import { useEffect, useRef, useState } from 'react'
import {
  Alert, Button, Card, Col, Popconfirm, Row, Space, Statistic, Table, Tag, Tooltip, Typography, message,
} from 'antd'
import type { ColumnsType } from 'antd/es/table'
import {
  CloudDownloadOutlined,
  CloudUploadOutlined,
  DeleteOutlined,
  ReloadOutlined,
  RocketOutlined,
  UndoOutlined,
} from '@ant-design/icons'
import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
import { useTranslation } from 'react-i18next'
import dayjs from 'dayjs'

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

const { Text } = Typography

interface Backup {
  id: number
  file: string
  size_bytes: number
  sha256: string
  db_dump_bytes: number
  files_bytes: number
  kind: 'manual' | 'scheduled'
  status: 'success' | 'failed'
  error?: string
  host?: string
  started_at: string
  finished_at: string
}

function fmtSize(n: number): string {
  if (n < 1024) return n + ' B'
  if (n < 1024 * 1024) return (n / 1024).toFixed(1) + ' KB'
  if (n < 1024 * 1024 * 1024) return (n / 1024 / 1024).toFixed(1) + ' MB'
  return (n / 1024 / 1024 / 1024).toFixed(2) + ' GB'
}

function fmtDuration(start: string, end: string): string {
  const ms = new Date(end).getTime() - new Date(start).getTime()
  if (ms < 1000) return ms + ' ms'
  if (ms < 60_000) return (ms / 1000).toFixed(1) + ' s'
  return (ms / 60_000).toFixed(1) + ' min'
}

export default function HistoryTab() {
  const { t } = useTranslation()
  const qc = useQueryClient()
  const isViewer = useAuthStore((s) => s.user?.role) === 'viewer'
  const [msg, msgCtx] = message.useMessage()

  const list = useQuery({
    queryKey: ['backups'],
    queryFn: async () => {
      const r = await apiClient.get('/backups')
      return isEnvelope(r.data) ? (r.data.data as { backups: Backup[] }).backups : []
    },
    refetchInterval: 30_000,
  })

  const trigger = useMutation({
    mutationFn: async () => {
      const r = await apiClient.post('/backups')
      return isEnvelope(r.data) ? r.data.data : r.data
    },
    onSuccess: (res: { file?: string }) => {
      msg.success(t('backups.created', { file: res?.file ?? '?' }))
      qc.invalidateQueries({ queryKey: ['backups'] })
    },
    onError: (e: Error) => msg.error(t('backups.failed') + ': ' + e.message),
  })

  const [busyDelete, setBusyDelete] = useState<number | null>(null)
  const del = useMutation({
    mutationFn: async (id: number) => {
      setBusyDelete(id)
      try { await apiClient.delete(`/backups/${id}`) } finally { setBusyDelete(null) }
    },
    onSuccess: () => {
      msg.success(t('backups.deleted'))
      qc.invalidateQueries({ queryKey: ['backups'] })
    },
    onError: (e: Error) => msg.error(e.message),
  })

  // Restore-Modal-State: nach Klick aufs Restore zeigen wir ein
  // Vollbild-Overlay mit Step-Indicator + Health-Poll (analog Update).
  const [restoring, setRestoring] = useState<{ file: string } | null>(null)
  const [restoreElapsed, setRestoreElapsed] = useState(0)
  const tickRef = useRef<ReturnType<typeof setInterval> | null>(null)
  const pollRef = useRef<ReturnType<typeof setInterval> | null>(null)

  useEffect(() => () => {
    if (tickRef.current) clearInterval(tickRef.current)
    if (pollRef.current) clearInterval(pollRef.current)
  }, [])

  const restore = useMutation({
    mutationFn: async (id: number) => {
      const r = await apiClient.post(`/backups/${id}/restore`)
      return isEnvelope(r.data) ? r.data.data : r.data
    },
    onError: (e: Error) => {
      setRestoring(null)
      if (tickRef.current) clearInterval(tickRef.current)
      msg.error(t('backups.restoreFailed') + ': ' + e.message)
    },
  })

  const startRestore = (b: Backup) => {
    setRestoring({ file: b.file })
    setRestoreElapsed(0)
    tickRef.current = setInterval(() => setRestoreElapsed((e) => e + 1), 1000)
    restore.mutate(b.id, {
      onSuccess: () => {
        // Poll /system/health bis API neu hochkommt → reload.
        let sawDown = false
        pollRef.current = setInterval(async () => {
          try {
            const res = await apiClient.get('/system/health')
            const v = isEnvelope(res.data) ? (res.data.data as { version: string }).version : ''
            if (sawDown && v) {
              if (pollRef.current) clearInterval(pollRef.current)
              if (tickRef.current) clearInterval(tickRef.current)
              setRestoring(null)
              msg.success(t('backups.restoreDone'))
              setTimeout(() => window.location.reload(), 1500)
            }
          } catch {
            sawDown = true
          }
        }, 3000)
        // Safety-Timeout 3 min — Restore kann bei großer DB länger
        // dauern als Upgrade. Danach reload trotzdem.
        setTimeout(() => {
          if (pollRef.current) clearInterval(pollRef.current)
          if (tickRef.current) clearInterval(tickRef.current)
          setRestoring(null)
          window.location.reload()
        }, 180_000)
      },
    })
  }

  const download = (b: Backup) => {
    // gin.FileAttachment liefert via Browser direkt; einfach
    // Cookie-authentifiziert in eine versteckte Form öffnen.
    const url = `/api/v1/backups/${b.id}/download`
    const a = document.createElement('a')
    a.href = url
    a.download = b.file
    document.body.appendChild(a)
    a.click()
    document.body.removeChild(a)
  }

  const columns: ColumnsType<Backup> = [
    {
      title: t('backups.col.time'), dataIndex: 'started_at', width: 170,
      render: (v: string) => <Text style={{ fontFamily: 'monospace', fontSize: 12 }}>
        {dayjs(v).format('YYYY-MM-DD HH:mm:ss')}
      </Text>,
    },
    {
      title: t('backups.col.file'), dataIndex: 'file',
      render: (v: string, row) => (
        <div>
          <Text style={{ fontFamily: 'monospace' }}>{v}</Text>
          <div>
            <Text type="secondary" style={{ fontSize: 11 }}>
              sha256: {row.sha256.slice(0, 16)}…
            </Text>
          </div>
        </div>
      ),
    },
    {
      title: t('backups.col.kind'), dataIndex: 'kind', width: 110,
      render: (k: Backup['kind']) =>
        <Tag color={k === 'scheduled' ? 'cyan' : 'blue'}>{k}</Tag>,
    },
    {
      title: t('backups.col.status'), dataIndex: 'status', width: 110,
      render: (s: Backup['status'], row) =>
        s === 'success'
          ? <Tag color="green">{t('backups.okTag')}</Tag>
          : (
            <Tooltip title={row.error}>
              <Tag color="red">{t('backups.failedTag')}</Tag>
            </Tooltip>
          ),
    },
    {
      title: t('backups.col.size'), dataIndex: 'size_bytes', width: 110,
      render: (n: number, row) => (
        <div>
          <Text>{fmtSize(n)}</Text>
          <div>
            <Text type="secondary" style={{ fontSize: 11 }}>
              DB {fmtSize(row.db_dump_bytes)} · Files {fmtSize(row.files_bytes)}
            </Text>
          </div>
        </div>
      ),
    },
    {
      title: t('backups.col.duration'), key: 'duration', width: 90,
      render: (_, row) => <Text type="secondary">{fmtDuration(row.started_at, row.finished_at)}</Text>,
    },
    {
      title: t('common.actions'), key: 'a', width: 280,
      render: (_, row) => (
        <Space size={4}>
          <Tooltip title={t('backups.downloadTooltip')}>
            <Button
              size="small"
              icon={<CloudDownloadOutlined />}
              onClick={() => download(row)}
              disabled={row.status !== 'success'}
            >{t('backups.download')}</Button>
          </Tooltip>
          {isViewer
            ? <Tooltip title={t('auth.viewerBadge')}><Button size="small" icon={<UndoOutlined />} disabled>{t('backups.restore')}</Button></Tooltip>
            : <Popconfirm
                title={t('backups.confirmRestoreTitle')}
                description={t('backups.confirmRestoreDesc', { file: row.file })}
                okText={t('backups.restoreOk')}
                okButtonProps={{ danger: true }}
                cancelText={t('common.cancel')}
                onConfirm={() => startRestore(row)}
                disabled={row.status !== 'success'}
              >
                <Button size="small" icon={<UndoOutlined />} disabled={row.status !== 'success'}>{t('backups.restore')}</Button>
              </Popconfirm>
          }
          {isViewer
            ? <Tooltip title={t('auth.viewerBadge')}><Button size="small" danger icon={<DeleteOutlined />} disabled>{t('common.delete')}</Button></Tooltip>
            : <Popconfirm
                title={t('backups.confirmDelete', { file: row.file })}
                onConfirm={() => del.mutate(row.id)}
                okButtonProps={{ danger: true }}
              >
                <Button size="small" danger icon={<DeleteOutlined />} loading={busyDelete === row.id}>{t('common.delete')}</Button>
              </Popconfirm>
          }
        </Space>
      ),
    },
  ]

  // Aggregat-Zähler. Quelle: die bereits geladene Liste — die Backup-
  // History wird in der UI sowieso komplett geladen (Pagination ist
  // clientseitig). Keine zusätzlichen Endpoint-Calls.
  const all = list.data ?? []
  const succ = all.filter((b) => b.status === 'success')
  const lastSucc = succ[0] // bereits DESC sortiert vom Backend
  const totalSize = succ.reduce((acc, b) => acc + (b.size_bytes || 0), 0)
  const last24hMs = Date.now() - 86_400_000
  const failsLast24h = all.filter((b) =>
    b.status === 'failed' && new Date(b.started_at).getTime() >= last24hMs,
  ).length
  const lastSuccAge = lastSucc
    ? Math.round((Date.now() - new Date(lastSucc.finished_at).getTime()) / 3_600_000) // hours
    : null

  return (
    <div>
      {msgCtx}

      {all.length > 0 && (
        <Row gutter={12} className="mb-16">
          <Col xs={12} sm={6}>
            <Card size="small">
              <Statistic
                title={t('backups.statLastSuccess')}
                value={
                  lastSuccAge == null
                    ? '—'
                    : lastSuccAge < 24
                      ? t('backups.statHoursAgo', { n: lastSuccAge })
                      : t('backups.statDaysAgo', { n: Math.round(lastSuccAge / 24) })
                }
                valueStyle={
                  lastSuccAge == null ? { color: '#cf1322' }
                    : lastSuccAge > 48 ? { color: '#d48806' }
                    : { color: '#0F172A' }
                }
              />
            </Card>
          </Col>
          <Col xs={12} sm={6}>
            <Card size="small">
              <Statistic title={t('backups.statTotal')} value={succ.length} />
            </Card>
          </Col>
          <Col xs={12} sm={6}>
            <Card size="small">
              <Statistic title={t('backups.statSize')} value={fmtSize(totalSize)} />
            </Card>
          </Col>
          <Col xs={12} sm={6}>
            <Card size="small">
              <Statistic
                title={t('backups.statFails24h')}
                value={failsLast24h}
                valueStyle={failsLast24h > 0 ? { color: '#cf1322' } : undefined}
              />
            </Card>
          </Col>
        </Row>
      )}

      <Space style={{ marginBottom: 12 }}>
        <Tooltip title={t('backups.refreshTooltip')}>
          <Button icon={<ReloadOutlined />} onClick={() => list.refetch()}>
            {t('common.refresh')}
          </Button>
        </Tooltip>
        <Tooltip title={isViewer ? t('auth.viewerBadge') : undefined}>
          <Button
            type="primary"
            icon={<CloudUploadOutlined />}
            loading={trigger.isPending}
            disabled={isViewer}
            onClick={() => trigger.mutate()}
          >
            {t('backups.runNow')}
          </Button>
        </Tooltip>
      </Space>

      <Card className="mb-16">
        <Alert
          type="info"
          showIcon
          message={t('backups.scopeTitle')}
          description={t('backups.scopeDesc')}
        />
      </Card>

      <Table
        rowKey="id"
        size="small"
        loading={list.isFetching}
        dataSource={list.data ?? []}
        columns={columns}
        pagination={{ defaultPageSize: 25, showSizeChanger: true, pageSizeOptions: [25, 50, 100] }}
        locale={{ emptyText: t('backups.empty') }}
      />

      {restoring && (
        <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('backups.restoreRunning')}</div>
            <div className="update-modal__version">{restoring.file}</div>
            <div className="update-modal__steps">
              <div className={`update-modal__step ${restoreElapsed < 5 ? 'update-modal__step--active' : 'update-modal__step--done'}`}>
                <span className="update-modal__step-dot" />
                <span>{t('backups.step.extract')}</span>
              </div>
              <div className={`update-modal__step ${restoreElapsed >= 5 && restoreElapsed < 15 ? 'update-modal__step--active' : restoreElapsed >= 15 ? 'update-modal__step--done' : ''}`}>
                <span className="update-modal__step-dot" />
                <span>{t('backups.step.psql')}</span>
              </div>
              <div className={`update-modal__step ${restoreElapsed >= 15 && restoreElapsed < 25 ? 'update-modal__step--active' : restoreElapsed >= 25 ? 'update-modal__step--done' : ''}`}>
                <span className="update-modal__step-dot" />
                <span>{t('backups.step.render')}</span>
              </div>
              <div className={`update-modal__step ${restoreElapsed >= 25 ? 'update-modal__step--active' : ''}`}>
                <span className="update-modal__step-dot" />
                <span>{t('backups.step.restart')}</span>
              </div>
            </div>
            <div className="update-modal__timer">{restoreElapsed}s</div>
            <div className="update-modal__hint">{t('backups.restoreHint')}</div>
          </div>
        </div>
      )}
    </div>
  )
}