commons: add OS tool

convention/src/main/kotlin/io/gitlab/jfronny/scripts/OS.kt

@@ -0,0 +1,20 @@
+package io.gitlab.jfronny.scripts
+
+object OS {
+    val TYPE: Type = with(System.getProperty("os.name", "generic").toLowerCase()) {
+        when {
+            contains("mac") || contains("darwin") -> Type.MAC_OS
+            contains("win") -> Type.WINDOWS
+            contains("nux") -> Type.LINUX
+            else -> throw UnsupportedOSException()
+        }
+    }
+
+    enum class Type(val displayName: String, val codename: String) {
+        WINDOWS("Windows", "windows"),
+        MAC_OS("OSX", "macos"),
+        LINUX("Linux", "linux");
+    }
+
+    class UnsupportedOSException() : RuntimeException("Unrecognized OS")
+}