up3

server/block/lectern.go

@@ -0,0 +1,169 @@
+package block
+
+import (
+	"fmt"
+	"github.com/df-mc/dragonfly/server/block/cube"
+	"github.com/df-mc/dragonfly/server/block/model"
+	"github.com/df-mc/dragonfly/server/internal/nbtconv"
+	"github.com/df-mc/dragonfly/server/item"
+	"github.com/df-mc/dragonfly/server/world"
+	"github.com/df-mc/dragonfly/server/world/sound"
+	"github.com/go-gl/mathgl/mgl64"
+	"time"
+)
+
+// Lectern is a librarian's job site block found in villages. It is used to hold books for multiple players to read in
+// multiplayer.
+// TODO: Redstone functionality.
+type Lectern struct {
+	bass
+	sourceWaterDisplacer
+
+	// Facing represents the direction the Lectern is facing.
+	Facing cube.Direction
+	// Book is the book currently held by the Lectern.
+	Book item.Stack
+	// Page is the page the Lectern is currently on in the book.
+	Page int
+}
+
+// Model ...
+func (Lectern) Model() world.BlockModel {
+	return model.Lectern{}
+}
+
+// FuelInfo ...
+func (Lectern) FuelInfo() item.FuelInfo {
+	return newFuelInfo(time.Second * 15)
+}
+
+// SideClosed ...
+func (Lectern) SideClosed(cube.Pos, cube.Pos, *world.Tx) bool {
+	return false
+}
+
+// BreakInfo ...
+func (l Lectern) BreakInfo() BreakInfo {
+	d := []item.Stack{item.NewStack(Lectern{}, 1)}
+	if !l.Book.Empty() {
+		d = append(d, l.Book)
+	}
+	return newBreakInfo(2.5, alwaysHarvestable, axeEffective, simpleDrops(d...))
+}
+
+// UseOnBlock ...
+func (l Lectern) UseOnBlock(pos cube.Pos, face cube.Face, _ mgl64.Vec3, tx *world.Tx, user item.User, ctx *item.UseContext) (used bool) {
+	pos, _, used = firstReplaceable(tx, pos, face, l)
+	if !used {
+		return false
+	}
+	l.Facing = user.Rotation().Direction().Opposite()
+	place(tx, pos, l, user, ctx)
+	return placed(ctx)
+}
+
+// readableBook represents a book that can be read through a lectern.
+type readableBook interface {
+	// TotalPages returns the total number of pages in the book.
+	TotalPages() int
+	// Page returns a specific page from the book and true when the page exists. It will otherwise return an empty string
+	// and false.
+	Page(page int) (string, bool)
+}
+
+// Activate ...
+func (l Lectern) Activate(pos cube.Pos, _ cube.Face, tx *world.Tx, u item.User, ctx *item.UseContext) bool {
+	if !l.Book.Empty() {
+		if opener, ok := u.(ContainerOpener); ok {
+			opener.OpenBlockContainer(pos, tx)
+			return true
+		}
+		return false
+	}
+
+	held, _ := u.HeldItems()
+	if _, ok := held.Item().(readableBook); !ok {
+		// We can't put a non-book item on the lectern.
+		return false
+	}
+
+	l.Book, l.Page = held, 0
+	tx.SetBlock(pos, l, nil)
+
+	tx.PlaySound(pos.Vec3Centre(), sound.LecternBookPlace{})
+	ctx.SubtractFromCount(1)
+	return true
+}
+
+// Punch ...
+func (l Lectern) Punch(pos cube.Pos, _ cube.Face, tx *world.Tx, _ item.User) {
+	if l.Book.Empty() {
+		// We can't remove a book from the lectern if there isn't one.
+		return
+	}
+
+	dropItem(tx, l.Book, pos.Side(cube.FaceUp).Vec3Middle())
+
+	l.Book = item.Stack{}
+	tx.SetBlock(pos, l, nil)
+	tx.PlaySound(pos.Vec3Centre(), sound.Attack{})
+}
+
+// TurnPage updates the page the lectern is currently on to the page given.
+func (l Lectern) TurnPage(pos cube.Pos, tx *world.Tx, page int) error {
+	if page == l.Page {
+		// We're already on the correct page, so we don't need to do anything.
+		return nil
+	}
+	if l.Book.Empty() {
+		return fmt.Errorf("lectern at %v is empty", pos)
+	}
+	if r, ok := l.Book.Item().(readableBook); ok && (page >= r.TotalPages() || page < 0) {
+		return fmt.Errorf("page number %d is out of bounds", page)
+	}
+	l.Page = page
+	tx.SetBlock(pos, l, nil)
+	return nil
+}
+
+// EncodeNBT ...
+func (l Lectern) EncodeNBT() map[string]any {
+	m := map[string]any{
+		"hasBook": boolByte(!l.Book.Empty()),
+		"page":    int32(l.Page),
+		"id":      "Lectern",
+	}
+	if r, ok := l.Book.Item().(readableBook); ok {
+		m["book"] = nbtconv.WriteItem(l.Book, true)
+		m["totalPages"] = int32(r.TotalPages())
+	}
+	return m
+}
+
+// DecodeNBT ...
+func (l Lectern) DecodeNBT(m map[string]any) any {
+	l.Page = int(nbtconv.Int32(m, "page"))
+	l.Book = nbtconv.MapItem(m, "book")
+	return l
+}
+
+// EncodeItem ...
+func (Lectern) EncodeItem() (name string, meta int16) {
+	return "minecraft:lectern", 0
+}
+
+// EncodeBlock ...
+func (l Lectern) EncodeBlock() (string, map[string]any) {
+	return "minecraft:lectern", map[string]any{
+		"minecraft:cardinal_direction": l.Facing.String(),
+		"powered_bit":                  uint8(0), // We don't support redstone, anyway.
+	}
+}
+
+// allLecterns ...
+func allLecterns() (lecterns []world.Block) {
+	for _, f := range cube.Directions() {
+		lecterns = append(lecterns, Lectern{Facing: f})
+	}
+	return
+}