# pool.ludic — entity pooling stats (#80). Ludic's ECS already recycles freed
# entity slots through a freelist (a despawned slot is reused by the next spawn
# before any new slot is taken), so bullet-hell / horde spawn+despawn does no
# per-spawn allocation and cannot fragment. Pool.* exposes the counters so a game
# can watch the reuse. The key proof: after despawn + respawn, Pool.reserved()
# does NOT grow — the freed slot was reused, not reallocated.
#
# Deterministic; a full run prints:  0 0 3 3 0 2 1 3 0 3 1
program PoolDemo {
  property Mob { hp: int = 0 }
  model M { Mob }

  function bi(b: bool) -> int { if b { return 1 };  return 0 }

  entry {
    print(Pool.reserved())               # 0 — nothing allocated yet
    print(Pool.live())                   # 0

    spawn M { Mob { hp: 1 } }
    spawn M { Mob { hp: 2 } }
    spawn M { Mob { hp: 3 } }
    print(Pool.reserved())               # 3
    print(Pool.live())                   # 3
    print(Pool.free())                   # 0 — no freed slots yet

    let pm = World.prop_id("Mob")
    let e = World.query_next(pm, 0)
    despawn e
    print(Pool.live())                   # 2
    print(Pool.free())                   # 1 — one slot recycled onto the freelist

    spawn M { Mob { hp: 4 } }             # reuses the freed slot
    print(Pool.reserved())               # 3 — NO new slot allocated (pooled, not reallocated)
    print(Pool.free())                   # 0 — the freelist slot was drawn back down
    print(Pool.live())                   # 3

    print(bi(Pool.capacity() >= 3))      # 1 — there is a fixed entity cap to budget against
  }
}