basic inventory support

bot/screen/screen.go

@@ -0,0 +1,90 @@
+package screen
+
+import (
+	"io"
+
+	"github.com/Tnze/go-mc/bot"
+	"github.com/Tnze/go-mc/chat"
+	"github.com/Tnze/go-mc/data/packetid"
+	pk "github.com/Tnze/go-mc/net/packet"
+)
+
+type Manager struct {
+	Screens map[byte]Container
+}
+
+func NewManager(c *bot.Client) *Manager {
+	m := &Manager{Screens: make(map[byte]Container)}
+	m.Screens[0] = &Inventory{}
+	c.Events.AddListener(
+		bot.PacketHandler{Priority: 64, ID: packetid.OpenWindow, F: m.onOpenScreen},
+	)
+	return m
+}
+
+func (m *Manager) onOpenScreen(p pk.Packet) error {
+	var (
+		ContainerID pk.VarInt
+		Type        pk.VarInt
+		Title       chat.Message
+	)
+	if err := p.Scan(&ContainerID, &Type, &Title); err != nil {
+		return Error{err}
+	}
+	// TODO: Create the specified container
+	return nil
+}
+
+func (m *Manager) onSetContentPacket(p pk.Packet) error {
+	var (
+		ContainerID pk.UnsignedByte
+		Count       pk.Short
+		SlotData    []slot
+	)
+	if err := p.Scan(
+		&ContainerID,
+		&Count, pk.Ary{
+			Len: &Count,
+			Ary: &SlotData,
+		}); err != nil {
+		return Error{err}
+	}
+	container := m.Screens[byte(ContainerID)]
+	for i, v := range SlotData {
+		container.SetSlot(i, int32(v.id), byte(v.count), v.nbt)
+	}
+	return nil
+}
+
+type slot struct {
+	present pk.Boolean
+	id      pk.VarInt
+	count   pk.Byte
+	nbt     interface{}
+}
+
+func (s *slot) ReadFrom(r io.Reader) (n int64, err error) {
+	return pk.Tuple{
+		&s.present, pk.Opt{Has: &s.present,
+			Field: pk.Tuple{
+				&s.id, &s.count, pk.NBT(&s.nbt),
+			},
+		},
+	}.ReadFrom(r)
+}
+
+type Container interface {
+	SetSlot(i int, id int32, count byte, NBT interface{})
+}
+
+type Error struct {
+	Err error
+}
+
+func (e Error) Error() string {
+	return "bot/screen: " + e.Err.Error()
+}
+
+func (e Error) Unwrap() error {
+	return e.Err
+}