fix: harden engine across casino, economy, concurrency, security, and content

1 files changed, 45 insertions, 11 deletions

diff --git a/internal/game/cmd_wear.go b/internal/game/cmd_wear.go
index a02fd3b..5a293de 100644
--- a/internal/game/cmd_wear.go
+++ b/internal/game/cmd_wear.go
@@ -101,7 +101,7 @@ func (g *Game) doWear(sess *net.Session, input string) {
 			sess.WriteLine("Your inventory is full.")
 			return
 		}
-		p.SetInvSlot(freeSlot, &player.InventorySlot{ItemID: existingItemID, Quantity: 1})
+		p.SetInvSlot(freeSlot, g.displacedEquipSlot(p, existingItemID))
 	}
 
 	if slot.Quantity > 1 {
@@ -127,6 +127,24 @@ func (g *Game) doWear(sess *net.Session, input string) {
 	sess.WriteLine(fmt.Sprintf("You %s %s.", verb, g.itemColorize(sess, def, match.Name)))
 }
 
+// displacedEquipSlot builds the inventory slot that receives an item
+// displaced by a swap. The item's equipped quality (EquipQuality, kept
+// because the equipment entry alone cannot carry a charge) is stamped onto
+// the returned stack and cleared from the map, so the returned item keeps
+// merging and charging like one carried normally; leaving the entry behind
+// would let act_burn charge a stale record or a zeroed slot.
+func (g *Game) displacedEquipSlot(p *player.Player, itemID string) *player.InventorySlot {
+	slot := &player.InventorySlot{ItemID: itemID, Quantity: 1}
+	if q, ok := p.EquipQuality[itemID]; ok {
+		slot.Quality = q
+		if def, _ := g.ItemStore.Load(itemID); def != nil {
+			slot.MaxQuality = def.MaxQuality
+		}
+		delete(p.EquipQuality, itemID)
+	}
+	return slot
+}
+
 func (g *Game) equipAmmo(sess *net.Session, p *player.Player, invIdx int, slot *player.InventorySlot, def *item.ItemDef, qty int) {
 	transferQty := slot.Quantity
 	if qty > 0 && qty < transferQty {
@@ -135,7 +153,12 @@ func (g *Game) equipAmmo(sess *net.Session, p *player.Player, invIdx int, slot *
 
 	existingAmmoID, hasAmmo := p.Equipment[item.SlotAmmo]
 	if hasAmmo && existingAmmoID != slot.ItemID {
-		g.unequipAmmo(p)
+		// The equipped stack stays equipped when there is nowhere to put
+		// it; equipping the new stack would otherwise strand the old one.
+		if !g.unequipAmmo(p) {
+			sess.WriteLine("Your inventory is full.")
+			return
+		}
 	}
 
 	if slot.Quantity <= transferQty {
@@ -156,26 +179,35 @@ func (g *Game) equipAmmo(sess *net.Session, p *player.Player, invIdx int, slot *
 	sess.WriteLine(fmt.Sprintf("You equip %s (x%d).", displayName, p.AmmoQty))
 }
 
-func (g *Game) unequipAmmo(p *player.Player) {
+// unequipAmmo returns the equipped ammo to the inventory and reports whether
+// the equipped stack is now stored. With nowhere to put it the ammo stays
+// equipped: the equipment entry is only cleared once the stack has actually
+// been merged into an inventory stack or placed in a free slot.
+func (g *Game) unequipAmmo(p *player.Player) bool {
 	ammoID, ok := p.Equipment[item.SlotAmmo]
 	if !ok || p.AmmoQty <= 0 {
-		return
+		return true
 	}
+	quality, maxQuality := g.pickedStackProps(ammoID)
 	for i := 0; i < 28; i++ {
 		s := p.InvSlot(i)
-		if s != nil && s.ItemID == ammoID {
+		// Only a stack with the properties a fresh stack gets may absorb the
+		// equipped stack (see pickedStackProps).
+		if s != nil && s.ItemID == ammoID && s.Quality == quality && s.MaxQuality == maxQuality {
 			s.Quantity += p.AmmoQty
 			delete(p.Equipment, item.SlotAmmo)
 			p.AmmoQty = 0
-			return
+			return true
 		}
 	}
 	freeSlot := p.FirstFreeSlot()
-	if freeSlot >= 0 {
-		p.SetInvSlot(freeSlot, &player.InventorySlot{ItemID: ammoID, Quantity: p.AmmoQty})
+	if freeSlot < 0 {
+		return false
 	}
+	p.SetInvSlot(freeSlot, g.newInventorySlot(ammoID, p.AmmoQty))
 	delete(p.Equipment, item.SlotAmmo)
 	p.AmmoQty = 0
+	return true
 }
 
 func (g *Game) doWearAll(sess *net.Session) {
@@ -235,8 +267,10 @@ func (g *Game) doWearAll(sess *net.Session) {
 					continue
 				}
 				existingID, hasAmmo := p.Equipment[item.SlotAmmo]
-				if hasAmmo && existingID != best.itemID {
-					g.unequipAmmo(p)
+				// No free slot for the equipped stack: leave it equipped and
+				// skip this item rather than delete the old stack.
+				if hasAmmo && existingID != best.itemID && !g.unequipAmmo(p) {
+					continue
 				}
 				transferQty := invSlot.Quantity
 				p.SetInvSlot(best.invSlot, nil)
@@ -256,7 +290,7 @@ func (g *Game) doWearAll(sess *net.Session) {
 			if freeSlot == -1 {
 				continue
 			}
-			p.SetInvSlot(freeSlot, &player.InventorySlot{ItemID: existing, Quantity: 1})
+			p.SetInvSlot(freeSlot, g.displacedEquipSlot(p, existing))
 		}
 
 		invSlot := p.InvSlot(best.invSlot)