# ============================================================================
# systems_tileskin.ludic — the engine-owned tilemap-render system.
#
# A game that builds its world with Map.row(...) used to draw it by hand — a loop over
# every cell calling a sprite draw per glyph. Declare one `TileSkin` entity per glyph
# (from ludic.core) and the engine paints the whole Map.* grid each Render frame,
# BEFORE the sprite system, so actors land on top of the floor and walls:
#
#   spawn Wall { TileSkin { glyph: '#', sprite: wall_id, atlas: 1 } }
#
# Cells whose glyph has no skin are left to the clear colour (a flat floor is free).
# Runs through the same draw chokepoints as sprites (camera / zoom / clip), integer,
# deterministic. Spliced only when a game declares TileSkin.
#
#   property TileSkin { glyph: int, sprite: int, atlas: int = 1, size: int = 16, scale: int = 1 }
# ============================================================================
import "atlas.ludic"

function esys_tileskin(rt_atlas_st: mut RtAtlasState, rt_core_st: mut RtCoreState, rt_image_st: RtImageState) -> void {
  let P = World.prop_id("TileSkin")
  if P < 0 { return }
  let f_glyph  = World.field_id(P, "glyph")
  let f_sprite = World.field_id(P, "sprite")
  let f_atlas  = World.field_id(P, "atlas")
  let f_size   = World.field_id(P, "size")
  let f_scale  = World.field_id(P, "scale")
  if (f_glyph < 0) or (f_sprite < 0) { return }
  var e = World.query_next(P, 0)
  while e >= 0 {
    let glyph  = World.get(e, P, f_glyph)
    let sprite = World.get(e, P, f_sprite)
    var is_atlas = 1
    if f_atlas >= 0 { is_atlas = World.get(e, P, f_atlas) }
    var size = 16
    if f_size >= 0 { let sv = World.get(e, P, f_size);  if sv > 0 { size = sv } }
    var sc = 1
    if f_scale >= 0 { let cv = World.get(e, P, f_scale);  if cv > 1 { sc = cv } }
    var ty = 0
    while ty < rt_core_st.rt_maph {
      var tx = 0
      while tx < rt_core_st.rt_mapw {
        if rt_tile(rt_core_st, tx, ty) == glyph {
          if is_atlas != 0 { atlas_draw_ex(rt_atlas_st, rt_core_st, rt_image_st, sprite, tx * size, ty * size, sc, 0, 0) }
          else { rt_draw_sprite_ex(rt_core_st, rt_image_st, sprite, tx * size, ty * size, sc, 0, 0) }
        }
        tx += 1
      }
      ty += 1
    }
    e = World.query_next(P, e + 1)
  }
}