import { useEffect, useState } from 'react'
import {
  Alert, Button, Card, Form, Input, InputNumber, Modal, Popconfirm, Space,
  Switch, Table, Tabs, Tag, Tooltip, Typography, message, Select,
} from 'antd'
import type { ColumnsType } from 'antd/es/table'
import { CloudServerOutlined, PlusOutlined } from '@ant-design/icons'
import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
import { useTranslation } from 'react-i18next'

import apiClient, { isEnvelope } from '../../api/client'
import { useAuthStore } from '../../stores/auth'
import PageHeader from '../../components/PageHeader'

const { Text } = Typography

interface DHCPSettings {
  id: number
  enabled: boolean
  default_lease: number
  max_lease: number
  domain_name: string
  dns_servers: string
}
interface DHCPSubnet {
  id: number
  name: string
  interface_name: string
  subnet_cidr: string
  pool_start: string
  pool_end: string
  gateway: string
  dns_servers: string
  lease_time?: number | null
  active: boolean
  description: string
}
interface DHCPReservation {
  id: number
  subnet_id: number
  name: string
  mac_address: string
  ip_address: string
  hostname: string
  active: boolean
}
interface NetIface { name: string; role: string }

export default function DHCPPage() {
  const { t } = useTranslation()
  return (
    <div>
      <PageHeader icon={<CloudServerOutlined />} title={t('dhcp.title')} subtitle={t('dhcp.intro')} />
      <Tabs
        defaultActiveKey="settings"
        items={[
          { key: 'settings', label: t('dhcp.tabs.settings'), children: <SettingsTab /> },
          { key: 'subnets', label: t('dhcp.tabs.subnets'), children: <SubnetsTab /> },
        ]}
      />
    </div>
  )
}

// ── Settings ─────────────────────────────────────────────────────────

function SettingsTab() {
  const { t } = useTranslation()
  const qc = useQueryClient()
  const isViewer = useAuthStore((s) => s.user?.role) === 'viewer'
  const [msg, msgCtx] = message.useMessage()
  const [form] = Form.useForm<DHCPSettings>()

  const { data } = useQuery({
    queryKey: ['dhcp', 'settings'],
    queryFn: async () => {
      const r = await apiClient.get('/dhcp/settings')
      return isEnvelope(r.data) ? (r.data.data as DHCPSettings) : null
    },
  })
  useEffect(() => { if (data) form.setFieldsValue(data) }, [data, form])

  const save = useMutation({
    mutationFn: async (v: DHCPSettings) => apiClient.put('/dhcp/settings', v),
    onSuccess: () => {
      msg.success(t('dhcp.saved'))
      void qc.invalidateQueries({ queryKey: ['dhcp', 'settings'] })
    },
    onError: (e: Error) => msg.error(t('dhcp.saveFailed') + ': ' + e.message),
  })

  return (
    <Card size="small">
      {msgCtx}
      <Alert
        type="warning"
        showIcon
        className="mb-16"
        message={t('dhcp.haWarnTitle')}
        description={t('dhcp.haWarnDesc')}
      />
      <Form<DHCPSettings> form={form} layout="vertical" onFinish={(v) => save.mutate(v)}>
        <Form.Item label={t('dhcp.settings.enabled')} name="enabled" valuePropName="checked">
          <Switch disabled={isViewer} />
        </Form.Item>
        <Form.Item label={t('dhcp.settings.defaultLease')} name="default_lease">
          <InputNumber min={60} style={{ width: 240 }} disabled={isViewer} />
        </Form.Item>
        <Form.Item label={t('dhcp.settings.maxLease')} name="max_lease">
          <InputNumber min={60} style={{ width: 240 }} disabled={isViewer} />
        </Form.Item>
        <Form.Item label={t('dhcp.settings.domainName')} name="domain_name">
          <Input placeholder="lan" disabled={isViewer} />
        </Form.Item>
        <Form.Item label={t('dhcp.settings.dnsServers')} name="dns_servers" extra={t('dhcp.csvHint')}>
          <Input placeholder="1.1.1.1, 8.8.8.8" disabled={isViewer} />
        </Form.Item>
        <Form.Item style={{ marginBottom: 0 }}>
          <Tooltip title={isViewer ? t('auth.viewerBadge') : undefined}>
            <Button type="primary" htmlType="submit" loading={save.isPending} disabled={isViewer}>
              {t('common.save')}
            </Button>
          </Tooltip>
        </Form.Item>
      </Form>
    </Card>
  )
}

// ── Subnets ──────────────────────────────────────────────────────────

function SubnetsTab() {
  const { t } = useTranslation()
  const qc = useQueryClient()
  const isViewer = useAuthStore((s) => s.user?.role) === 'viewer'
  const [msg, msgCtx] = message.useMessage()
  const [form] = Form.useForm<DHCPSubnet>()
  const [editing, setEditing] = useState<DHCPSubnet | null>(null)
  const [open, setOpen] = useState(false)
  const [resvFor, setResvFor] = useState<DHCPSubnet | null>(null)

  const { data: subnets } = useQuery({
    queryKey: ['dhcp', 'subnets'],
    queryFn: async () => {
      const r = await apiClient.get('/dhcp/subnets')
      return isEnvelope(r.data) ? ((r.data.data as { subnets?: DHCPSubnet[] }).subnets ?? []) : []
    },
  })
  const { data: ifaces } = useQuery({
    queryKey: ['network-interfaces'],
    queryFn: async () => {
      const r = await apiClient.get('/network-interfaces')
      return isEnvelope(r.data) ? ((r.data.data as { interfaces?: NetIface[] }).interfaces ?? []) : []
    },
  })

  const save = useMutation({
    mutationFn: async (v: DHCPSubnet) => {
      if (editing) return apiClient.put(`/dhcp/subnets/${editing.id}`, v)
      return apiClient.post('/dhcp/subnets', v)
    },
    onSuccess: () => {
      msg.success(t('dhcp.saved'))
      setOpen(false); setEditing(null)
      void qc.invalidateQueries({ queryKey: ['dhcp', 'subnets'] })
    },
    onError: (e: Error) => msg.error(t('dhcp.saveFailed') + ': ' + e.message),
  })
  const del = useMutation({
    mutationFn: async (id: number) => apiClient.delete(`/dhcp/subnets/${id}`),
    onSuccess: () => {
      msg.success(t('dhcp.deleted'))
      void qc.invalidateQueries({ queryKey: ['dhcp', 'subnets'] })
    },
    onError: (e: Error) => msg.error(t('dhcp.deleteFailed') + ': ' + e.message),
  })

  const openNew = () => {
    setEditing(null)
    form.resetFields()
    form.setFieldsValue({ active: true } as Partial<DHCPSubnet>)
    setOpen(true)
  }
  const openEdit = (s: DHCPSubnet) => {
    setEditing(s)
    form.setFieldsValue(s)
    setOpen(true)
  }

  const cols: ColumnsType<DHCPSubnet> = [
    { title: t('dhcp.subnet.name'), dataIndex: 'name' },
    { title: t('dhcp.subnet.interface'), dataIndex: 'interface_name' },
    { title: t('dhcp.subnet.cidr'), dataIndex: 'subnet_cidr' },
    {
      title: t('dhcp.subnet.pool'), key: 'pool',
      render: (_, r) => (r.pool_start && r.pool_end ? `${r.pool_start} – ${r.pool_end}` : '—'),
    },
    { title: t('dhcp.subnet.gateway'), dataIndex: 'gateway', render: (v) => v || '—' },
    {
      title: t('common.status'), dataIndex: 'active',
      render: (v: boolean) => <Tag color={v ? 'green' : 'default'}>{v ? t('common.active') : t('common.inactive')}</Tag>,
    },
    {
      title: t('common.actions'), key: 'actions', width: 280,
      render: (_, r) => (
        <Space>
          <Button size="small" onClick={() => setResvFor(r)}>{t('dhcp.reservations')}</Button>
          {!isViewer && <Button size="small" onClick={() => openEdit(r)}>{t('common.edit')}</Button>}
          {!isViewer && (
            <Popconfirm title={t('dhcp.subnet.deleteConfirm', { name: r.name })} onConfirm={() => del.mutate(r.id)}>
              <Button size="small" danger>{t('common.delete')}</Button>
            </Popconfirm>
          )}
        </Space>
      ),
    },
  ]

  return (
    <Card size="small">
      {msgCtx}
      <Space style={{ marginBottom: 12 }}>
        <Button type="primary" icon={<PlusOutlined />} onClick={openNew} disabled={isViewer}>
          {t('dhcp.subnet.add')}
        </Button>
      </Space>
      <Table<DHCPSubnet> rowKey="id" size="small" columns={cols} dataSource={subnets ?? []} pagination={false} />

      <Modal
        title={editing ? t('dhcp.subnet.edit') : t('dhcp.subnet.add')}
        open={open}
        onCancel={() => setOpen(false)}
        onOk={() => form.submit()}
        confirmLoading={save.isPending}
        destroyOnClose
      >
        <Form<DHCPSubnet> form={form} layout="vertical" onFinish={(v) => save.mutate(v)}>
          <Form.Item label={t('dhcp.subnet.name')} name="name" rules={[{ required: true }]}>
            <Input />
          </Form.Item>
          <Form.Item label={t('dhcp.subnet.interface')} name="interface_name" rules={[{ required: true }]}>
            <Select
              options={(ifaces ?? []).map((i) => ({ value: i.name, label: `${i.name} (${i.role})` }))}
              showSearch
            />
          </Form.Item>
          <Form.Item label={t('dhcp.subnet.cidr')} name="subnet_cidr" rules={[{ required: true }]}>
            <Input placeholder="10.0.0.0/24" />
          </Form.Item>
          <Space>
            <Form.Item label={t('dhcp.subnet.poolStart')} name="pool_start">
              <Input placeholder="10.0.0.100" />
            </Form.Item>
            <Form.Item label={t('dhcp.subnet.poolEnd')} name="pool_end">
              <Input placeholder="10.0.0.200" />
            </Form.Item>
          </Space>
          <Form.Item label={t('dhcp.subnet.gateway')} name="gateway">
            <Input placeholder="10.0.0.1" />
          </Form.Item>
          <Form.Item label={t('dhcp.subnet.dnsServers')} name="dns_servers" extra={t('dhcp.csvHint')}>
            <Input placeholder="1.1.1.1, 8.8.8.8" />
          </Form.Item>
          <Form.Item label={t('dhcp.subnet.active')} name="active" valuePropName="checked">
            <Switch />
          </Form.Item>
        </Form>
      </Modal>

      {resvFor && (
        <ReservationsModal subnet={resvFor} onClose={() => setResvFor(null)} />
      )}
    </Card>
  )
}

// ── Reservations (per subnet) ────────────────────────────────────────

function ReservationsModal({ subnet, onClose }: { subnet: DHCPSubnet; onClose: () => void }) {
  const { t } = useTranslation()
  const qc = useQueryClient()
  const isViewer = useAuthStore((s) => s.user?.role) === 'viewer'
  const [msg, msgCtx] = message.useMessage()
  const [form] = Form.useForm<DHCPReservation>()
  const [editing, setEditing] = useState<DHCPReservation | null>(null)
  const [formOpen, setFormOpen] = useState(false)

  const key = ['dhcp', 'reservations', subnet.id]
  const { data } = useQuery({
    queryKey: key,
    queryFn: async () => {
      const r = await apiClient.get(`/dhcp/subnets/${subnet.id}/reservations`)
      return isEnvelope(r.data) ? ((r.data.data as { reservations?: DHCPReservation[] }).reservations ?? []) : []
    },
  })

  const save = useMutation({
    mutationFn: async (v: DHCPReservation) => {
      if (editing) return apiClient.put(`/dhcp/reservations/${editing.id}`, v)
      return apiClient.post(`/dhcp/subnets/${subnet.id}/reservations`, v)
    },
    onSuccess: () => {
      msg.success(t('dhcp.saved'))
      setFormOpen(false); setEditing(null)
      void qc.invalidateQueries({ queryKey: key })
    },
    onError: (e: Error) => msg.error(t('dhcp.saveFailed') + ': ' + e.message),
  })
  const del = useMutation({
    mutationFn: async (id: number) => apiClient.delete(`/dhcp/reservations/${id}`),
    onSuccess: () => {
      msg.success(t('dhcp.deleted'))
      void qc.invalidateQueries({ queryKey: key })
    },
    onError: (e: Error) => msg.error(t('dhcp.deleteFailed') + ': ' + e.message),
  })

  const cols: ColumnsType<DHCPReservation> = [
    { title: t('dhcp.reservation.mac'), dataIndex: 'mac_address' },
    { title: t('dhcp.reservation.ip'), dataIndex: 'ip_address' },
    { title: t('dhcp.reservation.hostname'), dataIndex: 'hostname', render: (v) => v || '—' },
    {
      title: t('common.actions'), key: 'actions', width: 180,
      render: (_, r) => (
        <Space>
          {!isViewer && <Button size="small" onClick={() => { setEditing(r); form.setFieldsValue(r); setFormOpen(true) }}>{t('common.edit')}</Button>}
          {!isViewer && (
            <Popconfirm title={t('dhcp.reservation.deleteConfirm')} onConfirm={() => del.mutate(r.id)}>
              <Button size="small" danger>{t('common.delete')}</Button>
            </Popconfirm>
          )}
        </Space>
      ),
    },
  ]

  return (
    <Modal
      title={`${t('dhcp.reservations')} — ${subnet.name}`}
      open
      onCancel={onClose}
      footer={null}
      width={640}
    >
      {msgCtx}
      <Space style={{ marginBottom: 12 }}>
        <Button
          type="primary" icon={<PlusOutlined />} disabled={isViewer}
          onClick={() => { setEditing(null); form.resetFields(); form.setFieldsValue({ active: true } as Partial<DHCPReservation>); setFormOpen(true) }}
        >
          {t('dhcp.reservation.add')}
        </Button>
      </Space>
      <Table<DHCPReservation> rowKey="id" size="small" columns={cols} dataSource={data ?? []} pagination={false} />

      <Modal
        title={editing ? t('dhcp.reservation.edit') : t('dhcp.reservation.add')}
        open={formOpen}
        onCancel={() => setFormOpen(false)}
        onOk={() => form.submit()}
        confirmLoading={save.isPending}
        destroyOnClose
      >
        <Form<DHCPReservation> form={form} layout="vertical" onFinish={(v) => save.mutate(v)}>
          <Form.Item label={t('dhcp.reservation.name')} name="name">
            <Input />
          </Form.Item>
          <Form.Item label={t('dhcp.reservation.mac')} name="mac_address" rules={[{ required: true }]}>
            <Input placeholder="aa:bb:cc:dd:ee:ff" />
          </Form.Item>
          <Form.Item label={t('dhcp.reservation.ip')} name="ip_address" rules={[{ required: true }]}>
            <Input placeholder="10.0.0.50" />
          </Form.Item>
          <Form.Item label={t('dhcp.reservation.hostname')} name="hostname">
            <Input />
          </Form.Item>
          <Form.Item label={t('dhcp.subnet.active')} name="active" valuePropName="checked">
            <Switch />
          </Form.Item>
        </Form>
      </Modal>
      <Text type="secondary" style={{ fontSize: 12 }}>{subnet.subnet_cidr}</Text>
    </Modal>
  )
}