import { Alert, Button, Popconfirm, Space, message } from 'antd'
import { CloudDownloadOutlined, ReloadOutlined, RocketOutlined } from '@ant-design/icons'
import { useQuery } from '@tanstack/react-query'
import { useEffect, useRef, useState } from 'react'
import { useTranslation } from 'react-i18next'

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

interface PackageVersions { [key: string]: string }
interface SystemHealth { status: string; version: string }

interface PendingUpdate { pkg: string; installed: string; available: string }

// allUpdates parsed das flache map-Format ({pkg_installed,pkg_available})
// das /system/package-versions zurückliefert. Eines davon ist meist
// das meta-Paket "edgeguard" → die "Ziel-Version".
function allUpdates(v: PackageVersions): PendingUpdate[] {
  const out: PendingUpdate[] = []
  for (const key of Object.keys(v)) {
    if (!key.endsWith('_installed')) continue
    const pkg = key.replace('_installed', '')
    const installed = v[key]
    const available = v[`${pkg}_available`]
    if (installed && available && installed !== available) {
      out.push({ pkg, installed, available })
    }
  }
  return out
}

export default function UpdateBanner() {
  const { t } = useTranslation()
  const [msg, msgCtx] = message.useMessage()

  const pkgVersions = useQuery({
    queryKey: ['system', 'package-versions'],
    queryFn: async () => {
      const r = await apiClient.get('/system/package-versions')
      return isEnvelope(r.data) ? (r.data.data as PackageVersions) : ({} as PackageVersions)
    },
    refetchInterval: 30_000,
    refetchOnMount: 'always',
    staleTime: 0,
    gcTime: 0,
  })

  const [upgrading, setUpgrading] = useState(false)
  const [upgradeElapsed, setUpgradeElapsed] = useState(0)
  const [forceChecking, setForceChecking] = useState(false)
  const upgradePollRef = useRef<ReturnType<typeof setInterval> | null>(null)
  const upgradeTickRef = useRef<ReturnType<typeof setInterval> | null>(null)
  const installedRef = useRef<string>('')
  const targetRef = useRef<string>('')

  useEffect(() => () => {
    if (upgradePollRef.current) clearInterval(upgradePollRef.current)
    if (upgradeTickRef.current) clearInterval(upgradeTickRef.current)
  }, [])

  const data = pkgVersions.data ?? {}
  const updates = allUpdates(data)
  const updateAvailable = updates.length > 0
  const meta = updates.find(u => u.pkg === 'edgeguard') ?? updates[0]
  const installedVersion = meta?.installed ?? ''
  const targetVersion = meta?.available ?? ''

  const forceCheck = async () => {
    setForceChecking(true)
    try {
      await pkgVersions.refetch()
      const fresh = pkgVersions.data ?? {}
      const found = allUpdates(fresh).length > 0
      msg[found ? 'success' : 'info'](
        found ? t('update.checkDone') : t('update.noUpdate'),
      )
    } catch {
      msg.error(t('update.checkFailed'))
    } finally {
      setForceChecking(false)
    }
  }

  const startUpgrade = () => {
    installedRef.current = installedVersion
    targetRef.current = targetVersion
    setUpgrading(true)
    setUpgradeElapsed(0)
    upgradeTickRef.current = setInterval(() => setUpgradeElapsed((e) => e + 1), 1000)

    apiClient.post('/system/upgrade')
      .then(() => {
        // Poll /healthz (kein Auth, robust auch wenn die API gerade
        // restartet und Cookie ihre Session nicht erkennt).
        let sawDown = false
        upgradePollRef.current = setInterval(async () => {
          try {
            const res = await apiClient.get('/system/health')
            const newV = (isEnvelope(res.data) ? (res.data.data as SystemHealth).version : '')
            const flipped = newV && installedRef.current && newV !== installedRef.current
            if (flipped || sawDown) {
              if (upgradePollRef.current) clearInterval(upgradePollRef.current)
              if (upgradeTickRef.current) clearInterval(upgradeTickRef.current)
              setUpgrading(false)
              msg.success(t('update.success', { version: targetRef.current }))
              setTimeout(() => window.location.reload(), 1500)
            }
          } catch {
            // Connection refused / 502 → API restartet. Beim nächsten
            // erfolgreichen Poll erkennen wir den Version-Flip.
            sawDown = true
          }
        }, 3000)
        // Sicherheits-Timeout: nach 2 Min einfach reload — falls der
        // Restart länger braucht als erwartet, kommt die UI in jedem
        // Fall wieder hoch.
        setTimeout(() => {
          if (upgradePollRef.current) clearInterval(upgradePollRef.current)
          if (upgradeTickRef.current) clearInterval(upgradeTickRef.current)
          setUpgrading(false)
          window.location.reload()
        }, 120_000)
      })
      .catch((e: Error) => {
        if (upgradeTickRef.current) clearInterval(upgradeTickRef.current)
        if (upgradePollRef.current) clearInterval(upgradePollRef.current)
        setUpgrading(false)
        msg.error(t('update.failed') + ': ' + e.message)
      })
  }

  if (!updateAvailable && !upgrading) {
    return <>{msgCtx}</>
  }

  return (
    <>
      {msgCtx}

      {updateAvailable && !upgrading && (
        <Alert
          type="warning"
          banner
          showIcon
          icon={<CloudDownloadOutlined />}
          message={t('update.available', { version: targetVersion })}
          description={updates.length > 1
            ? t('update.multiPackageHint', { count: updates.length })
            : undefined}
          action={
            <Space>
              <Button
                size="small"
                icon={<ReloadOutlined />}
                loading={forceChecking}
                onClick={forceCheck}
              >
                {t('update.checkNow')}
              </Button>
              <Popconfirm
                title={t('update.confirmTitle')}
                description={t('update.confirmDesc', { version: targetVersion })}
                okText={t('update.applyNow')}
                cancelText={t('common.cancel')}
                onConfirm={startUpgrade}
              >
                <Button size="small" type="primary" icon={<CloudDownloadOutlined />}>
                  {t('update.applyNow')}
                </Button>
              </Popconfirm>
            </Space>
          }
        />
      )}

      {upgrading && (
        <div className="update-modal-overlay">
          <div className="update-modal">
            <div className="update-modal__orbit">
              <div className="update-modal__ring" />
              <div className="update-modal__ring update-modal__ring--2" />
              <div className="update-modal__dot" />
              <div className="update-modal__dot update-modal__dot--2" />
              <div className="update-modal__center">
                <RocketOutlined className="update-modal__icon" />
              </div>
            </div>

            <div className="update-modal__title">{t('update.running')}</div>
            <div className="update-modal__version">
              v{installedRef.current || '…'} → v{targetRef.current || '…'}
            </div>

            <div className="update-modal__steps">
              <Step
                done={upgradeElapsed >= 5}
                active={upgradeElapsed < 5}
                label={t('update.stepDownload')}
              />
              <Step
                done={upgradeElapsed >= 15}
                active={upgradeElapsed >= 5 && upgradeElapsed < 15}
                label={t('update.stepInstall')}
              />
              <Step
                done={upgradeElapsed >= 25}
                active={upgradeElapsed >= 15 && upgradeElapsed < 25}
                label={t('update.stepRestart')}
              />
              <Step
                done={false}
                active={upgradeElapsed >= 25}
                label={t('update.stepVerify')}
              />
            </div>

            <div className="update-modal__timer">{upgradeElapsed}s</div>
            <div className="update-modal__hint">{t('update.waitHint')}</div>
          </div>
        </div>
      )}
    </>
  )
}

function Step({ done, active, label }: { done: boolean; active: boolean; label: string }) {
  const cls =
    'update-modal__step' +
    (active ? ' update-modal__step--active' : '') +
    (done ? ' update-modal__step--done' : '')
  return (
    <div className={cls}>
      <span className="update-modal__step-dot" />
      <span>{label}</span>
    </div>
  )
}