import { useEffect, useMemo, useState } from 'react'
import { Link2Icon, PlusIcon, Trash2Icon } from 'lucide-react'
import { ConfirmDialog } from '@/components/confirm-dialog'
import { EmptyState } from '@/components/empty-state'
import { TaggedInput, isValidIpv4 } from '@/components/tagged-input'
import { ServiceBindingIpInput } from '@/components/service-binding-ip-input'
import {
  HealthCheckConfigFields,
  type LbAndHealthConfig,
  type LbMode,
  type HealthCheckType,
} from '@/components/health-check-config-fields'
import type {
  CreateServiceWithConfigInput,
  DomainListItem,
  ServiceGroupView,
  ServiceView,
  UpdateServiceConfigInput,
} from '@/lib/schemas'
import { bindingToFqdn } from '@/lib/parse-fqdn'
import { AppButton } from '@/components/app-button'
import { AppInput } from '@/components/app-input'
import {
  AppField,
  AppFieldGroup,
  AppFieldLabel,
} from '@/components/app-field'
import {
  AppItem,
  AppItemActions,
  AppItemContent,
  AppItemGroup,
} from '@/components/app-item'
import { AppSeparator } from '@/components/app-separator'
import {
  Sheet,
  SheetContent,
  SheetDescription,
  SheetFooter,
  SheetHeader,
  SheetTitle,
} from '@cfdm/ui/components/sheet'
import { LoadingButton } from '@/components/loading-button'
import {
  Tabs,
  TabsContent,
  TabsList,
  TabsTrigger,
} from '@cfdm/ui/components/tabs'
import {
  Accordion,
  AccordionContent,
  AccordionItem,
  AccordionTrigger,
} from '@cfdm/ui/components/accordion'
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from '@cfdm/ui/components/select'
import { Separator } from '@cfdm/ui/components/separator'

interface BindingHealthConfig {
  enabled: boolean
  type: HealthCheckType
  port: number | null
  path: string | null
  expected_status: number | null
  interval_sec: number
  timeout_ms: number
}

export interface ServiceBindingDraft {
  fqdn: string
  record_type: 'A' | 'CNAME'
  target_ips: string[]
  target_cname: string
  lb_mode: LbMode
  health: BindingHealthConfig
  target_ip_weights: Record<string, number>
  target_ip_priorities: Record<string, number>
}

const defaultHealth: BindingHealthConfig = {
  enabled: false,
  type: 'tcp',
  port: null,
  path: null,
  expected_status: null,
  interval_sec: 30,
  timeout_ms: 3000,
}

interface ServiceEditSheetProps {
  mode: 'create' | 'edit'
  service: ServiceView | null
  groups: ServiceGroupView[]
  open: boolean
  knownDomains: DomainListItem[]
  isSaving: boolean
  isDeleting?: boolean
  defaultGroupId?: number | null
  onOpenChange: (open: boolean) => void
  onCreate?: (body: CreateServiceWithConfigInput) => void
  onSave?: (id: number, body: UpdateServiceConfigInput) => void
  onDelete?: (id: number) => void
}

function toBindingDrafts(service: ServiceView): ServiceBindingDraft[] {
  return (service.domains ?? []).map((binding) => ({
    fqdn: bindingToFqdn(binding),
    record_type: binding.record_type ?? (binding.target_cname ? 'CNAME' : 'A'),
    target_ips: binding.target_ips ?? [],
    target_cname: binding.target_cname ?? '',
    lb_mode: binding.lb_mode,
    health: {
      enabled: binding.health_check_enabled,
      type: binding.health_check_type,
      port: binding.health_check_port,
      path: binding.health_check_path,
      expected_status: binding.health_check_expected_status,
      interval_sec: binding.health_check_interval_sec,
      timeout_ms: binding.health_check_timeout_ms,
    },
    target_ip_weights: binding.target_ip_weights ?? {},
    target_ip_priorities: binding.target_ip_priorities ?? {},
  }))
}

function buildDomainsPayload(bindings: ServiceBindingDraft[]) {
  return bindings
    .filter((binding) => {
      if (!binding.fqdn.trim()) return false
      if (binding.record_type === 'CNAME') return Boolean(binding.target_cname.trim())
      return binding.target_ips.length > 0
    })
    .map((binding) =>
      binding.record_type === 'CNAME'
        ? {
            fqdn: binding.fqdn.trim(),
            target_cname: binding.target_cname.trim(),
            lb_mode: binding.lb_mode,
            health_check_enabled: binding.health.enabled,
            health_check_type: binding.health.type,
            health_check_port: binding.health.port,
            health_check_path: binding.health.path,
            health_check_expected_status: binding.health.expected_status,
            health_check_interval_sec: binding.health.interval_sec,
            health_check_timeout_ms: binding.health.timeout_ms,
          }
        : {
            fqdn: binding.fqdn.trim(),
            target_ips: binding.target_ips,
            target_ip_weights: binding.target_ip_weights,
            target_ip_priorities: binding.target_ip_priorities,
            lb_mode: binding.lb_mode,
            health_check_enabled: binding.health.enabled,
            health_check_type: binding.health.type,
            health_check_port: binding.health.port,
            health_check_path: binding.health.path,
            health_check_expected_status: binding.health.expected_status,
            health_check_interval_sec: binding.health.interval_sec,
            health_check_timeout_ms: binding.health.timeout_ms,
          },
    )
}

export function ServiceEditSheet({
  mode,
  service,
  groups,
  open,
  knownDomains,
  isSaving,
  isDeleting = false,
  defaultGroupId = null,
  onOpenChange,
  onCreate,
  onSave,
  onDelete,
}: ServiceEditSheetProps) {
  const [name, setName] = useState('')
  const [slug, setSlug] = useState('')
  const [serviceGroupId, setServiceGroupId] = useState('none')
  const [ips, setIps] = useState<string[]>([])
  const [bindings, setBindings] = useState<ServiceBindingDraft[]>([])
  const [lbWeight, setLbWeight] = useState(1)
  const [lbPriority, setLbPriority] = useState(1)

  const groupItems = useMemo(
    () => [
      { label: 'Без группы', value: 'none' },
      ...groups.map((group) => ({ label: group.name, value: String(group.id) })),
    ],
    [groups],
  )

  const selectedGroup = useMemo(() => {
    if (serviceGroupId === 'none') return null
    return groups.find((g) => String(g.id) === serviceGroupId) ?? null
  }, [groups, serviceGroupId])

  const groupHasDomain = Boolean(selectedGroup?.domain?.trim())

  useEffect(() => {
    if (!open) return
    if (mode === 'edit' && service) {
      setName(service.name)
      setSlug(service.slug)
      setServiceGroupId(
        service.service_group_id != null ? String(service.service_group_id) : 'none',
      )
      setIps(service.ips ?? [])
      setBindings(toBindingDrafts(service))
      setLbWeight(service.lb_weight ?? 1)
      setLbPriority(service.lb_priority ?? 1)
      return
    }
    if (mode === 'create') {
      setName('')
      setSlug('')
      setServiceGroupId(
        defaultGroupId != null ? String(defaultGroupId) : 'none',
      )
      setIps([])
      setBindings([])
      setLbWeight(1)
      setLbPriority(1)
    }
  }, [open, mode, service, defaultGroupId])

  const zoneHints = useMemo(
    () => knownDomains.map((domain) => domain.zone_name),
    [knownDomains],
  )

  function handleAddBinding() {
    setBindings((current) => [
      ...current,
      {
        fqdn: '',
        record_type: 'A',
        target_ips: [],
        target_cname: '',
        lb_mode: 'round_robin',
        health: { ...defaultHealth },
        target_ip_weights: {},
        target_ip_priorities: {},
      },
    ])
  }

  function handleRemoveBinding(index: number) {
    setBindings((current) => current.filter((_, i) => i !== index))
  }

  function handleFqdnChange(index: number, tags: string[]) {
    const fqdn = tags[0] ?? ''
    setBindings((current) =>
      current.map((item, i) => (i === index ? { ...item, fqdn } : item)),
    )
  }

  function handleRecordTypeChange(index: number, recordType: 'A' | 'CNAME') {
    setBindings((current) =>
      current.map((item, i) =>
        i === index
          ? {
              ...item,
              record_type: recordType,
              target_ips: recordType === 'A' ? item.target_ips : [],
              target_cname: recordType === 'CNAME' ? item.target_cname : '',
            }
          : item,
      ),
    )
  }

  function handleCnameChange(index: number, value: string) {
    setBindings((current) =>
      current.map((item, i) => (i === index ? { ...item, target_cname: value } : item)),
    )
  }

  function handleIpsChange(index: number, targetIps: string[]) {
    setBindings((current) =>
      current.map((item, i) =>
        i === index
          ? {
              ...item,
              target_ips: targetIps,
              target_ip_weights: Object.fromEntries(
                targetIps.map((ip) => [ip, item.target_ip_weights[ip] ?? 1]),
              ),
              target_ip_priorities: Object.fromEntries(
                targetIps.map((ip) => [ip, item.target_ip_priorities[ip] ?? 1]),
              ),
            }
          : item,
      ),
    )
  }

  function handleBindingMetaChange(
    index: number,
    ip: string,
    meta: { weight?: number; priority?: number },
  ) {
    setBindings((current) =>
      current.map((item, i) => {
        if (i !== index) return item
        const weights = { ...item.target_ip_weights }
        const priorities = { ...item.target_ip_priorities }
        if (meta.weight !== undefined) weights[ip] = meta.weight
        if (meta.priority !== undefined) priorities[ip] = meta.priority
        return { ...item, target_ip_weights: weights, target_ip_priorities: priorities }
      }),
    )
  }

  function handleBindingHealthChange(index: number, next: LbAndHealthConfig) {
    setBindings((current) =>
      current.map((item, i) =>
        i === index
          ? {
              ...item,
              lb_mode: next.lb_mode,
              health: {
                enabled: next.enabled,
                type: next.type,
                port: next.port,
                path: next.path,
                expected_status: next.expected_status,
                interval_sec: next.interval_sec,
                timeout_ms: next.timeout_ms,
              },
            }
          : item,
      ),
    )
  }

  function resolveServiceGroupId(): number | null {
    return serviceGroupId === 'none' ? null : Number(serviceGroupId)
  }

  function handleSubmit() {
    const domains = buildDomainsPayload(bindings)
    const groupId = resolveServiceGroupId()
    const lbFields = groupHasDomain
      ? { lb_weight: lbWeight, lb_priority: lbPriority }
      : {}
    const configPayload = {
      ips,
      ...lbFields,
      ...(domains.length > 0 ? { domains } : {}),
    }
    if (mode === 'create') {
      onCreate?.({
        name: name.trim(),
        slug: slug.trim(),
        service_group_id: groupId,
        ips,
        ...lbFields,
        domains,
      })
      return
    }
    if (!service) return
    onSave?.(service.id, {
      name,
      slug,
      service_group_id: groupId,
      ...configPayload,
    })
  }

  function handleDelete() {
    if (!service) return
    onDelete?.(service.id)
  }

  const isCreate = mode === 'create'
  const canSubmit = isCreate
    ? name.trim().length > 0 && slug.trim().length > 0
    : Boolean(service)

  return (
    <Sheet open={open} onOpenChange={onOpenChange}>
      <SheetContent className="flex w-full flex-col gap-0 overflow-y-auto sm:max-w-xl">
        <SheetHeader className="border-b pb-4">
          <SheetTitle>{isCreate ? 'Новый сервис' : 'Редактирование сервиса'}</SheetTitle>
          <SheetDescription>
            Настройте параметры сервиса и привязки FQDN → IP или CNAME. Зона определяется из FQDN
            автоматически.
          </SheetDescription>
        </SheetHeader>

        <div className="flex flex-1 flex-col gap-4 px-4 py-4">
          <Tabs
            defaultValue="general"
            orientation="horizontal"
            className="flex w-full flex-col gap-4"
          >
            <TabsList variant="line" className="w-full gap-5">
              <TabsTrigger value="general" className="px-0 pb-2">
                Основное
              </TabsTrigger>
              <TabsTrigger value="bindings" className="gap-2 px-0 pb-2">
                Привязки
                {bindings.length > 0 ? (
                  <span className="bg-muted text-muted-foreground inline-flex min-w-5 items-center justify-center rounded-md px-1.5 py-0.5 text-xs tabular-nums">
                    {bindings.length}
                  </span>
                ) : null}
              </TabsTrigger>
            </TabsList>

            <TabsContent value="general" className="flex flex-col gap-4">
              <AppFieldGroup className="flex flex-col gap-4">
                <AppField>
                  <AppFieldLabel htmlFor="edit-service-name">Название</AppFieldLabel>
                  <AppInput
                    id="edit-service-name"
                    value={name}
                    placeholder={isCreate ? 'VPN Panel' : undefined}
                    onChange={(e) => setName(e.target.value)}
                  />
                </AppField>
                <AppField>
                  <AppFieldLabel htmlFor="edit-service-slug">Slug</AppFieldLabel>
                  <AppInput
                    id="edit-service-slug"
                    value={slug}
                    placeholder={isCreate ? 'vpn-panel' : undefined}
                    onChange={(e) => setSlug(e.target.value)}
                  />
                </AppField>
                <AppField>
                  <AppFieldLabel htmlFor="edit-service-group">Группа сервисов</AppFieldLabel>
                  <Select
                    items={groupItems}
                    value={serviceGroupId}
                    onValueChange={(value) => setServiceGroupId(value ?? 'none')}
                  >
                    <SelectTrigger id="edit-service-group" className="w-full">
                      <SelectValue placeholder="Без группы" />
                    </SelectTrigger>
                    <SelectContent>
                      {groupItems.map((item) => (
                        <SelectItem key={item.value} value={item.value}>
                          {item.label}
                        </SelectItem>
                      ))}
                    </SelectContent>
                  </Select>
                </AppField>
                <AppField>
                  <AppFieldLabel htmlFor="edit-service-ips">IP-адреса сервиса</AppFieldLabel>
                  <TaggedInput
                    id="edit-service-ips"
                    value={ips}
                    onChange={setIps}
                    placeholder="192.168.1.1"
                    validate={isValidIpv4}
                  />
                </AppField>
              </AppFieldGroup>

              {groupHasDomain && (
                <>
                  <Separator />
                  <div className="flex flex-col gap-2">
                    <p className="text-sm text-muted-foreground">
                      Балансировка внутри группы «{selectedGroup?.name}»: вес и приоритет
                      сервиса для общего домена группы.
                    </p>
                    <div className="grid grid-cols-2 gap-4">
                      <AppField>
                        <AppFieldLabel htmlFor="service-lb-weight">Вес</AppFieldLabel>
                        <AppInput
                          id="service-lb-weight"
                          type="number"
                          inputMode="numeric"
                          min={1}
                          max={100}
                          value={lbWeight}
                          onChange={(e) =>
                            setLbWeight(Math.max(1, Number(e.target.value) || 1))
                          }
                        />
                      </AppField>
                      <AppField>
                        <AppFieldLabel htmlFor="service-lb-priority">Приоритет</AppFieldLabel>
                        <AppInput
                          id="service-lb-priority"
                          type="number"
                          inputMode="numeric"
                          min={1}
                          max={100}
                          value={lbPriority}
                          onChange={(e) =>
                            setLbPriority(Math.max(1, Number(e.target.value) || 1))
                          }
                        />
                      </AppField>
                    </div>
                  </div>
                </>
              )}
            </TabsContent>

            <TabsContent value="bindings" className="flex flex-col gap-4">
              <div className="flex items-center justify-between gap-2">
                <p className="text-sm text-muted-foreground">
                  FQDN → IP или CNAME для DNS-записей Cloudflare
                </p>
                <AppButton type="button" variant="outline" size="sm" onClick={handleAddBinding}>
                  <PlusIcon data-icon="inline-start" />
                  Добавить
                </AppButton>
              </div>

              {bindings.length === 0 ? (
                <EmptyState
                  icon={Link2Icon}
                  title="Нет привязок"
                  description="Необязательно. Пример: newdom.ivx.su — зона ivx.su определится автоматически."
                  action={
                    <AppButton type="button" variant="outline" size="sm" onClick={handleAddBinding}>
                      <PlusIcon data-icon="inline-start" />
                      Добавить привязку
                    </AppButton>
                  }
                />
              ) : (
                <AppItemGroup className="gap-2">
                  {bindings.map((binding, index) => {
                    const showLbBlock =
                      (binding.record_type === 'A' && binding.target_ips.length > 0) ||
                      (binding.record_type === 'CNAME' && binding.target_cname.trim().length > 0)
                    const showMeta =
                      binding.record_type === 'A' &&
                      binding.target_ips.length > 1 &&
                      binding.lb_mode !== 'round_robin'
                    return (
                      <AppItem key={`binding-${index}`} variant="outline">
                        <AppItemContent className="flex flex-col gap-3">
                          <AppField>
                            <AppFieldLabel htmlFor={`binding-fqdn-${index}`}>FQDN</AppFieldLabel>
                            <TaggedInput
                              id={`binding-fqdn-${index}`}
                              value={binding.fqdn ? [binding.fqdn] : []}
                              onChange={(tags) => handleFqdnChange(index, tags)}
                              placeholder={
                                zoneHints[0] ? `newdom.${zoneHints[0]}` : 'newdom.ivx.su'
                              }
                              maxItems={1}
                            />
                          </AppField>
                          <AppField>
                            <AppFieldLabel htmlFor={`binding-type-${index}`}>Тип записи</AppFieldLabel>
                            <Select
                              items={[
                                { label: 'A (IP)', value: 'A' },
                                { label: 'CNAME', value: 'CNAME' },
                              ]}
                              value={binding.record_type}
                              onValueChange={(value) =>
                                handleRecordTypeChange(index, (value ?? 'A') as 'A' | 'CNAME')
                              }
                            >
                              <SelectTrigger id={`binding-type-${index}`} className="w-full">
                                <SelectValue />
                              </SelectTrigger>
                              <SelectContent>
                                <SelectItem value="A">A (IP)</SelectItem>
                                <SelectItem value="CNAME">CNAME</SelectItem>
                              </SelectContent>
                            </Select>
                          </AppField>
                          {binding.record_type === 'CNAME' ? (
                            <AppField>
                              <AppFieldLabel htmlFor={`binding-cname-${index}`}>
                                CNAME-цель
                              </AppFieldLabel>
                              <AppInput
                                id={`binding-cname-${index}`}
                                value={binding.target_cname}
                                placeholder="mmsk.rkns.top"
                                onChange={(event) => handleCnameChange(index, event.target.value)}
                              />
                            </AppField>
                          ) : (
                            <AppField>
                              <AppFieldLabel htmlFor={`binding-ip-${index}`}>IP</AppFieldLabel>
                              <ServiceBindingIpInput
                                id={`binding-ip-${index}`}
                                value={binding.target_ips}
                                pool={ips}
                                onChange={(targetIps) => handleIpsChange(index, targetIps)}
                                showMeta={showLbBlock && showMeta}
                                weights={binding.target_ip_weights}
                                priorities={binding.target_ip_priorities}
                                onMetaChange={(ip, meta) =>
                                  handleBindingMetaChange(index, ip, meta)
                                }
                              />
                            </AppField>
                          )}

                          {showLbBlock && (
                            <Accordion defaultValue={[`lb-${index}`]}>
                              <AccordionItem value={`lb-${index}`}>
                                <AccordionTrigger>
                                  {binding.record_type === 'CNAME'
                                    ? 'Health-check'
                                    : binding.target_ips.length > 1
                                      ? 'Балансировка и Health-check (multi-A)'
                                      : 'Health-check'}
                                </AccordionTrigger>
                                <AccordionContent>
                                  <HealthCheckConfigFields
                                    value={{
                                      lb_mode: binding.lb_mode,
                                      enabled: binding.health.enabled,
                                      type: binding.health.type,
                                      port: binding.health.port,
                                      path: binding.health.path,
                                      expected_status: binding.health.expected_status,
                                      interval_sec: binding.health.interval_sec,
                                      timeout_ms: binding.health.timeout_ms,
                                    }}
                                    onChange={(next) =>
                                      handleBindingHealthChange(index, next)
                                    }
                                    lbModeLabel="Режим балансировки"
                                    showLbMode={
                                      binding.record_type === 'A' &&
                                      binding.target_ips.length > 1
                                    }
                                    idPrefix={`binding-${index}-health`}
                                  />
                                </AccordionContent>
                              </AccordionItem>
                            </Accordion>
                          )}
                        </AppItemContent>
                        <AppItemActions>
                          <AppButton
                            type="button"
                            variant="ghost"
                            size="icon-sm"
                            aria-label="Удалить привязку"
                            onClick={() => handleRemoveBinding(index)}
                          >
                            <Trash2Icon />
                          </AppButton>
                        </AppItemActions>
                      </AppItem>
                    )
                  })}
                </AppItemGroup>
              )}
            </TabsContent>
          </Tabs>
        </div>

        <AppSeparator />

        <SheetFooter className="flex flex-row flex-wrap gap-2 border-t-0 pt-4">
          {!isCreate ? (
            <ConfirmDialog
              trigger={
                <LoadingButton
                  type="button"
                  variant="destructive"
                  disabled={!service || isDeleting || isSaving}
                  isLoading={isDeleting}
                  loadingLabel="Удаление…"
                >
                  <Trash2Icon data-icon="inline-start" />
                  Удалить
                </LoadingButton>
              }
              title="Удалить сервис?"
              description="Сервис и связанные DNS-привязки будут удалены. Действие необратимо."
              onConfirm={handleDelete}
            />
          ) : null}
          <LoadingButton
            type="button"
            className="ml-auto"
            disabled={!canSubmit || isDeleting}
            isLoading={isSaving}
            loadingLabel="Сохранение…"
            onClick={handleSubmit}
          >
            {isCreate ? 'Создать' : 'Сохранить'}
          </LoadingButton>
        </SheetFooter>
      </SheetContent>
    </Sheet>
  )
}