'use client'

import { useEffect, useState } from 'react'
import { type DefaultValues, type FieldValues, type Resolver, useForm, type UseFormReturn } from 'react-hook-form'

import { addToast } from '@/lib/toast'
import type { ServiceResult } from '@/services/errorHandler'

interface UseAdminCrudFormModalOptions<TEntity, TFormValues extends FieldValues, TPayload, TId> {
  /** Present when editing; absent (undefined) when creating a new entity. */
  entity: TEntity | undefined
  isOpen: boolean
  emptyValues: TFormValues
  toFormValues: (entity: TEntity) => TFormValues
  resolver: Resolver<TFormValues>
  buildPayload: (values: TFormValues) => TPayload
  create: (payload: TPayload) => Promise<ServiceResult<unknown>>
  update: (id: TId, payload: TPayload) => Promise<ServiceResult<unknown>>
  getId: (entity: TEntity) => TId
  successMessage: { create: string; edit: string }
  onOpenChange: (isOpen: boolean) => void
  onSuccess: () => void
}

interface UseAdminCrudFormModalResult<TFormValues extends FieldValues> {
  form: UseFormReturn<TFormValues>
  isEdit: boolean
  submitting: boolean
  // react-hook-form's form.handleSubmit(...) is Promise-returning, not
  // void — declaring void here would be a lying type that trips
  // @typescript-eslint/no-misused-promises at the return statement below.
  handleSubmit: () => Promise<void>
}

/**
 * Owns the repeated *shape* behind the admin create/edit form modals (tags,
 * event categories, blog articles, …): a reset-on-open effect plus a
 * submitting-flag/create-or-update/toast/close/refresh submit flow. Each
 * modal keeps its own field set (`emptyValues`, `toFormValues`) and payload
 * shape (`buildPayload`) — this hook never inspects either.
 */
export default function useAdminCrudFormModal<TEntity, TFormValues extends FieldValues, TPayload, TId>({
  entity,
  isOpen,
  emptyValues,
  toFormValues,
  resolver,
  buildPayload,
  create,
  update,
  getId,
  successMessage,
  onOpenChange,
  onSuccess,
}: UseAdminCrudFormModalOptions<TEntity, TFormValues, TPayload, TId>): UseAdminCrudFormModalResult<TFormValues> {
  const isEdit = Boolean(entity)
  const [submitting, setSubmitting] = useState(false)

  const form = useForm<TFormValues>({
    resolver,
    defaultValues: (entity ? toFormValues(entity) : emptyValues) as DefaultValues<TFormValues>,
  })
  const { reset } = form

  // Modal instance is reused across opens, so form state needs an explicit
  // reset whenever the target entity changes or the modal re-opens.
  useEffect(() => {
    if (isOpen) {
      reset(entity ? toFormValues(entity) : emptyValues)
    }
  }, [entity, isOpen, reset, toFormValues, emptyValues])

  const onSubmit = async (values: TFormValues) => {
    setSubmitting(true)

    const payload = buildPayload(values)
    const result = isEdit && entity ? await update(getId(entity), payload) : await create(payload)

    setSubmitting(false)

    if (!result.ok) return

    addToast({ title: isEdit ? successMessage.edit : successMessage.create, color: 'success' })
    onOpenChange(false)
    onSuccess()
  }

  return { form, isEdit, submitting, handleSubmit: form.handleSubmit(onSubmit) }
}