import { map, Subject, type Observable } from 'rxjs'

import type { OrchModel } from '../model'
import { epic } from './epic'
import { Performer } from './performer'

export type SignalFactory<P, R> = (payload$: Observable<P>) => Observable<R>

export type SignalPerformer<P, R> = Performer<P, void> & { signal$: Observable<R> }

export function signal<P = void, R = P>(
  model: OrchModel<any>,
  factory?: SignalFactory<P, R>,
): SignalPerformer<P, R>
export function signal(
  model: OrchModel<any>,
  factory?: SignalFactory<any, any>,
): SignalPerformer<any, any> {
  const signalSource = new Subject()

  return Object.assign(
    epic(
      model,
      ({ payload$, action }) =>
        (factory ? factory(payload$) : payload$).pipe(
          map((value) => action(() => signalSource.next(value))),
        ),
      {
        factoryToLog: factory,
      },
    ),
    { signal$: signalSource.asObservable() },
  )
}