# use.ludic - the thing the use key should act on. The ray comes first and proximity is its fallback,
# never its override:
#   under the crosshair and in reach  -> that, whatever else is nearer
#   under the crosshair and too far   -> NOTHING (the prompt says why), within AIM_USE_MAX
#   nothing of that kind aimed at     -> the nearest thing in reach
# A player looking at something who presses the key has said which thing they mean.
export const AIM_USE_THIS: int = 0
export const AIM_USE_NOTHING: int = 1
export const AIM_USE_NEAREST: int = 2

export function aim_use(aim_st: AimState, kind: int) -> int {
  if aim_st.am_kind == kind and aim_st.am_reach { return AIM_USE_THIS }
  if aim_st.am_kind == kind and aim_st.am_dist < AIM_USE_MAX { return AIM_USE_NOTHING }
  return AIM_USE_NEAREST
}

# whether (x, z) is before the view: within `cos_min` of the camera's heading, seen from the body.
# Anything at the feet counts, where a heading means nothing, and so does all of it when the view
# looks straight up or down
const AIM_FEET: float = 1.2
export function aim_ahead(x: float, z: float, cos_min: float) -> bool {
  let dx = x - AimView.body_x()
  let dz = z - AimView.body_z()
  let d = Math.sqrt(dx * dx + dz * dz)
  if d < AIM_FEET { return true }
  let fx = AimView.fx()
  let fz = AimView.fz()
  let f = Math.sqrt(fx * fx + fz * fz)
  if f < 0.0001 { return true }
  return (dx * fx + dz * fz) / (d * f) >= cos_min
}