refactor: Vereinfachung der SQLExecutor-Implementierung zur Rückgabe von IQueryExecutor

- Aktualisiert `SQLExecutor<T>` um `ISQLExecutor<T>` zu implementieren und `IQueryExecutor<T>` für die weitere Abfrageausführung zurückzugeben.
- Umstrukturierte Methoden zur Verwendung von `ToExecutor()` für die Konvertierung von rohen SQL-Abfragen in einen `IQueryExecutor<T>`.
- Geänderter Konstruktor, um `IServiceProvider` für die Injektion von Abhängigkeiten von benutzerdefinierten SQL-Abfrageklassen zu akzeptieren.

EnvelopeGenerator.Application/Contracts/SQLExecutor/IQueryExecutor.cs

@@ -0,0 +1,70 @@
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// Provides methods for executing common Entity Framework queries on a given entity type.
+/// This interface abstracts away the direct usage of Entity Framework methods for querying data
+/// and provides asynchronous and synchronous operations for querying a collection or single entity.
+/// </summary>
+/// <typeparam name="TEntity">The type of the entity being queried.</typeparam>
+public interface IQueryExecutor<TEntity>
+{
+    /// <summary>
+    /// Asynchronously retrieves the first entity or a default value if no entity is found.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation. The task result contains the entity or a default value.</returns>
+    public Task<TEntity?> FirstOrDefaultAsync();
+
+    /// <summary>
+    /// Asynchronously retrieves a single entity or a default value if no entity is found.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation. The task result contains the entity or a default value.</returns>
+    public Task<TEntity?> SingleOrDefaultAsync();
+
+    /// <summary>
+    /// Asynchronously retrieves a list of entities.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation. The task result contains the list of entities.</returns>
+    public Task<IEnumerable<TEntity>> ToListAsync();
+
+    /// <summary>
+    /// Asynchronously retrieves the first entity. Throws an exception if no entity is found.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation. The task result contains the first entity.</returns>
+    public Task<TEntity> FirstAsync();
+
+    /// <summary>
+    /// Asynchronously retrieves a single entity. Throws an exception if no entity is found.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation. The task result contains the single entity.</returns>
+    public Task<TEntity> SingleAsync();
+
+    /// <summary>
+    /// Synchronously retrieves the first entity or a default value if no entity is found.
+    /// </summary>
+    /// <returns>The first entity or a default value.</returns>
+    public TEntity? FirstOrDefault();
+
+    /// <summary>
+    /// Synchronously retrieves a single entity or a default value if no entity is found.
+    /// </summary>
+    /// <returns>The single entity or a default value.</returns>
+    public TEntity? SingleOrDefault();
+
+    /// <summary>
+    /// Synchronously retrieves a list of entities.
+    /// </summary>
+    /// <returns>The list of entities.</returns>
+    public IEnumerable<TEntity> ToList();
+
+    /// <summary>
+    /// Synchronously retrieves the first entity. Throws an exception if no entity is found.
+    /// </summary>
+    /// <returns>The first entity.</returns>
+    public TEntity First();
+
+    /// <summary>
+    /// Synchronously retrieves a single entity. Throws an exception if no entity is found.
+    /// </summary>
+    /// <returns>The single entity.</returns>
+    public TEntity Single();
+}

EnvelopeGenerator.Application/Contracts/SQLExecutor/ISQL.cs

@@ -0,0 +1,20 @@
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// Represents a raw SQL query contract.
+/// </summary>
+public interface ISQL
+{
+    /// <summary>
+    /// Gets the raw SQL query string.
+    /// </summary>
+    string Raw { get; }
+}
+
+/// <summary>
+/// Represents a typed SQL query contract for a specific entity.
+/// </summary>
+/// <typeparam name="TEntity">The type of the entity associated with the SQL query.</typeparam>
+public interface ISQL<TEntity> : ISQL
+{
+}

EnvelopeGenerator.Application/Contracts/SQLExecutor/ISQLExecutor.cs

@@ -0,0 +1,27 @@
+namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+
+/// <summary>
+/// Defines methods for executing raw SQL queries or custom SQL query classes and returning query executors for further operations.
+/// Provides abstraction for raw SQL execution as well as mapping the results to <typeparamref name="TEntity"/> objects.
+/// </summary>
+/// <typeparam name="TEntity">The entity type to which the SQL query results will be mapped.</typeparam>
+public interface ISQLExecutor<TEntity>
+{
+    /// <summary>
+    /// Executes a raw SQL query and returns an <see cref="IQueryExecutor{TEntity}"/> for further querying operations on the result.
+    /// </summary>
+    /// <param name="sql">The raw SQL query to execute.</param>
+    /// <param name="cancellation">Optional cancellation token for the operation.</param>
+    /// <param name="parameters">Optional parameters for the SQL query.</param>
+    /// <returns>An <see cref="IQueryExecutor{TEntity}"/> instance for further query operations on the result.</returns>
+    IQueryExecutor<TEntity> Execute(string sql, CancellationToken cancellation = default, params object[] parameters);
+
+    /// <summary>
+    /// Executes a custom SQL query defined by a class that implements <see cref="ISQL{TEntity}"/> and returns an <see cref="IQueryExecutor{TEntity}"/> for further querying operations on the result.
+    /// </summary>
+    /// <typeparam name="TSQL">The type of the custom SQL query class implementing <see cref="ISQL{TEntity}"/>.</typeparam>
+    /// <param name="cancellation">Optional cancellation token for the operation.</param>
+    /// <param name="parameters">Optional parameters for the SQL query.</param>
+    /// <returns>An <see cref="IQueryExecutor{TEntity}"/> instance for further query operations on the result.</returns>
+    IQueryExecutor<TEntity> Execute<TSQL>(CancellationToken cancellation = default, params object[] parameters) where TSQL : ISQL<TEntity>;
+}

EnvelopeGenerator.Application/EnvelopeGenerator.Application.csproj

@@ -80,4 +80,8 @@
 	  </PackageReference>
 	</ItemGroup>
 
+	<ItemGroup>
+	  <Folder Include="Procedures\" />
+	</ItemGroup>
+
 </Project>

EnvelopeGenerator.Application/EnvelopeReceivers/Commands/Create/CreateEnvelopeReceiverCommandHandler.cs

@@ -0,0 +1,24 @@
+using MediatR;
+
+namespace EnvelopeGenerator.Application.EnvelopeReceivers.Commands.Create;
+
+/// <summary>
+/// Handles the creation of an envelope along with its associated document and recipients.
+/// This command processes the envelope data, including title, message, document content,
+/// recipient list, and optional two-factor authentication settings.
+/// </summary>
+public class CreateEnvelopeReceiverCommandHandler : IRequestHandler<CreateEnvelopeReceiverCommand>
+{
+    /// <summary>
+    /// Handles the execution of the <see cref="CreateEnvelopeReceiverCommand"/>.
+    /// Responsible for validating input data, creating or retrieving recipients, associating signatures,
+    /// and storing the envelope and document details.
+    /// </summary>
+    /// <param name="request">The command containing all necessary information to create an envelope.</param>
+    /// <param name="cancellationToken">Token to observe while waiting for the task to complete.</param>
+    /// <returns>A task representing the asynchronous operation.</returns>
+    public Task Handle(CreateEnvelopeReceiverCommand request, CancellationToken cancellationToken)
+    {
+        throw new NotImplementedException();
+    }
+}

EnvelopeGenerator.GeneratorAPI/Models/Login.cs

@@ -6,8 +6,8 @@ namespace EnvelopeGenerator.GeneratorAPI.Models;
 /// Repräsentiert ein Login-Modell mit erforderlichem Passwort und optionaler ID und Benutzername.
 /// </summary>
 /// <param name="Password">Das erforderliche Passwort für das Login.</param>
-/// <param name="Id">Die optionale ID des Benutzers.</param>
+/// <param name="UserId">Die optionale ID des Benutzers.</param>
 /// <param name="Username">Der optionale Benutzername.</param>
-public record Login([Required] string Password, int? Id = null, string? Username = null)
+public record Login([Required] string Password, int? UserId = null, string? Username = null)
 {
 }

EnvelopeGenerator.GeneratorAPI/Properties/launchSettings.json

@@ -22,7 +22,7 @@
     "https": {
       "commandName": "Project",
       "dotnetRunMessages": true,
-      "launchBrowser": true,
+      "launchBrowser": false,
       "launchUrl": "swagger",
       "applicationUrl": "https://localhost:7174;http://localhost:5131",
       "environmentVariables": {

EnvelopeGenerator.Infrastructure/QueryExecutor.cs

@@ -0,0 +1,42 @@
+using AngleSharp.Dom;
+using EnvelopeGenerator.Application.Contracts.SQLExecutor;
+using Microsoft.EntityFrameworkCore;
+
+namespace EnvelopeGenerator.Infrastructure;
+
+public sealed record QueryExecutor<TEntity> : IQueryExecutor<TEntity>
+{
+    private readonly IQueryable<TEntity> _query;
+
+    internal QueryExecutor(IQueryable<TEntity> queryable)
+    {
+        _query = queryable;
+    }
+
+    public TEntity First() => _query.First();
+
+    public Task<TEntity> FirstAsync() => _query.FirstAsync();
+
+    public TEntity? FirstOrDefault() => _query.FirstOrDefault();
+
+
+    public Task<TEntity?> FirstOrDefaultAsync() => _query.FirstOrDefaultAsync();
+
+
+    public TEntity Single() => _query.Single();
+
+
+    public Task<TEntity> SingleAsync() => _query.SingleAsync();
+
+
+    public TEntity? SingleOrDefault() => _query.SingleOrDefault();
+
+
+    public Task<TEntity?> SingleOrDefaultAsync() => _query.SingleOrDefaultAsync();
+
+
+    public IEnumerable<TEntity> ToList() => _query.ToList();
+
+
+    public async Task<IEnumerable<TEntity>> ToListAsync() => await _query.ToListAsync();
+}

EnvelopeGenerator.Infrastructure/QueryExecutorExtension.cs

@@ -0,0 +1,9 @@
+namespace EnvelopeGenerator.Infrastructure;
+
+public static class QueryExecutorExtension
+{
+    public static QueryExecutor<TEntity> ToExecutor<TEntity>(this IQueryable<TEntity> queryable) where TEntity : class
+    {
+        return new QueryExecutor<TEntity>(queryable);
+    }
+}

EnvelopeGenerator.Infrastructure/SQLExecutor.cs

@@ -0,0 +1,30 @@
+using EnvelopeGenerator.Application.Contracts.SQLExecutor;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace EnvelopeGenerator.Infrastructure;
+
+public sealed class SQLExecutor<T> : ISQLExecutor<T> where T : class
+{
+    private readonly EGDbContext _context;
+
+    private readonly IServiceProvider _provider;
+
+    public SQLExecutor(EGDbContext context, IServiceProvider provider)
+    {
+        _context = context;
+        _provider = provider;
+    }
+
+    public IQueryExecutor<T> Execute(string sql, CancellationToken cancellation = default, params object[] parameters)
+        => _context
+            .Set<T>()
+            .FromSqlRaw(sql, parameters)
+            .ToExecutor();
+
+    public IQueryExecutor<T> Execute<TSQL>(CancellationToken cancellation = default, params object[] parameters) where TSQL : ISQL<T>
+    {
+        var sql = _provider.GetRequiredService<TSQL>();
+        return Execute(sql.Raw);
+    }
+}