"use client"

import { Suspense, useEffect, useMemo, useRef, useState } from "react"
import Link from "next/link"
import { can } from "@/lib/auth"
import { useSearchParams } from "next/navigation"
import { serverCreateSchema } from "@mmapp/contracts/servers"
import { OperationGate, pollServers, serverOperationError, type PollResult } from "@/lib/server-operations"
import { Alert, AlertTitle, AlertDescription } from "@/components/reui/alert"
import { AlertDialog, AlertDialogContent, AlertDialogHeader, AlertDialogTitle, AlertDialogDescription, AlertDialogFooter } from "@/components/ui/alert-dialog"
import { PageHeader } from "@/components/page-header"
import { FormField, FormToggle, SectionTitle, SegmentedControl } from "@/components/form-kit"
import { DataPageToolbar } from "@/components/data-page-toolbar"
import { ServersDataGrid } from "@/components/data-grids/servers-data-grid"
import { useServerUrlState } from "@/hooks/use-server-url-state"
import { ServerFilters } from "@/components/data-grids/server-filters"
import { applyFilterQuery } from "@/lib/data-filters/apply-filter-query"
import { SERVER_FILTER_ACCESSORS } from "@/lib/data-filters/server-filter-fields"
import { servers as initialServers } from "@/lib/data"
import type { ServerType, Server, WanUplink } from "@/lib/data"
import type { ServerCreate, ServerUpdate } from "@mmapp/contracts/servers"
import { toFrontendServer } from "@/entities/server/model/mappers"
import {
  createServer,
  deleteServer,
  getServer,
  listServers,
  pollServer,
  testServerConnection,
  updateServer,
} from "@/shared/api/servers"

// ─── Backend integration ──────────────────────────────────────────────────────

import { useDataSource } from "@/lib/data-source"
import { Flag } from "@/components/flag"
import { cn } from "@/lib/utils"
import { KpiStatGrid } from "@/components/reui-kit/kpi-stat-grid"
import { DataPageCard } from "@/components/data-page-card"
import { Button } from "@/components/ui/button"
import { Input } from "@/components/ui/input"
import {
  Sheet, SheetContent, SheetHeader, SheetTitle,
  SheetDescription, SheetFooter, SheetClose,
} from "@/components/ui/sheet"
import {
  Stepper,
  StepperContent,
  StepperIndicator,
  StepperItem,
  StepperNav,
  StepperPanel,
  StepperSeparator,
  StepperTitle,
  StepperTrigger,
} from "@/components/reui-kit/accessible-stepper"
import {
  RefreshCwIcon, PlusIcon, TrashIcon,
  EyeIcon, EyeOffIcon,
  ChevronRightIcon, ChevronDownIcon,
  CheckCircleIcon, XCircleIcon, LoaderCircleIcon,
  ShieldIcon, WifiIcon,
  HomeIcon, ServerIcon, NetworkIcon,
} from "lucide-react"

// ─── Countries ───────────────────────────────────────────────────────────────

const COUNTRIES = [
  { code: "RU", label: "Россия" }, { code: "DE", label: "Германия" },
  { code: "NL", label: "Нидерланды" }, { code: "SG", label: "Сингапур" },
  { code: "FI", label: "Финляндия" }, { code: "SE", label: "Швеция" },
  { code: "FR", label: "Франция" }, { code: "GB", label: "Великобритания" },
  { code: "PL", label: "Польша" }, { code: "US", label: "США" },
  { code: "UA", label: "Украина" }, { code: "TR", label: "Турция" },
  { code: "JP", label: "Япония" }, { code: "HK", label: "Гонконг" },
  { code: "KZ", label: "Казахстан" }, { code: "BY", label: "Беларусь" },
  { code: "LT", label: "Литва" }, { code: "LV", label: "Латвия" },
  { code: "EE", label: "Эстония" }, { code: "CZ", label: "Чехия" },
  { code: "AT", label: "Австрия" }, { code: "CH", label: "Швейцария" },
  { code: "NO", label: "Норвегия" },
]

// ─── Shared small components ──────────────────────────────────────────────────

// ─── Country field ────────────────────────────────────────────────────────────

function CountryField({ value, onChange }: { value: string; onChange: (v: string) => void }) {
  const [query, setQuery] = useState("")
  const q = query.trim().toUpperCase()
  const visible = q.length === 0
    ? COUNTRIES
    : COUNTRIES.filter(c => c.code.startsWith(q) || c.label.toLowerCase().includes(query.trim().toLowerCase()))

  return (
    <div className="flex flex-col gap-2">
      <label className="text-sm font-medium">Страна <span className="text-destructive">*</span></label>
      <div className="flex items-center gap-2">
        <div className="relative flex-1">
          <Input placeholder="Поиск или код (RU, DE…)" value={query}
            onChange={e => {
              const v = e.target.value.toUpperCase().slice(0, 3)
              setQuery(v)
              if (v.length === 2) {
                const match = COUNTRIES.find(c => c.code === v)
                if (match) onChange(match.code)
              }
            }}
            className="font-mono pr-10 h-8 text-sm" />
          {value && (
            <span className="absolute right-2.5 top-1/2 -translate-y-1/2">
              <Flag code={value} size={20} />
            </span>
          )}
        </div>
        {value && (
          <span className="text-sm font-mono text-muted-foreground shrink-0">
            {COUNTRIES.find(c => c.code === value)?.label ?? value}
          </span>
        )}
      </div>
      <div className="grid grid-cols-5 gap-1.5 max-h-52 overflow-y-auto pr-0.5">
        {visible.map(c => (
          <button key={c.code} type="button"
            onClick={() => { onChange(c.code); setQuery("") }}
            title={`${c.code} · ${c.label}`}
            className={cn(
              "flex flex-col items-center gap-1 px-1 py-2 rounded-lg border text-[10px] transition-all",
              value === c.code
                ? "border-primary bg-primary/5 ring-1 ring-primary/30 font-semibold text-primary"
                : "border-border hover:border-muted-foreground/40 hover:bg-muted/40 text-muted-foreground",
            )}>
            <Flag code={c.code} size={24} />
            <span className="font-mono leading-none">{c.code}</span>
          </button>
        ))}
      </div>
    </div>
  )
}

// ─── WAN uplinks editor ───────────────────────────────────────────────────────

function newWan(): WanUplink {
  return { id: `w${Date.now()}`, name: "", isp: "", iface: "ether1", ip: "", maxDl: 100, maxUl: 100 }
}

function WanUplinkEditor({ wans, onChange }: {
  wans: WanUplink[]
  onChange: (wans: WanUplink[]) => void
}) {
  function updateWan(id: string, patch: Partial<WanUplink>) {
    onChange(wans.map(w => w.id === id ? { ...w, ...patch } : w))
  }
  function removeWan(id: string) { onChange(wans.filter(w => w.id !== id)) }
  function addWan() { onChange([...wans, newWan()]) }

  return (
    <div className="flex flex-col gap-3">
      {wans.map((wan, idx) => (
        <div key={wan.id} className="rounded-lg border border-border bg-muted/20 p-3 flex flex-col gap-3">
          <div className="flex items-center justify-between">
            <span className="text-xs font-semibold text-muted-foreground uppercase tracking-wide">
              WAN {idx + 1}
            </span>
            <button type="button" onClick={() => removeWan(wan.id)}
              className="text-muted-foreground hover:text-destructive transition-colors">
              <TrashIcon className="size-3.5" />
            </button>
          </div>
          <div className="grid grid-cols-2 gap-2">
            <FormField label="Имя" required>
              <Input className="h-8 font-mono text-xs" placeholder="WAN1-RT"
                value={wan.name} onChange={e => updateWan(wan.id, { name: e.target.value })} />
            </FormField>
            <FormField label="Интерфейс">
              <Input className="h-8 font-mono text-xs" placeholder="ether1"
                value={wan.iface} onChange={e => updateWan(wan.id, { iface: e.target.value })} />
            </FormField>
            <FormField label="Провайдер (ISP)">
              <Input className="h-8 text-xs" placeholder="Rostelecom"
                value={wan.isp} onChange={e => updateWan(wan.id, { isp: e.target.value })} />
            </FormField>
            <FormField label="Внешний IP">
              <Input className="h-8 font-mono text-xs" placeholder="94.25.168.1"
                value={wan.ip} onChange={e => updateWan(wan.id, { ip: e.target.value })} />
            </FormField>
            <FormField label="↓ Макс. Мбит">
              <Input className="h-8 font-mono text-xs" type="number" min={1}
                value={wan.maxDl} onChange={e => updateWan(wan.id, { maxDl: Number(e.target.value) })} />
            </FormField>
            <FormField label="↑ Макс. Мбит">
              <Input className="h-8 font-mono text-xs" type="number" min={1}
                value={wan.maxUl} onChange={e => updateWan(wan.id, { maxUl: Number(e.target.value) })} />
            </FormField>
          </div>
        </div>
      ))}
      <Button type="button" variant="outline" size="sm" className="w-fit gap-1.5" onClick={addWan}>
        <PlusIcon className="size-3.5" />Добавить WAN-аплинк
      </Button>
    </div>
  )
}

// ─── Form state ───────────────────────────────────────────────────────────────

const defaultForm = {
  name: "", type: "exit-node" as ServerType, site: "", country: "RU", asn: "", enabled: true,
  host: "", port: "443", proto: "https" as "http" | "https",
  verifySsl: true, timeout: 10,
  apiPath: "/rest", username: "", password: "", showPassword: false,
  showAdvanced: false, sshPort: 22, winboxPort: 8291, comment: "",
  // home-router extras
  lanSubnet: "",
  wanUplinks: [] as WanUplink[],
}

type FormState = typeof defaultForm
type TestState = "idle" | "testing" | "ok" | "error"
type TypeFilter = "all" | ServerType
type SheetMode = "add" | "edit"

// ════════════════════════════════════════════════════════════════════════════
function ServersPageContent() {
  const searchParams = useSearchParams()
  const selectedServerId = searchParams.get("server")
  const clearParams = new URLSearchParams(searchParams.toString())
  clearParams.delete("server")
  const allServersHref = "/servers" + (clearParams.size ? "?" + clearParams : "")
  const { mode, backendUrl } = useDataSource()
  const isLive = mode === "live"

  const [serverList,   setServerList]   = useState<Server[]>([])
  const [listState, setListState] = useState<"loading" | "ready" | "error">("loading")
  const { search, setSearch, typeFilter, setTypeFilter, filters: advancedFilters, setFilters: setAdvancedFilters, error: urlError, hasFilters, reset: resetFilters } = useServerUrlState()
  const [open,         setOpen]         = useState(false)
  const [sheetMode,    setSheetMode]    = useState<SheetMode>("add")
  const [editingId,    setEditingId]    = useState<string | null>(null)
  const [sheetStep,    setSheetStep]    = useState(1)
  const [form,         setForm]         = useState<FormState>(defaultForm)
  const [testState,    setTestState]    = useState<TestState>("idle")
  const [testMsg,      setTestMsg]      = useState("")
  const [pollingIds,   setPollingIds]   = useState<Set<string>>(new Set())
  const [pollAllBusy,  setPollAllBusy]  = useState(false)
  const [saving, setSaving] = useState(false)
  const [detailsLoading, setDetailsLoading] = useState(false)
  const [detailsReady, setDetailsReady] = useState(true)
  const [formError, setFormError] = useState("")
  const [operationMessage, setOperationMessage] = useState("")
  const [operationError, setOperationError] = useState("")
  const [deleteTarget, setDeleteTarget] = useState<Server | null>(null)
  const [deleting, setDeleting] = useState(false)
  const [deleteError, setDeleteError] = useState("")
  const [pollResults, setPollResults] = useState<PollResult[]>([])
  const [rowBusy, setRowBusy] = useState(false)
  const gate = useRef(new OperationGate())
  const formVersion = useRef(0)
  const testVersion = useRef(0)
  const contextVersion = useRef(0)
  const canWrite = can("mm:servers:write")
  const accessDenied = "Недостаточно прав: изменение и опрос серверов требуют разрешения на запись."
  function requireWrite(report: (message: string) => void = setOperationError) {
    if (can("mm:servers:write")) return true
    report(accessDenied)
    return false
  }
  const controlsBusy = saving || rowBusy || pollAllBusy || pollingIds.size > 0

  const set = <K extends keyof FormState>(k: K, v: FormState[K]) => {
    if (gate.current.has("save") || detailsLoading) return
    if (["host", "port", "proto", "verifySsl", "apiPath", "username", "password"].includes(k)) {
      testVersion.current++
      setTestState("idle"); setTestMsg("")
    }
    setForm((f) => ({ ...f, [k]: v }))
  }

  function closeForm(next: boolean) {
    if (gate.current.has("save")) return
    if (!next) { formVersion.current++; testVersion.current++ }
    setOpen(next)
  }

  // ── load from backend when mode/url changes ───────────────────────────────

  useEffect(() => {
    const version = ++contextVersion.current
    let cancelled = false
    const invalidate = () => {
      cancelled = true
      contextVersion.current++
      formVersion.current++
      testVersion.current++
    }
    queueMicrotask(() => {
      if (cancelled) return
      formVersion.current++; testVersion.current++
      setOpen(false); setDeleteTarget(null); setOperationError(""); setOperationMessage(""); setPollResults([])
      setListState("loading")
    })
    if (mode !== "live") {
      queueMicrotask(() => {
        if (cancelled) return
        setServerList(initialServers)
        setListState("ready")
      })
      return invalidate
    }
    listServers(backendUrl)
      .then(data => {
        if (cancelled || version !== contextVersion.current) return
        setListState("ready")
        setServerList(data.map(toFrontendServer))
      })
      .catch((error) => {
        if (cancelled || version !== contextVersion.current) return
        setOperationError(serverOperationError(error))
        setListState("error")
        setServerList([])
      })
    return invalidate
  }, [mode, backendUrl])

  // ── actions ──────────────────────────────────────────────────────────────

  function openAdd() {
    if (!requireWrite()) return
    if (gate.current.has("save")) return
    formVersion.current++; testVersion.current++
    setFormError(""); setDetailsLoading(false); setDetailsReady(true)
    setSheetMode("add"); setEditingId(null)
    setForm(defaultForm); setTestState("idle"); setTestMsg("")
    setSheetStep(1)
    setOpen(true)
  }

  async function openEdit(s: Server) {
    if (!requireWrite()) return
    if (gate.current.has("save")) return
    const version = ++formVersion.current
    testVersion.current++
    setFormError(""); setDetailsLoading(isLive); setDetailsReady(!isLive)
    setSheetMode("edit"); setEditingId(s.id)
    setForm({
      ...defaultForm,
      name: s.name, type: s.type, site: s.site, country: s.country ?? "RU",
      asn: s.asn ?? "", enabled: s.enabled, host: s.host,
      comment: s.comment ?? "",
      lanSubnet: s.lanSubnet ?? "",
      wanUplinks: s.wanUplinks ? JSON.parse(JSON.stringify(s.wanUplinks)) : [],
    })
    setTestState("idle"); setTestMsg(""); setSheetStep(1); setOpen(true)

    // Fetch full server details (including credentials) from backend
    if (isLive) {
      try {
        const full = await getServer(backendUrl, s.id)
        if (version !== formVersion.current) return
        setForm(prev => ({
          ...prev,
          username:  full.username  ?? "",
          enabled: full.enabled,
          password:  full.password  ?? "",
          port:      String(full.port ?? 443),
          proto:     full.useSsl ? "https" : "http",
          verifySsl: full.verifySsl ?? false,
          lanSubnet: full.lanSubnet ?? prev.lanSubnet,
          wanUplinks:
            Array.isArray(full.wanUplinks) && full.wanUplinks.length
              ? JSON.parse(JSON.stringify(full.wanUplinks))
              : prev.wanUplinks,
        }))
        setDetailsReady(true)
      } catch (error) {
        if (version === formVersion.current) setFormError(serverOperationError(error))
      } finally {
        if (version === formVersion.current) setDetailsLoading(false)
      }
    }
  }

  async function handleSave() {
    if (!requireWrite(setFormError)) return
    if (!detailsReady || detailsLoading || !gate.current.acquire("save")) return
    const context = contextVersion.current
    setSaving(true); setFormError("")
    try {
    const payload: ServerCreate = {
      host:      form.host,
      port:      Number(form.port),
      username:  form.username,
      password:  form.password,
      useSsl:    form.proto === "https",
      verifySsl: form.verifySsl,
      name:      form.name,
      type:      form.type,
      site:      form.site,
      country:   form.country,
      asn:       form.asn,
      comment:   form.comment,
      enabled:   form.enabled,
      lanSubnet: form.lanSubnet.trim(),
      wanUplinks: form.type === "home-router" ? form.wanUplinks : [],
    }

    if (!form.host.trim() || !form.username.trim() || !Number.isInteger(payload.port) || payload.port! > 65535 || payload.port! < 1) {
      setFormError("Укажите хост, имя пользователя и порт от 1 до 65535.")
      setSheetStep(3)
      return
    }
    const validation = serverCreateSchema.safeParse(payload)
    if (!validation.success) {
      setFormError("Проверьте параметры сервера: " + validation.error.issues.map(i => i.path.join(".")).join(", "))
      return
    }

    if (isLive) {
      try {
        if (sheetMode === "edit" && editingId) {
          const updatedPayload: ServerUpdate = payload
          const updated = await updateServer(backendUrl, editingId, updatedPayload)
          if (context !== contextVersion.current) return
          setServerList(list => list.map(s => s.id === editingId ? toFrontendServer(updated) : s))
        } else {
          const created = await createServer(backendUrl, payload)
          if (context !== contextVersion.current) return
          setServerList(list => [...list, toFrontendServer(created)])
        }
      } catch (e) {
        if (context === contextVersion.current) setFormError(serverOperationError(e))
        return
      }
    } else {
      // offline mode — update local state only
      if (sheetMode === "edit" && editingId) {
        setServerList(list => list.map(s =>
          s.id === editingId
            ? {
                ...s,
                name: form.name,
                type: form.type,
                site: form.site,
                country: form.country,
                host: form.host,
                asn: form.asn,
                comment: form.comment,
                lanSubnet: form.lanSubnet || undefined,
                wanUplinks: form.type === "home-router" ? form.wanUplinks : undefined,
                enabled: form.enabled,
              }
            : s
        ))
      } else {
        setServerList(list => [...list, {
          id: `srv${Date.now()}`, name: form.name || form.host,
          host: form.host, type: form.type, site: form.site,
          country: form.country, asn: form.asn, model: "Unknown", os: "—",
          status: form.enabled ? "online" : "offline",
          enabled: form.enabled, latency: null, sessions: 0,
          comment: form.comment || undefined,
          lanSubnet: form.lanSubnet || undefined,
          wanUplinks: form.type === "home-router" ? form.wanUplinks : undefined,
        }])
      }
    }

    setOpen(false)
    formVersion.current++; testVersion.current++
    setOperationMessage(isLive ? "Сервер сохранён." : "Сервер сохранён в демо-режиме.")
    } finally {
      gate.current.release("save"); setSaving(false)
    }
  }

  async function handleToggleStatus(id: string) {
    if (!requireWrite()) return
    const server = serverList.find(s => s.id === id)
    if (!server || !gate.current.acquire("rows")) return
    const context = contextVersion.current
    setRowBusy(true); setOperationError(""); setOperationMessage("")
    try {
      let enabled = !server.enabled
      if (isLive) enabled = (await updateServer(backendUrl, id, { enabled })).enabled
      if (context !== contextVersion.current) return
      setServerList(list => list.map(s => s.id === id ? { ...s, enabled } : s))
      setOperationMessage(`${server.name}: ${enabled ? "включён" : "отключён"}${isLive ? "." : " (демо)."}`)
    } catch (error) {
      if (context === contextVersion.current) setOperationError(serverOperationError(error))
    } finally { gate.current.release("rows"); setRowBusy(false) }
  }

  async function handleDelete(id: string) {
    if (!requireWrite(setDeleteError)) return
    if (!gate.current.acquire("rows")) return
    const context = contextVersion.current
    setDeleting(true); setRowBusy(true); setDeleteError("")
    try {
      if (isLive) await deleteServer(backendUrl, id)
      if (context !== contextVersion.current) return
      setServerList(list => list.filter(s => s.id !== id))
      setDeleteTarget(null); setOperationError(""); setOperationMessage("Сервер удалён из списка.")
    } catch (error) {
      if (context === contextVersion.current) setDeleteError(serverOperationError(error))
    } finally { gate.current.release("rows"); setDeleting(false); setRowBusy(false) }
  }

  async function handlePoll(id: string) {
    await runPoll([id])
  }

  async function handlePollAll() {
    await runPoll(serverList.map(s => s.id))
  }

  async function runPoll(ids: string[]) {
    if (!requireWrite()) return
    if (!isLive || !gate.current.acquire("rows")) return
    const context = contextVersion.current
    setPollAllBusy(true); setPollingIds(new Set(ids)); setOperationError(""); setOperationMessage(""); setPollResults([])
    try {
      const results = await pollServers(ids, async id => {
        if (context !== contextVersion.current) throw new Error("Контекст изменился; опрос отменён.")
        if (!can("mm:servers:write")) throw new Error(accessDenied)
        await pollServer(backendUrl, id)
      })
      if (context !== contextVersion.current) return
      setPollResults(results)
      try {
        const data = await listServers(backendUrl)
        if (context === contextVersion.current) setServerList(data.map(toFrontendServer))
      } catch (error) {
        if (context === contextVersion.current) setOperationError("Опрос завершён, но список не обновлён. " + serverOperationError(error))
      }
    } finally {
      gate.current.release("rows"); setPollAllBusy(false); setPollingIds(new Set())
    }
  }

  async function handleTest() {
    if (!requireWrite(setFormError)) return
    if (!detailsReady || gate.current.has("save") || gate.current.has("test")) return
    const version = ++testVersion.current
    if (!form.host || !form.username) {
      setTestState("error"); setTestMsg("Заполните Хост и Имя пользователя"); return
    }
    gate.current.acquire("test")
    setTestState("testing"); setTestMsg("")
    try {
      const data = await testServerConnection(backendUrl, {
        host: form.host,
        port: Number(form.port) || (form.proto === "https" ? 443 : 80),
        useSsl: form.proto === "https",
        verifySsl: form.verifySsl,
        apiPath: form.apiPath || "/rest",
        username: form.username,
        password: form.password,
      })
      if (version !== testVersion.current) return
      if (data.success) {
        setTestState("ok");    setTestMsg(data.message)
      } else {
        setTestState("error"); setTestMsg(data.message)
      }
    } catch (error) {
      if (version !== testVersion.current) return
      setTestState("error")
      setTestMsg(serverOperationError(error))
    } finally {
      gate.current.release("test")
    }
  }

  // ── derived ──────────────────────────────────────────────────────────────

  const selectedServer = serverList.find(server => server.id === selectedServerId)

  const filtered = useMemo(() => {
    if (urlError) return []
    const base = serverList.filter(sv => {
      if (selectedServerId !== null && sv.id !== selectedServerId) return false
      if (typeFilter !== "all" && sv.type !== typeFilter) return false
      if (!search) return true
      const q = search.toLowerCase()
      return sv.name.toLowerCase().includes(q) || sv.host.includes(q) || sv.site.toLowerCase().includes(q)
    })
    return applyFilterQuery(base, advancedFilters, SERVER_FILTER_ACCESSORS)
  }, [serverList, search, typeFilter, advancedFilters, selectedServerId, urlError])

  const counts = useMemo(() => ({
    all:          serverList.length,
    "jump-host":  serverList.filter(s => s.type === "jump-host").length,
    "exit-node":  serverList.filter(s => s.type === "exit-node").length,
    "home-router":serverList.filter(s => s.type === "home-router").length,
    online:       serverList.filter(s => s.status === "online").length,
  }), [serverList])

  const tabs: { value: TypeFilter; label: string }[] = [
    { value: "all",          label: "Все"          },
    { value: "jump-host",    label: "JumpHost"      },
    { value: "exit-node",    label: "Exit Node"     },
    { value: "home-router",  label: "Home Router"   },
  ]

  const isHomeRouter = form.type === "home-router"

  // ─────────────────────────────────────────────────────────────────────────

  return (
    <div className="flex flex-col h-full">
      <PageHeader
        crumbs={[{ label: "Управление" }, { label: "Серверы" }]}
        actions={
          <>
            <Button variant="outline" size="sm" onClick={() => selectedServerId !== null ? selectedServer && void runPoll([selectedServer.id]) : void handlePollAll()} disabled={!canWrite || !isLive || controlsBusy || (selectedServerId !== null ? !selectedServer : serverList.length === 0)}>
              <RefreshCwIcon className={cn("size-4", pollAllBusy && "animate-spin")} />{selectedServerId !== null ? "Проверить сервер" : "Проверить все"}
            </Button>
            <Button size="sm" onClick={openAdd} disabled={!canWrite || controlsBusy}><PlusIcon className="size-4" />Добавить сервер</Button>
          </>
        }
      />

      <div className="flex-1 overflow-y-auto p-6">
        <div className="flex flex-col gap-5">

          {!canWrite && <Alert variant="info" role="status"><AlertTitle>Только просмотр</AlertTitle><AlertDescription>Изменение, удаление, опрос серверов и тест соединения требуют разрешения на запись. Просмотр деталей и фильтры доступны.</AlertDescription></Alert>}
          {operationError && <Alert variant="destructive" role="alert"><AlertTitle>Действие не завершено</AlertTitle><AlertDescription>{operationError}</AlertDescription></Alert>}
          {operationMessage && <Alert variant="success" role="status"><AlertDescription>{operationMessage}</AlertDescription></Alert>}
          {pollResults.length > 0 && (
            <Alert variant={pollResults.some(r => r.error) ? "warning" : "success"} role="status">
              <AlertTitle>Опрос: успешно {pollResults.filter(r => !r.error).length} из {pollResults.length}</AlertTitle>
              <AlertDescription>
                <ul>{pollResults.map(r => <li key={r.id}>{serverList.find(s => s.id === r.id)?.name ?? r.id}: {r.error ?? "опрос выполнен"}</li>)}</ul>
                {pollResults.some(r => r.error) && <Button type="button" variant="outline" size="sm" disabled={!canWrite || controlsBusy} onClick={() => runPoll(pollResults.filter(r => r.error).map(r => r.id))}>Повторить неуспешные</Button>}
              </AlertDescription>
            </Alert>
          )}

          {selectedServerId !== null && (
            <Alert variant={listState === "error" || (listState === "ready" && !selectedServer) ? "warning" : "info"} role="status" aria-label="Сервер по ссылке">
              <AlertTitle className="line-clamp-none wrap-anywhere">{selectedServer ? "Выбран сервер: " + selectedServer.name : "Сервер по ссылке"}</AlertTitle>
              <AlertDescription>
                <p>{listState === "loading" ? "Загрузка сервера…" : listState === "error" ? "Не удалось загрузить сервер. Проверьте сообщение об ошибке выше." : selectedServer ? selectedServer.host + " · Список ограничен выбранным сервером. Сводка относится ко всем серверам." : "Сервер не найден или недоступен. Возможно, он удалён или у вас нет доступа."}</p>
                <div className="flex flex-wrap gap-4">
                  <Link href={allServersHref} className="underline underline-offset-2">Все серверы</Link>
                  <Link href="/dashboard" className="underline underline-offset-2">К дашборду</Link>
                </div>
              </AlertDescription>
            </Alert>
          )}

          <KpiStatGrid
            aria-label="Сводка серверов"
            items={[
              {
                id: "all",
                label: "Всего серверов",
                value: counts.all,
                icon: <ServerIcon className="size-4" />,
                iconClassName: "text-muted-foreground",
              },
              {
                id: "online",
                label: "Онлайн",
                value: counts.online,
                icon: <CheckCircleIcon className="size-4" />,
                iconClassName: "text-success",
              },
              {
                id: "jh-en",
                label: "JH + Exit Node",
                value: counts["jump-host"] + counts["exit-node"],
                icon: <NetworkIcon className="size-4" />,
                iconClassName: "text-muted-foreground",
              },
              {
                id: "home",
                label: "Home Router",
                value: counts["home-router"],
                icon: <HomeIcon className="size-4" />,
                iconClassName: "text-muted-foreground",
              },
            ]}
          />

          {/* Table */}
          {urlError && <Alert variant="warning" role="alert"><AlertTitle>Фильтры требуют внимания</AlertTitle><AlertDescription>{urlError}</AlertDescription></Alert>}
          {hasFilters && <div><Button variant="outline" size="sm" onClick={resetFilters}>Сбросить фильтры списка</Button></div>}
          <DataPageCard>
            <DataPageToolbar
              segmented={{
                value: typeFilter,
                onChange: setTypeFilter,
                options: tabs.map((tab) => ({
                  value: tab.value,
                  label: tab.label,
                  count: tab.value === "all" ? counts.all : counts[tab.value as ServerType],
                })),
              }}
              filterControl={<ServerFilters query={advancedFilters} onQueryChange={setAdvancedFilters} />}
              search={search}
              onSearchChange={setSearch}
              searchPlaceholder="Поиск по имени, хосту…"
              countLabel={`${filtered.length} серверов`}
            />
            <ServersDataGrid
              servers={filtered}
              hasUnfilteredRows={serverList.length > 0}
              isLive={isLive}
              pollingIds={pollingIds}
              busy={controlsBusy}
              canWrite={canWrite}
              onPoll={handlePoll}
              onEdit={openEdit}
              onDelete={id => { if (!requireWrite()) return; setDeleteError(""); setDeleteTarget(serverList.find(s => s.id === id) ?? null) }}
              onToggleStatus={handleToggleStatus}
            />
          </DataPageCard>
        </div>
      </div>

      {/* ══ Sheet: Add / Edit Server ══════════════════════════════════════════ */}
      <Sheet open={open} onOpenChange={closeForm}>
        <SheetContent side="right" showCloseButton={!saving} className="data-[side=right]:w-full sm:max-w-lg flex flex-col gap-0 p-0">
          <SheetHeader className="px-6 pt-6 pb-4 border-b shrink-0">
            <SheetTitle>{sheetMode === "edit" ? "Редактировать сервер" : "Новый сервер"}</SheetTitle>
            <SheetDescription>MikroTik RouterOS · Web API (REST)</SheetDescription>
          </SheetHeader>

          {detailsLoading && <p className="px-6 py-2 text-sm" role="status">Загрузка параметров сервера…</p>}
          {formError && <div className="px-6 py-2"><Alert variant="destructive" role="alert"><AlertDescription>{formError}</AlertDescription></Alert>
            {!detailsReady && !detailsLoading && editingId && <Button type="button" variant="outline" onClick={() => { const server = serverList.find(s => s.id === editingId); if (server) void openEdit(server) }}>Повторить загрузку</Button>}
          </div>}

          <fieldset disabled={!canWrite || saving || !detailsReady} className="flex min-h-0 min-w-0 flex-1 flex-col" aria-busy={saving || detailsLoading}>
          <Stepper value={sheetStep} onValueChange={setSheetStep} className="flex-1 flex flex-col min-h-0 px-6 py-5">
            <StepperNav className="mb-5">
              <StepperItem step={1}>
                <StepperTrigger>
                  <StepperIndicator>1</StepperIndicator>
                  <StepperTitle className="sr-only">Основные</StepperTitle>
                </StepperTrigger>
                <StepperSeparator />
              </StepperItem>
              <StepperItem step={2}>
                <StepperTrigger>
                  <StepperIndicator>2</StepperIndicator>
                  <StepperTitle className="sr-only">WAN</StepperTitle>
                </StepperTrigger>
                <StepperSeparator />
              </StepperItem>
              <StepperItem step={3}>
                <StepperTrigger>
                  <StepperIndicator>3</StepperIndicator>
                  <StepperTitle className="sr-only">API</StepperTitle>
                </StepperTrigger>
                <StepperSeparator />
              </StepperItem>
              <StepperItem step={4}>
                <StepperTrigger>
                  <StepperIndicator>4</StepperIndicator>
                  <StepperTitle className="sr-only">Дополнительно</StepperTitle>
                </StepperTrigger>
              </StepperItem>
            </StepperNav>
            <StepperPanel className="flex-1 overflow-y-auto">
              <StepperContent value={1} className="flex flex-col gap-4">

              <FormField label="Имя сервера" required hint="Например home-msk-01">
                <Input className="font-mono" placeholder="home-msk-01"
                  value={form.name} onChange={e => set("name", e.target.value)} />
              </FormField>

              <FormField label="Тип узла" required>
                <SegmentedControl
                  className="max-w-full flex-wrap"
                  value={form.type}
                  onChange={v => set("type", v)}
                  options={[
                    { value: "home-router", label: "Home Router" },
                    { value: "jump-host",   label: "JumpHost"    },
                    { value: "exit-node",   label: "Exit Node"   },
                  ]}
                />
              </FormField>

              <div className="grid grid-cols-2 gap-3">
                <FormField label="Площадка" required hint="MSK, SPB, FRA…">
                  <Input className="font-mono uppercase" placeholder="MSK"
                    value={form.site} onChange={e => set("site", e.target.value.toUpperCase())} />
                </FormField>
                {!isHomeRouter && (
                  <FormField label="ASN" hint="Например AS65001">
                    <Input className="font-mono" placeholder="AS65001"
                      value={form.asn} onChange={e => set("asn", e.target.value)} />
                  </FormField>
                )}
                {isHomeRouter && (
                  <FormField label="LAN-подсеть" hint="Например 192.168.10.0/24">
                    <Input className="font-mono" placeholder="192.168.10.0/24"
                      value={form.lanSubnet} onChange={e => set("lanSubnet", e.target.value)} />
                  </FormField>
                )}
              </div>

              <CountryField value={form.country} onChange={v => set("country", v)} />

              <div className="flex items-center justify-between">
                <span className="text-sm font-medium">Включён</span>
                <FormToggle checked={form.enabled} onChange={v => set("enabled", v)} />
              </div>
              </StepperContent>
              <StepperContent value={2} className="flex flex-col gap-4">
                <SectionTitle>WAN-аплинки</SectionTitle>
                {!isHomeRouter ? (
                  <p className="text-sm text-muted-foreground">WAN-аплинки доступны только для типа Home Router.</p>
                ) : (
                <WanUplinkEditor
                  wans={form.wanUplinks}
                  onChange={wans => set("wanUplinks", wans)}
                />
                )}
              </StepperContent>
              <StepperContent value={3} className="flex flex-col gap-4">
              <SectionTitle>Подключение (RouterOS REST API)</SectionTitle>

              <FormField label="Хост / IP-адрес" required
                hint={isHomeRouter
                  ? "Управляющий LAN-адрес роутера, например 192.168.10.1"
                  : "Внешний или управляющий IP-адрес роутера"}>
                <Input className="font-mono" placeholder={isHomeRouter ? "192.168.10.1" : "203.0.113.1"}
                  value={form.host} onChange={e => set("host", e.target.value)} />
              </FormField>

              <div className="grid grid-cols-2 gap-3">
                <FormField label="Протокол">
                  <SegmentedControl
                    value={form.proto}
                    onChange={v => { set("proto", v); set("port", v === "https" ? "443" : "80") }}
                    options={[{ value: "https", label: "HTTPS" }, { value: "http", label: "HTTP" }]}
                  />
                </FormField>
                <FormField label="Порт" hint="443 / 80">
                  <Input className="font-mono" placeholder="443"
                    value={form.port} onChange={e => set("port", e.target.value)} />
                </FormField>
              </div>

              <div className="flex items-center justify-between">
                <div>
                  <p className="text-sm font-medium flex items-center gap-1.5">
                    <ShieldIcon className="size-3.5 text-muted-foreground" />
                    Проверять SSL-сертификат
                  </p>
                  <p className="text-xs text-muted-foreground">Отключить для self-signed сертификатов</p>
                </div>
                <FormToggle checked={form.verifySsl} onChange={v => set("verifySsl", v)} />
              </div>

              <FormField label="Путь API">
                <Input className="font-mono" placeholder="/rest"
                  value={form.apiPath} onChange={e => set("apiPath", e.target.value)} />
              </FormField>

              <div className="rounded-lg border border-border bg-muted/20 px-4 py-3 text-xs text-muted-foreground">
                <p className="font-medium text-foreground mb-1">RouterOS 7.1+ REST API</p>
                <p className="font-mono text-foreground">
                  {form.proto}://{form.host || "host"}:{form.port}{form.apiPath}
                </p>
                {isHomeRouter && (
                  <p className="mt-1 text-amber-600 dark:text-amber-400">
                    ⚠ Home Router доступен только из LAN / через VPN-туннель
                  </p>
                )}
              </div>

              <FormField label="Имя пользователя" required hint="Пользователь RouterOS с доступом к API">
                <Input className="font-mono" placeholder="api-user"
                  value={form.username} onChange={e => set("username", e.target.value)} />
              </FormField>

              <FormField label="Пароль" required>
                <div className="relative">
                  <Input type={form.showPassword ? "text" : "password"}
                    className="font-mono pr-9" placeholder="Пароль пользователя RouterOS"
                    value={form.password} onChange={e => set("password", e.target.value)} />
                  <button type="button"
                    onClick={() => set("showPassword", !form.showPassword)}
                    className="absolute right-2.5 top-1/2 -translate-y-1/2 text-muted-foreground hover:text-foreground">
                    {form.showPassword ? <EyeOffIcon className="size-3.5" /> : <EyeIcon className="size-3.5" />}
                  </button>
                </div>
              </FormField>

              <div className="flex flex-col gap-2">
                <Button type="button" variant="outline" size="sm" className="w-fit gap-2"
                  disabled={!canWrite || testState === "testing"} onClick={handleTest}>
                  {testState === "testing"
                    ? <><LoaderCircleIcon className="size-4 animate-spin" />Проверка…</>
                    : <><WifiIcon className="size-4" />Проверить подключение</>}
                </Button>
                {testState === "ok" && (
                  <div className="flex items-start gap-2 rounded-md border border-current/25 px-3 py-2 text-xs"
                    style={{ background: "var(--status-online-bg)", color: "var(--status-online-fg)" }}>
                    <CheckCircleIcon className="size-3.5 shrink-0 mt-0.5" /><span>{testMsg}</span>
                  </div>
                )}
                {testState === "error" && (
                  <div className="flex items-start gap-2 rounded-md border border-current/25 px-3 py-2 text-xs"
                    style={{ background: "var(--status-offline-bg)", color: "var(--status-offline-fg)" }}>
                    <XCircleIcon className="size-3.5 shrink-0 mt-0.5" /><span>{testMsg}</span>
                  </div>
                )}
              </div>
              </StepperContent>
              <StepperContent value={4} className="flex flex-col gap-4">
              <button type="button" onClick={() => set("showAdvanced", !form.showAdvanced)}
                className="flex items-center gap-2 text-xs font-semibold uppercase tracking-wider text-muted-foreground hover:text-foreground transition-colors">
                {form.showAdvanced ? <ChevronDownIcon className="size-3.5" /> : <ChevronRightIcon className="size-3.5" />}
                Дополнительно
                <div className="flex-1 h-px bg-border" />
              </button>
              {form.showAdvanced && (
                <div className="flex flex-col gap-4">
                  <div className="grid grid-cols-2 gap-3">
                    <FormField label="SSH-порт">
                      <Input type="number" className="font-mono" value={form.sshPort}
                        onChange={e => set("sshPort", Number(e.target.value))} />
                    </FormField>
                    <FormField label="Winbox-порт">
                      <Input type="number" className="font-mono" value={form.winboxPort}
                        onChange={e => set("winboxPort", Number(e.target.value))} />
                    </FormField>
                  </div>
                  <FormField label="Таймаут соединения, с">
                    <Input type="number" className="font-mono" value={form.timeout}
                      onChange={e => set("timeout", Number(e.target.value))} />
                  </FormField>
                  <FormField label="Комментарий">
                    <Input placeholder="Описание или заметка" value={form.comment}
                      onChange={e => set("comment", e.target.value)} />
                  </FormField>
                </div>
              )}
              </StepperContent>
            </StepperPanel>
          </Stepper>
          </fieldset>

          <SheetFooter className="px-6 py-4 border-t shrink-0 flex-row flex-wrap gap-2">
            <SheetClose render={<Button variant="outline" disabled={saving} />}>Отмена</SheetClose>
            {sheetStep > 1 && (
              <Button variant="outline" disabled={saving || !detailsReady} onClick={() => setSheetStep((s) => s - 1)}>Назад</Button>
            )}
            {sheetStep < 4 ? (
              <Button className="ml-auto" disabled={saving || !detailsReady} onClick={() => setSheetStep((s) => s + 1)}>Далее</Button>
            ) : (
              <Button className="ml-auto" disabled={!canWrite || saving || !detailsReady || testState === "testing"} onClick={handleSave}>
                {saving ? "Сохранение…" : sheetMode === "edit" ? "Сохранить" : "Добавить сервер"}
              </Button>
            )}
          </SheetFooter>
        </SheetContent>
      </Sheet>
      <AlertDialog open={deleteTarget !== null} onOpenChange={next => { if (!next && !gate.current.has("rows")) setDeleteTarget(null) }}>
        <AlertDialogContent>
          <AlertDialogHeader>
            <AlertDialogTitle>Удалить сервер?</AlertDialogTitle>
            <AlertDialogDescription>Сервер «{deleteTarget?.name}» ({deleteTarget?.host}) будет удалён из списка управления.</AlertDialogDescription>
          </AlertDialogHeader>
          {deleteError && <p role="alert" className="text-sm text-destructive">{deleteError}</p>}
          <AlertDialogFooter>
            <Button type="button" variant="outline" disabled={deleting} onClick={() => setDeleteTarget(null)}>Отмена</Button>
            <Button type="button" variant="destructive" disabled={!canWrite || deleting} onClick={() => { if (deleteTarget) void handleDelete(deleteTarget.id) }}>{deleting ? "Удаление…" : "Удалить"}</Button>
          </AlertDialogFooter>
        </AlertDialogContent>
      </AlertDialog>
    </div>
  )
}

export default function ServersPage() {
  return <Suspense fallback={<p role="status" className="p-6">Загрузка серверов…</p>}><ServersPageContent /></Suspense>
}