import { Injectable, inject, signal } from '@angular/core'
import { FormApi } from '@tanstack/form-core'
import type {
  FormAsyncValidateOrFn,
  FormOptions,
  FormValidateOrFn,
} from '@tanstack/form-core'

@Injectable({ providedIn: null })
export class TanStackWithFormInjectable {
  _form = signal<
    FormApi<any, any, any, any, any, any, any, any, any, any, any, any>
  >(null as never)
}

interface TanStackWithFormRef<
  TFormData,
  TOnMount extends undefined | FormValidateOrFn<TFormData>,
  TOnChange extends undefined | FormValidateOrFn<TFormData>,
  TOnChangeAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnBlur extends undefined | FormValidateOrFn<TFormData>,
  TOnBlurAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnSubmit extends undefined | FormValidateOrFn<TFormData>,
  TOnSubmitAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnDynamic extends undefined | FormValidateOrFn<TFormData>,
  TOnDynamicAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnServer extends undefined | FormAsyncValidateOrFn<TFormData>,
  TSubmitMeta,
> {
  readonly form: FormApi<
    TFormData,
    TOnMount,
    TOnChange,
    TOnChangeAsync,
    TOnBlur,
    TOnBlurAsync,
    TOnSubmit,
    TOnSubmitAsync,
    TOnDynamic,
    TOnDynamicAsync,
    TOnServer,
    TSubmitMeta
  >
}

/**
 * Injects the form provided by an ancestor `[tanstack-with-form]` directive.
 *
 * Pass form options (typically the same options used to create the form) so
 * the returned `form` is typed correctly without needing to specify generics:
 *
 * ```ts
 * const withForm = injectWithForm({ ...peopleFormOpts })
 * withForm.form // FormApi<PeopleFormData, ...>
 * ```
 *
 * The options are only used for type inference and are not read at runtime.
 */
export function injectWithForm<
  TFormData,
  TOnMount extends undefined | FormValidateOrFn<TFormData>,
  TOnChange extends undefined | FormValidateOrFn<TFormData>,
  TOnChangeAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnBlur extends undefined | FormValidateOrFn<TFormData>,
  TOnBlurAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnSubmit extends undefined | FormValidateOrFn<TFormData>,
  TOnSubmitAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnDynamic extends undefined | FormValidateOrFn<TFormData>,
  TOnDynamicAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnServer extends undefined | FormAsyncValidateOrFn<TFormData>,
  TSubmitMeta,
>(
  _opts?: FormOptions<
    TFormData,
    TOnMount,
    TOnChange,
    TOnChangeAsync,
    TOnBlur,
    TOnBlurAsync,
    TOnSubmit,
    TOnSubmitAsync,
    TOnDynamic,
    TOnDynamicAsync,
    TOnServer,
    TSubmitMeta
  >,
): TanStackWithFormRef<
  TFormData,
  TOnMount,
  TOnChange,
  TOnChangeAsync,
  TOnBlur,
  TOnBlurAsync,
  TOnSubmit,
  TOnSubmitAsync,
  TOnDynamic,
  TOnDynamicAsync,
  TOnServer,
  TSubmitMeta
> {
  const injectable = inject(TanStackWithFormInjectable)
  return {
    get form() {
      return injectable._form() as FormApi<
        TFormData,
        TOnMount,
        TOnChange,
        TOnChangeAsync,
        TOnBlur,
        TOnBlurAsync,
        TOnSubmit,
        TOnSubmitAsync,
        TOnDynamic,
        TOnDynamicAsync,
        TOnServer,
        TSubmitMeta
      >
    },
  }
}