feat: introduce LogLevel value object and improve logger API

- Replace LogLevel enum with a dedicated class that encapsulates
  log level representation.
- Add factory methods for creating Debug, Info, and Error levels.
- Add string conversion support through LogLevel::toString().
- Add equality comparison operators for LogLevel instances.

- Rename Logger::writeLog() to writeMessage().
- Add writeMessage() overload that uses the default log level.
- Implement actual file writing with error handling using core::Status.
- Improve logger documentation to reflect the updated API.

- Update logger tests to use the new LogLevel API.
- Move logger tests into the core test directory.
- Replace enum-based log level usage with LogLevel factory methods.
- Update test cases for the renamed writeMessage() method.

Makefile

@@ -17,8 +17,8 @@ RESULT_TEST_BIN := $(BUILD_DIR)/result_test
 LOGGER_TEST_BIN := $(BUILD_DIR)/logger_test
 SCOPED_FILE_TEST_BIN := $(BUILD_DIR)/scoped_file_test
 
-RESULT_TEST_SRC := tests/app/core/result_test.cpp
+RESULT_TEST_SRC := tests/core/result_test.cpp
-LOGGER_TEST_SRC := tests/app/core/logger_test.cpp
+LOGGER_TEST_SRC := tests/core/logger_test.cpp
 SCOPED_FILE_TEST_SRC := tests/helpers/scoped_file_test.cpp
 
 LOGGER_SRC := logger/src/logger.cpp

logger/include/log_level.hpp

@@ -1,7 +1,75 @@
 #pragma once
 
+#include <string_view>
+
 namespace logger {
 
-enum class LogLevel { Debug = 0, Info = 1, Error = 2 };
+/**
+ * @brief Представляет уровень логирования.
+ *
+ * Экземпляры класса создаются только через статические фабричные методы.
+ */
+class LogLevel {
+public:
+  /**
+   * @brief Создает уровень Debug.
+   */
+  static LogLevel debug() { return LogLevel(Type::Debug); }
+
+  /**
+   * @brief Создает уровень Info.
+   */
+  static LogLevel info() { return LogLevel(Type::Info); }
+
+  /**
+   * @brief Создает уровень Error.
+   */
+  static LogLevel error() { return LogLevel(Type::Error); }
+
+  /**
+   * @brief Возвращает строковое представление уровня.
+   *
+   * @return "DEBUG", "INFO" или "ERROR".
+   */
+  [[nodiscard]]
+  std::string_view toString() const {
+    switch (type_) {
+    case Type::Debug:
+      return "DEBUG";
+
+    case Type::Info:
+      return "INFO";
+
+    case Type::Error:
+      return "ERROR";
+    }
+
+    return "UNKNOWN";
+  }
+
+  /**
+   * @brief Сравнивает два уровня логирования.
+   */
+  [[nodiscard]]
+  bool operator==(const LogLevel &other) const {
+    return type_ == other.type_;
+  }
+
+  /**
+   * @brief Сравнивает два уровня логирования.
+   */
+  [[nodiscard]]
+  bool operator!=(const LogLevel &other) const {
+    return !(*this == other);
+  }
+
+private:
+  enum class Type { Debug, Info, Error };
+
+  explicit LogLevel(Type type) : type_(type) {}
+
+private:
+  Type type_;
+};
 
 } // namespace logger

logger/include/logger.hpp

@@ -58,18 +58,33 @@ public:
   Logger &operator=(Logger &&) = delete;
 
   /**
-   * @brief Записывает сообщение в журнал.
+   * @brief Записывает сообщение в журнал с указанным уровнем логирования.
    *
    * В случае успешной записи возвращается успешный Status.
    * При ошибке открытия файла или записи возвращается Status
    * с описанием ошибки.
    *
-   * @param level Уровень важности сообщения.
+   * @param level Уровень логирования сообщения.
    * @param message Текст сообщения.
    *
    * @return Статус выполнения операции.
    */
-  core::Status writeLog(LogLevel level, const std::string &message);
+  core::Status writeMessage(LogLevel level, const std::string &message);
+
+  /**
+   * @brief Записывает сообщение в журнал с уровнем логирования по умолчанию.
+   *
+   * Метод является удобной перегрузкой и эквивалентен вызову:
+   *
+   * @code
+   * writeMessage(getLogLevel(), message);
+   * @endcode
+   *
+   * @param message Текст сообщения.
+   *
+   * @return Статус выполнения операции.
+   */
+  core::Status writeMessage(const std::string &message);
 
   /**
    * @brief Создаёт новый Logger с изменённым уровнем логирования.
@@ -96,14 +111,14 @@ public:
   /**
    * @brief Возвращает текущий уровень логирования.
    *
-   * @return Уровень логирования.
+   * @return Уровень логирования по умолчанию.
    */
   LogLevel getLogLevel() const;
 
   /**
    * @brief Возвращает имя файла журнала.
    *
-   * @return Имя файла.
+   * @return Имя файла журнала.
    */
   const std::string &getFileName() const;
 

logger/src/logger.cpp

@@ -1,7 +1,7 @@
-// logger.cpp
-
 #include "logger.hpp"
 
+#include <fstream>
+
 namespace logger {
 
 Logger::Logger(const std::string &fileName, LogLevel defaultLevel)
@@ -9,11 +9,26 @@ Logger::Logger(const std::string &fileName, LogLevel defaultLevel)
 
 Logger::~Logger() = default;
 
-core::Status Logger::writeLog(LogLevel /*level*/,
+core::Status Logger::writeMessage(LogLevel level, const std::string &message) {
-                              const std::string & /*message*/) {
+  std::ofstream stream(fileName_, std::ios::app);
+
+  if (!stream.is_open()) {
+    return core::Status::Failure("Unable to open log file: " + fileName_);
+  }
+
+  stream << "[" << level.toString() << "] " << message << '\n';
+
+  if (!stream.good()) {
+    return core::Status::Failure("Failed to write to log file: " + fileName_);
+  }
+
   return core::Status::Success(true);
 }
 
+core::Status Logger::writeMessage(const std::string &message) {
+  return writeMessage(defaultLevel_, message);
+}
+
 Logger Logger::withLogLevel(LogLevel level) const {
   return Logger(fileName_, level);
 }

tests/core/logger_test.cpp

@@ -6,30 +6,32 @@
 
 namespace {
 
+using namespace logger;
+
 void testLoggerCreation() {
-  logger::Logger logger("test.log", logger::LogLevel::Info);
+  Logger logger("test.log", LogLevel::info());
 
   assert(logger.getFileName() == "test.log");
-  assert(logger.getLogLevel() == logger::LogLevel::Info);
+  assert(logger.getLogLevel() == LogLevel::info());
 }
 
 void testWithLogLevel() {
-  logger::Logger logger("test.log", logger::LogLevel::Info);
+  Logger logger("test.log", LogLevel::info());
 
-  auto debugLogger = logger.withLogLevel(logger::LogLevel::Debug);
+  auto debugLogger = logger.withLogLevel(LogLevel::debug());
 
   // Исходный объект не изменился
-  assert(logger.getLogLevel() == logger::LogLevel::Info);
+  assert(logger.getLogLevel() == LogLevel::info());
 
   // Новый объект получил новый уровень
-  assert(debugLogger.getLogLevel() == logger::LogLevel::Debug);
+  assert(debugLogger.getLogLevel() == LogLevel::debug());
 
   // Имя файла сохранилось
   assert(debugLogger.getFileName() == "test.log");
 }
 
 void testWithFileName() {
-  logger::Logger logger("old.log", logger::LogLevel::Info);
+  Logger logger("old.log", LogLevel::info());
 
   auto newLogger = logger.withFileName("new.log");
 
@@ -40,15 +42,15 @@ void testWithFileName() {
   assert(newLogger.getFileName() == "new.log");
 
   // Уровень сохранился
-  assert(newLogger.getLogLevel() == logger::LogLevel::Info);
+  assert(newLogger.getLogLevel() == LogLevel::info());
 }
 
 void testWriteLogSuccess() {
   const std::string fileName = "logger_test.log";
 
-  logger::Logger logger(fileName, logger::LogLevel::Info);
+  Logger logger(fileName, LogLevel::info());
 
-  auto result = logger.writeLog(logger::LogLevel::Info, "Application started");
+  auto result = logger.writeMessage(LogLevel::info(), "Application started");
 
   assert(result.isSuccess());
   assert(result.getValue());
@@ -68,9 +70,9 @@ void testWriteLogSuccess() {
 }
 
 void testWriteLogFailure() {
-  logger::Logger logger("/invalid/path/logger.log", logger::LogLevel::Info);
+  Logger logger("/invalid/path/logger.log", LogLevel::info());
 
-  auto result = logger.writeLog(logger::LogLevel::Info, "message");
+  auto result = logger.writeMessage(LogLevel::info(), "message");
 
   assert(result.isFailure());
   assert(!result.getError().empty());
@@ -79,11 +81,11 @@ void testWriteLogFailure() {
 void testMultipleWrites() {
   const std::string fileName = "multiple.log";
 
-  logger::Logger logger(fileName, logger::LogLevel::Info);
+  Logger logger(fileName, LogLevel::info());
 
-  assert(logger.writeLog(logger::LogLevel::Info, "first").isSuccess());
+  assert(logger.writeMessage(LogLevel::info(), "first").isSuccess());
 
-  assert(logger.writeLog(logger::LogLevel::Error, "second").isSuccess());
+  assert(logger.writeMessage(LogLevel::error(), "second").isSuccess());
 
   std::ifstream file(fileName);
 

tests/core/result_test.cpp

@@ -6,36 +6,38 @@
 
 namespace {
 
+using namespace core;
+
 void testSuccessCreation() {
-  auto result = core::Result<int>::Success(42);
+  auto result = Result<int>::Success(42);
 
   assert(result.isSuccess());
   assert(result.getValue() == 42);
 }
 
 void testFailureCreation() {
-  auto result = core::Result<int>::Failure("Invalid value");
+  auto result = Result<int>::Failure("Invalid value");
 
   assert(result.isFailure());
   assert(result.getError() == "Invalid value");
 }
 
 void testStatusSuccess() {
-  auto status = core::Status::Success(true);
+  auto status = Status::Success(true);
 
   assert(status.isSuccess());
   assert(status.getValue());
 }
 
 void testStatusFailure() {
-  auto status = core::Status::Failure("File not found");
+  auto status = Status::Failure("File not found");
 
   assert(status.isFailure());
   assert(status.getError() == "File not found");
 }
 
 void testMoveConstruction() {
-  auto source = core::Result<std::string>::Success("hello");
+  auto source = Result<std::string>::Success("hello");
 
   auto moved = std::move(source);
 
@@ -44,8 +46,8 @@ void testMoveConstruction() {
 }
 
 void testMoveAssignment() {
-  auto first = core::Result<int>::Success(10);
+  auto first = Result<int>::Success(10);
-  auto second = core::Result<int>::Failure("error");
+  auto second = Result<int>::Failure("error");
 
   second = std::move(first);
 
@@ -59,7 +61,7 @@ void testDifferentTypes() {
     std::string name;
   };
 
-  auto result = core::Result<User>::Success(User{1, "Alex"});
+  auto result = Result<User>::Success(User{1, "Alex"});
 
   assert(result.isSuccess());
   assert(result.getValue().id == 1);
@@ -67,7 +69,7 @@ void testDifferentTypes() {
 }
 
 void testValueModification() {
-  auto result = core::Result<int>::Success(10);
+  auto result = Result<int>::Success(10);
 
   result.getValue() = 20;
 
@@ -75,7 +77,7 @@ void testValueModification() {
 }
 
 void testErrorModification() {
-  auto result = core::Result<int>::Failure("old error");
+  auto result = Result<int>::Failure("old error");
 
   result.getError() = "new error";
 
@@ -85,7 +87,7 @@ void testErrorModification() {
 void testBasicResultWithCustomError() {
   enum class ErrorCode { NotFound, PermissionDenied };
 
-  using CustomResult = core::BasicResult<int, ErrorCode>;
+  using CustomResult = BasicResult<int, ErrorCode>;
 
   auto result = CustomResult::Failure(ErrorCode::PermissionDenied);
 

tests/helpers/scoped_file.hpp

@@ -4,6 +4,8 @@
 #include <stdexcept>
 #include <string>
 
+namespace helpers {
+
 class ScopedFile {
 public:
   explicit ScopedFile(std::string fileName) : fileName_(std::move(fileName)) {}
@@ -25,3 +27,5 @@ public:
 private:
   std::string fileName_;
 };
+
+} // namespace helpers

tests/helpers/scoped_file_test.cpp

@@ -8,6 +8,8 @@
 
 namespace {
 
+using namespace helpers;
+
 void testFileRemovedAfterScope() {
   const std::string fileName = "scoped_file_test.log";
 

tests/logger/logger_test.cpp

@@ -8,33 +8,35 @@
 
 namespace {
 
+using namespace logger;
+
 void testLoggerCreation() {
-  logger::Logger logger("test.log", logger::LogLevel::Info);
+  Logger logger("test.log", LogLevel::info());
 
   assert(logger.getFileName() == "test.log");
-  assert(logger.getLogLevel() == logger::LogLevel::Info);
+  assert(logger.getLogLevel() == LogLevel::info());
 }
 
 void testWithLogLevel() {
-  logger::Logger logger("test.log", logger::LogLevel::Info);
+  Logger logger("test.log", LogLevel::info());
 
-  auto debugLogger = logger.withLogLevel(logger::LogLevel::Debug);
+  auto debugLogger = logger.withLogLevel(LogLevel::debug());
 
-  assert(logger.getLogLevel() == logger::LogLevel::Info);
+  assert(logger.getLogLevel() == LogLevel::info());
-  assert(debugLogger.getLogLevel() == logger::LogLevel::Debug);
+  assert(debugLogger.getLogLevel() == LogLevel::debug());
 
   assert(debugLogger.getFileName() == "test.log");
 }
 
 void testWithFileName() {
-  logger::Logger logger("old.log", logger::LogLevel::Info);
+  Logger logger("old.log", LogLevel::info());
 
   auto newLogger = logger.withFileName("new.log");
 
   assert(logger.getFileName() == "old.log");
   assert(newLogger.getFileName() == "new.log");
 
-  assert(newLogger.getLogLevel() == logger::LogLevel::Info);
+  assert(newLogger.getLogLevel() == LogLevel::info());
 }
 
 void testWriteLogSuccess() {
@@ -42,9 +44,9 @@ void testWriteLogSuccess() {
 
   file.throwIfExists();
 
-  logger::Logger logger(file.getFileName(), logger::LogLevel::Info);
+  Logger logger(file.getFileName(), LogLevel::info());
 
-  auto result = logger.writeLog(logger::LogLevel::Info, "Application started");
+  auto result = logger.writeMessage(LogLevel::info(), "Application started");
 
   assert(result.isSuccess());
   assert(result.getValue());
@@ -66,9 +68,9 @@ void testWriteLogFailure() {
 
   std::filesystem::create_directory(file.getFileName());
 
-  logger::Logger logger(file.getFileName(), logger::LogLevel::Info);
+  Logger logger(file.getFileName(), LogLevel::info());
 
-  auto result = logger.writeLog(logger::LogLevel::Info, "message");
+  auto result = logger.writeMessage(LogLevel::info(), "message");
 
   assert(result.isFailure());
   assert(!result.getError().empty());
@@ -81,11 +83,11 @@ void testMultipleWrites() {
 
   file.throwIfExists();
 
-  logger::Logger logger(file.getFileName(), logger::LogLevel::Info);
+  Logger logger(file.getFileName(), LogLevel::info());
 
-  auto first = logger.writeLog(logger::LogLevel::Info, "first message");
+  auto first = logger.writeMessage(LogLevel::info(), "first message");
 
-  auto second = logger.writeLog(logger::LogLevel::Error, "second message");
+  auto second = logger.writeMessage(LogLevel::error(), "second message");
 
   assert(first.isSuccess());
   assert(second.isSuccess());