import { useState } from 'react'
import { Button, Divider, Form, Input, InputNumber, Modal, Select, Space, Switch, Tag, Tooltip, Typography, message } from 'antd'
import type { ColumnsType } from 'antd/es/table'
import { GlobalOutlined, PlusOutlined, StopOutlined, ThunderboltOutlined } from '@ant-design/icons'
import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
import { useNavigate } from 'react-router-dom'
import { useTranslation } from 'react-i18next'
import DataTable from '../../components/DataTable'
import EmptyState from '../../components/EmptyState'
import PageHeader from '../../components/PageHeader'
import ActionButtons from '../../components/ActionButtons'
import StatusDot from '../../components/StatusDot'

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

interface Domain {
  id: number
  name: string
  active: boolean
  primary_backend_id?: number | null
  http_to_https: boolean
  hsts_enabled: boolean
  hsts_max_age: number
  hsts_subdomains: boolean
  hsts_preload: boolean
  maintenance_mode: boolean
  maintenance_message?: string | null
  www_redirect: '' | 'to-naked' | 'to-www'
  rate_limit_rps: number
  max_body_kb: number
  disable_h3: boolean
  notes?: string
  created_at: string
  updated_at: string
}

interface DomainFormValues {
  name: string
  active: boolean
  http_to_https: boolean
  hsts_enabled: boolean
  hsts_max_age: number
  hsts_subdomains: boolean
  hsts_preload: boolean
  maintenance_mode: boolean
  maintenance_message?: string
  www_redirect: '' | 'to-naked' | 'to-www'
  rate_limit_rps: number
  max_body_kb: number
  primary_backend_id?: number | null
  notes?: string
}

async function listDomains(): Promise<Domain[]> {
  const r = await apiClient.get('/domains')
  if (!isEnvelope(r.data)) return []
  const payload = r.data.data as { domains?: Domain[] }
  return payload.domains ?? []
}

interface BackendLite {
  id: number
  name: string
  scheme: string
  active: boolean
}
async function listBackends(): Promise<BackendLite[]> {
  const r = await apiClient.get('/backends')
  if (!isEnvelope(r.data)) return []
  return (r.data.data as { backends?: BackendLite[] }).backends ?? []
}

interface TLSCertLite {
  domain: string
  status: 'pending' | 'active' | 'renewing' | 'expired' | 'error'
  not_after?: string | null
}
async function listCerts(): Promise<TLSCertLite[]> {
  const r = await apiClient.get('/tls-certs')
  if (!isEnvelope(r.data)) return []
  return (r.data.data as { tls_certs?: TLSCertLite[] }).tls_certs ?? []
}

interface HAProxyStat { backend: string; server: string; status: string }
// Der Cache-Eintrag ['haproxy','stats'] wird mit dem Dashboard geteilt,
// das aus derselben Antwort zusaetzlich `frontends` liest. Deshalb hier
// IMMER die vollstaendige Antwort cachen und erst per `select` auf die
// Backends reduzieren, die diese Seite braucht.
//
// Befund 2026-09-11: Lieferte diese Funktion nur das Backend-Array, hing
// es vom zuletzt besuchten Screen ab, welche Form unter dem Key lag —
// nach einem Wechsel hierher und zurueck riss das Dashboard mit
// "Cannot read properties of undefined (reading 'length')" die ganze
// Oberflaeche in die ErrorBoundary.
interface HAProxyStatsPayload {
  backends: HAProxyStat[]
  frontends: unknown[]
  error?: string
}
async function fetchHAProxyStats(): Promise<HAProxyStatsPayload> {
  try {
    const r = await apiClient.get('/haproxy/stats')
    if (!isEnvelope(r.data)) return { backends: [], frontends: [] }
    const d = r.data.data as Partial<HAProxyStatsPayload>
    return { backends: d.backends ?? [], frontends: d.frontends ?? [], error: d.error }
  } catch { return { backends: [], frontends: [] } }
}

export default function DomainsPage() {
  const { t } = useTranslation()
  const qc = useQueryClient()
  const navigate = useNavigate()
  const isViewer = useAuthStore((s) => s.user?.role) === 'viewer'

  const { data, isLoading } = useQuery({
    queryKey: ['domains'],
    queryFn: listDomains,
  })
  const { data: backends } = useQuery({ queryKey: ['backends'], queryFn: listBackends })
  // TLS-Certs nebenher laden, damit wir pro Domain den Cert-Status
  // (vorhanden / gültig / ablaufend / fehlt) als Spalte zeigen können.
  // Operator sieht so auf einen Blick welche Domains noch self-signed
  // sind und welche bereits ein gültiges ACME-Cert haben.
  const { data: certs } = useQuery({ queryKey: ['tls-certs'], queryFn: listCerts })
  const { data: haproxyStats } = useQuery({
    queryKey: ['haproxy', 'stats'],
    queryFn: fetchHAProxyStats,
    select: (d: HAProxyStatsPayload) => d.backends,
    refetchInterval: 15_000,
  })
  const certByDomain = new Map((certs ?? []).map(c => [c.domain, c]))
  const backendById = (id?: number | null) => backends?.find(b => b.id === id)

  // Gibt 'UP', 'DOWN' oder null zurück. HAProxy-Backend heißt eg_backend_<id>.
  // Wir aggregieren alle Server: wenn mind. einer UP → UP, sonst DOWN.
  const backendHealth = (id?: number | null): 'UP' | 'DOWN' | null => {
    if (!id || !haproxyStats?.length) return null
    const name = `eg_backend_${id}`
    const servers = haproxyStats.filter(s => s.backend === name)
    if (!servers.length) return null
    return servers.some(s => s.status === 'UP') ? 'UP' : 'DOWN'
  }

  const [creating, setCreating] = useState(false)
  const [quickBackendOpen, setQuickBackendOpen] = useState(false)
  const [form] = Form.useForm<DomainFormValues>()
  const [quickBackendForm] = Form.useForm<{ name: string; scheme: 'http' | 'https'; address: string; port: number }>()

  const quickCreateBackend = useMutation({
    mutationFn: async (v: { name: string; scheme: 'http' | 'https'; address: string; port: number }) => {
      // 1) Backend anlegen
      const bRes = await apiClient.post('/backends', {
        name: v.name, scheme: v.scheme, lb_algorithm: 'roundrobin',
        websocket: false, active: true,
      })
      const bId = (bRes.data?.data as { id?: number })?.id
      if (!bId) throw new Error('backend id missing in response')
      // 2) Ersten Server reinhängen
      await apiClient.post(`/backends/${bId}/servers`, {
        backend_id: bId, name: v.address.replace(/[^a-zA-Z0-9-]/g, '-'),
        address: v.address, port: v.port, weight: 100, active: true,
      })
      return bId
    },
    onSuccess: (bId) => {
      message.success(t('domains.quickBackendCreated'))
      void qc.invalidateQueries({ queryKey: ['backends'] })
      // Frisch erstellten Backend automatisch im Domain-Form selektieren.
      form.setFieldsValue({ primary_backend_id: bId })
      setQuickBackendOpen(false)
      quickBackendForm.resetFields()
    },
    onError: (e: Error) => message.error(t('domains.quickBackendFailed') + ': ' + e.message),
  })

  const create = useMutation({
    mutationFn: async (v: DomainFormValues) => {
      const r = await apiClient.post('/domains', v)
      return r.data
    },
    onSuccess: () => {
      message.success(t('common.save'))
      setCreating(false)
      form.resetFields()
      void qc.invalidateQueries({ queryKey: ['domains'] })
    },
    onError: (e: Error) => message.error(e.message),
  })

  const del = useMutation({
    mutationFn: async (id: number) => {
      await apiClient.delete(`/domains/${id}`)
    },
    onSuccess: () => {
      void qc.invalidateQueries({ queryKey: ['domains'] })
    },
    onError: (e: Error) => message.error(e.message),
  })
  const quickToggle = useMutation({
    mutationFn: async ({ id, row, checked }: { id: number; row: Domain; checked: boolean }) => {
      const { id: _id, created_at: _ca, updated_at: _ua, ...body } = row
      await apiClient.put(`/domains/${id}`, { ...body, active: checked })
    },
    onSuccess: () => { void qc.invalidateQueries({ queryKey: ['domains'] }) },
    onError: (e: Error) => message.error(e.message),
  })

  const columns: ColumnsType<Domain> = [
    {
      title: t('domains.name'), dataIndex: 'name', key: 'name',
      render: (name: string, row: Domain) => (
        <Space size={4} wrap>
          <span>{name}</span>
          {row.maintenance_mode && (
            <Tooltip title={row.maintenance_message || t('domains.maintenanceTag')}>
              <Tag icon={<StopOutlined />} color="orange" style={{ margin: 0 }}>
                {t('domains.maintenanceTag')}
              </Tag>
            </Tooltip>
          )}
          {row.rate_limit_rps > 0 && (
            <Tooltip title={`${row.rate_limit_rps} req/s`}>
              <Tag icon={<ThunderboltOutlined />} color="purple" style={{ margin: 0, fontSize: 11 }}>
                {t('domains.rateLimitTag')}
              </Tag>
            </Tooltip>
          )}
        </Space>
      ),
    },
    {
      title: t('domains.primaryBackend'), dataIndex: 'primary_backend_id', key: 'primary_backend_id',
      render: (id?: number | null) => {
        if (!id) return <Tag>{t('domains.noBackend')}</Tag>
        const b = backendById(id)
        const health = backendHealth(id)
        return (
          <Space size={4}>
            {b
              ? <Tag color="blue">{b.name} ({b.scheme})</Tag>
              : <Tag color="orange">#{id}</Tag>}
            {health === 'UP'   && <Tag color="green"  style={{ margin: 0 }}>UP</Tag>}
            {health === 'DOWN' && <Tag color="red"    style={{ margin: 0 }}>DOWN</Tag>}
          </Space>
        )
      },
    },
    {
      title: t('domains.active'), dataIndex: 'active', key: 'active', width: 80,
      render: (v: boolean, row: Domain) => (
        <Switch
          size="small"
          checked={v}
          disabled={isViewer}
          loading={quickToggle.isPending && quickToggle.variables?.id === row.id}
          onChange={(checked) => quickToggle.mutate({ id: row.id, row, checked })}
        />
      ),
    },
    { title: t('domains.httpToHttps'), dataIndex: 'http_to_https', key: 'http_to_https', render: (v: boolean) => <StatusDot active={v} activeLabel="HTTPS" inactiveLabel="HTTP" /> },
    { title: t('domains.hsts'), dataIndex: 'hsts_enabled', key: 'hsts', render: (v: boolean) => <StatusDot active={v} /> },
    {
      title: t('domains.tlsCert'),
      key: 'tlsCert',
      width: 120,
      render: (_, row) => {
        const cert = certByDomain.get(row.name)
        if (!cert) {
          return (
            <Tooltip title={t('domains.tlsCertNoneHint')}>
              <Tag color="default">{t('domains.tlsCertNone')}</Tag>
            </Tooltip>
          )
        }
        if (cert.status === 'expired') {
          return <Tag color="red">{t('domains.tlsCertExpired')}</Tag>
        }
        if (cert.status === 'error') {
          return <Tag color="red">{t('domains.tlsCertError')}</Tag>
        }
        // Days remaining
        const days = cert.not_after
          ? Math.round((new Date(cert.not_after).getTime() - Date.now()) / 86_400_000)
          : null
        if (days != null && days < 30) {
          return (
            <Tooltip title={cert.not_after}>
              <Tag color="orange">{t('domains.tlsCertExpiring', { days })}</Tag>
            </Tooltip>
          )
        }
        return (
          <Tooltip title={cert.not_after}>
            <Tag color="green">{t('domains.tlsCertValid')}</Tag>
          </Tooltip>
        )
      },
    },
    {
      title: t('common.actions'), key: 'actions',
      render: (_, row) => (
        <ActionButtons
          onEdit={() => navigate(`/domains/${row.id}`)}
          onDelete={() => del.mutate(row.id)}
          deleteConfirm={t('domains.deleteConfirm', { name: row.name })}
        />
      ),
    },
  ]

  // openCreate: reused von extraActions-Button und EmptyState-Action.
  // Setzt die Defaults für die Create-Modal-Form.
  const openCreate = () => {
    setCreating(true); form.resetFields()
    form.setFieldsValue({
      active: true,
      http_to_https: true,
      hsts_enabled: false,
      hsts_max_age: 31536000,
      hsts_subdomains: false,
      hsts_preload: false,
      maintenance_mode: false,
      maintenance_message: '',
      www_redirect: '',
      rate_limit_rps: 0,
      max_body_kb: 0,
    })
  }

  return (
    <div>
      <PageHeader
        icon={<GlobalOutlined />}
        title={t('domains.title')}
        subtitle={t('domains.intro')}
      />
      <DataTable
        rowKey="id"
        loading={isLoading}
        dataSource={data ?? []}
        columns={columns}
        extraActions={
          <Tooltip title={isViewer ? t('auth.viewerBadge') : undefined}>
            <Button type="primary" icon={<PlusOutlined />} onClick={openCreate} disabled={isViewer}>
              {t('domains.addDomain')}
            </Button>
          </Tooltip>
        }
        emptyContent={
          <EmptyState
            icon={<GlobalOutlined />}
            title={t('domains.emptyTitle')}
            description={t('domains.emptyDesc')}
            action={
              <Tooltip title={isViewer ? t('auth.viewerBadge') : undefined}>
                <Button type="primary" icon={<PlusOutlined />} onClick={openCreate} disabled={isViewer}>
                  {t('domains.addDomain')}
                </Button>
              </Tooltip>
            }
          />
        }
      />
      <Modal
        title={t('domains.addDomain')}
        open={creating}
        onCancel={() => setCreating(false)}
        onOk={() => { void form.submit() }}
        confirmLoading={create.isPending}
      >
        <Form form={form} layout="vertical" onFinish={(v) => create.mutate(v)}>
          <Form.Item label={t('domains.name')} name="name" rules={[{ required: true }]}>
            <Input placeholder="example.com" />
          </Form.Item>
          <Form.Item label={t('domains.primaryBackend')} name="primary_backend_id"
            extra={t('domains.primaryBackendHint')}>
            <Space.Compact style={{ width: '100%' }}>
              <Form.Item name="primary_backend_id" noStyle>
                <Select allowClear showSearch optionFilterProp="label"
                  placeholder={t('domains.selectBackend')}
                  options={(backends ?? []).filter(b => b.active).map(b => ({
                    value: b.id, label: b.name,
                  }))}
                  style={{ width: '100%' }}
                />
              </Form.Item>
              <Button onClick={() => setQuickBackendOpen(true)} title={t('domains.quickBackendBtnHint')}>
                {t('domains.quickBackendBtn')}
              </Button>
            </Space.Compact>
          </Form.Item>
          <Form.Item label={t('domains.active')} name="active" valuePropName="checked">
            <Switch />
          </Form.Item>
          <Form.Item label={t('domains.httpToHttps')} name="http_to_https" valuePropName="checked">
            <Switch />
          </Form.Item>
          <Divider plain>
            <Typography.Text type="secondary" style={{ fontSize: 12 }}>
              {t('domains.moreOnDetailPage')}
            </Typography.Text>
          </Divider>
        </Form>
      </Modal>

      {/* Quick-Add-Backend: schmales Sub-Modal direkt aus dem Domain-
          Anlegen-Flow heraus. Spart drei Navigations-Klicks (Backends-
          Seite öffnen → Backend anlegen → Server anlegen → zurück). */}
      <Modal
        title={t('domains.quickBackendTitle')}
        open={quickBackendOpen}
        onCancel={() => { setQuickBackendOpen(false); quickBackendForm.resetFields() }}
        onOk={() => { void quickBackendForm.submit() }}
        confirmLoading={quickCreateBackend.isPending}
        width={520}
      >
        <Form
          form={quickBackendForm}
          layout="vertical"
          initialValues={{ scheme: 'http', port: 80 }}
          onFinish={(v) => quickCreateBackend.mutate(v)}
        >
          <Form.Item label={t('domains.quickBackendName')} name="name" rules={[{ required: true }]}>
            <Input placeholder="app1" />
          </Form.Item>
          <Form.Item label={t('domains.quickBackendScheme')} name="scheme">
            <Select options={[
              { value: 'http', label: 'http' },
              { value: 'https', label: 'https' },
            ]} />
          </Form.Item>
          <Form.Item
            label={t('domains.quickBackendAddress')}
            name="address"
            rules={[
              { required: true },
              { pattern: /^(\d{1,3}\.){3}\d{1,3}$|^[0-9a-fA-F:]{2,39}$|^[a-zA-Z0-9]([a-zA-Z0-9\-.]{0,61}[a-zA-Z0-9])?$/, message: t('backends.server.addressInvalid') },
            ]}
          >
            <Input placeholder="10.0.0.10" />
          </Form.Item>
          <Form.Item label={t('domains.quickBackendPort')} name="port" rules={[{ required: true, type: 'number', min: 1, max: 65535 }]}>
            <InputNumber style={{ width: '100%' }} min={1} max={65535} />
          </Form.Item>
        </Form>
      </Modal>
    </div>
  )
}