initial state: muzick music player + recommendation engine

frontend/src/store/useVibeStore.ts

@@ -0,0 +1,53 @@
+import { create } from 'zustand';
+import type { Track, VibeSession } from '../types';
+
+// V2 recommendation session state. The backend stores the plan in Redis
+// (keyed by sessionId) and serves tracks one at a time via GET /v2/vibe/next.
+// We keep a lookahead buffer of upcoming Track[] to feed playback.
+interface VibeState {
+  activeSessionId: string | null;
+  seedTrackId: string | null;
+  centerTrack: Track | null;
+  buffer: Track[]; // lookahead buffer of upcoming recommended tracks
+
+  setActiveSession: (session: VibeSession | null) => void;
+  setSeedTrackId: (seedTrackId: string | null) => void;
+  setCenterTrack: (track: Track | null) => void;
+  setBuffer: (buffer: Track[]) => void;
+  appendBuffer: (tracks: Track[]) => void;
+  shiftBuffer: () => Track | undefined;
+  reset: () => void;
+}
+
+const initialState = {
+  activeSessionId: null as string | null,
+  seedTrackId: null as string | null,
+  centerTrack: null as Track | null,
+  buffer: [] as Track[],
+};
+
+export const useVibeStore = create<VibeState>((set, get) => ({
+  ...initialState,
+
+  setActiveSession: (session) =>
+    set(
+      session
+        ? { activeSessionId: session.sessionId, seedTrackId: session.seedTrackId }
+        : { activeSessionId: null, seedTrackId: null }
+    ),
+
+  setSeedTrackId: (seedTrackId) => set({ seedTrackId }),
+  setCenterTrack: (centerTrack) => set({ centerTrack }),
+  setBuffer: (buffer) => set({ buffer }),
+  appendBuffer: (tracks) => set((state) => ({ buffer: [...state.buffer, ...tracks] })),
+
+  shiftBuffer: () => {
+    const { buffer } = get();
+    if (buffer.length === 0) return undefined;
+    const [head, ...rest] = buffer;
+    set({ buffer: rest });
+    return head;
+  },
+
+  reset: () => set({ ...initialState }),
+}));