import { useCallback, useEffect, useMemo, useState } from 'react'
import { Button, Form, Input, Modal, Popconfirm, Space, Switch, Table, Tabs, Tag, Typography, message } from 'antd'
import { DeleteOutlined, EditOutlined, PlusOutlined, ReloadOutlined } from '@ant-design/icons'
import type { ColumnsType } from 'antd/es/table'
import { platformApi, userApi } from '../api'
import { PageHeader } from '../components/PageHeader'
import type { MerchantMember, MerchantMemberGroup, PageResult, User } from '../types'
import { formatDateTime } from '../utils/time'
import { useAuth } from '../store/auth'
import { roleText } from './merchantCenterUtils'
import { useNavigate } from 'react-router-dom'

type AdminFormValues = {
  username: string
  nickname?: string
  password?: string
  status: boolean
}

export default function PlatformUsers() {
  const { user: currentUser } = useAuth()
  const navigate = useNavigate()
  const [tab, setTab] = useState('admins')
  const [admins, setAdmins] = useState<PageResult<User>>({ list: [], total: 0, page: 1, size: 20 })
  const [merchantAccounts, setMerchantAccounts] = useState<PageResult<MerchantMemberGroup>>({ list: [], total: 0, page: 1, size: 20 })
  const [loading, setLoading] = useState(false)
  const [submitting, setSubmitting] = useState(false)
  const [editingAdmin, setEditingAdmin] = useState<User | null>(null)
  const [modalOpen, setModalOpen] = useState(false)
  const [form] = Form.useForm<AdminFormValues>()

  const loadAdmins = useCallback(async (page = admins.page, size = admins.size) => {
    setLoading(true)
    try {
      setAdmins(await userApi.list({ page, size }))
    } catch (e) {
      message.error(e instanceof Error ? e.message : '加载失败')
    } finally {
      setLoading(false)
    }
  }, [admins.page, admins.size])

  const loadMerchantAccounts = useCallback(async (page = merchantAccounts.page, size = merchantAccounts.size) => {
    setLoading(true)
    try {
      setMerchantAccounts(await platformApi.merchantAccounts({ page, size }))
    } catch (e) {
      message.error(e instanceof Error ? e.message : '加载失败')
    } finally {
      setLoading(false)
    }
  }, [merchantAccounts.page, merchantAccounts.size])

  useEffect(() => {
    if (tab === 'admins') void loadAdmins()
    else void loadMerchantAccounts()
  }, [loadAdmins, loadMerchantAccounts, tab])

  const openCreate = () => {
    setEditingAdmin(null)
    form.setFieldsValue({ username: '', nickname: '', password: '', status: true })
    setModalOpen(true)
  }

  const openEdit = (record: User) => {
    setEditingAdmin(record)
    form.setFieldsValue({ username: record.username, nickname: record.nickname, password: '', status: record.status === 1 })
    setModalOpen(true)
  }

  const submit = async () => {
    const values = await form.validateFields()
    setSubmitting(true)
    try {
      if (editingAdmin) {
        await userApi.update(editingAdmin.id, {
          username: values.username,
          nickname: values.nickname || '',
          password: values.password || undefined,
          status: values.status ? 1 : 0,
        })
        message.success('平台管理员已更新')
      } else {
        await userApi.create({ username: values.username, password: values.password || '', nickname: values.nickname || '' })
        message.success('平台管理员已创建')
      }
      setModalOpen(false)
      form.resetFields()
      void loadAdmins(editingAdmin ? admins.page : 1)
    } catch (e) {
      message.error(e instanceof Error ? e.message : editingAdmin ? '更新失败' : '创建失败')
    } finally {
      setSubmitting(false)
    }
  }

  const remove = async (record: User) => {
    try {
      await userApi.remove(record.id)
      message.success('平台管理员已删除')
      void loadAdmins()
    } catch (e) {
      message.error(e instanceof Error ? e.message : '删除失败')
    }
  }

  const columns: ColumnsType<User> = [
    { title: '用户名', dataIndex: 'username', width: 260, render: (value) => <Typography.Text strong>{value}</Typography.Text> },
    { title: '昵称', dataIndex: 'nickname', width: 220, render: (value) => value || '-' },
    { title: '状态', dataIndex: 'status', width: 120, render: (value) => value === 1 ? <Tag color="green">启用</Tag> : <Tag>停用</Tag> },
    { title: '创建时间', dataIndex: 'created_at', width: 190, render: formatDateTime },
    {
      title: '操作',
      width: 190,
      render: (_, record) => record.id === currentUser?.id ? <Typography.Text type="secondary">当前账号</Typography.Text> : (
        <Space size={0}>
          <Button type="link" size="small" icon={<EditOutlined />} onClick={() => openEdit(record)}>编辑</Button>
          <Popconfirm title={`确认删除平台管理员「${record.username}」？`} description="删除后无法登录平台，且不会影响任何商户员工。" onConfirm={() => remove(record)} okButtonProps={{ danger: true }}>
            <Button type="link" danger size="small" icon={<DeleteOutlined />}>删除</Button>
          </Popconfirm>
        </Space>
      ),
    },
  ]

  const memberColumns: ColumnsType<MerchantMember> = [
    { title: '员工账号', dataIndex: ['user', 'username'], width: 260, render: (_, record) => <Typography.Text strong>{record.user?.username || `#${record.user_id}`}</Typography.Text> },
    { title: '昵称', dataIndex: ['user', 'nickname'], width: 220, render: (_, record) => record.user?.nickname || '-' },
    { title: '商户角色', dataIndex: 'role', width: 160, render: (role) => <Tag color="blue">{roleText(role)}</Tag> },
    { title: '成员状态', dataIndex: 'status', width: 130, render: (status) => status === 1 ? <Tag color="green">启用</Tag> : <Tag>停用</Tag> },
  ]

  const merchantColumns: ColumnsType<MerchantMemberGroup> = [
    {
      title: '商户',
      width: 320,
      render: (_, record) => <Space direction="vertical" size={0}><Typography.Text strong>{record.merchant?.name || `商户#${record.merchant_id}`}</Typography.Text><Typography.Text type="secondary" style={{ fontSize: 12 }}>{record.merchant?.code || '-'}</Typography.Text></Space>,
    },
    { title: '下游账号', width: 130, render: (_, record) => `${record.members.length} 个` },
    {
      title: '角色分布',
      render: (_, record) => {
        const roles = [...new Set(record.members.map((member) => member.role))]
        return <Space size={[4, 4]} wrap>{roles.map((role) => <Tag color="blue" key={role}>{roleText(role)}</Tag>)}</Space>
      },
    },
    {
      title: '操作',
      width: 160,
      render: (_, record) => <Button type="link" size="small" onClick={() => {
        localStorage.setItem('merchant_id', String(record.merchant_id))
        navigate('/merchant-members')
      }}>管理商户成员</Button>,
    },
  ]

  const items = useMemo(() => [
    {
      key: 'admins',
      label: `平台管理员 (${admins.total})`,
      children: <Table
        rowKey="id"
        loading={loading}
        columns={columns}
        dataSource={admins.list}
        pagination={{ current: admins.page, pageSize: admins.size, total: admins.total, showSizeChanger: true, onChange: (page, size) => void loadAdmins(page, size) }}
      />,
    },
    {
      key: 'merchant-accounts',
      label: `商户账号 (${merchantAccounts.total})`,
      children: <Table
        rowKey="merchant_id"
        loading={loading}
        columns={merchantColumns}
        dataSource={merchantAccounts.list}
        expandable={{
          expandedRowRender: (record) => <Table rowKey="id" size="small" columns={memberColumns} dataSource={record.members} pagination={false} />,
          rowExpandable: (record) => record.members.length > 0,
        }}
        pagination={{ current: merchantAccounts.page, pageSize: merchantAccounts.size, total: merchantAccounts.total, showSizeChanger: true, onChange: (page, size) => void loadMerchantAccounts(page, size) }}
      />,
    },
  ], [admins, columns, loadAdmins, loadMerchantAccounts, loading, memberColumns, merchantAccounts, merchantColumns])

  return (
    <div>
      <PageHeader
        title="账号管理"
        subtitle="平台管理员独立管理；商户账号按所属商户展示，下游员工由各商户自行维护。"
        breadcrumbs={[{ title: '账号管理' }]}
        extra={<Space><Button icon={<ReloadOutlined />} loading={loading} onClick={() => tab === 'admins' ? void loadAdmins() : void loadMerchantAccounts()}>刷新</Button>{tab === 'admins' && <Button type="primary" icon={<PlusOutlined />} onClick={openCreate}>新建平台管理员</Button>}</Space>}
      />
      <Tabs activeKey={tab} onChange={setTab} items={items} />
      <Modal
        title={editingAdmin ? '编辑平台管理员' : '新建平台管理员'}
        open={modalOpen}
        onCancel={() => setModalOpen(false)}
        onOk={() => void submit()}
        confirmLoading={submitting}
        okText="保存"
        destroyOnHidden
      >
        <Form form={form} layout="vertical" preserve={false} initialValues={{ status: true }}>
          <Form.Item label="用户名" name="username" rules={[{ required: true, message: '请输入用户名' }, { max: 64, message: '用户名不能超过 64 个字符' }]}>
            <Input autoComplete="off" />
          </Form.Item>
          <Form.Item label="昵称" name="nickname" rules={[{ max: 64, message: '昵称不能超过 64 个字符' }]}>
            <Input autoComplete="off" />
          </Form.Item>
          <Form.Item label={editingAdmin ? '新密码' : '密码'} name="password" rules={editingAdmin ? [{ min: 6, message: '密码至少 6 位' }] : [{ required: true, message: '请输入密码' }, { min: 6, message: '密码至少 6 位' }]} extra={editingAdmin ? '留空表示不修改密码' : undefined}>
            <Input.Password autoComplete="new-password" />
          </Form.Item>
          {editingAdmin && <Form.Item label="账号状态" name="status" valuePropName="checked"><Switch checkedChildren="启用" unCheckedChildren="停用" /></Form.Item>}
        </Form>
      </Modal>
    </div>
  )
}