"use client";
/**
 * UserContext：基于 XState actor context 和 selector 的 React Provider。
 */
import type { Dispatch, ReactNode } from "react";
import { createActorContext, shallowEqual } from "@xstate/react";
import type { SnapshotFrom } from "xstate";

import { userMachine } from "./user-machine";
import type { UserState as MachineContext, UserEvent } from "./user-machine";

/**
 * 对外暴露的 State 形状（保持与原 UserState 兼容）
 */
interface UserState {
  currentUser: MachineContext["currentUser"];
  isLoading: boolean;
  avatarUrl: string | null;
  isVip: boolean;
  creditBalance: number;
  entitlements: MachineContext["entitlements"];
}

type UserSnapshot = SnapshotFrom<typeof userMachine>;
type UserSelector<T> = (snapshot: UserSnapshot) => T;

const UserActorContext = createActorContext(userMachine);

export interface UserProviderProps {
  children: ReactNode;
}

export function UserProvider({ children }: UserProviderProps) {
  return <UserActorContext.Provider>{children}</UserActorContext.Provider>;
}

export function useUserState(): UserState {
  return useUserSelector(selectUserState, shallowEqual);
}

export function useUserDispatch(): Dispatch<UserEvent> {
  return UserActorContext.useActorRef().send;
}

export function useUserSelector<T>(
  selector: UserSelector<T>,
  compare?: (previous: T, next: T) => boolean,
): T {
  return UserActorContext.useSelector(selector, compare);
}

function selectUserState(state: UserSnapshot): UserState {
  return {
    currentUser: state.context.currentUser,
    isLoading:
      state.matches("initializing") ||
      state.matches("fetching") ||
      state.matches("loggingOut") ||
      state.context.isLoading,
    avatarUrl: state.context.avatarUrl,
    isVip: state.context.isVip,
    creditBalance: state.context.creditBalance,
    entitlements: state.context.entitlements,
  };
}