import React, { useEffect, useMemo, useState } from 'react';
import { Table, Button, Input, Space, Drawer, Form, Select, App, Tooltip, Tag } from 'antd';
import {
  PlusOutlined,
  EditOutlined,
  DeleteOutlined,
  KeyOutlined,
  SaveOutlined,
  SearchOutlined,
  UserOutlined,
  MailOutlined,
  SafetyCertificateOutlined,
  ReloadOutlined,
} from '@ant-design/icons';
import apiClient from '../../utils/apiClient';
import { buildApiUrl, API_ENDPOINTS } from '../../config/api';
import configService from '../../utils/configService';
import AdminModuleShell from '../../components/AdminModuleShell';

const UserManagement = () => {
  const { message, modal } = App.useApp();
  const [form] = Form.useForm();

  const [users, setUsers] = useState([]);
  const [total, setTotal] = useState(0);
  const [page, setPage] = useState(1);
  const [pageSize, setPageSize] = useState(10);
  const [loading, setLoading] = useState(true);
  const [showUserDrawer, setShowUserDrawer] = useState(false);
  const [isEditing, setIsEditing] = useState(false);
  const [currentUser, setCurrentUser] = useState(null);
  const [roles, setRoles] = useState([]);
  const [searchText, setSearchText] = useState('');
  const [debouncedSearchText, setDebouncedSearchText] = useState('');

  useEffect(() => {
    configService.getPageSize().then((size) => {
      const safeSize = Number.isFinite(size) ? Math.min(100, Math.max(5, size)) : 10;
      setPageSize(safeSize);
    });
    fetchRoles();
  }, []);

  useEffect(() => {
    const timer = setTimeout(() => {
      setDebouncedSearchText(searchText.trim());
      setPage(1);
    }, 300);

    return () => clearTimeout(timer);
  }, [searchText]);

  useEffect(() => {
    fetchUsers();
  }, [page, pageSize, debouncedSearchText]);

  const fetchUsers = async () => {
    setLoading(true);
    try {
      let url = `${API_ENDPOINTS.USERS.LIST}?page=${page}&size=${pageSize}`;
      if (debouncedSearchText) {
        url += `&search=${encodeURIComponent(debouncedSearchText)}`;
      }
      const response = await apiClient.get(buildApiUrl(url));
      setUsers(response.data.users || []);
      setTotal(response.data.total || 0);
    } catch {
      message.error('无法加载用户列表');
    } finally {
      setLoading(false);
    }
  };

  const fetchRoles = async () => {
    try {
      const response = await apiClient.get(buildApiUrl(API_ENDPOINTS.USERS.ROLES));
      setRoles(response.data || []);
    } catch {
      setRoles([
        { role_id: 1, role_name: '平台管理员' },
        { role_id: 2, role_name: '普通用户' },
      ]);
    }
  };

  const handleOpenModal = (user = null) => {
    if (user) {
      setIsEditing(true);
      setCurrentUser(user);
      form.setFieldsValue(user);
    } else {
      setIsEditing(false);
      setCurrentUser(null);
      form.resetFields();
      form.setFieldsValue({ role_id: 2 });
    }
    setShowUserDrawer(true);
  };

  const handleSave = async () => {
    try {
      const values = await form.validateFields();
      if (isEditing) {
        await apiClient.put(buildApiUrl(API_ENDPOINTS.USERS.UPDATE(currentUser.user_id)), values);
        message.success('用户修改成功');
      } else {
        await apiClient.post(buildApiUrl(API_ENDPOINTS.USERS.CREATE), values);
        message.success('用户添加成功');
      }
      setShowUserDrawer(false);
      fetchUsers();
    } catch (err) {
      if (err.response) {
        message.error(err.response.data?.message || '操作失败');
      }
    }
  };

  const handleDelete = (user) => {
    modal.confirm({
      title: '删除用户',
      content: `确定要删除用户"${user.caption}"吗？此操作无法撤销。`,
      okText: '确定删除',
      okType: 'danger',
      cancelText: '取消',
      onOk: async () => {
        try {
          await apiClient.delete(buildApiUrl(API_ENDPOINTS.USERS.DELETE(user.user_id)));
          message.success('用户删除成功');
          fetchUsers();
        } catch {
          message.error('删除失败');
        }
      },
    });
  };

  const handleResetPassword = (user) => {
    modal.confirm({
      title: '重置密码',
      content: `确定要重置用户"${user.caption}"的密码吗？重置后密码将恢复为系统默认密码。`,
      okText: '确定重置',
      cancelText: '取消',
      onOk: async () => {
        try {
          await apiClient.post(buildApiUrl(API_ENDPOINTS.USERS.RESET_PASSWORD(user.user_id)));
          message.success('密码重置成功');
        } catch {
          message.error('重置失败');
        }
      },
    });
  };

  const roleNameById = useMemo(() => {
    return roles.reduce((map, role) => {
      map[role.role_id] = role.role_name;
      return map;
    }, {});
  }, [roles]);

  const adminCountOnPage = useMemo(
    () => users.filter((user) => String(user.role_id) === '1' || user.role_name?.includes('管理员')).length,
    [users],
  );

  const columns = [
    { title: 'ID', dataIndex: 'user_id', key: 'user_id', width: 80 },
    { title: '用户名', dataIndex: 'username', key: 'username' },
    { title: '姓名', dataIndex: 'caption', key: 'caption' },
    { title: '邮箱', dataIndex: 'email', key: 'email' },
    {
      title: '角色',
      dataIndex: 'role_name',
      key: 'role_name',
      render: (text, record) => {
        const roleName = text || roleNameById[record.role_id] || '-';
        return <Tag color={String(record.role_id) === '1' ? 'blue' : 'default'}>{roleName}</Tag>;
      },
    },
    {
      title: '创建时间',
      dataIndex: 'created_at',
      key: 'created_at',
      render: (text) => (text ? new Date(text).toLocaleString() : '-'),
    },
    {
      title: '操作',
      key: 'action',
      fixed: 'right',
      width: 150,
      render: (_, record) => (
        <Space size="middle">
          <Tooltip title="修改">
            <Button type="text" className="btn-text-edit" icon={<EditOutlined />} onClick={() => handleOpenModal(record)} />
          </Tooltip>
          <Tooltip title="重置密码">
            <Button type="text" className="btn-text-accent" icon={<KeyOutlined />} onClick={() => handleResetPassword(record)} />
          </Tooltip>
          <Tooltip title="删除">
            <Button type="text" danger className="btn-text-delete" icon={<DeleteOutlined />} onClick={() => handleDelete(record)} />
          </Tooltip>
        </Space>
      ),
    },
  ];

  return (
    <div className="user-management">
      <AdminModuleShell
        icon={<SafetyCertificateOutlined style={{ fontSize: 18, color: '#1d4ed8' }} />}
        title="用户管理"
        subtitle="管理账号信息、角色分配与密码恢复。支持快速搜索和分页配置。"
        rightActions={
          <Space>
            <Button icon={<ReloadOutlined />} className="btn-soft-blue" onClick={fetchUsers} loading={loading}>刷新</Button>
            <Button type="primary" icon={<PlusOutlined />} onClick={() => handleOpenModal()}>
              新增用户
            </Button>
          </Space>
        }
        stats={[
          { label: '总用户数', value: total },
          { label: '当前页', value: `${users.length}/${pageSize}` },
          { label: '管理员(页内)', value: adminCountOnPage },
        ]}
        toolbar={
          <Input
            placeholder="搜索用户名、姓名或邮箱..."
            prefix={<SearchOutlined />}
            value={searchText}
            onChange={(e) => setSearchText(e.target.value)}
            style={{ maxWidth: 320 }}
            allowClear
          />
        }
      >
        <div className="console-table">
          <Table
            columns={columns}
            dataSource={users}
            loading={loading}
            pagination={{
              current: page,
              pageSize,
              total,
              onChange: (nextPage, size) => {
                setPage(nextPage);
                setPageSize(size);
              },
              showSizeChanger: true,
              showTotal: (count) => `共 ${count} 条记录`,
            }}
            rowKey="user_id"
            scroll={{ x: 900 }}
          />
        </div>
      </AdminModuleShell>

      <Drawer
        open={showUserDrawer}
        title={isEditing ? '编辑用户' : '新增用户'}
        placement="right"
        width={520}
        onClose={() => setShowUserDrawer(false)}
        destroyOnClose
        extra={(
          <Space>
            <Button type="primary" icon={<SaveOutlined />} onClick={handleSave}>
              {isEditing ? '保存修改' : '创建用户'}
            </Button>
          </Space>
        )}
      >
        <Form form={form} layout="vertical" style={{ marginTop: 20 }} initialValues={{ role_id: 2 }}>
          <Form.Item name="username" label="用户名" rules={[{ required: true, message: '请输入用户名' }]}>
            <Input prefix={<UserOutlined />} placeholder="请输入用户名" />
          </Form.Item>
          <Form.Item name="caption" label="姓名" rules={[{ required: true, message: '请输入姓名' }]}>
            <Input prefix={<UserOutlined />} placeholder="请输入姓名" />
          </Form.Item>
          <Form.Item
            name="email"
            label="邮箱"
            rules={[
              { required: true, message: '请输入邮箱' },
              { type: 'email', message: '请输入有效的邮箱地址' },
            ]}
          >
            <Input prefix={<MailOutlined />} placeholder="请输入邮箱" />
          </Form.Item>
          <Form.Item name="role_id" label="角色" rules={[{ required: true, message: '请选择角色' }]}>
            <Select
              options={roles.map((role) => ({
                label: role.role_name,
                value: role.role_id,
              }))}
            />
          </Form.Item>
          {!isEditing && (
            <div style={{ color: 'rgba(0,0,0,0.45)', fontSize: 12 }}>
              注：新用户默认使用系统初始化密码，首次登录后建议立即修改。
            </div>
          )}
        </Form>
      </Drawer>
    </div>
  );
};

export default UserManagement;