import AsyncStorage from "@react-native-async-storage/async-storage";
import { create } from "zustand";
import { createJSONStorage, persist } from "zustand/middleware";

export type NotificationKind =
  | "order"
  | "rx"
  | "dose"
  | "loyalty"
  | "promo"
  | "system";

export type AppNotification = {
  id: string;
  kind: NotificationKind;
  title: string;
  body: string;
  createdAt: string;
  read: boolean;
  /** Deep-link target inside the app */
  href?: string | null;
};

type NotificationState = {
  items: AppNotification[];
  unreadCount: () => number;
  markRead: (id: string) => void;
  markAllRead: () => void;
  remove: (id: string) => void;
  push: (
    n: Omit<AppNotification, "id" | "createdAt" | "read"> & {
      id?: string;
      createdAt?: string;
      read?: boolean;
    }
  ) => AppNotification;
};

function hoursAgo(n: number) {
  const d = new Date();
  d.setHours(d.getHours() - n);
  return d.toISOString();
}

export const seedNotifications: AppNotification[] = [
  {
    id: "ntf_dose_1",
    kind: "dose",
    title: "Time for Metformin 500mg",
    body: "Confirm your 20:00 dose or snooze for 10 minutes.",
    createdAt: hoursAgo(1),
    read: false,
    href: "/(root)/(screens)/prescription/calendar/rx_demo_metformin",
  },
  {
    id: "ntf_rx_1",
    kind: "rx",
    title: "Prescription under review",
    body: "A pharmacist is checking your Azithromycin Rx. We’ll notify you when it’s ready.",
    createdAt: hoursAgo(5),
    read: false,
    href: "/(root)/(screens)/prescription/rx_demo_azitro",
  },
  {
    id: "ntf_order_1",
    kind: "order",
    title: "Rider is on the way",
    body: "Your Bole delivery is out for delivery. Track live progress anytime.",
    createdAt: hoursAgo(8),
    read: false,
    href: "/(root)/(screens)/tracking/ord_demo_active",
  },
  {
    id: "ntf_loyalty_1",
    kind: "loyalty",
    title: "120 points ready to redeem",
    body: "Redeem 100 pts for voucher GISHEN10 at checkout.",
    createdAt: hoursAgo(26),
    read: true,
    href: "/(root)/(screens)/loyalty",
  },
  {
    id: "ntf_promo_1",
    kind: "promo",
    title: "Weekend wellness picks",
    body: "Save on vitamins and personal care this week at any Gishen branch.",
    createdAt: hoursAgo(40),
    read: true,
    href: "/(root)/(screens)/shop",
  },
  {
    id: "ntf_system_1",
    kind: "system",
    title: "Guest pickup tip",
    body: "Shopping as a guest? Use your quick pickup code at any branch counter.",
    createdAt: hoursAgo(72),
    read: true,
    href: null,
  },
];

export const useNotificationStore = create<NotificationState>()(
  persist(
    (set, get) => ({
      items: seedNotifications,
      unreadCount: () => get().items.filter((n) => !n.read).length,
      markRead: (id) =>
        set({
          items: get().items.map((n) => (n.id === id ? { ...n, read: true } : n)),
        }),
      markAllRead: () =>
        set({ items: get().items.map((n) => ({ ...n, read: true })) }),
      remove: (id) => set({ items: get().items.filter((n) => n.id !== id) }),
      push: (payload) => {
        const item: AppNotification = {
          id: payload.id ?? `ntf_${Date.now()}`,
          createdAt: payload.createdAt ?? new Date().toISOString(),
          read: payload.read ?? false,
          kind: payload.kind,
          title: payload.title,
          body: payload.body,
          href: payload.href ?? null,
        };
        set({ items: [item, ...get().items] });
        return item;
      },
    }),
    {
      name: "gishen-notifications",
      storage: createJSONStorage(() => AsyncStorage),
      version: 1,
      migrate: (persisted: unknown) => {
        const state = (persisted ?? {}) as Partial<NotificationState>;
        if (!state.items?.length) {
          return { ...state, items: seedNotifications };
        }
        return state;
      },
    }
  )
);