"use client"

import { useMemo, useState } from "react"
import { PageHeader } from "@/components/page-header"
import { EmptyState } from "@/components/empty-state"
import { servers } from "@/lib/data"
import type { WireGuardInterface, WireGuardPeer } from "@/lib/data"
import { Flag } from "@/components/flag"
import { Card, CardContent } from "@/components/ui/card"
import { Button } from "@/components/ui/button"
import { cn } from "@/lib/utils"
import {
  Sheet, SheetContent, SheetHeader, SheetTitle,
  SheetDescription, SheetFooter, SheetClose,
} from "@/components/ui/sheet"
import {
  DropdownMenu, DropdownMenuTrigger, DropdownMenuContent,
  DropdownMenuItem, DropdownMenuSeparator,
} from "@/components/ui/dropdown-menu"
import {
  ShieldCheckIcon, PlusIcon, SearchIcon, KeyRoundIcon,
  ChevronDownIcon, ChevronRightIcon, MoreHorizontalIcon,
  PencilIcon, Trash2Icon, PowerIcon, CopyIcon, CheckIcon,
  CodeXmlIcon, UsersIcon, ActivityIcon, ArrowDownIcon, ArrowUpIcon,
} from "lucide-react"

// ─── collect all WireGuard interfaces from all servers ────────────────────────

interface WgIfaceWithServer extends WireGuardInterface {
  serverId: string
  serverName: string
  serverCountry: string
}

function collectInterfaces(): WgIfaceWithServer[] {
  const result: WgIfaceWithServer[] = []
  for (const srv of servers) {
    for (const wg of srv.wireGuardIfaces ?? []) {
      result.push({
        ...wg,
        serverId: srv.id,
        serverName: srv.name,
        serverCountry: srv.country,
      })
    }
  }
  return result
}

// ─── helpers ──────────────────────────────────────────────────────────────────

function fmtBytes(n: number | undefined): string {
  if (!n) return "—"
  if (n >= 1_000_000_000) return `${(n / 1_000_000_000).toFixed(1)} ГБ`
  if (n >= 1_000_000) return `${(n / 1_000_000).toFixed(1)} МБ`
  if (n >= 1_000) return `${(n / 1_000).toFixed(0)} КБ`
  return `${n} Б`
}

function truncKey(key: string): string {
  if (key.length <= 20) return key
  return `${key.slice(0, 8)}…${key.slice(-8)}`
}

// ─── RSC generator ────────────────────────────────────────────────────────────

function generateWgRsc(iface: WgIfaceWithServer): string {
  const lines: string[] = []
  lines.push(`# WireGuard — ${iface.name} · ${iface.serverName}`)
  lines.push(`# RouterOS 7.x`)
  lines.push(``)
  lines.push(`/interface wireguard add \\`)
  lines.push(`  name=${iface.name} \\`)
  lines.push(`  listen-port=${iface.listenPort} \\`)
  lines.push(`  mtu=${iface.mtu} \\`)
  if (iface.comment) lines.push(`  comment="${iface.comment}" \\`)
  if (!iface.enabled) lines.push(`  disabled=yes \\`)
  lines.push(``)
  for (const p of iface.peers) {
    lines.push(`/interface wireguard peers add \\`)
    lines.push(`  interface=${iface.name} \\`)
    lines.push(`  public-key="${p.publicKey}" \\`)
    lines.push(`  allowed-address=${p.allowedIps.join(",")} \\`)
    if (p.endpoint) lines.push(`  endpoint-address=${p.endpoint.split(":")[0]} \\`)
    if (p.endpoint) lines.push(`  endpoint-port=${p.endpoint.split(":")[1] ?? "13231"} \\`)
    if (p.persistent) lines.push(`  persistent-keepalive=25 \\`)
    if (p.comment) lines.push(`  comment="${p.comment}" \\`)
    lines.push(``)
  }
  return lines.join("\n")
}

// ─── Peer row ─────────────────────────────────────────────────────────────────

function PeerRow({ peer }: { peer: WireGuardPeer }) {
  return (
    <div className="grid grid-cols-[1fr_1fr_auto_auto_auto] gap-3 px-4 py-2.5 items-center text-xs border-t border-border/50 bg-muted/20">
      {/* public key */}
      <div className="flex items-center gap-1.5 min-w-0">
        <KeyRoundIcon className="size-3 text-muted-foreground shrink-0" />
        <span className="font-mono text-muted-foreground truncate" title={peer.publicKey}>
          {truncKey(peer.publicKey)}
        </span>
      </div>
      {/* allowed IPs */}
      <div className="font-mono text-muted-foreground truncate">
        {peer.allowedIps.join(", ")}
      </div>
      {/* handshake */}
      <span className={cn(
        "font-mono text-[11px] whitespace-nowrap",
        peer.latestHandshake ? "text-emerald-600 dark:text-emerald-400" : "text-muted-foreground",
      )}>
        {peer.latestHandshake ?? "нет рукопожатия"}
      </span>
      {/* rx / tx */}
      <div className="flex items-center gap-2 text-muted-foreground whitespace-nowrap">
        <span className="flex items-center gap-0.5">
          <ArrowDownIcon className="size-3 text-emerald-500" />{fmtBytes(peer.transferRx)}
        </span>
        <span className="flex items-center gap-0.5">
          <ArrowUpIcon className="size-3 text-blue-400" />{fmtBytes(peer.transferTx)}
        </span>
      </div>
      {/* endpoint */}
      <span className="font-mono text-muted-foreground/60 text-[11px]">{peer.endpoint ?? "—"}</span>
    </div>
  )
}

// ─── Interface card ───────────────────────────────────────────────────────────

function IfaceRow({
  iface,
  expanded,
  onToggleExpand,
  onExport,
}: {
  iface: WgIfaceWithServer
  expanded: boolean
  onToggleExpand: () => void
  onExport: () => void
}) {
  const onlinePeers = iface.peers.filter((p) => !!p.latestHandshake).length

  return (
    <div className={cn("border-b last:border-b-0", !iface.enabled && "opacity-50")}>
      <div
        className="grid grid-cols-[20px_1fr_auto_auto_auto_auto_auto_auto] gap-3 px-4 py-3 items-center hover:bg-muted/30 transition-colors cursor-pointer"
        onClick={onToggleExpand}
      >
        {/* expand */}
        <button className="text-muted-foreground" onClick={(e) => { e.stopPropagation(); onToggleExpand() }}>
          {expanded
            ? <ChevronDownIcon className="size-3.5" />
            : <ChevronRightIcon className="size-3.5" />}
        </button>

        {/* name + server */}
        <div className="min-w-0">
          <div className="flex items-center gap-2">
            <span className={cn(
              "size-2 rounded-full shrink-0",
              iface.status === "up" ? "bg-emerald-500 animate-pulse" : "bg-red-500",
            )} />
            <span className="font-mono font-semibold text-sm">{iface.name}</span>
          </div>
          <div className="flex items-center gap-1.5 mt-0.5 text-[11px] text-muted-foreground font-mono">
            <Flag code={iface.serverCountry} size={12} />
            {iface.serverName}
          </div>
        </div>

        {/* port */}
        <div className="text-center">
          <p className="text-[10px] text-muted-foreground">Порт</p>
          <p className="font-mono text-sm">{iface.listenPort}</p>
        </div>

        {/* MTU */}
        <div className="text-center">
          <p className="text-[10px] text-muted-foreground">MTU</p>
          <p className="font-mono text-sm">{iface.mtu}</p>
        </div>

        {/* peers */}
        <div className="text-center">
          <p className="text-[10px] text-muted-foreground">Пиров</p>
          <p className="font-mono text-sm">
            <span className="text-emerald-600 dark:text-emerald-400">{onlinePeers}</span>
            <span className="text-muted-foreground">/{iface.peers.length}</span>
          </p>
        </div>

        {/* status badge */}
        <span className={cn(
          "text-[11px] font-mono px-2 py-0.5 rounded border",
          iface.status === "up"
            ? "bg-emerald-500/10 text-emerald-600 dark:text-emerald-400 border-emerald-500/20"
            : "bg-red-500/10 text-red-500 border-red-500/20",
        )}>
          {iface.status === "up" ? "UP" : "DOWN"}
        </span>

        {/* menu */}
        <DropdownMenu>
          <DropdownMenuTrigger render={
            <Button variant="ghost" size="icon" className="size-7" onClick={(e) => e.stopPropagation()}>
              <MoreHorizontalIcon className="size-4" />
            </Button>
          } />
          <DropdownMenuContent side="bottom" align="end">
            <DropdownMenuItem onClick={(e) => { e.stopPropagation(); onExport() }}>
              <CodeXmlIcon className="size-4" />Экспорт .rsc
            </DropdownMenuItem>
            <DropdownMenuItem><PencilIcon className="size-4" />Редактировать</DropdownMenuItem>
            <DropdownMenuItem><PlusIcon className="size-4" />Добавить пира</DropdownMenuItem>
            <DropdownMenuSeparator />
            <DropdownMenuItem><PowerIcon className="size-4" />{iface.enabled ? "Отключить" : "Включить"}</DropdownMenuItem>
            <DropdownMenuSeparator />
            <DropdownMenuItem variant="destructive"><Trash2Icon className="size-4" />Удалить</DropdownMenuItem>
          </DropdownMenuContent>
        </DropdownMenu>
      </div>

      {/* expanded peers */}
      {expanded && iface.peers.length > 0 && (
        <div>
          <div className="grid grid-cols-[1fr_1fr_auto_auto_auto] gap-3 px-4 py-1.5 bg-muted/10 text-[10px] font-semibold uppercase tracking-widest text-muted-foreground border-t border-border/50">
            <span>Public Key</span>
            <span>Allowed IPs</span>
            <span>Последнее рукопожатие</span>
            <span>RX / TX</span>
            <span>Endpoint</span>
          </div>
          {iface.peers.map((p) => <PeerRow key={p.publicKey} peer={p} />)}
        </div>
      )}
      {expanded && iface.peers.length === 0 && (
        <div className="px-4 py-4 text-xs text-muted-foreground text-center border-t border-border/50">
          Нет пиров
        </div>
      )}
    </div>
  )
}

// ─── Export Sheet ─────────────────────────────────────────────────────────────

function ExportSheet({ open, iface, onClose }: {
  open: boolean; iface: WgIfaceWithServer | null; onClose: () => void
}) {
  const [copied, setCopied] = useState(false)
  const code = useMemo(() => iface ? generateWgRsc(iface) : "", [iface])

  function handleCopy() {
    navigator.clipboard.writeText(code).then(() => {
      setCopied(true); setTimeout(() => setCopied(false), 2000)
    })
  }

  return (
    <Sheet open={open} onOpenChange={(v) => { if (!v) onClose() }}>
      <SheetContent className="flex flex-col overflow-hidden p-0 gap-0 sm:max-w-2xl">
        <SheetHeader className="shrink-0 px-6 pt-5 pb-4 border-b">
          <div className="flex items-start justify-between gap-4">
            <div>
              <SheetTitle>Экспорт WireGuard</SheetTitle>
              <SheetDescription>RouterOS 7.x · /interface wireguard + peers</SheetDescription>
            </div>
            <Button variant="outline" size="sm" className="shrink-0" onClick={handleCopy}>
              {copied
                ? <><CheckIcon className="size-3.5 text-emerald-500" />Скопировано</>
                : <><CopyIcon className="size-3.5" />Копировать</>}
            </Button>
          </div>
        </SheetHeader>
        <div className="flex-1 overflow-y-auto">
          <pre className="px-6 py-5 text-[12px] font-mono leading-relaxed text-foreground/85 whitespace-pre select-all">
            {code.split("\n").map((line, i) => {
              const isComment = line.startsWith("#")
              const isCmd = line.trimStart().startsWith("/interface")
              const isParam = /^\s+[a-z]/.test(line)
              return (
                <span key={i} className={
                  isComment ? "text-muted-foreground"
                  : isCmd    ? "text-sky-400"
                  : isParam  ? "text-violet-300"
                  : "text-foreground"
                }>
                  {line}{"\n"}
                </span>
              )
            })}
          </pre>
        </div>
        <SheetFooter className="shrink-0 px-6 py-4 border-t flex-row gap-2">
          <SheetClose render={<Button variant="outline" className="flex-1" />}>Закрыть</SheetClose>
          <Button className="flex-1" onClick={handleCopy}>
            {copied ? <CheckIcon className="size-4" /> : <CopyIcon className="size-4" />}
            {copied ? "Скопировано" : "Копировать .rsc"}
          </Button>
        </SheetFooter>
      </SheetContent>
    </Sheet>
  )
}

// ════════════════════════════════════════════════════════════════════════════
export default function WireGuardPage() {
  const allIfaces = useMemo(() => collectInterfaces(), [])

  const [search, setSearch]           = useState("")
  const [expandedIds, setExpandedIds] = useState<Set<string>>(new Set())
  const [exportIface, setExportIface] = useState<WgIfaceWithServer | null>(null)

  const filtered = useMemo(() => {
    if (!search) return allIfaces
    const q = search.toLowerCase()
    return allIfaces.filter((i) =>
      i.name.includes(q) ||
      i.serverName.toLowerCase().includes(q) ||
      i.peers.some((p) => p.allowedIps.some((a) => a.includes(q)) || (p.endpoint ?? "").includes(q))
    )
  }, [allIfaces, search])

  const totalPeers   = allIfaces.reduce((s, i) => s + i.peers.length, 0)
  const onlinePeers  = allIfaces.reduce((s, i) => s + i.peers.filter((p) => !!p.latestHandshake).length, 0)
  const upIfaces     = allIfaces.filter((i) => i.status === "up").length

  function toggleExpand(id: string) {
    setExpandedIds((prev) => {
      const next = new Set(prev)
      if (next.has(id)) next.delete(id); else next.add(id)
      return next
    })
  }

  return (
    <div className="flex flex-col h-full">
      <PageHeader
        crumbs={[{ label: "Управление" }, { label: "WireGuard" }]}
        actions={
          <>
            <Button size="sm">
              <PlusIcon className="size-4" />Новый интерфейс
            </Button>
          </>
        }
      />

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

          {/* KPI */}
          <div className="grid grid-cols-2 lg:grid-cols-4 gap-4">
            {[
              { label: "Интерфейсов",   value: allIfaces.length,            icon: <ShieldCheckIcon className="size-4 text-muted-foreground" /> },
              { label: "Активных (UP)", value: upIfaces,                    icon: <ActivityIcon className="size-4 text-emerald-500" /> },
              { label: "Всего пиров",   value: totalPeers,                  icon: <UsersIcon className="size-4 text-sky-400" /> },
              { label: "Пиров онлайн",  value: `${onlinePeers}/${totalPeers}`, icon: <KeyRoundIcon className="size-4 text-violet-400" /> },
            ].map((s) => (
              <Card key={s.label}>
                <CardContent className="px-5 py-4 flex items-start justify-between">
                  <div>
                    <p className="text-sm text-muted-foreground">{s.label}</p>
                    <p className="text-2xl font-semibold tabular-nums mt-0.5">{s.value}</p>
                  </div>
                  <div className="mt-0.5">{s.icon}</div>
                </CardContent>
              </Card>
            ))}
          </div>

          {/* Info banner */}
          <div className="flex items-start gap-3 rounded-lg bg-sky-500/5 border border-sky-500/20 px-4 py-3 text-sm">
            <ShieldCheckIcon className="size-5 text-sky-500 shrink-0 mt-0.5" />
            <div>
              <p className="font-medium text-sky-600 dark:text-sky-400">WireGuard — рекомендуемый туннельный протокол в RouterOS 7.x</p>
              <p className="text-muted-foreground text-xs mt-0.5">
                Доступен с RouterOS 7.1+. Более высокая производительность и безопасность по сравнению с GRE+IPsec.
                Ключи генерируются командой <code className="font-mono bg-muted px-1 rounded">/interface/wireguard/print</code>.
              </p>
            </div>
          </div>

          {/* Search + table */}
          <Card>
            <div className="flex items-center gap-3 px-4 py-3 border-b">
              <div className="flex items-center gap-2 h-8 px-3 border border-input rounded-md bg-background min-w-[260px]">
                <SearchIcon className="size-3.5 text-muted-foreground shrink-0" />
                <input
                  className="flex-1 bg-transparent outline-none placeholder:text-muted-foreground text-sm"
                  placeholder="Поиск по имени, серверу, IP…"
                  value={search}
                  onChange={(e) => setSearch(e.target.value)}
                />
              </div>
              <span className="text-sm text-muted-foreground ml-auto">{filtered.length} интерфейсов</span>
            </div>

            {/* table header */}
            <div className="grid grid-cols-[20px_1fr_auto_auto_auto_auto_auto_auto] gap-3 px-4 py-2 border-b text-[10px] font-semibold uppercase tracking-widest text-muted-foreground bg-muted/20">
              <span />
              <span>Интерфейс / Сервер</span>
              <span>Порт</span>
              <span>MTU</span>
              <span>Пиры</span>
              <span>Статус</span>
              <span />
            </div>

            {filtered.length === 0 ? (
              <EmptyState
                icon={<ShieldCheckIcon className="size-4" />}
                title="Нет WireGuard интерфейсов"
                description="Добавьте первый интерфейс или проверьте поиск"
                className="border-0 py-16"
              />
            ) : (
              filtered.map((iface) => (
                <IfaceRow
                  key={iface.id}
                  iface={iface}
                  expanded={expandedIds.has(iface.id)}
                  onToggleExpand={() => toggleExpand(iface.id)}
                  onExport={() => setExportIface(iface)}
                />
              ))
            )}
          </Card>

          {/* RouterOS reference */}
          <Card>
            <CardContent className="px-5 py-4">
              <p className="text-xs font-medium text-muted-foreground mb-3">
                RouterOS 7 · /interface wireguard — быстрые команды
              </p>
              <div className="grid grid-cols-1 sm:grid-cols-3 gap-4 text-xs font-mono">
                {[
                  {
                    title: "Создать интерфейс",
                    lines: [
                      "/interface wireguard add \\",
                      "  name=wg0 \\",
                      "  listen-port=13231 \\",
                      "  mtu=1420",
                    ],
                  },
                  {
                    title: "Добавить пира",
                    lines: [
                      "/interface wireguard peers add \\",
                      "  interface=wg0 \\",
                      '  public-key="<ключ>" \\',
                      "  allowed-address=10.0.0.2/32 \\",
                      "  endpoint-address=1.2.3.4 \\",
                      "  persistent-keepalive=25",
                    ],
                  },
                  {
                    title: "Назначить IP",
                    lines: [
                      "/ip address add \\",
                      "  address=10.210.0.1/30 \\",
                      "  interface=wg0",
                      "",
                      "# Статус:",
                      "/interface wireguard print",
                    ],
                  },
                ].map((b) => (
                  <div key={b.title}>
                    <p className="font-sans font-semibold text-foreground/80 mb-1.5 text-[11px] uppercase tracking-wide">{b.title}</p>
                    <pre className="bg-zinc-950 rounded-md p-2.5 text-zinc-300 text-[11px] leading-relaxed overflow-x-auto">
                      {b.lines.join("\n")}
                    </pre>
                  </div>
                ))}
              </div>
            </CardContent>
          </Card>

        </div>
      </div>

      <ExportSheet
        open={!!exportIface}
        iface={exportIface}
        onClose={() => setExportIface(null)}
      />
    </div>
  )
}