(feature): thread safe file and json file logging, deep clone and compare of objects

README.md

@@ -13,6 +13,10 @@
   - [DataTable Extensions](#datatable-extensions)
   - [Guid Extensions](#guid-extensions)
 - [Logging](#logging)
+  - [File Logger](#file-logger)
+  - [JSON File Logger](#json-file-logger)
+- [Threading](#threading)
+  - [Lock Manager](#lock-manager)
 - [Networking](#networking)
   - [Network Connection](#network-connection)
   - [Ping Port](#ping-port)
@@ -511,33 +515,75 @@ string result = "example".Left(3); // "exa"
 
 #### Object Extensions
 
-The `ObjectExtensions` class provides methods for serializing objects to JSON strings and deserializing JSON strings back to objects.
+The `ObjectExtensions` class provides advanced methods for working with objects, including serialization, deep cloning, and structural equality comparison.
 
 ---
 
 #### Features
 
 1. **JSON Serialization**:
-   - Convert objects to JSON strings.
+   - Convert objects to JSON strings with optional custom converters.
 
-2. **JSON Deserialization**:
+2. **Deep Cloning**:
-   - Convert JSON strings back to objects.
+   - Create a deep clone of an object, preserving reference identity and supporting cycles.
+
+3. **Structural Equality**:
+   - Compare two objects deeply for structural equality, including private fields.
+
+4. **Snapshot Reversion**:
+   - Revert an object to a previous state by copying all fields from a snapshot.
 
 ---
 
 #### Example Usage
 
-##### Serialization
+##### JSON Serialization
 ```csharp
 var person = new { Name = "John", Age = 30 };
 string json = person.ToJson();
+
+// With custom converters
+var converters = new List<JsonConverter> { new CustomConverter() };
+string jsonWithConverters = person.ToJson(converters);
 ```
 
-##### Deserialization
+##### Deep Cloning
 ```csharp
-var person = json.ToObject<Person>();
+var original = new Person { Name = "John", Age = 30 };
+var clone = original.DeepClone();
 ```
 
+##### Structural Equality
+```csharp
+var person1 = new Person { Name = "John", Age = 30 };
+var person2 = new Person { Name = "John", Age = 30 };
+
+bool areEqual = person1.DeepEqual(person2); // True
+```
+
+##### Snapshot Reversion
+```csharp
+var snapshot = new Person { Name = "John", Age = 30 };
+var current = new Person { Name = "Doe", Age = 25 };
+
+current.RevertFrom(snapshot);
+// current.Name is now "John"
+// current.Age is now 30
+```
+
+---
+
+#### Best Practices
+
+1. **Use Deep Cloning for Complex Objects**:
+   - Ensure objects are deeply cloned when working with mutable reference types.
+
+2. **Validate Structural Equality**:
+   - Use `DeepEqual` for scenarios requiring precise object comparisons.
+
+3. **Revert State Safely**:
+   - Use `RevertFrom` to safely restore object states in tracked entities.
+
 ---
 
 #### DataTable Extensions
@@ -599,24 +645,26 @@ The `Logging` namespace provides a custom file-based logging implementation that
 
 ---
 
+### File Logger
+
+The `FileLogger` class in the `MaksIT.Core.Logging` namespace provides a simple and efficient way to log messages to plain text files. It supports log retention policies and ensures thread-safe writes using the `LockManager`.
+
 #### Features
 
-1. **File-Based Logging**:
+1. **Plain Text Logging**:
-   - Log messages to a specified file.
+   - Logs messages in a human-readable plain text format.
 
-2. **Log Levels**:
+2. **Log Retention**:
-   - Supports all standard log levels.
+   - Automatically deletes old log files based on a configurable retention period.
 
 3. **Thread Safety**:
-   - Ensures thread-safe writes to the log file.
+   - Ensures safe concurrent writes to the log file using the `LockManager`.
-
----
 
 #### Example Usage
 
 ```csharp
 var services = new ServiceCollection();
-services.AddLogging(builder => builder.AddFile("logs.txt"));
+services.AddLogging(builder => builder.AddFileLogger("logs", TimeSpan.FromDays(7)));
 
 var logger = services.BuildServiceProvider().GetRequiredService<ILogger<FileLogger>>();
 logger.LogInformation("Logging to file!");
@@ -624,6 +672,65 @@ logger.LogInformation("Logging to file!");
 
 ---
 
+### JSON File Logger
+
+The `JsonFileLogger` class in the `MaksIT.Core.Logging` namespace provides structured logging in JSON format. It is ideal for machine-readable logs and integrates seamlessly with log aggregation tools.
+
+#### Features
+
+1. **JSON Logging**:
+   - Logs messages in structured JSON format, including timestamps, log levels, and exceptions.
+
+2. **Log Retention**:
+   - Automatically deletes old log files based on a configurable retention period.
+
+3. **Thread Safety**:
+   - Ensures safe concurrent writes to the log file using the `LockManager`.
+
+#### Example Usage
+
+```csharp
+var services = new ServiceCollection();
+services.AddLogging(builder => builder.AddJsonFileLogger("logs", TimeSpan.FromDays(7)));
+
+var logger = services.BuildServiceProvider().GetRequiredService<ILogger<JsonFileLogger>>();
+logger.LogInformation("Logging to JSON file!");
+```
+
+---
+
+## Threading
+
+### Lock Manager
+
+The `LockManager` class in the `MaksIT.Core.Threading` namespace provides a robust solution for managing concurrency and rate limiting. It ensures safe access to shared resources in multi-threaded or multi-process environments.
+
+#### Features
+
+1. **Thread Safety**:
+   - Ensures mutual exclusion using a semaphore.
+
+2. **Rate Limiting**:
+   - Limits the frequency of access to shared resources using a token bucket rate limiter.
+
+3. **Reentrant Locks**:
+   - Supports reentrant locks for the same thread.
+
+#### Example Usage
+
+```csharp
+var lockManager = new LockManager();
+
+await lockManager.ExecuteWithLockAsync(async () => {
+    // Critical section
+    Console.WriteLine("Executing safely");
+});
+
+lockManager.Dispose();
+```
+
+---
+
 ## Networking
 
 ### Network Connection

src/MaksIT.Core.Tests/Extensions/ObjectExtensionsTests.cs

@@ -118,5 +118,199 @@ namespace MaksIT.Core.Tests.Extensions {
       // Assert
       Assert.Equal("{}", result);
     }
+
+    // ------- DeepClone / DeepEqual / RevertFrom tests below -------
+
+    private class Person {
+      public string Name = "";
+      public int Age;
+      private string _secret = "xyz";
+      public string Secret => _secret;
+      public void SetSecret(string s) { _secret = s; }
+      public Address? Addr;
+    }
+
+    private class Address {
+      public string City = "";
+      public Person? Owner; // cycle back to person
+    }
+
+    private struct Score {
+      public int A;
+      public List<Person>? People; // ref-type field inside struct
+    }
+
+    [Fact]
+    public void DeepClone_WithSimpleGraph_ShouldProduceIndependentCopy() {
+      // Arrange
+      var p = new Person { Name = "Alice", Age = 25, Addr = new Address { City = "Rome" } };
+
+      // Act
+      var clone = p.DeepClone();
+
+      // Assert
+      Assert.NotSame(p, clone);
+      Assert.Equal("Alice", clone.Name);
+      Assert.Equal(25, clone.Age);
+      Assert.NotSame(p.Addr, clone.Addr);
+      Assert.Equal("Rome", clone.Addr!.City);
+
+      // Mutate clone should not affect original
+      clone.Name = "Bob";
+      clone.Addr.City = "Milan";
+      clone.SetSecret("new");
+      Assert.Equal("Alice", p.Name);
+      Assert.Equal("Rome", p.Addr!.City);
+      Assert.Equal("xyz", p.Secret);
+    }
+
+    [Fact]
+    public void DeepClone_ShouldPreserveCyclesAndReferenceIdentity() {
+      // Arrange
+      var p = new Person { Name = "Root" };
+      var a = new Address { City = "Naples" };
+      p.Addr = a;
+      a.Owner = p; // create cycle
+
+      // Act
+      var clone = p.DeepClone();
+
+      // Assert
+      Assert.NotSame(p, clone);
+      Assert.NotSame(p.Addr, clone.Addr);
+      Assert.Same(clone, clone.Addr!.Owner); // cycle preserved in clone
+    }
+
+    [Fact]
+    public void DeepClone_ShouldHandleStructsWithReferenceFields() {
+      // Arrange
+      var s = new Score {
+        A = 7,
+        People = new List<Person> { new Person { Name = "P1" } }
+      };
+
+      // Act
+      var sClone = s.DeepClone();
+
+      // Assert
+      Assert.Equal(7, sClone.A);
+      Assert.NotSame(s.People, sClone.People);
+      Assert.NotSame(s.People![0], sClone.People![0]);
+      Assert.Equal("P1", sClone.People[0].Name);
+    }
+
+    [Fact]
+    public void DeepClone_ShouldHandleArraysAndMultiDimensional() {
+      // Arrange
+      var arr = new[] { new Person { Name = "A" }, new Person { Name = "B" } };
+      var md = (Person[,])Array.CreateInstance(typeof(Person), new[] { 1, 2 }, new[] { 1, 1 });
+      md[1, 1] = arr[0];
+      md[1, 2] = arr[1];
+
+      // Act
+      var arrClone = arr.DeepClone();
+      var mdClone = md.DeepClone();
+
+      // Assert
+      Assert.NotSame(arr, arrClone);
+      Assert.NotSame(arr[0], arrClone[0]);
+      Assert.Equal("A", arrClone[0].Name);
+
+      Assert.NotSame(md, mdClone);
+      Assert.Equal(md.GetLowerBound(0), mdClone.GetLowerBound(0));
+      Assert.Equal(md.GetLowerBound(1), mdClone.GetLowerBound(1));
+      Assert.NotSame(md[1, 1], mdClone[1, 1]);
+      Assert.Equal("A", mdClone[1, 1].Name);
+    }
+
+    [Fact]
+    public void DeepClone_ShouldReturnSameReferenceForImmutable() {
+      // Arrange
+      var s = "hello";
+
+      // Act
+      var s2 = s.DeepClone();
+
+      // Assert
+      Assert.Same(s, s2);
+    }
+
+    [Fact]
+    public void DeepEqual_ShouldReturnTrue_ForEqualGraphs() {
+      // Arrange
+      var p1 = new Person { Name = "Alice", Age = 30, Addr = new Address { City = "Turin" } };
+      var p2 = new Person { Name = "Alice", Age = 30, Addr = new Address { City = "Turin" } };
+
+      // Act
+      var equal = p1.DeepEqual(p2);
+
+      // Assert
+      Assert.True(equal);
+    }
+
+    [Fact]
+    public void DeepEqual_ShouldReturnFalse_WhenAnyFieldDiffers() {
+      // Arrange
+      var p1 = new Person { Name = "Alice", Age = 30, Addr = new Address { City = "Turin" } };
+      var p2 = new Person { Name = "Alice", Age = 31, Addr = new Address { City = "Turin" } };
+
+      // Act
+      var equal = p1.DeepEqual(p2);
+
+      // Assert
+      Assert.False(equal);
+    }
+
+    [Fact]
+    public void DeepEqual_ShouldHandleCycles() {
+      // Arrange
+      var p1 = new Person { Name = "R", Addr = new Address { City = "X" } };
+      p1.Addr!.Owner = p1;
+      var p2 = new Person { Name = "R", Addr = new Address { City = "X" } };
+      p2.Addr!.Owner = p2;
+
+      // Act
+      var equal = p1.DeepEqual(p2);
+
+      // Assert
+      Assert.True(equal);
+    }
+
+    [Fact]
+    public void RevertFrom_ShouldCopyStateBackOntoExistingInstance() {
+      // Arrange
+      var original = new Person { Name = "Alice", Age = 20, Addr = new Address { City = "Parma" } };
+      var snapshot = original.DeepClone();
+
+      // Mutate original
+      original.Name = "Changed";
+      original.Age = 99;
+      original.Addr!.City = "ChangedCity";
+      original.SetSecret("changed-secret");
+
+      // Act
+      original.RevertFrom(snapshot);
+
+      // Assert
+      Assert.Equal("Alice", original.Name);
+      Assert.Equal(20, original.Age);
+      Assert.Equal("Parma", original.Addr!.City);
+      Assert.Equal("xyz", original.Secret);
+    }
+
+    [Fact]
+    public void DeepEqual_NullsAndTypeMismatch_ShouldBehaveCorrectly() {
+      // Arrange
+      Person? a = null;
+      Person? b = null;
+      var c = new Person();
+      var d = new TestObject { Name = "x", Age = 1 };
+
+      // Act / Assert
+      Assert.True(a.DeepEqual(b));
+      Assert.False(a.DeepEqual(c));
+      // Different runtime types must be false
+      Assert.False(c.DeepEqual((object)d));
+    }
   }
 }

src/MaksIT.Core.Tests/LoggerHelper.cs

@@ -30,9 +30,8 @@ public static class LoggerHelper
 
         serviceCollection.AddLogging(builder =>
         {
-            var env = serviceCollection.BuildServiceProvider().GetRequiredService<IHostEnvironment>();
             builder.ClearProviders();
-            builder.AddConsole(env);
+            builder.AddConsoleLogger();
         });
 
         var provider = serviceCollection.BuildServiceProvider();

src/MaksIT.Core.Tests/Logging/FileLoggerTests.cs

@@ -28,7 +28,7 @@ public class FileLoggerTests {
             ContentRootPath = Directory.GetCurrentDirectory()
         });
 
-    serviceCollection.AddLogging(builder => builder.AddFile(_testFolderPath, TimeSpan.FromDays(7)));
+    serviceCollection.AddLogging(builder => builder.AddFileLogger(_testFolderPath, TimeSpan.FromDays(7)));
 
     var provider = serviceCollection.BuildServiceProvider();
     var logger = provider.GetRequiredService<ILogger<FileLoggerTests>>();
@@ -55,7 +55,7 @@ public class FileLoggerTests {
             ContentRootPath = Directory.GetCurrentDirectory()
         });
 
-    serviceCollection.AddLogging(builder => builder.AddFile(_testFolderPath, retentionPeriod));
+    serviceCollection.AddLogging(builder => builder.AddFileLogger(_testFolderPath, retentionPeriod));
 
     var provider = serviceCollection.BuildServiceProvider();
     var logger = provider.GetRequiredService<ILogger<FileLoggerTests>>();
@@ -86,7 +86,7 @@ public class FileLoggerTests {
             ContentRootPath = Directory.GetCurrentDirectory()
         });
 
-    serviceCollection.AddLogging(builder => builder.AddFile(_testFolderPath));
+    serviceCollection.AddLogging(builder => builder.AddFileLogger(_testFolderPath));
 
     var provider = serviceCollection.BuildServiceProvider();
     var logger = provider.GetRequiredService<ILogger<FileLoggerTests>>();

src/MaksIT.Core.Tests/Logging/JsonFileLoggerTests.cs

@@ -0,0 +1,143 @@
+using System.Text.Json;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using MaksIT.Core.Logging;
+
+
+namespace MaksIT.Core.Tests.Logging;
+
+public class JsonFileLoggerTests {
+  private readonly string _testFolderPath;
+
+  public JsonFileLoggerTests() {
+    _testFolderPath = Path.Combine(Path.GetTempPath(), "JsonFileLoggerTests");
+    if (Directory.Exists(_testFolderPath)) {
+      Directory.Delete(_testFolderPath, true);
+    }
+    Directory.CreateDirectory(_testFolderPath);
+  }
+
+  [Fact]
+  public void ShouldWriteLogsInJsonFormat() {
+    // Arrange
+    var serviceCollection = new ServiceCollection();
+    serviceCollection.AddSingleton<IHostEnvironment>(sp =>
+        new TestHostEnvironment {
+            EnvironmentName = Environments.Development,
+            ApplicationName = "TestApp",
+            ContentRootPath = Directory.GetCurrentDirectory()
+        });
+
+    serviceCollection.AddLogging(builder => builder.AddJsonFileLogger(_testFolderPath, TimeSpan.FromDays(7)));
+
+    var provider = serviceCollection.BuildServiceProvider();
+    var logger = provider.GetRequiredService<ILogger<JsonFileLoggerTests>>();
+
+    // Act
+    logger.LogInformation("Test JSON log message");
+
+    // Assert
+    var logFile = Directory.GetFiles(_testFolderPath, "log_*.json").FirstOrDefault();
+    Assert.NotNull(logFile);
+    var logContent = File.ReadAllText(logFile);
+    Assert.Contains("Test JSON log message", logContent);
+
+    var logEntry = JsonSerializer.Deserialize<JsonElement>(logContent.TrimEnd(','));
+    Assert.Equal("Information", logEntry.GetProperty("LogLevel").GetString());
+    Assert.Equal("Test JSON log message", logEntry.GetProperty("Message").GetString());
+  }
+
+  [Fact]
+  public void ShouldDeleteOldJsonLogsBasedOnRetention() {
+    // Arrange
+    var retentionPeriod = TimeSpan.FromDays(1);
+    var serviceCollection = new ServiceCollection();
+    serviceCollection.AddSingleton<IHostEnvironment>(sp =>
+        new TestHostEnvironment {
+            EnvironmentName = Environments.Development,
+            ApplicationName = "TestApp",
+            ContentRootPath = Directory.GetCurrentDirectory()
+        });
+
+    serviceCollection.AddLogging(builder => builder.AddJsonFileLogger(_testFolderPath, retentionPeriod));
+
+    var provider = serviceCollection.BuildServiceProvider();
+    var logger = provider.GetRequiredService<ILogger<JsonFileLoggerTests>>();
+
+    // Create an old log file
+    var oldLogFile = Path.Combine(_testFolderPath, $"log_{DateTime.Now.AddDays(-2):yyyy-MM-dd}.json");
+    File.WriteAllText(oldLogFile, "{\"Message\":\"Old log\"}");
+
+    // Act
+    logger.LogInformation("New JSON log message");
+
+    // Assert
+    Assert.False(File.Exists(oldLogFile), "Old JSON log file should have been deleted.");
+    var logFile = Directory.GetFiles(_testFolderPath, "log_*.json").FirstOrDefault();
+    Assert.NotNull(logFile);
+    var logContent = File.ReadAllText(logFile);
+    Assert.Contains("New JSON log message", logContent);
+  }
+
+  [Fact]
+  public void ShouldLogExceptionsInJsonFormat() {
+    // Arrange
+    var serviceCollection = new ServiceCollection();
+    serviceCollection.AddSingleton<IHostEnvironment>(sp =>
+        new TestHostEnvironment {
+            EnvironmentName = Environments.Development,
+            ApplicationName = "TestApp",
+            ContentRootPath = Directory.GetCurrentDirectory()
+        });
+
+    serviceCollection.AddLogging(builder => builder.AddJsonFileLogger(_testFolderPath, TimeSpan.FromDays(7)));
+
+    var provider = serviceCollection.BuildServiceProvider();
+    var logger = provider.GetRequiredService<ILogger<JsonFileLoggerTests>>();
+
+    // Act
+    logger.LogError(new InvalidOperationException("Test exception"), "An error occurred");
+
+    // Assert
+    var logFile = Directory.GetFiles(_testFolderPath, "log_*.json").FirstOrDefault();
+    Assert.NotNull(logFile);
+    var logContent = File.ReadAllText(logFile);
+    Assert.Contains("An error occurred", logContent);
+    Assert.Contains("Test exception", logContent);
+
+    var logEntry = JsonSerializer.Deserialize<JsonElement>(logContent.TrimEnd(','));
+    Assert.Equal("Error", logEntry.GetProperty("LogLevel").GetString());
+    Assert.Equal("An error occurred", logEntry.GetProperty("Message").GetString());
+    Assert.Contains("Test exception", logEntry.GetProperty("Exception").GetString());
+  }
+
+  [Fact]
+  public void ShouldWorkWithConsoleLogger() {
+    // Arrange
+    var serviceCollection = new ServiceCollection();
+    serviceCollection.AddSingleton<IHostEnvironment>(sp =>
+        new TestHostEnvironment {
+            EnvironmentName = Environments.Development,
+            ApplicationName = "TestApp",
+            ContentRootPath = Directory.GetCurrentDirectory()
+        });
+
+    serviceCollection.AddLogging(builder => {
+      builder.AddJsonFileLogger(_testFolderPath, TimeSpan.FromDays(7));
+      builder.AddSimpleConsoleLogger();
+    });
+
+    var provider = serviceCollection.BuildServiceProvider();
+    var logger = provider.GetRequiredService<ILogger<JsonFileLoggerTests>>();
+
+    // Act
+    logger.LogInformation("Test combined logging");
+
+    // Assert
+    var logFile = Directory.GetFiles(_testFolderPath, "log_*.json").FirstOrDefault();
+    Assert.NotNull(logFile);
+    var logContent = File.ReadAllText(logFile);
+    Assert.Contains("Test combined logging", logContent);
+  }
+}

src/MaksIT.Core.Tests/Threading/LockManagerTests.cs

@@ -0,0 +1,105 @@
+using System.Diagnostics;
+using MaksIT.Core.Threading;
+
+namespace MaksIT.Core.Tests.Threading;
+
+public class LockManagerTests {
+  [Fact]
+  public async Task ShouldEnsureThreadSafety() {
+    // Arrange
+    var lockManager = new LockManager();
+    int counter = 0;
+
+    // Act
+    var tasks = Enumerable.Range(0, 10).Select(_ => lockManager.ExecuteWithLockAsync(async () => {
+      int temp = counter;
+      await Task.Delay(10); // Simulate work
+      counter = temp + 1;
+    }));
+
+    await Task.WhenAll(tasks);
+
+    // Assert
+    Assert.Equal(10, counter);
+  }
+
+  [Fact]
+  public async Task ShouldEnforceRateLimiting() {
+    // Arrange
+    var lockManager = new LockManager();
+    var stopwatch = Stopwatch.StartNew();
+
+    // Act
+    var tasks = Enumerable.Range(0, 10).Select(_ => lockManager.ExecuteWithLockAsync(async () => {
+      await Task.Delay(10); // Simulate work
+    }));
+
+    await Task.WhenAll(tasks);
+    stopwatch.Stop();
+
+    // With 1 token and 200ms replenishment:
+    // first task starts immediately, remaining 9 wait ~9 * 200ms = ~1800ms + overhead.
+    // Allow some jitter on CI.
+    Assert.InRange(stopwatch.ElapsedMilliseconds, 1700, 6000);
+  }
+
+  [Fact]
+  public async Task ShouldAllowReentrantLocks() {
+    // Arrange
+    var lockManager = new LockManager();
+    int counter = 0;
+
+    // Act
+    await lockManager.ExecuteWithLockAsync(async () => {
+      await lockManager.ExecuteWithLockAsync(() => {
+        counter++;
+        return Task.CompletedTask;
+      });
+    });
+
+    // Assert
+    Assert.Equal(1, counter);
+  }
+
+  [Fact]
+  public async Task ShouldHandleExceptionsGracefully() {
+    // Arrange
+    var lockManager = new LockManager();
+    int counter = 0;
+
+    // Act & Assert
+    await Assert.ThrowsAsync<InvalidOperationException>(async () => {
+      await lockManager.ExecuteWithLockAsync(async () => {
+        counter++;
+        throw new InvalidOperationException("Test exception");
+      });
+    });
+
+    // Ensure lock is not in an inconsistent state
+    await lockManager.ExecuteWithLockAsync(() => {
+      counter++;
+      return Task.CompletedTask;
+    });
+
+    Assert.Equal(2, counter);
+  }
+
+  [Fact]
+  public async Task ShouldSupportConcurrentAccess() {
+    // Arrange
+    var lockManager = new LockManager();
+    int counter = 0;
+
+    // Act
+    var tasks = Enumerable.Range(0, 100).Select(_ => lockManager.ExecuteWithLockAsync(async () => {
+      int temp = counter;
+      await Task.Delay(1); // Simulate work
+      counter = temp + 1;
+    }));
+
+    await Task.WhenAll(tasks);
+
+    // Assert
+    Assert.Equal(100, counter);
+  }
+}

src/MaksIT.Core/Extensions/ObjectExtensions.cs

@@ -1,7 +1,11 @@
-using System.Text.Json;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.Serialization;
+using System.Text.Json;
 using System.Text.Json.Serialization;
 
-namespace MaksIT.Core.Extensions; 
+
+namespace MaksIT.Core.Extensions;
 
 public static class ObjectExtensions {
 
@@ -33,4 +37,232 @@ public static class ObjectExtensions {
 
     return JsonSerializer.Serialize(obj, options);
   }
+
+  /// <summary>
+  /// Creates a deep clone of the object, preserving reference identity and supporting cycles.
+  /// </summary>
+  public static T DeepClone<T>(this T source) {
+    return (T)DeepCloneInternal(source, new Dictionary<object, object>(ReferenceEqualityComparer.Instance));
+  }
+
+  /// <summary>
+  /// Deeply compares two objects for structural equality (fields, including private ones).
+  /// </summary>
+  public static bool DeepEqual<T>(this T a, T b) {
+    return DeepEqualInternal(a, b, new HashSet<(object, object)>(ReferencePairComparer.Instance));
+  }
+
+  /// <summary>
+  /// Copies all fields from the snapshot into the current target object (useful with tracked entities).
+  /// </summary>
+  public static void RevertFrom<T>(this T target, T snapshot) {
+    if (ReferenceEquals(target, snapshot) || target == null || snapshot == null) return;
+    var visited = new Dictionary<object, object>(ReferenceEqualityComparer.Instance);
+    CopyAllFields(snapshot!, target!, snapshot!.GetType(), visited);
+  }
+
+  #region Internal Cloner
+
+  private static object DeepCloneInternal(object source, Dictionary<object, object> visited) {
+    if (source == null) return null!;
+
+    var type = source.GetType();
+
+    // Fast-path for immutable/primitive-ish types
+    if (IsImmutable(type)) return source;
+
+    // Already cloned?
+    if (!type.IsValueType && visited.TryGetValue(source, out var existing))
+      return existing;
+
+    // Arrays
+    if (type.IsArray)
+      return CloneArray((Array)source, visited);
+
+    // Value types (structs): shallow copy via boxing + clone ref-type fields
+    if (type.IsValueType)
+      return CloneStruct(source, type, visited);
+
+    // Reference type: allocate uninitialized object, then copy fields
+    var clone = FormatterServices.GetUninitializedObject(type);
+    visited[source] = clone;
+    CopyAllFields(source, clone, type, visited);
+    return clone;
+  }
+
+  private static bool IsImmutable(Type t) {
+    if (t.IsPrimitive || t.IsEnum) return true;
+
+    // Common immutable BCL types
+    if (t == typeof(string) ||
+        t == typeof(decimal) ||
+        t == typeof(DateTime) ||
+        t == typeof(DateTimeOffset) ||
+        t == typeof(TimeSpan) ||
+        t == typeof(Guid) ||
+        t == typeof(Uri))
+      return true;
+
+    // Nullable<T> of immutable underlying
+    if (Nullable.GetUnderlyingType(t) is Type nt)
+      return IsImmutable(nt);
+
+    return false;
+  }
+
+  private static Array CloneArray(Array source, Dictionary<object, object> visited) {
+    var elemType = source.GetType().GetElementType()!;
+    var rank = source.Rank;
+
+    var lengths = new int[rank];
+    var lowers = new int[rank];
+    for (int d = 0; d < rank; d++) {
+      lengths[d] = source.GetLength(d);
+      lowers[d] = source.GetLowerBound(d);
+    }
+
+    var clone = Array.CreateInstance(elemType, lengths, lowers);
+    visited[source] = clone;
+
+    var indices = new int[rank];
+    CopyArrayRecursive(source, clone, 0, indices, lowers, lengths, visited);
+    return clone;
+  }
+
+  private static void CopyArrayRecursive(
+    Array source,
+    Array target,
+    int dim,
+    int[] indices,
+    int[] lowers,
+    int[] lengths,
+    Dictionary<object, object> visited) {
+    if (dim == source.Rank) {
+      var value = source.GetValue(indices);
+      var cloned = DeepCloneInternal(value!, visited);
+      target.SetValue(cloned, indices);
+      return;
+    }
+
+    int start = lowers[dim];
+    int end = lowers[dim] + lengths[dim];
+    for (int i = start; i < end; i++) {
+      indices[dim] = i;
+      CopyArrayRecursive(source, target, dim + 1, indices, lowers, lengths, visited);
+    }
+  }
+
+  private static object CloneStruct(object source, Type type, Dictionary<object, object> visited) {
+    // Boxed copy is already a shallow copy of the struct
+    object boxed = source;
+    CopyAllFields(boxed, boxed, type, visited, skipVisitedRegistration: true);
+    return boxed;
+  }
+
+  private static void CopyAllFields(object source, object target, Type type, Dictionary<object, object> visited, bool skipVisitedRegistration = false) {
+    for (Type t = type; t != null; t = t.BaseType!) {
+      var fields = t.GetFields(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.DeclaredOnly);
+      foreach (var f in fields) {
+        var value = f.GetValue(source);
+        var cloned = DeepCloneInternal(value!, visited);
+        f.SetValue(target, cloned);
+      }
+    }
+  }
+
+  #endregion
+
+  #region Internal Deep-Equal
+
+  private static bool DeepEqualInternal(object a, object b, HashSet<(object, object)> visited) {
+    if (ReferenceEquals(a, b))
+      return true;
+    if (a == null || b == null)
+      return false;
+
+    var type = a.GetType();
+    if (type != b.GetType())
+      return false;
+
+    // Fast path for immutables
+    if (IsImmutable(type))
+      return a.Equals(b);
+
+    // Prevent infinite recursion on cycles
+    var pair = (a, b);
+    if (visited.Contains(pair))
+      return true;
+    visited.Add(pair);
+
+    // Arrays
+    if (type.IsArray)
+      return ArraysEqual((Array)a, (Array)b, visited);
+
+    // Value or reference types: compare fields recursively
+    return FieldsEqual(a, b, type, visited);
+  }
+
+  private static bool ArraysEqual(Array a, Array b, HashSet<(object, object)> visited) {
+    if (a.Rank != b.Rank) return false;
+    for (int d = 0; d < a.Rank; d++) {
+      if (a.GetLength(d) != b.GetLength(d) || a.GetLowerBound(d) != b.GetLowerBound(d))
+        return false;
+    }
+
+    var indices = new int[a.Rank];
+    return CompareArrayRecursive(a, b, 0, indices, visited);
+  }
+
+  private static bool CompareArrayRecursive(Array a, Array b, int dim, int[] indices, HashSet<(object, object)> visited) {
+    if (dim == a.Rank) {
+      var va = a.GetValue(indices);
+      var vb = b.GetValue(indices);
+      return DeepEqualInternal(va!, vb!, visited);
+    }
+
+    int start = a.GetLowerBound(dim);
+    int end = start + a.GetLength(dim);
+    for (int i = start; i < end; i++) {
+      indices[dim] = i;
+      if (!CompareArrayRecursive(a, b, dim + 1, indices, visited))
+        return false;
+    }
+    return true;
+  }
+
+  private static bool FieldsEqual(object a, object b, Type type, HashSet<(object, object)> visited) {
+    for (Type t = type; t != null; t = t.BaseType!) {
+      var fields = t.GetFields(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.DeclaredOnly);
+      foreach (var f in fields) {
+        var va = f.GetValue(a);
+        var vb = f.GetValue(b);
+        if (!DeepEqualInternal(va!, vb!, visited))
+          return false;
+      }
+    }
+    return true;
+  }
+
+  #endregion
+
+  #region Helpers
+
+  private sealed class ReferenceEqualityComparer : IEqualityComparer<object> {
+    public static readonly ReferenceEqualityComparer Instance = new ReferenceEqualityComparer();
+    public new bool Equals(object x, object y) => ReferenceEquals(x, y);
+    public int GetHashCode(object obj) => RuntimeHelpers.GetHashCode(obj);
+  }
+
+  private sealed class ReferencePairComparer : IEqualityComparer<(object, object)> {
+    public static readonly ReferencePairComparer Instance = new ReferencePairComparer();
+    public bool Equals((object, object) x, (object, object) y)
+      => ReferenceEquals(x.Item1, y.Item1) && ReferenceEquals(x.Item2, y.Item2);
+    public int GetHashCode((object, object) obj) {
+      unchecked {
+        return (RuntimeHelpers.GetHashCode(obj.Item1) * 397) ^ RuntimeHelpers.GetHashCode(obj.Item2);
+      }
+    }
+  }
+
+  #endregion
 }

src/MaksIT.Core/Logging/BaseFileLogger.cs

@@ -0,0 +1,57 @@
+using System;
+using System.IO;
+using MaksIT.Core.Threading;
+using Microsoft.Extensions.Logging;
+
+namespace MaksIT.Core.Logging;
+
+public abstract class BaseFileLogger : ILogger, IDisposable {
+  private readonly LockManager _lockManager = new LockManager();
+  private readonly string _folderPath;
+  private readonly TimeSpan _retentionPeriod;
+
+  protected BaseFileLogger(string folderPath, TimeSpan retentionPeriod) {
+    _folderPath = folderPath;
+    _retentionPeriod = retentionPeriod;
+    Directory.CreateDirectory(_folderPath); // Ensure the folder exists
+  }
+
+  public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
+
+  public bool IsEnabled(LogLevel logLevel) {
+    return logLevel != LogLevel.None;
+  }
+
+  public abstract void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter);
+
+  protected string GenerateLogFileName(string extension) {
+    return Path.Combine(_folderPath, $"log_{DateTime.UtcNow:yyyy-MM-dd}.{extension}");
+  }
+
+  protected void AppendToLogFile(string logFileName, string content) {
+    _lockManager.ExecuteWithLockAsync(async () => {
+      await File.AppendAllTextAsync(logFileName, content);
+      RemoveExpiredLogFiles(Path.GetExtension(logFileName));
+    }).Wait();
+  }
+
+  private void RemoveExpiredLogFiles(string extension) {
+    var filePattern = $"log_*.{extension.TrimStart('.')}";
+
+    var logFiles = Directory.GetFiles(_folderPath, filePattern);
+    var expirationDate = DateTime.UtcNow - _retentionPeriod;
+
+    foreach (var logFile in logFiles) {
+      var fileName = Path.GetFileNameWithoutExtension(logFile);
+      if (DateTime.TryParseExact(fileName.Substring(4), "yyyy-MM-dd", null, System.Globalization.DateTimeStyles.None, out var logDate)) {
+        if (logDate < expirationDate) {
+          File.Delete(logFile);
+        }
+      }
+    }
+  }
+
+  public void Dispose() {
+    _lockManager.Dispose();
+  }
+}

src/MaksIT.Core/Logging/FileLogger.cs

@@ -1,26 +1,11 @@
 using Microsoft.Extensions.Logging;
-using System.IO;
 
 namespace MaksIT.Core.Logging;
 
-public class FileLogger : ILogger {
+public class FileLogger : BaseFileLogger {
-  private readonly string _folderPath;
+  public FileLogger(string folderPath, TimeSpan retentionPeriod) : base(folderPath, retentionPeriod) { }
-  private readonly object _lock = new object();
-  private readonly TimeSpan _retentionPeriod;
 
-  public FileLogger(string folderPath, TimeSpan retentionPeriod) {
+  public override void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter) {
-    _folderPath = folderPath;
-    _retentionPeriod = retentionPeriod;
-    Directory.CreateDirectory(_folderPath); // Ensure the folder exists
-  }
-
-  public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
-
-  public bool IsEnabled(LogLevel logLevel) {
-    return logLevel != LogLevel.None;
-  }
-
-  public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter) {
     if (!IsEnabled(logLevel))
       return;
 
@@ -28,30 +13,12 @@ public class FileLogger : ILogger {
     if (string.IsNullOrEmpty(message))
       return;
 
-    var logRecord = $"{DateTime.Now:yyyy-MM-dd HH:mm:ss} [{logLevel}] {message}";
+    var logRecord = $"{DateTime.UtcNow.ToString("o")} [{logLevel}] {message}";
     if (exception != null) {
       logRecord += Environment.NewLine + exception;
     }
 
-    var logFileName = Path.Combine(_folderPath, $"log_{DateTime.Now:yyyy-MM-dd}.txt"); // Generate log file name by date
+    var logFileName = GenerateLogFileName("txt");
-
+    AppendToLogFile(logFileName, logRecord + Environment.NewLine);
-    lock (_lock) {
-      File.AppendAllText(logFileName, logRecord + Environment.NewLine);
-      CleanUpOldLogs();
-    }
-  }
-
-  private void CleanUpOldLogs() {
-    var logFiles = Directory.GetFiles(_folderPath, "log_*.txt");
-    var expirationDate = DateTime.Now - _retentionPeriod;
-
-    foreach (var logFile in logFiles) {
-      var fileName = Path.GetFileNameWithoutExtension(logFile);
-      if (DateTime.TryParseExact(fileName.Substring(4), "yyyy-MM-dd", null, System.Globalization.DateTimeStyles.None, out var logDate)) {
-        if (logDate < expirationDate) {
-          File.Delete(logFile);
-        }
-      }
-    }
   }
 }

src/MaksIT.Core/Logging/JsonFileLogger.cs

@@ -0,0 +1,23 @@
+using Microsoft.Extensions.Logging;
+using System.Text.Json;
+
+namespace MaksIT.Core.Logging;
+
+public class JsonFileLogger : BaseFileLogger {
+  public JsonFileLogger(string folderPath, TimeSpan retentionPeriod) : base(folderPath, retentionPeriod) { }
+
+  public override void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter) {
+    if (!IsEnabled(logLevel))
+      return;
+
+    var logEntry = new {
+      Timestamp = DateTime.UtcNow.ToString("o"),
+      LogLevel = logLevel.ToString(),
+      Message = formatter(state, exception),
+      Exception = exception?.ToString()
+    };
+
+    var logFileName = GenerateLogFileName("json");
+    AppendToLogFile(logFileName, JsonSerializer.Serialize(logEntry) + Environment.NewLine);
+  }
+}

src/MaksIT.Core/Logging/JsonFileLoggerProvider.cs

@@ -0,0 +1,20 @@
+using Microsoft.Extensions.Logging;
+
+namespace MaksIT.Core.Logging;
+
+[ProviderAlias("JsonFileLogger")]
+public class JsonFileLoggerProvider : ILoggerProvider {
+  private readonly string _folderPath;
+  private readonly TimeSpan _retentionPeriod;
+
+  public JsonFileLoggerProvider(string folderPath, TimeSpan? retentionPeriod = null) {
+    _folderPath = folderPath ?? throw new ArgumentNullException(nameof(folderPath));
+    _retentionPeriod = retentionPeriod ?? TimeSpan.FromDays(7); // Default retention period is 7 days
+  }
+
+  public ILogger CreateLogger(string categoryName) {
+    return new JsonFileLogger(_folderPath, _retentionPeriod);
+  }
+
+  public void Dispose() { }
+}

src/MaksIT.Core/Logging/LoggingBuilderExtensions.cs

@@ -5,25 +5,48 @@ using Microsoft.Extensions.Hosting;
 namespace MaksIT.Core.Logging;
 
 public static class LoggingBuilderExtensions {
-  public static ILoggingBuilder AddFile(this ILoggingBuilder builder, string folderPath, TimeSpan? retentionPeriod = null) {
+  public static ILoggingBuilder AddFileLogger(this ILoggingBuilder logging, string folderPath, TimeSpan? retentionPeriod = null) {
-    builder.Services.AddSingleton<ILoggerProvider>(new FileLoggerProvider(folderPath, retentionPeriod));
+    logging.Services.AddSingleton<ILoggerProvider>(new FileLoggerProvider(folderPath, retentionPeriod));
-    return builder;
+    return logging;
   }
-  public static ILoggingBuilder AddConsole(this ILoggingBuilder logging, IHostEnvironment env) {
+
+  public static ILoggingBuilder AddJsonFileLogger(this ILoggingBuilder logging, string folderPath, TimeSpan? retentionPeriod = null) {
+    logging.Services.AddSingleton<ILoggerProvider>(new JsonFileLoggerProvider(folderPath, retentionPeriod));
+    return logging;
+  }
+
+  public static ILoggingBuilder AddSimpleConsoleLogger(this ILoggingBuilder logging) {
+    logging.AddSimpleConsole(options => {
+      options.IncludeScopes = true;
+      options.SingleLine = false;
+      options.TimestampFormat = "yyyy-MM-ddTHH:mm:ss.fffZ";
+    });
+    return logging;
+  }
+
+  public static ILoggingBuilder AddJsonConsoleLogger(this ILoggingBuilder logging) {
+    logging.AddJsonConsole(options => {
+      options.IncludeScopes = true;
+      options.TimestampFormat = "yyyy-MM-ddTHH:mm:ss.fffZ";
+    });
+    return logging;
+  }
+
+  public static ILoggingBuilder AddConsoleLogger(this ILoggingBuilder logging, string? fileLoggerPath = null) {
     logging.ClearProviders();
-    if (env.IsDevelopment()) {
+    logging.AddSimpleConsoleLogger();
-      logging.AddSimpleConsole(options => {
+
-        options.IncludeScopes = true;
+    if (fileLoggerPath != null)
-        options.SingleLine = false;
+      logging.AddFileLogger(fileLoggerPath);
-        options.TimestampFormat = "hh:mm:ss ";
+
-      });
+    return logging;
-    }
+  }
-    else {
+
-      logging.AddJsonConsole(options => {
+  public static ILoggingBuilder AddJsonConsoleLogger(this ILoggingBuilder logging, string? fileLoggerPath = null) {
-        options.IncludeScopes = true;
+    logging.ClearProviders();
-        options.TimestampFormat = "yyyy-MM-ddTHH:mm:ss.fffZ";
+    logging.AddJsonConsoleLogger();
-      });
+    if (fileLoggerPath != null)
-    }
+      logging.AddJsonFileLogger(fileLoggerPath);
     return logging;
   }
 }

src/MaksIT.Core/MaksIT.Core.csproj

@@ -8,7 +8,7 @@
 
     <!-- NuGet package metadata -->
     <PackageId>MaksIT.Core</PackageId>
-    <Version>1.5.0</Version>
+    <Version>1.5.1</Version>
     <Authors>Maksym Sadovnychyy</Authors>
     <Company>MAKS-IT</Company>
     <Product>MaksIT.Core</Product>
@@ -35,5 +35,6 @@
     <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="8.14.0" />
     <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="8.14.0" />
     <PackageReference Include="System.Linq.Dynamic.Core" Version="1.6.9" />
+    <PackageReference Include="System.Threading.RateLimiting" Version="9.0.10" />
   </ItemGroup>
 </Project>

src/MaksIT.Core/Threading/LockManager.cs

@@ -0,0 +1,74 @@
+using System.Collections.Concurrent;
+using System.Threading.RateLimiting;
+
+namespace MaksIT.Core.Threading;
+
+public class LockManager : IDisposable {
+  private readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1);
+
+  // Use AsyncLocal to track reentrancy in the same async flow
+  private static readonly AsyncLocal<int> _reentrancyDepth = new AsyncLocal<int>();
+
+  // Strict limiter: allow 1 token, replenish 1 every 200ms
+  private readonly TokenBucketRateLimiter _rateLimiter = new TokenBucketRateLimiter(new TokenBucketRateLimiterOptions {
+    TokenLimit = 1, // Single concurrent entry
+    QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
+    QueueLimit = 1_000,
+    ReplenishmentPeriod = TimeSpan.FromMilliseconds(200), // 1 token every 200ms
+    TokensPerPeriod = 1,
+    AutoReplenishment = true
+  });
+
+  public async Task<T> ExecuteWithLockAsync<T>(Func<Task<T>> action) {
+    var lease = await _rateLimiter.AcquireAsync(1);
+    if (!lease.IsAcquired) throw new InvalidOperationException("Rate limit exceeded");
+
+    // Determine if this is the first entry for the current async flow
+    bool isFirstEntry = false;
+    if (_reentrancyDepth.Value == 0) {
+      isFirstEntry = true;
+      _reentrancyDepth.Value = 1;
+    }
+    else {
+      _reentrancyDepth.Value = _reentrancyDepth.Value + 1;
+    }
+
+    if (isFirstEntry) await _semaphore.WaitAsync();
+    try {
+      return await action();
+    }
+    finally {
+      // Decrement reentrancy; release semaphore only when depth reaches zero
+      var newDepth = _reentrancyDepth.Value - 1;
+      _reentrancyDepth.Value = newDepth < 0 ? 0 : newDepth;
+
+      if (isFirstEntry) _semaphore.Release();
+
+      // Dispose the lease to complete the rate-limited window
+      lease.Dispose();
+    }
+  }
+
+  public async Task ExecuteWithLockAsync(Func<Task> action) {
+    await ExecuteWithLockAsync(async () => {
+      await action();
+      return true;
+    });
+  }
+
+  public async Task<T> ExecuteWithLockAsync<T>(Func<T> action) {
+    return await ExecuteWithLockAsync(() => Task.FromResult(action()));
+  }
+
+  public async Task ExecuteWithLockAsync(Action action) {
+    await ExecuteWithLockAsync(() => {
+      action();
+      return Task.CompletedTask;
+    });
+  }
+
+  public void Dispose() {
+    _semaphore.Dispose();
+    _rateLimiter.Dispose();
+  }
+}