import {
  createContext,
  useContext,
  useEffect,
  useState,
  ReactNode,
} from "react";
import type { IUser } from "@/types";
import { auth as authAPI } from "@/api";

interface AuthContextType {
  user: IUser | null;
  isAuthenticated: boolean;
  isLoading: boolean;
  error: string | null;
  login: (username: string, password: string) => Promise<void>;
  logout: () => Promise<void>;
}

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

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

  // Initialize auth state on mount
  useEffect(() => {
    async function initAuth() {
      try {
        const currentUser = await authAPI.getCurrentUser();
        setUser(currentUser);
        setError(null);
      } catch (err) {
        setUser(null);
        // Not an error if not authenticated — just not logged in
      } finally {
        setIsLoading(false);
      }
    }

    initAuth();

    // Listen for logout events from other tabs/contexts
    const handleLogout = () => {
      setUser(null);
    };

    window.addEventListener("auth:logout", handleLogout);
    return () => window.removeEventListener("auth:logout", handleLogout);
  }, []);

  const login = async (username: string, password: string) => {
    try {
      setIsLoading(true);
      setError(null);
      await authAPI.login(username, password);
      const currentUser = await authAPI.getCurrentUser();
      setUser(currentUser);
    } catch (err) {
      const message =
        err instanceof Error ? err.message : "Login failed";
      setError(message);
      throw err;
    } finally {
      setIsLoading(false);
    }
  };

  const logout = async () => {
    try {
      await authAPI.logout();
      setUser(null);
      setError(null);
    } catch (err) {
      console.error("Logout error:", err);
      // Clear local state even if logout fails
      setUser(null);
    }
  };

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

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