frontend/src/components/Sidebar.js

import React from 'react';
import { motion, AnimatePresence } from 'framer-motion';
import { 
  PlusIcon, 
  XMarkIcon, 
  ChatBubbleLeftIcon,
  TrashIcon,
  HomeIcon
} from '@heroicons/react/24/outline';

const Sidebar = ({ 
  open, 
  onClose, 
  conversations, 
  activeConversationId, 
  onConversationSelect, 
  onNewChat, 
  onDeleteConversation,
  onBackToHome,
  darkMode 
}) => {
  const formatDate = (date) => {
    const now = new Date();
    const messageDate = new Date(date);
    const diffTime = Math.abs(now - messageDate);
    const diffDays = Math.ceil(diffTime / (1000 * 60 * 60 * 24));

    if (diffDays === 1) return 'Today';
    if (diffDays === 2) return 'Yesterday';
    if (diffDays <= 7) return `${diffDays} days ago`;
    return messageDate.toLocaleDateString();
  };

  const sidebarVariants = {
    open: {
      x: 0,
      transition: {
        type: "spring",
        stiffness: 300,
        damping: 30
      }
    },
    closed: {
      x: -280,
      transition: {
        type: "spring",
        stiffness: 300,
        damping: 30
      }
    }
  };

  const overlayVariants = {
    open: { opacity: 1 },
    closed: { opacity: 0 }
  };

  return (
    <>
      {/* Mobile Overlay */}
      <AnimatePresence>
        {open && (
          <motion.div
            variants={overlayVariants}
            initial="closed"
            animate="open"
            exit="closed"
            className="fixed inset-0 bg-black bg-opacity-50 z-40 md:hidden"
            onClick={onClose}
          />
        )}
      </AnimatePresence>

      {/* Sidebar */}
      <motion.aside
        variants={sidebarVariants}
        initial="closed"
        animate={open ? "open" : "closed"}
        className={`fixed left-0 top-16 h-[calc(100vh-4rem)] w-64 z-50 ${
          darkMode 
            ? 'bg-gray-900 border-gray-700' 
            : 'bg-white border-gray-200'
        } border-r shadow-lg flex flex-col`}
      >
        {/* Header */}
        <div className="p-4 border-b border-gray-200 dark:border-gray-700">
          <div className="flex items-center justify-between mb-4">
            <h2 className="font-semibold text-lg">Conversations</h2>
            <button
              onClick={onClose}
              className={`p-1 rounded-lg transition-colors md:hidden ${
                darkMode
                  ? 'hover:bg-gray-800 text-gray-400'
                  : 'hover:bg-gray-100 text-gray-500'
              }`}
            >
              <XMarkIcon className="w-5 h-5" />
            </button>
          </div>

          <div className="space-y-2">
            <motion.button
              whileHover={{ scale: 1.02 }}
              whileTap={{ scale: 0.98 }}
              onClick={onNewChat}
              className={`w-full flex items-center gap-3 px-3 py-2 rounded-lg transition-colors ${
                darkMode
                  ? 'bg-gray-800 hover:bg-gray-700 text-white border-gray-600'
                  : 'bg-gray-50 hover:bg-gray-100 text-gray-900 border-gray-300'
              } border`}
            >
              <PlusIcon className="w-4 h-4" />
              <span className="font-medium">New Chat</span>
            </motion.button>
            
            <motion.button
              whileHover={{ scale: 1.02 }}
              whileTap={{ scale: 0.98 }}
              onClick={onBackToHome}
              className={`w-full flex items-center gap-3 px-3 py-2 rounded-lg transition-colors ${
                darkMode
                  ? 'bg-primary-600 hover:bg-primary-700 text-white'
                  : 'bg-primary-50 hover:bg-primary-100 text-primary-900 border-primary-300'
              } border`}
            >
              <HomeIcon className="w-4 h-4" />
              <span className="font-medium">Back to Home</span>
            </motion.button>
          </div>
        </div>

        {/* Conversations List */}
        <div className="flex-1 overflow-y-auto p-2">
          {conversations.length === 0 ? (
            <div className={`text-center py-8 ${
              darkMode ? 'text-gray-500' : 'text-gray-400'
            }`}>
              <ChatBubbleLeftIcon className="w-12 h-12 mx-auto mb-3 opacity-50" />
              <p className="text-sm">No conversations yet</p>
              <p className="text-xs mt-1">Start a new chat to begin</p>
            </div>
          ) : (
            <div className="space-y-1">
              {conversations.map((conversation) => (
                <motion.button
                  key={conversation.id}
                  whileHover={{ x: 4 }}
                  onClick={() => {
                    onConversationSelect(conversation.id);
                    onClose();
                  }}
                  className={`w-full text-left p-3 rounded-lg transition-all group ${
                    activeConversationId === conversation.id
                      ? darkMode
                        ? 'bg-primary-600 text-white'
                        : 'bg-primary-50 text-primary-900 border-primary-200'
                      : darkMode
                        ? 'hover:bg-gray-800 text-gray-300'
                        : 'hover:bg-gray-50 text-gray-700'
                  }`}
                >
                  <div className="flex items-start justify-between">
                    <div className="flex-1 min-w-0">
                      <p className="font-medium truncate text-sm">
                        {conversation.title}
                      </p>
                      <p className={`text-xs mt-1 ${
                        activeConversationId === conversation.id
                          ? 'text-primary-200'
                          : darkMode
                            ? 'text-gray-500'
                            : 'text-gray-500'
                      }`}>
                        {formatDate(conversation.createdAt)}
                      </p>
                    </div>
                    
                    <button
                      onClick={(e) => {
                        e.stopPropagation();
                        if (window.confirm('Are you sure you want to delete this conversation?')) {
                          onDeleteConversation(conversation.id);
                        }
                      }}
                      className={`opacity-0 group-hover:opacity-100 p-1 rounded transition-opacity ${
                        darkMode
                          ? 'hover:bg-gray-700 text-gray-400'
                          : 'hover:bg-gray-200 text-gray-500'
                      }`}
                    >
                      <TrashIcon className="w-4 h-4" />
                    </button>
                  </div>
                </motion.button>
              ))}
            </div>
          )}
        </div>

        {/* Footer */}
        <div className={`p-4 border-t ${
          darkMode ? 'border-gray-700' : 'border-gray-200'
        }`}>
          <div className={`text-xs ${
            darkMode ? 'text-gray-500' : 'text-gray-400'
          }`}>
            <p>CA Study Assistant v2.0</p>
            <p className="mt-1">Powered by AI</p>
          </div>
        </div>
      </motion.aside>
    </>
  );
};

export default Sidebar;