# watch.ludic - last legs: warmth, food or water at zero starts ten seconds of countdown; anything
# above five on all three calls it off; the countdown running out is a collapse, as a fact
const LAST_LEGS: float = 10.0
const GENTLE_FLOOR: float = 22.0

function nd_empty(needs_st: NeedsState) -> int {
  let lv = nd_lv(needs_st)
  if lv[NEED_WARMTH] == 0.0 { return NEED_WARMTH }
  if lv[NEED_FOOD] == 0.0 { return NEED_FOOD }
  if lv[NEED_WATER] == 0.0 { return NEED_WATER }
  return -1
}

function nd_clear(needs_st: NeedsState) -> bool {
  let lv = nd_lv(needs_st)
  return lv[NEED_WARMTH] > 5.0 and lv[NEED_FOOD] > 5.0 and lv[NEED_WATER] > 5.0
}

# Gentle: a need that runs down stops just above where the legs start to go
function nd_gentle(needs_st: mut NeedsState) -> void {
  let lv = nd_lv(needs_st)
  lv[NEED_WARMTH] = Math.max(lv[NEED_WARMTH], GENTLE_FLOOR)
  lv[NEED_FOOD] = Math.max(lv[NEED_FOOD], GENTLE_FLOOR)
  lv[NEED_WATER] = Math.max(lv[NEED_WATER], GENTLE_FLOOR)
  needs_st.nd_legs = 0.0
}

# `dt` real seconds; run it after everything this frame that could fill a need
export function needs_watch(needs_st: mut NeedsState, dt: float) -> void {
  if NeedsWorld.held() { return }
  if NeedsWorld.gentle() {
    nd_gentle(needs_st)
    return
  }
  let need = nd_empty(needs_st)
  if need < 0 {
    if needs_st.nd_legs > 0.0 and nd_clear(needs_st) {
      needs_st.nd_legs = 0.0
      nd_fact(needs_st, NEEDS_RESTORED, needs_st.nd_last)
    }
    return
  }
  if needs_st.nd_legs == 0.0 {
    needs_st.nd_legs = LAST_LEGS
    needs_st.nd_last = need
    nd_fact(needs_st, NEEDS_CRITICAL, need)
    return
  }
  needs_st.nd_legs = needs_st.nd_legs - dt
  if needs_st.nd_legs > 0.0 { return }
  needs_st.nd_legs = 0.0
  nd_fact(needs_st, NEEDS_COLLAPSED, needs_st.nd_last)
}