import { Scope, ScopedObservable } from "./abstractions"
import { isObservableSeed, Observable, ObservableSeed } from "./index"
import { constant } from "./index"

/** @hidden */
export function argumentsToObservables<
  V,
  P extends ObservableSeed<V, Observable<any>, ScopedObservable<any>>
>(args: (P | P[] | V)[]): P[] {
  args = <any>Array.prototype.slice.call(args)
  return args.flatMap(<any>singleToObservables)
}

function singleToObservables<T>(
  x: ObservableSeed<any, any, any> | ObservableSeed<any, any, any>[] | T
): Observable<any>[] {
  if (isObservableSeed(x)) {
    return [x.consume()]
  } else if (x instanceof Array) {
    return argumentsToObservables(<any>x) as any
  } else {
    return <any>[constant(x)]
  }
}

/** @hidden */
export function argumentsToObservablesAndFunction<
  V,
  P extends ObservableSeed<V, any, any>
>(args: any[]): [P[], (...args: any[]) => V] {
  if (args[0] instanceof Function) {
    return [
      argumentsToObservables(Array.prototype.slice.call(args, 1)),
      args[0],
    ]
  } else {
    return [
      argumentsToObservables(
        <any>Array.prototype.slice.call(args, 0, args.length - 1)
      ),
      args[args.length - 1],
    ]
  }
}