feat: freeze-duration prompt

Freeze frame now asks for the duration (decimal seconds, 0 < d <= 600)
before capture, via a promise-based zustand store mounted as an
editor-global dialog. Last-used duration persists and prefills. Cancel
aborts before capture with no commands.

1 files changed, 72 insertions, 0 deletions

diff --git a/apps/web/src/actions/freeze-frame-store.ts b/apps/web/src/actions/freeze-frame-store.ts
new file mode 100644
index 00000000..17102780
--- /dev/null
+++ b/apps/web/src/actions/freeze-frame-store.ts
@@ -0,0 +1,72 @@
+"use client";
+
+import { create } from "zustand";
+import { persist } from "zustand/middleware";
+
+export const DEFAULT_FREEZE_DURATION_SECONDS = 3;
+export const MAX_FREEZE_DURATION_SECONDS = 600;
+
+export function isValidFreezeDuration({
+	seconds,
+}: {
+	seconds: number;
+}): boolean {
+	return (
+		Number.isFinite(seconds) &&
+		seconds > 0 &&
+		seconds <= MAX_FREEZE_DURATION_SECONDS
+	);
+}
+
+type DurationResolver = ({ seconds }: { seconds: number | null }) => void;
+
+interface FreezeFrameState {
+	isOpen: boolean;
+	lastDurationSeconds: number;
+	resolver: DurationResolver | null;
+	requestDuration: () => Promise<number | null>;
+	confirmDuration: ({ seconds }: { seconds: number }) => void;
+	cancelDuration: () => void;
+}
+
+export const useFreezeFrameStore = create<FreezeFrameState>()(
+	persist(
+		(set, get) => ({
+			isOpen: false,
+			lastDurationSeconds: DEFAULT_FREEZE_DURATION_SECONDS,
+			resolver: null,
+
+			requestDuration: () =>
+				new Promise<number | null>((resolve) => {
+					// A new invocation supersedes any pending one: resolve it as
+					// cancelled so its handler aborts instead of hanging.
+					get().resolver?.({ seconds: null });
+					set({
+						isOpen: true,
+						resolver: ({ seconds }) => resolve(seconds),
+					});
+				}),
+			confirmDuration: ({ seconds }) => {
+				if (!isValidFreezeDuration({ seconds })) {
+					return;
+				}
+				get().resolver?.({ seconds });
+				set({
+					isOpen: false,
+					resolver: null,
+					lastDurationSeconds: seconds,
+				});
+			},
+			cancelDuration: () => {
+				get().resolver?.({ seconds: null });
+				set({ isOpen: false, resolver: null });
+			},
+		}),
+		{
+			name: "freeze-frame-store",
+			partialize: (state) => ({
+				lastDurationSeconds: state.lastDurationSeconds,
+			}),
+		},
+	),
+);