import {
  createContext,
  useCallback,
  useContext,
  useEffect,
  useMemo,
  useState,
  type ReactNode,
} from "react";
import { setUnauthorizedHandler, tokenStore } from "@/api/client";
import { fetchMe, login as loginRequest, logoutRequest } from "@/api/services";
import type { AppUser } from "@/api/types";

interface AuthContextValue {
  user: AppUser | null;
  loading: boolean;
  login: (email: string, password: string) => Promise<void>;
  logout: () => void;
}

const AuthContext = createContext<AuthContextValue | undefined>(undefined);

export function AuthProvider({ children }: { children: ReactNode }) {
  const [user, setUser] = useState<AppUser | null>(null);
  const [loading, setLoading] = useState(true);

  const logout = useCallback(() => {
    const refresh = tokenStore.getRefresh();
    if (refresh) void logoutRequest(refresh).catch(() => undefined); // revoke server-side
    tokenStore.clear();
    setUser(null);
  }, []);

  useEffect(() => {
    setUnauthorizedHandler(() => setUser(null));
  }, []);

  // Restore session on load.
  useEffect(() => {
    const token = tokenStore.get();
    if (!token) {
      setLoading(false);
      return;
    }
    fetchMe()
      .then((u) => {
        if (u.role === "admin") setUser(u);
        else logout();
      })
      .catch(() => logout())
      .finally(() => setLoading(false));
  }, [logout]);

  const login = useCallback(async (email: string, password: string) => {
    const token = await loginRequest(email, password);
    tokenStore.set(token.access_token, token.refresh_token);
    const me = await fetchMe();
    setUser(me);
  }, []);

  const value = useMemo(
    () => ({ user, loading, login, logout }),
    [user, loading, login, logout],
  );

  return <AuthContext.Provider value={value}>{children}</AuthContext.Provider>;
}

// eslint-disable-next-line react-refresh/only-export-components
export function useAuth() {
  const ctx = useContext(AuthContext);
  if (!ctx) throw new Error("useAuth must be used within AuthProvider");
  return ctx;
}