import React, { useState, useEffect } from 'react';
import axios from 'axios';
import { motion } from 'framer-motion';
import { useNavigate, useLocation } from 'react-router-dom';
import { useAuth } from '../context/AuthContext';
import { useTranslation } from 'react-i18next';
import { 
  LayoutDashboard, 
  PenTool, 
  Calendar, 
  Trophy, 
  Settings, 
  LogOut,
  User
} from 'lucide-react';

const SidebarItem = ({ icon: Icon, label, active, onClick, badge }) => (
  <motion.button
    whileHover={{ x: 5 }}
    whileTap={{ scale: 0.95 }}
    onClick={onClick}
    className={`w-full flex items-center justify-between px-6 py-4 rounded-xl transition-all group ${
      active 
      ? 'bg-primary text-on-primary rough-border shadow-[4px_4px_0px_0px_rgba(0,0,0,0.1)]' 
      : 'text-on-surface-variant hover:bg-surface-variant hover:text-primary'
    }`}
  >
    <div className="flex items-center gap-4">
      <Icon size={24} className={active ? 'text-secondary' : 'group-hover:text-primary'} />
      <span className="text-xl font-bold font-display-lg tracking-wide">{label}</span>
    </div>
    {badge && (
      <span className={`px-2 py-1 rounded-full text-xs font-bold ${active ? 'bg-secondary text-primary' : 'bg-primary/10 text-primary'}`}>
        {badge}
      </span>
    )}
  </motion.button>
);

let cachedProjectCount = null;

const Sidebar = () => {
  const navigate = useNavigate();
  const location = useLocation();
  const { logout, user } = useAuth();
  const { t } = useTranslation();
  const [projectCount, setProjectCount] = useState(() => {
    if (cachedProjectCount !== null) return cachedProjectCount;
    const stored = localStorage.getItem('tf_project_count');
    return stored ? parseInt(stored, 10) : 0;
  });

  useEffect(() => {
    if (!user) return;
    const fetchProjectCount = async () => {
      try {
        const API_URL = import.meta.env.VITE_API_URL;
        const res = await axios.get(`${API_URL}/graphs/user/${user.id}`);
        if (Array.isArray(res.data)) {
          const count = res.data.length;
          setProjectCount(count);
          cachedProjectCount = count;
          localStorage.setItem('tf_project_count', count.toString());
        }
      } catch (err) {
        console.error('[Sidebar] Failed to fetch project count:', err);
      }
    };

    fetchProjectCount();
    const interval = setInterval(fetchProjectCount, 10000);
    return () => clearInterval(interval);
  }, [user]);

  const handleLogout = () => {
    logout();
    navigate('/auth');
  };

  const menuItems = [
    { icon: LayoutDashboard, labelKey: 'projects', path: '/dashboard' },
    { icon: PenTool, labelKey: 'canvas', path: '/canvas' },
    { icon: Calendar, labelKey: 'habits', path: '/habits' },
    { icon: User, labelKey: 'profile', path: '/profile' },
    { icon: Settings, labelKey: 'settings', path: '/settings' },
  ];

  return (
    <aside className="w-80 border-r-4 border-primary bg-surface-container-lowest p-6 flex flex-col gap-10 h-screen sticky top-0">
      <div className="flex items-center gap-3 px-4 cursor-pointer" onClick={() => navigate('/')}>
        <div className="w-12 h-12 bg-primary rounded-xl flex items-center justify-center text-on-primary">
          <LayoutDashboard size={28} />
        </div>
        <span className="text-3xl font-display-lg text-primary">TaskFlow</span>
      </div>

      <nav className="flex flex-col gap-2 flex-grow">
        <div className="px-4 mb-2 text-xs font-bold uppercase tracking-[0.2em] text-on-surface-variant/50">
          {t('sidebar.main_menu', 'Main Menu')}
        </div>
        {menuItems.map((item) => (
          <SidebarItem
            key={item.labelKey}
            icon={item.icon}
            label={t(`sidebar.${item.labelKey}`)}
            active={location.pathname === item.path}
            onClick={() => navigate(item.path)}
            badge={item.labelKey === 'projects' ? projectCount.toString() : null}
          />
        ))}
      </nav>

      <div className="flex flex-col gap-4">
        <div className="p-4 bg-secondary/5 rough-border border-dashed border-secondary/30 flex flex-col gap-4">
          <div className="flex flex-col gap-1">
            <div className="flex items-center justify-between">
              <span className="font-accent-note text-2xl text-secondary">
                {user?.subscriptionTier === 'Ultra' ? 'Ultra' : user?.subscriptionTier === 'Pro' ? 'Pro' : t('sidebar.free_plan')}
              </span>
              {(!user?.subscriptionTier || user?.subscriptionTier === 'Free') && (
                <span className="text-xs font-bold text-primary">{projectCount}/3 Slots</span>
              )}
            </div>
            <p className="text-[10px] text-on-surface-variant/70 font-semibold tracking-wide uppercase mt-1">
              {user?.subscriptionTier === 'Ultra' 
                ? t('sidebar.ultra_active', 'All Limits Unlocked') 
                : user?.subscriptionTier === 'Pro' 
                  ? t('sidebar.pro_active', 'AI: {{count}}/200 daily', { count: user?.dailyAiGenerationsCount || 0 }) 
                  : t('sidebar.free_active', 'AI: {{count}}/3 daily', { count: user?.dailyAiGenerationsCount || 0 })}
            </p>
          </div>
          {user?.subscriptionTier !== 'Ultra' && (
            <button 
              onClick={() => navigate('/subscription')}
              className="w-full py-2 bg-primary text-on-primary text-sm font-bold rounded-lg hover:bg-secondary hover:text-primary transition-all cursor-pointer"
            >
              {user?.subscriptionTier === 'Pro' ? t('sidebar.go_ultra', 'Go Ultra') : t('sidebar.upgrade_now')}
            </button>
          )}
        </div>

        <button 
          onClick={handleLogout}
          className="w-full flex items-center gap-4 px-6 py-4 text-on-surface-variant hover:text-error transition-colors font-bold cursor-pointer"
        >
          <LogOut size={24} />
          <span className="font-display-lg text-xl">{t('sidebar.logout')}</span>
        </button>
      </div>
    </aside>
  );
};

export default Sidebar;