[Init] Initial commit - NetMesh terminal manager

application/state/windowOpacitySync.ts

@@ -0,0 +1,88 @@
+import {
+  DEFAULT_WINDOW_OPACITY,
+  clampWindowOpacity,
+} from './settingsStateDefaults';
+
+export { DEFAULT_WINDOW_OPACITY, clampWindowOpacity };
+
+export type WindowOpacityMutationSource = 'local' | 'incoming';
+
+export type WindowOpacityRecord = {
+  opacity: number;
+  version: number;
+};
+
+/**
+ * Parse persisted / IPC window-opacity payloads.
+ * Accepts legacy plain numbers ("0.85") and versioned records.
+ */
+export function parseWindowOpacityRecord(raw: unknown): WindowOpacityRecord {
+  if (typeof raw === 'number' || typeof raw === 'string') {
+    const trimmed = typeof raw === 'string' ? raw.trim() : raw;
+    // Prefer JSON object payloads written by serializeWindowOpacityRecord.
+    if (typeof trimmed === 'string' && trimmed.startsWith('{')) {
+      try {
+        return parseWindowOpacityRecord(JSON.parse(trimmed));
+      } catch {
+        // fall through to Number()
+      }
+    }
+    const asNumber = Number(trimmed);
+    if (Number.isFinite(asNumber)) {
+      return { opacity: clampWindowOpacity(asNumber), version: 0 };
+    }
+  }
+
+  if (raw && typeof raw === 'object') {
+    const record = raw as { opacity?: unknown; version?: unknown };
+    const opacity = clampWindowOpacity(record.opacity);
+    const version = Number(record.version);
+    return {
+      opacity,
+      version: Number.isFinite(version) && version > 0 ? Math.floor(version) : 0,
+    };
+  }
+
+  return { opacity: DEFAULT_WINDOW_OPACITY, version: 0 };
+}
+
+export function serializeWindowOpacityRecord(record: WindowOpacityRecord): string {
+  return JSON.stringify({
+    opacity: clampWindowOpacity(record.opacity),
+    version: Math.max(0, Math.floor(record.version) || 0),
+  });
+}
+
+/**
+ * Incoming peer updates must not clobber a newer local/drag revision.
+ * Equal versions are treated as already-applied (no state thrash).
+ */
+export function shouldApplyWindowOpacityRecord(
+  current: WindowOpacityRecord,
+  incoming: WindowOpacityRecord,
+): boolean {
+  if (incoming.version > current.version) return true;
+  if (incoming.version < current.version) return false;
+  // Same version: only apply when the opacity itself differs and both are
+  // legacy/unversioned (version 0), so first-load plain strings still sync.
+  if (incoming.version === 0 && current.version === 0) {
+    return incoming.opacity !== current.opacity;
+  }
+  return false;
+}
+
+/**
+ * Decide whether a window-opacity state change should be rebroadcast to peer
+ * windows. Incoming IPC/storage updates must not notify again — otherwise a
+ * fast slider drag in the settings window ping-pongs with the main window and
+ * the controlled range input oscillates (see #2018).
+ */
+export function shouldBroadcastWindowOpacityChange(
+  mutationSource: WindowOpacityMutationSource,
+  persistMounted: boolean,
+): { shouldBroadcast: boolean; nextSource: WindowOpacityMutationSource } {
+  if (mutationSource === 'incoming') {
+    return { shouldBroadcast: false, nextSource: 'local' };
+  }
+  return { shouldBroadcast: persistMounted, nextSource: 'local' };
+}