stalniy/casl

import { SubjectType, AbilityTypes, AbilityTupleType, Abilities, ToAbilityTypes } from './types';

interface BaseRawRule<Conditions> {
  fields?: string | string[]
  conditions?: Conditions
  /** indicates that rule forbids something (i.e., has inverted logic) */
  inverted?: boolean
  /** explains the reason of why rule does not allow to do something */
  reason?: string
}

export interface ClaimRawRule<A extends string> extends BaseRawRule<undefined> {
  action: A | A[]
  subject?: undefined
}

export interface SubjectRawRule<A extends string, S extends SubjectType, C> extends BaseRawRule<C> {
  action: A | A[]
  subject: S | S[]
}

type DefineRule<T extends AbilityTypes, C, Else = ClaimRawRule<Extract<T, string>>> =
  T extends AbilityTupleType ? SubjectRawRule<T[0], T[1], C> : Else;

export type RawRule<T extends AbilityTypes = AbilityTupleType, C = unknown> = DefineRule<T, C>;
export type RawRuleFrom<T extends Abilities, C> = RawRule<ToAbilityTypes<T>, C>;