refactor: code cleanup — named constants, dedup, naming consistency, XML docs

src/PassKey.Core/Services/CardTypeDetector.cs

@@ -4,6 +4,34 @@ namespace PassKey.Core.Services;
 
 public static class CardTypeDetector
 {
+    /// <summary>
+    /// BIN (Bank Identification Number) / IIN prefix ranges used for card-type detection.
+    /// Sources: EMVCo IIN Registry; updated ranges as of 2024.
+    /// </summary>
+    private static class BinRanges
+    {
+        // MasterCard: standard range 51-55 is checked inline with a 2-digit prefix;
+        // the expanded range covers re-issued BINs introduced in 2017.
+        internal const int MasterCardExpandedStart = 2221;
+        internal const int MasterCardExpandedEnd   = 2720;
+
+        // Discover: 3-digit prefix range (644-649)
+        internal const int DiscoverRange3Start = 644;
+        internal const int DiscoverRange3End   = 649;
+
+        // Discover: 6-digit IIN range (co-branded UnionPay; 622126-622925)
+        internal const int DiscoverRange6Start = 622126;
+        internal const int DiscoverRange6End   = 622925;
+
+        // JCB: 4-digit prefix range (3528-3589)
+        internal const int JcbRangeStart = 3528;
+        internal const int JcbRangeEnd   = 3589;
+
+        // Diners Club Classic: 3-digit prefix range (300-305)
+        internal const int DinersRange3Start = 300;
+        internal const int DinersRange3End   = 305;
+    }
+
     /// <summary>
     /// Detects the card type from the card number using BIN prefix tables.
     /// </summary>
@@ -24,7 +52,7 @@ public static CardType Detect(string cardNumber)
         if (digits.StartsWith('4'))
             return CardType.Visa;
 
-        // MasterCard: 51-55 or 2221-2720
+        // MasterCard: 51-55 or expanded range 2221-2720
         if (digits.Length >= 2)
         {
             var prefix2 = int.Parse(digits[..2]);
@@ -34,7 +62,7 @@ public static CardType Detect(string cardNumber)
         if (digits.Length >= 4)
         {
             var prefix4 = int.Parse(digits[..4]);
-            if (prefix4 >= 2221 && prefix4 <= 2720)
+            if (prefix4 >= BinRanges.MasterCardExpandedStart && prefix4 <= BinRanges.MasterCardExpandedEnd)
                 return CardType.MasterCard;
         }
 
@@ -44,21 +72,21 @@ public static CardType Detect(string cardNumber)
         if (digits.Length >= 3)
         {
             var prefix3 = int.Parse(digits[..3]);
-            if (prefix3 >= 644 && prefix3 <= 649)
+            if (prefix3 >= BinRanges.DiscoverRange3Start && prefix3 <= BinRanges.DiscoverRange3End)
                 return CardType.Discover;
         }
         if (digits.Length >= 6)
         {
             var prefix6 = int.Parse(digits[..6]);
-            if (prefix6 >= 622126 && prefix6 <= 622925)
+            if (prefix6 >= BinRanges.DiscoverRange6Start && prefix6 <= BinRanges.DiscoverRange6End)
                 return CardType.Discover;
         }
 
         // JCB: 3528-3589
         if (digits.Length >= 4)
         {
             var prefix4 = int.Parse(digits[..4]);
-            if (prefix4 >= 3528 && prefix4 <= 3589)
+            if (prefix4 >= BinRanges.JcbRangeStart && prefix4 <= BinRanges.JcbRangeEnd)
                 return CardType.JCB;
         }
 
@@ -68,7 +96,7 @@ public static CardType Detect(string cardNumber)
         if (digits.Length >= 3)
         {
             var prefix3 = int.Parse(digits[..3]);
-            if (prefix3 >= 300 && prefix3 <= 305)
+            if (prefix3 >= BinRanges.DinersRange3Start && prefix3 <= BinRanges.DinersRange3End)
                 return CardType.DinersClub;
         }
 

src/PassKey.Core/Services/MergeService.cs

@@ -11,82 +11,56 @@ public ImportResult MergeInto(Vault target, Vault source, ImportMergeStrategy st
         ArgumentNullException.ThrowIfNull(target);
         ArgumentNullException.ThrowIfNull(source);
 
-        int pwImported = 0, cardImported = 0, idImported = 0, noteImported = 0;
-        int skipped = 0, overwritten = 0;
+        var (pwImported,   pwSkipped,   pwOverwritten)   = MergeCollection(target.Passwords,   source.Passwords,   strategy, ComputePasswordHash);
+        var (cardImported, cardSkipped, cardOverwritten) = MergeCollection(target.CreditCards, source.CreditCards, strategy, ComputeCardHash);
+        var (idImported,   idSkipped,   idOverwritten)   = MergeCollection(target.Identities,  source.Identities,  strategy, ComputeIdentityHash);
+        var (noteImported, noteSkipped, noteOverwritten) = MergeCollection(target.SecureNotes, source.SecureNotes, strategy, ComputeNoteHash);
 
-        // Build hash sets of existing entries
-        var existingPwHashes = BuildHashSet(target.Passwords, ComputePasswordHash);
-        var existingCardHashes = BuildHashSet(target.CreditCards, ComputeCardHash);
-        var existingIdHashes = BuildHashSet(target.Identities, ComputeIdentityHash);
-        var existingNoteHashes = BuildHashSet(target.SecureNotes, ComputeNoteHash);
+        target.LastModified = DateTime.UtcNow;
 
-        // Merge passwords
-        foreach (var entry in source.Passwords)
+        return new ImportResult
         {
-            var hash = ComputePasswordHash(entry);
-            var result = MergeEntry(target.Passwords, entry, hash, existingPwHashes, strategy, ComputePasswordHash);
-            switch (result)
-            {
-                case MergeAction.Imported: pwImported++; break;
-                case MergeAction.Skipped: skipped++; break;
-                case MergeAction.Overwritten: overwritten++; break;
-            }
-        }
+            PasswordsImported  = pwImported,
+            CardsImported      = cardImported,
+            IdentitiesImported = idImported,
+            NotesImported      = noteImported,
+            Skipped    = pwSkipped    + cardSkipped    + idSkipped    + noteSkipped,
+            Overwritten = pwOverwritten + cardOverwritten + idOverwritten + noteOverwritten
+        };
+    }
 
-        // Merge credit cards
-        foreach (var entry in source.CreditCards)
-        {
-            var hash = ComputeCardHash(entry);
-            var result = MergeEntry(target.CreditCards, entry, hash, existingCardHashes, strategy, ComputeCardHash);
-            switch (result)
-            {
-                case MergeAction.Imported: cardImported++; break;
-                case MergeAction.Skipped: skipped++; break;
-                case MergeAction.Overwritten: overwritten++; break;
-            }
-        }
+    private enum MergeAction { Imported, Skipped, Overwritten }
 
-        // Merge identities
-        foreach (var entry in source.Identities)
-        {
-            var hash = ComputeIdentityHash(entry);
-            var result = MergeEntry(target.Identities, entry, hash, existingIdHashes, strategy, ComputeIdentityHash);
-            switch (result)
-            {
-                case MergeAction.Imported: idImported++; break;
-                case MergeAction.Skipped: skipped++; break;
-                case MergeAction.Overwritten: overwritten++; break;
-            }
-        }
+    private const int NoteHashSnippetLength = 256;
+
+    /// <summary>
+    /// Merges all entries from <paramref name="sourceList"/> into <paramref name="targetList"/>
+    /// applying the given <paramref name="strategy"/> for duplicates.
+    /// Returns a tuple of (imported, skipped, overwritten) counts.
+    /// </summary>
+    private static (int imported, int skipped, int overwritten) MergeCollection<T>(
+        List<T> targetList,
+        List<T> sourceList,
+        ImportMergeStrategy strategy,
+        Func<T, string> hashFunc) where T : class
+    {
+        int imported = 0, skipped = 0, overwritten = 0;
+        var existingHashes = BuildHashSet(targetList, hashFunc);
 
-        // Merge secure notes
-        foreach (var entry in source.SecureNotes)
+        foreach (var entry in sourceList)
         {
-            var hash = ComputeNoteHash(entry);
-            var result = MergeEntry(target.SecureNotes, entry, hash, existingNoteHashes, strategy, ComputeNoteHash);
+            var hash = hashFunc(entry);
+            var result = MergeEntry(targetList, entry, hash, existingHashes, strategy, hashFunc);
             switch (result)
             {
-                case MergeAction.Imported: noteImported++; break;
-                case MergeAction.Skipped: skipped++; break;
+                case MergeAction.Imported:    imported++;    break;
+                case MergeAction.Skipped:     skipped++;     break;
                 case MergeAction.Overwritten: overwritten++; break;
             }
         }
-
-        target.LastModified = DateTime.UtcNow;
-
-        return new ImportResult
-        {
-            PasswordsImported = pwImported,
-            CardsImported = cardImported,
-            IdentitiesImported = idImported,
-            NotesImported = noteImported,
-            Skipped = skipped,
-            Overwritten = overwritten
-        };
+        return (imported, skipped, overwritten);
     }
 
-    private enum MergeAction { Imported, Skipped, Overwritten }
-
     private static MergeAction MergeEntry<T>(
         List<T> targetList, T entry, string hash,
         Dictionary<string, int> existingHashes,
@@ -165,8 +139,8 @@ internal static string ComputeIdentityHash(IdentityEntry entry)
 
     internal static string ComputeNoteHash(SecureNoteEntry entry)
     {
-        var contentSnippet = entry.Content.Length > 256
-            ? entry.Content[..256]
+        var contentSnippet = entry.Content.Length > NoteHashSnippetLength
+            ? entry.Content[..NoteHashSnippetLength]
             : entry.Content;
         var input = $"{entry.Title.ToLowerInvariant()}|{contentSnippet}";
         return ComputeSha256(input);

src/PassKey.Core/Services/PasswordGenerator.cs

@@ -10,11 +10,15 @@ public sealed class PasswordGenerator : IPasswordGenerator
     private const string Symbols = "!@#$%^&*()-_=+[]{}|;:',.<>?/~`";
     private const string AmbiguousChars = "0O1lI|";
 
+    private const int MinPasswordLength = 8;
+    private const int MaxPasswordLength = 128;
+
     public string Generate(PasswordGeneratorOptions options)
     {
         ArgumentNullException.ThrowIfNull(options);
-        if (options.Length < 8 || options.Length > 128)
-            throw new ArgumentOutOfRangeException(nameof(options), "Length must be between 8 and 128.");
+        if (options.Length < MinPasswordLength || options.Length > MaxPasswordLength)
+            throw new ArgumentOutOfRangeException(nameof(options),
+                $"Length must be between {MinPasswordLength} and {MaxPasswordLength}.");
 
         var charPool = BuildCharPool(options);
         if (charPool.Length == 0)

src/PassKey.Core/Services/PasswordStrengthAnalyzer.cs

@@ -104,6 +104,19 @@ private static bool ContainsCommonPattern(string password)
         return false;
     }
 
+    /// <summary>
+    /// Time conversion constants used when formatting the estimated crack-time string.
+    /// </summary>
+    private static class TimeConstants
+    {
+        internal const double SecondsPerMinute     = 60;
+        internal const double SecondsPerHour       = 3_600;        // 60 * 60
+        internal const double SecondsPerDay        = 86_400;       // 60 * 60 * 24
+        internal const double SecondsPerYear       = 31_536_000;   // 365 * 24 * 60 * 60
+        internal const double SecondsPerCentury    = SecondsPerYear * 100;
+        internal const double SecondsPerMillennium = SecondsPerYear * 1_000;
+    }
+
     private static string EstimateCrackTime(int length, bool hasUpper, bool hasLower, bool hasDigit, bool hasSymbol)
     {
         var charsetSize = 0;
@@ -121,12 +134,12 @@ private static string EstimateCrackTime(int length, bool hasUpper, bool hasLower
         return seconds switch
         {
             < 1 => "instant",
-            < 60 => "seconds",
-            < 3600 => $"{(int)(seconds / 60)} minutes",
-            < 86400 => $"{(int)(seconds / 3600)} hours",
-            < 31536000 => $"{(int)(seconds / 86400)} days",
-            < 31536000.0 * 100 => $"{(int)(seconds / 31536000)} years",
-            < 31536000.0 * 1000 => "centuries",
+            < TimeConstants.SecondsPerMinute     => "seconds",
+            < TimeConstants.SecondsPerHour       => $"{(int)(seconds / TimeConstants.SecondsPerMinute)} minutes",
+            < TimeConstants.SecondsPerDay        => $"{(int)(seconds / TimeConstants.SecondsPerHour)} hours",
+            < TimeConstants.SecondsPerYear       => $"{(int)(seconds / TimeConstants.SecondsPerDay)} days",
+            < TimeConstants.SecondsPerCentury    => $"{(int)(seconds / TimeConstants.SecondsPerYear)} years",
+            < TimeConstants.SecondsPerMillennium => "centuries",
             _ => "millennia"
         };
     }

src/PassKey.Desktop/Helpers/ListViewHelpers.cs

@@ -0,0 +1,36 @@
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+
+namespace PassKey.Desktop.Helpers;
+
+/// <summary>
+/// Shared UI helpers for list-view code-behind classes.
+/// Centralises boilerplate that would otherwise be duplicated across
+/// <c>PasswordsListView</c>, <c>CreditCardsListView</c>, <c>IdentitiesListView</c>
+/// and <c>SecureNotesListView</c>.
+/// </summary>
+internal static class ListViewHelpers
+{
+    /// <summary>
+    /// Opens <paramref name="tip"/> for 2 seconds, then closes it automatically
+    /// via a <see cref="DispatcherTimer"/>.
+    /// </summary>
+    /// <param name="tip">The <see cref="TeachingTip"/> to show (e.g. SavedTip).</param>
+    /// <param name="extraAction">
+    /// Optional action invoked immediately after opening the tip.
+    /// Used by <c>SecureNotesListView</c> to trigger the accessibility announcer.
+    /// </param>
+    internal static void ShowSavedToast(TeachingTip tip, Action? extraAction = null)
+    {
+        tip.IsOpen = true;
+        extraAction?.Invoke();
+
+        var timer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(2) };
+        timer.Tick += (s, _) =>
+        {
+            tip.IsOpen = false;
+            ((DispatcherTimer)s!).Stop();
+        };
+        timer.Start();
+    }
+}