// ...
const HANDLER = {
  [ACTION.CONTAINER_SIZE_CHANGE]: (state, containerSize) => ({
    ...state,
    containerSize,
    ...getProjectors(containerSize, state.game.size)
  }),
  [ACTION.KEY_DOWN]: (state, key) => {
    if (MOVEMENT_KEYS.LEFT.includes(key)) {
      return { ...state, movement: MOVEMENT.LEFT }
    } else if (MOVEMENT_KEYS.RIGHT.includes(key)) {
      return { ...state, movement: MOVEMENT.RIGHT }
    }
    return state
  },
  [ACTION.KEY_UP]: (state, key) => {
    const newState = { ...state, movement: undefined }
    if (key === STOP_KEY) {
      if (state.stopTime) {
        return { ...newState, stopTime: undefined, time: state.time + Date.now() - state.stopTime}
      } else {
        return { ...newState, stopTime: Date.now() }
      }
    }
    return newState
  },
  [ACTION.TICK]: state => {
    if (state.stopTime) return state

    const time = Date.now()
    const newGame = getNewGameState(state.game, state.movement, time - state.time)
    const newState = { ...state, time }
    if (newGame.lives < 1) {
      return { ...newState, game: getGameStateFromLevel(LEVELS[state.level]) }
    } else if (newGame.blocks.length < 1) {
      const level = state.level === LEVELS.length ? state.level : state.level + 1
      localStorage.setItem('level', level)
      const game = getGameStateFromLevel(LEVELS[state.level])
      return {
        ...newState,
        level,
        game,
        ...getProjectors(state.containerSize, game.size)
      }
    }
    return { ...newState, game: newGame }
  }
}