"use client"

import { useEffect, useMemo, useState } from "react"
import type { IpsecClientDto } from "@mmapp/contracts/ipsec"
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"

export type IpsecAuthKind = "certificate" | "pre-shared-key"

export type IpsecUserFormState = {
  serverId: string
  name: string
  peerName: string
  authMethod: IpsecAuthKind
  psk: string
  remoteId: string
  useStaticIp: boolean
  staticIp: string
  passphrase: string
}

export const defaultIpsecUserForm = (): IpsecUserFormState => ({
  serverId: "",
  name: "",
  peerName: "",
  authMethod: "certificate",
  psk: "",
  remoteId: "",
  useStaticIp: false,
  staticIp: "",
  passphrase: "",
})

type ServerOption = { id: string; name: string; host: string }
export type PeerOption = { serverId: string; name: string; managed: boolean }

function IpsecUserSheet({
  open,
  onOpenChange,
  servers,
  peers,
  busy,
  defaultServerId,
  editing,
  freeIpHint,
  onSubmit,
}: {
  open: boolean
  onOpenChange: (v: boolean) => void
  servers: ServerOption[]
  /** Доступные peers (серверы) для привязки identity при создании. */
  peers?: PeerOption[]
  busy?: boolean
  defaultServerId?: string
  /** Режим редактирования: сервер и метод аутентификации не меняются. */
  editing?: IpsecClientDto | null
  freeIpHint?: string
  onSubmit: (form: IpsecUserFormState) => void | Promise<void>
}) {
  const [form, setForm] = useState<IpsecUserFormState>(defaultIpsecUserForm)
  const set = <K extends keyof IpsecUserFormState>(k: K, v: IpsecUserFormState[K]) =>
    setForm((f) => ({ ...f, [k]: v }))

  useEffect(() => {
    if (!open) return
    if (editing) {
      const edit = editing
      queueMicrotask(() => setForm({
        serverId: edit.serverId,
        name: edit.name,
        peerName: edit.peerName ?? "",
        authMethod: edit.authMethod,
        psk: "",
        remoteId: edit.remoteId ?? "",
        useStaticIp: Boolean(edit.staticIp),
        staticIp: edit.staticIp ?? "",
        passphrase: "",
      }))
      return
    }
    queueMicrotask(() => setForm({ ...defaultIpsecUserForm(), serverId: defaultServerId ?? "" }))
  }, [open, defaultServerId, editing])

  const canSubmit = useMemo(() => {
    if (!editing && !form.serverId) return false
    if (!form.name.trim()) return false
    if (!editing && form.authMethod === "pre-shared-key" && form.psk.trim().length < 8) return false
    if (form.useStaticIp && form.staticIp.trim() && !/^\d{1,3}(?:\.\d{1,3}){3}$/.test(form.staticIp.trim())) return false
    return true
  }, [form, editing])

  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>{editing ? `Клиент «${editing.name}»` : "Новый клиент IKEv2"}</SheetTitle>
          <SheetDescription>
            {editing
              ? "Имя, статический IP и secret (для PSK)"
              : "Identity на роутере; для сертификата — выпуск .p12 для авторизации"}
          </SheetDescription>
        </SheetHeader>

        <div className="flex-1 overflow-y-auto px-6 py-5 flex flex-col gap-5">
          <div className="flex flex-col gap-4">
            <SectionTitle>Основные</SectionTitle>
            {!editing ? (
              <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) => set("serverId", e.target.value)}
                >
                  <option value="">Выберите сервер…</option>
                  {servers.map((s) => (
                    <option key={s.id} value={s.id}>
                      {s.name} ({s.host})
                    </option>
                  ))}
                </select>
              </FormField>
            ) : null}
            {!editing && (peers ?? []).some((p) => p.serverId === form.serverId) ? (
              <FormField label="Peer (сервер)" hint="К какому peer привязать identity">
                <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.peerName}
                  onChange={(e) => set("peerName", e.target.value)}
                >
                  <option value="">Автоматически (managed/первый)</option>
                  {(peers ?? [])
                    .filter((p) => p.serverId === form.serverId)
                    .map((p) => (
                      <option key={`${p.serverId}:${p.name}`} value={p.name}>
                        {p.name}{p.managed ? "" : " (RouterOS)"}
                      </option>
                    ))}
                </select>
              </FormField>
            ) : null}
            <FormField label="Имя клиента" required hint={editing ? undefined : "CN сертификата и отображаемое имя"}>
              <Input
                placeholder="alice"
                value={form.name}
                onChange={(e) => set("name", e.target.value)}
              />
            </FormField>
            {!editing ? (
              <FormField label="Аутентификация" required>
                <div className="flex gap-1.5">
                  <Button
                    type="button"
                    size="sm"
                    variant={form.authMethod === "certificate" ? "secondary" : "ghost"}
                    onClick={() => set("authMethod", "certificate")}
                  >
                    Сертификат
                  </Button>
                  <Button
                    type="button"
                    size="sm"
                    variant={form.authMethod === "pre-shared-key" ? "secondary" : "ghost"}
                    onClick={() => set("authMethod", "pre-shared-key")}
                  >
                    PSK
                  </Button>
                </div>
              </FormField>
            ) : null}
            {form.authMethod === "pre-shared-key" ? (
              <>
                <FormField label={editing ? "Новый secret (PSK)" : "Secret (PSK)"} hint={editing ? "Пусто — не менять" : "Минимум 8 символов"} required={!editing}>
                  <Input
                    className="font-mono"
                    type="password"
                    value={form.psk}
                    onChange={(e) => set("psk", e.target.value)}
                  />
                </FormField>
                {!editing ? (
                  <FormField label="Remote ID" hint="По умолчанию — имя клиента">
                    <Input
                      className="font-mono"
                      placeholder="alice"
                      value={form.remoteId}
                      onChange={(e) => set("remoteId", e.target.value)}
                    />
                  </FormField>
                ) : null}
              </>
            ) : (
              !editing ? (
                <FormField label="Пароль архива .p12" hint="Пусто — сгенерируем автоматически">
                  <Input
                    className="font-mono"
                    placeholder="например MySecret123"
                    value={form.passphrase}
                    onChange={(e) => set("passphrase", e.target.value)}
                  />
                </FormField>
              ) : null
            )}
          </div>

          <div className="flex flex-col gap-4">
            <SectionTitle>IP-адрес</SectionTitle>
            <div className="flex items-center justify-between">
              <div>
                <p className="text-sm font-medium">Статический IP</p>
                <p className="text-xs text-muted-foreground">
                  {freeIpHint ? `Свободный из пула: ${freeIpHint}` : "Иначе — выдача из пула"}
                </p>
              </div>
              <FormToggle checked={form.useStaticIp} onChange={(v) => set("useStaticIp", v)} />
            </div>
            {form.useStaticIp && (
              <FormField label="IP клиента" hint="Например 10.77.0.10">
                <Input
                  className="font-mono"
                  placeholder={freeIpHint ?? "10.77.0.10"}
                  value={form.staticIp}
                  onChange={(e) => set("staticIp", e.target.value)}
                />
              </FormField>
            )}
          </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 ? (editing ? "Сохранение…" : "Создание…") : editing ? "Сохранить" : "Создать клиента"}
          </Button>
        </SheetFooter>
      </SheetContent>
    </Sheet>
  )
}

export { IpsecUserSheet }