import AsyncStorage from "@react-native-async-storage/async-storage";
import { create } from "zustand";
import { createJSONStorage, persist } from "zustand/middleware";
import { seedOrders } from "@/lib/data/seed";
import type { CartItem } from "@/lib/stores/cartStore";
import type { Fulfillment, PaymentMethod } from "@/lib/stores/locationStore";

export type OrderStatus =
  | "requested"
  | "confirmed"
  | "paid"
  | "dispatched"
  | "delivered"
  | "completed"
  | "cancelled";

export type Order = {
  id: string;
  createdAt: string;
  items: CartItem[];
  subtotal: number;
  deliveryFee: number;
  discount: number;
  voucherCode?: string | null;
  total: number;
  fulfillment: Fulfillment;
  branchId?: string | null;
  areaLabel?: string;
  addressId?: string | null;
  addressLine?: string;
  paymentMethod: PaymentMethod;
  status: OrderStatus;
  riderAssigned?: boolean;
  corporateCovered?: number;
  selfPay?: number;
  customerName?: string;
  customerPhone?: string;
  notes?: string;
  /** Guest / pickup QR-style code shown at any branch counter */
  pickupCode?: string | null;
  /** When true, order can be fulfilled at any Gishen branch */
  anyBranch?: boolean;
  isGuestOrder?: boolean;
  timeline?: { at: string; label: string; status: OrderStatus | "created" }[];
};

type OrdersState = {
  orders: Order[];
  addOrder: (
    order: Omit<Order, "id" | "createdAt" | "status" | "timeline" | "discount"> & {
      discount?: number;
      status?: OrderStatus;
    }
  ) => Order;
  updateStatus: (id: string, status: OrderStatus) => void;
  cancelOrder: (id: string) => void;
  getById: (id: string) => Order | undefined;
  getByPickupCode: (code: string) => Order | undefined;
};

function timelineFor(status: OrderStatus, createdAt: string) {
  const steps: Order["timeline"] = [
    { at: createdAt, label: "Order placed", status: "created" },
  ];
  const add = (label: string, s: OrderStatus, hours: number) => {
    const d = new Date(createdAt);
    d.setHours(d.getHours() + hours);
    steps!.push({ at: d.toISOString(), label, status: s });
  };
  if (["confirmed", "paid", "dispatched", "delivered", "completed"].includes(status)) {
    add("Confirmed by pharmacy", "confirmed", 0.2);
  }
  if (["paid", "dispatched", "delivered", "completed"].includes(status) && status !== "confirmed") {
    add("Payment received", "paid", 0.4);
  }
  if (["dispatched", "delivered", "completed"].includes(status)) {
    add("Out for delivery / ready for pickup", "dispatched", 1);
  }
  if (["delivered", "completed"].includes(status)) {
    add("Delivered / collected", "delivered", 3);
  }
  if (status === "cancelled") {
    steps.push({
      at: new Date().toISOString(),
      label: "Order cancelled",
      status: "cancelled",
    });
  }
  return steps;
}

export const useOrdersStore = create<OrdersState>()(
  persist(
    (set, get) => ({
      orders: seedOrders.map((o) => ({
        ...o,
        discount: o.discount ?? 0,
        customerName: o.customerName ?? "Kirukib Abebe",
        customerPhone: o.customerPhone ?? "+251911000000",
        notes: o.notes ?? "",
        timeline: o.timeline ?? timelineFor(o.status, o.createdAt),
      })),
      addOrder: (payload) => {
        const createdAt = new Date().toISOString();
        const discount = payload.discount ?? 0;
        const status =
          payload.status ??
          (payload.paymentMethod === "pay_at_branch" ? "confirmed" : "paid");
        const order: Order = {
          ...payload,
          discount,
          id: `ord_${Date.now()}`,
          createdAt,
          status,
          riderAssigned: false,
          timeline: timelineFor(status, createdAt),
        };
        set({ orders: [order, ...get().orders] });
        return order;
      },
      updateStatus: (id, status) =>
        set({
          orders: get().orders.map((o) => {
            if (o.id !== id) return o;
            const next = {
              ...o,
              status,
              riderAssigned:
                status === "dispatched" || status === "delivered"
                  ? true
                  : o.riderAssigned,
            };
            const stamp = new Date().toISOString();
            const label =
              status === "dispatched"
                ? "Rider assigned / ready"
                : status === "delivered"
                  ? "Delivered / collected"
                  : status === "cancelled"
                    ? "Order cancelled"
                    : `Status: ${status}`;
            return {
              ...next,
              timeline: [...(o.timeline ?? []), { at: stamp, label, status }],
            };
          }),
        }),
      cancelOrder: (id) => get().updateStatus(id, "cancelled"),
      getById: (id) => get().orders.find((o) => o.id === id),
      getByPickupCode: (code) => {
        const normalized = code.trim().toUpperCase();
        if (!normalized) return undefined;
        return get().orders.find(
          (o) => (o.pickupCode ?? "").toUpperCase() === normalized
        );
      },
    }),
    {
      name: "gishen-orders",
      storage: createJSONStorage(() => AsyncStorage),
      version: 4,
      migrate: (persisted: unknown) => {
        const state = (persisted ?? {}) as Partial<OrdersState>;
        if (!state.orders?.length) {
          return {
            ...state,
            orders: seedOrders.map((o) => ({
              ...o,
              discount: o.discount ?? 0,
              customerName: o.customerName ?? "Kirukib Abebe",
              customerPhone: o.customerPhone ?? "+251911000000",
              timeline: timelineFor(o.status, o.createdAt),
            })),
          };
        }
        return {
          ...state,
          orders: state.orders.map((o) => ({
            ...o,
            discount: o.discount ?? 0,
            timeline: o.timeline ?? timelineFor(o.status, o.createdAt),
          })),
        };
      },
    }
  )
);