"use client"

import { useEffect, useMemo, useState } from "react"
import { FormField, FormToggle, SectionTitle } from "@/components/form-kit"
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 { Alert, AlertDescription, AlertTitle } from "@/components/reui/alert"
import { InfoIcon } from "lucide-react"

export type IpsecInitFormState = {
  serverId: string
  serverEndpoint: string
  poolCidr: string
  dns: string
  createNatRule: boolean
}

export const defaultIpsecInitForm = (): IpsecInitFormState => ({
  serverId: "",
  serverEndpoint: "",
  poolCidr: "10.77.0.0/24",
  dns: "",
  createNatRule: true,
})

type ServerOption = { id: string; name: string; host: string }

function IpsecInitSheet({
  open,
  onOpenChange,
  servers,
  busy,
  defaultServerId,
  onSubmit,
}: {
  open: boolean
  onOpenChange: (v: boolean) => void
  servers: ServerOption[]
  busy?: boolean
  defaultServerId?: string
  onSubmit: (form: IpsecInitFormState) => void | Promise<void>
}) {
  const [form, setForm] = useState<IpsecInitFormState>(defaultIpsecInitForm)
  const set = <K extends keyof IpsecInitFormState>(k: K, v: IpsecInitFormState[K]) =>
    setForm((f) => ({ ...f, [k]: v }))

  useEffect(() => {
    if (!open) return
    const server = servers.find((s) => s.id === (defaultServerId ?? ""))
    queueMicrotask(() => setForm({
      ...defaultIpsecInitForm(),
      serverId: defaultServerId ?? "",
      serverEndpoint: server?.host ?? "",
    }))
  }, [open, defaultServerId, servers])

  const canSubmit = useMemo(() => {
    return Boolean(
      form.serverId &&
      form.serverEndpoint.trim() &&
      /^(\d{1,3}(?:\.\d{1,3}){3}\/\d{1,2}|[\w.-]+\.[a-z]{2,})$/i.test(form.serverEndpoint.trim()) &&
      /^\d{1,3}(?:\.\d{1,3}){3}\/\d{1,2}$/.test(form.poolCidr.trim()),
    )
  }, [form])

  return (
    <Sheet open={open} onOpenChange={onOpenChange}>
      <SheetContent side="right" className="w-full sm:max-w-md flex flex-col gap-0 p-0">
        <SheetHeader className="px-6 pt-6 pb-4 border-b shrink-0">
          <SheetTitle>Инициализация IKEv2-сервера</SheetTitle>
          <SheetDescription>
            CA + серверный сертификат, peer (ike2/passive), пул адресов и mode-config
          </SheetDescription>
        </SheetHeader>

        <div className="flex-1 overflow-y-auto px-6 py-5 flex flex-col gap-5">
          <Alert variant="info">
            <InfoIcon />
            <AlertTitle>Выпуск CA и сертификатов занимает до минуты</AlertTitle>
            <AlertDescription>
              Повторный запуск безопасен: существующие managed-объекты обновятся, сертификаты
              не перевыпускаются.
            </AlertDescription>
          </Alert>

          <div className="flex flex-col gap-4">
            <SectionTitle>Основные</SectionTitle>
            <FormField label="Сервер" required>
              <select
                className="flex h-9 w-full rounded-md border border-input bg-transparent px-3 py-1 text-sm shadow-xs outline-none focus-visible:border-ring focus-visible:ring-ring/50 focus-visible:ring-[3px]"
                value={form.serverId}
                onChange={(e) => {
                  const id = e.target.value
                  const server = servers.find((s) => s.id === id)
                  setForm((f) => ({ ...f, serverId: id, serverEndpoint: server?.host ?? f.serverEndpoint }))
                }}
              >
                <option value="">Выберите сервер…</option>
                {servers.map((s) => (
                  <option key={s.id} value={s.id}>
                    {s.name} ({s.host})
                  </option>
                ))}
              </select>
            </FormField>
            <FormField label="Адрес сервера (CN/SAN)" required hint="Домен или IP — по нему подключаются клиенты">
              <Input
                className="font-mono"
                placeholder="vpn.example.com"
                value={form.serverEndpoint}
                onChange={(e) => set("serverEndpoint", e.target.value)}
              />
            </FormField>
            <FormField label="Подсеть клиентов" required hint="Из неё пул .2–.254 и статические IP">
              <Input
                className="font-mono"
                placeholder="10.77.0.0/24"
                value={form.poolCidr}
                onChange={(e) => set("poolCidr", e.target.value)}
              />
            </FormField>
            <FormField label="DNS для клиентов" hint="Например 10.77.0.1 или 1.1.1.1">
              <Input
                className="font-mono"
                value={form.dns}
                onChange={(e) => set("dns", e.target.value)}
              />
            </FormField>
            <div className="flex items-center justify-between">
              <div>
                <p className="text-sm font-medium">Интернет клиентам (NAT)</p>
                <p className="text-xs text-muted-foreground">
                  Managed srcnat masquerade для подсети клиентов (out-interface-list WAN)
                </p>
              </div>
              <FormToggle checked={form.createNatRule} onChange={(v) => set("createNatRule", v)} />
            </div>
          </div>
        </div>

        <SheetFooter className="px-6 py-4 border-t shrink-0 flex-row gap-2">
          <SheetClose render={<Button variant="outline" className="flex-1" disabled={busy} />}>
            Отмена
          </SheetClose>
          <Button
            className="flex-1"
            disabled={!canSubmit || busy}
            onClick={() => void onSubmit(form)}
          >
            {busy ? "Инициализация…" : "Инициализировать"}
          </Button>
        </SheetFooter>
      </SheetContent>
    </Sheet>
  )
}

export { IpsecInitSheet }