compound joysticks, button guide in screens, improve API

src/main/java/dev/isxander/controlify/controller/joystick/CompoundJoystickInfo.java

@@ -0,0 +1,46 @@
+package dev.isxander.controlify.controller.joystick;
+
+import dev.isxander.controlify.controller.Controller;
+import dev.isxander.controlify.controller.ControllerType;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Optional;
+
+public record CompoundJoystickInfo(Collection<String> joystickUids, String friendlyName) {
+    public ControllerType type() {
+        return new ControllerType(friendlyName, createUID(joystickUids));
+    }
+
+    public boolean canBeUsed() {
+        List<Controller<?, ?>> joysticks = Controller.CONTROLLERS.values().stream().filter(c -> joystickUids.contains(c.uid())).toList();
+        if (joysticks.size() != joystickUids().size()) {
+            return false; // not all controllers are connected
+        }
+        if (joysticks.stream().anyMatch(c -> !c.canBeUsed())) {
+            return false; // not all controllers can be used
+        }
+
+        return true;
+    }
+
+    public boolean isLoaded() {
+        return Controller.CONTROLLERS.containsKey(createUID(joystickUids));
+    }
+
+    public Optional<CompoundJoystickController> attemptCreate() {
+        if (!canBeUsed()) return Optional.empty();
+
+        List<Integer> joystickIDs = Controller.CONTROLLERS.values().stream()
+                .filter(c -> joystickUids.contains(c.uid()))
+                .map(Controller::joystickId)
+                .toList();
+
+        ControllerType type = type();
+        return Optional.of(new CompoundJoystickController(joystickIDs, type.identifier(), type));
+    }
+
+    public static String createUID(Collection<String> joystickUIDs) {
+        return "compound-" + String.join("_", joystickUIDs);
+    }
+}