function showVew(vewID) {
    $("main > section").hide();

    $('#' + vewID).show();
}
function showHideNavLinks() {
    let loggedIn = sessionStorage.authToken != null;
    if(loggedIn){
        $("#linkLogin").hide();
        $("#linkRegister").hide();
        $("#linkListBooks").show();/*TODO List of books*/
        $("#linkCreateBook").show();
        $("#linkLogout").show();
    }
    else {
        $("#linkLogin").show();
        $("#linkRegister").show();
        $("#linkListBooks").hide();
        $("#linkCreateBook").hide();
        $("#linkLogout").hide();

    }
}
function showHomeVew() {
    showVew('vewHome')
}
function showLoginVew() {
    showVew('vewLogin')
}
function showRegisterVew() {
    showVew('vewRegister')
}
function showListBooksVew() {
    showVew('vewListBooks')
}
function showCreateBookVew() {
    showVew('vewCreatedBooks')
}
function logout() {
    alert('logout');
    showVew('vewHome')
}

$(function () {
    $("#linkHome").click(showHomeVew);
    $("#linkLogin").click(showLoginVew);
    $("#linkRegister").click(showRegisterVew);
    $("#linkListBooks").click(showListBooksVew);
    $("#linkCreateBook").click(showCreateBookVew);
    $("#linkLogout").click(logout);

    $("#loginButton").click(login);
    $("#registerButton").click(register);
    $("#createBookButton").click(createBook);

    showHomeVew();
    showHideNavLinks();
});

/*
$("#formLogin").submit(function (e) {
    e.preventDefault(); login();
});
$("#formRegister").submit(function (e) { /!*!!!!!!!!!!*!/
    e.preventDefault(); register();
});
$("#formCreateBook").submit(function (e) {
    e.preventDefault(); createBook();
});*/


const kinveyBaseUrl = "https://baas.kinvey.com/";
const kinveyAppKey = "kid_SJOSvBYB";
const kinveyAppSecret = "0274d97941d7422e8954ba4fb3fefea0";



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

}
function showInfo(message) {
    $('#infoBox').text(message);
    $('#infoBox').show();
    setTimeout(function () {
        $('#infobox').fadeOut()}, 3000)
}
function showError(errorMsg) {
    $('#errorBox').text("Error: " + errorMsg);
    $('#errorBox').show();
}
$(function () {
    showHideNavLinks();
    showVew('viewHome');
})
$("#linkHome").click(showHomeVew());
$("#linkLogin").click(showLoginVew());
$("#linkRegister").click(showRegisterVew());
$("#linkListBooks").click(showListBooksVew());
$("#linkCreateBook").click(showCreateBookVew());
$("#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 login() {
    const kinveyLoginUrl = kinveyBaseUrl + "user/" + kinveyAppKey + "/login";
    const kinveyAuthHeaders = {
        'Authorization' : "Basic " + btoa(kinveyAppKey + ":" + kinveyAppSecret)
    };
    let userData = {
        username: $('#loginUser').val(),
        password: $('#userPass').val()
    };
    console.log("logna se");
    $.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);
    showHideNavLinks();
    showListBooksVew();
    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);
    showHideNavLinks();
    showListBooksVew();
    showInfo('User registration successful.')
}
function listBooks() {
    $('#books').empty();
    showView('vewListBooks');

    const kinveyBooksUrl = kinveyBaseUrl + "appdata/" + kinveyAppKey + "/books";
    const kinveyAuthHeaders = {'Authorization' : "Kinvey " + sessionStorage.getItem('authToken')};

    $.ajax({
        method: "GET",
        url: kinveyBooksUrl,
        headers: kinveyAuthHeaders,
        success: loadBooksSuccess,
        error: handleAjaxError
    })
}
function loadBooksSuccess(books) {
    showInfo('Book 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 of 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() {
    console.log("vlezna v function-a");
    const kinveyBooksUrl = kinveyBaseUrl + "appdata/" + kinveyAppKey + "/books";
    const kinveyAuthHeaders = {'Authorization' : "Kinvey " + 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(response) {
        listBooks();
        showInfo('Book created.');
    }
    console.log("suzdade kniga");
}
function logout() {
    sessionStorage.clear();
    showHideNavLinks();
    showVew('viewHome');
}