// m13 life app: the same wiring as Snake and Pong, with a third kind of input, the mouse.
import { LW, LH, LCELL, initialLife, LifeAction } from './model.js'
import { lifeUpdate } from './rules.js'
import { lifeView } from './view.js'
import { map as mapIO, randomSeed, drawScene } from '../io.js'
import { keyDowns, clicks, interval, map, filterMap, merge, scan, startWith, clampTime } from '../stream.js'
import { MAX_GAP_MS } from '../app.js'
/** @import { LifeState, Stream, Program } from '../types' */

/** Milliseconds between two generations while the world runs. */
export const GEN_MS = 150

const keys = {
  ' ': LifeAction.TogglePause,
  n: LifeAction.Step, N: LifeAction.Step,
  c: LifeAction.Clear, C: LifeAction.Clear,
  r: LifeAction.Randomize, R: LifeAction.Randomize,
}

/** A key to an action, or null.
 * @type {(key: string) => LifeAction | null} */
export const lifeKey = (key) => (Object.hasOwn(keys, key) ? keys[key] : null)

/** A click at canvas pixel (x, y) to `Toggle` of the cell under it, or null when it is not on the board.
 * @type {(x: number, y: number) => LifeAction | null} */
export const lifeClick = (x, y) => {
  const cell = { x: Math.floor(x / LCELL), y: Math.floor(y / LCELL) }
  return x >= 0 && y >= 0 && cell.x < LW && cell.y < LH ? LifeAction.Toggle(cell) : null
}

/** @type {Stream<LifeAction>} */
export const lifeActions = merge(
  merge(
    map(interval(GEN_MS), () => LifeAction.Frame),
    filterMap(keyDowns, lifeKey)),
  filterMap(clicks, (p) => lifeClick(p.x, p.y)))

/** @type {(seed: number, actions: Stream<LifeAction>) => Stream<LifeState>} */
export const lifeStates = (seed, actions) =>
  startWith(scan(actions, lifeUpdate, initialLife(seed)), initialLife(seed))

/** @type {Program} */
export const lifeMain = mapIO(randomSeed, (seed) =>
  clampTime(map(lifeStates(seed, lifeActions), (state) => drawScene(lifeView(state))), MAX_GAP_MS))