diff --git a/bin/php-class-diagram b/bin/php-class-diagram
index 505bf1c..6bbe0b5 100755
--- a/bin/php-class-diagram
+++ b/bin/php-class-diagram
@@ -1,15 +1,23 @@
 #!/usr/bin/env php
 <?php declare(strict_types=1);
+
 namespace Smeghead\PhpClassDiagram;
 
-foreach ([__DIR__ . '/../../../autoload.php', __DIR__ . '/../vendor/autoload.php'] as $file) {
+use Smeghead\PhpClassDiagram\Config\Options;
+
+foreach (
+    [
+        __DIR__ . '/../../../autoload.php',
+        __DIR__ . '/../vendor/autoload.php'
+    ] as $file
+) {
     if (file_exists($file)) {
         require $file;
         break;
     }
 }
 
-$options = getopt('hv',[
+$options = getopt('hv', [
     'help',
     'version',
     'class-diagram',
@@ -31,7 +39,7 @@ $options = getopt('hv',[
 ], $rest_index);
 $arguments = array_slice($argv, $rest_index);
 
-$usage =<<<EOS
+$usage = <<<EOS
 usage: php-class-diagram [OPTIONS] <target php source directory>
 
 A CLI tool that parses the PHP source directory and generates PlantUML class diagram scripts as output.
@@ -60,27 +68,25 @@ OPTIONS
 EOS;
 
 if (isset($options['v']) || isset($options['version'])) {
-    fputs(STDERR, sprintf('php-class-diagram %s%s', \Smeghead\PhpClassDiagram\Main::VERSION, PHP_EOL));
+    fwrite(STDERR, sprintf('php-class-diagram %s%s', Main::VERSION, PHP_EOL));
     exit(-1);
 }
 if (isset($options['h']) || isset($options['help'])) {
-    fputs(STDERR, $usage);
+    fwrite(STDERR, $usage);
     exit(-1);
 }
 
 $directory = array_shift($arguments);
 if (empty($directory)) {
-    fputs(STDERR, "ERROR: not specified php source file.\n");
-    fputs(STDERR, $usage);
+    fwrite(STDERR, "ERROR: not specified php source file.\n");
+    fwrite(STDERR, $usage);
     exit(-1);
 }
-if ( ! is_dir($directory)) {
-    fputs(STDERR, sprintf("ERROR: specified directory dose not exists. directory: %s\n", $directory));
-    fputs(STDERR, $usage);
+if (!is_dir($directory)) {
+    fwrite(STDERR, sprintf("ERROR: specified directory dose not exists. directory: %s\n", $directory));
+    fwrite(STDERR, $usage);
     exit(-1);
 }
 
-use Smeghead\PhpClassDiagram\Config\Options;
-use Smeghead\PhpClassDiagram\Main;
-
-new Main($directory, new Options($options));
+$main = new Main($directory, new Options($options));
+$main->run();
diff --git a/src/Config/Options.php b/src/Config/Options.php
index a26e963..86a9d4a 100644
--- a/src/Config/Options.php
+++ b/src/Config/Options.php
@@ -16,7 +16,7 @@ final class Options
     public const DIAGRAM_CLASS = 'class';
     public const DIAGRAM_PACKAGE = 'package';
     public const DIAGRAM_JIG = 'jig';
-    public const DIAGRAM_DIVSION = 'division';
+    public const DIAGRAM_DIVISION = 'division';
 
     /**
      * @param array<string, mixed> $opt Option array
@@ -49,7 +49,7 @@ public function diagram(): string
             return self::DIAGRAM_JIG;
         }
         if (isset($this->opt['division-diagram'])) {
-            return self::DIAGRAM_DIVSION;
+            return self::DIAGRAM_DIVISION;
         }
         // default
         return self::DIAGRAM_CLASS;
diff --git a/src/Main.php b/src/Main.php
index fb7ea5f..305a2ad 100644
--- a/src/Main.php
+++ b/src/Main.php
@@ -4,56 +4,102 @@
 
 namespace Smeghead\PhpClassDiagram;
 
-use Symfony\Component\Finder\Finder;
+use RuntimeException;
 use Smeghead\PhpClassDiagram\Config\Options;
-use Smeghead\PhpClassDiagram\DiagramElement\{
-    Entry,
-    Relation,
-};
+use Smeghead\PhpClassDiagram\DiagramElement\Entry;
+use Smeghead\PhpClassDiagram\DiagramElement\Relation;
 use Smeghead\PhpClassDiagram\Php\PhpReader;
+use Symfony\Component\Finder\Finder;
 
 final class Main
 {
-    const VERSION = 'v1.3.0';
+    public const VERSION = 'v1.3.0';
+
+    public function __construct(
+        private string $directory,
+        private Options $options,
+    ) {
+    }
 
-    public function __construct(string $directory, Options $options)
+    public function run(): void
+    {
+        $finder = $this->createFinder();
+        $entries = $this->findEntries($finder);
+        $this->renderEntries($entries);
+    }
+
+    private function createFinder(): Finder
     {
         $finder = new Finder();
-        $finder->files()->in($directory);
-        $finder->files()->name($options->includes());
-        $excludes = $options->excludes();
+        $finder->files()->in($this->directory);
+        $finder->files()->name($this->options->includes());
+        $excludes = $this->options->excludes();
+
         if (count($excludes) > 0) {
             $finder->files()->notName($excludes)->notPath($excludes);
         }
+
+        return $finder;
+    }
+
+    /**
+     * @return list<Entry>
+     */
+    private function findEntries(Finder $finder): array
+    {
         $entries = [];
         foreach ($finder as $file) {
             try {
-                $reflections = PhpReader::parseFile(realpath($directory), $file->getRealPath(), $options);
+                $reflections = PhpReader::parseFile(
+                    realpath($this->directory),
+                    $file->getRealPath(),
+                    $this->options
+                );
                 foreach ($reflections as $reflection) {
-                    $entries[] = new Entry($file->getRelativePath(), $reflection->getInfo(), $options);
+                    $entries[] = new Entry($file->getRelativePath(), $reflection->getInfo(), $this->options);
                 }
             } catch (\Exception $e) {
-                fputs(STDERR, $e->getMessage() . "\r\n");
+                fwrite(STDERR, $e->getMessage() . "\r\n");
             }
         }
-        $relation = new Relation($entries, $options);
-        switch ($options->diagram()) {
-            case Options::DIAGRAM_CLASS:
-                echo implode("\r\n", $relation->dump()) . "\r\n";
-                break;
-            case OPTIONS::DIAGRAM_PACKAGE:
-                echo implode("\r\n", $relation->dumpPackages()) . "\r\n";
-                break;
-            case OPTIONS::DIAGRAM_JIG:
-                echo implode("\r\n", $relation->dump()) . "\r\n";
-                echo implode("\r\n", $relation->dumpPackages()) . "\r\n";
-                echo implode("\r\n", $relation->dumpDivisions()) . "\r\n";
-                break;
-            case OPTIONS::DIAGRAM_DIVSION:
-                echo implode("\r\n", $relation->dumpDivisions()) . "\r\n";
-                break;
-            default:
-                throw new \Exception('invalid diagram.');
-        }
+        return $entries;
+    }
+
+    /**
+     * @param list<Entry> $entries
+     */
+    private function renderEntries(array $entries): void
+    {
+        $relation = new Relation($entries, $this->options);
+
+        match ($this->options->diagram()) {
+            Options::DIAGRAM_CLASS => $this->renderDiagramClass($relation),
+            OPTIONS::DIAGRAM_PACKAGE => $this->renderDiagramPackage($relation),
+            OPTIONS::DIAGRAM_JIG => $this->renderDiagramJig($relation),
+            OPTIONS::DIAGRAM_DIVISION => $this->renderDiagramDivision($relation),
+            default => throw new RuntimeException('invalid diagram.')
+        };
+    }
+
+    private function renderDiagramClass(Relation $relation): void
+    {
+        echo implode("\r\n", $relation->dump()) . "\r\n";
+    }
+
+    private function renderDiagramPackage(Relation $relation): void
+    {
+        echo implode("\r\n", $relation->dumpPackages()) . "\r\n";
+    }
+
+    private function renderDiagramJig(Relation $relation): void
+    {
+        echo implode("\r\n", $relation->dump()) . "\r\n";
+        echo implode("\r\n", $relation->dumpPackages()) . "\r\n";
+        echo implode("\r\n", $relation->dumpDivisions()) . "\r\n";
+    }
+
+    private function renderDiagramDivision(Relation $relation): void
+    {
+        echo implode("\r\n", $relation->dumpDivisions()) . "\r\n";
     }
 }
diff --git a/test/OptionsTest.php b/test/OptionsTest.php
index f7b6ad4..f2770e1 100644
--- a/test/OptionsTest.php
+++ b/test/OptionsTest.php
@@ -178,7 +178,7 @@ public function testDiagram_division(): void
 
         $options = new Options($opt);
 
-        $this->assertSame(Options::DIAGRAM_DIVSION, $options->diagram(), 'diagram is division.');
+        $this->assertSame(Options::DIAGRAM_DIVISION, $options->diagram(), 'diagram is division.');
     }
     public function testDiagram3(): void
     {