init filesystem model

src/Model/Filesystem.php

@@ -0,0 +1,98 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yggverse\Yoda\Model;
+
+class Filesystem
+{
+    private string $_base;
+
+    public function __construct(
+        string $dirname
+    ) {
+        // Unify separators
+        $filename = self::_fixDirectorySeparators(
+            $dirname
+        );
+
+        // Require path
+        if (empty($dirname))
+        {
+            throw new \Exception;
+        }
+
+        // Require absolute path
+        if (!str_starts_with($dirname, DIRECTORY_SEPARATOR))
+        {
+            throw new \Exception;
+        }
+
+        // Init destination
+        if (!is_dir($dirname))
+        {
+            mkdir(
+                $dirname,
+                0775,
+                true
+            );
+        }
+
+        // Define filesystem base ending with slash
+        $this->_base = realpath(
+            $dirname
+        ) . DIRECTORY_SEPARATOR;
+    }
+
+    public function getBase(): string
+    {
+        return $this->_base;
+    }
+
+    public function getAbsolute(
+        string $filename
+    ): ?string
+    {
+        // Require filename
+        if (empty($filename))
+        {
+            throw new \Exception;
+        }
+
+        // Unify separators
+        $filename = self::_fixDirectorySeparators(
+            $filename
+        );
+
+        // Check filename is absolute
+        if (str_starts_with($filename, DIRECTORY_SEPARATOR))
+        {
+            // Check absolute filename path started with filesystem base
+            if (!str_starts_with($filepath, $this->_base))
+            {
+                throw new \Exception;
+            }
+
+            // Return as is
+            return $filename;
+        }
+
+        // Append base
+        return $this->_base . $filename;
+    }
+
+    private static function _fixDirectorySeparators(
+        string $path,
+        string $separator = DIRECTORY_SEPARATOR
+    ): string
+    {
+        return str_replace(
+            [
+                '/',
+                '\\' // win
+            ],
+            $separator,
+            $path
+        );
+    }
+}