feat: add BaseDbContext, non-generic IEntity, fix Entity constructor

- add non-generic IEntity with Created/Updated only
- IEntity<TId> now extends IEntity
- remove Created = DateTimeOffset.UtcNow from Entity constructor
- add BaseDbContext with ApplyTimestamps, UtcValueConverter, DeleteBehavior.Restrict
- add UnexpectedEntityStateException
- add HrynCo.Common dependency to HrynCo.DAL.EF

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

HrynCo.DAL.EF/Converters/UtcValueConverter.cs

@@ -0,0 +1,6 @@
+namespace HrynCo.DAL.EF.Converters;
+
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+internal class UtcValueConverter()
+    : ValueConverter<DateTime, DateTime>(v => v, v => DateTime.SpecifyKind(v, DateTimeKind.Utc));

HrynCo.DAL.EF/Core/BaseDbContext.cs

@@ -0,0 +1,74 @@
+namespace HrynCo.DAL.EF.Core;
+
+using HrynCo.Common;
+using HrynCo.DAL.Abstract.Entities;
+using HrynCo.DAL.EF.Converters;
+using HrynCo.DAL.EF.Exceptions;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.ChangeTracking;
+using Microsoft.EntityFrameworkCore.Metadata;
+
+public abstract class BaseDbContext : DbContext
+{
+    private readonly IClock _clock;
+
+    protected BaseDbContext(DbContextOptions options, IClock clock)
+        : base(options)
+    {
+        _clock = clock;
+    }
+
+    public override int SaveChanges()
+    {
+        ApplyTimestamps();
+        return base.SaveChanges();
+    }
+
+    public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default)
+    {
+        ApplyTimestamps();
+        return await base.SaveChangesAsync(cancellationToken);
+    }
+
+    private void ApplyTimestamps()
+    {
+        DateTimeOffset now = _clock.UtcNow;
+
+        foreach (EntityEntry<IEntity> entry in ChangeTracker.Entries<IEntity>())
+        {
+            switch (entry.State)
+            {
+                case EntityState.Added:
+                    entry.Entity.Created = now;
+                    break;
+                case EntityState.Modified:
+                    entry.Entity.Updated = now;
+                    break;
+                case EntityState.Detached:
+                case EntityState.Unchanged:
+                case EntityState.Deleted:
+                    break;
+                default:
+                    throw new UnexpectedEntityStateException(entry.State);
+            }
+        }
+    }
+
+    protected override void ConfigureConventions(ModelConfigurationBuilder configurationBuilder)
+    {
+        configurationBuilder.Properties<DateTime>().HaveConversion<UtcValueConverter>();
+    }
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        foreach (IMutableForeignKey relationship in modelBuilder.Model.GetEntityTypes()
+                     .SelectMany(e => e.GetForeignKeys()))
+        {
+            relationship.DeleteBehavior = DeleteBehavior.Restrict;
+        }
+
+        modelBuilder.ApplyConfigurationsFromAssembly(GetType().Assembly);
+
+        base.OnModelCreating(modelBuilder);
+    }
+}

HrynCo.DAL.EF/Exceptions/UnexpectedEntityStateException.cs

@@ -0,0 +1,11 @@
+namespace HrynCo.DAL.EF.Exceptions;
+
+using Microsoft.EntityFrameworkCore;
+
+public sealed class UnexpectedEntityStateException : Exception
+{
+    public UnexpectedEntityStateException(EntityState state)
+        : base($"Unexpected entity state: {state}")
+    {
+    }
+}

HrynCo.DAL.EF/HrynCo.DAL.EF.csproj

@@ -18,6 +18,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="HrynCo.Common" />
     <PackageReference Include="Microsoft.EntityFrameworkCore" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Design">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>