"use client"

import { useState } from "react"
import type { WireGuardPeer } from "@/lib/data"
import { cn } from "@/lib/utils"
import { Button } from "@/components/ui/button"
import {
  ArrowDownIcon,
  ArrowUpIcon,
  CodeXmlIcon,
  KeyRoundIcon,
  Trash2Icon,
} from "lucide-react"

function fmtBytes(n: number | undefined): string {
  if (n === undefined || !Number.isFinite(n) || n < 0) 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)}`
}

function peerKey(peer: WireGuardPeer, index: number): string {
  return peer.id ?? peer.rosId ?? peer.publicKey ?? String(index)
}

function WireGuardPeersDetail({
  peers,
  interfaceName,
  onDeletePeer,
  onExportPeer,
}: {
  peers: WireGuardPeer[]
  interfaceName: string
  onDeletePeer?: (peerId: string) => void
  onExportPeer?: (peerId: string) => void
}) {
  const [page, setPage] = useState(0)
  const lastPage = Math.max(0, Math.ceil(peers.length / 50) - 1)
  const currentPage = Math.min(page, lastPage)
  const offset = currentPage * 50
  if (page > lastPage) setPage(lastPage)
  if (peers.length === 0) {
    return (
      <div className="px-5 py-4 text-xs text-muted-foreground text-center border-t border-border/50">
        Нет пиров
      </div>
    )
  }

  return (
    <section aria-label={"Пиры: " + interfaceName} className="sticky left-0 w-full max-w-[calc(100vw-2rem)] border-t border-border/50 md:max-w-none">
      <div className="flex flex-wrap items-center justify-between gap-2 px-4 py-2 bg-muted/10">
        <p className="text-xs text-muted-foreground" aria-live="polite">Пиры {offset + 1}–{Math.min(offset + 50, peers.length)} из {peers.length}</p>
        {peers.length > 50 && <div className="flex gap-1">
          <Button type="button" variant="outline" className="min-h-11" disabled={currentPage === 0} aria-label="Предыдущая страница пиров" onClick={() => setPage(currentPage - 1)}>Назад</Button>
          <Button type="button" variant="outline" className="min-h-11" disabled={currentPage >= lastPage} aria-label="Следующая страница пиров" onClick={() => setPage(currentPage + 1)}>Далее</Button>
        </div>}
      </div>
      {peers.slice(offset, offset + 50).map((peer, index) => {
        const id = peerKey(peer, offset + index)
        return (
          <div
            key={id}
            data-wireguard-peer={id}
            className="grid grid-cols-2 gap-3 px-4 py-3 items-center text-xs border-t border-border/50 bg-muted/20 md:grid-cols-[1fr_1fr_auto_auto_auto_auto]"
          >
            <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 break-all" title={peer.publicKey}>
                {peer.name || truncKey(peer.publicKey)}
              </span>
            </div>
            <div className="min-w-0 break-all font-mono text-muted-foreground">
              <span className="sr-only">Allowed IPs: </span><span>{peer.allowedIps.join(", ")}</span>
            </div>
            <span
              className={cn(
                "font-mono text-[11px] whitespace-nowrap",
                "text-muted-foreground",
              )}
            >
              <span className="sr-only">Последнее рукопожатие: </span><span>{peer.latestHandshake?.trim() || "Нет данных"}</span>
            </span>
            <div className="flex items-center gap-2 text-muted-foreground whitespace-nowrap">
              <span aria-label="RX" className="flex items-center gap-0.5">
                <ArrowDownIcon aria-hidden="true" className="size-3 text-success" />
                {fmtBytes(peer.transferRx)}
              </span>
              <span aria-label="TX" className="flex items-center gap-0.5">
                <ArrowUpIcon aria-hidden="true" className="size-3 text-info" />
                {fmtBytes(peer.transferTx)}
              </span>
            </div>
            <span className="min-w-0 break-all font-mono text-muted-foreground/60 text-[11px]"><span>Endpoint: </span>{peer.endpoint ?? "—"}</span>
            <div className="flex items-center gap-1 justify-end">
              {onExportPeer && (
                <Button
                  type="button"
                  variant="ghost"
                  size="icon"
                  className="size-11"
                  aria-label="Экспорт peer .conf"
                  onClick={(e) => {
                    e.stopPropagation()
                    onExportPeer(id)
                  }}
                >
                  <CodeXmlIcon className="size-3.5" />
                </Button>
              )}
              {onDeletePeer && (
                <Button
                  type="button"
                  variant="ghost"
                  size="icon"
                  className="size-11 text-destructive"
                  aria-label="Удалить пира"
                  onClick={(e) => {
                    e.stopPropagation()
                    onDeletePeer(id)
                  }}
                >
                  <Trash2Icon className="size-3.5" />
                </Button>
              )}
            </div>
          </div>
        )
      })}
    </section>
  )
}

export { WireGuardPeersDetail, fmtBytes, truncKey }