function startApp() {
    sessionStorage.clear();
    showHideMenuLinks();
    showView('viewHome');

    // Bind the navigation menu links
    $('#linkHome').click(showHomeView);
    $('#linkLogin').click(showLoginView);
    $('#linkRegister').click(showRegisterView);
    $('#linkListAds').click(showCollectionView);
    $('#linkCreateAd').click(showCreateView);
    $('#linkLogout').click(logout);

    // Bind the form submit buttons
    $("#formLogin").submit(login);
    $("#formRegister").submit(register);
    $("#buttonCreateAd").click(create);
    $("#buttonEditAd").click(edit);

    // Bind the info / error boxes: hide on click
    $("#infoBox, #errorBox").click(function() {
        $(this).fadeOut();
    });
    $(document).on({
        ajaxStart: function() { $("#loadingBox").show() },
        ajaxStop: function() { $("#loadingBox").hide() }
    });

    // Show or hide the links in the navigation bar
    function showHideMenuLinks() {
        $("#linkHome").show();
        if (sessionStorage.getItem('authToken')) {
            // We have logged in user
            $("#linkLogin").hide();
            $("#linkRegister").hide();
            $("#linkListAds").show();
            $("#linkCreateAd").show();
            $("#linkLogout").show();
        } else {
            // No logged in user
            $("#linkLogin").show();
            $("#linkRegister").show();
            $("#linkListAds").hide();
            $("#linkCreateAd").hide();
            $("#linkLogout").hide();
        }
    }

    // Hide all views and show the selected view only
    function showView(viewName) {
        $('main > section').hide();
        $('#' + viewName).show();   // viewName is the id of the given section
    }

    //-----Views----------------------------------------------------------------------//

    function showHomeView() {
        showView('viewHome');
    }
    //---------------------------
    function showLoginView() {
        showView('viewLogin');
        $('#formLogin').trigger('reset');
    }
    //----------------------------
    function showRegisterView() {
        showView('viewRegister');
        $('#formRegister').trigger('reset');
    }
    //----------------------------
    function showCollectionView() {
        $('#ads').empty();
        showView('viewAds');
        KinveyRequester.findAllEntities()
            .then(loadSuccess)
            .catch(handleAjaxError);
        function loadSuccess(response) {
            showInfo('Entities loaded.');
            if (response.length == 0) {
                $('#ads').text('The collection is empty.');
            }
            else {
                let table = $('<table>')
                    .append($('<tr>').append(
                        '<th>Title</th><th>Body</th><th>Author</th>,' +
                        '<th>Date</th><th>Actions</th>'));
                for (let entity of response) {
                    let links = [];
                    // action links
                    if (entity._acl.creator == sessionStorage['userID']) {
                        let deleteLink = $('<a href="#">[Delete]</a>')
                            .click(function () {
                                deleteIt(entity)
                            });
                        let editLink = $('<a href="#">[Edit]</a>')
                            .click(function () {
                                loadForEdit(entity)
                            });
                        links = [deleteLink, ' ', editLink];
                    }

                    table.append($('<tr>').append(
                        $('<td>').text(entity.title),
                        $('<td>').text(entity.body),
                        $('<td>').text(entity.author),
                        $('<td>').text(entity.date),
                        $('<td>').append(links)
                    ));
                }
                $('#ads').append(table);
            }
        }
    }
    //-------------------------
    function showCreateView() {
        $('#formCreateAd').trigger('reset');
        showView('viewCreateAd');
    }
    //--------------------------
    function loadForEdit(entity) {
        KinveyRequester.findEntityById(entity)
            .then(loadForEditSuccess)
            .catch(handleAjaxError);
        function loadForEditSuccess(entity) {
            $('#formEditAd input[name=id]').val(entity._id);
            $('#formEditAd input[name=title]').val(entity.title);
            $('#formEditAd textarea[name=description]').val(entity.body);
            $('#formEditAd input[name=datePublished]').val(entity.date);
            showView('viewEditAd');
        }
    }
    //-----Actions without a view------------------------------------------------------//

    function deleteIt(entity) {
        KinveyRequester.deleteEntity(entity)
            .then(deleteSuccess)
            .catch(handleAjaxError);
        function deleteSuccess() {
            showCollectionView();
            showInfo('Entity deleted.');
        }
    }
    //----------------------
    function logout() {
        sessionStorage.clear();
        $('#loggedInUser').text("");
        showHideMenuLinks();
        showView('viewHome');
        showInfo('Logout successful.');
    }

    //-----Input forms-----------------------------------------------------------------//

    function login() {
        event.preventDefault();
        let username = $('#formLogin input[name=username]').val();
        let password = $('#formLogin input[name=passwd]').val();
        KinveyRequester.loginUser(username, password)
            .then(loginSuccess)
            .catch(handleAjaxError);

        function loginSuccess(userInfo) {
            saveAuthInSession(userInfo);
            showHideMenuLinks();
            showCollectionView();
            showInfo('Login successful.');
        }
    }
    //-------------------
    function register() {
        event.preventDefault();
        let username = $('#formRegister input[name=username]').val();
        let password = $('#formRegister input[name=passwd]').val();
        KinveyRequester.registerUser(username, password)
            .then(registerSuccess)
            .catch(handleAjaxError);

        function registerSuccess(userInfo) {
            saveAuthInSession(userInfo);
            showHideMenuLinks();
            showCollectionView();
            showInfo('User registration successful.');
        }
    }
    //------------------
    function create() {
        let title = $('#formCreateAd input[name=title]').val();
        let body = $('#formCreateAd textarea[name=description]').val();
        let author = sessionStorage.username;
        let date = $('#formCreateAd input[name=datePublished]').val();
        KinveyRequester.createEntity(title, body, author, date)
            .then(createEntitySuccess)
            .catch(handleAjaxError);
        function createEntitySuccess() {
            showCollectionView();
            showInfo('Entity created.');
        }
    }
    //-----------------
    function edit() {
        let entity = $('#formEditAd input[name=id]').val();
        console.log(entity);
        let title = $('#formEditAd input[name=title]').val();
        console.log(title);
        let body = $('#formEditAd textarea[name=description]').val();
        console.log(body);
        let author = sessionStorage.username;
        let date = $('#formEditAd input[name=datePublished]').val();
        KinveyRequester.editEntity(entity, title, body, author, date)
            .then(editEntitySuccess)
            .catch(handleAjaxError);
        function editEntitySuccess() {
            showCollectionView();
            showInfo('Entity edited.');
        }
    }

    //-----Save data in sessionStorage--------------------------------------------------//
    function saveAuthInSession(userInfo) {
        let userAuth = userInfo._kmd.authtoken;
        sessionStorage.setItem('authToken', userAuth);
        let userId = userInfo._id;
        sessionStorage.setItem('userID', userId);
        let username = userInfo.username;
        sessionStorage.setItem('username', username);
        $('#loggedInUser').text("Welcome, " + username + "!");
        $('#loggedInUser').show();
    }

    //-----Error and information messages--------------------------------------------------//
    function showInfo(message) {
        $('#infoBox').text(message);
        $('#infoBox').show();
        setTimeout(function() {
            $('#infoBox').fadeOut();
        }, 3000);
    }
    function handleAjaxError(response) {
        let errorMsg = JSON.stringify(response);
        if (response.readyState === 0)
            errorMsg = "Cannot connect due to network error.";
        if (response.responseJSON &&
            response.responseJSON.description)
            errorMsg = response.responseJSON.description;
        showError(errorMsg);
    }
    function showError(errorMsg) {
        $('#errorBox').text("Error: " + errorMsg);
        $('#errorBox').show();
    }
}