import React, { useState, useEffect, useRef } from 'react';
import { Link, useLocation } from 'react-router-dom';
import { 
  HomeIcon, 
  AcademicCapIcon,
  BookOpenIcon,
  HandThumbUpIcon,
  WrenchScrewdriverIcon,
  UserIcon,
  ArrowRightOnRectangleIcon
} from '@heroicons/react/24/outline';
import HitokotoBar from './HitokotoBar';
import { api } from '../services/api';

interface User {
  name: string;
  email: string;
  role: string;
}

const Layout: React.FC<{ children: React.ReactNode }> = ({ children }) => {
  const location = useLocation();
  const [isTransitioning, setIsTransitioning] = useState(false);
  const previousPathRef = useRef(location.pathname);
  const userData = localStorage.getItem('user');
  const user: User | null = userData ? JSON.parse(userData) : null;
  const [unreadCount, setUnreadCount] = useState<number>(0);

  // Lightweight online presence: send heartbeat periodically
  useEffect(() => {
    let timer: any;
    const sendHeartbeat = async () => {
      try {
        if (!user?.email) return;
        const token = localStorage.getItem('token') || '';
        const base = (((api.defaults as any)?.baseURL as string) || '').replace(/\/$/, '');
        await fetch(`${base}/api/auth/online/heartbeat`, {
          method: 'POST',
          headers: {
            'Authorization': `Bearer ${token}`,
            'Content-Type': 'application/json',
            'user-role': user.role || 'visitor',
            'user-info': userData || ''
          },
          body: JSON.stringify({ email: user.email, path: location.pathname })
        });
      } catch {}
    };
    sendHeartbeat();
    timer = setInterval(sendHeartbeat, 60000);
    return () => { if (timer) clearInterval(timer); };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [user?.email]);

  // Send a heartbeat on route changes for fresher session tracking
  useEffect(() => {
    const run = async () => {
      try {
        if (!user?.email) return;
        const token = localStorage.getItem('token') || '';
        const base = (((api.defaults as any)?.baseURL as string) || '').replace(/\/$/, '');
        await fetch(`${base}/api/auth/online/heartbeat`, {
          method: 'POST',
          headers: {
            'Authorization': `Bearer ${token}`,
            'Content-Type': 'application/json',
            'user-role': user.role || 'visitor',
            'user-info': userData || ''
          },
          body: JSON.stringify({ email: user.email, path: location.pathname })
        });
      } catch {}
    };
    run();
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [location.pathname]);

  // Admin unread message badge (non-invasive)
  useEffect(() => {
    let timer: any;
    const run = async () => {
      try {
        if (user?.role !== 'admin') return;
        const token = localStorage.getItem('token') || '';
        const base = (((api.defaults as any)?.baseURL as string) || '').replace(/\/$/, '');
        const resp = await fetch(`${base}/api/messages/unread-count`, {
          headers: {
            'Authorization': `Bearer ${token}`,
            'user-role': 'admin',
            'user-info': userData || ''
          }
        });
        if (resp.ok) {
          const data = await resp.json();
          if (typeof data?.count === 'number') setUnreadCount(data.count);
        }
      } catch {}
    };
    run();
    if (user?.role === 'admin') {
      timer = setInterval(run, 60000);
    }
    return () => { if (timer) clearInterval(timer); };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [user?.role]);

  // Admin unread message badge (non-invasive)
  useEffect(() => {
    let timer: any;
    const run = async () => {
      try {
        if (user?.role !== 'admin') return;
        const token = localStorage.getItem('token') || '';
        const base = (((api.defaults as any)?.baseURL as string) || '').replace(/\/$/, '');
        const resp = await fetch(`${base}/api/messages/unread-count`, {
          headers: {
            'Authorization': `Bearer ${token}`,
            'user-role': 'admin',
            'user-info': userData || ''
          }
        });
        if (resp.ok) {
          const data = await resp.json();
          if (typeof data?.count === 'number') setUnreadCount(data.count);
        }
      } catch {}
    };
    run();
    if (user?.role === 'admin') {
      timer = setInterval(run, 60000);
    }
    return () => { if (timer) clearInterval(timer); };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [user?.role]);

  const handleLogout = () => {
    localStorage.removeItem('token');
    localStorage.removeItem('user');
    window.location.href = '/';
  };

  let navigation = [
    { name: 'Home', href: '/dashboard', icon: HomeIcon },
    { name: 'Tutorial Tasks', href: '/tutorial-tasks', icon: AcademicCapIcon },
    { name: 'Weekly Practice', href: '/weekly-practice', icon: BookOpenIcon },
    { name: 'Votes', href: '/votes', icon: HandThumbUpIcon },
    { name: 'Toolkit', href: '/toolkit', icon: WrenchScrewdriverIcon },
    { name: 'Slides', href: '/slides', icon: BookOpenIcon },
    { name: 'Feedback', href: '/feedback', icon: UserIcon },
  ];

  // Hide Slides for visitors
  if (!user || user.role === 'visitor') {
    navigation = navigation.filter(item => item.name !== 'Slides');
  }

  // Add Manage link for admin users
  if (user?.role === 'admin') {
    navigation.push({ name: 'Manage', href: '/manage', icon: UserIcon });
  }

  return (
    <div className="min-h-screen bg-gray-50">
      {/* Navigation */}
      <nav className="bg-white shadow-sm border-b border-gray-200">
        <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8">
          <div className="flex justify-between h-16">
            <div className="flex">
              <div className="flex-shrink-0 flex items-center">
                <Link to="/dashboard" className="text-xl font-bold text-indigo-600">
                  Transcreation
                </Link>
              </div>
              <div className="hidden sm:ml-6 sm:flex sm:space-x-8">
                {navigation.map((item) => {
                  const isActive = location.pathname === item.href;
                  return (
                    <Link
                      key={item.name}
                      to={item.href}
                      className={`inline-flex items-center px-1 pt-1 border-b-2 text-sm font-medium transition-all duration-200 ease-in-out ${
                        isActive
                          ? 'border-indigo-500 text-gray-900'
                          : 'border-transparent text-gray-500 hover:border-gray-300 hover:text-gray-700'
                      }`}
                    >
                      <item.icon className="h-4 w-4 mr-1" />
                      {item.name}
                      {item.name === 'Feedback' && user?.role === 'admin' && unreadCount > 0 && (
                        <span className="ml-2 inline-flex items-center justify-center min-w-[16px] h-4 px-1 rounded-full bg-red-600 text-white text-[10px] leading-none">{unreadCount > 99 ? '99+' : unreadCount}</span>
                      )}
                    </Link>
                  );
                })}
              </div>
            </div>
            <div className="flex items-center">
              {user && (
                <div className="flex items-center">
                  <button
                    onClick={handleLogout}
                    className="text-gray-500 hover:text-gray-700 flex items-center"
                  >
                    <ArrowRightOnRectangleIcon className="h-4 w-4 mr-1" />
                    Logout
                  </button>
                </div>
              )}
            </div>
          </div>
        </div>
      </nav>

      {/* Mobile Navigation */}
      <div className="sm:hidden">
        <div className="pt-2 pb-3 space-y-1">
          {navigation.map((item) => {
            const isActive = location.pathname === item.href;
            return (
              <Link
                key={item.name}
                to={item.href}
                className={`block pl-3 pr-4 py-2 border-l-4 text-base font-medium transition-all duration-200 ease-in-out ${
                  isActive
                    ? 'bg-indigo-50 border-indigo-500 text-indigo-700'
                    : 'border-transparent text-gray-600 hover:bg-gray-50 hover:border-gray-300 hover:text-gray-800'
                }`}
              >
                <div className="flex items-center">
                  <item.icon className="h-4 w-4 mr-2" />
                  {item.name}
                </div>
              </Link>
            );
          })}
        </div>
      </div>

                        {/* Main Content */}
                  <main>
                    {!isTransitioning && children}
                  </main>
      
      {/* Transition Loading Indicator */}
      {isTransitioning && (
        <div className="fixed top-1/2 left-1/2 transform -translate-x-1/2 -translate-y-1/2 z-50">
          <div className="bg-white rounded-lg shadow-lg p-4 flex items-center space-x-3">
            <div className="animate-spin rounded-full h-6 w-6 border-b-2 border-indigo-600"></div>
            <span className="text-gray-700 font-medium">Loading...</span>
          </div>
        </div>
      )}
      <HitokotoBar />
    </div>
  );
};

export default Layout;