init

ink/terminal-focus-state.ts

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+// Terminal focus state signal — non-React access to DECSET 1004 focus events.
+// 'unknown' is the default for terminals that don't support focus reporting;
+// consumers treat 'unknown' identically to 'focused' (no throttling).
+// Subscribers are notified synchronously when focus changes, used by
+// TerminalFocusProvider to avoid polling.
+export type TerminalFocusState = 'focused' | 'blurred' | 'unknown'
+
+let focusState: TerminalFocusState = 'unknown'
+const resolvers: Set<() => void> = new Set()
+const subscribers: Set<() => void> = new Set()
+
+export function setTerminalFocused(v: boolean): void {
+  focusState = v ? 'focused' : 'blurred'
+  // Notify useSyncExternalStore subscribers
+  for (const cb of subscribers) {
+    cb()
+  }
+  if (!v) {
+    for (const resolve of resolvers) {
+      resolve()
+    }
+    resolvers.clear()
+  }
+}
+
+export function getTerminalFocused(): boolean {
+  return focusState !== 'blurred'
+}
+
+export function getTerminalFocusState(): TerminalFocusState {
+  return focusState
+}
+
+// For useSyncExternalStore
+export function subscribeTerminalFocus(cb: () => void): () => void {
+  subscribers.add(cb)
+  return () => {
+    subscribers.delete(cb)
+  }
+}
+
+export function resetTerminalFocusState(): void {
+  focusState = 'unknown'
+  for (const cb of subscribers) {
+    cb()
+  }
+}