fix: more casino, economy, gameplay, security, and world data hardening gaps

1 files changed, 16 insertions, 1 deletions

diff --git a/internal/game/cmd_shop.go b/internal/game/cmd_shop.go
index f3211e0..e2209fc 100644
--- a/internal/game/cmd_shop.go
+++ b/internal/game/cmd_shop.go
@@ -345,10 +345,25 @@ func (g *Game) doShopSell(sess *net.Session, mob *world.MobInstance, input strin
 	}
 
 	stock := g.MobStore.ShopStockOf(mob.InstanceID, match.ID)
+	// Only sell as many as the balance headroom can pay for: grantCredits
+	// clamps at the economy cap, so selling past it would consume the items
+	// and destroy the excess credits (the pickup paths take only the headroom).
+	headroom := creditHeadroom(p)
 	total := 0
+	sellQty := 0
 	for k := 0; k < actualQty; k++ {
-		total += mob.Shop.SellPrice(value, stock+k)
+		price := mob.Shop.SellPrice(value, stock+k)
+		if total+price > headroom {
+			break
+		}
+		total += price
+		sellQty++
+	}
+	if sellQty <= 0 {
+		sess.WriteLine("You can't carry any more credits.")
+		return
 	}
+	actualQty = sellQty
 
 	p.RemoveItem(match.ID, actualQty)
 	g.grantCredits(p, total)