Add extension methods

src/NexusMods.MnemonicDB.Abstractions/Attributes/Float32Attribute.cs

@@ -0,0 +1,17 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds a float32 value.
+/// </summary>
+[PublicAPI]
+public sealed class Float32Attribute(string ns, string name) : ScalarAttribute<float, float, Float32Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override float ToLowLevel(float value) => value;
+
+    /// <inheritdoc />
+    protected override float FromLowLevel(float value, AttributeResolver resolver) => value;
+}

src/NexusMods.MnemonicDB.Abstractions/Attributes/Float64Attribute.cs

@@ -0,0 +1,17 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds a float64 value.
+/// </summary>
+[PublicAPI]
+public sealed class Float64Attribute(string ns, string name) : ScalarAttribute<double, double, Float64Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override double ToLowLevel(double value) => value;
+
+    /// <inheritdoc />
+    protected override double FromLowLevel(double value, AttributeResolver resolver) => value;
+}

src/NexusMods.MnemonicDB.Abstractions/Attributes/Int128Attribute.cs

@@ -0,0 +1,18 @@
+using System;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an int128 value.
+/// </summary>
+[PublicAPI]
+public sealed class Int128Attribute(string ns, string name) : ScalarAttribute<Int128, Int128, Int128Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override Int128 ToLowLevel(Int128 value) => value;
+
+    /// <inheritdoc />
+    protected override Int128 FromLowLevel(Int128 value, AttributeResolver resolver) => value;
+}

src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt128Attribute.cs

@@ -0,0 +1,18 @@
+using System;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an uint128 value.
+/// </summary>
+[PublicAPI]
+public sealed class UInt128Attribute(string ns, string name) : ScalarAttribute<UInt128, UInt128, UInt128Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override UInt128 ToLowLevel(UInt128 value) => value;
+
+    /// <inheritdoc />
+    protected override UInt128 FromLowLevel(UInt128 value, AttributeResolver resolver) => value;
+}

src/NexusMods.MnemonicDB.Abstractions/EntityExtensions.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Linq;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.BuiltInEntities;
+using NexusMods.MnemonicDB.Abstractions.Models;
+
+namespace NexusMods.MnemonicDB.Abstractions;
+
+/// <summary>
+/// Extension methods for entities.
+/// </summary>
+[PublicAPI]
+public static class EntityExtensions
+{
+    /// <summary>
+    /// Gets the timestamp of the transaction that created the model.
+    /// </summary>
+    public static DateTimeOffset GetCreatedAt<T>(this T model, DateTimeOffset defaultValue = default)
+        where T : IReadOnlyModel<T>
+    {
+        if (model.Count == 0) return defaultValue;
+        var minTx = model.Min(m => m.T);
+
+        var tx = new Transaction.ReadOnly(model.Db, EntityId.From(minTx.Value));
+        return Transaction.Timestamp.Get(tx);
+    }
+}

src/NexusMods.MnemonicDB.Abstractions/EntityId.cs

@@ -1,11 +1,15 @@
-using TransparentValueObjects;
+using System;
+using System.Globalization;
+using JetBrains.Annotations;
+using TransparentValueObjects;
 
 namespace NexusMods.MnemonicDB.Abstractions;
 
 /// <summary>
 ///     A unique identifier for an entity.
 /// </summary>
 [ValueObject<ulong>]
+[PublicAPI]
 public readonly partial struct EntityId : IAugmentWith<JsonAugment>
 {
     /// <summary>
@@ -38,4 +42,24 @@ public override string ToString()
     {
         return "EId:" + Value.ToString("X");
     }
+
+    /// <summary>
+    /// Tries to parse a hex string as an entity ID.
+    /// </summary>
+    public static bool TryParseFromHex(ReadOnlySpan<char> input, out EntityId id)
+    {
+        const string prefix = "EId:";
+
+        if (input.StartsWith(prefix))
+            input = input[prefix.Length..];
+
+        if (ulong.TryParse(input, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var result))
+        {
+            id = EntityId.From(result);
+            return true;
+        }
+
+        id = default;
+        return false;
+    }
 }