feat(notifications): add overlay notifications with position config (#110)

src/main/runtime/overlay-loading-osd.ts

@@ -0,0 +1,49 @@
+const DEFAULT_OVERLAY_LOADING_OSD_TICK_MS = 180;
+const OVERLAY_LOADING_OSD_FRAMES = ['|', '/', '-', '\\'] as const;
+
+export function createOverlayLoadingOsdController(deps: {
+  showOsd: (message: string) => void;
+  clearOsd: () => void;
+  setInterval?: (callback: () => void, delayMs: number) => unknown;
+  clearInterval?: (timer: unknown) => void;
+}) {
+  const setIntervalHandler =
+    deps.setInterval ??
+    ((callback: () => void, delayMs: number): unknown => setInterval(callback, delayMs));
+  const clearIntervalHandler =
+    deps.clearInterval ??
+    ((timer: unknown): void => clearInterval(timer as ReturnType<typeof setInterval>));
+  let active = false;
+  let frame = 0;
+  let timer: unknown = null;
+
+  const showNextFrame = (): void => {
+    deps.showOsd(
+      `Overlay loading ${OVERLAY_LOADING_OSD_FRAMES[frame % OVERLAY_LOADING_OSD_FRAMES.length]}`,
+    );
+    frame += 1;
+  };
+
+  return {
+    start(): void {
+      if (active) {
+        return;
+      }
+      active = true;
+      frame = 0;
+      showNextFrame();
+      timer = setIntervalHandler(showNextFrame, DEFAULT_OVERLAY_LOADING_OSD_TICK_MS);
+    },
+    stop(): void {
+      if (!active) {
+        return;
+      }
+      active = false;
+      if (timer !== null) {
+        clearIntervalHandler(timer);
+        timer = null;
+      }
+      deps.clearOsd();
+    },
+  };
+}