'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,
} from '@mui/material';
import {
  Send,
  SmartToy,
  Person,
  AutoAwesome,
  Chat,
  Delete,
  Add,
  Menu as MenuIcon,
  Close,
} 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';

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;
}

const suggestedQuestions = [
  'How much should my baby sleep at 3 months?',
  'What are normal feeding patterns?',
  'When should I introduce solid foods?',
  'Tips for better sleep routine',
];

const thinkingMessages = [
  'Gathering baby wisdom...',
  'Consulting the baby books...',
  'Mixing up the perfect answer...',
  'Warming up some advice...',
  'Preparing your bottle of knowledge...',
  'Counting tiny fingers and toes...',
  'Connecting the building blocks...',
  'Peeking into the toy box...',
  'Arranging the puzzle pieces...',
  'Stirring the baby food jar...',
  'Polishing the pacifier of wisdom...',
  'Tiptoeing through naptime...',
  'Organizing the diaper bag...',
  'Wrapping up your answer with love...',
  'Brewing a warm cup of guidance...',
  'Knitting together some thoughts...',
  'Tucking in the details...',
  'Sprinkling some magic dust...',
  'Humming a lullaby while I think...',
];

// 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);
};

export const AIChatInterface: React.FC = () => {
  const [messages, setMessages] = useState<Message[]>([]);
  const [input, setInput] = useState('');
  const [isLoading, setIsLoading] = useState(false);
  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 messagesEndRef = useRef<HTMLDivElement>(null);
  const thinkingIntervalRef = useRef<NodeJS.Timeout | null>(null);
  const { user } = useAuth();
  const theme = useTheme();
  const isMobile = useMediaQuery(theme.breakpoints.down('md'));

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

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

  // 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);
    }
  };

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

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

    setMessages((prev) => [...prev, userMessage]);
    setInput('');
    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: 'Sorry, I encountered an error. Please try again.',
        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">
            Chat History
          </Typography>
          {isMobile && (
            <IconButton onClick={() => setDrawerOpen(false)} size="small">
              <Close />
            </IconButton>
          )}
        </Box>
        <Button
          fullWidth
          variant="contained"
          startIcon={<Add />}
          onClick={handleNewConversation}
          sx={{ borderRadius: 2 }}
        >
          New Chat
        </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">
              No conversations yet
            </Typography>
          </Box>
        ) : (
          conversations.map((conversation) => (
            <ListItem key={conversation.id} disablePadding>
              <ListItemButton
                selected={conversation.id === currentConversationId}
                onClick={() => loadConversation(conversation.id)}
                sx={{
                  mx: 1,
                  borderRadius: 2,
                  mb: 0.5,
                  '&.Mui-selected': {
                    bgcolor: 'primary.light',
                    '&:hover': {
                      bgcolor: 'primary.light',
                    },
                  },
                }}
              >
                <ListItemIcon>
                  <Chat />
                </ListItemIcon>
                <ListItemText
                  primary={conversation.title}
                  secondary={new Date(conversation.createdAt).toLocaleDateString()}
                  primaryTypographyProps={{
                    noWrap: true,
                    fontWeight: conversation.id === currentConversationId ? 600 : 400,
                  }}
                  secondaryTypographyProps={{
                    variant: 'caption',
                  }}
                />
                <IconButton
                  size="small"
                  onClick={(e) => {
                    e.stopPropagation();
                    setConversationToDelete(conversation.id);
                    setDeleteDialogOpen(true);
                  }}
                  sx={{ ml: 1 }}
                >
                  <Delete fontSize="small" />
                </IconButton>
              </ListItemButton>
            </ListItem>
          ))
        )}
      </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">
                AI Parenting Assistant
              </Typography>
              <Typography variant="caption" color="text.secondary">
                Ask me anything about parenting and childcare
              </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">
                Hi {user?.name}! How can I help you today?
              </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={{
                      borderRadius: 3,
                      '&:hover': {
                        bgcolor: 'primary.light',
                        color: 'white',
                      },
                    }}
                  />
                ))}
              </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="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>

          {isLoading && (
            <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] || '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="Ask me anything..."
              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,
                },
              }}
            />
            <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' }}>
            This AI assistant provides general information. Always consult healthcare professionals
            for medical advice.
          </Typography>
        </Paper>
      </Box>

      {/* Delete Confirmation Dialog */}
      <Dialog open={deleteDialogOpen} onClose={() => setDeleteDialogOpen(false)}>
        <DialogTitle>Delete Conversation</DialogTitle>
        <DialogContent>
          <Typography>
            Are you sure you want to delete this conversation? This action cannot be undone.
          </Typography>
        </DialogContent>
        <DialogActions>
          <Button onClick={() => setDeleteDialogOpen(false)}>Cancel</Button>
          <Button onClick={handleDeleteConversation} color="error" variant="contained">
            Delete
          </Button>
        </DialogActions>
      </Dialog>
    </Box>
  );
};