# prefabs.ludic — prefabs: a model with preset fields, chained (`Grunt: Foe: Creature`),
# spawned by name with overrides, `spawn` as an expression, `Prefab.spawn` / `spawn_at`
# by a runtime name, and `self()` inside @OnSpawn. Deterministic; prints:
#   230159 30 0 7 44 -1 2
program Prefabs {
  import "ludic.core/components.ludic"
  property Enemy { kind: int = 0, hp: int = 10, team: int = 0 }
  model Creature { Position, Enemy }
  prefab Foe: Creature { Enemy { team: 2, hp: 1 }, Position { y: 9 } }
  prefab Grunt: Foe { Enemy { kind: 1, hp: 30 } }
  state PrefabsState {
    last: int = -1
  }
  @OnSpawn(Creature) handler Remember(prefabs_st: mut PrefabsState) { prefabs_st.last = self() }
  entry (prefabs_st: PrefabsState) {
    let g = spawn Grunt { Position { x: 5 } }                     # Foe's presets, Grunt's, then this
    print(Enemy.of(g).team * 100000 + Enemy.of(g).hp * 1000 + Enemy.of(g).kind * 100 + Position.of(g).x * 10 + Position.of(g).y)
    let n = Prefab.spawn(name: "Grunt")
    print(Enemy.of(n).hp)
    print(g)                                                       # the first entity
    let placed = Prefab.spawn_at(name: "Foe", at: IVec2.make(7, 44))
    print(Position.of(placed).x)
    print(Position.of(placed).y)
    print(Prefab.spawn(name: "Nope"))                              # no such prefab
    print(prefabs_st.last)                                                    # self() in the hook: the last spawn
  }
}