/**
 * 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 } from 'react';
import {
  View,
  FlatList,
  StyleSheet,
  TouchableOpacity,
  ActivityIndicator,
  KeyboardAvoidingView,
  Platform,
  TextInput,
  Dimensions,
} from 'react-native';
import { useNavigation } from '@react-navigation/native';
import { MaterialCommunityIcons } from '@expo/vector-icons';
import { colors, spacing, fontSizes, shadows } from '../../../theme';
import { ConversationResponse, MessageResponse, MessageSegment } from '../../../types/dto';
import { Avatar, Text } from '../../../components/common';
import { useAuthStore, messageManager, MessageEvent, MessageSubscriber } from '../../../stores';
import { extractTextFromSegments } from '../../../types/dto';

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

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

export const EmbeddedChat: React.FC<EmbeddedChatProps> = ({ conversation, onBack }) => {
  const navigation = useNavigation();
  const currentUser = useAuthStore(state => state.currentUser);
  
  // 状态
  const [messages, setMessages] = useState<MessageResponse[]>([]);
  const [loading, setLoading] = useState(true);
  const [sending, setSending] = useState(false);
  const [inputText, setInputText] = useState('');
  const flatListRef = useRef<FlatList>(null);
  const inputRef = useRef<TextInput>(null);
  
  // 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));
      setMessages(messageManager.getMessages(String(conversation.id)));
    } catch (error) {
      console.error('[EmbeddedChat] 加载消息失败:', error);
    } finally {
      setLoading(false);
    }
  }, [conversation.id]);
  
  // 初始加载
  useEffect(() => {
    loadMessages();
    
    // 订阅消息事件
    const subscriber: MessageSubscriber = (event: MessageEvent) => {
      if (
        event.type === 'messages_updated' &&
        String(event.payload?.conversationId) === String(conversation.id)
      ) {
        setMessages(event.payload.messages || []);
        setTimeout(() => {
          flatListRef.current?.scrollToEnd({ animated: true });
        }, 100);
      }
    };
    
    const unsubscribe = messageManager.subscribe(subscriber);
    
    return () => {
      unsubscribe();
    };
  }, [conversation.id, loadMessages]);
  
  // 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) {
      (navigation as any).navigate('Chat', {
        conversationId: String(conversation.id),
        groupId: String(conversation.group.id),
        groupName: conversation.group.name,
        isGroupChat: true,
      });
    } else {
      const currentUserId = currentUser?.id;
      const otherUser = conversation.participants?.find(p => String(p.id) !== String(currentUserId));
      (navigation as any).navigate('Chat', {
        conversationId: String(conversation.id),
        userId: otherUser ? String(otherUser.id) : undefined,
        userName: otherUser?.nickname || otherUser?.username,
        isGroupChat: false,
      });
    }
  };
  
  // 渲染消息
  const renderMessage = ({ item }: { item: MessageResponse }) => {
    const isMe = String(item.sender_id) === String(currentUser?.id);
    
    return (
      <View style={[styles.messageRow, isMe ? styles.messageRowRight : styles.messageRowLeft]}>
        {!isMe && (
          <Avatar 
            source={item.sender?.avatar} 
            size={36} 
            name={item.sender?.nickname || item.sender?.username} 
          />
        )}
        <View style={[styles.messageBubble, isMe ? styles.messageBubbleMe : styles.messageBubbleOther]}>
          {isGroupChat && !isMe && (
            <Text style={styles.senderName}>{item.sender?.nickname || item.sender?.username}</Text>
          )}
          <Text style={[styles.messageText, isMe ? styles.messageTextMe : styles.messageTextOther]}>
            {item.status === 'recalled' ? '消息已撤回' : extractTextFromSegments(item.segments)}
          </Text>
        </View>
        {isMe && (
          <Avatar 
            source={currentUser?.avatar} 
            size={36} 
            name={currentUser?.nickname || currentUser?.username} 
          />
        )}
      </View>
    );
  };
  
  return (
    <View style={styles.container}>
      {/* 头部 */}
      <View style={styles.header}>
        <TouchableOpacity onPress={onBack} style={styles.headerButton}>
          <MaterialCommunityIcons name="arrow-left" size={24} color="#666" />
        </TouchableOpacity>
        
        <View style={styles.headerCenter}>
          <Avatar source={chatAvatar} size={36} name={chatTitle} />
          <Text style={styles.headerTitle} numberOfLines={1}>
            {chatTitle}
          </Text>
        </View>
        
        <TouchableOpacity onPress={handleNavigateToFullChat} style={styles.headerButton}>
          <MaterialCommunityIcons name="arrow-expand" size={22} color="#666" />
        </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="#DDD" />
            <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}>
              <MaterialCommunityIcons name="plus-circle-outline" size={28} color="#666" />
            </TouchableOpacity>
            
            <View style={styles.inputContainer}>
              <TextInput
                ref={inputRef}
                style={styles.textInput}
                placeholder="发送消息..."
                placeholderTextColor="#999"
                value={inputText}
                onChangeText={setInputText}
                multiline={false}
                returnKeyType="send"
                onSubmitEditing={handleSend}
                blurOnSubmit={false}
              />
            </View>
            
            <TouchableOpacity style={styles.iconButton}>
              <MaterialCommunityIcons name="emoticon-outline" size={28} color="#666" />
            </TouchableOpacity>
            
            <TouchableOpacity 
              style={[styles.sendButton, (!inputText.trim() || sending) && styles.sendButtonDisabled]}
              onPress={handleSend}
              disabled={!inputText.trim() || sending}
            >
              {sending ? (
                <ActivityIndicator size="small" color="#FFF" />
              ) : (
                <MaterialCommunityIcons name="send" size={20} color="#FFF" />
              )}
            </TouchableOpacity>
          </View>
        </View>
      </KeyboardAvoidingView>
    </View>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#F5F7FA',
  },
  header: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'space-between',
    paddingHorizontal: spacing.md,
    paddingVertical: spacing.sm,
    backgroundColor: '#FFF',
    borderBottomWidth: 1,
    borderBottomColor: '#E8E8E8',
    ...shadows.sm,
    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: '#333',
    marginLeft: spacing.sm,
    maxWidth: 200,
  },
  messageList: {
    flex: 1,
    backgroundColor: '#F5F7FA',
  },
  centerContainer: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
    padding: spacing.xl,
  },
  emptyText: {
    marginTop: spacing.md,
    fontSize: 16,
    color: '#999',
  },
  emptySubtext: {
    marginTop: spacing.xs,
    fontSize: 14,
    color: '#BBB',
  },
  listContent: {
    padding: spacing.md,
    paddingBottom: spacing.xl,
  },
  messageRow: {
    flexDirection: 'row',
    alignItems: 'flex-end',
    marginBottom: spacing.md,
    maxWidth: screenWidth * 0.7,
  },
  messageRowLeft: {
    alignSelf: 'flex-start',
  },
  messageRowRight: {
    alignSelf: 'flex-end',
    flexDirection: 'row-reverse',
  },
  messageBubble: {
    maxWidth: screenWidth * 0.5,
    paddingHorizontal: spacing.md,
    paddingVertical: spacing.sm,
    borderRadius: 18,
    marginHorizontal: spacing.sm,
  },
  messageBubbleMe: {
    backgroundColor: colors.primary.main,
    borderBottomRightRadius: 4,
  },
  messageBubbleOther: {
    backgroundColor: '#FFF',
    borderBottomLeftRadius: 4,
    ...shadows.sm,
  },
  senderName: {
    fontSize: 12,
    color: '#999',
    marginBottom: 2,
  },
  messageText: {
    fontSize: 15,
    lineHeight: 20,
  },
  messageTextMe: {
    color: '#FFF',
  },
  messageTextOther: {
    color: '#333',
  },
  inputArea: {
    backgroundColor: '#FFF',
    borderTopWidth: 1,
    borderTopColor: '#E8E8E8',
    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: '#F5F5F5',
    borderRadius: 20,
    paddingHorizontal: spacing.md,
    minHeight: 40,
    justifyContent: 'center',
  },
  textInput: {
    fontSize: 15,
    color: '#333',
    padding: 0,
    maxHeight: 100,
  },
  sendButton: {
    width: 40,
    height: 40,
    borderRadius: 20,
    backgroundColor: colors.primary.main,
    alignItems: 'center',
    justifyContent: 'center',
    marginLeft: spacing.xs,
  },
  sendButtonDisabled: {
    backgroundColor: '#E0E0E0',
  },
});