function um_init() {
  $('.user-save-btn').click(um_user_save);
  $('#nutzerliste').click(um_user_list_click);
  $('#nutzerLoeschen').click(um_del_user);
  $('#nutzerNeu').click(um_new_user);
  $('#nutzerLoeschen').prop( "disabled", true );
  um_clear_user_form();
  um_apicall_get_user_list();
}

/* ----- user functions ------ */

function um_user_save() {
  var user = um_user_form_lesen();
  var kww = $('#kennwortw').val();
  if(user.pw != kww) {
    alert('Kennworte stimmen nicht ueberein.');
  } else {
    //alert('user-save ' + user.id);
    um_apicall_create_user(self.serialisieren(user));
  }
}

function um_del_user() {
  var users = [];
  $('#nutzerliste :selected').each(function(i, selected){
    users[i] = $(selected).text();
  });

  //alert('delete user ' + users[0]);
  var antwort = confirm("Wollen Sie den Nutzer " + users[0] + " loeschen?"); 
  if (antwort == true) {
    var user = new User(users[0], '-', '-', '-', '-');
    um_apicall_del_user(self.serialisieren(user));
  }  
}

function um_new_user() {
  alert('show form to enter new user');
}

/* ----------- ui interaction ------------ */

function um_user_list_click() {
  $('#nutzerLoeschen').prop( "disabled", false );
  /*
   var users = [];
   $('#nutzerliste :selected').each(function(i, selected){
     users[i] = $(selected).text();
   });
  */
   //alert(users[0]);
}


/* ------- ui i/o ------ */

function um_user_form_lesen() {
  var userId = $('#anmeldename').val();
  var kw = $('#kennwort').val();
  var user = new User(userId, kw, '-', '-', '-');
  return user;
}

function um_show_user_list(resp) {
  $("#nutzerliste").empty();
  var users = resp.List[0];
  for(var i = 1; i < users.List.length; i++) {
    var user = users.List[i];
    $("#nutzerliste").append('<option value=' + user.String + '>' + user.String + '</option>');
  }
  $('#nutzerLoeschen').prop( "disabled", true );
  //var user1 = users.List[1];
  //var username = user1.String;
  //alert(username);
}

function um_clear_user_form() {
  $('#anmeldename').val('');
  $('#kennwort').val('');
  $('#kennwortw').val('');
}

/* ---- api calls ----- */

function um_apicall_create_user(user) {
  var m = 'createUser';
  var u = '../svc/' + m;
  $.ajax({
    url: u,
    data: {
      p: user
    },
    type: "POST",
    dataType : "html",
    success: function( resp ) {
      //$('#fehler').html('Antwort: ' + resp);
      um_apicall_get_user_list();
      um_clear_user_form();
    },
    error: function( xhr, status, errorThrown ) {
      $('#fehler').html("Error: " + errorThrown + " Status: " + status);
    },
    complete: function( xhr, status ) {
      //alert( "The request is complete!" );
    }
  });      
}

function um_apicall_del_user(user) {
  var m = 'deleteUser';
  var u = '../svc/' + m;
  $.ajax({
    url: u,
    data: {
      p: user
    },
    type: "POST",
    dataType : "html",
    success: function( resp ) {
      um_apicall_get_user_list();
    },
    error: function( xhr, status, errorThrown ) {
      $('#fehler').html("Error: " + errorThrown + " Status: " + status);
    },
    complete: function( xhr, status ) {
      //alert( "The request is complete!" );
    }
  });      
}

function um_apicall_get_user_list() {
  var m = 'getUserNameList';
  var u = '../svc/' + m;
  $.ajax({
    url: u,
    type: "GET",
    dataType : "json",
    success: function( resp ) {
      um_show_user_list(resp);
    },
    error: function( xhr, status, errorThrown ) {
      $('#fehler').html("Error: " + errorThrown + " Status: " + status);
    },
    complete: function( xhr, status ) {
      //alert( "The request is complete!" );
    }
  });      
}

/* ----- Hilfsfunktionen ----- */

function serialisieren(obj) {
  return '{"' + obj.constructor.name + '":' + JSON.stringify(obj) + '}';
};

/* ----- Objekte ----- */

function User(i, p, fn, ln, em) {
  this.id = i;
  this.pw = p;
  this.firstName = fn;
  this.lastName = ln;
  this.email = em;
}