# radar.ludic - the radar's tiers: a range for each compass tier (0 is no radar), which marks it
# shows, and where each falls on a unit disc with ahead at the top

@alloc_ok("at start: the radar's rings, once")
export function compass_config_radar(compass_st: mut CompassState, ranges: []float, from_tier: int) -> void {
  compass_st.cmp_ranges = new []float
  for i in 0 .. len(ranges) { push(compass_st.cmp_ranges, ranges[i]) }
  compass_st.cmp_radar_from = from_tier
}

# how far the radar reaches with the viewer's compass, 0 without one; a tier past the table has
# the last range
export function compass_radar_range(compass_st: CompassState) -> float {
  if compass_st.cmp_ranges == null or len(compass_st.cmp_ranges) == 0 { return 0.0 }
  let t = CompassWorld.tier()
  if t < 0 { return 0.0 }
  if t >= len(compass_st.cmp_ranges) { return compass_st.cmp_ranges[len(compass_st.cmp_ranges) - 1] }
  return compass_st.cmp_ranges[t]
}

export function compass_radar_on(compass_st: CompassState) -> bool { return compass_radar_range(compass_st) > 0.0 }

# the i-th mark is a blip: a radar is carried, it is shown there and it is in range
export function compass_radar_has(compass_st: CompassState, i: int) -> bool {
  if i < 0 or i >= compass_count(compass_st) or not compass_radar_on(compass_st) { return false }
  let m = compass_st.cmp_list[i]
  if m.tier < compass_st.cmp_radar_from and m.prio < COMPASS_TRACKED { return false }
  return compass_dist(compass_st, i) <= compass_radar_range(compass_st)
}

# where on a unit disc: x right, y down, so ahead is (0, -1) and the edge is the range
export function compass_radar_x(compass_st: CompassState, i: int) -> float { return -Math.sin(compass_bearing(compass_st, i)) * cmp_radar_frac(compass_st, i) }
export function compass_radar_y(compass_st: CompassState, i: int) -> float { return -Math.cos(compass_bearing(compass_st, i)) * cmp_radar_frac(compass_st, i) }

function cmp_radar_frac(compass_st: CompassState, i: int) -> float {
  let r = compass_radar_range(compass_st)
  if r <= 0.0 { return 0.0 }
  return Math.min(compass_dist(compass_st, i) / r, 1.0)
}