdates(){
    console.log('checkForUpdates');
    //internet connection check
    if(navigator.connection.type != Connection.NONE) {
        db.executeSql('SELECT * FROM update_table WHERE uid = 1',[],function(res){
            var data,
                new_tsmp,
                tsmp = (typeof res.rows.item(0).timestamp === undefined) ? '0' : res.rows.item(0).timestamp;
            console.log(tsmp);
            $.when(
                $.ajax({
                    url: 'http://mydomain.de/my.php',
                    crossDomain: true,
                    timeout: 30000,
                    method: 'GET',
                    dataType: 'text',
                    data: {'command': 'check_update',
                            'unix_time': tsmp,
                            'uuid': deviceID},
                    xhrFields: {
                        withCredentials: true
                    },
                    beforeSend: function(xhr){
                        xhr.setRequestHeader('Authorization', make_base_auth(user, pass));
                    },
                    success: function(textdata, status, jqXHR){
                        data = $.parseJSON(textdata);
                        //check for updates
                        console.log(JSON.stringify(data));
                        console.log(status);
                    },
                    error: ajaxErrorCb
                })
            ).done(function(){
                switch(data.case){
                    case 'update':
                        //update
                        new_tsmp = data.timestamp;
                        $.makeArray(data.notes_id).forEach(function(ele, i){
                            if(data.deleted[i] === '0'){
                                getData(ele);
                            } else {
                                removeData(data.uuid[i], data.id[i]);
                            }
                        });
                        break;
                    case 'stay':
                        //???
                        new_tsmp = tsmp;
                        populate();
                        break;
                    default:
                        console.log('something is not right');
                }
                updateTimestamp(new_tsmp);
            });
        },function(e){
            console.log(e.message);
        });
    } else {
        //popup??
        alert('Die Daten können nicht mit dem Server synchronisiert werden, da keine Internetverbindung vorhanden ist.')
        populate();
    }
}

function removeData(uuid, id){
    db.executeSql('DELETE FROM mood_table WHERE uuid = ? AND id = ?',[uuid, id],function(){
        console.log('removed: '+uuid+', '+id);
    },function(e){
        console.log(e.message);
    })
}

function updateTimestamp(tsmp){
    db.executeSql('UPDATE update_table SET timestamp = ? WHERE uid = 1',[tsmp],function(){},function(e){
        console.log(e.message);
    });
}

/**
 *Downloads data from the server and inserts it into the local database.
 *@param {integer} id - The id of the row that will be downloaded
 */
function getData(id){
    $.ajax({
        url: 'http://mydomain.de/my.php',
        crossDomain: true,
        timeout: 30000,
        method: 'GET',
        dataType: 'json',
        data: {'command': 'get_update_data',
                'id': id},
        xhrFields: {
            withCredentials: true
        },
        beforeSend: function(xhr){
            xhr.setRequestHeader('Authorization', make_base_auth(user, pass));
        },
        success: function(data,status,jqXHR){
            //insert updated data
            console.log(JSON.stringify(data));
            var activityArr = new Array(),
                smileyimg = getSmileyImg(data.smileyid, data.id),
                activityValues = data.activity.split(","),
                date = new Date(parseInt(data.created, 10)),
                dd = date.getDate(),
                mm = date.getMonth()+1, //January is 0!
                yyyy = date.getFullYear(),
                hh = date.getHours(),
                mins = date.getMinutes();
            if(dd<10) {
                dd='0'+dd;
            }
            if(mm<10) {
                mm='0'+mm;
            }
             if(mins<10) {
                mins='0'+mins;
            }
            var created = hh+':'+mins+' '+dd+'.'+mm+'.'+yyyy,
            activityValues.forEach(function(ele, i){
                if(ele == 1){
                    activityArr.push(getActivity(i));
                }
            });
            //check uuid & id
            db.transaction(function(tx){
                tx.executeSql('SELECT * FROM mood_table WHERE uuid = ? AND id = ?',[data.uuid, data.id],function(tx, res){
                    if(res.rows.length != 0){
                        tx.executeSql('UPDATE mood_table SET smileyid = ?, textdata = ?, activity = ?, last_change = ?, deleted = ? WHERE uuid = ? AND id = ?',[data.smileyid, data.textdata, data.activity, data.last_change, data.deleted, data.uuid, data.id],function(){
                            console.log('insert success');
                        },function(e){
                            console.log(e.message);
                        });
                    } else {
                        tx.executeSql('INSERT INTO mood_table (uuid, id, smileyid, textdata, activity, created, last_change, deleted) VALUES (?,?,?,?,?,?,?,?)',[data.uuid, data.id, data.smileyid, data.textdata, data.activity, created, data.last_change, data.deleted],function(){
                            console.log('insert succes');
                        },function(e){
                            console.log(e.message);
                        });
                    }
                },function(e){
                    console.log(e.message);
                });
                //populate?
                $('#mytext').prepend('<div class="mytextarea" id="'+data.id+'"></div>');
                if(data.uuid == deviceID){
                    $('#'+data.id).append('<a href="#popupDialog" data-rel="popup" data-position-to="window" class="ui-btn ui-shadow ui-corner-all ui-nodisc-icon ui-alt-icon ui-icon-bars ui-btn-icon-notext ui-btn-inline delete-button" onclick="openPopup('+data.id+');"></a>');
                } else {
                    $('#'+data.id).append('</br>');
                }
                $('#'+data.id).append(smileyimg+'<p id="'+data.id+'-text" style="margin-top: 10px;">'+data.textdata+'</p><p><div id="taetigkeiten_'+data.id+'"></div>'+created+'</p>');
                $('#taetigkeiten_'+data.id).text('Tätigkeiten: ');
                $('#taetigkeiten_'+data.id).append(activityArr.join(', '));
                graphMalen(smileyArr);
            });
        },
        error: ajaxErrorCb
    });
}

/**
 *Uploads data to the server.
 *@param {integer} id - ID of the div
 *@param {integer} smileyid - ID of the smiley
 *@param {string} text - Descriptiontext
 *@param {integer} activity - ID of the activity
 *@param {string} date - Date and time of the creatino
 */
function insertData(id, smileyid, text, activity){
    var insertObj = {
        'command': 'insert_data',
        'uuid': deviceID,
        'id': id,
        'smileyid': smileyid,
        'text': text,
        'activity': activity.join(',')
    };
    $.ajax({
        url: 'http://mydomain.de/my.php',
        crossDomain: true,
        timeout: 30000,
        method: 'POST',
        dataType: 'text',
        data: insertObj,
        xhrFields: {
            withCredentials: true
        },
        beforeSend : function(xhr){
            xhr.setRequestHeader('Authorization', make_base_auth(user, pass));
        },
        success: function(data,status){
            console.log(JSON.stringify(data));
            console.log(status);
        },
        error: ajaxErrorCb
    });
}

function ajaxErrorCb(obj, text, e){
    console.log(JSON.stringify(obj));
    console.log(text);
}

{'case': string,
'notes_id': integer,
'uuid': string,
'id': integer,
'deleted': integer,
'timestamp': integer}

{'uuid': string,
'id': integer,
'smileyid': integer,
'textdata': string,
'activity': string,
'timedate': integer,
'created': integer,
'last_change': integer,
'deleted': integer}