import { OperatorFunction, pipe } from "rxjs";
import { filter } from "rxjs/operators";

interface Action {
  type: string;
}

export type GenerateIdFn = () => string | number;

export type ActionWithCorrelationId<T extends Action = Action> = T & {
  correlationId: string | number;
};

let id = 0;
function defaultGenerateId() {
  return id++;
}

export function withCorrelationId<T extends Action>(
  action: T,
  generateId: GenerateIdFn = defaultGenerateId
): ActionWithCorrelationId<T> {
  return Object.assign({}, action, { correlationId: generateId() });
}

export function filterActionsWithCorrelationId(
  action: ActionWithCorrelationId,
  allowedTypes: string[]
): OperatorFunction<Action, ActionWithCorrelationId> {
  return pipe(
    filter(
      (action: Action): action is ActionWithCorrelationId =>
        "correlationId" in action
    ),
    filter((action: ActionWithCorrelationId) =>
      allowedTypes.includes(action.type)
    )
  );
}