From e34d2471c3348ee97083e2c130d61e3a0c606741 Mon Sep 17 00:00:00 2001
From: Leo Vasanko <git@vasanko.com>
Date: Mon, 4 May 2026 00:51:52 +0000
Subject: [PATCH] Add gamepad navigation

---
 .../src/composables/useGamepadNavigation.ts   | 123 ++++++++++++++++++
 frontend/src/main.ts                          |   2 +
 2 files changed, 125 insertions(+)
 create mode 100644 frontend/src/composables/useGamepadNavigation.ts

diff --git a/frontend/src/composables/useGamepadNavigation.ts b/frontend/src/composables/useGamepadNavigation.ts
new file mode 100644
index 0000000..5cba3cf
--- /dev/null
+++ b/frontend/src/composables/useGamepadNavigation.ts
@@ -0,0 +1,123 @@
+type GamepadAction = 'up' | 'down' | 'left' | 'right' | 'select' | 'back';
+
+const GAMEPAD_AXIS_THRESHOLD = 0.55;
+const GAMEPAD_REPEAT_MS = 180;
+
+const KEY_BY_ACTION: Record<GamepadAction, string> = {
+  up: 'ArrowUp',
+  down: 'ArrowDown',
+  left: 'ArrowLeft',
+  right: 'ArrowRight',
+  select: 'Enter',
+  back: 'Escape',
+};
+
+const gamepadPressedState: Record<GamepadAction, boolean> = {
+  up: false,
+  down: false,
+  left: false,
+  right: false,
+  select: false,
+  back: false,
+};
+
+const gamepadLastTriggerAt: Record<GamepadAction, number> = {
+  up: 0,
+  down: 0,
+  left: 0,
+  right: 0,
+  select: 0,
+  back: 0,
+};
+
+let gamepadFrameId: number | null = null;
+let gamepadInstalled = false;
+
+function dispatchKey(key: string) {
+  const active = document.activeElement;
+  const target = active instanceof HTMLElement ? active : document;
+  target.dispatchEvent(new KeyboardEvent('keydown', {
+    key,
+    bubbles: true,
+    cancelable: true,
+  }));
+}
+
+function applyGamepadAction(action: GamepadAction, isPressed: boolean, now: number) {
+  const wasPressed = gamepadPressedState[action];
+  gamepadPressedState[action] = isPressed;
+
+  if (!isPressed) return;
+
+  const shouldRepeat = action === 'up' || action === 'down' || action === 'left' || action === 'right';
+  const canTrigger = !wasPressed || (shouldRepeat && now - gamepadLastTriggerAt[action] >= GAMEPAD_REPEAT_MS);
+  if (!canTrigger) return;
+
+  gamepadLastTriggerAt[action] = now;
+  dispatchKey(KEY_BY_ACTION[action]);
+}
+
+function resetPressedState() {
+  gamepadPressedState.up = false;
+  gamepadPressedState.down = false;
+  gamepadPressedState.left = false;
+  gamepadPressedState.right = false;
+  gamepadPressedState.select = false;
+  gamepadPressedState.back = false;
+}
+
+function pollGamepad() {
+  const gamepads = navigator.getGamepads?.() ?? [];
+  const now = performance.now();
+  const connectedGamepads = gamepads.filter((gp): gp is Gamepad => Boolean(gp && gp.connected));
+
+  if (connectedGamepads.length > 0) {
+    let up = false;
+    let down = false;
+    let left = false;
+    let right = false;
+    let select = false;
+    let back = false;
+
+    for (const gamepad of connectedGamepads) {
+      const axisX = gamepad.axes[0] ?? 0;
+      const axisY = gamepad.axes[1] ?? 0;
+
+      up = up || Boolean(gamepad.buttons[12]?.pressed) || axisY <= -GAMEPAD_AXIS_THRESHOLD;
+      down = down || Boolean(gamepad.buttons[13]?.pressed) || axisY >= GAMEPAD_AXIS_THRESHOLD;
+      left = left || Boolean(gamepad.buttons[14]?.pressed) || axisX <= -GAMEPAD_AXIS_THRESHOLD;
+      right = right || Boolean(gamepad.buttons[15]?.pressed) || axisX >= GAMEPAD_AXIS_THRESHOLD;
+
+      // Xbox mapping on standard gamepads: A=0, B=1
+      select = select || Boolean(gamepad.buttons[0]?.pressed);
+      back = back || Boolean(gamepad.buttons[1]?.pressed);
+    }
+
+    applyGamepadAction('up', up, now);
+    applyGamepadAction('down', down, now);
+    applyGamepadAction('left', left, now);
+    applyGamepadAction('right', right, now);
+    applyGamepadAction('select', select, now);
+    applyGamepadAction('back', back, now);
+  } else {
+    resetPressedState();
+  }
+
+  gamepadFrameId = window.requestAnimationFrame(pollGamepad);
+}
+
+export function installGamepadNavigation() {
+  if (gamepadInstalled) return;
+  gamepadInstalled = true;
+  gamepadFrameId = window.requestAnimationFrame(pollGamepad);
+}
+
+export function uninstallGamepadNavigation() {
+  if (!gamepadInstalled) return;
+  gamepadInstalled = false;
+  if (gamepadFrameId !== null) {
+    window.cancelAnimationFrame(gamepadFrameId);
+    gamepadFrameId = null;
+  }
+  resetPressedState();
+}
diff --git a/frontend/src/main.ts b/frontend/src/main.ts
index 4b3d0a4..8e5cde2 100644
--- a/frontend/src/main.ts
+++ b/frontend/src/main.ts
@@ -3,8 +3,10 @@ import App from './App.vue'
 import router from './router'
 import './styles/main.css'
 import { installKeyboardNavigation } from './composables/useKeyboardNavigation'
+import { installGamepadNavigation } from './composables/useGamepadNavigation'
 
 // Install global keyboard navigation handlers immediately
 installKeyboardNavigation()
+installGamepadNavigation()
 
 createApp(App).use(router).mount('#app')