save progress

src/__Libraries/StellaOps.Canonicalization/Json/CanonicalJsonSerializer.cs

@@ -75,13 +75,55 @@ public sealed class StableDictionaryConverter<TKey, TValue> : JsonConverter<IDic
     public override void Write(Utf8JsonWriter writer, IDictionary<TKey, TValue> value, JsonSerializerOptions options)
     {
         writer.WriteStartObject();
-        foreach (var kvp in value.OrderBy(x => x.Key?.ToString(), StringComparer.Ordinal))
+        var ordered = value
+            .Select(kvp => new
+            {
+                Key = kvp.Key,
+                Value = kvp.Value,
+                RawKeyString = ConvertKeyToString(kvp.Key)
+            })
+            .Select(kvp => new
+            {
+                kvp.Key,
+                kvp.Value,
+                kvp.RawKeyString,
+                KeyString = ApplyKeyPolicy(kvp.RawKeyString, options)
+            })
+            .OrderBy(kvp => kvp.KeyString, StringComparer.Ordinal)
+            .ThenBy(kvp => kvp.RawKeyString, StringComparer.Ordinal);
+
+        foreach (var kvp in ordered)
         {
-            writer.WritePropertyName(kvp.Key?.ToString() ?? string.Empty);
+            writer.WritePropertyName(kvp.KeyString);
             JsonSerializer.Serialize(writer, kvp.Value, options);
         }
         writer.WriteEndObject();
     }
+
+    private static string ConvertKeyToString(TKey key)
+    {
+        if (key is null)
+        {
+            throw new ArgumentException("Dictionary key cannot be null.", nameof(key));
+        }
+
+        return key switch
+        {
+            string s => s,
+            IFormattable formattable => formattable.ToString(null, CultureInfo.InvariantCulture),
+            _ => Convert.ToString(key, CultureInfo.InvariantCulture)
+        } ?? string.Empty;
+    }
+
+    private static string ApplyKeyPolicy(string keyString, JsonSerializerOptions options)
+    {
+        if (options.DictionaryKeyPolicy is not null)
+        {
+            keyString = options.DictionaryKeyPolicy.ConvertName(keyString);
+        }
+
+        return keyString;
+    }
 }
 
 /// <summary>
@@ -90,7 +132,10 @@ public sealed class StableDictionaryConverter<TKey, TValue> : JsonConverter<IDic
 public sealed class Iso8601DateTimeConverter : JsonConverter<DateTimeOffset>
 {
     public override DateTimeOffset Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
-        => DateTimeOffset.Parse(reader.GetString()!, CultureInfo.InvariantCulture);
+        => DateTimeOffset.Parse(
+            reader.GetString() ?? throw new JsonException("DateTimeOffset value is null."),
+            CultureInfo.InvariantCulture,
+            DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal);
 
     public override void Write(Utf8JsonWriter writer, DateTimeOffset value, JsonSerializerOptions options)
         => writer.WriteStringValue(value.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ss.fffZ", CultureInfo.InvariantCulture));