const KinveyBaseUrl = "https://baas.kinvey.com/";
const KinveyAppKey = "kid_S1Jz5itH";
const KinveyAppSecret = "66335d68729e441fbf3f3d0cc1dc0fea";

function showView(viewName) {
    $('main > section').hide();

    $('#' = viewName).show();
}

function showHideMenuLinks() {
    $("#linkHome").show();
    if(sessionStorage.getItem('authToken') == null) {
        $('#linkLogin').show();
        $('#linkRegister').show();
        $('#linkListBooks').hide();
        $('#linkCreateBooks').hide();
        $('#linkLogout').hide();
    } else {
        $('#linkLogin').hide();
        $('#linkRegister').hide();
        $('#linkListBooks').show();
        $('#linkCreateBooks').show();
        $('#linkLogout').show();
    }
}

function showInfo(message) {
  $('#infoBox').text(message);
  $('#infoBox').show();
  setTimeout(function () { $('#infoBox').fadeOut() }, 3000);
}

function showError(errorMsg) {
    $('#errorBox').text("Error:" + errorMsg);
    $('#errorBox').show();
}

$(function () {
    showHideMenuLinks();
    showView('viewHome');

    $('#linkHome').click(showHomeView);
    $('#linkLogin').click(showLoginView);
    $('#linkRegister').click(showRegisterView);
    $('#linkListBooks').click(listBooks);
    $('#linkCreateBooks').click(showCreateBooks);
    $('#linkLogout').click(logout);

    $('$formLogin').submit(function (e) {
        e.preventDefault(); login();
    });
    $('formRegister').submit(function (e) {
        e.preventDefault(); register();
    });
    $('formCreateBook').submit(function (e) {
        e.preventDefault(); createBook();
    });

$(document).on({
    ajaxStart: function() { $('#loadingBox').show()},
    ajaxStop: function() { $('#loadingBox').hide()}
    });
});

function showHomeView () {
    showView('viewHome');
}
function showLoginView() {
    showView('viewLogin');
}

function login() {
    const kinveyLoginUrl = KinveyBaseUrl + "user/" + KinveyAppKey + "/login";
    const kinveyAuthHeaders = {
        'Authorization': "Basic" + btoa(KinveyAppKey + ":" + KinveyAppSecret)
    };
    let userData = {
        username: $("#loginUser").val(),
        password: $('#loginPassword').val()
    };
    $.ajax ({
        method: "POST",
        url: kinveyLoginUrl,
        headers: kinveyAuthHeaders,
        data: userData,
        success: loginSuccess,
        error: handleAjaxError
    });

    function loginSuccess (response) {
        let userAuth = response._kmd.authtoken;
        sessionStorage.setItem('authToken',userAuth);
        showHideMenuLinks();
        listBooks();
        showInfo('Login successful.');
    }
}

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 showRegisterView() {
    showView('viewRegister');
}

function register() {
    const kinveyRegisterUrl = KinveyBaseUrl + "user/" + KinveyAppKey + "/";
    const kinveyAuthHeaders = {
        'Authorization': "Basic" + btoa(KinveyAppKey + ":" + KinveyAppSecret)
    };

    let userData = {
        username: $('#registerUser').val(),
        password: $('#registerPass').val()
    };
    $.ajax({
        method: "POST",
        url: kinveyRegisterUrl,
        headers: kinveyAuthHeaders,
        data: userData,
        success: registerSuccess,
        error: handleAjaxError
    });

    function registerSuccess(response) {
        let userAuth = response._kmd.authtoken;
        sessionStorage.setItem('authToken',userAuth);
        showHideMenuLinks();
        listBooks();
        showInfo('User registration successful.');
    }
}

function listBooks() {
    $('#books').empty();
    showView('viewBooks');
    const kinveyBooksUrl = KinveyBaseUrl + "/appdata" + KinveyAppKey + "/books";
    const kinveyAuthHeaders = {
        'Authorization': "Basic" + sessionStorage.getItem('authToken'),
    };
    $.ajax({
       method: "GET",
       URL: kinveyBooksUrl,
       headers: kinveyAuthHeaders,
       success: loadBooksSuccess,
       error: handleAjaxError
    });

    function loadBooksSuccess() {
        showInfo('Books Loaded.');
        if(books.length == 0) {
            $('#books').text('No books in the library.');
        }
        else {
            let booksTable = $('<table>')
                .append($('<tr>').append(
                '<th>Title</th>',
                '<th>Author</th>',
                '<th>Description</th>')
        );
            for (let book in books) {
                booksTable.append($('<tr>').append(
                    $('<td>').text(book.title),
                    $('<td>').text(book.author),
                    $('<td>').text(book.description))
                );
            }
            $('#books').append(booksTable);
        }
    }
}

function showCreateBookView () {
    showView('viewCreateBook');
}

function createBook() {
    const kinveyBooksUrl = KinveyBaseUrl + "/appdata" + KinveyAppKey + "/books";
    const kinveyAuthHeaders = {
        'Authorization': "Basic" + sessionStorage.getItem('authToken'),
    };
    let bookData = {
        title: $('#bookTitle').val(),
        author: $('#bookAuthor').val(),
        description: $('#bookDescription').val()
    };
    $.ajax({
        method: "POST",
        url: kinveyBooksUrl,
        headers: kinveyAuthHeaders,
        data: bookData,
        success: createBookSuccess,
        error: handleAjaxError
    });

    function createBookSuccess() {
        listBooks();
        showInfo('Nook created.')
;    }
}

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