[Hosts]Warn about duplicated entries (#22606)

* find duplicated entries

* addressed PR feedback

Co-authored-by: Davide <25966642+davidegiacometti@users.noreply.github.com>

src/modules/Hosts/Hosts/Models/Entry.cs

@@ -35,6 +35,7 @@ namespace Hosts.Models
             {
                 SetProperty(ref _hosts, value);
                 OnPropertyChanged(nameof(Valid));
+                SplittedHosts = _hosts.Split(' ');
             }
         }
 
@@ -50,8 +51,13 @@ namespace Hosts.Models
         [ObservableProperty]
         private bool _pinging;
 
+        [ObservableProperty]
+        private bool _duplicate;
+
         public bool Valid => ValidationHelper.ValidHosts(_hosts) && (ValidationHelper.ValidIPv4(_address) || ValidationHelper.ValidIPv6(_address));
 
+        public string[] SplittedHosts { get; private set; }
+
         public Entry()
         {
         }

src/modules/Hosts/Hosts/Strings/en-us/Resources.resw

@@ -184,6 +184,9 @@
   <data name="DeleteDialogAreYouSure.Text" xml:space="preserve">
     <value>Are you sure you want to delete this entry?</value>
   </data>
+  <data name="DuplicateEntryIcon.[using:Microsoft.UI.Xaml.Controls]ToolTipService.ToolTip" xml:space="preserve">
+    <value>Duplicate entry</value>
+  </data>
   <data name="Entries.[using:Microsoft.UI.Xaml.Automation]AutomationProperties.Name" xml:space="preserve">
     <value>Entries</value>
   </data>
@@ -234,6 +237,10 @@
     <value>Ping</value>
     <comment>"Ping" refers to the command-line utility, do not loc</comment>
   </data>
+  <data name="PingIcon.[using:Microsoft.UI.Xaml.Controls]ToolTipService.ToolTip" xml:space="preserve">
+    <value>Ping response</value>
+    <comment>"Ping" refers to the command-line utility, do not loc</comment>
+  </data>
   <data name="Reload.Content" xml:space="preserve">
     <value>Reload</value>
   </data>
@@ -243,6 +250,9 @@
   <data name="SettingsBtn.[using:Microsoft.UI.Xaml.Controls]ToolTipService.ToolTip" xml:space="preserve">
     <value>Settings</value>
   </data>
+  <data name="ShowOnlyDuplicates.Header" xml:space="preserve">
+    <value>Show only duplicates</value>
+  </data>
   <data name="UpdateBtn" xml:space="preserve">
     <value>Update</value>
   </data>

src/modules/Hosts/Hosts/ViewModels/MainViewModel.cs

@@ -1,8 +1,9 @@
-// Copyright (c) Microsoft Corporation
+// Copyright (c) Microsoft Corporation
 // The Microsoft Corporation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
 using System.Threading.Tasks;
@@ -13,7 +14,6 @@ using CommunityToolkit.Mvvm.Input;
 using CommunityToolkit.WinUI;
 using Hosts.Helpers;
 using Hosts.Models;
-using Hosts.Settings;
 using Microsoft.UI.Dispatching;
 
 namespace Hosts.ViewModels
@@ -21,7 +21,6 @@ namespace Hosts.ViewModels
     public partial class MainViewModel : ObservableObject, IDisposable
     {
         private readonly IHostsService _hostsService;
-        private readonly IUserSettings _userSettings;
         private readonly DispatcherQueue _dispatcherQueue = DispatcherQueue.GetForCurrentThread();
         private bool _disposed;
 
@@ -34,6 +33,9 @@ namespace Hosts.ViewModels
         [ObservableProperty]
         private bool _fileChanged;
 
+        [ObservableProperty]
+        private bool _filtered;
+
         [ObservableProperty]
         private string _addressFilter;
 
@@ -44,50 +46,15 @@ namespace Hosts.ViewModels
         private string _commentFilter;
 
         [ObservableProperty]
-        private bool _filtered;
+        [NotifyPropertyChangedFor(nameof(Entries))]
+        private bool _showOnlyDuplicates;
 
         [ObservableProperty]
         private string _additionalLines;
 
         private ObservableCollection<Entry> _entries;
 
-        public ObservableCollection<Entry> Entries
+        public ObservableCollection<Entry> Entries => _filtered || _showOnlyDuplicates ? GetFilteredEntries() : _entries;
-        {
-            get
-            {
-                if (_filtered)
-                {
-                    var filter = _entries.AsEnumerable();
-
-                    if (!string.IsNullOrWhiteSpace(_addressFilter))
-                    {
-                        filter = filter.Where(e => e.Address.Contains(_addressFilter, StringComparison.OrdinalIgnoreCase));
-                    }
-
-                    if (!string.IsNullOrWhiteSpace(_hostsFilter))
-                    {
-                        filter = filter.Where(e => e.Hosts.Contains(_hostsFilter, StringComparison.OrdinalIgnoreCase));
-                    }
-
-                    if (!string.IsNullOrWhiteSpace(_commentFilter))
-                    {
-                        filter = filter.Where(e => e.Comment.Contains(_commentFilter, StringComparison.OrdinalIgnoreCase));
-                    }
-
-                    return new ObservableCollection<Entry>(filter);
-                }
-                else
-                {
-                    return _entries;
-                }
-            }
-
-            set
-            {
-                _entries = value;
-                OnPropertyChanged(nameof(Entries));
-            }
-        }
 
         public ICommand ReadHostsCommand => new RelayCommand(ReadHosts);
 
@@ -99,12 +66,9 @@ namespace Hosts.ViewModels
 
         public ICommand OpenHostsFileCommand => new RelayCommand(OpenHostsFile);
 
-        public MainViewModel(
+        public MainViewModel(IHostsService hostService)
-            IHostsService hostService,
-            IUserSettings userSettings)
         {
             _hostsService = hostService;
-            _userSettings = userSettings;
 
             _hostsService.FileChanged += (s, e) =>
             {
@@ -116,24 +80,35 @@ namespace Hosts.ViewModels
         {
             entry.PropertyChanged += Entry_PropertyChanged;
             _entries.Add(entry);
+
+            FindDuplicates(entry.Address, entry.SplittedHosts);
+            OnPropertyChanged(nameof(Entries));
         }
 
         public void Update(int index, Entry entry)
         {
-            var existingEntry = _entries.ElementAt(index);
+            var existingEntry = Entries.ElementAt(index);
+            var oldAddress = existingEntry.Address;
+            var oldHosts = existingEntry.SplittedHosts;
+
             existingEntry.Address = entry.Address;
             existingEntry.Comment = entry.Comment;
             existingEntry.Hosts = entry.Hosts;
             existingEntry.Active = entry.Active;
+
+            FindDuplicates(oldAddress, oldHosts);
+            FindDuplicates(entry.Address, entry.SplittedHosts);
+            OnPropertyChanged(nameof(Entries));
         }
 
         public void DeleteSelected()
         {
+            var address = Selected.Address;
+            var hosts = Selected.SplittedHosts;
             _entries.Remove(Selected);
-            if (Filtered)
+
-            {
+            FindDuplicates(address, hosts);
-                OnPropertyChanged(nameof(Entries));
+            OnPropertyChanged(nameof(Entries));
-            }
         }
 
         public void UpdateAdditionalLines(string lines)
@@ -157,7 +132,7 @@ namespace Hosts.ViewModels
 
                 await _dispatcherQueue.EnqueueAsync(() =>
                 {
-                    Entries = new ObservableCollection<Entry>(entries);
+                    _entries = new ObservableCollection<Entry>(entries);
 
                     foreach (var e in _entries)
                     {
@@ -165,17 +140,24 @@ namespace Hosts.ViewModels
                     }
 
                     _entries.CollectionChanged += Entries_CollectionChanged;
+                    OnPropertyChanged(nameof(Entries));
+                    FindDuplicates();
                 });
             });
         }
 
         public void ApplyFilters()
         {
-            if (_entries != null)
+            if (_entries == null)
             {
-                Filtered = !string.IsNullOrWhiteSpace(_addressFilter) || !string.IsNullOrWhiteSpace(_hostsFilter) || !string.IsNullOrWhiteSpace(_commentFilter);
+                return;
-                OnPropertyChanged(nameof(Entries));
             }
+
+            Filtered = !string.IsNullOrWhiteSpace(_addressFilter)
+                || !string.IsNullOrWhiteSpace(_hostsFilter)
+                || !string.IsNullOrWhiteSpace(_commentFilter);
+
+            OnPropertyChanged(nameof(Entries));
         }
 
         public void ClearFilters()
@@ -183,6 +165,7 @@ namespace Hosts.ViewModels
             AddressFilter = null;
             HostsFilter = null;
             CommentFilter = null;
+            ShowOnlyDuplicates = false;
         }
 
         public async Task PingSelectedAsync()
@@ -212,8 +195,10 @@ namespace Hosts.ViewModels
 
         private void Entry_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
         {
-            // Ping should't trigger a file save
+            // Ping and duplicate should't trigger a file save
-            if (e.PropertyName == nameof(Entry.Ping) || e.PropertyName == nameof(Entry.Pinging))
+            if (e.PropertyName == nameof(Entry.Ping)
+                || e.PropertyName == nameof(Entry.Pinging)
+                || e.PropertyName == nameof(Entry.Duplicate))
             {
                 return;
             }
@@ -234,6 +219,68 @@ namespace Hosts.ViewModels
             });
         }
 
+        private void FindDuplicates()
+        {
+            foreach (var entry in _entries)
+            {
+                SetDuplicate(entry);
+            }
+        }
+
+        private void FindDuplicates(string address, IEnumerable<string> hosts)
+        {
+            var entries = _entries.Where(e =>
+                string.Equals(e.Address, address, StringComparison.InvariantCultureIgnoreCase)
+                || hosts.Intersect(e.SplittedHosts, StringComparer.InvariantCultureIgnoreCase).Any());
+
+            foreach (var entry in entries)
+            {
+                SetDuplicate(entry);
+            }
+        }
+
+        private void SetDuplicate(Entry entry)
+        {
+            var hosts = entry.SplittedHosts;
+
+            entry.Duplicate = _entries.FirstOrDefault(e =>
+                e != entry
+                && (string.Equals(e.Address, entry.Address, StringComparison.InvariantCultureIgnoreCase)
+                || hosts.Intersect(e.SplittedHosts, StringComparer.InvariantCultureIgnoreCase).Any())) != null;
+        }
+
+        private ObservableCollection<Entry> GetFilteredEntries()
+        {
+            if (_entries == null)
+            {
+                return new ObservableCollection<Entry>();
+            }
+
+            var filter = _entries.AsEnumerable();
+
+            if (!string.IsNullOrWhiteSpace(_addressFilter))
+            {
+                filter = filter.Where(e => e.Address.Contains(_addressFilter, StringComparison.OrdinalIgnoreCase));
+            }
+
+            if (!string.IsNullOrWhiteSpace(_hostsFilter))
+            {
+                filter = filter.Where(e => e.Hosts.Contains(_hostsFilter, StringComparison.OrdinalIgnoreCase));
+            }
+
+            if (!string.IsNullOrWhiteSpace(_commentFilter))
+            {
+                filter = filter.Where(e => e.Comment.Contains(_commentFilter, StringComparison.OrdinalIgnoreCase));
+            }
+
+            if (_showOnlyDuplicates)
+            {
+                filter = filter.Where(e => e.Duplicate);
+            }
+
+            return new ObservableCollection<Entry>(filter);
+        }
+
         protected virtual void Dispose(bool disposing)
         {
             if (!_disposed)

src/modules/Hosts/Hosts/Views/MainPage.xaml

@@ -116,6 +116,9 @@
                                         </ic:EventTriggerBehavior>
                                     </i:Interaction.Behaviors>
                                 </AutoSuggestBox>
+                                <ToggleSwitch
+                                    x:Uid="ShowOnlyDuplicates"
+                                    IsOn="{x:Bind ViewModel.ShowOnlyDuplicates, Mode=TwoWay}" />
                                 <Button
                                     x:Uid="ClearFiltersBtn"
                                     Margin="0,6,0,0"
@@ -151,7 +154,6 @@
             </StackPanel>
         </Grid>
 
-
         <StackPanel
             Grid.Row="2"
             Orientation="Vertical"
@@ -205,6 +207,7 @@
                             <ColumnDefinition Width="*" />
                             <ColumnDefinition Width="Auto" />
                             <ColumnDefinition Width="Auto" />
+                            <ColumnDefinition Width="Auto" />
                         </Grid.ColumnDefinitions>
                         <FlyoutBase.AttachedFlyout>
                             <MenuFlyout>
@@ -254,6 +257,7 @@
                             Margin="0,0,8,0"
                             IsActive="{x:Bind Pinging, Mode=OneWay}" />
                         <FontIcon
+                            x:Uid="PingIcon"
                             x:Name="PingIcon"
                             Grid.Column="2"
                             Margin="0,0,8,0"
@@ -306,9 +310,18 @@
                                 </ic:DataTriggerBehavior>
                             </i:Interaction.Behaviors>
                         </FontIcon>
+                        <FontIcon
+                            x:Uid="DuplicateEntryIcon"
+                            Grid.Column="3"
+                            Margin="0,0,8,0"
+                            Foreground="{StaticResource SystemControlErrorTextForegroundBrush}"
+                            FontFamily="{ThemeResource SymbolThemeFontFamily}"
+                            FontSize="18"
+                            Glyph="&#xe7BA;"
+                            Visibility="{x:Bind Duplicate, Mode=OneWay, Converter={StaticResource BoolToVisibilityConverter}}" />
                         <ToggleSwitch
                             x:Uid="ActiveToggle"
-                            Grid.Column="3"
+                            Grid.Column="4"
                             Width="40"
                             MinWidth="0"
                             HorizontalAlignment="Right"
@@ -384,7 +397,6 @@
                 ScrollViewer.VerticalScrollBarVisibility="Visible"
                 ScrollViewer.VerticalScrollMode="Enabled"
                 TextWrapping="Wrap" />
-
         </ContentDialog>
     </Grid>
 </Page>