import { todo } from './todo.js'
import { pure } from './io.js'

/** Milliseconds between game steps. */
export const TICK_MS = 150

/** Milliseconds between animation frames (m10). */
export const FRAME_MS = 25

/**
 * Stream of everything that can happen to the game: `Action.Tick` every TICK_MS (from `interval`),
 * merged with the `Action` for each key press that `keyToAction` recognises (from `keyDowns`).
 */
export const classicActions = { step: () => todo('m09') }

/**
 * (m10) Like `classicActions`, but the clock emits `Action.Frame` every FRAME_MS instead of `Tick` every TICK_MS;
 * key presses are translated by `keyToAction` as before (now including pause and restart).
 */
export const speedActions = { step: () => todo('m10') }

/**
 * Fold a stream of actions into a stream of game states: start from `newGame(seed)`, apply `update` to each action
 * (scan), and emit the initial state first (startWith) so there is something to draw before anything happens.
 */
export const states = (seed, actions) => todo('m09')

/** The drawing of one state, as an IO: `drawScene(view(state))`. */
export const render = (state) => todo('m09')

/**
 * The whole program as a value, `IO<Stream<IO<unit>>>`: ask for a random seed, then turn the stream of
 * states (built from `classicActions` in m09, from `speedActions` after m10) into a stream of drawings (`render`).
 * Nothing runs here.
 */
export const main = pure({ step: () => todo('m09') })