buxfixes

.gitignore

@@ -0,0 +1,11 @@
+# SQLite Datenbanken und Journal-Dateien
+*.db
+*.db-shm
+*.db-wal
+
+# Build-Artefakte
+bin/
+obj/
+*.user
+*.suo
+*.vs/

Components/Layout/MainLayout.razor

@@ -1,4 +1,9 @@
 @inherits LayoutComponentBase
+@inject AuthenticationStateProvider AuthStateProvider
+@inject NavigationManager Nav
+@inject timetracker.Data.UserNotificationService UserNotificationService
+@implements IDisposable
+@using System.Security.Claims
 
 <MudThemeProvider Theme="_theme" />
 <MudPopoverProvider />
@@ -29,6 +34,26 @@
 @code {
     private bool _drawerOpen = true;
 
+    protected override void OnInitialized()
+    {
+        UserNotificationService.OnUserDeleted += HandleUserDeleted;
+    }
+
+    private async Task HandleUserDeleted(int deletedUserId)
+    {
+        var state = await AuthStateProvider.GetAuthenticationStateAsync();
+        var idClaim = state.User.FindFirst(ClaimTypes.NameIdentifier)?.Value;
+        if (idClaim != null && int.TryParse(idClaim, out var myId) && myId == deletedUserId)
+        {
+            await InvokeAsync(() => Nav.NavigateTo("/auth/logout", forceLoad: true));
+        }
+    }
+
+    public void Dispose()
+    {
+        UserNotificationService.OnUserDeleted -= HandleUserDeleted;
+    }
+
     private readonly MudTheme _theme = new()
     {
         PaletteLight = new PaletteLight

Components/Layout/NavMenu.razor

@@ -1,10 +1,36 @@
-<MudNavMenu>
-    <MudText Typo="Typo.h6" Class="px-4 mt-4 mb-2">Navigation</MudText>
-    <MudDivider Class="mb-2" />
-    <MudNavLink Href="" Match="NavLinkMatch.All" Icon="@Icons.Material.Filled.CalendarMonth">Wochenübersicht</MudNavLink>
-    <MudNavLink Href="month" Icon="@Icons.Material.Filled.CalendarViewMonth">Monatsübersicht</MudNavLink>
-    <MudNavLink Href="feiertage" Icon="@Icons.Material.Filled.Celebration">Feiertage</MudNavLink>
-    <MudNavLink Href="urlaub-maximizer" Icon="@Icons.Material.Filled.AutoAwesome">Urlaubs-Maximizer</MudNavLink>
-    <MudNavLink Href="settings" Icon="@Icons.Material.Filled.Settings">Einstellungen</MudNavLink>
-</MudNavMenu>
-
+<div style="display:flex; flex-direction:column; height:100%;">
+    <MudNavMenu Style="flex:1">
+        <MudDivider Class="mb-2" />
+        <MudNavLink Href="" Match="NavLinkMatch.All" Icon="@Icons.Material.Filled.CalendarMonth">Wochenübersicht</MudNavLink>
+        <MudNavLink Href="month" Icon="@Icons.Material.Filled.CalendarViewMonth">Monatsübersicht</MudNavLink>
+        <MudNavLink Href="feiertage" Icon="@Icons.Material.Filled.Celebration">Feiertage</MudNavLink>
+        <MudNavLink Href="urlaub-maximizer" Icon="@Icons.Material.Filled.AutoAwesome">Urlaubs-Maximizer</MudNavLink>
+        <MudNavLink Href="settings" Icon="@Icons.Material.Filled.Settings">Einstellungen</MudNavLink>
+        <MudDivider Class="mt-2 mb-2" />
+        <AuthorizeView Policy="AdminOnly">
+            <MudNavLink Href="admin/users" Icon="@Icons.Material.Filled.AdminPanelSettings" IconColor="Color.Error">
+                Benutzerverwaltung
+            </MudNavLink>
+        </AuthorizeView>
+    </MudNavMenu>
+    <AuthorizeView>
+        <Authorized>
+            <MudDivider />
+            <MudStack Row="true" AlignItems="AlignItems.Center" Class="px-4 py-2" Spacing="1">
+                <MudIcon Icon="@Icons.Material.Filled.AccountCircle" Color="Color.Primary" Size="Size.Small" />
+                <MudText Typo="Typo.body2" Style="font-weight:600">@context.User.Identity?.Name</MudText>
+            </MudStack>
+            <MudNavMenu>
+                <MudNavLink Href="/auth/logout" Icon="@Icons.Material.Filled.Logout">Abmelden</MudNavLink>
+            </MudNavMenu>
+        </Authorized>
+    </AuthorizeView>
+    <MudTooltip Text="Changelog anzeigen" Placement="Placement.Top">
+        <MudNavMenu>
+            <MudNavLink Href="/changelog" Icon="@Icons.Material.Filled.NewReleases"
+                        Style="color: var(--mud-palette-text-disabled); font-size:0.75rem;">
+                Version 1.1
+            </MudNavLink>
+        </MudNavMenu>
+    </MudTooltip>
+</div>

Components/Pages/AdminUsers.razor

@@ -0,0 +1,176 @@
+@page "/admin/users"
+@rendermode InteractiveServer
+@attribute [Authorize(Policy = "AdminOnly")]
+@inject AuthService AuthService
+@inject ISnackbar Snackbar
+@inject AuthenticationStateProvider AuthStateProvider
+@inject timetracker.Data.UserNotificationService UserNotificationService
+@implements IDisposable
+
+<PageTitle>Benutzerverwaltung – Timetracker</PageTitle>
+
+@if (_loading)
+{
+    <MudStack AlignItems="AlignItems.Center" Class="mt-16" Spacing="3">
+        <MudProgressCircular Color="Color.Primary" Indeterminate="true" Size="Size.Large" />
+        <MudText Color="Color.Secondary">Lade Benutzer…</MudText>
+    </MudStack>
+}
+else
+{
+    <MudStack Spacing="4">
+
+        @* ── Header ── *@
+        <MudPaper Elevation="4" Class="pa-5 rounded-xl"
+                  Style="background: linear-gradient(135deg, #B71C1C 0%, #7F0000 100%); color:white;">
+            <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="3">
+                <MudIcon Icon="@Icons.Material.Filled.AdminPanelSettings" Style="color:white; font-size:2rem" />
+                <MudStack Spacing="0">
+                    <MudText Typo="Typo.h5" Style="color:white; font-weight:700">Benutzerverwaltung</MudText>
+                    <MudText Typo="Typo.caption" Style="color:rgba(255,255,255,0.72)">
+                        @_users.Count Benutzer registriert
+                    </MudText>
+                </MudStack>
+            </MudStack>
+        </MudPaper>
+
+        @* ── Tabelle ── *@
+        <MudCard Elevation="3" Class="rounded-xl">
+            <MudCardContent Class="pa-0">
+                <MudTable Items="_users" Hover="true" Striped="true" Dense="false"
+                          SortLabel="Sortieren">
+                    <HeaderContent>
+                        <MudTh><MudTableSortLabel SortBy="new Func<User, object>(u => u.Id)">ID</MudTableSortLabel></MudTh>
+                        <MudTh><MudTableSortLabel SortBy="new Func<User, object>(u => u.Username)" InitialDirection="SortDirection.Ascending">Benutzername</MudTableSortLabel></MudTh>
+                        <MudTh Style="text-align:right">Aktionen</MudTh>
+                    </HeaderContent>
+                    <RowTemplate>
+                        <MudTd>
+                            <MudText Typo="Typo.body2" Color="Color.Secondary">@context.Id</MudText>
+                        </MudTd>
+                        <MudTd>
+                            @if (_editUserId == context.Id)
+                            {
+                                <MudTextField @bind-Value="_editUsername"
+                                              Variant="Variant.Outlined"
+                                              Margin="Margin.Dense"
+                                              Immediate="true"
+                                              Style="max-width:220px"
+                                              OnKeyDown="@(async e => { if (e.Key == "Enter") await SaveRename(context); })" />
+                            }
+                            else
+                            {
+                                <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="2">
+                                    <MudIcon Icon="@Icons.Material.Filled.AccountCircle"
+                                             Color="@(context.Username == "marc" ? Color.Error : Color.Default)"
+                                             Size="Size.Small" />
+                                    <MudText Style="@(context.Username == "marc" ? "font-weight:700" : "")">
+                                        @context.Username
+                                    </MudText>
+                                    @if (context.Username == "marc")
+                                    {
+                                        <MudChip T="string" Size="Size.Small" Color="Color.Error" Variant="Variant.Outlined">Admin</MudChip>
+                                    }
+                                </MudStack>
+                            }
+                        </MudTd>
+                        <MudTd Style="text-align:right">
+                            @if (_editUserId == context.Id)
+                            {
+                                <MudIconButton Icon="@Icons.Material.Filled.Check"
+                                               Color="Color.Success"
+                                               Size="Size.Small"
+                                               OnClick="@(() => SaveRename(context))" />
+                                <MudIconButton Icon="@Icons.Material.Filled.Close"
+                                               Color="Color.Default"
+                                               Size="Size.Small"
+                                               OnClick="CancelEdit" />
+                            }
+                            else
+                            {
+                                <MudIconButton Icon="@Icons.Material.Filled.Edit"
+                                               Color="Color.Primary"
+                                               Size="Size.Small"
+                                               OnClick="@(() => StartEdit(context))" />
+                                @if (context.Username != "marc")
+                                {
+                                    <MudIconButton Icon="@Icons.Material.Filled.DeleteOutline"
+                                                   Color="Color.Error"
+                                                   Size="Size.Small"
+                                                   OnClick="@(() => DeleteUser(context))" />
+                                }
+                            }
+                        </MudTd>
+                    </RowTemplate>
+                    <NoRecordsContent>
+                        <MudText Color="Color.Secondary" Class="pa-4">Keine Benutzer gefunden.</MudText>
+                    </NoRecordsContent>
+                </MudTable>
+            </MudCardContent>
+        </MudCard>
+
+    </MudStack>
+}
+
+@code {
+    private List<User> _users = [];
+    private bool _loading = true;
+    private int? _editUserId;
+    private string _editUsername = "";
+
+    protected override async Task OnInitializedAsync()
+    {
+        var claim = (await AuthStateProvider.GetAuthenticationStateAsync())
+            .User.FindFirst(ClaimTypes.NameIdentifier);
+        if (claim == null) return;
+
+        UserNotificationService.OnUsersChanged += RefreshUsers;
+        _users = await AuthService.GetAllUsersAsync();
+        _loading = false;
+    }
+
+    private async Task RefreshUsers()
+    {
+        _users = await AuthService.GetAllUsersAsync();
+        await InvokeAsync(StateHasChanged);
+    }
+
+    public void Dispose()
+    {
+        UserNotificationService.OnUsersChanged -= RefreshUsers;
+    }
+
+    private void StartEdit(User user)
+    {
+        _editUserId = user.Id;
+        _editUsername = user.Username;
+    }
+
+    private void CancelEdit()
+    {
+        _editUserId = null;
+        _editUsername = "";
+    }
+
+    private async Task SaveRename(User user)
+    {
+        var trimmed = _editUsername.Trim();
+        var error = await AuthService.RenameUserAsync(user.Id, trimmed);
+        if (error != null)
+        {
+            Snackbar.Add(error, Severity.Error);
+            return;
+        }
+        user.Username = trimmed;
+        _editUserId = null;
+        _editUsername = "";
+        Snackbar.Add($"Benutzer umbenannt zu \"{trimmed}\".", Severity.Success);
+    }
+
+    private async Task DeleteUser(User user)
+    {
+        await AuthService.DeleteUserAsync(user.Id);
+        _users.Remove(user);
+        Snackbar.Add($"Benutzer \"{user.Username}\" gelöscht.", Severity.Info);
+    }
+}

Components/Pages/Changelog.razor

@@ -0,0 +1,92 @@
+@page "/changelog"
+@rendermode InteractiveServer
+@attribute [Authorize]
+
+<PageTitle>Changelog – Timetracker</PageTitle>
+
+<MudStack Spacing="4">
+
+    @* ── Header ── *@
+    <MudPaper Elevation="4" Class="pa-5 rounded-xl"
+              Style="background: linear-gradient(135deg, #3F51B5 0%, #1A237E 100%); color:white;">
+        <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="3">
+            <MudIcon Icon="@Icons.Material.Filled.NewReleases" Style="color:white; font-size:2rem" />
+            <MudStack Spacing="0">
+                <MudText Typo="Typo.h5" Style="color:white; font-weight:700">Changelog</MudText>
+                <MudText Typo="Typo.caption" Style="color:rgba(255,255,255,0.72)">Versionshistorie &amp; Änderungen</MudText>
+            </MudStack>
+        </MudStack>
+    </MudPaper>
+
+    @foreach (var release in _releases)
+    {
+        <MudCard Elevation="2" Class="rounded-xl">
+            <MudCardContent>
+                <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="2" Class="mb-3">
+                    <MudChip T="string" Color="@(release.IsLatest ? Color.Primary : Color.Default)"
+                             Variant="Variant.Filled" Size="Size.Medium" Style="font-weight:700">
+                        @release.Version
+                    </MudChip>
+                    @if (release.IsLatest)
+                    {
+                        <MudChip T="string" Color="Color.Success" Variant="Variant.Outlined" Size="Size.Small">
+                            Aktuell
+                        </MudChip>
+                    }
+                    <MudText Typo="Typo.body2" Color="Color.Secondary">@release.Date</MudText>
+                </MudStack>
+                <MudDivider Class="mb-3" />
+                <MudStack Spacing="1">
+                    @foreach (var entry in release.Entries)
+                    {
+                        <MudStack Row="true" AlignItems="AlignItems.Start" Spacing="2">
+                            <MudChip T="string" Color="@GetTagColor(entry.Tag)" Variant="Variant.Outlined"
+                                     Size="Size.Small" Style="min-width:72px; justify-content:center; font-size:0.7rem;">
+                                @entry.Tag
+                            </MudChip>
+                            <MudText Typo="Typo.body2" Style="padding-top:2px">@entry.Text</MudText>
+                        </MudStack>
+                    }
+                </MudStack>
+            </MudCardContent>
+        </MudCard>
+    }
+
+</MudStack>
+
+@code {
+    private record ChangeEntry(string Tag, string Text);
+    private record Release(string Version, string Date, bool IsLatest, List<ChangeEntry> Entries);
+
+    private static Color GetTagColor(string tag) => tag switch
+    {
+        "Neu"     => Color.Success,
+        "Fix"     => Color.Error,
+        "Upgrade" => Color.Info,
+        _         => Color.Default
+    };
+
+    private readonly List<Release> _releases =
+    [
+        new("1.1", "08.06.2026", true,
+        [
+            new("Neu",     "Versionsnummer in der Navbar mit Link zum Changelog"),
+            new("Neu",     "Changelog-Seite"),
+            new("Neu",     "Live-Aktualisierung der Benutzerliste bei neuer Registrierung"),
+            new("Neu",     "Automatisches Abmelden gelöschter Benutzer"),
+            new("Neu",     "Benutzernamen in der Benutzerverwaltung umbenennen"),
+            new("Upgrade", "Navbar: Benutzer und Abmelden-Button unten fixiert"),
+        ]),
+        new("1.0", "20.05.2026", false,
+        [
+            new("Neu", "Erste Version des Timetrackers"),
+            new("Neu", "Wochenübersicht mit Arbeitszeiten und Pausen"),
+            new("Neu", "Monatsübersicht"),
+            new("Neu", "Feiertage-Verwaltung"),
+            new("Neu", "Urlaubs-Maximizer"),
+            new("Neu", "Einstellungen"),
+            new("Neu", "Benutzerverwaltung für Admins"),
+            new("Neu", "Registrierung und Login"),
+        ]),
+    ];
+}

Components/Pages/Feiertage.razor

@@ -1,6 +1,9 @@
 @page "/feiertage"
 @rendermode InteractiveServer
+@attribute [Authorize]
 @inject HolidayService HolidayService
+@inject TimetrackerService TrackerService
+@inject AuthenticationStateProvider AuthStateProvider
 
 <PageTitle>Feiertage – Timetracker</PageTitle>
 
@@ -185,15 +188,25 @@ else
     private List<PublicHoliday> _holidays = [];
     private string _subLabel = "";
 
+    private int _userId;
+    private AppSettings _settings = new();
+
     protected override async Task OnInitializedAsync()
     {
+        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
+        var claim = authState.User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier);
+        if (claim != null)
+        {
+            _userId = int.Parse(claim.Value);
+            _settings = await TrackerService.GetSettingsAsync(_userId);
+        }
         await LoadHolidays();
         _loading = false;
     }
 
     private async Task LoadHolidays()
     {
-        _holidays = await HolidayService.GetHolidaysAsync(_year);
+        _holidays = await HolidayService.GetHolidaysAsync(_year, _settings.GermanState);
         var count = _holidays.Count;
         var past  = _holidays.Count(h => h.Date < DateOnly.FromDateTime(DateTime.Today));
         _subLabel = count == 0

Components/Pages/Home.razor

@@ -1,8 +1,10 @@
-@page "/"
+@page "/"
 @rendermode InteractiveServer
+@attribute [Authorize]
 @inject TimetrackerService TrackerService
 @inject HolidayService HolidayService
 @inject ISnackbar Snackbar
+@inject AuthenticationStateProvider AuthStateProvider
 
 <PageTitle>KW @_kw – Wochenübersicht – Timetracker</PageTitle>
 
@@ -332,6 +334,7 @@ else
     private static readonly System.Globalization.CultureInfo _deCulture = new("de-DE");
 
     private bool _loading = true;
+    private int _userId;
     private DateOnly _monday;
     private List<DayVm> _days = [];
     private AppSettings _settings = new();
@@ -349,10 +352,14 @@ else
 
     protected override async Task OnInitializedAsync()
     {
+        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
+        var claim = authState.User.FindFirst(ClaimTypes.NameIdentifier);
+        if (claim == null) return; // Prerender-Pass – Circuit noch nicht authentifiziert
+        _userId = int.Parse(claim.Value);
         _monday = GetMonday(DateOnly.FromDateTime(DateTime.Today));
-        _settings = await TrackerService.GetSettingsAsync();
+        _settings = await TrackerService.GetSettingsAsync(_userId);
         await LoadWeek();
-        _totalOvertime = await TrackerService.GetTotalOvertimeAsync(_settings);
+        _totalOvertime = await TrackerService.GetTotalOvertimeAsync(_userId, _settings);
         _loading = false;
     }
 
@@ -360,15 +367,15 @@ else
     {
         if (_monday.Year != _holidayYear)
         {
-            var list = await HolidayService.GetHolidaysAsync(_monday.Year);
+            var list = await HolidayService.GetHolidaysAsync(_monday.Year, _settings.GermanState);
             _holidays = list.ToDictionary(h => h.Date, h => h.Name);
             _holidayYear = _monday.Year;
         }
-        var dbDays = await TrackerService.GetWeekAsync(_monday);
+        var dbDays = await TrackerService.GetWeekAsync(_userId, _monday);
         _days = Enumerable.Range(0, 7).Select(i =>
         {
             var date = _monday.AddDays(i);
-            return DayVm.From(dbDays.FirstOrDefault(d => d.Date == date), date);
+            return DayVm.From(dbDays.FirstOrDefault(d => d.Date == date), date, _userId);
         }).ToList();
         BuildWeekLabels();
     }
@@ -421,7 +428,7 @@ else
     private async Task SaveDay(DayVm day)
     {
         await TrackerService.UpsertWorkDayAsync(day.ToWorkDay());
-        _totalOvertime = await TrackerService.GetTotalOvertimeAsync(_settings);
+        _totalOvertime = await TrackerService.GetTotalOvertimeAsync(_userId, _settings);
         BuildWeekLabels();
     }
 
@@ -486,6 +493,7 @@ else
     private sealed class DayVm
     {
         public int Id { get; set; }
+        public int UserId { get; set; }
         public DateOnly Date { get; set; }
         public TimeSpan? Start { get; set; }
         public TimeSpan? End { get; set; }
@@ -500,9 +508,10 @@ else
 
         public TimeSpan? NetWork => GrossWork.HasValue ? GrossWork.Value - TotalBreakTime : null;
 
-        public static DayVm From(WorkDay? wd, DateOnly date) => new()
+        public static DayVm From(WorkDay? wd, DateOnly date, int userId) => new()
         {
             Id = wd?.Id ?? 0,
+            UserId = wd?.UserId ?? userId,
             Date = date,
             Start = wd?.StartTime?.ToTimeSpan(),
             End = wd?.EndTime?.ToTimeSpan(),
@@ -517,6 +526,7 @@ else
         public WorkDay ToWorkDay() => new()
         {
             Id = Id,
+            UserId = UserId,
             Date = Date,
             StartTime = Start.HasValue ? TimeOnly.FromTimeSpan(Start.Value) : null,
             EndTime = End.HasValue ? TimeOnly.FromTimeSpan(End.Value) : null,

Components/Pages/Login.razor

@@ -0,0 +1,140 @@
+@page "/login"
+@attribute [AllowAnonymous]
+@inject NavigationManager Nav
+
+<PageTitle>Anmelden – Timetracker</PageTitle>
+
+<MudContainer MaxWidth="MaxWidth.Small" Class="mt-16">
+    <MudStack AlignItems="AlignItems.Center" Spacing="4">
+
+        @* ── Logo / Header ── *@
+        <MudStack AlignItems="AlignItems.Center" Spacing="1">
+            <MudIcon Icon="@Icons.Material.Filled.AccessTime"
+                     Style="font-size:4rem; color:#1565C0" />
+            <MudText Typo="Typo.h4" Style="font-weight:700; color:#1565C0">Timetracker</MudText>
+        </MudStack>
+
+        <MudPaper Elevation="4" Class="pa-6 rounded-xl" Style="width:100%">
+            @* ── Static Tab Navigation ── *@
+            <MudStack Row="true" Justify="Justify.Center" Class="mb-4">
+                <MudButton Href="/login"
+                           Variant="@(_activeTab == 0 ? Variant.Filled : Variant.Text)"
+                           Color="Color.Primary"
+                           Style="min-width: 120px; border-radius: 20px;">
+                    Anmelden
+                </MudButton>
+                <MudButton Href="/login?tab=register"
+                           Variant="@(_activeTab == 1 ? Variant.Filled : Variant.Text)"
+                           Color="Color.Primary"
+                           Style="min-width: 120px; border-radius: 20px;">
+                    Registrieren
+                </MudButton>
+            </MudStack>
+
+            <MudDivider Class="mb-6" />
+
+            @if (_activeTab == 0)
+            {
+                @* ── Login Form ── *@
+                <MudStack Spacing="3">
+                    @if (_error != null)
+                    {
+                        <MudAlert Severity="Severity.Error" Dense="true">@_error</MudAlert>
+                    }
+                    <form action="/auth/login" method="post">
+                        <MudStack Spacing="3">
+                            <MudTextField T="string"
+                                          Label="Benutzername"
+                                          Variant="Variant.Outlined"
+                                          Adornment="Adornment.Start"
+                                          AdornmentIcon="@Icons.Material.Filled.Person"
+                                          name="username"
+                                          Required="true"
+                                          AutoFocus="true" />
+                            <MudTextField T="string"
+                                          Label="Passwort"
+                                          Variant="Variant.Outlined"
+                                          Adornment="Adornment.Start"
+                                          AdornmentIcon="@Icons.Material.Filled.Lock"
+                                          InputType="InputType.Password"
+                                          name="password"
+                                          Required="true" />
+                            <MudButton ButtonType="ButtonType.Submit"
+                                       Variant="Variant.Filled"
+                                       Color="Color.Primary"
+                                       FullWidth="true"
+                                       Size="Size.Large"
+                                       StartIcon="@Icons.Material.Filled.Login"
+                                       Class="mt-2">
+                                Anmelden
+                            </MudButton>
+                        </MudStack>
+                    </form>
+                </MudStack>
+            }
+            else
+            {
+                @* ── Register Form ── *@
+                <MudStack Spacing="3">
+                    @if (_error != null)
+                    {
+                        <MudAlert Severity="Severity.Error" Dense="true">@_error</MudAlert>
+                    }
+                    <form action="/auth/register" method="post">
+                        <MudStack Spacing="3">
+                            <MudTextField T="string"
+                                          Label="Benutzername"
+                                          Variant="Variant.Outlined"
+                                          Adornment="Adornment.Start"
+                                          AdornmentIcon="@Icons.Material.Filled.Person"
+                                          name="username"
+                                          Required="true"
+                                          HelperText="Mindestens 3 Zeichen" />
+                            <MudTextField T="string"
+                                          Label="Passwort"
+                                          Variant="Variant.Outlined"
+                                          Adornment="Adornment.Start"
+                                          AdornmentIcon="@Icons.Material.Filled.Lock"
+                                          InputType="InputType.Password"
+                                          name="password"
+                                          Required="true"
+                                          HelperText="Mindestens 6 Zeichen" />
+                            <MudButton ButtonType="ButtonType.Submit"
+                                       Variant="Variant.Filled"
+                                       Color="Color.Secondary"
+                                       FullWidth="true"
+                                       Size="Size.Large"
+                                       StartIcon="@Icons.Material.Filled.PersonAdd"
+                                       Class="mt-2">
+                                Konto erstellen
+                            </MudButton>
+                        </MudStack>
+                    </form>
+                </MudStack>
+            }
+        </MudPaper>
+    </MudStack>
+</MudContainer>
+
+@code {
+    private int _activeTab = 0;
+    private string? _error;
+
+    [SupplyParameterFromQuery(Name = "error")]
+    public string? ErrorParam { get; set; }
+
+    [SupplyParameterFromQuery(Name = "tab")]
+    public string? TabParam { get; set; }
+
+    protected override void OnParametersSet()
+    {
+        _error = ErrorParam switch
+        {
+            "invalid" => "Benutzername oder Passwort falsch.",
+            not null  => Uri.UnescapeDataString(ErrorParam),
+            _         => null
+        };
+        _activeTab = TabParam == "register" ? 1 : 0;
+    }
+}
+

Components/Pages/Month.razor

@@ -1,7 +1,9 @@
 @page "/month"
 @rendermode InteractiveServer
+@attribute [Authorize]
 @inject TimetrackerService TrackerService
 @inject HolidayService HolidayService
+@inject AuthenticationStateProvider AuthStateProvider
 
 <PageTitle>@_deCulture.DateTimeFormat.GetMonthName(_month) @_year – Monatsübersicht – Timetracker</PageTitle>
 
@@ -150,6 +152,7 @@ else
     private static readonly System.Globalization.CultureInfo _deCulture = new("de-DE");
 
     private bool _loading = true;
+    private int _userId;
     private int _year = DateTime.Today.Year;
     private int _month = DateTime.Today.Month;
     private List<MonthDayVm> _days = [];
@@ -167,16 +170,20 @@ else
 
     protected override async Task OnInitializedAsync()
     {
-        _settings = await TrackerService.GetSettingsAsync();
+        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
+        var claim = authState.User.FindFirst(ClaimTypes.NameIdentifier);
+        if (claim == null) return;
+        _userId = int.Parse(claim.Value);
+        _settings = await TrackerService.GetSettingsAsync(_userId);
         await LoadMonth();
         _loading = false;
     }
 
     private async Task LoadMonth()
     {
-        var workDays = await TrackerService.GetMonthAsync(_year, _month);
-        var holidays = await HolidayService.GetHolidaysAsync(_year);
-        var vacations = await TrackerService.GetVacationDaysAsync(_year);
+        var workDays = await TrackerService.GetMonthAsync(_userId, _year, _month);
+        var holidays = await HolidayService.GetHolidaysAsync(_year, _settings.GermanState);
+        var vacations = await TrackerService.GetVacationDaysAsync(_userId, _year);
 
         var holidayMap = holidays.ToDictionary(h => h.Date, h => h.Name);
         var vacationSet = vacations.Select(v => v.Date).ToHashSet();

Components/Pages/Settings.razor

@@ -1,8 +1,10 @@
-@page "/settings"
+@page "/settings"
 @rendermode InteractiveServer
+@attribute [Authorize]
 @inject TimetrackerService TrackerService
 @inject HolidayService HolidayService
 @inject ISnackbar Snackbar
+@inject AuthenticationStateProvider AuthStateProvider
 
 <PageTitle>Einstellungen – Timetracker</PageTitle>
 
@@ -126,6 +128,65 @@ else
                 </MudCard>
             </MudItem>
 
+            @* ── Region & Feiertage ── *@
+            <MudItem xs="12" md="6">
+                <MudCard Elevation="3" Class="rounded-xl h-100">
+                    <MudCardHeader>
+                        <CardHeaderContent>
+                            <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="2">
+                                <MudIcon Icon="@Icons.Material.Filled.Public" Color="Color.Primary" />
+                                <MudText Typo="Typo.h6" Style="font-weight:600">Region & Feiertage</MudText>
+                            </MudStack>
+                        </CardHeaderContent>
+                    </MudCardHeader>
+                    <MudCardContent>
+                        <MudStack Spacing="4">
+                            <MudText Typo="Typo.body2" Color="Color.Secondary">
+                                Wähle dein Bundesland aus, um Bundesland-spezifische Feiertage zu berücksichtigen.
+                            </MudText>
+                            <MudSelect T="string" Label="Bundesland" Variant="Variant.Outlined" @bind-Value="_settings.GermanState" Clearable="true" Placeholder="Nur bundesweite Feiertage">
+                                @foreach (var state in GermanStates)
+                                {
+                                    <MudSelectItem Value="@state.Key">@state.Value</MudSelectItem>
+                                }
+                            </MudSelect>
+                        </MudStack>
+                    </MudCardContent>
+                </MudCard>
+            </MudItem>
+
+            @* ── Gleitzeitkonto ── *@
+            <MudItem xs="12" md="6">
+                <MudCard Elevation="3" Class="rounded-xl h-100">
+                    <MudCardHeader>
+                        <CardHeaderContent>
+                            <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="2">
+                                <MudIcon Icon="@Icons.Material.Filled.AccountBalance" Color="Color.Primary" />
+                                <MudText Typo="Typo.h6" Style="font-weight:600">Gleitzeitkonto-Start</MudText>
+                            </MudStack>
+                        </CardHeaderContent>
+                    </MudCardHeader>
+                    <MudCardContent>
+                        <MudStack Spacing="4">
+                            <MudDatePicker Label="Berechnungsstart"
+                                           @bind-Date="_flexStartDate"
+                                           HelperText="Gleitzeitberechnung läuft ab diesem Datum. Wenn leer, ab dem ersten Arbeitseintrag."
+                                           Variant="Variant.Outlined"
+                                           Clearable="true"
+                                           DateFormat="dd.MM.yyyy"
+                                           PickerVariant="PickerVariant.Inline" />
+
+                            <MudNumericField @bind-Value="_settings.FlexTimeStartingBalanceHours"
+                                             Label="Anfangsüberstunden (h)"
+                                             Variant="Variant.Outlined"
+                                             Step="0.5"
+                                             Format="0.##"
+                                             HelperText="Stufensaldo (Guthaben/Schulden) zum Berechnungsstart" />
+                        </MudStack>
+                    </MudCardContent>
+                </MudCard>
+            </MudItem>
+
         </MudGrid>
 
         @* ── Speichern-Button ── *@
@@ -375,6 +436,33 @@ else
     private static readonly System.Globalization.CultureInfo _deCulture = new("de-DE");
 
     private AppSettings? _settings;
+    private int _userId;
+    private DateTime? _flexStartDate
+    {
+        get => _settings?.FlexTimeStartDate?.ToDateTime(TimeOnly.MinValue);
+        set => _settings!.FlexTimeStartDate = value.HasValue ? DateOnly.FromDateTime(value.Value) : null;
+    }
+
+    private static readonly Dictionary<string, string> GermanStates = new()
+    {
+        { "DE-BW", "Baden-Württemberg" },
+        { "DE-BY", "Bayern" },
+        { "DE-BE", "Berlin" },
+        { "DE-BB", "Brandenburg" },
+        { "DE-HB", "Bremen" },
+        { "DE-HH", "Hamburg" },
+        { "DE-HE", "Hessen" },
+        { "DE-MV", "Mecklenburg-Vorpommern" },
+        { "DE-NI", "Niedersachsen" },
+        { "DE-NW", "Nordrhein-Westfalen" },
+        { "DE-RP", "Rheinland-Pfalz" },
+        { "DE-SL", "Saarland" },
+        { "DE-SN", "Sachsen" },
+        { "DE-ST", "Sachsen-Anhalt" },
+        { "DE-SH", "Schleswig-Holstein" },
+        { "DE-TH", "Thüringen" }
+    };
+
     private int _vacYear = DateTime.Today.Year;
     private List<VacationDay> _vacationDays = [];
     private DateTime? _newVacDateFrom;
@@ -402,14 +490,18 @@ else
 
     protected override async Task OnInitializedAsync()
     {
-        _settings = await TrackerService.GetSettingsAsync();
+        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
+        var claim = authState.User.FindFirst(ClaimTypes.NameIdentifier);
+        if (claim == null) return;
+        _userId = int.Parse(claim.Value);
+        _settings = await TrackerService.GetSettingsAsync(_userId);
         await LoadVacations();
-        _holHolidays = await HolidayService.GetHolidaysAsync(_holYear);
+        _holHolidays = await HolidayService.GetHolidaysAsync(_holYear, _settings.GermanState);
     }
 
     private async Task LoadVacations()
     {
-        _vacationDays = await TrackerService.GetVacationDaysAsync(_vacYear);
+        _vacationDays = await TrackerService.GetVacationDaysAsync(_userId, _vacYear);
     }
 
     private async Task ChangeYear(int delta)
@@ -422,6 +514,8 @@ else
     {
         if (_settings == null) return;
         await TrackerService.SaveSettingsAsync(_settings);
+        // Nach dem Speichern Feiertage neu laden, falls sich das Bundesland geändert hat
+        _holHolidays = await HolidayService.GetHolidaysAsync(_holYear, _settings.GermanState);
         Snackbar.Add("Einstellungen gespeichert", Severity.Success);
     }
 
@@ -438,7 +532,7 @@ else
         {
             if (_settings!.IsWorkDay(current.DayOfWeek))
             {
-                await TrackerService.AddVacationDayAsync(new VacationDay { Date = current, Note = note });
+                await TrackerService.AddVacationDayAsync(new VacationDay { UserId = _userId, Date = current, Note = note });
                 added++;
             }
             current = current.AddDays(1);
@@ -452,7 +546,7 @@ else
 
     private async Task RemoveVacation(int id)
     {
-        await TrackerService.RemoveVacationDayAsync(id);
+        await TrackerService.RemoveVacationDayAsync(_userId, id);
         await LoadVacations();
         Snackbar.Add("Urlaubstag entfernt", Severity.Info);
     }
@@ -461,14 +555,14 @@ else
     private async Task ChangeHolYear(int delta)
     {
         _holYear += delta;
-        _holHolidays = await HolidayService.GetHolidaysAsync(_holYear);
+        _holHolidays = await HolidayService.GetHolidaysAsync(_holYear, _settings?.GermanState);
     }
 
     private async Task FetchHolidays()
     {
         _fetchingHolidays = true;
         var (success, message) = await HolidayService.FetchAndStoreAsync(_holYear);
-        _holHolidays = await HolidayService.GetHolidaysAsync(_holYear);
+        _holHolidays = await HolidayService.GetHolidaysAsync(_holYear, _settings?.GermanState);
         _fetchingHolidays = false;
         Snackbar.Add(message, success ? Severity.Success : Severity.Error);
     }
@@ -476,7 +570,7 @@ else
     private async Task DeleteHoliday(int id)
     {
         await HolidayService.DeleteAsync(id);
-        _holHolidays = await HolidayService.GetHolidaysAsync(_holYear);
+        _holHolidays = await HolidayService.GetHolidaysAsync(_holYear, _settings?.GermanState);
         Snackbar.Add("Feiertag entfernt", Severity.Info);
     }
 

Components/Pages/UrlaubsMaximizer.razor

@@ -1,8 +1,10 @@
 @page "/urlaub-maximizer"
 @rendermode InteractiveServer
+@attribute [Authorize]
 @inject TimetrackerService TrackerService
 @inject HolidayService HolidayService
 @inject ISnackbar Snackbar
+@inject AuthenticationStateProvider AuthStateProvider
 
 <PageTitle>Urlaubs-Maximizer – Timetracker</PageTitle>
 
@@ -232,18 +234,23 @@ else
     private int _remainingDays;
     private List<Suggestion> _suggestions = [];
     private string _subLabel = "";
+    private int _userId;
 
     protected override async Task OnInitializedAsync()
     {
-        _settings = await TrackerService.GetSettingsAsync();
+        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
+        var claim = authState.User.FindFirst(ClaimTypes.NameIdentifier);
+        if (claim == null) return;
+        _userId = int.Parse(claim.Value);
+        _settings = await TrackerService.GetSettingsAsync(_userId);
         await LoadYear();
         _loading = false;
     }
 
     private async Task LoadYear()
     {
-        var holidays    = await HolidayService.GetHolidaysAsync(_year);
-        var vacations   = await TrackerService.GetVacationDaysAsync(_year);
+        var holidays    = await HolidayService.GetHolidaysAsync(_year, _settings.GermanState);
+        var vacations   = await TrackerService.GetVacationDaysAsync(_userId, _year);
         _holidays       = holidays.ToDictionary(h => h.Date, h => h.Name);
         _vacationSet    = vacations.Select(v => v.Date).ToHashSet();
         _remainingDays  = Math.Max(0, _settings.VacationDaysPerYear - vacations.Count);
@@ -262,7 +269,7 @@ else
     private async Task TakeSuggestion(Suggestion s)
     {
         foreach (var d in s.VacationDaysToTake.Where(d => !_vacationSet.Contains(d)))
-            await TrackerService.AddVacationDayAsync(new VacationDay { Date = d, Note = "Urlaubs-Maximizer" });
+            await TrackerService.AddVacationDayAsync(new VacationDay { UserId = _userId, Date = d, Note = "Urlaubs-Maximizer" });
         await LoadYear();
         var word = s.VacationDaysNeeded == 1 ? "Urlaubstag" : "Urlaubstage";
         Snackbar.Add($"{s.VacationDaysNeeded} {word} eingetragen – {s.TotalFreeDays} Tage frei!", Severity.Success);

Components/RedirectToLogin.razor

@@ -0,0 +1,9 @@
+@inject NavigationManager Nav
+
+@code {
+    protected override void OnInitialized()
+    {
+        var returnUrl = Uri.EscapeDataString(Nav.Uri);
+        Nav.NavigateTo($"/login?returnUrl={returnUrl}", forceLoad: true);
+    }
+}

Components/Routes.razor

@@ -2,7 +2,11 @@
 
 <Router AppAssembly="typeof(Program).Assembly" NotFoundPage="typeof(Pages.NotFound)">
     <Found Context="routeData">
-        <RouteView RouteData="routeData" DefaultLayout="typeof(Layout.MainLayout)" />
+        <AuthorizeRouteView RouteData="routeData" DefaultLayout="typeof(Layout.MainLayout)">
+            <NotAuthorized>
+                <RedirectToLogin />
+            </NotAuthorized>
+        </AuthorizeRouteView>
         <FocusOnNavigate RouteData="routeData" Selector="h1" />
     </Found>
 </Router>

Components/_Imports.razor

@@ -1,5 +1,8 @@
 @using System.Net.Http
 @using System.Net.Http.Json
+@using System.Security.Claims
+@using Microsoft.AspNetCore.Authorization
+@using Microsoft.AspNetCore.Components.Authorization
 @using Microsoft.AspNetCore.Components.Forms
 @using Microsoft.AspNetCore.Components.Routing
 @using Microsoft.AspNetCore.Components.Web

Data/AppSettings.cs

@@ -3,9 +3,13 @@ namespace timetracker.Data;
 public class AppSettings
 {
     public int Id { get; set; }
+    public int UserId { get; set; }
     public double DailyTargetHours { get; set; } = 7.5;
     public int MinimumBreakMinutes { get; set; } = 30;
     public int VacationDaysPerYear { get; set; } = 30;
+    public string? GermanState { get; set; }
+    public DateOnly? FlexTimeStartDate { get; set; }
+    public double FlexTimeStartingBalanceHours { get; set; } = 0.0;
 
     // Arbeitstage
     public bool WorkMonday { get; set; } = true;

Data/AuthService.cs

@@ -0,0 +1,96 @@
+using System.Security.Cryptography;
+using System.Text;
+using Microsoft.EntityFrameworkCore;
+
+namespace timetracker.Data;
+
+public class AuthService(IDbContextFactory<TimetrackerDbContext> factory, UserNotificationService notifier)
+{
+    public async Task<User?> LoginAsync(string username, string password)
+    {
+        await using var db = await factory.CreateDbContextAsync();
+        var user = await db.Users
+            .FirstOrDefaultAsync(u => u.Username == username);
+        if (user == null) return null;
+        return VerifyPassword(password, user.PasswordHash, user.PasswordSalt) ? user : null;
+    }
+
+    public async Task<List<User>> GetAllUsersAsync()
+    {
+        await using var db = await factory.CreateDbContextAsync();
+        return await db.Users
+            .OrderBy(u => u.Username)
+            .ToListAsync();
+    }
+
+    public async Task DeleteUserAsync(int userId)
+    {
+        await using var db = await factory.CreateDbContextAsync();
+        var user = await db.Users.FindAsync(userId);
+        if (user != null)
+        {
+            db.Users.Remove(user);
+            await db.SaveChangesAsync();
+            await notifier.NotifyUserDeletedAsync(userId);
+            await notifier.NotifyUsersChangedAsync();
+        }
+    }
+
+    public async Task<string?> RenameUserAsync(int userId, string newUsername)
+    {
+        if (string.IsNullOrWhiteSpace(newUsername) || newUsername.Length < 3)
+            return "Benutzername muss mindestens 3 Zeichen lang sein.";
+
+        await using var db = await factory.CreateDbContextAsync();
+        if (await db.Users.AnyAsync(u => u.Username == newUsername && u.Id != userId))
+            return "Benutzername bereits vergeben.";
+
+        var user = await db.Users.FindAsync(userId);
+        if (user == null) return "Benutzer nicht gefunden.";
+
+        user.Username = newUsername;
+        await db.SaveChangesAsync();
+        await notifier.NotifyUsersChangedAsync();
+        return null;
+    }
+
+    public async Task<(User? User, string? Error)> RegisterAsync(string username, string password)    {
+        if (string.IsNullOrWhiteSpace(username) || username.Length < 3)
+            return (null, "Benutzername muss mindestens 3 Zeichen lang sein.");
+        if (string.IsNullOrWhiteSpace(password) || password.Length < 6)
+            return (null, "Passwort muss mindestens 6 Zeichen lang sein.");
+
+        await using var db = await factory.CreateDbContextAsync();
+        if (await db.Users.AnyAsync(u => u.Username == username))
+            return (null, "Benutzername bereits vergeben.");
+
+        var (hash, salt) = HashPassword(password);
+        var user = new User { Username = username, PasswordHash = hash, PasswordSalt = salt };
+        db.Users.Add(user);
+        await db.SaveChangesAsync();
+        await notifier.NotifyUsersChangedAsync();
+        return (user, null);
+    }
+
+    private static (string hash, string salt) HashPassword(string password)
+    {
+        var saltBytes = RandomNumberGenerator.GetBytes(32);
+        var salt = Convert.ToBase64String(saltBytes);
+        var hash = ComputeHash(password, salt);
+        return (hash, salt);
+    }
+
+    private static bool VerifyPassword(string password, string hash, string salt)
+        => ComputeHash(password, salt) == hash;
+
+    private static string ComputeHash(string password, string salt)
+    {
+        var hash = Rfc2898DeriveBytes.Pbkdf2(
+            Encoding.UTF8.GetBytes(password),
+            Convert.FromBase64String(salt),
+            iterations: 200_000,
+            HashAlgorithmName.SHA256,
+            outputLength: 32);
+        return Convert.ToBase64String(hash);
+    }
+}

Data/HolidayService.cs

@@ -8,13 +8,22 @@ public class HolidayService(IDbContextFactory<TimetrackerDbContext> factory, Htt
 {
     private const string ApiUrl = "https://date.nager.at/api/v3/PublicHolidays/{0}/DE";
 
-    public async Task<List<PublicHoliday>> GetHolidaysAsync(int year)
+    public async Task<List<PublicHoliday>> GetHolidaysAsync(int year, string? stateCode = null)
     {
         await using var db = await factory.CreateDbContextAsync();
-        return await db.PublicHolidays
+        var holidays = await db.PublicHolidays
             .Where(h => h.Date.Year == year)
             .OrderBy(h => h.Date)
             .ToListAsync();
+
+        if (string.IsNullOrEmpty(stateCode))
+        {
+            // Default: return only global holidays (where Counties is null or empty)
+            return holidays.Where(h => string.IsNullOrEmpty(h.Counties)).ToList();
+        }
+
+        // Return global holidays OR holidays that match the user's state code
+        return holidays.Where(h => string.IsNullOrEmpty(h.Counties) || h.Counties.Split(',').Contains(stateCode)).ToList();
     }
 
     public async Task<(bool Success, string Message)> FetchAndStoreAsync(int year)
@@ -34,7 +43,8 @@ public class HolidayService(IDbContextFactory<TimetrackerDbContext> factory, Htt
                 .Select(h => new PublicHoliday
                 {
                     Date = DateOnly.Parse(h.Date),
-                    Name = h.LocalName
+                    Name = h.LocalName,
+                    Counties = h.Counties != null && h.Counties.Count > 0 ? string.Join(",", h.Counties) : null
                 }));
 
             await db.SaveChangesAsync();
@@ -64,5 +74,9 @@ public class HolidayService(IDbContextFactory<TimetrackerDbContext> factory, Htt
 
         [JsonPropertyName("localName")]
         public string LocalName { get; set; } = "";
+
+        [JsonPropertyName("counties")]
+        public List<string>? Counties { get; set; }
     }
 }
+

Data/Migrations/20260522081459_AddMultiUser.Designer.cs

@@ -0,0 +1,191 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using timetracker.Data;
+
+#nullable disable
+
+namespace timetracker.Data.Migrations
+{
+    [DbContext(typeof(TimetrackerDbContext))]
+    [Migration("20260522081459_AddMultiUser")]
+    partial class AddMultiUser
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder.HasAnnotation("ProductVersion", "10.0.8");
+
+            modelBuilder.Entity("timetracker.Data.AppSettings", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<double>("DailyTargetHours")
+                        .HasColumnType("REAL");
+
+                    b.Property<int>("MinimumBreakMinutes")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("VacationDaysPerYear")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkFriday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkMonday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkSaturday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkSunday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkThursday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkTuesday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkWednesday")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("AppSettings");
+                });
+
+            modelBuilder.Entity("timetracker.Data.BreakEntry", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<TimeOnly?>("EndTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("StartTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("WorkDayId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("WorkDayId");
+
+                    b.ToTable("BreakEntries");
+                });
+
+            modelBuilder.Entity("timetracker.Data.PublicHoliday", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("PublicHolidays");
+                });
+
+            modelBuilder.Entity("timetracker.Data.User", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("PasswordSalt")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Users");
+                });
+
+            modelBuilder.Entity("timetracker.Data.VacationDay", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Note")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("VacationDays");
+                });
+
+            modelBuilder.Entity("timetracker.Data.WorkDay", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("EndTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("StartTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("WorkDays");
+                });
+
+            modelBuilder.Entity("timetracker.Data.BreakEntry", b =>
+                {
+                    b.HasOne("timetracker.Data.WorkDay", "WorkDay")
+                        .WithMany("Breaks")
+                        .HasForeignKey("WorkDayId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("WorkDay");
+                });
+
+            modelBuilder.Entity("timetracker.Data.WorkDay", b =>
+                {
+                    b.Navigation("Breaks");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

Data/Migrations/20260522081459_AddMultiUser.cs

@@ -0,0 +1,69 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace timetracker.Data.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddMultiUser : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<int>(
+                name: "UserId",
+                table: "WorkDays",
+                type: "INTEGER",
+                nullable: false,
+                defaultValue: 0);
+
+            migrationBuilder.AddColumn<int>(
+                name: "UserId",
+                table: "VacationDays",
+                type: "INTEGER",
+                nullable: false,
+                defaultValue: 0);
+
+            migrationBuilder.AddColumn<int>(
+                name: "UserId",
+                table: "AppSettings",
+                type: "INTEGER",
+                nullable: false,
+                defaultValue: 0);
+
+            migrationBuilder.CreateTable(
+                name: "Users",
+                columns: table => new
+                {
+                    Id = table.Column<int>(type: "INTEGER", nullable: false)
+                        .Annotation("Sqlite:Autoincrement", true),
+                    Username = table.Column<string>(type: "TEXT", nullable: false),
+                    PasswordHash = table.Column<string>(type: "TEXT", nullable: false),
+                    PasswordSalt = table.Column<string>(type: "TEXT", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_Users", x => x.Id);
+                });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "Users");
+
+            migrationBuilder.DropColumn(
+                name: "UserId",
+                table: "WorkDays");
+
+            migrationBuilder.DropColumn(
+                name: "UserId",
+                table: "VacationDays");
+
+            migrationBuilder.DropColumn(
+                name: "UserId",
+                table: "AppSettings");
+        }
+    }
+}

Data/Migrations/20260607213215_AddFlexTimeAndHolidayState.Designer.cs

@@ -0,0 +1,203 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using timetracker.Data;
+
+#nullable disable
+
+namespace timetracker.Data.Migrations
+{
+    [DbContext(typeof(TimetrackerDbContext))]
+    [Migration("20260607213215_AddFlexTimeAndHolidayState")]
+    partial class AddFlexTimeAndHolidayState
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder.HasAnnotation("ProductVersion", "10.0.8");
+
+            modelBuilder.Entity("timetracker.Data.AppSettings", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<double>("DailyTargetHours")
+                        .HasColumnType("REAL");
+
+                    b.Property<DateOnly?>("FlexTimeStartDate")
+                        .HasColumnType("TEXT");
+
+                    b.Property<double>("FlexTimeStartingBalanceHours")
+                        .HasColumnType("REAL");
+
+                    b.Property<string>("GermanState")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("MinimumBreakMinutes")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("VacationDaysPerYear")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkFriday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkMonday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkSaturday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkSunday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkThursday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkTuesday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkWednesday")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("AppSettings");
+                });
+
+            modelBuilder.Entity("timetracker.Data.BreakEntry", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<TimeOnly?>("EndTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("StartTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("WorkDayId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("WorkDayId");
+
+                    b.ToTable("BreakEntries");
+                });
+
+            modelBuilder.Entity("timetracker.Data.PublicHoliday", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Counties")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("PublicHolidays");
+                });
+
+            modelBuilder.Entity("timetracker.Data.User", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("PasswordSalt")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Users");
+                });
+
+            modelBuilder.Entity("timetracker.Data.VacationDay", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Note")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("VacationDays");
+                });
+
+            modelBuilder.Entity("timetracker.Data.WorkDay", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("EndTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("StartTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("WorkDays");
+                });
+
+            modelBuilder.Entity("timetracker.Data.BreakEntry", b =>
+                {
+                    b.HasOne("timetracker.Data.WorkDay", "WorkDay")
+                        .WithMany("Breaks")
+                        .HasForeignKey("WorkDayId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("WorkDay");
+                });
+
+            modelBuilder.Entity("timetracker.Data.WorkDay", b =>
+                {
+                    b.Navigation("Breaks");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

Data/Migrations/20260607213215_AddFlexTimeAndHolidayState.cs

@@ -0,0 +1,60 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace timetracker.Data.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddFlexTimeAndHolidayState : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "Counties",
+                table: "PublicHolidays",
+                type: "TEXT",
+                nullable: true);
+
+            migrationBuilder.AddColumn<DateOnly>(
+                name: "FlexTimeStartDate",
+                table: "AppSettings",
+                type: "TEXT",
+                nullable: true);
+
+            migrationBuilder.AddColumn<double>(
+                name: "FlexTimeStartingBalanceHours",
+                table: "AppSettings",
+                type: "REAL",
+                nullable: false,
+                defaultValue: 0.0);
+
+            migrationBuilder.AddColumn<string>(
+                name: "GermanState",
+                table: "AppSettings",
+                type: "TEXT",
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "Counties",
+                table: "PublicHolidays");
+
+            migrationBuilder.DropColumn(
+                name: "FlexTimeStartDate",
+                table: "AppSettings");
+
+            migrationBuilder.DropColumn(
+                name: "FlexTimeStartingBalanceHours",
+                table: "AppSettings");
+
+            migrationBuilder.DropColumn(
+                name: "GermanState",
+                table: "AppSettings");
+        }
+    }
+}

Data/Migrations/TimetrackerDbContextModelSnapshot.cs

@@ -26,9 +26,21 @@ namespace timetracker.Data.Migrations
                     b.Property<double>("DailyTargetHours")
                         .HasColumnType("REAL");
 
+                    b.Property<DateOnly?>("FlexTimeStartDate")
+                        .HasColumnType("TEXT");
+
+                    b.Property<double>("FlexTimeStartingBalanceHours")
+                        .HasColumnType("REAL");
+
+                    b.Property<string>("GermanState")
+                        .HasColumnType("TEXT");
+
                     b.Property<int>("MinimumBreakMinutes")
                         .HasColumnType("INTEGER");
 
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
                     b.Property<int>("VacationDaysPerYear")
                         .HasColumnType("INTEGER");
 
@@ -58,24 +70,6 @@ namespace timetracker.Data.Migrations
                     b.ToTable("AppSettings");
                 });
 
-            modelBuilder.Entity("timetracker.Data.PublicHoliday", b =>
-                {
-                    b.Property<int>("Id")
-                        .ValueGeneratedOnAdd()
-                        .HasColumnType("INTEGER");
-
-                    b.Property<DateOnly>("Date")
-                        .HasColumnType("TEXT");
-
-                    b.Property<string>("Name")
-                        .IsRequired()
-                        .HasColumnType("TEXT");
-
-                    b.HasKey("Id");
-
-                    b.ToTable("PublicHolidays");
-                });
-
             modelBuilder.Entity("timetracker.Data.BreakEntry", b =>
                 {
                     b.Property<int>("Id")
@@ -98,6 +92,50 @@ namespace timetracker.Data.Migrations
                     b.ToTable("BreakEntries");
                 });
 
+            modelBuilder.Entity("timetracker.Data.PublicHoliday", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Counties")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("PublicHolidays");
+                });
+
+            modelBuilder.Entity("timetracker.Data.User", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("PasswordSalt")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Users");
+                });
+
             modelBuilder.Entity("timetracker.Data.VacationDay", b =>
                 {
                     b.Property<int>("Id")
@@ -110,6 +148,9 @@ namespace timetracker.Data.Migrations
                     b.Property<string>("Note")
                         .HasColumnType("TEXT");
 
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
                     b.HasKey("Id");
 
                     b.ToTable("VacationDays");
@@ -130,6 +171,9 @@ namespace timetracker.Data.Migrations
                     b.Property<TimeOnly?>("StartTime")
                         .HasColumnType("TEXT");
 
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
                     b.HasKey("Id");
 
                     b.ToTable("WorkDays");

Data/PublicHoliday.cs

@@ -5,4 +5,5 @@ public class PublicHoliday
     public int Id { get; set; }
     public DateOnly Date { get; set; }
     public string Name { get; set; } = "";
+    public string? Counties { get; set; }
 }

Data/TimetrackerDbContext.cs

@@ -4,6 +4,7 @@ namespace timetracker.Data;
 
 public class TimetrackerDbContext(DbContextOptions<TimetrackerDbContext> options) : DbContext(options)
 {
+    public DbSet<User> Users => Set<User>();
     public DbSet<WorkDay> WorkDays => Set<WorkDay>();
     public DbSet<BreakEntry> BreakEntries => Set<BreakEntry>();
     public DbSet<AppSettings> AppSettings => Set<AppSettings>();

Data/TimetrackerService.cs

@@ -4,12 +4,12 @@ namespace timetracker.Data;
 
 public class TimetrackerService(IDbContextFactory<TimetrackerDbContext> factory)
 {
-    public async Task<List<WorkDay>> GetWeekAsync(DateOnly monday)
+    public async Task<List<WorkDay>> GetWeekAsync(int userId, DateOnly monday)
     {
         await using var db = await factory.CreateDbContextAsync();
         return await db.WorkDays
             .Include(w => w.Breaks)
-            .Where(w => w.Date >= monday && w.Date < monday.AddDays(7))
+            .Where(w => w.UserId == userId && w.Date >= monday && w.Date < monday.AddDays(7))
             .OrderBy(w => w.Date)
             .ToListAsync();
     }
@@ -19,7 +19,7 @@ public class TimetrackerService(IDbContextFactory<TimetrackerDbContext> factory)
         await using var db = await factory.CreateDbContextAsync();
         var existing = await db.WorkDays
             .Include(w => w.Breaks)
-            .FirstOrDefaultAsync(w => w.Date == workDay.Date);
+            .FirstOrDefaultAsync(w => w.UserId == workDay.UserId && w.Date == workDay.Date);
 
         if (existing == null)
         {
@@ -45,17 +45,17 @@ public class TimetrackerService(IDbContextFactory<TimetrackerDbContext> factory)
         await db.SaveChangesAsync();
     }
 
-    public async Task<AppSettings> GetSettingsAsync()
+    public async Task<AppSettings> GetSettingsAsync(int userId)
     {
         await using var db = await factory.CreateDbContextAsync();
-        return await db.AppSettings.FindAsync(1) ?? new AppSettings { Id = 1 };
+        return await db.AppSettings.FirstOrDefaultAsync(s => s.UserId == userId)
+            ?? new AppSettings { UserId = userId };
     }
 
     public async Task SaveSettingsAsync(AppSettings settings)
     {
         await using var db = await factory.CreateDbContextAsync();
-        settings.Id = 1;
-        var existing = await db.AppSettings.FindAsync(1);
+        var existing = await db.AppSettings.FirstOrDefaultAsync(s => s.UserId == settings.UserId);
         if (existing == null)
             db.AppSettings.Add(settings);
         else
@@ -75,11 +75,11 @@ public class TimetrackerService(IDbContextFactory<TimetrackerDbContext> factory)
     }
 
     // ── Urlaub ────────────────────────────────────────────────────────────
-    public async Task<List<VacationDay>> GetVacationDaysAsync(int year)
+    public async Task<List<VacationDay>> GetVacationDaysAsync(int userId, int year)
     {
         await using var db = await factory.CreateDbContextAsync();
         return await db.VacationDays
-            .Where(v => v.Date.Year == year)
+            .Where(v => v.UserId == userId && v.Date.Year == year)
             .OrderBy(v => v.Date)
             .ToListAsync();
     }
@@ -87,7 +87,7 @@ public class TimetrackerService(IDbContextFactory<TimetrackerDbContext> factory)
     public async Task AddVacationDayAsync(VacationDay vacationDay)
     {
         await using var db = await factory.CreateDbContextAsync();
-        var exists = await db.VacationDays.AnyAsync(v => v.Date == vacationDay.Date);
+        var exists = await db.VacationDays.AnyAsync(v => v.UserId == vacationDay.UserId && v.Date == vacationDay.Date);
         if (!exists)
         {
             vacationDay.Id = 0;
@@ -96,10 +96,10 @@ public class TimetrackerService(IDbContextFactory<TimetrackerDbContext> factory)
         }
     }
 
-    public async Task RemoveVacationDayAsync(int id)
+    public async Task RemoveVacationDayAsync(int userId, int id)
     {
         await using var db = await factory.CreateDbContextAsync();
-        var v = await db.VacationDays.FindAsync(id);
+        var v = await db.VacationDays.FirstOrDefaultAsync(v => v.Id == id && v.UserId == userId);
         if (v != null)
         {
             db.VacationDays.Remove(v);
@@ -108,38 +108,90 @@ public class TimetrackerService(IDbContextFactory<TimetrackerDbContext> factory)
     }
 
     // ── Gleitzeitkonto ───────────────────────────────────────────────────
-    public async Task<TimeSpan> GetTotalOvertimeAsync(AppSettings settings)
+    public async Task<TimeSpan> GetTotalOvertimeAsync(int userId, AppSettings settings)
     {
         await using var db = await factory.CreateDbContextAsync();
-        var allDays = await db.WorkDays
+
+        // 1. Finde das Startdatum für die Berechnung
+        var firstDay = await db.WorkDays
+            .Where(w => w.UserId == userId)
+            .OrderBy(w => w.Date)
+            .Select(w => (DateOnly?)w.Date)
+            .FirstOrDefaultAsync();
+
+        if (firstDay == null && !settings.FlexTimeStartDate.HasValue)
+            return TimeSpan.FromHours(settings.FlexTimeStartingBalanceHours);
+
+        var startDate = settings.FlexTimeStartDate ?? firstDay!.Value;
+        var endDate = DateOnly.FromDateTime(DateTime.Today);
+
+        if (startDate > endDate)
+            return TimeSpan.FromHours(settings.FlexTimeStartingBalanceHours);
+
+        // 2. Lade alle erfassten Arbeitstage in diesem Zeitraum
+        var workDays = await db.WorkDays
             .Include(w => w.Breaks)
-            .Where(w => w.StartTime != null && w.EndTime != null)
+            .Where(w => w.UserId == userId && w.Date >= startDate && w.Date <= endDate)
+            .ToDictionaryAsync(w => w.Date);
+
+        // 3. Lade alle Feiertage in diesem Zeitraum
+        var holidaysList = await db.PublicHolidays
+            .Where(h => h.Date >= startDate && h.Date <= endDate)
             .ToListAsync();
 
-        var total = TimeSpan.Zero;
-        foreach (var wd in allDays)
+        var state = settings.GermanState;
+        var holidaySet = holidaysList
+            .Where(h => string.IsNullOrEmpty(h.Counties) || (!string.IsNullOrEmpty(state) && h.Counties.Split(',').Contains(state)))
+            .Select(h => h.Date)
+            .ToHashSet();
+
+        // 4. Lade alle Urlaubstage in diesem Zeitraum
+        var vacationSet = await db.VacationDays
+            .Where(v => v.UserId == userId && v.Date >= startDate && v.Date <= endDate)
+            .Select(v => v.Date)
+            .ToHashSetAsync();
+
+        double totalOvertimeHours = settings.FlexTimeStartingBalanceHours;
+
+        for (var date = startDate; date <= endDate; date = date.AddDays(1))
         {
-            if (!settings.IsWorkDay(wd.Date.DayOfWeek)) continue;
-            var gross = wd.EndTime!.Value.ToTimeSpan() - wd.StartTime!.Value.ToTimeSpan();
-            if (gross <= TimeSpan.Zero) continue;
-            var breakTotal = wd.Breaks
-                .Where(b => b.StartTime.HasValue && b.EndTime.HasValue && b.EndTime > b.StartTime)
-                .Aggregate(TimeSpan.Zero, (s, b) =>
-                    s + (b.EndTime!.Value.ToTimeSpan() - b.StartTime!.Value.ToTimeSpan()));
-            total += gross - breakTotal - TimeSpan.FromHours(settings.DailyTargetHours);
+            bool isWorkDay = settings.IsWorkDay(date.DayOfWeek);
+            bool isHoliday = holidaySet.Contains(date);
+            bool isVacation = vacationSet.Contains(date);
+
+            // Sollzeit gilt nur an regulären Arbeitstagen, die weder Feiertag noch Urlaub sind
+            double target = (isWorkDay && !isHoliday && !isVacation) ? settings.DailyTargetHours : 0.0;
+            double actual = 0.0;
+
+            if (workDays.TryGetValue(date, out var wd) && wd.StartTime != null && wd.EndTime != null)
+            {
+                var gross = wd.EndTime.Value.ToTimeSpan() - wd.StartTime.Value.ToTimeSpan();
+                if (gross > TimeSpan.Zero)
+                {
+                    var breakTotal = wd.Breaks
+                        .Where(b => b.StartTime.HasValue && b.EndTime.HasValue && b.EndTime > b.StartTime)
+                        .Aggregate(TimeSpan.Zero, (s, b) =>
+                            s + (b.EndTime!.Value.ToTimeSpan() - b.StartTime!.Value.ToTimeSpan()));
+                    actual = (gross - breakTotal).TotalHours;
+                    if (actual < 0) actual = 0.0;
+                }
+            }
+
+            totalOvertimeHours += (actual - target);
         }
-        return total;
+
+        return TimeSpan.FromHours(totalOvertimeHours);
     }
 
     // ── Monatsübersicht ───────────────────────────────────────────────────
-    public async Task<List<WorkDay>> GetMonthAsync(int year, int month)
+    public async Task<List<WorkDay>> GetMonthAsync(int userId, int year, int month)
     {
         await using var db = await factory.CreateDbContextAsync();
         var from = new DateOnly(year, month, 1);
         var to = from.AddMonths(1);
         return await db.WorkDays
             .Include(w => w.Breaks)
-            .Where(w => w.Date >= from && w.Date < to)
+            .Where(w => w.UserId == userId && w.Date >= from && w.Date < to)
             .OrderBy(w => w.Date)
             .ToListAsync();
     }

Data/User.cs

@@ -0,0 +1,9 @@
+namespace timetracker.Data;
+
+public class User
+{
+    public int Id { get; set; }
+    public string Username { get; set; } = "";
+    public string PasswordHash { get; set; } = "";
+    public string PasswordSalt { get; set; } = "";
+}

Data/UserNotificationService.cs

@@ -0,0 +1,19 @@
+namespace timetracker.Data;
+
+public class UserNotificationService
+{
+    public event Func<Task>? OnUsersChanged;
+    public event Func<int, Task>? OnUserDeleted;
+
+    public async Task NotifyUsersChangedAsync()
+    {
+        if (OnUsersChanged != null)
+            await OnUsersChanged.Invoke();
+    }
+
+    public async Task NotifyUserDeletedAsync(int userId)
+    {
+        if (OnUserDeleted != null)
+            await OnUserDeleted.Invoke(userId);
+    }
+}

Data/VacationDay.cs

@@ -3,6 +3,7 @@ namespace timetracker.Data;
 public class VacationDay
 {
     public int Id { get; set; }
+    public int UserId { get; set; }
     public DateOnly Date { get; set; }
     public string? Note { get; set; }
 }

Data/WorkDay.cs

@@ -3,6 +3,7 @@ namespace timetracker.Data;
 public class WorkDay
 {
     public int Id { get; set; }
+    public int UserId { get; set; }
     public DateOnly Date { get; set; }
     public TimeOnly? StartTime { get; set; }
     public TimeOnly? EndTime { get; set; }

Dockerfile

@@ -7,7 +7,7 @@ COPY timetracker.csproj ./
 RUN dotnet restore timetracker.csproj
 
 COPY . ./
-RUN dotnet publish -c Release -o /app/publish --no-restore
+RUN dotnet publish -c Release -o /app/publish
 
 # ── Runtime Stage ─────────────────────────────────────────────────────────────
 FROM mcr.microsoft.com/dotnet/aspnet:10.0 AS final
@@ -19,6 +19,7 @@ RUN mkdir -p /data
 
 ENV ASPNETCORE_HTTP_PORTS=8080
 ENV ASPNETCORE_ENVIRONMENT=Production
+ENV ASPNETCORE_FORWARDEDHEADERS_ENABLED=true
 ENV TIMETRACKER_DB_PATH=/data/timetracker.db
 ENV EnableHttpsRedirect=false
 

Program.cs

@@ -1,3 +1,7 @@
+using System.Security.Claims;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Authentication.Cookies;
+using Microsoft.AspNetCore.HttpOverrides;
 using Microsoft.EntityFrameworkCore;
 using MudBlazor.Services;
 using timetracker.Components;
@@ -5,6 +9,24 @@ using timetracker.Data;
 
 var builder = WebApplication.CreateBuilder(args);
 
+builder.Services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
+    .AddCookie(options =>
+    {
+        options.LoginPath = "/login";
+        options.LogoutPath = "/auth/logout";
+        options.ExpireTimeSpan = TimeSpan.FromDays(30);
+        options.SlidingExpiration = true;
+    });
+builder.Services.AddAuthorization(options =>
+{
+    options.AddPolicy("AdminOnly", policy =>
+        policy.RequireClaim(System.Security.Claims.ClaimTypes.Name, "marc"));
+});
+builder.Services.AddCascadingAuthenticationState();
+builder.Services.AddHttpContextAccessor();
+builder.Services.AddSingleton<timetracker.Data.UserNotificationService>();
+builder.Services.AddScoped<AuthService>();
+
 // Add services to the container.
 builder.Services.AddRazorComponents()
     .AddInteractiveServerComponents();
@@ -26,6 +48,14 @@ using (var scope = app.Services.CreateScope())
     await db.Database.MigrateAsync();
 }
 
+var forwardedHeadersOptions = new ForwardedHeadersOptions
+{
+    ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto
+};
+forwardedHeadersOptions.KnownProxies.Clear();
+forwardedHeadersOptions.KnownIPNetworks.Clear();
+app.UseForwardedHeaders(forwardedHeadersOptions);
+
 // Configure the HTTP request pipeline.
 if (!app.Environment.IsDevelopment())
 {
@@ -39,10 +69,64 @@ if (app.Configuration.GetValue("EnableHttpsRedirect", !app.Environment.IsDevelop
     app.UseHttpsRedirection();
 }
 
+// Statische Dateien (inkl. _framework/, _content/) vor Auth bedienen,
+// damit Blazor-JS und MudBlazor-CSS nie durch Auth-Middleware geblockt werden
+app.UseStaticFiles();
+
+app.UseAuthentication();
+app.UseAuthorization();
+
 app.UseAntiforgery();
 
 app.MapStaticAssets();
 app.MapRazorComponents<App>()
     .AddInteractiveServerRenderMode();
 
+// ── Auth-Endpoints ────────────────────────────────────────────────────────────
+app.MapPost("/auth/login", async (HttpContext ctx, AuthService authService) =>
+{
+    var form = await ctx.Request.ReadFormAsync();
+    var username = form["username"].ToString();
+    var password = form["password"].ToString();
+    var user = await authService.LoginAsync(username, password);
+    if (user == null)
+        return Results.Redirect("/login?error=invalid");
+
+    var claims = new[] {
+        new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
+        new Claim(ClaimTypes.Name, user.Username)
+    };
+    var identity = new ClaimsIdentity(claims, CookieAuthenticationDefaults.AuthenticationScheme);
+    await ctx.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme,
+        new ClaimsPrincipal(identity),
+        new AuthenticationProperties { IsPersistent = true });
+    return Results.Redirect("/");
+}).DisableAntiforgery();
+
+app.MapPost("/auth/register", async (HttpContext ctx, AuthService authService) =>
+{
+    var form = await ctx.Request.ReadFormAsync();
+    var username = form["username"].ToString();
+    var password = form["password"].ToString();
+    var (user, error) = await authService.RegisterAsync(username, password);
+    if (user == null)
+        return Results.Redirect($"/login?tab=register&error={Uri.EscapeDataString(error!)}");
+
+    var claims = new[] {
+        new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
+        new Claim(ClaimTypes.Name, user.Username)
+    };
+    var identity = new ClaimsIdentity(claims, CookieAuthenticationDefaults.AuthenticationScheme);
+    await ctx.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme,
+        new ClaimsPrincipal(identity),
+        new AuthenticationProperties { IsPersistent = true });
+    return Results.Redirect("/");
+}).DisableAntiforgery();
+
+app.MapGet("/auth/logout", async (HttpContext ctx) =>
+{
+    await ctx.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
+    return Results.Redirect("/login");
+});
+
 app.Run();

bin/Debug/net10.0/BuildHost-net472/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.exe.config

@@ -1,68 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<configuration>
-  <startup>
-    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />
-  </startup>
-  <runtime>
-    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-      <dependentAssembly>
-        <assemblyIdentity name="Microsoft.Build" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
-        <bindingRedirect oldVersion="0.0.0.0-15.1.0.0" newVersion="15.1.0.0" />
-      </dependentAssembly>
-    </assemblyBinding>
-    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-      <dependentAssembly>
-        <assemblyIdentity name="Microsoft.Build.Framework" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
-        <bindingRedirect oldVersion="0.0.0.0-15.1.0.0" newVersion="15.1.0.0" />
-      </dependentAssembly>
-    </assemblyBinding>
-    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-      <dependentAssembly>
-        <assemblyIdentity name="Microsoft.Build.Utilities.Core" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
-        <bindingRedirect oldVersion="0.0.0.0-15.1.0.0" newVersion="15.1.0.0" />
-      </dependentAssembly>
-    </assemblyBinding>
-    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-      <dependentAssembly>
-        <assemblyIdentity name="Microsoft.Build.Tasks.Core" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
-        <bindingRedirect oldVersion="0.0.0.0-15.1.0.0" newVersion="15.1.0.0" />
-      </dependentAssembly>
-    </assemblyBinding>
-    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-      <dependentAssembly>
-        <assemblyIdentity name="Microsoft.IO.Redist" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
-        <bindingRedirect oldVersion="0.0.0.0-6.1.0.0" newVersion="6.1.0.0" />
-      </dependentAssembly>
-    </assemblyBinding>
-    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-      <dependentAssembly>
-        <assemblyIdentity name="System.Buffers" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
-        <bindingRedirect oldVersion="0.0.0.0-4.0.4.0" newVersion="4.0.4.0" />
-      </dependentAssembly>
-    </assemblyBinding>
-    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-      <dependentAssembly>
-        <assemblyIdentity name="System.Collections.Immutable" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
-        <bindingRedirect oldVersion="0.0.0.0-9.0.0.0" newVersion="9.0.0.0" />
-      </dependentAssembly>
-    </assemblyBinding>
-    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-      <dependentAssembly>
-        <assemblyIdentity name="System.Memory" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
-        <bindingRedirect oldVersion="0.0.0.0-4.0.2.0" newVersion="4.0.2.0" />
-      </dependentAssembly>
-    </assemblyBinding>
-    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-      <dependentAssembly>
-        <assemblyIdentity name="System.Runtime.CompilerServices.Unsafe" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
-        <bindingRedirect oldVersion="0.0.0.0-6.0.1.0" newVersion="6.0.1.0" />
-      </dependentAssembly>
-    </assemblyBinding>
-    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-      <dependentAssembly>
-        <assemblyIdentity name="System.Threading.Tasks.Extensions" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
-        <bindingRedirect oldVersion="0.0.0.0-4.2.1.0" newVersion="4.2.1.0" />
-      </dependentAssembly>
-    </assemblyBinding>
-  </runtime>
-</configuration>

bin/Debug/net10.0/BuildHost-netcore/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.deps.json

@@ -1,171 +0,0 @@
-{
-  "runtimeTarget": {
-    "name": ".NETCoreApp,Version=v8.0",
-    "signature": ""
-  },
-  "compilationOptions": {},
-  "targets": {
-    ".NETCoreApp,Version=v8.0": {
-      "Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost/5.0.0-2.25567.12": {
-        "dependencies": {
-          "Microsoft.Build.Locator": "1.10.2",
-          "Newtonsoft.Json": "13.0.3",
-          "System.Collections.Immutable": "9.0.0",
-          "System.CommandLine": "2.0.0-rtm.25509.106"
-        },
-        "runtime": {
-          "Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.dll": {}
-        },
-        "resources": {
-          "cs/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "cs"
-          },
-          "de/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "de"
-          },
-          "es/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "es"
-          },
-          "fr/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "fr"
-          },
-          "it/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "it"
-          },
-          "ja/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "ja"
-          },
-          "ko/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "ko"
-          },
-          "pl/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "pl"
-          },
-          "pt-BR/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "pt-BR"
-          },
-          "ru/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "ru"
-          },
-          "tr/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "tr"
-          },
-          "zh-Hans/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "zh-Hans"
-          },
-          "zh-Hant/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.resources.dll": {
-            "locale": "zh-Hant"
-          }
-        }
-      },
-      "Microsoft.Build.Locator/1.10.2": {
-        "runtime": {
-          "lib/net8.0/Microsoft.Build.Locator.dll": {
-            "assemblyVersion": "1.0.0.0",
-            "fileVersion": "1.10.2.26959"
-          }
-        }
-      },
-      "Newtonsoft.Json/13.0.3": {
-        "runtime": {
-          "lib/net6.0/Newtonsoft.Json.dll": {
-            "assemblyVersion": "13.0.0.0",
-            "fileVersion": "13.0.3.27908"
-          }
-        }
-      },
-      "System.Collections.Immutable/9.0.0": {
-        "runtime": {
-          "lib/net8.0/System.Collections.Immutable.dll": {
-            "assemblyVersion": "9.0.0.0",
-            "fileVersion": "9.0.24.52809"
-          }
-        }
-      },
-      "System.CommandLine/2.0.0-rtm.25509.106": {
-        "runtime": {
-          "lib/net8.0/System.CommandLine.dll": {
-            "assemblyVersion": "2.0.0.0",
-            "fileVersion": "2.0.25.51006"
-          }
-        },
-        "resources": {
-          "lib/net8.0/cs/System.CommandLine.resources.dll": {
-            "locale": "cs"
-          },
-          "lib/net8.0/de/System.CommandLine.resources.dll": {
-            "locale": "de"
-          },
-          "lib/net8.0/es/System.CommandLine.resources.dll": {
-            "locale": "es"
-          },
-          "lib/net8.0/fr/System.CommandLine.resources.dll": {
-            "locale": "fr"
-          },
-          "lib/net8.0/it/System.CommandLine.resources.dll": {
-            "locale": "it"
-          },
-          "lib/net8.0/ja/System.CommandLine.resources.dll": {
-            "locale": "ja"
-          },
-          "lib/net8.0/ko/System.CommandLine.resources.dll": {
-            "locale": "ko"
-          },
-          "lib/net8.0/pl/System.CommandLine.resources.dll": {
-            "locale": "pl"
-          },
-          "lib/net8.0/pt-BR/System.CommandLine.resources.dll": {
-            "locale": "pt-BR"
-          },
-          "lib/net8.0/ru/System.CommandLine.resources.dll": {
-            "locale": "ru"
-          },
-          "lib/net8.0/tr/System.CommandLine.resources.dll": {
-            "locale": "tr"
-          },
-          "lib/net8.0/zh-Hans/System.CommandLine.resources.dll": {
-            "locale": "zh-Hans"
-          },
-          "lib/net8.0/zh-Hant/System.CommandLine.resources.dll": {
-            "locale": "zh-Hant"
-          }
-        }
-      }
-    }
-  },
-  "libraries": {
-    "Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost/5.0.0-2.25567.12": {
-      "type": "project",
-      "serviceable": false,
-      "sha512": ""
-    },
-    "Microsoft.Build.Locator/1.10.2": {
-      "type": "package",
-      "serviceable": true,
-      "sha512": "sha512-F+nLS7IpgtslyxNvtD6Jalnf5WU08lu8yfJBNQl3cbEF3AMUphs4t7nPuRYaaU8QZyGrqtVi7i73LhAe/yHx7A==",
-      "path": "microsoft.build.locator/1.10.2",
-      "hashPath": "microsoft.build.locator.1.10.2.nupkg.sha512"
-    },
-    "Newtonsoft.Json/13.0.3": {
-      "type": "package",
-      "serviceable": true,
-      "sha512": "sha512-HrC5BXdl00IP9zeV+0Z848QWPAoCr9P3bDEZguI+gkLcBKAOxix/tLEAAHC+UvDNPv4a2d18lOReHMOagPa+zQ==",
-      "path": "newtonsoft.json/13.0.3",
-      "hashPath": "newtonsoft.json.13.0.3.nupkg.sha512"
-    },
-    "System.Collections.Immutable/9.0.0": {
-      "type": "package",
-      "serviceable": true,
-      "sha512": "sha512-QhkXUl2gNrQtvPmtBTQHb0YsUrDiDQ2QS09YbtTTiSjGcf7NBqtYbrG/BE06zcBPCKEwQGzIv13IVdXNOSub2w==",
-      "path": "system.collections.immutable/9.0.0",
-      "hashPath": "system.collections.immutable.9.0.0.nupkg.sha512"
-    },
-    "System.CommandLine/2.0.0-rtm.25509.106": {
-      "type": "package",
-      "serviceable": true,
-      "sha512": "sha512-IdCQOFNHQfK0hu3tzWOHFJLMaiEOR/4OynmOh+IfukrTIsCR4TTDm7lpuXQyMZ0eRfIyUcz06gHGJNlILAq/6A==",
-      "path": "system.commandline/2.0.0-rtm.25509.106",
-      "hashPath": "system.commandline.2.0.0-rtm.25509.106.nupkg.sha512"
-    }
-  }
-}

bin/Debug/net10.0/BuildHost-netcore/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.runtimeconfig.json

@@ -1,14 +0,0 @@
-{
-  "runtimeOptions": {
-    "tfm": "net8.0",
-    "framework": {
-      "name": "Microsoft.NETCore.App",
-      "version": "8.0.0"
-    },
-    "rollForward": "Major",
-    "configProperties": {
-      "System.Reflection.Metadata.MetadataUpdater.IsSupported": false,
-      "System.Runtime.Serialization.EnableUnsafeBinaryFormatterSerialization": false
-    }
-  }
-}