Add stubs for NPC interaction commands

internal/game/game.go

@@ -690,6 +690,11 @@ func (g *Game) DoUnequipItem(p *model.Player, itemID, interfaceID int, slotType
 	pe.DeferUnequipItem(targetItem, interfaceID, slotType)
 }
 
+// DoInteractWithNPC handles a player requesting to interact with an NPC
+func (g *Game) DoInteractWithNPC(p *model.Player, actionIndex, targetID int) {
+	// TODO
+}
+
 // DoUseItem handles a player's request to use an item.
 func (g *Game) DoUseItem(p *model.Player, itemID, interfaceID, actionID int) {
 	// TODO

internal/network/request/interact_npc.go

@@ -0,0 +1,49 @@
+package request
+
+import (
+	"fmt"
+	"github.com/mbpolan/openmcs/internal/network"
+)
+
+const InteractWithNPCAction1RequestHeader byte = 0x9B
+const InteractWithNPCAction2RequestHeader byte = 0x11
+const InteractWithNPCAction3RequestHeader byte = 0x15
+const InteractWithNPCAction4RequestHeader byte = 0x12
+
+// InteractWithNPCRequest is sent when the player interacts with an NPC.
+type InteractWithNPCRequest struct {
+	ActionIndex int
+	TargetID    int
+}
+
+// Read parses the content of the request from a stream. If the data cannot be read, an error will be returned.
+func (p *InteractWithNPCRequest) Read(r *network.ProtocolReader) error {
+	// read 1 byte for the header
+	header, err := r.Uint8()
+	if err != nil {
+		return err
+	}
+
+	// read 2 bytes for the target npc id
+	targetID, err := r.Uint16Alt()
+	if err != nil {
+		return err
+	}
+
+	// translate the header into an action index
+	switch header {
+	case InteractWithNPCAction1RequestHeader:
+		p.ActionIndex = 0
+	case InteractWithNPCAction2RequestHeader:
+		p.ActionIndex = 1
+	case InteractWithNPCAction3RequestHeader:
+		p.ActionIndex = 2
+	case InteractWithNPCAction4RequestHeader:
+		p.ActionIndex = 3
+	default:
+		return fmt.Errorf("unexpected interact with NPC header: %2x", header)
+	}
+
+	p.TargetID = int(targetID)
+	return nil
+}

internal/server/client_handler.go

@@ -537,6 +537,19 @@ func (c *ClientHandler) handleLoop() (clientState, error) {
 
 		c.game.DoSetPlayerDesign(c.player, req.Gender, req.Base, req.BodyColors)
 
+	case request.InteractWithNPCAction1RequestHeader,
+		request.InteractWithNPCAction2RequestHeader,
+		request.InteractWithNPCAction3RequestHeader,
+		request.InteractWithNPCAction4RequestHeader:
+		// the player interacted with an npc
+		var req request.InteractWithNPCRequest
+		err = req.Read(c.reader)
+		if err != nil {
+			break
+		}
+
+		c.game.DoInteractWithNPC(c.player, req.ActionIndex, req.TargetID)
+
 	default:
 		// unknown packet
 		err = fmt.Errorf("unexpected packet header: %2x", header)