import React, { useState, useEffect } from 'react';
import { useParams, useNavigate } from 'react-router-dom';
import { useDispatch, useSelector } from 'react-redux';
import { fetchChats, deleteChat, createChatRecord } from '../../store/chat/chat.thunks';
import { showNotification } from '../../store/notification.slice';
import ChatSidebar from './ChatSidebar';
import NewChat from './NewChat';
import ChatWindow from './ChatWindow';

export default function Chat() {
    const { knowledgeBaseId, chatId } = useParams();
    const navigate = useNavigate();
    const dispatch = useDispatch();

    // 从 Redux store 获取聊天记录列表
    const {
        items: chatHistory,
        status,
        error,
    } = useSelector((state) => state.chat.history || { items: [], status: 'idle', error: null });
    const operationStatus = useSelector((state) => state.chat.createSession?.status);
    const operationError = useSelector((state) => state.chat.createSession?.error);

    // 获取聊天记录列表
    useEffect(() => {
        dispatch(fetchChats({ page: 1, page_size: 20 }));
    }, [dispatch]);

    // 监听操作状态，显示通知
    useEffect(() => {
        if (operationStatus === 'succeeded') {
            dispatch(
                showNotification({
                    message: '操作成功',
                    type: 'success',
                })
            );
        } else if (operationStatus === 'failed' && operationError) {
            dispatch(
                showNotification({
                    message: `操作失败: ${operationError}`,
                    type: 'danger',
                })
            );
        }
    }, [operationStatus, operationError, dispatch]);

    // If we have a knowledgeBaseId but no chatId, check if we have an existing chat or create a new one
    useEffect(() => {
        if (knowledgeBaseId && !chatId) {
            // 检查是否存在包含此知识库的聊天记录
            const existingChat = chatHistory.find((chat) => {
                // 检查知识库ID是否匹配
                if (chat.datasets && Array.isArray(chat.datasets)) {
                    return chat.datasets.some((ds) => ds.id === knowledgeBaseId);
                }
                // 兼容旧格式
                if (chat.dataset_id_list && Array.isArray(chat.dataset_id_list)) {
                    return chat.dataset_id_list.includes(knowledgeBaseId.replace(/-/g, ''));
                }
                return false;
            });
            console.log('existingChat', existingChat);

            if (existingChat) {
                // 找到现有聊天记录，导航到该聊天页面
                navigate(`/chat/${knowledgeBaseId}/${existingChat.conversation_id}`);
            } else {
                // 创建新聊天
                dispatch(
                    createChatRecord({
                        dataset_id_list: [knowledgeBaseId.replace(/-/g, '')],
                        question: '选择当前知识库，创建聊天',
                    })
                )
                    .unwrap()
                    .then((response) => {
                        // 创建成功，使用返回的conversation_id导航
                        if (response && response.conversation_id) {
                            navigate(`/chat/${knowledgeBaseId}/${response.conversation_id}`);
                        } else {
                            // 错误处理
                            dispatch(
                                showNotification({
                                    message: '创建聊天失败：未能获取会话ID',
                                    type: 'danger',
                                })
                            );
                        }
                    })
                    .catch((error) => {
                        dispatch(
                            showNotification({
                                message: `创建聊天失败: ${error}`,
                                type: 'danger',
                            })
                        );
                    });
            }
        }
    }, [knowledgeBaseId, chatId, chatHistory, navigate, dispatch]);

    const handleDeleteChat = (id) => {
        // 调用 Redux action 删除聊天
        dispatch(deleteChat(id))
            .unwrap()
            .then(() => {
                // 删除成功后显示通知
                dispatch(
                    showNotification({
                        message: '聊天记录已删除',
                        type: 'success',
                    })
                );

                // If the deleted chat is the current one, navigate to the chat list
                if (chatId === id) {
                    navigate('/chat');
                }
            })
            .catch((error) => {
                // 删除失败显示错误通知
                dispatch(
                    showNotification({
                        message: `删除失败: ${error}`,
                        type: 'danger',
                    })
                );
            });
    };

    return (
        <div className='chat-container container-fluid h-100'>
            <div className='row h-100'>
                {/* Sidebar */}
                <div
                    className='col-md-3 col-lg-2 p-0 border-end'
                    style={{ height: 'calc(100vh - 73px)', overflowY: 'auto' }}
                >
                    <ChatSidebar
                        chatHistory={chatHistory}
                        onDeleteChat={handleDeleteChat}
                        isLoading={status === 'loading'}
                        hasError={status === 'failed'}
                    />
                </div>

                {/* Main Content */}
                <div
                    className='chat-main col-md-9 col-lg-10 p-0'
                    style={{ height: 'calc(100vh - 73px)', overflowY: 'auto' }}
                >
                    {!chatId ? <NewChat /> : <ChatWindow chatId={chatId} knowledgeBaseId={knowledgeBaseId} />}
                </div>
            </div>
        </div>
    );
}