import { type ClassValue, clsx } from "clsx"
import { twMerge } from "tailwind-merge"

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs))
}

// Session management utilities
export interface User {
  id: number;
  nim?: string;
  username?: string;
  nip?: string;
  role: string;
}

export interface Session {
  isAuthenticated: boolean;
  user?: User;
  expiresAt?: string;
  issuedAt?: string;
}

// Check if user is authenticated
export async function checkAuth(): Promise<Session> {
  try {
    const response = await fetch('/api/auth/check', {
      method: 'GET',
      credentials: 'include',
    });

    if (response.ok) {
      const data = await response.json();
      return data;
    } else {
      return { isAuthenticated: false };
    }
  } catch (error) {
    console.error('Auth check error:', error);
    return { isAuthenticated: false };
  }
}

// Logout user
export async function logout(): Promise<boolean> {
  try {
    const response = await fetch('/api/auth/logout', {
      method: 'POST',
      credentials: 'include',
    });

    if (response.ok) {
      // Clear any client-side state
      localStorage.removeItem('sidebarCollapsed');
      return true;
    }
    return false;
  } catch (error) {
    console.error('Logout error:', error);
    return false;
  }
}

// Check if session is expired
export function isSessionExpired(expiresAt?: string): boolean {
  if (!expiresAt) return true;
  
  const expirationTime = new Date(expiresAt).getTime();
  const currentTime = Date.now();
  
  return currentTime >= expirationTime;
}

// Format date for display
export function formatDate(dateString: string): string {
  const date = new Date(dateString);
  return date.toLocaleDateString('id-ID', {
    year: 'numeric',
    month: 'long',
    day: 'numeric',
    hour: '2-digit',
    minute: '2-digit'
  });
}