"use client";

import { createContext, useContext, useState, useEffect, ReactNode } from "react";

interface User {
  id: number;
  email: string;
}

interface AuthContextType {
  user: User | null;
  token: string | null;
  isLoading: boolean;
  login: (email: string, password: string) => Promise<void>;
  register: (email: string, password: string) => Promise<void>;
  logout: () => void;
}

const AuthContext = createContext<AuthContextType | null>(null);

export function AuthProvider({ children }: { children: ReactNode }) {
  const [user, setUser] = useState<User | null>(null);
  const [token, setToken] = useState<string | null>(null);
  const [isLoading, setIsLoading] = useState(true);

  useEffect(() => {
    const storedToken = localStorage.getItem("token");
    if (storedToken) {
      setToken(storedToken);
      fetchUser(storedToken);
    } else {
      setIsLoading(false);
    }
  }, []);

  const fetchUser = async (authToken: string) => {
    try {
      const res = await fetch("http://localhost:8000/api/auth/me", {
        headers: { Authorization: `Bearer ${authToken}` },
      });
      if (res.ok) {
        const userData = await res.json();
        setUser(userData);
      } else {
        localStorage.removeItem("token");
        setToken(null);
      }
    } catch {
      localStorage.removeItem("token");
      setToken(null);
    } finally {
      setIsLoading(false);
    }
  };

  const login = async (email: string, password: string) => {
    const res = await fetch("http://localhost:8000/api/auth/login", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ email, password }),
    });

    if (!res.ok) {
      const error = await res.json();
      throw new Error(error.detail || "Login failed");
    }

    const data = await res.json();
    localStorage.setItem("token", data.access_token);
    setToken(data.access_token);
    setUser(data.user);
  };

  const register = async (email: string, password: string) => {
    const res = await fetch("http://localhost:8000/api/auth/register", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ email, password }),
    });

    if (!res.ok) {
      const error = await res.json();
      throw new Error(error.detail || "Registration failed");
    }

    const data = await res.json();
    localStorage.setItem("token", data.access_token);
    setToken(data.access_token);
    setUser(data.user);
  };

  const logout = () => {
    localStorage.removeItem("token");
    setToken(null);
    setUser(null);
  };

  return (
    <AuthContext.Provider value={{ user, token, isLoading, login, register, logout }}>
      {children}
    </AuthContext.Provider>
  );
}

export function useAuth() {
  const context = useContext(AuthContext);
  if (!context) {
    throw new Error("useAuth must be used within an AuthProvider");
  }
  return context;
}