diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..e291365
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,9 @@
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 4
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
diff --git a/.gitignore b/.gitignore
index 485dee6..dfffa9f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,4 @@
 .idea
+application.log
+/vendor/
+composer.lock
diff --git a/Logger.php b/Logger.php
index 3caccbb..d05eec1 100644
--- a/Logger.php
+++ b/Logger.php
@@ -1,23 +1,39 @@
 <?php
 
+declare(strict_types=1);
+
+require 'vendor/autoload.php';
+
+use Homework\Logger\AbstractHandler;
+use Homework\Logger\HandlerFactory;
+use Homework\Logger\Type;
 
 class Logger
 {
-    public static function get()
-    {
-        return new Logger();
-    }
+    private static $instance = null;
 
-    public function logError($message)
+    public static function get(): AbstractHandler
     {
-        $logFile = fopen('application.log', 'w');
-        fwrite($logFile, 'ERROR: ' . $message);
-        fclose($logFile);
+        if (self::$instance == null) {
+            self::$instance = HandlerFactory::get(self::getHandlerType());
+        }
+
+        return self::$instance;
     }
 
-    public function logSuccess($msg)
+    /**
+     * Get handler type.
+     *
+     * @return Type
+     */
+    private static function getHandlerType(): Type
     {
-        $logFile = fopen('application.log', 'a');
-        fwrite($logFile, 'SUCCESS: ' . $msg);
+        if (count($_SERVER['argv']) > 1) {
+            if ($_SERVER['argv'][1] === '-c' || $_SERVER['argv'][1] === '--console') {
+                return Type::CONSOLE;
+            }
+        }
+
+        return Type::FILE;
     }
-}
\ No newline at end of file
+}
diff --git a/Logger/AbstractHandler.php b/Logger/AbstractHandler.php
new file mode 100644
index 0000000..4bd721b
--- /dev/null
+++ b/Logger/AbstractHandler.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Homework\Logger;
+
+/**
+ * Abstract class for handlers.
+ */
+abstract class AbstractHandler
+{
+    /**
+     * Add error entity to log.
+     *
+     * @param string $message
+     *
+     * @return boolean
+     */
+    public function logError(string $message): bool
+    {
+        return $this->log(Status::ERROR, $message);
+    }
+
+    /**
+     * Add success entity to log.
+     *
+     * @param string $message
+     *
+     * @return boolean
+     */
+    public function logSuccess(string $message): bool
+    {
+        return $this->log(Status::SUCCESS, $message);
+    }
+}
diff --git a/Logger/ConsoleHandler.php b/Logger/ConsoleHandler.php
new file mode 100644
index 0000000..1434b37
--- /dev/null
+++ b/Logger/ConsoleHandler.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Homework\Logger;
+
+/**
+ * Console logger handler.
+ */
+class ConsoleHandler extends AbstractHandler implements HandlerInterface
+{
+    use ValidationTrait;
+
+    /**
+     * Add log entity to console.
+     *
+     * @param Status $type
+     * @param string $message
+     *
+     * @return boolean
+     */
+    public function log(Status $type, string $message): bool
+    {
+        if (!$this->validate($message)) {
+            return false;
+        }
+
+        $file = fopen('php://stdout', 'a');
+
+        fwrite($file, sprintf("%s: %s\n", $type->getLabel(), $message));
+
+        return fclose($file);
+    }
+}
diff --git a/Logger/FileHandler.php b/Logger/FileHandler.php
new file mode 100644
index 0000000..7304c7e
--- /dev/null
+++ b/Logger/FileHandler.php
@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Homework\Logger;
+
+use Exception;
+
+/**
+ * File logger handler.
+ */
+class FileHandler extends AbstractHandler implements HandlerInterface
+{
+    use ValidationTrait;
+
+    public function __construct(private string $LOG_FILE = __DIR__ . '/../application.log')
+    {
+    }
+
+    /**
+     * Add log entity to file.
+     *
+     * @param Status $type
+     * @param string $message
+     *
+     * @return boolean
+     */
+    public function log(Status $type, string $message): bool
+    {
+        if (!$this->createFile()) {
+            return false;
+        }
+
+        if (!$this->validate($message)) {
+            return false;
+        }
+
+        $file = fopen($this->LOG_FILE, 'a');
+
+        fwrite($file, sprintf("%s: %s\n", $type->getLabel(), $message));
+
+        return fclose($file);
+    }
+
+    /**
+     * Check if file exists or not.
+     *
+     * @return boolean
+     */
+    private function fileExists(): bool
+    {
+        return file_exists($this->LOG_FILE) && is_file($this->LOG_FILE) && is_writable($this->LOG_FILE);
+    }
+
+    /**
+     * Create file if not exists.
+     *
+     * @return boolean
+     */
+    private function createFile(): bool
+    {
+        if (!$this->fileExists() && !fopen($this->LOG_FILE, 'c')) {
+            throw new Exception('Cannot create file');
+        }
+
+        return $this->fileExists();
+    }
+}
diff --git a/Logger/HandlerFactory.php b/Logger/HandlerFactory.php
new file mode 100644
index 0000000..7c13097
--- /dev/null
+++ b/Logger/HandlerFactory.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Homework\Logger;
+
+/**
+ * Handler factory.
+ */
+class HandlerFactory
+{
+    /**
+     * Get handler instance.
+     *
+     * @param Type $type
+     *
+     * @return AbstractHandler
+     */
+    public static function get(Type $type = Type::FILE): AbstractHandler
+    {
+        return match ($type) {
+            Type::FILE => new FileHandler(),
+            Type::CONSOLE => new ConsoleHandler()
+        };
+    }
+}
diff --git a/Logger/HandlerInterface.php b/Logger/HandlerInterface.php
new file mode 100644
index 0000000..645704a
--- /dev/null
+++ b/Logger/HandlerInterface.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Homework\Logger;
+
+/**
+ * Interface for handlers.
+ */
+interface HandlerInterface
+{
+    /**
+     * Add entity to log.
+     *
+     * @param Status $type
+     * @param string $message
+     *
+     * @return boolean
+     */
+    public function log(Status $type, string $message): bool;
+}
diff --git a/Logger/Status.php b/Logger/Status.php
new file mode 100644
index 0000000..22fe057
--- /dev/null
+++ b/Logger/Status.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Homework\Logger;
+
+/**
+ * Log entity status.
+ */
+enum Status
+{
+    case ERROR;
+    case SUCCESS;
+
+    /**
+     * Get text label for status.
+     *
+     * @return string
+     */
+    public function getLabel(): string
+    {
+        return match ($this) {
+            Status::ERROR => 'Error',
+            Status::SUCCESS => 'Success'
+        };
+    }
+}
diff --git a/Logger/Type.php b/Logger/Type.php
new file mode 100644
index 0000000..0e33372
--- /dev/null
+++ b/Logger/Type.php
@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Homework\Logger;
+
+/**
+ * Handler types.
+ */
+enum Type
+{
+    case FILE;
+    case CONSOLE;
+}
diff --git a/Logger/ValidationTrait.php b/Logger/ValidationTrait.php
new file mode 100644
index 0000000..d6acb7e
--- /dev/null
+++ b/Logger/ValidationTrait.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Homework\Logger;
+
+/**
+ * Validation trait
+ */
+trait ValidationTrait
+{
+    /**
+     * Validate log message.
+     *
+     * @param string $message
+     *
+     * @return boolean
+     */
+    public function validate(string $message): bool
+    {
+        if (!is_string($message)) {
+            return false;
+        }
+
+        if (mb_check_encoding($message, 'UTF-8') !== true) {
+            return false;
+        }
+
+        if (trim($message) === '') {
+            return false;
+        }
+
+        return true;
+    }
+}
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..b261577
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,22 @@
+{
+    "name": "catsand/homework",
+    "description": "Test task for Mobily",
+    "type": "project",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "catsAND",
+            "email": "cv@left.lv"
+        }
+    ],
+    "autoload": {
+        "psr-4": {"Homework\\": "./"}
+    },
+    "require": {
+        "php": "^8.1",
+        "ext-mbstring": "*"
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^9.5"
+    }
+}
diff --git a/index.php b/index.php
index 7ca24c8..b9ba23c 100644
--- a/index.php
+++ b/index.php
@@ -3,6 +3,9 @@
 require_once 'Logger.php';
 
 
+// Do not change this file
+
+
 function process()
 {
     for ($i = 0; $i < 3; $i++) {
diff --git a/tests/FileHandlerTest.php b/tests/FileHandlerTest.php
new file mode 100644
index 0000000..6f28ebe
--- /dev/null
+++ b/tests/FileHandlerTest.php
@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+require __DIR__ . '/../vendor/autoload.php';
+
+use PHPUnit\Framework\TestCase;
+use Homework\Logger\FileHandler;
+use Homework\Logger\Status;
+
+class FileHandlerTest extends TestCase
+{
+    private const FILE_PATH = __DIR__ . '/../application.log';
+
+    private FileHandler $fileHandler;
+    private string $fileContent;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->fileHandler = new FileHandler();
+        $this->fileContent = file_get_contents(self::FILE_PATH);
+    }
+
+    protected function tearDown(): void
+    {
+        parent::tearDown();
+
+        unset($this->fileHandler);
+        unset($this->fileContent);
+    }
+
+    public function testLogSuccess(): void
+    {
+        $this->assertTrue($this->fileHandler->log(Status::SUCCESS, 'Test success'));
+        $this->assertStringEqualsFile(self::FILE_PATH, $this->fileContent . "Success: Test success\n");
+    }
+
+    public function testLogError(): void
+    {
+        $this->assertTrue($this->fileHandler->log(Status::ERROR, 'Test error'));
+        $this->assertStringEqualsFile(self::FILE_PATH, $this->fileContent . "Error: Test error\n");
+    }
+
+    public function testLogWithEmptyMessage(): void
+    {
+        $this->assertFalse($this->fileHandler->log(Status::SUCCESS, ''));
+        $this->assertStringEqualsFile(self::FILE_PATH, $this->fileContent);
+    }
+
+    public function testLogFileWritable(): void
+    {
+        $this->assertFileIsWritable(self::FILE_PATH);
+    }
+}
diff --git a/tests/HandlerFactoryTest.php b/tests/HandlerFactoryTest.php
new file mode 100644
index 0000000..eb69ed8
--- /dev/null
+++ b/tests/HandlerFactoryTest.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+require __DIR__ . '/../vendor/autoload.php';
+
+use PHPUnit\Framework\TestCase;
+use Homework\Logger\HandlerFactory;
+use Homework\Logger\Type;
+
+class HandlerFactoryTest extends TestCase
+{
+    public function testFileHandler(): void
+    {
+        $instance = HandlerFactory::get(Type::FILE);
+
+        $this->assertInstanceOf('Homework\Logger\FileHandler', $instance);
+        $this->assertInstanceOf('Homework\Logger\HandlerInterface', $instance);
+        $this->assertInstanceOf('Homework\Logger\AbstractHandler', $instance);
+    }
+
+    public function testConsoleHandler(): void
+    {
+        $instance = HandlerFactory::get(Type::CONSOLE);
+
+        $this->assertInstanceOf('Homework\Logger\ConsoleHandler', $instance);
+        $this->assertInstanceOf('Homework\Logger\HandlerInterface', $instance);
+        $this->assertInstanceOf('Homework\Logger\AbstractHandler', $instance);
+    }
+}
diff --git a/tests/LoggerTest.php b/tests/LoggerTest.php
new file mode 100644
index 0000000..1465f98
--- /dev/null
+++ b/tests/LoggerTest.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+require __DIR__ . '/../vendor/autoload.php';
+require __DIR__ . '/../Logger.php';
+
+use PHPUnit\Framework\TestCase;
+
+class LoggerTest extends TestCase
+{
+    public function testGet(): void
+    {
+        $instance = \Logger::get();
+
+        $this->assertInstanceOf('Homework\Logger\FileHandler', $instance);
+        $this->assertInstanceOf('Homework\Logger\HandlerInterface', $instance);
+        $this->assertInstanceOf('Homework\Logger\AbstractHandler', $instance);
+    }
+}
diff --git a/tests/ValidationTraitTest.php b/tests/ValidationTraitTest.php
new file mode 100644
index 0000000..e3c4519
--- /dev/null
+++ b/tests/ValidationTraitTest.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+require __DIR__ . '/../vendor/autoload.php';
+
+use PHPUnit\Framework\TestCase;
+use Homework\Logger\ValidationTrait;
+
+class ValidationTraitTest extends TestCase
+{
+    private $validationTrait;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->validationTrait = $this->getMockForTrait(ValidationTrait::class);
+    }
+
+    protected function tearDown(): void
+    {
+        parent::tearDown();
+
+        unset($this->validationTrait);
+    }
+
+    /**
+     * @dataProvider validationProvider
+     */
+    public function testValidate($message, $result): void
+    {
+        $this->assertSame($this->validationTrait->validate($message), $result);
+    }
+
+    public function validationProvider(): array
+    {
+        $data =  [
+            ['test', true],
+            ['🔰', true],
+            ["\xd1", false], // Test broken UTF-8
+            ['', false]
+        ];
+
+        return $data;
+    }
+}