up3

server/session/handler_beacon.go

@@ -0,0 +1,78 @@
+package session
+
+import (
+	"fmt"
+	"github.com/df-mc/dragonfly/server/block"
+	"github.com/df-mc/dragonfly/server/entity/effect"
+	"github.com/df-mc/dragonfly/server/item"
+	"github.com/df-mc/dragonfly/server/world"
+	"github.com/sandertv/gophertunnel/minecraft/protocol"
+)
+
+// beaconInputSlot is the slot index of the input item in the beacon.
+const beaconInputSlot = 0x1b
+
+// handleBeaconPayment handles the selection of effects in a beacon and the removal of the item used to pay
+// for those effects.
+func (h *ItemStackRequestHandler) handleBeaconPayment(a *protocol.BeaconPaymentStackRequestAction, s *Session, tx *world.Tx) error {
+	slot := protocol.StackRequestSlotInfo{
+		Container: protocol.FullContainerName{ContainerID: protocol.ContainerBeaconPayment},
+		Slot:      beaconInputSlot,
+	}
+	// First check if there actually is a beacon opened.
+	if !s.containerOpened.Load() {
+		return fmt.Errorf("no beacon container opened")
+	}
+	pos := *s.openedPos.Load()
+	beacon, ok := tx.Block(pos).(block.Beacon)
+	if !ok {
+		return fmt.Errorf("no beacon container opened")
+	}
+
+	// Check if the item present in the beacon slot is valid.
+	payment, _ := h.itemInSlot(slot, s, tx)
+	if payable, ok := payment.Item().(item.BeaconPayment); !ok || !payable.PayableForBeacon() {
+		return fmt.Errorf("item %#v in beacon slot cannot be used as payment", payment)
+	}
+
+	// Check if the effects are valid and allowed for the beacon's level.
+	if !h.validBeaconEffect(a.PrimaryEffect, beacon) {
+		return fmt.Errorf("primary effect selected is not allowed: %v for level %v", a.PrimaryEffect, beacon.Level())
+	} else if !h.validBeaconEffect(a.SecondaryEffect, beacon) || (beacon.Level() < 4 && a.SecondaryEffect != 0) {
+		return fmt.Errorf("secondary effect selected is not allowed: %v for level %v", a.SecondaryEffect, beacon.Level())
+	}
+
+	primary, pOk := effect.ByID(int(a.PrimaryEffect))
+	secondary, sOk := effect.ByID(int(a.SecondaryEffect))
+	if pOk {
+		beacon.Primary = primary.(effect.LastingType)
+	}
+	if sOk {
+		beacon.Secondary = secondary.(effect.LastingType)
+	}
+	tx.SetBlock(pos, beacon, nil)
+
+	// The client will send a Destroy action after this action, but we can't rely on that because the client
+	// could just not send it.
+	// We just ignore the next Destroy action and set the item to air here.
+	h.setItemInSlot(slot, item.Stack{}, s, tx)
+	h.ignoreDestroy = true
+	return nil
+}
+
+// validBeaconEffect checks if the ID passed is a valid beacon effect.
+func (h *ItemStackRequestHandler) validBeaconEffect(id int32, beacon block.Beacon) bool {
+	switch id {
+	case 1, 3:
+		return beacon.Level() >= 1
+	case 8, 11:
+		return beacon.Level() >= 2
+	case 5:
+		return beacon.Level() >= 3
+	case 10:
+		return beacon.Level() >= 4
+	case 0:
+		return true
+	}
+	return false
+}