'use client';

import React, { createContext, useContext, useState, useEffect, useCallback } from 'react';
import { useRouter } from 'next/navigation';
import { API_URL } from './config';
import { withSessionRequest } from './csrf';

interface AuthUser {
  userId: number;
  username: string;
  role: string;
}

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

const AuthContext = createContext<AuthContextValue>({
  user: null,
  loading: true,
  login: async () => {},
  logout: () => {},
  isAuthenticated: false,
});

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

  const loadUser = useCallback(async () => {
    try {
      const res = await fetch(`${API_URL}/api/auth/me`, withSessionRequest());
      if (res.ok) {
        const data = await res.json();
        setUser({ userId: data.id, username: data.username, role: data.role });
      } else if (res.status === 401) {
        // access token expired → try refresh via cookie
        try {
          const rRes = await fetch(`${API_URL}/api/auth/refresh`, withSessionRequest({ method: 'POST' }, { csrf: true }));
          if (rRes.ok) {
            const d = await rRes.json();
            setUser({ userId: 0, username: d.username, role: d.role });
          }
        } catch { /* silent */ }
      }
    } catch {
      // silent
    } finally {
      setLoading(false);
    }
  }, []);

  useEffect(() => { loadUser(); }, [loadUser]);

  const login = async (username: string, password: string) => {
    const res = await fetch(`${API_URL}/api/auth/login`, withSessionRequest({
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ username, password }),
    }, { csrf: true }));

    if (!res.ok) {
      const d = await res.json();
      throw new Error(d.message ?? '로그인 실패');
    }

    const d = await res.json();
    // Tokens are set as HttpOnly cookies by the server
    setUser({ userId: 0, username: d.username, role: d.role });

    // Fetch actual userId from /me
    try {
      const meRes = await fetch(`${API_URL}/api/auth/me`, withSessionRequest());
      if (meRes.ok) {
        const me = await meRes.json();
        setUser({ userId: me.id, username: me.username, role: me.role });
      }
    } catch { /* fallback — already set basic info */ }
  };

  const logout = async () => {
    try {
      await fetch(`${API_URL}/api/auth/logout`, withSessionRequest({ method: 'POST' }, { csrf: true }));
    } catch { /* silent */ }
    setUser(null);
  };

  return (
    <AuthContext.Provider value={{ user, loading, login, logout, isAuthenticated: !!user }}>
      {children}
    </AuthContext.Provider>
  );
}

export function useAuth() {
  return useContext(AuthContext);
}