Refactor repository pattern and mark methods obsolete

Updated `IRepository<TEntity>` to introduce new reading methods and mark existing ones as obsolete. The `CRUDRepository` class is now deprecated, encouraging a transition to alternative implementations. Significant changes in `DbRepository<TDbContext, TEntity>` include the removal of old read methods in favor of a new `Read` method returning `IReadQuery<TEntity>`. Added a `ReadQuery<TEntity>` class to enhance querying capabilities with a fluent API. Obsolete methods are organized under a `#region Obsolete` directive for better management.

DigitalData.Core.Application/Interfaces/Repository/IRepository.cs

@@ -16,6 +16,7 @@ public interface IRepository<TEntity>
 
     public Task DeleteAsync(Expression<Func<TEntity, bool>> expression, CancellationToken cancellation = default);
 
+    #region Obsolete
     [Obsolete("Use Read-method returning IReadQuery<TEntity> instead.")]
     public Task<IEnumerable<TEntity>> ReadAllAsync(Expression<Func<TEntity, bool>>? expression = null, CancellationToken cancellation = default);
 
@@ -27,4 +28,5 @@ public interface IRepository<TEntity>
 
     [Obsolete("Use Read-method returning IReadQuery<TEntity> instead.")]
     public Task<TDto?> ReadOrDefaultAsync<TDto>(Expression<Func<TEntity, bool>> expression, bool single = true, CancellationToken cancellation = default);
+    #endregion
 }

DigitalData.Core.Infrastructure/CRUDRepository.cs

@@ -15,6 +15,7 @@ namespace DigitalData.Core.Infrastructure
     /// This repository abstracts the common database operations, offering an asynchronous API to work with the entity's data.
     /// It leverages the EF Core's DbContext and DbSet to perform these operations.
     /// </remarks>
+    [Obsolete("Use Repository")]
     public class CRUDRepository<TEntity, TId, TDbContext> : ICRUDRepository<TEntity, TId>
         where TEntity : class
         where TDbContext : DbContext

DigitalData.Core.Infrastructure/DbRepository.cs

@@ -33,24 +33,7 @@ public class DbRepository<TDbContext, TEntity> : IRepository<TEntity> where TDbC
         return entities;
     }
 
-    public virtual async Task<IEnumerable<TEntity>> ReadAllAsync(Expression<Func<TEntity, bool>>? expression = null, CancellationToken ct = default)
+    public IReadQuery<TEntity> Read(params Expression<Func<TEntity, bool>>[] expressions) => new ReadQuery<TEntity>(Entities.AsNoTracking()).Where(expressions);
-        => expression is null
-            ? await Entities.AsNoTracking().ToListAsync(ct)
-            : await Entities.AsNoTracking().Where(expression).ToListAsync(ct);
-
-    public virtual async Task<TEntity?> ReadOrDefaultAsync(Expression<Func<TEntity, bool>> expression, bool single = true, CancellationToken ct = default)
-        => single 
-            ? await Entities.AsNoTracking().Where(expression).SingleOrDefaultAsync(ct)
-            : await Entities.AsNoTracking().Where(expression).FirstOrDefaultAsync(ct);
-
-    public virtual async Task<IEnumerable<TDto>> ReadAllAsync<TDto>(Expression<Func<TEntity, bool>>? expression = null, CancellationToken ct = default)
-        => Mapper.Map<TDto>(await ReadAllAsync(expression, ct));
-
-    public virtual async Task<TDto?> ReadOrDefaultAsync<TDto>(Expression<Func<TEntity, bool>> expression, bool single = true, CancellationToken ct = default)
-    {
-        var entity = await ReadOrDefaultAsync(expression, single, ct);
-        return entity is null ? default : Mapper.Map<TDto>(entity);
-    }
     
     public virtual async Task UpdateAsync<TDto>(TDto dto, Expression<Func<TEntity, bool>> expression, CancellationToken ct = default)
     {
@@ -76,4 +59,29 @@ public class DbRepository<TDbContext, TEntity> : IRepository<TEntity> where TDbC
 
         await Context.SaveChangesAsync(ct);
     }
+
+    #region Obsolete
+    [Obsolete("Use Read-method returning IReadQuery<TEntity> instead.")]
+    public virtual async Task<IEnumerable<TEntity>> ReadAllAsync(Expression<Func<TEntity, bool>>? expression = null, CancellationToken ct = default)
+        => expression is null
+            ? await Entities.AsNoTracking().ToListAsync(ct)
+            : await Entities.AsNoTracking().Where(expression).ToListAsync(ct);
+
+    [Obsolete("Use Read-method returning IReadQuery<TEntity> instead.")]
+    public virtual async Task<TEntity?> ReadOrDefaultAsync(Expression<Func<TEntity, bool>> expression, bool single = true, CancellationToken ct = default)
+        => single
+            ? await Entities.AsNoTracking().Where(expression).SingleOrDefaultAsync(ct)
+            : await Entities.AsNoTracking().Where(expression).FirstOrDefaultAsync(ct);
+
+    [Obsolete("Use Read-method returning IReadQuery<TEntity> instead.")]
+    public virtual async Task<IEnumerable<TDto>> ReadAllAsync<TDto>(Expression<Func<TEntity, bool>>? expression = null, CancellationToken ct = default)
+        => Mapper.Map<TDto>(await ReadAllAsync(expression, ct));
+
+    [Obsolete("Use Read-method returning IReadQuery<TEntity> instead.")]
+    public virtual async Task<TDto?> ReadOrDefaultAsync<TDto>(Expression<Func<TEntity, bool>> expression, bool single = true, CancellationToken ct = default)
+    {
+        var entity = await ReadOrDefaultAsync(expression, single, ct);
+        return entity is null ? default : Mapper.Map<TDto>(entity);
+    }
+    #endregion
 }

DigitalData.Core.Infrastructure/ReadQuery.cs

@@ -0,0 +1,48 @@
+using DigitalData.Core.Application.Interfaces.Repository;
+using Microsoft.EntityFrameworkCore;
+using System.Linq.Expressions;
+
+namespace DigitalData.Core.Infrastructure;
+
+public sealed record ReadQuery<TEntity> : IReadQuery<TEntity>
+{
+    private IQueryable<TEntity> _query;
+
+    internal ReadQuery(IQueryable<TEntity> queryable)
+    {
+        _query = queryable;
+    }
+
+    public TEntity First() => _query.First();
+
+    public Task<TEntity> FirstAsync(CancellationToken cancellation = default) => _query.FirstAsync(cancellation);
+
+    public TEntity? FirstOrDefault() => _query.FirstOrDefault();
+
+
+    public Task<TEntity?> FirstOrDefaultAsync(CancellationToken cancellation = default) => _query.FirstOrDefaultAsync(cancellation);
+
+
+    public TEntity Single() => _query.Single();
+
+
+    public Task<TEntity> SingleAsync(CancellationToken cancellation = default) => _query.SingleAsync(cancellation);
+
+
+    public TEntity? SingleOrDefault() => _query.SingleOrDefault();
+
+
+    public Task<TEntity?> SingleOrDefaultAsync(CancellationToken cancellation = default) => _query.SingleOrDefaultAsync(cancellation);
+
+
+    public IEnumerable<TEntity> ToList() => _query.ToList();
+
+
+    public async Task<IEnumerable<TEntity>> ToListAsync(CancellationToken cancellation = default) => await _query.ToListAsync(cancellation);
+
+    public IReadQuery<TEntity> Where(Expression<Func<TEntity, bool>> expression)
+    {
+        _query = _query.Where(expression);
+        return this;
+    }
+}