/**
 * EmbeddedChat.tsx
 * 嵌入式聊天组件 - 用于桌面端双栏布局右侧
 */

import React, { useState, useEffect, useCallback, useRef, useMemo } from 'react';
import {
  View,
  FlatList,
  StyleSheet,
  TouchableOpacity,
  ActivityIndicator,
  KeyboardAvoidingView,
  Platform,
  TextInput,
  Dimensions,
  Animated,
} from 'react-native';
import { useRouter } from 'expo-router';
import { MaterialCommunityIcons } from '@expo/vector-icons';
import { Image as ExpoImage } from 'expo-image';
import { spacing, fontSizes, shadows, useAppColors, type AppColors } from '../../../theme';
import { ConversationResponse, MessageResponse, MessageSegment, GroupMemberResponse, ImageSegmentData } from '../../../types/dto';
import { Avatar, Text, ImageGallery, AppBackButton } from '../../../components/common';
import { useAuthStore, messageManager, useMessageStore } from '../../../stores';
import { formatDistanceToNow } from 'date-fns';
import { zhCN } from 'date-fns/locale';
import { extractTextFromSegments } from '../../../types/dto';
import { useBreakpointGTE } from '../../../hooks/useResponsive';
import { useMarkAsRead } from '../../../stores/messageManagerHooks';
import { messageService } from '../../../services';
import * as hrefs from '../../../navigation/hrefs';
import { GroupInfoPanel } from './ChatScreen/GroupInfoPanel';
import { LongPressMenu, MenuPosition, GroupMessage } from './ChatScreen';
import { EmojiPanel } from './ChatScreen/EmojiPanel';
import { MorePanel } from './ChatScreen/MorePanel';

const { width: screenWidth } = Dimensions.get('window');
const PANEL_WIDTH = 360;

// 时间分隔间隔（毫秒）- 5分钟
const TIME_SEPARATOR_INTERVAL = 5 * 60 * 1000;

function createEmbeddedChatStyles(colors: AppColors) {
  return StyleSheet.create({
    container: {
      flex: 1,
      backgroundColor: colors.background.default,
    },
    header: {
      flexDirection: 'row',
      alignItems: 'center',
      justifyContent: 'space-between',
      paddingHorizontal: spacing.md,
      paddingVertical: spacing.sm,
      backgroundColor: colors.background.default,
      borderBottomWidth: StyleSheet.hairlineWidth,
      borderBottomColor: colors.divider,
      shadowColor: 'transparent',
      shadowOffset: { width: 0, height: 0 },
      shadowOpacity: 0,
      shadowRadius: 0,
      elevation: 0,
      height: 56,
    },
    headerButton: {
      padding: spacing.xs,
      width: 40,
      height: 40,
      alignItems: 'center',
      justifyContent: 'center',
    },
    headerCenter: {
      flexDirection: 'row',
      alignItems: 'center',
      flex: 1,
      justifyContent: 'center',
    },
    headerTitle: {
      fontSize: fontSizes.lg,
      fontWeight: '600',
      color: colors.text.primary,
      marginLeft: spacing.sm,
      maxWidth: 200,
    },
    messageList: {
      flex: 1,
      backgroundColor: colors.background.default,
    },
    centerContainer: {
      flex: 1,
      alignItems: 'center',
      justifyContent: 'center',
      padding: spacing.xl,
    },
    emptyText: {
      marginTop: spacing.md,
      fontSize: 16,
      color: colors.text.secondary,
    },
    emptySubtext: {
      marginTop: spacing.xs,
      fontSize: 14,
      color: colors.text.disabled,
    },
    listContent: {
      padding: spacing.md,
      paddingBottom: spacing.xl,
    },
    messageRow: {
      flexDirection: 'row',
      alignItems: 'flex-start',
      marginBottom: spacing.md,
      maxWidth: screenWidth * 0.7,
    },
    messageRowLeft: {
      alignSelf: 'flex-start',
    },
    messageRowRight: {
      alignSelf: 'flex-end',
      justifyContent: 'flex-end',
      alignItems: 'flex-end',
    },
    avatarWrapper: {
      marginHorizontal: 2,
    },
    messageContent: {
      maxWidth: screenWidth * 0.5,
      marginHorizontal: spacing.xs,
      alignItems: 'flex-start',
    },
    messageBubble: {
      maxWidth: screenWidth * 0.5,
      paddingHorizontal: spacing.md,
      paddingVertical: spacing.sm,
      borderRadius: 18,
      marginHorizontal: spacing.sm,
    },
    messageBubbleMe: {
      backgroundColor: colors.chat.replyTint,
      borderTopRightRadius: 4,
    },
    messageBubbleOther: {
      backgroundColor: colors.chat.bubbleIncoming,
      borderTopLeftRadius: 4,
      shadowColor: colors.chat.shadow,
      shadowOffset: { width: 0, height: 0.5 },
      shadowOpacity: 0.04,
      shadowRadius: 1,
      elevation: 1,
    },
    senderName: {
      fontSize: 14,
      color: colors.text.secondary,
      marginBottom: 4,
      marginLeft: 4,
      fontWeight: '600',
    },
    messageText: {
      fontSize: 15,
      lineHeight: 20,
    },
    messageTextMe: {
      color: colors.chat.textPrimary,
    },
    messageTextOther: {
      color: colors.chat.textPrimary,
    },
    inputArea: {
      backgroundColor: colors.background.paper,
      borderTopWidth: StyleSheet.hairlineWidth,
      borderTopColor: colors.divider,
      paddingHorizontal: spacing.md,
      paddingVertical: spacing.sm,
      paddingBottom: Platform.OS === 'ios' ? spacing.md : spacing.sm,
    },
    inputRow: {
      flexDirection: 'row',
      alignItems: 'center',
    },
    iconButton: {
      padding: spacing.xs,
      width: 44,
      height: 44,
      alignItems: 'center',
      justifyContent: 'center',
    },
    inputContainer: {
      flex: 1,
      backgroundColor: colors.chat.surfaceInput,
      borderRadius: 20,
      paddingHorizontal: spacing.md,
      minHeight: 40,
      justifyContent: 'center',
      shadowColor: 'transparent',
      shadowOffset: { width: 0, height: 0 },
      shadowOpacity: 0,
      shadowRadius: 0,
      elevation: 0,
    },
    textInput: {
      fontSize: 15,
      color: colors.text.primary,
      padding: 0,
      maxHeight: 100,
    },
    sendButton: {
      width: 40,
      height: 40,
      borderRadius: 20,
      backgroundColor: colors.primary.main,
      alignItems: 'center',
      justifyContent: 'center',
      marginLeft: spacing.xs,
    },
    sendButtonDisabled: {
      backgroundColor: colors.background.disabled,
    },
    messageTextRecalled: {
      fontStyle: 'italic',
      color: colors.text.secondary,
    },
    imageGrid: {
      flexDirection: 'row',
      flexWrap: 'wrap',
      marginTop: 4,
    },
    messageImage: {
      borderRadius: 8,
      marginRight: 4,
      marginBottom: 4,
    },
    imagePlaceholder: {
      width: 120,
      height: 120,
      borderRadius: 8,
      backgroundColor: colors.background.disabled,
      justifyContent: 'center',
      alignItems: 'center',
      marginRight: 4,
      marginBottom: 4,
    },
    imagePlaceholderText: {
      color: colors.text.secondary,
      fontSize: 12,
      marginTop: 4,
    },
    // 时间分隔样式
    timeContainer: {
      alignItems: 'center',
      marginVertical: spacing.md,
    },
    timeText: {
      color: 'rgba(142, 142, 147, 0.95)',
      fontSize: 11,
      backgroundColor: 'rgba(142, 142, 147, 0.1)',
      paddingHorizontal: spacing.sm + 4,
      paddingVertical: 5,
      borderRadius: 12,
      fontWeight: '500',
      overflow: 'hidden',
      letterSpacing: 0.2,
    },
    // 系统通知样式（如"某某加入了群聊"）
    systemNoticeContainer: {
      alignItems: 'center',
      marginVertical: spacing.sm,
      paddingHorizontal: spacing.md,
    },
    systemNoticeText: {
      fontSize: 12,
      color: colors.chat.textSecondary,
      backgroundColor: 'rgba(142, 142, 147, 0.12)',
      paddingHorizontal: spacing.md,
      paddingVertical: spacing.xs,
      borderRadius: 12,
      overflow: 'hidden',
    },
    // 面板容器样式
    panelContainer: {
      backgroundColor: colors.background.paper,
      borderTopWidth: StyleSheet.hairlineWidth,
      borderTopColor: colors.divider,
    },
  });
}

interface EmbeddedChatProps {
  conversation: ConversationResponse;
  onBack: () => void;
}

export const EmbeddedChat: React.FC<EmbeddedChatProps> = ({ conversation, onBack }) => {
  const colors = useAppColors();
  const styles = useMemo(() => createEmbeddedChatStyles(colors), [colors]);
  const router = useRouter();
  const currentUser = useAuthStore(state => state.currentUser);
  
  // 响应式布局 - 使用 768px 作为大屏幕和小屏幕的分界线
  const isWideScreen = useBreakpointGTE('lg');
  
  // 使用 markAsRead hook
  const { markAsRead } = useMarkAsRead(String(conversation.id));
  
  // 状态 - 使用 Zustand selector 直接订阅消息
  const messages = useMessageStore(state => state.messagesMap.get(String(conversation.id)) || []);
  const [loading, setLoading] = useState(true);
  const [sending, setSending] = useState(false);
  const [inputText, setInputText] = useState('');
  const flatListRef = useRef<FlatList>(null);
  const inputRef = useRef<TextInput>(null);
  
  // 图片预览状态
  const [imageGalleryVisible, setImageGalleryVisible] = useState(false);
  const [currentImageIndex, setCurrentImageIndex] = useState(0);
  const [galleryImages, setGalleryImages] = useState<{ url: string }[]>([]);
  
  // 右键菜单状态
  const [contextMenuVisible, setContextMenuVisible] = useState(false);
  const [contextMenuPosition, setContextMenuPosition] = useState<MenuPosition | undefined>();
  const [selectedMessageForMenu, setSelectedMessageForMenu] = useState<GroupMessage | null>(null);
  
  // 回复状态
  const [replyingToMessage, setReplyingToMessage] = useState<GroupMessage | null>(null);
  
  // 面板显示状态
  const [showEmojiPanel, setShowEmojiPanel] = useState(false);
  const [showMorePanel, setShowMorePanel] = useState(false);

  // 切换表情面板
  const toggleEmojiPanel = useCallback(() => {
    setShowEmojiPanel(prev => !prev);
    setShowMorePanel(false);
    if (!showEmojiPanel) {
      inputRef.current?.blur();
    }
  }, [showEmojiPanel]);

  // 切换更多功能面板
  const toggleMorePanel = useCallback(() => {
    setShowMorePanel(prev => !prev);
    setShowEmojiPanel(false);
    if (!showMorePanel) {
      inputRef.current?.blur();
    }
  }, [showMorePanel]);

  // 关闭所有面板
  const closePanels = useCallback(() => {
    setShowEmojiPanel(false);
    setShowMorePanel(false);
  }, []);

  // 插入表情
  const handleInsertEmoji = useCallback((emoji: string) => {
    setInputText(prev => prev + emoji);
  }, []);

  // 发送自定义表情
  const handleSendSticker = useCallback(async (stickerUrl: string) => {
    if (!conversation.id) return;
    
    try {
      setSending(true);
      const segments: MessageSegment[] = [{
        type: 'image',
        data: { url: stickerUrl, thumbnail_url: stickerUrl }
      }];
      await messageManager.sendMessage(String(conversation.id), segments);
      closePanels();
    } catch (error) {
      console.error('[EmbeddedChat] 发送表情失败:', error);
    } finally {
      setSending(false);
    }
  }, [conversation.id, closePanels]);

  // 处理更多功能
  const handleMoreAction = useCallback((actionId: string) => {
    switch (actionId) {
      case 'image':
        // TODO: 实现选择图片功能
        console.log('选择图片');
        break;
      case 'camera':
        // TODO: 实现相机功能
        console.log('相机');
        break;
      case 'file':
        // TODO: 实现文件功能
        console.log('文件');
        break;
      case 'location':
        // TODO: 实现位置功能
        console.log('位置');
        break;
    }
    closePanels();
  }, [closePanels]);
  
  // 群信息面板动画
  const slideAnim = useRef(new Animated.Value(PANEL_WIDTH)).current;
  const fadeAnim = useRef(new Animated.Value(0)).current;
  const [showGroupInfoPanel, setShowGroupInfoPanel] = useState(false);
  
  // 群成员列表
  const [groupMembers, setGroupMembers] = useState<GroupMemberResponse[]>([]);
  
  // 格式化时间
  const formatTime = useCallback((dateString: string): string => {
    try {
      const date = new Date(dateString);
      const now = new Date();
      const diffInHours = (now.getTime() - date.getTime()) / (1000 * 60 * 60);

      if (diffInHours < 24 && date.getDate() === now.getDate()) {
        // 当天消息显示 "上午/下午 HH:mm" 格式
        const hours = date.getHours();
        const period = hours < 12 ? '上午' : '下午';
        const displayHours = hours % 12 || 12;
        const minutes = date.getMinutes().toString().padStart(2, '0');
        return `${period} ${displayHours}:${minutes}`;
      }

      return formatDistanceToNow(date, {
        addSuffix: true,
        locale: zhCN,
      });
    } catch {
      return '';
    }
  }, []);

  // 检查是否需要显示时间分隔
  const shouldShowTime = useCallback((index: number): boolean => {
    if (index === 0) return true;
    const currentMsg = messages[index];
    const prevMsg = messages[index - 1];
    if (!currentMsg || !prevMsg) return false;
    const currentTime = new Date(currentMsg.created_at).getTime();
    const prevTime = new Date(prevMsg.created_at).getTime();
    return (currentTime - prevTime) > TIME_SEPARATOR_INTERVAL;
  }, [messages]);
  
  // 打开/关闭群信息面板
  const toggleGroupInfoPanel = useCallback(() => {
    if (showGroupInfoPanel) {
      Animated.parallel([
        Animated.timing(slideAnim, {
          toValue: PANEL_WIDTH,
          duration: 300,
          useNativeDriver: true,
        }),
        Animated.timing(fadeAnim, {
          toValue: 0,
          duration: 300,
          useNativeDriver: true,
        }),
      ]).start(() => {
        setShowGroupInfoPanel(false);
      });
    } else {
      setShowGroupInfoPanel(true);
      Animated.parallel([
        Animated.timing(slideAnim, {
          toValue: 0,
          duration: 300,
          useNativeDriver: true,
        }),
        Animated.timing(fadeAnim, {
          toValue: 1,
          duration: 300,
          useNativeDriver: true,
        }),
      ]).start();
    }
  }, [showGroupInfoPanel, slideAnim, fadeAnim]);
  
  // 获取会话信息
  const isGroupChat = conversation.type === 'group';
  const chatTitle = isGroupChat 
    ? conversation.group?.name || '群聊'
    : conversation.participants?.[0]?.nickname || conversation.participants?.[0]?.username || '聊天';
  const chatAvatar = isGroupChat 
    ? conversation.group?.avatar 
    : conversation.participants?.[0]?.avatar;
  
  // 加载消息
  const loadMessages = useCallback(async () => {
    try {
      setLoading(true);
      await messageManager.fetchMessages(String(conversation.id));
    } catch (error: any) {
      // 检查是否是权限错误或会话不存在错误
      const errorMessage = error?.message || String(error);
      if (
        errorMessage.includes('not found') ||
        errorMessage.includes('no permission') ||
        error?.code === 'NOT_FOUND' ||
        error?.code === 'FORBIDDEN'
      ) {
        console.warn('[EmbeddedChat] 会话不存在或无权限访问:', conversation.id);
      } else {
        console.error('[EmbeddedChat] 加载消息失败:', error);
      }
    } finally {
      setLoading(false);
    }
  }, [conversation.id]);
  
  // 初始加载
  useEffect(() => {
    loadMessages();
  }, [conversation.id, loadMessages]);
  
  // 自动标记已读 - 当有新消息时
  useEffect(() => {
    if (messages.length === 0) return;
    
    const maxSeq = Math.max(...messages.map(m => m.seq), 0);
    if (maxSeq > 0) {
      markAsRead(maxSeq).catch(error => {
        console.error('[EmbeddedChat] 自动标记已读失败:', error);
      });
    }
  }, [messages, markAsRead]);
  
  // 发送消息
  const handleSend = useCallback(async () => {
    if (!inputText.trim() || sending) return;
    
    const text = inputText.trim();
    setInputText('');
    
    try {
      setSending(true);
      const segments: MessageSegment[] = [{ type: 'text', data: { text } }];
      await messageManager.sendMessage(String(conversation.id), segments);
    } catch (error) {
      console.error('[EmbeddedChat] 发送消息失败:', error);
    } finally {
      setSending(false);
    }
  }, [inputText, sending, conversation.id]);
  
  // 导航到完整聊天页面
  const handleNavigateToFullChat = () => {
    if (isGroupChat && conversation.group) {
      router.push(
        hrefs.hrefChat({
          conversationId: String(conversation.id),
          groupId: String(conversation.group.id),
          groupName: conversation.group.name,
          isGroupChat: true,
        }) as any
      );
    } else {
      const currentUserId = currentUser?.id;
      const otherUser = conversation.participants?.find(p => String(p.id) !== String(currentUserId));
      router.push(
        hrefs.hrefChat({
          conversationId: String(conversation.id),
          userId: otherUser ? String(otherUser.id) : undefined,
          isGroupChat: false,
        }) as any
      );
    }
  };
  
  // 处理图片点击预览
  const handleImagePress = (images: { url: string }[], index: number) => {
    setGalleryImages(images);
    setCurrentImageIndex(index);
    setImageGalleryVisible(true);
  };
  
  // 处理右键点击消息
  const handleMessageRightPress = (message: MessageResponse, event: any) => {
    // 获取鼠标右键位置
    const pageX = event?.nativeEvent?.pageX || 0;
    const pageY = event?.nativeEvent?.pageY || 0;
    
    setSelectedMessageForMenu(message as GroupMessage);
    setContextMenuPosition({
      x: pageX,
      y: pageY,
      width: 0,
      height: 0,
      pressX: pageX,
      pressY: pageY,
    });
    setContextMenuVisible(true);
  };
  
  // 关闭右键菜单
  const handleContextMenuClose = () => {
    setContextMenuVisible(false);
    setSelectedMessageForMenu(null);
    setContextMenuPosition(undefined);
  };
  
  // 处理回复消息
  const handleReply = (message: GroupMessage) => {
    setReplyingToMessage(message);
    handleContextMenuClose();
  };
  
  // 处理撤回消息
  const handleRecall = async (messageId: string) => {
    try {
      await messageService.recallMessage(messageId);
      handleContextMenuClose();
    } catch (error) {
      console.error('[EmbeddedChat] 撤回消息失败:', error);
    }
  };
  
  // 处理删除消息
  const handleDeleteMessage = async (messageId: string) => {
    try {
      await messageService.deleteMessage(messageId);
      handleContextMenuClose();
    } catch (error) {
      console.error('[EmbeddedChat] 删除消息失败:', error);
    }
  };
  
  // 渲染消息内容
  const renderMessageContent = (item: MessageResponse) => {
    // 撤回消息
    if (item.status === 'recalled') {
      return (
        <Text style={[styles.messageText, styles.messageTextRecalled]}>
          消息已撤回
        </Text>
      );
    }
    
    // 获取消息 segments
    const segments = item.segments || [];
    
    // 检查是否有图片消息
    const imageSegments = segments
      .filter(s => s.type === 'image')
      .map(s => s.data as ImageSegmentData);
    
    // 提取文本内容
    const textContent = extractTextFromSegments(segments);
    
    // 渲染多个内容（文本 + 图片）
    return (
      <View>
        {/* 文本内容 */}
        {textContent && textContent !== '[图片]' && (
          <Text style={[styles.messageText, item.sender_id === String(currentUser?.id) ? styles.messageTextMe : styles.messageTextOther]}>
            {textContent}
          </Text>
        )}
        
        {/* 图片内容 */}
        {imageSegments.length > 0 && (
          <View style={styles.imageGrid}>
            {imageSegments.map((imgData, idx) => {
              const imageUrl = imgData.thumbnail_url || imgData.url;
              const hasValidUrl = !!imageUrl && imageUrl.trim() !== '';
              
              if (!hasValidUrl) {
                // 无效URL显示占位符
                return (
                  <View key={`img-${item.id}-${idx}`} style={styles.imagePlaceholder}>
                    <MaterialCommunityIcons name="image" size={24} color="#999" />
                    <Text style={styles.imagePlaceholderText}>图片</Text>
                  </View>
                );
              }
              
              // 计算图片尺寸
              let width = 180;
              let height = 180;
              if (imgData.width && imgData.height) {
                const aspectRatio = imgData.width / imgData.height;
                if (aspectRatio > 1) {
                  height = width / aspectRatio;
                } else {
                  width = height * aspectRatio;
                }
              }
              
              return (
                <TouchableOpacity
                  key={`img-${item.id}-${idx}`}
                  onPress={() => handleImagePress(imageSegments.map(s => ({ url: s.thumbnail_url || s.url || '' })), idx)}
                  activeOpacity={0.8}
                >
                  <ExpoImage
                    source={{ uri: imageUrl }}
                    style={[styles.messageImage, { width, height: Math.round(height) }]}
                    contentFit="cover"
                    cachePolicy="disk"
                  />
                </TouchableOpacity>
              );
            })}
          </View>
        )}
        
        {/* 如果没有文本也没有图片，显示空消息提示 */}
        {!textContent && imageSegments.length === 0 && (
          <Text style={[styles.messageText, styles.messageTextRecalled, { opacity: 0.5 }]}>
            [消息格式错误]
          </Text>
        )}
      </View>
    );
  };
  
  // 渲染消息
  const renderMessage = ({ item, index }: { item: MessageResponse; index: number }) => {
    const isMe = String(item.sender_id) === String(currentUser?.id);
    const showTime = shouldShowTime(index);

    // 系统通知消息特殊处理
    // 1. is_system_notice 字段（WebSocket 推送时设置）
    // 2. category === 'notification'（从数据库加载时使用）
    // 3. sender_id === '10000'（系统发送者兜底）
    const isSystemNotice = (item as any).is_system_notice || item.category === 'notification' || item.sender_id === '10000';

    // 系统通知消息渲染（如"某某加入了群聊"）
    if (isSystemNotice) {
      return (
        <View>
          {showTime && (
            <View style={styles.timeContainer}>
              <Text style={styles.timeText}>
                {formatTime(item.created_at)}
              </Text>
            </View>
          )}
          <View style={styles.systemNoticeContainer}>
            <Text style={styles.systemNoticeText}>
              {(item as any).notice_content || extractTextFromSegments(item.segments)}
            </Text>
          </View>
        </View>
      );
    }

    // 处理指针事件（鼠标右键）- 使用 onPointerDown 检测鼠标右键
    const handlePointerDown = (e: any) => {
      // e.nativeEvent.button: 0=左键, 1=中键, 2=右键
      const isRightClick = e.nativeEvent?.button === 2;
      if (isRightClick) {
        // 阻止默认右键菜单
        e.preventDefault?.();
        e.stopPropagation?.();
        handleMessageRightPress(item, e);
      }
    };

    return (
      <View>
        {/* 时间分隔 */}
        {showTime && (
          <View style={styles.timeContainer}>
            <Text style={styles.timeText}>
              {formatTime(item.created_at)}
            </Text>
          </View>
        )}
        <View
          style={[styles.messageRow, isMe ? styles.messageRowRight : styles.messageRowLeft]}
          // @ts-ignore - React Native for Web 支持 pointer events
          onPointerDown={handlePointerDown}
        >
          {/* 对方头像（左侧） */}
          {!isMe && (
            <View style={styles.avatarWrapper}>
              <Avatar
                source={item.sender?.avatar}
                size={36}
                name={item.sender?.nickname || item.sender?.username}
              />
            </View>
          )}

          {/* 消息内容区域 */}
          <View style={styles.messageContent}>
            {/* 群聊模式：显示发送者昵称（在气泡上方，与头像顶部对齐） */}
            {isGroupChat && !isMe && (
              <Text style={styles.senderName}>{item.sender?.nickname || item.sender?.username}</Text>
            )}
            <View style={[styles.messageBubble, isMe ? styles.messageBubbleMe : styles.messageBubbleOther]}>
              {renderMessageContent(item)}
            </View>
          </View>

          {/* 自己的头像（右侧） */}
          {isMe && (
            <View style={styles.avatarWrapper}>
              <Avatar
                source={currentUser?.avatar}
                size={36}
                name={currentUser?.nickname || currentUser?.username}
              />
            </View>
          )}
        </View>
      </View>
    );
  };
  
  return (
    <View style={styles.container}>
      {/* 头部 */}
      <View style={styles.header}>
        {/* 大屏幕（>= 768px）时隐藏返回按钮 */}
        {!isWideScreen ? (
          <AppBackButton onPress={onBack} style={styles.headerButton} iconColor={colors.text.secondary} />
        ) : (
          <View style={styles.headerButton} />
        )}
        
        <View style={styles.headerCenter}>
          <Avatar source={chatAvatar} size={36} name={chatTitle} />
          <Text style={styles.headerTitle} numberOfLines={1}>
            {chatTitle}
          </Text>
        </View>
        
        {/* 大屏幕 + 群聊时显示群信息按钮，否则显示放大按钮 */}
        {isWideScreen && isGroupChat ? (
          <TouchableOpacity onPress={toggleGroupInfoPanel} style={styles.headerButton}>
            <MaterialCommunityIcons name="dots-horizontal" size={22} color={colors.text.secondary} />
          </TouchableOpacity>
        ) : (
          <TouchableOpacity onPress={handleNavigateToFullChat} style={styles.headerButton}>
            <MaterialCommunityIcons name="arrow-expand" size={22} color={colors.text.secondary} />
          </TouchableOpacity>
        )}
      </View>
      
      {/* 消息列表 */}
      <View style={styles.messageList}>
        {loading ? (
          <View style={styles.centerContainer}>
            <ActivityIndicator size="large" color={colors.primary.main} />
          </View>
        ) : messages.length === 0 ? (
          <View style={styles.centerContainer}>
            <MaterialCommunityIcons name="message-text-outline" size={48} color={colors.text.disabled} />
            <Text style={styles.emptyText}>暂无消息</Text>
            <Text style={styles.emptySubtext}>发送第一条消息开始聊天</Text>
          </View>
        ) : (
          <FlatList
            ref={flatListRef}
            data={messages}
            renderItem={renderMessage}
            keyExtractor={(item) => String(item.id)}
            contentContainerStyle={styles.listContent}
            showsVerticalScrollIndicator={true}
            onLayout={() => {
              if (messages.length > 0) {
                flatListRef.current?.scrollToEnd({ animated: false });
              }
            }}
          />
        )}
      </View>
      
      {/* 输入框区域 */}
      <KeyboardAvoidingView
        behavior={Platform.OS === 'ios' ? 'padding' : undefined}
        keyboardVerticalOffset={Platform.OS === 'ios' ? 90 : 0}
      >
        <View style={styles.inputArea}>
          <View style={styles.inputRow}>
            <TouchableOpacity style={styles.iconButton} onPress={toggleMorePanel}>
              <MaterialCommunityIcons 
                name={showMorePanel ? "close-circle-outline" : "plus-circle-outline"} 
                size={28} 
                color={showMorePanel ? colors.primary.main : colors.text.secondary} 
              />
            </TouchableOpacity>
            
            <View style={styles.inputContainer}>
              <TextInput
                ref={inputRef}
                style={styles.textInput}
                placeholder="发送消息..."
                placeholderTextColor={colors.text.hint}
                value={inputText}
                onChangeText={setInputText}
                multiline={false}
                returnKeyType="send"
                onSubmitEditing={handleSend}
                blurOnSubmit={false}
                // 确保光标可见
                cursorColor={colors.primary.main}
                selectionColor={`${colors.primary.main}40`}
              />
            </View>
            
            <TouchableOpacity style={styles.iconButton} onPress={toggleEmojiPanel}>
              <MaterialCommunityIcons 
                name={showEmojiPanel ? "emoticon-happy" : "emoticon-outline"} 
                size={28} 
                color={showEmojiPanel ? colors.primary.main : colors.text.secondary} 
              />
            </TouchableOpacity>
            
            <TouchableOpacity 
              style={[styles.sendButton, (!inputText.trim() || sending) && styles.sendButtonDisabled]}
              onPress={handleSend}
              disabled={!inputText.trim() || sending}
            >
              {sending ? (
                <ActivityIndicator size="small" color={colors.text.inverse} />
              ) : (
                <MaterialCommunityIcons name="send" size={20} color={colors.text.inverse} />
              )}
            </TouchableOpacity>
          </View>
        </View>
        
        {/* 表情面板 */}
        {showEmojiPanel && (
          <View style={{ height: 350, backgroundColor: colors.background.paper }}>
            <EmojiPanel
              onInsertEmoji={handleInsertEmoji}
              onInsertSticker={handleSendSticker}
              onClose={closePanels}
            />
          </View>
        )}
        
        {/* 更多功能面板 */}
        {showMorePanel && (
          <View style={{ height: 350, backgroundColor: colors.background.paper }}>
            <MorePanel
              onAction={handleMoreAction}
            />
          </View>
        )}
      </KeyboardAvoidingView>
      
      {/* 群信息侧边栏面板 - 仅大屏幕显示 */}
      {isWideScreen && isGroupChat && (
        <>
          {/* 遮罩层 */}
          {showGroupInfoPanel && (
            <Animated.View
              style={[
                StyleSheet.absoluteFillObject,
                {
                  backgroundColor: 'rgba(0, 0, 0, 0.3)',
                  opacity: fadeAnim,
                  zIndex: 100,
                },
              ]}
            >
              <TouchableOpacity
                style={StyleSheet.absoluteFillObject}
                onPress={toggleGroupInfoPanel}
                activeOpacity={1}
              />
            </Animated.View>
          )}
          
          {/* 侧边栏面板 */}
          <Animated.View
            style={[
              {
                position: 'absolute',
                right: 0,
                top: 0,
                bottom: 0,
                width: PANEL_WIDTH,
                backgroundColor: '#FFF',
                zIndex: 101,
                ...shadows.lg,
                transform: [{ translateX: slideAnim }],
              },
            ]}
          >
            <GroupInfoPanel
              visible={showGroupInfoPanel}
              groupId={conversation.group ? String(conversation.group.id) : undefined}
              groupInfo={conversation.group || null}
              currentUserId={currentUser?.id}
              onClose={toggleGroupInfoPanel}
              onTogglePin={(pinned) => {
                // TODO: 实现置顶功能
                console.log('Toggle pin:', pinned);
              }}
              onLeaveGroup={() => {
                // TODO: 实现退出群聊功能
                console.log('Leave group');
              }}
              onInviteMembers={() => {
                // TODO: 实现邀请新成员功能
                console.log('Invite members');
              }}
              onViewAllMembers={() => {
                // TODO: 实现查看全部成员功能
                console.log('View all members');
              }}
            />
          </Animated.View>
        </>
      )}
      
      {/* 右键菜单 */}
      <LongPressMenu
        visible={contextMenuVisible}
        message={selectedMessageForMenu}
        currentUserId={currentUser?.id || ''}
        position={contextMenuPosition}
        onClose={handleContextMenuClose}
        onReply={handleReply}
        onRecall={handleRecall}
        onDelete={handleDeleteMessage}
      />
      
      {/* 图片查看器 */}
      <ImageGallery
        visible={imageGalleryVisible}
        images={galleryImages.map((img, idx) => ({
          id: String(idx),
          url: img.url || ''
        }))}
        initialIndex={currentImageIndex}
        onClose={() => setImageGalleryVisible(false)}
        enableSave
      />
    </View>
  );
};