import 'antd/dist/antd.css';
import React, { useState, useEffect, useMemo, useCallback } from 'react';
import { Layout, Tabs, Input, List, Card, Button, Tag, Spin, Typography, Divider } from 'antd';
import '../style/Admin.css';
import { fetchPosts, approvePost, rejectPost } from '../api/posts';

export default function Admin() {
  const ADMIN_USER_ID = 2;
  const [posts, setPosts] = useState([]);
  const [loading, setLoading] = useState(true);
  const [hasPermission, setHasPermission] = useState(true);
  const [activeTab, setActiveTab] = useState('all');
  const [selectedPost, setSelectedPost] = useState(null);
  const [searchTerm, setSearchTerm] = useState('');
  
  // 新增：拖拽相关状态
  const [leftPanelWidth, setLeftPanelWidth] = useState(300);
  const [isResizing, setIsResizing] = useState(false);

  const statusColors = {
    draft: 'orange',
    pending: 'blue',
    published: 'green',
    deleted: 'gray',
    rejected: 'red'
  };

  useEffect(() => {
    async function load() {
      try {
        const list = await fetchPosts(ADMIN_USER_ID)
        setPosts(list)
      } catch (e) {
        if (e.message === 'Unauthorized') {
          setHasPermission(false)
        } else {
          console.error(e)
        }
      } finally {
        setLoading(false)
      }
    }
    load()
  }, [])

  // 过滤并排序
  const sortedPosts = useMemo(() => {
    return [...posts].sort((a, b) => {
      if (a.status === 'pending' && b.status !== 'pending') return -1
      if (b.status === 'pending' && a.status !== 'pending') return 1
      return 0
    })
  }, [posts])

  // 调整：根据 activeTab 及搜索关键词过滤
  const filteredPosts = useMemo(() => {
    let list
    switch (activeTab) {
      case 'pending':
        list = sortedPosts.filter(p => p.status === 'pending'); break
      case 'published':
        list = sortedPosts.filter(p => p.status === 'published'); break
      case 'rejected':
        list = sortedPosts.filter(p => p.status === 'rejected'); break
      default:
        list = sortedPosts
    }
    return list.filter(p =>
      p.title.toLowerCase().includes(searchTerm.toLowerCase())
    )
  }, [sortedPosts, activeTab, searchTerm])

  const handleApprove = async id => {
    await approvePost(id, ADMIN_USER_ID)
    setPosts(ps => ps.map(x => x.id === id ? { ...x, status: 'published' } : x))
    // 同步更新选中的帖子状态
    if (selectedPost?.id === id) {
      setSelectedPost(prev => ({ ...prev, status: 'published' }));
    }
  }
  const handleReject  = async id => {
    await rejectPost(id, ADMIN_USER_ID)
    setPosts(ps => ps.map(x => x.id === id ? { ...x, status: 'rejected' } : x))
    // 同步更新选中的帖子状态
    if (selectedPost?.id === id) {
      setSelectedPost(prev => ({ ...prev, status: 'rejected' }));
    }
  }
  const handleSelect  = post => setSelectedPost(post)

  // 修复：拖拽处理函数
  const handleMouseMove = useCallback((e) => {
    if (!isResizing) return;
    
    const newWidth = e.clientX;
    const minWidth = 200;
    const maxWidth = window.innerWidth - 300;
    
    if (newWidth >= minWidth && newWidth <= maxWidth) {
      setLeftPanelWidth(newWidth);
    }
  }, [isResizing]);

  const handleMouseUp = useCallback(() => {
    setIsResizing(false);
    document.removeEventListener('mousemove', handleMouseMove);
    document.removeEventListener('mouseup', handleMouseUp);
    document.body.style.cursor = '';
    document.body.style.userSelect = '';
  }, [handleMouseMove]);

  const handleMouseDown = useCallback((e) => {
    e.preventDefault();
    setIsResizing(true);
    document.addEventListener('mousemove', handleMouseMove);
    document.addEventListener('mouseup', handleMouseUp);
    document.body.style.cursor = 'col-resize';
    document.body.style.userSelect = 'none';
  }, [handleMouseMove, handleMouseUp]);

  // 新增：组件卸载时清理事件监听器
  useEffect(() => {
    return () => {
      document.removeEventListener('mousemove', handleMouseMove);
      document.removeEventListener('mouseup', handleMouseUp);
      document.body.style.cursor = '';
      document.body.style.userSelect = '';
    };
  }, [handleMouseMove, handleMouseUp]);

  if (loading) return <Spin spinning tip="加载中…" style={{ width: '100%', marginTop: 100 }} />;
  if (!hasPermission) return <div style={{ textAlign: 'center', marginTop: 100 }}>权限不足</div>;

  const { Content } = Layout;
  const { TabPane } = Tabs;
  const { Title, Text } = Typography;

  return (
    <div style={{ height: '100vh', display: 'flex' }}>
      {/* 左侧面板 */}
      <div 
        style={{ 
          width: leftPanelWidth,
          background: '#fff', 
          padding: 16,
          borderRight: '1px solid #f0f0f0',
          overflow: 'hidden'
        }}
      >
        <div style={{ marginBottom: 24 }}>
          <Title level={3}>小红书</Title>
          <Input.Search
            placeholder="搜索帖子标题..."
            value={searchTerm}
            onChange={e => setSearchTerm(e.target.value)}
            enterButton
          />
        </div>
        <Tabs activeKey={activeTab} onChange={key => { setActiveTab(key); setSelectedPost(null); }}>
          <TabPane tab="全部" key="all" />
          <TabPane tab="待审核" key="pending" />
          <TabPane tab="已通过" key="published" />
          <TabPane tab="已驳回" key="rejected" />
        </Tabs>
        <div style={{ height: 'calc(100vh - 200px)', overflow: 'auto' }}>
          <List
            dataSource={filteredPosts}
            pagination={{
              pageSize: 5,
              showSizeChanger: true,
              pageSizeOptions: ['5','10','20'],
              onChange: () => setSelectedPost(null)
            }}
            renderItem={p => (
              <List.Item
                key={p.id}
                style={{
                  background: selectedPost?.id === p.id ? '#e6f7ff' : '',
                  cursor: 'pointer',
                  marginBottom: 8
                }}
                onClick={() => handleSelect(p)}
              >
                <List.Item.Meta
                  avatar={
                    p.thumbnail && (
                      <img
                        src={p.thumbnail}
                        alt=""
                        style={{ width: 64, height: 64, objectFit: 'cover' }}
                      />
                    )
                  }
                  title={p.title}
                  description={`${p.createdAt} · ${p.author} · ${p.likes || 0}赞`}
                />
                <Tag color={statusColors[p.status]}>{p.status}</Tag>
              </List.Item>
            )}
          />
        </div>
      </div>

      {/* 拖拽分割条 */}
      <div
        style={{
          width: 5,
          cursor: 'col-resize',
          background: isResizing ? '#1890ff' : '#f0f0f0',
          transition: isResizing ? 'none' : 'background-color 0.2s',
          position: 'relative',
          flexShrink: 0
        }}
        onMouseDown={handleMouseDown}
        onSelectStart={(e) => e.preventDefault()}
      >
        <div
          style={{
            position: 'absolute',
            top: '50%',
            left: '50%',
            transform: 'translate(-50%, -50%)',
            width: 2,
            height: 20,
            background: '#999',
            borderRadius: 1
          }}
        />
      </div>

      {/* 右侧内容区域 */}
      <div style={{ flex: 1, display: 'flex', flexDirection: 'column' }}>
        <Content style={{ padding: 24, background: '#fff', overflow: 'auto' }}>
          {selectedPost ? (
            <Card
              cover={selectedPost.image && <img alt="cover" src={selectedPost.image} />}
              title={selectedPost.title}
              extra={
                <div>
                  {selectedPost.status === 'pending' && (
                    <>
                      <Button type="primary" onClick={() => handleApprove(selectedPost.id)}>通过</Button>
                      <Button danger onClick={() => handleReject(selectedPost.id)}>驳回</Button>
                    </>
                  )}
                  {selectedPost.status === 'published' && (
                    <Button danger onClick={() => handleReject(selectedPost.id)}>驳回</Button>
                  )}
                  {selectedPost.status === 'rejected' && (
                    <>
                      <Button onClick={() => {
                        setPosts(ps => ps.map(x => x.id === selectedPost.id ? { ...x, status: 'pending' } : x));
                        setSelectedPost(prev => ({ ...prev, status: 'pending' }));
                      }}>恢复待审</Button>
                      <Button onClick={() => {
                        setPosts(ps => ps.map(x => x.id === selectedPost.id ? { ...x, status: 'published' } : x));
                        setSelectedPost(prev => ({ ...prev, status: 'published' }));
                      }}>恢复已发</Button>
                    </>
                  )}
                </div>
              }
            >
              <Text type="secondary">
                {`${selectedPost.createdAt} · ${selectedPost.author} · ${selectedPost.likes || 0}赞`}
              </Text>
              <Divider />
              <p>{selectedPost.content}</p>
              <Divider />
              <Title level={4}>合规性指引</Title>
              <ul>
                <li>不含违法违规内容</li>
                <li>不侵害他人合法权益</li>
              </ul>
            </Card>
          ) : (
            <Text type="secondary">请选择左侧列表中的帖子查看详情</Text>
          )}
        </Content>
      </div>
    </div>
  );
}