import { Alert, Button, Popconfirm, Tooltip, message } from 'antd'
import { CloudDownloadOutlined, ReloadOutlined, RocketOutlined, ClusterOutlined } 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 UpdateBannerProps {
  // compact: rendert nur einen kleinen „Jetzt prüfen"-Button (z. B. im
  // Header), unabhängig davon ob aktuell ein Update verfügbar ist. So
  // hat der Operator immer einen Weg den Server-seitigen Throttle zu
  // umgehen — sonst Catch-22 wenn der Banner mangels Update nicht
  // rendert. Pattern 1:1 aus mail-gateway/Dashboard/v2/UpdateBanner.
  compact?: boolean
}

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

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

interface ClusterStatus {
  mode: string   // "single-node" | "cluster"
  peers: Array<{ id: string; fqdn: string }>
}

interface RollingUpdateState {
  phase: string         // idle | updating-secondary | waiting-secondary | updating-primary | failed
  secondary_fqdn: string
  secondary_id: string
  error?: string
  updated_at: 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({ compact = false }: UpdateBannerProps = {}) {
  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 clusterStatus = useQuery({
    queryKey: ['cluster', 'status-update-banner'],
    queryFn: async () => {
      try {
        const r = await apiClient.get('/cluster/status')
        return isEnvelope(r.data) ? (r.data.data as ClusterStatus) : null
      } catch {
        return null
      }
    },
    refetchInterval: 60_000,
    staleTime: 30_000,
  })

  const rollingStatus = useQuery({
    queryKey: ['cluster', 'rolling-update-status'],
    queryFn: async () => {
      try {
        const r = await apiClient.get('/cluster/rolling-update/status')
        return isEnvelope(r.data) ? (r.data.data as RollingUpdateState) : null
      } catch {
        return null
      }
    },
    refetchInterval: 5_000,
    staleTime: 0,
    gcTime: 0,
  })

  const isCluster = clusterStatus.data?.mode === 'cluster'
  const rollingPhase = rollingStatus.data?.phase ?? 'idle'
  const rollingActive = rollingPhase !== 'idle' && rollingPhase !== 'failed' && rollingPhase !== 'done'
  const secondaryFQDN = rollingStatus.data?.secondary_fqdn ?? ''

  // Verhindert dass ein stale "done" aus einer vorherigen Session sofort
  // einen Reload auslöst. Nur wenn rollingActive in DIESER Session true
  // war, reagieren wir auf "done".
  const wasRollingActiveRef = useRef(false)

  // Normal single-node upgrade state
  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>('')

  // Rolling update elapsed counter
  const [rollingElapsed, setRollingElapsed] = useState(0)
  const rollingTickRef = useRef<ReturnType<typeof setInterval> | null>(null)

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

  // Start rolling elapsed timer when rolling becomes active
  useEffect(() => {
    if (rollingActive) {
      wasRollingActiveRef.current = true
      if (!rollingTickRef.current) {
        setRollingElapsed(0)
        rollingTickRef.current = setInterval(() => setRollingElapsed(e => e + 1), 1000)
      }
    } else if (!rollingActive && rollingTickRef.current) {
      clearInterval(rollingTickRef.current)
      rollingTickRef.current = null
    }
  }, [rollingActive])

  // "done": nur reagieren wenn wir in DIESER Session rollingActive gesehen
  // haben — sonst würde ein stale "done" sofort einen Reload auslösen.
  useEffect(() => {
    if (rollingPhase === 'done' && wasRollingActiveRef.current) {
      msg.success(t('update.success', { version: targetRef.current || '…' }))
      setTimeout(() => window.location.reload(), 1500)
    }
  }, [rollingPhase, msg, t])

  // Fallback: wenn "updating-primary" und die API noch antwortet (Primary
  // schon neu gestartet bevor das UI die Phase gesehen hat), poll auf "done".
  useEffect(() => {
    if (rollingPhase === 'updating-primary') {
      let sawDown = false
      const poll = setInterval(async () => {
        try {
          const res = await apiClient.get('/system/health')
          const newV = isEnvelope(res.data) ? (res.data.data as SystemHealth).version : ''
          if (sawDown && newV) {
            clearInterval(poll)
            void rollingStatus.refetch()
          }
        } catch {
          sawDown = true
        }
      }, 3000)
      // Safety: nach 2 Min einfach reload
      const safety = setTimeout(() => { clearInterval(poll); window.location.reload() }, 120_000)
      return () => { clearInterval(poll); clearTimeout(safety) }
    }
  }, [rollingPhase, rollingStatus])

  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 {
      const r = await apiClient.get('/system/package-versions?force=1')
      const fresh = (isEnvelope(r.data) ? (r.data.data as PackageVersions) : {})
      void pkgVersions.refetch()
      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(() => {
        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 {
            sawDown = true
          }
        }, 3000)
        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)
      })
  }

  const startRollingUpdate = () => {
    installedRef.current = installedVersion
    targetRef.current = targetVersion
    apiClient.post('/cluster/rolling-update')
      .then(() => {
        void rollingStatus.refetch()
      })
      .catch((e: Error) => {
        msg.error(t('update.failed') + ': ' + e.message)
      })
  }

  if (compact) {
    if (updateAvailable) {
      return <>{msgCtx}</>
    }
    return (
      <>
        {msgCtx}
        <Tooltip title={t('update.checkNowHint')}>
          <Button
            type="default"
            icon={<ReloadOutlined />}
            loading={forceChecking}
            onClick={forceCheck}
          >
            {t('update.checkNow')}
          </Button>
        </Tooltip>
      </>
    )
  }

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

  return (
    <>
      {msgCtx}

      {updateAvailable && !upgrading && !rollingActive && (
        <Alert
          type="warning"
          banner
          showIcon
          icon={<CloudDownloadOutlined />}
          message={
            <div className="update-banner-row">
              <span>{t('update.available', { version: targetVersion })}</span>
              {isCluster ? (
                <Popconfirm
                  title={t('update.rollingConfirmTitle')}
                  description={t('update.rollingConfirmDesc', {
                    secondary: clusterStatus.data?.peers?.[0]?.fqdn ?? 'secondary',
                  })}
                  okText={t('update.rollingUpdate')}
                  cancelText={t('common.cancel')}
                  onConfirm={startRollingUpdate}
                >
                  <Button size="small" type="primary" icon={<ClusterOutlined />}>
                    Rolling Update
                  </Button>
                </Popconfirm>
              ) : (
                <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>
              )}
            </div>
          }
        />
      )}

      {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>
      )}

      {rollingActive && (
        <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">
                <ClusterOutlined className="update-modal__icon" />
              </div>
            </div>

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

            <div className="update-modal__steps">
              <Step
                done={rollingPhase === 'waiting-secondary' || rollingPhase === 'updating-primary'}
                active={rollingPhase === 'updating-secondary'}
                label={t('update.rollingStepSecondary', { fqdn: secondaryFQDN })}
              />
              <Step
                done={rollingPhase === 'updating-primary'}
                active={rollingPhase === 'waiting-secondary'}
                label={t('update.rollingStepWaiting')}
              />
              <Step
                done={false}
                active={rollingPhase === 'updating-primary'}
                label={t('update.rollingStepPrimary')}
              />
            </div>

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

            {rollingStatus.data?.error && (
              <div className="update-modal__hint" style={{ color: '#ff4d4f' }}>
                {rollingStatus.data.error}
              </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>
  )
}