'use client';

import { useState, useRef, useEffect } from 'react';
import {
  Box,
  TextField,
  IconButton,
  Paper,
  Typography,
  Avatar,
  CircularProgress,
  Chip,
  Drawer,
  List,
  ListItem,
  ListItemButton,
  ListItemText,
  ListItemIcon,
  Divider,
  Button,
  Dialog,
  DialogTitle,
  DialogContent,
  DialogActions,
  useMediaQuery,
  useTheme,
  Collapse,
  Menu,
  MenuItem,
  InputAdornment,
} from '@mui/material';
import {
  Send,
  SmartToy,
  Person,
  AutoAwesome,
  Chat,
  Delete,
  Add,
  Menu as MenuIcon,
  Close,
  ExpandMore,
  ExpandLess,
  Folder,
  FolderOpen,
  MoreVert,
  DriveFileMove,
  CreateNewFolder,
} from '@mui/icons-material';
import { motion, AnimatePresence } from 'framer-motion';
import { useAuth } from '@/lib/auth/AuthContext';
import apiClient from '@/lib/api/client';
import ReactMarkdown from 'react-markdown';
import remarkGfm from 'remark-gfm';
import { useTranslation } from '@/hooks/useTranslation';
import { useStreamingChat } from '@/hooks/useStreamingChat';
import { MessageFeedback } from './MessageFeedback';

interface Message {
  id: string;
  role: 'user' | 'assistant';
  content: string;
  timestamp: Date;
}

interface Conversation {
  id: string;
  title: string;
  messages: Array<{
    role: string;
    content: string;
    timestamp: string;
  }>;
  totalTokens: number;
  createdAt: string;
  updatedAt: string;
  metadata?: {
    groupName?: string | null;
    [key: string]: any;
  };
}

interface ConversationGroup {
  name: string;
  conversations: Conversation[];
  isCollapsed: boolean;
}


export const AIChatInterface: React.FC = () => {
  const { t } = useTranslation('ai');
  const [messages, setMessages] = useState<Message[]>([]);
  const [input, setInput] = useState('');
  const [isLoading, setIsLoading] = useState(false);
  const [streamingMessage, setStreamingMessage] = useState('');
  const [useStreaming, setUseStreaming] = useState(false); // Disable streaming for now - using non-streaming endpoint
  const [currentThinkingMessages, setCurrentThinkingMessages] = useState<string[]>([]);
  const [currentThinkingIndex, setCurrentThinkingIndex] = useState(0);
  const [conversations, setConversations] = useState<Conversation[]>([]);
  const [currentConversationId, setCurrentConversationId] = useState<string | null>(null);
  const [drawerOpen, setDrawerOpen] = useState(false);
  const [deleteDialogOpen, setDeleteDialogOpen] = useState(false);
  const [conversationToDelete, setConversationToDelete] = useState<string | null>(null);
  const [collapsedGroups, setCollapsedGroups] = useState<Set<string>>(new Set());
  const [contextMenu, setContextMenu] = useState<{ mouseX: number; mouseY: number; conversationId: string } | null>(null);
  const [moveToGroupDialog, setMoveToGroupDialog] = useState<{ open: boolean; conversationId: string | null }>({ open: false, conversationId: null });
  const [newGroupDialog, setNewGroupDialog] = useState(false);
  const [newGroupName, setNewGroupName] = useState('');
  const messagesEndRef = useRef<HTMLDivElement>(null);
  const thinkingIntervalRef = useRef<NodeJS.Timeout | null>(null);
  const { user } = useAuth();
  const { streamMessage, isStreaming } = useStreamingChat();
  const theme = useTheme();
  const isMobile = useMediaQuery(theme.breakpoints.down('md'));

  // Localized arrays that depend on translations
  const suggestedQuestions = [
    t('interface.suggestedQuestion1'),
    t('interface.suggestedQuestion2'),
    t('interface.suggestedQuestion3'),
    t('interface.suggestedQuestion4'),
  ];

  const thinkingMessages = [
    t('interface.thinking1'),
    t('interface.thinking2'),
    t('interface.thinking3'),
    t('interface.thinking4'),
    t('interface.thinking5'),
    t('interface.thinking6'),
    t('interface.thinking7'),
    t('interface.thinking8'),
    t('interface.thinking9'),
    t('interface.thinking10'),
    t('interface.thinking11'),
    t('interface.thinking12'),
    t('interface.thinking13'),
    t('interface.thinking14'),
    t('interface.thinking15'),
    t('interface.thinking16'),
    t('interface.thinking17'),
    t('interface.thinking18'),
    t('interface.thinking19'),
  ];

  // Get a random selection of 3-5 thinking messages
  const getRandomThinkingMessages = () => {
    const count = Math.floor(Math.random() * 3) + 3; // 3 to 5
    const shuffled = [...thinkingMessages].sort(() => Math.random() - 0.5);
    return shuffled.slice(0, count);
  };

  const scrollToBottom = () => {
    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' });
  };

  useEffect(() => {
    scrollToBottom();
  }, [messages, streamingMessage]);

  // Load conversations on mount
  useEffect(() => {
    loadConversations();
  }, []);

  // Cycle through thinking messages while loading
  useEffect(() => {
    if (isLoading) {
      const randomMessages = getRandomThinkingMessages();
      setCurrentThinkingMessages(randomMessages);
      setCurrentThinkingIndex(0);

      thinkingIntervalRef.current = setInterval(() => {
        setCurrentThinkingIndex((prev) => (prev + 1) % randomMessages.length);
      }, 2000); // Change message every 2 seconds
    } else {
      if (thinkingIntervalRef.current) {
        clearInterval(thinkingIntervalRef.current);
        thinkingIntervalRef.current = null;
      }
      setCurrentThinkingMessages([]);
      setCurrentThinkingIndex(0);
    }

    return () => {
      if (thinkingIntervalRef.current) {
        clearInterval(thinkingIntervalRef.current);
      }
    };
  }, [isLoading]);

  const loadConversations = async () => {
    try {
      const response = await apiClient.get('/api/v1/ai/conversations');
      setConversations(response.data.data.conversations);
    } catch (error) {
      console.error('Failed to load conversations:', error);
    }
  };

  const loadConversation = async (conversationId: string) => {
    try {
      const response = await apiClient.get(`/api/v1/ai/conversations/${conversationId}`);
      const conversation = response.data.data.conversation;

      // Convert conversation messages to Message format
      const loadedMessages: Message[] = conversation.messages.map((msg: any, index: number) => ({
        id: `${conversationId}-${index}`,
        role: msg.role === 'user' ? 'user' : 'assistant',
        content: msg.content,
        timestamp: new Date(msg.timestamp),
      }));

      setMessages(loadedMessages);
      setCurrentConversationId(conversationId);
      if (isMobile) {
        setDrawerOpen(false);
      }
    } catch (error) {
      console.error('Failed to load conversation:', error);
    }
  };

  const handleNewConversation = () => {
    setMessages([]);
    setCurrentConversationId(null);
    if (isMobile) {
      setDrawerOpen(false);
    }
  };

  const handleDeleteConversation = async () => {
    if (!conversationToDelete) return;

    try {
      await apiClient.delete(`/api/v1/ai/conversations/${conversationToDelete}`);

      // If deleting current conversation, start new one
      if (conversationToDelete === currentConversationId) {
        handleNewConversation();
      }

      // Reload conversations list
      await loadConversations();
      setDeleteDialogOpen(false);
      setConversationToDelete(null);
    } catch (error) {
      console.error('Failed to delete conversation:', error);
    }
  };

  // Group conversations by their group name
  const organizeConversations = (): ConversationGroup[] => {
    const groups: { [key: string]: Conversation[] } = {};
    const ungroupedLabel = t('interface.ungrouped');

    // Separate conversations by group
    conversations.forEach((conv) => {
      const groupName = conv.metadata?.groupName || ungroupedLabel;
      if (!groups[groupName]) {
        groups[groupName] = [];
      }
      groups[groupName].push(conv);
    });

    // Convert to array and sort
    const groupArray: ConversationGroup[] = Object.entries(groups)
      .map(([name, convs]) => ({
        name,
        conversations: convs.sort((a, b) => new Date(b.updatedAt).getTime() - new Date(a.updatedAt).getTime()),
        isCollapsed: collapsedGroups.has(name),
      }))
      .sort((a, b) => {
        // Ungrouped always last
        if (a.name === ungroupedLabel) return 1;
        if (b.name === ungroupedLabel) return -1;
        return a.name.localeCompare(b.name);
      });

    return groupArray;
  };

  const toggleGroupCollapse = (groupName: string) => {
    setCollapsedGroups((prev) => {
      const newSet = new Set(prev);
      if (newSet.has(groupName)) {
        newSet.delete(groupName);
      } else {
        newSet.add(groupName);
      }
      return newSet;
    });
  };

  const handleMoveToGroup = async (conversationId: string, groupName: string | null) => {
    try {
      await apiClient.patch(`/api/v1/ai/conversations/${conversationId}/group`, {
        groupName: groupName,
      });
      await loadConversations();
      setMoveToGroupDialog({ open: false, conversationId: null });
      setContextMenu(null);
    } catch (error) {
      console.error('Failed to move conversation to group:', error);
    }
  };

  const handleCreateNewGroup = async () => {
    if (!newGroupName.trim()) return;

    const conversationId = moveToGroupDialog.conversationId;
    if (conversationId) {
      await handleMoveToGroup(conversationId, newGroupName.trim());
    }
    setNewGroupName('');
    setNewGroupDialog(false);
  };

  const handleContextMenu = (event: React.MouseEvent, conversationId: string) => {
    event.preventDefault();
    setContextMenu({
      mouseX: event.clientX - 2,
      mouseY: event.clientY - 4,
      conversationId,
    });
  };

  const handleCloseContextMenu = () => {
    setContextMenu(null);
  };

  const getExistingGroups = (): string[] => {
    const groups = new Set<string>();
    conversations.forEach((conv) => {
      if (conv.metadata?.groupName) {
        groups.add(conv.metadata.groupName);
      }
    });
    return Array.from(groups).sort();
  };

  const handleSend = async (message?: string) => {
    const messageText = message || input.trim();
    if (!messageText || isLoading || isStreaming) return;

    const userMessage: Message = {
      id: Date.now().toString(),
      role: 'user',
      content: messageText,
      timestamp: new Date(),
    };

    setMessages((prev) => [...prev, userMessage]);
    setInput('');

    // Use streaming if enabled
    if (useStreaming) {
      setIsLoading(true);
      setStreamingMessage('');

      try {
        let accumulatedMessage = '';

        await streamMessage(
          {
            message: messageText,
            conversationId: currentConversationId || undefined,
          },
          (chunk) => {
            if (chunk.type === 'token' && chunk.content) {
              accumulatedMessage += chunk.content;
              setStreamingMessage(accumulatedMessage);
            }
          },
          // On complete
          () => {
            // Add the complete message to messages
            const assistantMessage: Message = {
              id: (Date.now() + 1).toString(),
              role: 'assistant',
              content: accumulatedMessage,
              timestamp: new Date(),
            };
            setMessages((prev) => [...prev, assistantMessage]);
            setStreamingMessage('');
            setIsLoading(false);

            // Reload conversations
            loadConversations();
          },
          // On error
          (error) => {
            console.error('Streaming error:', error);
            const errorMessage: Message = {
              id: (Date.now() + 1).toString(),
              role: 'assistant',
              content: t('interface.errorMessage'),
              timestamp: new Date(),
            };
            setMessages((prev) => [...prev, errorMessage]);
            setStreamingMessage('');
            setIsLoading(false);
          }
        );
      } catch (error) {
        console.error('Streaming failed:', error);
        setStreamingMessage('');
        setIsLoading(false);
      }
    } else {
      // Non-streaming fallback
      setIsLoading(true);

      try {
        const response = await apiClient.post('/api/v1/ai/chat', {
          message: messageText,
          conversationId: currentConversationId,
        });

        const responseData = response.data.data;
        const assistantMessage: Message = {
          id: (Date.now() + 1).toString(),
          role: 'assistant',
          content: responseData.message,
          timestamp: new Date(responseData.timestamp),
        };

        setMessages((prev) => [...prev, assistantMessage]);

        // Update current conversation ID if it's a new conversation
        if (!currentConversationId && responseData.conversationId) {
          setCurrentConversationId(responseData.conversationId);
        }

        // Reload conversations to update the list
        await loadConversations();
      } catch (error) {
        console.error('AI chat error:', error);
        const errorMessage: Message = {
          id: (Date.now() + 1).toString(),
          role: 'assistant',
          content: t('interface.errorMessage'),
          timestamp: new Date(),
        };
        setMessages((prev) => [...prev, errorMessage]);
      } finally {
        setIsLoading(false);
      }
    }
  };

  const handleSuggestedQuestion = (question: string) => {
    handleSend(question);
  };

  const drawerContent = (
    <Box sx={{ width: { xs: 280, md: 320 }, height: '100%', display: 'flex', flexDirection: 'column' }}>
      <Box sx={{ p: 2, borderBottom: 1, borderColor: 'divider' }}>
        <Box sx={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', mb: 2 }}>
          <Typography variant="h6" fontWeight="600">
            {t('history.title')}
          </Typography>
          {isMobile && (
            <IconButton onClick={() => setDrawerOpen(false)} size="small" aria-label={t('interface.closeDrawer')}>
              <Close />
            </IconButton>
          )}
        </Box>
        <Button
          fullWidth
          variant="contained"
          startIcon={<Add />}
          onClick={handleNewConversation}
          sx={{
            borderRadius: 2,
            textTransform: 'none',
            bgcolor: 'primary.light',
            color: 'primary.main',
            '&:hover': { bgcolor: 'primary.main', color: 'white' }
          }}
        >
          {t('chat.newChat')}
        </Button>
      </Box>
      <List sx={{ flex: 1, overflow: 'auto', py: 1 }}>
        {conversations.length === 0 ? (
          <Box sx={{ p: 3, textAlign: 'center' }}>
            <Chat sx={{ fontSize: 48, color: 'text.secondary', opacity: 0.3, mb: 1 }} />
            <Typography variant="body2" color="text.secondary">
              {t('history.noHistory')}
            </Typography>
          </Box>
        ) : (
          organizeConversations().map((group) => (
            <Box key={group.name}>
              {/* Group Header */}
              <ListItemButton
                onClick={() => toggleGroupCollapse(group.name)}
                sx={{
                  py: 1,
                  px: 2,
                  bgcolor: 'background.default',
                  '&:hover': { bgcolor: 'action.hover' },
                }}
              >
                <ListItemIcon sx={{ minWidth: 36 }}>
                  {group.isCollapsed ? <Folder /> : <FolderOpen />}
                </ListItemIcon>
                <ListItemText
                  primary={group.name}
                  secondary={t('interface.chatCount', { count: group.conversations.length })}
                  primaryTypographyProps={{
                    variant: 'body2',
                    fontWeight: 600,
                  }}
                  secondaryTypographyProps={{
                    variant: 'caption',
                  }}
                />
                {group.isCollapsed ? <ExpandMore fontSize="small" /> : <ExpandLess fontSize="small" />}
              </ListItemButton>

              {/* Conversations in Group */}
              <Collapse in={!group.isCollapsed} timeout="auto" unmountOnExit>
                <List disablePadding>
                  {group.conversations.map((conversation) => (
                    <ListItem key={conversation.id} disablePadding>
                      <ListItemButton
                        selected={conversation.id === currentConversationId}
                        onClick={() => loadConversation(conversation.id)}
                        onContextMenu={(e) => handleContextMenu(e, conversation.id)}
                        sx={{
                          mx: 1,
                          pl: 5,
                          borderRadius: 2,
                          mb: 0.5,
                          '&.Mui-selected': {
                            bgcolor: 'primary.light',
                            '&:hover': {
                              bgcolor: 'primary.light',
                            },
                          },
                        }}
                      >
                        <ListItemIcon sx={{ minWidth: 36 }}>
                          <Chat fontSize="small" />
                        </ListItemIcon>
                        <ListItemText
                          primary={conversation.title}
                          secondary={new Date(conversation.updatedAt).toLocaleDateString()}
                          primaryTypographyProps={{
                            noWrap: true,
                            fontSize: '0.875rem',
                            fontWeight: conversation.id === currentConversationId ? 600 : 400,
                          }}
                          secondaryTypographyProps={{
                            variant: 'caption',
                          }}
                        />
                        <IconButton
                          size="small"
                          onClick={(e) => {
                            e.stopPropagation();
                            if (isMobile) {
                              handleContextMenu(e, conversation.id);
                            } else {
                              setConversationToDelete(conversation.id);
                              setDeleteDialogOpen(true);
                            }
                          }}
                          sx={{ ml: 1 }}
                          aria-label={isMobile ? t('interface.moreOptions') : t('interface.deleteConversation')}
                        >
                          {isMobile ? <MoreVert fontSize="small" /> : <Delete fontSize="small" />}
                        </IconButton>
                      </ListItemButton>
                    </ListItem>
                  ))}
                </List>
              </Collapse>
            </Box>
          ))
        )}
      </List>
    </Box>
  );

  return (
    <Box sx={{ display: 'flex', height: 'calc(100vh - 200px)', gap: 2 }}>
      {/* Conversation History Sidebar - Desktop */}
      {!isMobile && (
        <Paper elevation={0} sx={{ width: 320, borderRadius: 2, overflow: 'hidden' }}>
          {drawerContent}
        </Paper>
      )}

      {/* Mobile Drawer */}
      <Drawer
        anchor="left"
        open={drawerOpen}
        onClose={() => setDrawerOpen(false)}
        ModalProps={{
          keepMounted: true, // Better mobile performance
        }}
      >
        {drawerContent}
      </Drawer>

      {/* Chat Area */}
      <Box
        sx={{
          flex: 1,
          display: 'flex',
          flexDirection: 'column',
          background: 'linear-gradient(135deg, #FFF5F5 0%, #FFE4E1 100%)',
          borderRadius: 2,
          overflow: 'hidden',
        }}
      >
        {/* Header */}
        <Paper
          elevation={0}
          sx={{
            p: 2,
            borderRadius: 0,
            background: 'rgba(255, 255, 255, 0.95)',
            backdropFilter: 'blur(10px)',
            borderBottom: '1px solid',
            borderColor: 'divider',
          }}
        >
          <Box sx={{ display: 'flex', alignItems: 'center', gap: 2 }}>
            {isMobile && (
              <IconButton onClick={() => setDrawerOpen(true)} edge="start">
                <MenuIcon />
              </IconButton>
            )}
            <Avatar sx={{ bgcolor: 'primary.main' }}>
              <SmartToy />
            </Avatar>
            <Box>
              <Typography variant="h6" fontWeight="600">
                {t('interface.assistantTitle')}
              </Typography>
              <Typography variant="caption" color="text.secondary">
                {t('interface.assistantSubtitle')}
              </Typography>
            </Box>
          </Box>
        </Paper>

        {/* Messages Container */}
        <Box
          sx={{
            flex: 1,
            overflowY: 'auto',
            p: 2,
            display: 'flex',
            flexDirection: 'column',
            gap: 2,
          }}
        >
          {messages.length === 0 && (
            <Box
              sx={{
                flex: 1,
                display: 'flex',
                flexDirection: 'column',
                alignItems: 'center',
                justifyContent: 'center',
                gap: 3,
              }}
            >
              <AutoAwesome sx={{ fontSize: 64, color: 'primary.main', opacity: 0.5 }} />
              <Typography variant="h6" color="text.secondary" textAlign="center">
                {t('interface.greeting', { name: user?.name })}
              </Typography>
              <Box
                sx={{
                  display: 'flex',
                  flexWrap: 'wrap',
                  gap: 1,
                  justifyContent: 'center',
                  maxWidth: 600,
                }}
              >
                {suggestedQuestions.map((question, index) => (
                  <Chip
                    key={index}
                    label={question}
                    onClick={() => handleSuggestedQuestion(question)}
                    sx={{
                      py: 2,
                      borderRadius: 2,
                      fontSize: '0.875rem',
                      bgcolor: 'background.paper',
                      border: 1,
                      borderColor: 'divider',
                      '&:hover': {
                        bgcolor: 'primary.light',
                        borderColor: 'primary.main',
                      },
                    }}
                  />
                ))}
              </Box>
            </Box>
          )}

          <AnimatePresence>
            {messages.map((message) => (
              <motion.div
                key={message.id}
                initial={{ opacity: 0, y: 20 }}
                animate={{ opacity: 1, y: 0 }}
                exit={{ opacity: 0 }}
                transition={{ duration: 0.3 }}
              >
                <Box
                  sx={{
                    display: 'flex',
                    gap: 2,
                    justifyContent: message.role === 'user' ? 'flex-end' : 'flex-start',
                  }}
                >
                  {message.role === 'assistant' && (
                    <Avatar sx={{ bgcolor: 'primary.main', mt: 1 }}>
                      <SmartToy />
                    </Avatar>
                  )}
                  <Paper
                    elevation={0}
                    sx={{
                      p: 2,
                      maxWidth: '70%',
                      borderRadius: 3,
                      bgcolor:
                        message.role === 'user'
                          ? 'primary.main'
                          : 'rgba(255, 255, 255, 0.95)',
                      color: message.role === 'user' ? 'white' : 'text.primary',
                      backdropFilter: 'blur(10px)',
                    }}
                  >
                    {message.role === 'assistant' ? (
                      <>
                        <Box
                          sx={{
                            '& p': { mb: 1 },
                            '& strong': { fontWeight: 600 },
                            '& ul, & ol': { pl: 2, mb: 1 },
                            '& li': { mb: 0.5 },
                            '& hr': { my: 2, borderColor: 'divider' },
                            '& h1, & h2, & h3, & h4, & h5, & h6': {
                              fontWeight: 600,
                              mb: 1,
                              mt: 1.5
                            },
                          }}
                        >
                          <ReactMarkdown remarkPlugins={[remarkGfm]}>
                            {message.content}
                          </ReactMarkdown>
                        </Box>
                        <Typography
                          variant="caption"
                          sx={{
                            mt: 1,
                            display: 'block',
                            opacity: 0.7,
                          }}
                        >
                          {message.timestamp.toLocaleTimeString()}
                        </Typography>
                        <MessageFeedback
                          messageId={message.id}
                          conversationId={currentConversationId}
                        />
                      </>
                    ) : (
                      <>
                        <Typography variant="body1" sx={{ whiteSpace: 'pre-wrap' }}>
                          {message.content}
                        </Typography>
                        <Typography
                          variant="caption"
                          sx={{
                            mt: 1,
                            display: 'block',
                            opacity: 0.7,
                          }}
                        >
                          {message.timestamp.toLocaleTimeString()}
                        </Typography>
                      </>
                    )}
                  </Paper>
                  {message.role === 'user' && (
                    <Avatar sx={{ bgcolor: 'secondary.main', mt: 1 }}>
                      <Person />
                    </Avatar>
                  )}
                </Box>
              </motion.div>
            ))}
          </AnimatePresence>

          {/* Streaming Message Display */}
          {streamingMessage && (
            <motion.div
              initial={{ opacity: 0, y: 20 }}
              animate={{ opacity: 1, y: 0 }}
              transition={{ duration: 0.3 }}
            >
              <Box sx={{ display: 'flex', gap: 2, justifyContent: 'flex-start' }}>
                <Avatar sx={{ bgcolor: 'primary.main', mt: 1 }}>
                  <SmartToy />
                </Avatar>
                <Paper
                  elevation={0}
                  sx={{
                    p: 2,
                    maxWidth: '70%',
                    borderRadius: 3,
                    bgcolor: 'rgba(255, 255, 255, 0.95)',
                    backdropFilter: 'blur(10px)',
                  }}
                >
                  <Box
                    sx={{
                      '& p': { mb: 1 },
                      '& strong': { fontWeight: 600 },
                      '& ul, & ol': { pl: 2, mb: 1 },
                      '& li': { mb: 0.5 },
                      '& hr': { my: 2, borderColor: 'divider' },
                      '& h1, & h2, & h3, & h4, & h5, & h6': {
                        fontWeight: 600,
                        mb: 1,
                        mt: 1.5
                      },
                    }}
                  >
                    <ReactMarkdown remarkPlugins={[remarkGfm]}>
                      {streamingMessage}
                    </ReactMarkdown>
                    <Box
                      component="span"
                      sx={{
                        display: 'inline-block',
                        width: '2px',
                        height: '1.2em',
                        bgcolor: 'primary.main',
                        ml: 0.5,
                        verticalAlign: 'text-bottom',
                        animation: 'blink 1s infinite',
                        '@keyframes blink': {
                          '0%, 49%': { opacity: 1 },
                          '50%, 100%': { opacity: 0 },
                        },
                      }}
                    />
                  </Box>
                </Paper>
              </Box>
            </motion.div>
          )}

          {/* Loading Indicator (shown when waiting for first token) */}
          {isLoading && !streamingMessage && (
            <Box sx={{ display: 'flex', gap: 2 }}>
              <Avatar sx={{ bgcolor: 'primary.main' }}>
                <SmartToy />
              </Avatar>
              <Paper
                elevation={0}
                sx={{
                  p: 2,
                  borderRadius: 3,
                  bgcolor: 'rgba(255, 255, 255, 0.95)',
                  display: 'flex',
                  alignItems: 'center',
                  gap: 1,
                }}
              >
                <CircularProgress size={20} />
                <Typography
                  variant="body2"
                  color="text.secondary"
                  sx={{
                    transition: 'opacity 0.3s ease-in-out',
                  }}
                >
                  {currentThinkingMessages[currentThinkingIndex] || t('chat.thinking')}
                </Typography>
              </Paper>
            </Box>
          )}

          <div ref={messagesEndRef} />
        </Box>

        {/* Input Area */}
        <Paper
          elevation={0}
          sx={{
            p: 2,
            borderRadius: 0,
            background: 'rgba(255, 255, 255, 0.95)',
            backdropFilter: 'blur(10px)',
            borderTop: '1px solid',
            borderColor: 'divider',
          }}
        >
          <Box sx={{ display: 'flex', gap: 1, alignItems: 'flex-end' }}>
            <TextField
              fullWidth
              multiline
              maxRows={4}
              placeholder={t('interface.inputPlaceholder')}
              value={input}
              onChange={(e) => setInput(e.target.value)}
              onKeyPress={(e) => {
                if (e.key === 'Enter' && !e.shiftKey) {
                  e.preventDefault();
                  handleSend();
                }
              }}
              disabled={isLoading}
              sx={{
                '& .MuiOutlinedInput-root': {
                  borderRadius: 3,
                  bgcolor: 'background.default',
                  '&:hover fieldset': { borderColor: 'primary.main' },
                  '&.Mui-focused fieldset': { borderColor: 'primary.main' }
                },
              }}
            />
            <IconButton
              color="primary"
              onClick={() => handleSend()}
              disabled={!input.trim() || isLoading}
              sx={{
                width: 48,
                height: 48,
                bgcolor: 'primary.main',
                color: 'white',
                '&:hover': {
                  bgcolor: 'primary.dark',
                },
                '&:disabled': {
                  bgcolor: 'action.disabledBackground',
                },
              }}
            >
              <Send />
            </IconButton>
          </Box>
          <Typography variant="caption" color="text.secondary" sx={{ mt: 1, display: 'block' }}>
            {t('interface.disclaimerFooter')}
          </Typography>
        </Paper>
      </Box>

      {/* Delete Confirmation Dialog */}
      <Dialog open={deleteDialogOpen} onClose={() => setDeleteDialogOpen(false)}>
        <DialogTitle>{t('interface.deleteDialogTitle')}</DialogTitle>
        <DialogContent>
          <Typography>
            {t('interface.deleteDialogMessage')}
          </Typography>
        </DialogContent>
        <DialogActions>
          <Button onClick={() => setDeleteDialogOpen(false)}>{t('interface.cancel')}</Button>
          <Button onClick={handleDeleteConversation} color="error" variant="contained">
            {t('interface.delete')}
          </Button>
        </DialogActions>
      </Dialog>

      {/* Context Menu for Conversation Actions */}
      <Menu
        open={contextMenu !== null}
        onClose={handleCloseContextMenu}
        anchorReference="anchorPosition"
        anchorPosition={
          contextMenu !== null ? { top: contextMenu.mouseY, left: contextMenu.mouseX } : undefined
        }
      >
        <MenuItem
          onClick={() => {
            if (contextMenu) {
              setMoveToGroupDialog({ open: true, conversationId: contextMenu.conversationId });
            }
            handleCloseContextMenu();
          }}
        >
          <ListItemIcon>
            <DriveFileMove fontSize="small" />
          </ListItemIcon>
          <ListItemText>{t('interface.moveToGroup')}</ListItemText>
        </MenuItem>
        <MenuItem
          onClick={() => {
            if (contextMenu) {
              setConversationToDelete(contextMenu.conversationId);
              setDeleteDialogOpen(true);
            }
            handleCloseContextMenu();
          }}
        >
          <ListItemIcon>
            <Delete fontSize="small" />
          </ListItemIcon>
          <ListItemText>{t('interface.delete')}</ListItemText>
        </MenuItem>
      </Menu>

      {/* Move to Group Dialog */}
      <Dialog
        open={moveToGroupDialog.open}
        onClose={() => setMoveToGroupDialog({ open: false, conversationId: null })}
        maxWidth="xs"
        fullWidth
      >
        <DialogTitle>{t('interface.moveToGroup')}</DialogTitle>
        <DialogContent>
          <List>
            <ListItemButton
              onClick={() => {
                if (moveToGroupDialog.conversationId) {
                  handleMoveToGroup(moveToGroupDialog.conversationId, null);
                }
              }}
            >
              <ListItemIcon>
                <Chat />
              </ListItemIcon>
              <ListItemText primary={t('interface.ungrouped')} />
            </ListItemButton>
            <Divider />
            {getExistingGroups().map((groupName) => (
              <ListItemButton
                key={groupName}
                onClick={() => {
                  if (moveToGroupDialog.conversationId) {
                    handleMoveToGroup(moveToGroupDialog.conversationId, groupName);
                  }
                }}
              >
                <ListItemIcon>
                  <Folder />
                </ListItemIcon>
                <ListItemText primary={groupName} />
              </ListItemButton>
            ))}
            <Divider />
            <ListItemButton onClick={() => setNewGroupDialog(true)}>
              <ListItemIcon>
                <CreateNewFolder />
              </ListItemIcon>
              <ListItemText primary={t('interface.createNewGroup')} />
            </ListItemButton>
          </List>
        </DialogContent>
        <DialogActions>
          <Button onClick={() => setMoveToGroupDialog({ open: false, conversationId: null })}>
            {t('interface.cancel')}
          </Button>
        </DialogActions>
      </Dialog>

      {/* Create New Group Dialog */}
      <Dialog
        open={newGroupDialog}
        onClose={() => {
          setNewGroupDialog(false);
          setNewGroupName('');
        }}
        maxWidth="xs"
        fullWidth
      >
        <DialogTitle>{t('interface.createNewGroup')}</DialogTitle>
        <DialogContent>
          <TextField
            autoFocus
            margin="dense"
            label={t('interface.groupNameLabel')}
            fullWidth
            variant="outlined"
            value={newGroupName}
            onChange={(e) => setNewGroupName(e.target.value)}
            onKeyPress={(e) => {
              if (e.key === 'Enter') {
                handleCreateNewGroup();
              }
            }}
          />
        </DialogContent>
        <DialogActions>
          <Button
            onClick={() => {
              setNewGroupDialog(false);
              setNewGroupName('');
            }}
          >
            {t('interface.cancel')}
          </Button>
          <Button onClick={handleCreateNewGroup} variant="contained" disabled={!newGroupName.trim()}>
            {t('interface.create')}
          </Button>
        </DialogActions>
      </Dialog>
    </Box>
  );
};