import React, { useState, useEffect } from 'react';
import '../style/Admin.css';
import { Select, message, Table } from 'antd';
import { fetchUserList, giveUser, giveAdmin, giveSuperAdmin } from '../api/posts';

const { Option } = Select;
const ROLE_LIST = ['用户', '管理员', '超级管理员'];

function UserManagement({ superAdminId }) {
  const [users, setUsers] = useState([]);

  useEffect(() => {
    async function load() {
      try {
        const data = superAdminId
          ? await fetchUserList(superAdminId)
          : await fetch('/api/users').then(res => res.json());
        setUsers(data);
      } catch (e) {
        console.error(e);
      }
    }
    load();
  }, [superAdminId]);

  // handle role changes
  const handleRoleChange = async (userId, newRole) => {
    try {
      if (newRole === '用户') await giveUser(superAdminId, userId);
      else if (newRole === '管理员') await giveAdmin(superAdminId, userId);
      else if (newRole === '超级管理员') await giveSuperAdmin(superAdminId, userId);
      setUsers(us => us.map(u => u.id === userId ? { ...u, role: newRole } : u));
      message.success('修改成功');
    } catch (e) {
      console.error(e);
      message.error('修改失败');
    }
  };

  // define table columns
  const columns = [
    { title: '用户名', dataIndex: 'username', key: 'username' },
    { title: '角色', dataIndex: 'role', key: 'role' },
    {
      title: '操作',
      key: 'action',
      render: (_, record) => {
        const orderedRoles = [record.role, ...ROLE_LIST.filter(r => r !== record.role)];
        return (
          <Select
            value={record.role}
            style={{ width: 120 }}
            onChange={value => handleRoleChange(record.id, value)}
          >
            {orderedRoles.map(r => (
              <Option key={r} value={r}>{r}</Option>
            ))}
          </Select>
        );
      },
    },
  ];

  return (
    <div className="admin-container">
      <Table
        dataSource={users}
        columns={columns}
        rowKey="id"
        pagination={false}
      />
    </div>
  );
}

export default UserManagement;