import {
  endEvent,
  Event,
  Scope,
  EventStream,
  EventStreamSeed,
  toEvent,
} from "./abstractions"
import { applyScopeMaybe } from "./applyscope"
import { fromPoll } from "./frompoll"
import { rename } from "./util"

/**
 Creates a stream containing given
 values (given as array). Delivered with given interval in milliseconds.

 @param delay between elements, in milliseconds
 @param array of values or events
 @typeparam V Type of stream elements

 */
export function sequentially<V>(
  delay: number,
  values: (V | Event<V>)[],
  scope: Scope
): EventStream<V>
export function sequentially<V>(
  delay: number,
  values: (V | Event<V>)[]
): EventStreamSeed<V>

export function sequentially<V>(
  delay: number,
  values: (V | Event<V>)[],
  scope?: Scope
): any {
  var index = 0
  return applyScopeMaybe(
    rename(
      ["sequentially", [delay, values]],
      fromPoll<V>(delay, () => {
        var value = values[index++]
        if (index < values.length) {
          return value
        } else if (index === values.length) {
          return [toEvent(value), endEvent]
        } else {
          return endEvent
        }
      })
    ),
    scope
  )
}