ability to override server.conf with java -D arguments

AndroidCompat/Config/src/main/java/xyz/nulldev/ts/config/ConfigModule.kt

@@ -1,8 +1,40 @@
 package xyz.nulldev.ts.config
 
+/*
+ * Copyright (C) Contributors to the Suwayomi project
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
 import com.typesafe.config.Config
+import io.github.config4k.getValue
+import kotlin.reflect.KProperty
 
 /**
  * Abstract config module.
  */
-abstract class ConfigModule(config: Config)
+abstract class ConfigModule(config: Config, moduleName: String = "") {
+    val overridableWithSysProperty = SystemPropertyOverrideDelegate(config, moduleName)
+}
+
+class SystemPropertyOverrideDelegate(val config: Config, val moduleName: String) {
+    inline operator fun <R, reified T> getValue(thisRef: R, property: KProperty<*>): T {
+        val configValue: T = config.getValue(thisRef, property)
+
+        println("getting " + "suwayomi.tachidesk.config.$moduleName.${property.name}")
+        val combined = System.getProperty(
+            "suwayomi.tachidesk.config.$moduleName.${property.name}",
+            configValue.toString()
+        )
+
+        val asT = when(T::class.simpleName) {
+            "Int" -> combined.toInt()
+            "Boolean" -> combined.toBoolean()
+            // add more types as needed
+            else -> combined
+        }
+
+        return asT as T
+    }
+}