feat: 优化世界管理界面和世界信息界面 (#4823)

Co-authored-by: 3gf8jv4dv <3gf8jv4dv@gmail.com>

HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldInfoPage.java

@@ -18,6 +18,7 @@
 package org.jackhuang.hmcl.ui.versions;
 
 import com.github.steveice10.opennbt.tag.builtin.*;
+import com.jfoenix.controls.JFXButton;
 import com.jfoenix.controls.JFXComboBox;
 import com.jfoenix.controls.JFXTextField;
 import javafx.beans.property.SimpleBooleanProperty;
@@ -28,27 +29,36 @@ import javafx.scene.Cursor;
 import javafx.scene.control.Label;
 import javafx.scene.control.ScrollPane;
 import javafx.scene.effect.BoxBlur;
+import javafx.scene.image.Image;
+import javafx.scene.image.ImageView;
 import javafx.scene.layout.BorderPane;
 import javafx.scene.layout.HBox;
 import javafx.scene.layout.StackPane;
 import javafx.scene.layout.VBox;
+import javafx.stage.FileChooser;
+import org.glavo.png.javafx.PNGJavaFXUtils;
 import org.jackhuang.hmcl.game.World;
 import org.jackhuang.hmcl.task.Schedulers;
 import org.jackhuang.hmcl.task.Task;
+import org.jackhuang.hmcl.ui.Controllers;
 import org.jackhuang.hmcl.ui.FXUtils;
 import org.jackhuang.hmcl.ui.SVG;
 import org.jackhuang.hmcl.ui.construct.*;
+import org.jetbrains.annotations.PropertyKey;
 
+import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
+import java.nio.file.Path;
 import java.text.DecimalFormat;
 import java.time.Instant;
 import java.util.Arrays;
 import java.util.Locale;
+import java.util.concurrent.Callable;
 
-import static org.jackhuang.hmcl.util.logging.Logger.LOG;
 import static org.jackhuang.hmcl.util.i18n.I18n.formatDateTime;
 import static org.jackhuang.hmcl.util.i18n.I18n.i18n;
+import static org.jackhuang.hmcl.util.logging.Logger.LOG;
 
 /**
  * @author Glavo
@@ -58,6 +68,8 @@ public final class WorldInfoPage extends SpinnerPane {
     private final World world;
     private CompoundTag levelDat;
 
+    ImageView iconImageView = new ImageView();
+
     public WorldInfoPage(WorldManagePage worldManagePage) {
         this.worldManagePage = worldManagePage;
         this.world = worldManagePage.getWorld();
@@ -80,7 +92,7 @@ public final class WorldInfoPage extends SpinnerPane {
         if (!Files.isDirectory(world.getFile()))
             throw new IOException("Not a valid world directory");
 
-        return world.readLevelDat();
+        return world.getLevelData();
     }
 
     private void updateControls() {
@@ -103,98 +115,132 @@ public final class WorldInfoPage extends SpinnerPane {
         {
             BorderPane worldNamePane = new BorderPane();
             {
-                Label label = new Label(i18n("world.name"));
+                setLeftLabel(worldNamePane, "world.name");
-                worldNamePane.setLeft(label);
+                JFXTextField worldNameField = new JFXTextField();
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
+                setRightTextField(worldNamePane, worldNameField, 200);
 
-                Label worldNameLabel = new Label();
+                Tag tag = dataTag.get("LevelName");
-                FXUtils.copyOnDoubleClick(worldNameLabel);
+                if (tag instanceof StringTag stringTag) {
-                worldNameLabel.setText(world.getWorldName());
+                    worldNameField.setText(stringTag.getValue());
-                BorderPane.setAlignment(worldNameLabel, Pos.CENTER_RIGHT);
+
-                worldNamePane.setRight(worldNameLabel);
+                    worldNameField.textProperty().addListener((observable, oldValue, newValue) -> {
+                        if (newValue != null) {
+                            try {
+                                world.setWorldName(newValue);
+                            } catch (Exception e) {
+                                LOG.warning("Failed to set world name", e);
+                            }
+                        }
+                    });
+                } else {
+                    worldNameField.setDisable(true);
+                }
             }
 
             BorderPane gameVersionPane = new BorderPane();
             {
-                Label label = new Label(i18n("world.info.game_version"));
+                setLeftLabel(gameVersionPane, "world.info.game_version");
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
-                gameVersionPane.setLeft(label);
-
                 Label gameVersionLabel = new Label();
-                FXUtils.copyOnDoubleClick(gameVersionLabel);
+                setRightTextLabel(gameVersionPane, gameVersionLabel, () -> world.getGameVersion() == null ? "" : world.getGameVersion().toNormalizedString());
-                if (world.getGameVersion() != null)
-                    gameVersionLabel.setText(world.getGameVersion().toNormalizedString());
-                BorderPane.setAlignment(gameVersionLabel, Pos.CENTER_RIGHT);
-                gameVersionPane.setRight(gameVersionLabel);
             }
 
-            BorderPane randomSeedPane = new BorderPane();
+            BorderPane iconPane = new BorderPane();
             {
+                setLeftLabel(iconPane, "world.icon");
 
-                HBox left = new HBox(8);
+                Runnable onClickAction = () -> Controllers.confirm(
-                BorderPane.setAlignment(left, Pos.CENTER_LEFT);
+                        i18n("world.icon.change.tip"), i18n("world.icon.change"), MessageDialogPane.MessageType.INFO,
-                left.setAlignment(Pos.CENTER_LEFT);
+                        this::changeWorldIcon,
-                randomSeedPane.setLeft(left);
+                        null
+                );
 
-                Label label = new Label(i18n("world.info.random_seed"));
+                FXUtils.limitSize(iconImageView, 32, 32);
+                {
+                    iconImageView.setImage(world.getIcon() == null ? FXUtils.newBuiltinImage("/assets/img/unknown_server.png") : world.getIcon());
+                }
+
+                JFXButton editIconButton = new JFXButton();
+                JFXButton resetIconButton = new JFXButton();
+                {
+                    editIconButton.setGraphic(SVG.EDIT.createIcon(20));
+                    editIconButton.setDisable(worldManagePage.isReadOnly());
+                    FXUtils.onClicked(editIconButton, onClickAction);
+                    FXUtils.installFastTooltip(editIconButton, i18n("button.edit"));
+                    editIconButton.getStyleClass().add("toggle-icon4");
+
+                    resetIconButton.setGraphic(SVG.RESTORE.createIcon(20));
+                    resetIconButton.setDisable(worldManagePage.isReadOnly());
+                    FXUtils.onClicked(resetIconButton, this::clearWorldIcon);
+                    FXUtils.installFastTooltip(resetIconButton, i18n("button.reset"));
+                    resetIconButton.getStyleClass().add("toggle-icon4");
+                }
+
+                HBox hBox = new HBox(8);
+                hBox.setAlignment(Pos.CENTER_LEFT);
+                hBox.getChildren().addAll(iconImageView, editIconButton, resetIconButton);
+
+                iconPane.setRight(hBox);
+            }
+
+            BorderPane seedPane = new BorderPane();
+            {
+                setLeftLabel(seedPane, "world.info.random_seed");
 
                 SimpleBooleanProperty visibility = new SimpleBooleanProperty();
                 StackPane visibilityButton = new StackPane();
+                {
                     visibilityButton.setCursor(Cursor.HAND);
+                    visibilityButton.setAlignment(Pos.BOTTOM_RIGHT);
                     FXUtils.setLimitWidth(visibilityButton, 12);
                     FXUtils.setLimitHeight(visibilityButton, 12);
                     FXUtils.onClicked(visibilityButton, () -> visibility.set(!visibility.get()));
-
-                left.getChildren().setAll(label, visibilityButton);
-
-                Label randomSeedLabel = new Label();
-                FXUtils.copyOnDoubleClick(randomSeedLabel);
-                BorderPane.setAlignment(randomSeedLabel, Pos.CENTER_RIGHT);
-                randomSeedPane.setRight(randomSeedLabel);
-
-                Tag tag = worldGenSettings != null ? worldGenSettings.get("seed") : dataTag.get("RandomSeed");
-                if (tag instanceof LongTag) {
-                    randomSeedLabel.setText(tag.getValue().toString());
                 }
 
+                Label seedLabel = new Label();
+                {
+                    FXUtils.copyOnDoubleClick(seedLabel);
+                    seedLabel.setAlignment(Pos.CENTER_RIGHT);
+
+                    seedLabel.setText(world.getSeed() != null ? world.getSeed().toString() : "");
+
                     BoxBlur blur = new BoxBlur();
                     blur.setIterations(3);
                     FXUtils.onChangeAndOperate(visibility, isVisibility -> {
                         SVG icon = isVisibility ? SVG.VISIBILITY : SVG.VISIBILITY_OFF;
                         visibilityButton.getChildren().setAll(icon.createIcon(12));
-                    randomSeedLabel.setEffect(isVisibility ? null : blur);
+                        seedLabel.setEffect(isVisibility ? null : blur);
                     });
                 }
 
+                HBox right = new HBox(8);
+                {
+                    BorderPane.setAlignment(right, Pos.CENTER_RIGHT);
+                    right.getChildren().setAll(visibilityButton, seedLabel);
+                    seedPane.setRight(right);
+                }
+            }
+
             BorderPane lastPlayedPane = new BorderPane();
             {
-                Label label = new Label(i18n("world.info.last_played"));
+                setLeftLabel(lastPlayedPane, "world.info.last_played");
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
-                lastPlayedPane.setLeft(label);
-
                 Label lastPlayedLabel = new Label();
-                FXUtils.copyOnDoubleClick(lastPlayedLabel);
+                setRightTextLabel(lastPlayedPane, lastPlayedLabel, () -> formatDateTime(Instant.ofEpochMilli(world.getLastPlayed())));
-                lastPlayedLabel.setText(formatDateTime(Instant.ofEpochMilli(world.getLastPlayed())));
-                BorderPane.setAlignment(lastPlayedLabel, Pos.CENTER_RIGHT);
-                lastPlayedPane.setRight(lastPlayedLabel);
             }
 
             BorderPane timePane = new BorderPane();
             {
-                Label label = new Label(i18n("world.info.time"));
+                setLeftLabel(timePane, "world.info.time");
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
-                timePane.setLeft(label);
 
                 Label timeLabel = new Label();
-                FXUtils.copyOnDoubleClick(timeLabel);
+                setRightTextLabel(timePane, timeLabel, () -> {
-                BorderPane.setAlignment(timeLabel, Pos.CENTER_RIGHT);
-                timePane.setRight(timeLabel);
-
                     Tag tag = dataTag.get("Time");
                     if (tag instanceof LongTag) {
                         long days = ((LongTag) tag).getValue() / 24000;
-                    timeLabel.setText(i18n("world.info.time.format", days));
+                        return i18n("world.info.time.format", days);
+                    } else {
+                        return "";
                     }
+                });
             }
 
             OptionToggleButton allowCheatsButton = new OptionToggleButton();
@@ -203,21 +249,7 @@ public final class WorldInfoPage extends SpinnerPane {
                 allowCheatsButton.setDisable(worldManagePage.isReadOnly());
                 Tag tag = dataTag.get("allowCommands");
 
-                if (tag instanceof ByteTag) {
+                checkTagAndSetListener(tag, allowCheatsButton);
-                    ByteTag byteTag = (ByteTag) tag;
-                    byte value = byteTag.getValue();
-                    if (value == 0 || value == 1) {
-                        allowCheatsButton.setSelected(value == 1);
-                        allowCheatsButton.selectedProperty().addListener((o, oldValue, newValue) -> {
-                            byteTag.setValue(newValue ? (byte) 1 : (byte) 0);
-                            saveLevelDat();
-                        });
-                    } else {
-                        allowCheatsButton.setDisable(true);
-                    }
-                } else {
-                    allowCheatsButton.setDisable(true);
-                }
             }
 
             OptionToggleButton generateFeaturesButton = new OptionToggleButton();
@@ -226,28 +258,12 @@ public final class WorldInfoPage extends SpinnerPane {
                 generateFeaturesButton.setDisable(worldManagePage.isReadOnly());
                 Tag tag = worldGenSettings != null ? worldGenSettings.get("generate_features") : dataTag.get("MapFeatures");
 
-                if (tag instanceof ByteTag) {
+                checkTagAndSetListener(tag, generateFeaturesButton);
-                    ByteTag byteTag = (ByteTag) tag;
-                    byte value = byteTag.getValue();
-                    if (value == 0 || value == 1) {
-                        generateFeaturesButton.setSelected(value == 1);
-                        generateFeaturesButton.selectedProperty().addListener((o, oldValue, newValue) -> {
-                            byteTag.setValue(newValue ? (byte) 1 : (byte) 0);
-                            saveLevelDat();
-                        });
-                    } else {
-                        generateFeaturesButton.setDisable(true);
-                    }
-                } else {
-                    generateFeaturesButton.setDisable(true);
-                }
             }
 
             BorderPane difficultyPane = new BorderPane();
             {
-                Label label = new Label(i18n("world.info.difficulty"));
+                setLeftLabel(difficultyPane, "world.info.difficulty");
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
-                difficultyPane.setLeft(label);
 
                 JFXComboBox<Difficulty> difficultyBox = new JFXComboBox<>(Difficulty.items);
                 difficultyBox.setDisable(worldManagePage.isReadOnly());
@@ -255,8 +271,7 @@ public final class WorldInfoPage extends SpinnerPane {
                 difficultyPane.setRight(difficultyBox);
 
                 Tag tag = dataTag.get("Difficulty");
-                if (tag instanceof ByteTag) {
+                if (tag instanceof ByteTag byteTag) {
-                    ByteTag byteTag = (ByteTag) tag;
                     Difficulty difficulty = Difficulty.of(byteTag.getValue());
                     if (difficulty != null) {
                         difficultyBox.setValue(difficulty);
@@ -274,86 +289,93 @@ public final class WorldInfoPage extends SpinnerPane {
                 }
             }
 
+            OptionToggleButton difficultyLockPane = new OptionToggleButton();
+            {
+                difficultyLockPane.setTitle(i18n("world.info.difficulty_lock"));
+                difficultyLockPane.setDisable(worldManagePage.isReadOnly());
+
+                Tag tag = dataTag.get("DifficultyLocked");
+                checkTagAndSetListener(tag, difficultyLockPane);
+            }
+
             basicInfo.getContent().setAll(
-                    worldNamePane, gameVersionPane, randomSeedPane, lastPlayedPane, timePane,
+                    worldNamePane, gameVersionPane, iconPane, seedPane, lastPlayedPane, timePane,
-                    allowCheatsButton, generateFeaturesButton, difficultyPane);
+                    allowCheatsButton, generateFeaturesButton, difficultyPane, difficultyLockPane);
 
             rootPane.getChildren().addAll(ComponentList.createComponentListTitle(i18n("world.info.basic")), basicInfo);
         }
 
         Tag playerTag = dataTag.get("Player");
-        if (playerTag instanceof CompoundTag) {
+        if (playerTag instanceof CompoundTag player) {
-            CompoundTag player = (CompoundTag) playerTag;
             ComponentList playerInfo = new ComponentList();
 
             BorderPane locationPane = new BorderPane();
             {
-                Label label = new Label(i18n("world.info.player.location"));
+                setLeftLabel(locationPane, "world.info.player.location");
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
-                locationPane.setLeft(label);
-
                 Label locationLabel = new Label();
-                FXUtils.copyOnDoubleClick(locationLabel);
+                setRightTextLabel(locationPane, locationLabel, () -> {
-                BorderPane.setAlignment(locationLabel, Pos.CENTER_RIGHT);
-                locationPane.setRight(locationLabel);
-
                     Dimension dim = Dimension.of(player.get("Dimension"));
                     if (dim != null) {
                         String posString = dim.formatPosition(player.get("Pos"));
                         if (posString != null)
-                        locationLabel.setText(posString);
+                            return posString;
                     }
+                    return "";
+                });
             }
 
             BorderPane lastDeathLocationPane = new BorderPane();
             {
-                Label label = new Label(i18n("world.info.player.last_death_location"));
+                setLeftLabel(lastDeathLocationPane, "world.info.player.last_death_location");
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
-                lastDeathLocationPane.setLeft(label);
-
                 Label lastDeathLocationLabel = new Label();
-                FXUtils.copyOnDoubleClick(lastDeathLocationLabel);
+                setRightTextLabel(lastDeathLocationPane, lastDeathLocationLabel, () -> {
-                BorderPane.setAlignment(lastDeathLocationLabel, Pos.CENTER_RIGHT);
+                    Tag tag = player.get("LastDeathLocation");// Valid after 22w14a; prior to this version, the game did not record the last death location data.
-                lastDeathLocationPane.setRight(lastDeathLocationLabel);
+                    if (tag instanceof CompoundTag compoundTag) {
-
+                        Dimension dim = Dimension.of(compoundTag.get("dimension"));
-                Tag tag = player.get("LastDeathLocation");
-                if (tag instanceof CompoundTag) {
-                    Dimension dim = Dimension.of(((CompoundTag) tag).get("dimension"));
                         if (dim != null) {
-                        String posString = dim.formatPosition(((CompoundTag) tag).get("pos"));
+                            String posString = dim.formatPosition(compoundTag.get("pos"));
                             if (posString != null)
-                            lastDeathLocationLabel.setText(posString);
+                                return posString;
                         }
                     }
+                    return "";
+                });
+
             }
 
             BorderPane spawnPane = new BorderPane();
             {
-                Label label = new Label(i18n("world.info.player.spawn"));
+                setLeftLabel(spawnPane, "world.info.player.spawn");
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
-                spawnPane.setLeft(label);
-
                 Label spawnLabel = new Label();
-                FXUtils.copyOnDoubleClick(spawnLabel);
+                setRightTextLabel(spawnPane, spawnLabel, () -> {
-                BorderPane.setAlignment(spawnLabel, Pos.CENTER_RIGHT);
-                spawnPane.setRight(spawnLabel);
 
-                Dimension dim = Dimension.of(player.get("SpawnDimension"));
+                    Dimension dimension;
-                if (dim != null) {
+                    if (player.get("respawn") instanceof CompoundTag respawnTag && respawnTag.get("dimension") != null) { // Valid after 25w07a
-                    Tag x = player.get("SpawnX");
+                        dimension = Dimension.of(respawnTag.get("dimension"));
-                    Tag y = player.get("SpawnY");
+                        Tag posTag = respawnTag.get("pos");
-                    Tag z = player.get("SpawnZ");
 
-                    if (x instanceof IntTag && y instanceof IntTag && z instanceof IntTag)
+                        if (posTag instanceof IntArrayTag intArrayTag && intArrayTag.length() >= 3) {
-                        spawnLabel.setText(dim.formatPosition(((IntTag) x).getValue(), ((IntTag) y).getValue(), ((IntTag) z).getValue()));
+                            return dimension.formatPosition(intArrayTag.getValue(0), intArrayTag.getValue(1), intArrayTag.getValue(2));
                         }
+                    } else if (player.get("SpawnX") instanceof IntTag intX
+                            && player.get("SpawnY") instanceof IntTag intY
+                            && player.get("SpawnZ") instanceof IntTag intZ) { // Valid before 25w07a
+                        // SpawnDimension tag is valid after 20w12a. Prior to this version, the game did not record the respawn point dimension and respawned in the Overworld.
+                        dimension = Dimension.of(player.get("SpawnDimension") == null ? new IntTag("SpawnDimension", 0) : player.get("SpawnDimension"));
+                        if (dimension == null) {
+                            return "";
+                        }
+
+                        return dimension.formatPosition(intX.getValue(), intY.getValue(), intZ.getValue());
+                    }
+
+                    return "";
+                });
             }
 
             BorderPane playerGameTypePane = new BorderPane();
             {
-                Label label = new Label(i18n("world.info.player.game_type"));
+                setLeftLabel(playerGameTypePane, "world.info.player.game_type");
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
-                playerGameTypePane.setLeft(label);
 
                 JFXComboBox<GameType> gameTypeBox = new JFXComboBox<>(GameType.items);
                 gameTypeBox.setDisable(worldManagePage.isReadOnly());
@@ -364,8 +386,7 @@ public final class WorldInfoPage extends SpinnerPane {
                 Tag hardcoreTag = dataTag.get("hardcore");
                 boolean isHardcore = hardcoreTag instanceof ByteTag && ((ByteTag) hardcoreTag).getValue() == 1;
 
-                if (tag instanceof IntTag) {
+                if (tag instanceof IntTag intTag) {
-                    IntTag intTag = (IntTag) tag;
                     GameType gameType = GameType.of(intTag.getValue(), isHardcore);
                     if (gameType != null) {
                         gameTypeBox.setValue(gameType);
@@ -395,33 +416,13 @@ public final class WorldInfoPage extends SpinnerPane {
 
             BorderPane healthPane = new BorderPane();
             {
-                Label label = new Label(i18n("world.info.player.health"));
+                setLeftLabel(healthPane, "world.info.player.health");
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
-                healthPane.setLeft(label);
-
                 JFXTextField healthField = new JFXTextField();
-                healthField.setDisable(worldManagePage.isReadOnly());
+                setRightTextField(healthPane, healthField, 50);
-                healthField.setPrefWidth(50);
-                healthField.setAlignment(Pos.CENTER_RIGHT);
-                BorderPane.setAlignment(healthField, Pos.CENTER_RIGHT);
-                healthPane.setRight(healthField);
 
                 Tag tag = player.get("Health");
-                if (tag instanceof FloatTag) {
+                if (tag instanceof FloatTag floatTag) {
-                    FloatTag floatTag = (FloatTag) tag;
+                    setTagAndTextField(floatTag, healthField);
-                    healthField.setText(new DecimalFormat("#").format(floatTag.getValue().floatValue()));
-
-                    healthField.textProperty().addListener((o, oldValue, newValue) -> {
-                        if (newValue != null) {
-                            try {
-                                floatTag.setValue(Float.parseFloat(newValue));
-                                saveLevelDat();
-                            } catch (Throwable ignored) {
-                            }
-                        }
-                    });
-                    FXUtils.setValidateWhileTextChanged(healthField, true);
-                    healthField.setValidators(new DoubleValidator(i18n("input.number"), true));
                 } else {
                     healthField.setDisable(true);
                 }
@@ -429,33 +430,13 @@ public final class WorldInfoPage extends SpinnerPane {
 
             BorderPane foodLevelPane = new BorderPane();
             {
-                Label label = new Label(i18n("world.info.player.food_level"));
+                setLeftLabel(foodLevelPane, "world.info.player.food_level");
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
-                foodLevelPane.setLeft(label);
-
                 JFXTextField foodLevelField = new JFXTextField();
-                foodLevelField.setDisable(worldManagePage.isReadOnly());
+                setRightTextField(foodLevelPane, foodLevelField, 50);
-                foodLevelField.setPrefWidth(50);
-                foodLevelField.setAlignment(Pos.CENTER_RIGHT);
-                BorderPane.setAlignment(foodLevelField, Pos.CENTER_RIGHT);
-                foodLevelPane.setRight(foodLevelField);
 
                 Tag tag = player.get("foodLevel");
-                if (tag instanceof IntTag) {
+                if (tag instanceof IntTag intTag) {
-                    IntTag intTag = (IntTag) tag;
+                    setTagAndTextField(intTag, foodLevelField);
-                    foodLevelField.setText(String.valueOf(intTag.getValue()));
-
-                    foodLevelField.textProperty().addListener((o, oldValue, newValue) -> {
-                        if (newValue != null) {
-                            try {
-                                intTag.setValue(Integer.parseInt(newValue));
-                                saveLevelDat();
-                            } catch (Throwable ignored) {
-                            }
-                        }
-                    });
-                    FXUtils.setValidateWhileTextChanged(foodLevelField, true);
-                    foodLevelField.setValidators(new NumberValidator(i18n("input.number"), true));
                 } else {
                     foodLevelField.setDisable(true);
                 }
@@ -463,33 +444,13 @@ public final class WorldInfoPage extends SpinnerPane {
 
             BorderPane xpLevelPane = new BorderPane();
             {
-                Label label = new Label(i18n("world.info.player.xp_level"));
+                setLeftLabel(xpLevelPane, "world.info.player.xp_level");
-                BorderPane.setAlignment(label, Pos.CENTER_LEFT);
-                xpLevelPane.setLeft(label);
-
                 JFXTextField xpLevelField = new JFXTextField();
-                xpLevelField.setDisable(worldManagePage.isReadOnly());
+                setRightTextField(xpLevelPane, xpLevelField, 50);
-                xpLevelField.setPrefWidth(50);
-                xpLevelField.setAlignment(Pos.CENTER_RIGHT);
-                BorderPane.setAlignment(xpLevelField, Pos.CENTER_RIGHT);
-                xpLevelPane.setRight(xpLevelField);
 
                 Tag tag = player.get("XpLevel");
-                if (tag instanceof IntTag) {
+                if (tag instanceof IntTag intTag) {
-                    IntTag intTag = (IntTag) tag;
+                    setTagAndTextField(intTag, xpLevelField);
-                    xpLevelField.setText(String.valueOf(intTag.getValue()));
-
-                    xpLevelField.textProperty().addListener((o, oldValue, newValue) -> {
-                        if (newValue != null) {
-                            try {
-                                intTag.setValue(Integer.parseInt(newValue));
-                                saveLevelDat();
-                            } catch (Throwable ignored) {
-                            }
-                        }
-                    });
-                    FXUtils.setValidateWhileTextChanged(xpLevelField, true);
-                    xpLevelField.setValidators(new NumberValidator(i18n("input.number"), true));
                 } else {
                     xpLevelField.setDisable(true);
                 }
@@ -504,6 +465,88 @@ public final class WorldInfoPage extends SpinnerPane {
         }
     }
 
+    private void setLeftLabel(BorderPane borderPane, @PropertyKey(resourceBundle = "assets.lang.I18N") String key) {
+        Label label = new Label(i18n(key));
+        BorderPane.setAlignment(label, Pos.CENTER_LEFT);
+        borderPane.setLeft(label);
+    }
+
+    private void setRightTextField(BorderPane borderPane, JFXTextField textField, int perfWidth) {
+        textField.setDisable(worldManagePage.isReadOnly());
+        textField.setPrefWidth(perfWidth);
+        textField.setAlignment(Pos.CENTER_RIGHT);
+        borderPane.setRight(textField);
+    }
+
+    private void setRightTextLabel(BorderPane borderPane, Label label, Callable<String> setNameCall) {
+        FXUtils.copyOnDoubleClick(label);
+        BorderPane.setAlignment(label, Pos.CENTER_RIGHT);
+        try {
+            label.setText(setNameCall.call());
+        } catch (Exception e) {
+            LOG.warning("Exception happened when setting name", e);
+        }
+        borderPane.setRight(label);
+    }
+
+    private void checkTagAndSetListener(Tag tag, OptionToggleButton toggleButton) {
+        if (tag instanceof ByteTag byteTag) {
+            byte value = byteTag.getValue();
+            if (value == 0 || value == 1) {
+                toggleButton.setSelected(value == 1);
+                toggleButton.selectedProperty().addListener((o, oldValue, newValue) -> {
+                    try {
+                        byteTag.setValue((byte) (newValue ? 1 : 0));
+                        saveLevelDat();
+                    } catch (Exception e) {
+                        toggleButton.setSelected(oldValue);
+                        LOG.warning("Exception happened when saving level.dat", e);
+                    }
+                });
+            } else {
+                toggleButton.setDisable(true);
+            }
+        } else {
+            toggleButton.setDisable(true);
+        }
+    }
+
+    private void setTagAndTextField(IntTag intTag, JFXTextField jfxTextField) {
+        jfxTextField.setText(String.valueOf(intTag.getValue()));
+
+        jfxTextField.textProperty().addListener((o, oldValue, newValue) -> {
+            if (newValue != null) {
+                try {
+                    intTag.setValue(Integer.parseInt(newValue));
+                    saveLevelDat();
+                } catch (Exception e) {
+                    jfxTextField.setText(oldValue);
+                    LOG.warning("Exception happened when saving level.dat", e);
+                }
+            }
+        });
+        FXUtils.setValidateWhileTextChanged(jfxTextField, true);
+        jfxTextField.setValidators(new NumberValidator(i18n("input.number"), true));
+    }
+
+    private void setTagAndTextField(FloatTag floatTag, JFXTextField jfxTextField) {
+        jfxTextField.setText(new DecimalFormat("#").format(floatTag.getValue().floatValue()));
+
+        jfxTextField.textProperty().addListener((o, oldValue, newValue) -> {
+            if (newValue != null) {
+                try {
+                    floatTag.setValue(Float.parseFloat(newValue));
+                    saveLevelDat();
+                } catch (Exception e) {
+                    jfxTextField.setText(oldValue);
+                    LOG.warning("Exception happened when saving level.dat", e);
+                }
+            }
+        });
+        FXUtils.setValidateWhileTextChanged(jfxTextField, true);
+        jfxTextField.setValidators(new DoubleValidator(i18n("input.number"), true));
+    }
+
     private void saveLevelDat() {
         LOG.info("Saving level.dat of world " + world.getWorldName());
         try {
@@ -513,54 +556,34 @@ public final class WorldInfoPage extends SpinnerPane {
         }
     }
 
-    private static final class Dimension {
+    private record Dimension(String name) {
         static final Dimension OVERWORLD = new Dimension(null);
         static final Dimension THE_NETHER = new Dimension(i18n("world.info.dimension.the_nether"));
         static final Dimension THE_END = new Dimension(i18n("world.info.dimension.the_end"));
 
-        final String name;
-
         static Dimension of(Tag tag) {
-            if (tag instanceof IntTag) {
+            if (tag instanceof IntTag intTag) {
-                switch (((IntTag) tag).getValue()) {
+                return switch (intTag.getValue()) {
-                    case 0:
+                    case 0 -> OVERWORLD;
-                        return OVERWORLD;
+                    case 1 -> THE_NETHER;
-                    case 1:
+                    case 2 -> THE_END;
-                        return THE_NETHER;
+                    default -> null;
-                    case 2:
+                };
-                        return THE_END;
+            } else if (tag instanceof StringTag stringTag) {
-                    default:
+                String id = stringTag.getValue();
-                        return null;
+                return switch (id) {
-                }
+                    case "overworld", "minecraft:overworld" -> OVERWORLD;
-            } else if (tag instanceof StringTag) {
+                    case "the_nether", "minecraft:the_nether" -> THE_NETHER;
-                String id = ((StringTag) tag).getValue();
+                    case "the_end", "minecraft:the_end" -> THE_END;
-                switch (id) {
+                    default -> new Dimension(id);
-                    case "overworld":
+                };
-                    case "minecraft:overworld":
-                        return OVERWORLD;
-                    case "the_nether":
-                    case "minecraft:the_nether":
-                        return THE_NETHER;
-                    case "the_end":
-                    case "minecraft:the_end":
-                        return THE_END;
-                    default:
-                        return new Dimension(id);
-                }
             } else {
                 return null;
             }
         }
 
-        private Dimension(String name) {
-            this.name = name;
-        }
-
         String formatPosition(Tag tag) {
-            if (tag instanceof ListTag) {
+            if (tag instanceof ListTag listTag && listTag.size() == 3) {
-                ListTag listTag = (ListTag) tag;
-                if (listTag.size() != 3)
-                    return null;
 
                 Tag x = listTag.get(0);
                 Tag y = listTag.get(1);
@@ -575,8 +598,7 @@ public final class WorldInfoPage extends SpinnerPane {
                 return null;
             }
 
-            if (tag instanceof IntArrayTag) {
+            if (tag instanceof IntArrayTag intArrayTag) {
-                IntArrayTag intArrayTag = (IntArrayTag) tag;
 
                 int x = intArrayTag.getValue(0);
                 int y = intArrayTag.getValue(1);
@@ -609,7 +631,7 @@ public final class WorldInfoPage extends SpinnerPane {
         static final ObservableList<Difficulty> items = FXCollections.observableList(Arrays.asList(values()));
 
         static Difficulty of(int d) {
-            return d >= 0 && d <= items.size() ? items.get(d) : null;
+            return (d >= 0 && d < items.size()) ? items.get(d) : null;
         }
 
         @Override
@@ -633,4 +655,51 @@ public final class WorldInfoPage extends SpinnerPane {
             return i18n("world.info.player.game_type." + name().toLowerCase(Locale.ROOT));
         }
     }
+
+    private void changeWorldIcon() {
+        FileChooser fileChooser = new FileChooser();
+        fileChooser.setTitle(i18n("world.icon.choose.title"));
+        fileChooser.getExtensionFilters().add(new FileChooser.ExtensionFilter(i18n("extension.png"), "*.png"));
+        fileChooser.setInitialFileName("icon.png");
+
+        File file = fileChooser.showOpenDialog(Controllers.getStage());
+        if (file == null) return;
+
+        Image image;
+        try {
+            image = FXUtils.loadImage(file.toPath());
+        } catch (Exception e) {
+            LOG.warning("Failed to load image", e);
+            Controllers.dialog(i18n("world.icon.change.fail.load.text"), i18n("world.icon.change.fail.load.title"), MessageDialogPane.MessageType.ERROR);
+            return;
+        }
+        if ((int) image.getWidth() == 64 && (int) image.getHeight() == 64) {
+            Path output = world.getFile().resolve("icon.png");
+            saveImage(image, output);
+        } else {
+            Controllers.dialog(i18n("world.icon.change.fail.not_64x64.text", (int) image.getWidth(), (int) image.getHeight()), i18n("world.icon.change.fail.not_64x64.title"), MessageDialogPane.MessageType.ERROR);
+        }
+    }
+
+    private void saveImage(Image image, Path path) {
+        Image oldImage = iconImageView.getImage();
+        try {
+            PNGJavaFXUtils.writeImage(image, path);
+            iconImageView.setImage(image);
+            Controllers.showToast(i18n("world.icon.change.succeed.toast"));
+        } catch (IOException e) {
+            LOG.warning("Failed to save world icon " + e.getMessage());
+            iconImageView.setImage(oldImage);
+        }
+    }
+
+    private void clearWorldIcon() {
+        Path output = world.getFile().resolve("icon.png");
+        try {
+            Files.deleteIfExists(output);
+            iconImageView.setImage(FXUtils.newBuiltinImage("/assets/img/unknown_server.png"));
+        } catch (IOException e) {
+            LOG.warning("Failed to delete world icon " + e.getMessage());
+        }
+    }
 }

HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldListItem.java

@@ -19,23 +19,13 @@ package org.jackhuang.hmcl.ui.versions;
 
 import javafx.scene.control.Control;
 import javafx.scene.control.Skin;
-import javafx.stage.FileChooser;
 import org.jackhuang.hmcl.game.World;
-import org.jackhuang.hmcl.game.WorldLockedException;
 import org.jackhuang.hmcl.setting.Profile;
-import org.jackhuang.hmcl.task.Schedulers;
-import org.jackhuang.hmcl.task.Task;
 import org.jackhuang.hmcl.ui.Controllers;
 import org.jackhuang.hmcl.ui.FXUtils;
-import org.jackhuang.hmcl.ui.construct.MessageDialogPane.MessageType;
-import org.jackhuang.hmcl.ui.wizard.SinglePageWizardProvider;
-import org.jackhuang.hmcl.util.StringUtils;
-import org.jackhuang.hmcl.util.io.FileUtils;
 
 import java.nio.file.Path;
 
-import static org.jackhuang.hmcl.util.i18n.I18n.i18n;
-
 public final class WorldListItem extends Control {
     private final World world;
     private final Path backupsDir;
@@ -61,34 +51,15 @@ public final class WorldListItem extends Control {
     }
 
     public void export() {
-        FileChooser fileChooser = new FileChooser();
+        WorldManageUIUtils.export(world);
-        fileChooser.setTitle(i18n("world.export.title"));
-        fileChooser.getExtensionFilters().add(new FileChooser.ExtensionFilter(i18n("world"), "*.zip"));
-        fileChooser.setInitialFileName(world.getWorldName());
-        Path file = FileUtils.toPath(fileChooser.showSaveDialog(Controllers.getStage()));
-        if (file == null) {
-            return;
-        }
-
-        Controllers.getDecorator().startWizard(new SinglePageWizardProvider(controller -> new WorldExportPage(world, file, controller::onFinish)));
     }
 
     public void delete() {
-        Controllers.confirm(
+        WorldManageUIUtils.delete(world, () -> parent.remove(this));
-                i18n("button.remove.confirm"),
-                i18n("world.delete"),
-                () -> Task.runAsync(world::delete)
-                        .whenComplete(Schedulers.javafx(), (result, exception) -> {
-                            if (exception == null) {
-                                parent.remove(this);
-                            } else if (exception instanceof WorldLockedException) {
-                                Controllers.dialog(i18n("world.locked.failed"), null, MessageType.WARNING);
-                            } else {
-                                Controllers.dialog(i18n("world.delete.failed", StringUtils.getStackTrace(exception)), null, MessageType.WARNING);
     }
-                        }).start(),
+
-                null
+    public void copy() {
-        );
+        WorldManageUIUtils.copyWorld(world, parent::refresh);
     }
 
     public void reveal() {

HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldListItemSkin.java

@@ -35,6 +35,7 @@ import org.jackhuang.hmcl.util.ChunkBaseApp;
 import org.jackhuang.hmcl.util.i18n.I18n;
 
 import java.time.Instant;
+import java.util.stream.Stream;
 
 import static org.jackhuang.hmcl.ui.FXUtils.determineOptimalPopupPosition;
 import static org.jackhuang.hmcl.util.StringUtils.parseColorEscapes;
@@ -143,11 +144,24 @@ public final class WorldListItemSkin extends SkinBase<WorldListItem> {
             }
         }
 
+        IconedMenuItem exportMenuItem = new IconedMenuItem(SVG.OUTPUT, i18n("world.export"), item::export, popup);
+        IconedMenuItem deleteMenuItem = new IconedMenuItem(SVG.DELETE, i18n("world.delete"), item::delete, popup);
+        IconedMenuItem duplicateMenuItem = new IconedMenuItem(SVG.CONTENT_COPY, i18n("world.duplicate"), item::copy, popup);
+        boolean worldLocked = world.isLocked();
+        Stream.of(exportMenuItem, deleteMenuItem, duplicateMenuItem)
+                .forEach(iconedMenuItem -> iconedMenuItem.setDisable(worldLocked));
+
         popupMenu.getContent().addAll(
                 new MenuSeparator(),
-                new IconedMenuItem(SVG.OUTPUT, i18n("world.export"), item::export, popup),
+                exportMenuItem,
-                new IconedMenuItem(SVG.DELETE, i18n("world.delete"), item::delete, popup),
+                deleteMenuItem,
-                new IconedMenuItem(SVG.FOLDER_OPEN, i18n("folder.world"), item::reveal, popup));
+                duplicateMenuItem
+        );
+
+        popupMenu.getContent().addAll(
+                new MenuSeparator(),
+                new IconedMenuItem(SVG.FOLDER_OPEN, i18n("folder.world"), item::reveal, popup)
+        );
 
         JFXPopup.PopupVPosition vPosition = determineOptimalPopupPosition(root, popup);
 

HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldManagePage.java

@@ -18,6 +18,7 @@
 package org.jackhuang.hmcl.ui.versions;
 
 import com.jfoenix.controls.JFXPopup;
+import javafx.application.Platform;
 import javafx.beans.property.ObjectProperty;
 import javafx.beans.property.ReadOnlyObjectProperty;
 import javafx.beans.property.SimpleObjectProperty;
@@ -27,6 +28,7 @@ import javafx.scene.layout.Priority;
 import javafx.scene.layout.VBox;
 import org.jackhuang.hmcl.game.World;
 import org.jackhuang.hmcl.setting.Profile;
+import org.jackhuang.hmcl.ui.Controllers;
 import org.jackhuang.hmcl.ui.FXUtils;
 import org.jackhuang.hmcl.ui.SVG;
 import org.jackhuang.hmcl.ui.animation.TransitionPane;
@@ -34,6 +36,7 @@ import org.jackhuang.hmcl.ui.construct.*;
 import org.jackhuang.hmcl.ui.decorator.DecoratorAnimatedPage;
 import org.jackhuang.hmcl.ui.decorator.DecoratorPage;
 import org.jackhuang.hmcl.util.ChunkBaseApp;
+import org.jackhuang.hmcl.util.StringUtils;
 
 import java.io.IOException;
 import java.nio.channels.FileChannel;
@@ -53,6 +56,8 @@ public final class WorldManagePage extends DecoratorAnimatedPage implements Deco
     private final Profile profile;
     private final String id;
 
+    private boolean loadFailed = false;
+
     private final TabHeader header;
     private final TabHeader.Tab<WorldInfoPage> worldInfoTab = new TabHeader.Tab<>("worldInfoPage");
     private final TabHeader.Tab<WorldBackupsPage> worldBackupsTab = new TabHeader.Tab<>("worldBackupsPage");
@@ -65,25 +70,25 @@ public final class WorldManagePage extends DecoratorAnimatedPage implements Deco
     public WorldManagePage(World world, Path backupsDir, Profile profile, String id) {
         this.world = world;
         this.backupsDir = backupsDir;
-
         this.profile = profile;
         this.id = id;
 
+        sessionLockChannel = WorldManageUIUtils.getSessionLockChannel(world);
+        try {
+            world.reloadLevelDat();
+        } catch (IOException e) {
+            LOG.warning("Can not load world level.dat of world: " + world.getFile(), e);
+            loadFailed = true;
+        }
+
         this.worldInfoTab.setNodeSupplier(() -> new WorldInfoPage(this));
         this.worldBackupsTab.setNodeSupplier(() -> new WorldBackupsPage(this));
         this.datapackTab.setNodeSupplier(() -> new DatapackListPage(this));
 
-        this.state = new SimpleObjectProperty<>(State.fromTitle(i18n("world.manage.title", world.getWorldName())));
+        this.state = new SimpleObjectProperty<>(State.fromTitle(i18n("world.manage.title", StringUtils.parseColorEscapes(world.getWorldName()))));
         this.header = new TabHeader(transitionPane, worldInfoTab, worldBackupsTab);
         header.select(worldInfoTab);
 
-        // Does it need to be done in the background?
-        try {
-            sessionLockChannel = world.lock();
-            LOG.info("Acquired lock on world " + world.getFileName());
-        } catch (IOException ignored) {
-        }
-
         setCenter(transitionPane);
 
         BorderPane left = new BorderPane();
@@ -106,37 +111,81 @@ public final class WorldManagePage extends DecoratorAnimatedPage implements Deco
         AdvancedListBox toolbar = new AdvancedListBox();
 
         if (world.getGameVersion() != null && world.getGameVersion().isAtLeast("1.20", "23w14a")) {
-            toolbar.addNavigationDrawerItem(i18n("version.launch"), SVG.ROCKET_LAUNCH, this::launch, null);
+            toolbar.addNavigationDrawerItem(i18n("version.launch"), SVG.ROCKET_LAUNCH, this::launch, advancedListItem -> advancedListItem.setDisable(isReadOnly()));
             toolbar.addNavigationDrawerItem(i18n("version.launch_script"), SVG.SCRIPT, this::generateLaunchScript, null);
         }
 
         if (ChunkBaseApp.isSupported(world)) {
-            PopupMenu popupMenu = new PopupMenu();
+            PopupMenu chunkBasePopupMenu = new PopupMenu();
-            JFXPopup popup = new JFXPopup(popupMenu);
+            JFXPopup chunkBasePopup = new JFXPopup(chunkBasePopupMenu);
 
-            popupMenu.getContent().addAll(
+
-                    new IconedMenuItem(SVG.EXPLORE, i18n("world.chunkbase.seed_map"), () -> ChunkBaseApp.openSeedMap(world), popup),
+            chunkBasePopupMenu.getContent().addAll(
-                    new IconedMenuItem(SVG.VISIBILITY, i18n("world.chunkbase.stronghold"), () -> ChunkBaseApp.openStrongholdFinder(world), popup),
+                    new IconedMenuItem(SVG.EXPLORE, i18n("world.chunkbase.seed_map"), () -> ChunkBaseApp.openSeedMap(world), chunkBasePopup),
-                    new IconedMenuItem(SVG.FORT, i18n("world.chunkbase.nether_fortress"), () -> ChunkBaseApp.openNetherFortressFinder(world), popup)
+                    new IconedMenuItem(SVG.VISIBILITY, i18n("world.chunkbase.stronghold"), () -> ChunkBaseApp.openStrongholdFinder(world), chunkBasePopup),
+                    new IconedMenuItem(SVG.FORT, i18n("world.chunkbase.nether_fortress"), () -> ChunkBaseApp.openNetherFortressFinder(world), chunkBasePopup)
             );
 
             if (world.getGameVersion() != null && world.getGameVersion().compareTo("1.13") >= 0) {
-                popupMenu.getContent().add(
+                chunkBasePopupMenu.getContent().add(
-                        new IconedMenuItem(SVG.LOCATION_CITY, i18n("world.chunkbase.end_city"), () -> ChunkBaseApp.openEndCityFinder(world), popup));
+                        new IconedMenuItem(SVG.LOCATION_CITY, i18n("world.chunkbase.end_city"), () -> ChunkBaseApp.openEndCityFinder(world), chunkBasePopup));
             }
 
             toolbar.addNavigationDrawerItem(i18n("world.chunkbase"), SVG.EXPLORE, null, chunkBaseMenuItem ->
                     chunkBaseMenuItem.setOnAction(e ->
-                            popup.show(chunkBaseMenuItem,
+                            chunkBasePopup.show(chunkBaseMenuItem,
                                     JFXPopup.PopupVPosition.BOTTOM, JFXPopup.PopupHPosition.LEFT,
                                     chunkBaseMenuItem.getWidth(), 0)));
         }
+
         toolbar.addNavigationDrawerItem(i18n("settings.game.exploration"), SVG.FOLDER_OPEN, () -> FXUtils.openFolder(world.getFile()), null);
 
+        {
+            PopupMenu managePopupMenu = new PopupMenu();
+            JFXPopup managePopup = new JFXPopup(managePopupMenu);
+
+            managePopupMenu.getContent().addAll(
+                    new IconedMenuItem(SVG.OUTPUT, i18n("world.export"), () -> WorldManageUIUtils.export(world, sessionLockChannel), managePopup),
+                    new IconedMenuItem(SVG.DELETE, i18n("world.delete"), () -> WorldManageUIUtils.delete(world, () -> fireEvent(new PageCloseEvent()), sessionLockChannel), managePopup),
+                    new IconedMenuItem(SVG.CONTENT_COPY, i18n("world.duplicate"), () -> WorldManageUIUtils.copyWorld(world, null), managePopup)
+            );
+
+            toolbar.addNavigationDrawerItem(i18n("settings.game.management"), SVG.MENU, null, managePopupMenuItem ->
+            {
+                managePopupMenuItem.setOnAction(e ->
+                        managePopup.show(managePopupMenuItem,
+                                JFXPopup.PopupVPosition.BOTTOM, JFXPopup.PopupHPosition.LEFT,
+                                managePopupMenuItem.getWidth(), 0));
+                managePopupMenuItem.setDisable(isReadOnly());
+            });
+
+        }
+
         BorderPane.setMargin(toolbar, new Insets(0, 0, 12, 0));
         left.setBottom(toolbar);
 
         this.addEventHandler(Navigator.NavigationEvent.EXITED, this::onExited);
+        this.addEventHandler(Navigator.NavigationEvent.NAVIGATED, this::onNavigated);
+    }
+
+    private void onNavigated(Navigator.NavigationEvent event) {
+        if (loadFailed) {
+            Platform.runLater(() -> {
+                fireEvent(new PageCloseEvent());
+                Controllers.dialog(i18n("world.load.fail"), null, MessageDialogPane.MessageType.ERROR);
+            });
+            return;
+        }
+        if (sessionLockChannel == null || !sessionLockChannel.isOpen()) {
+            sessionLockChannel = WorldManageUIUtils.getSessionLockChannel(world);
+        }
+    }
+
+    public void onExited(Navigator.NavigationEvent event) {
+        try {
+            WorldManageUIUtils.closeSessionLockChannel(world, sessionLockChannel);
+        } catch (IOException ignored) {
+        }
     }
 
     @Override
@@ -156,19 +205,6 @@ public final class WorldManagePage extends DecoratorAnimatedPage implements Deco
         return sessionLockChannel == null;
     }
 
-    public void onExited(Navigator.NavigationEvent event) {
-        if (sessionLockChannel != null) {
-            try {
-                sessionLockChannel.close();
-                LOG.info("Releases the lock on world " + world.getFileName());
-            } catch (IOException e) {
-                LOG.warning("Failed to close session lock channel", e);
-            }
-
-            sessionLockChannel = null;
-        }
-    }
-
     public void launch() {
         fireEvent(new PageCloseEvent());
         Versions.launchAndEnterWorld(profile, id, world.getFileName());

HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldManageUIUtils.java

@@ -0,0 +1,152 @@
+/*
+ * Hello Minecraft! Launcher
+ * Copyright (C) 2025  huangyuhui <huanghongxun2008@126.com> and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.jackhuang.hmcl.ui.versions;
+
+import javafx.stage.FileChooser;
+import org.jackhuang.hmcl.game.World;
+import org.jackhuang.hmcl.game.WorldLockedException;
+import org.jackhuang.hmcl.task.Schedulers;
+import org.jackhuang.hmcl.task.Task;
+import org.jackhuang.hmcl.ui.Controllers;
+import org.jackhuang.hmcl.ui.construct.InputDialogPane;
+import org.jackhuang.hmcl.ui.construct.MessageDialogPane;
+import org.jackhuang.hmcl.ui.wizard.SinglePageWizardProvider;
+import org.jackhuang.hmcl.util.StringUtils;
+import org.jackhuang.hmcl.util.io.FileUtils;
+
+import java.io.IOException;
+import java.nio.channels.FileChannel;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.jackhuang.hmcl.util.i18n.I18n.i18n;
+import static org.jackhuang.hmcl.util.logging.Logger.LOG;
+
+public final class WorldManageUIUtils {
+    private WorldManageUIUtils() {
+    }
+
+    public static void delete(World world, Runnable runnable) {
+        delete(world, runnable, null);
+    }
+
+    public static void delete(World world, Runnable runnable, FileChannel sessionLockChannel) {
+        Controllers.confirm(
+                i18n("button.remove.confirm"),
+                i18n("world.delete"),
+                () -> Task.runAsync(() -> closeSessionLockChannel(world, sessionLockChannel))
+                        .thenRunAsync(world::delete)
+                        .whenComplete(Schedulers.javafx(), (result, exception) -> {
+                            if (exception == null) {
+                                runnable.run();
+                            } else if (exception instanceof WorldLockedException) {
+                                Controllers.dialog(i18n("world.locked.failed"), null, MessageDialogPane.MessageType.WARNING);
+                            } else {
+                                Controllers.dialog(i18n("world.delete.failed", StringUtils.getStackTrace(exception)), null, MessageDialogPane.MessageType.WARNING);
+                            }
+                        }).start(),
+                null
+        );
+    }
+
+    public static void export(World world) {
+        export(world, null);
+    }
+
+    public static void export(World world, FileChannel sessionLockChannel) {
+        FileChooser fileChooser = new FileChooser();
+        fileChooser.setTitle(i18n("world.export.title"));
+        fileChooser.getExtensionFilters().add(new FileChooser.ExtensionFilter(i18n("world"), "*.zip"));
+        fileChooser.setInitialFileName(world.getWorldName());
+        Path file = FileUtils.toPath(fileChooser.showSaveDialog(Controllers.getStage()));
+        if (file == null) {
+            return;
+        }
+
+        try {
+            closeSessionLockChannel(world, sessionLockChannel);
+        } catch (IOException e) {
+            return;
+        }
+
+        Controllers.getDecorator().startWizard(new SinglePageWizardProvider(controller -> new WorldExportPage(world, file, controller::onFinish)));
+    }
+
+    public static void copyWorld(World world, Runnable runnable) {
+        Path worldPath = world.getFile();
+        Controllers.dialog(new InputDialogPane(
+                i18n("world.duplicate.prompt"),
+                "",
+                (result, resolve, reject) -> {
+                    if (StringUtils.isBlank(result)) {
+                        reject.accept(i18n("world.duplicate.failed.empty_name"));
+                        return;
+                    }
+
+                    if (result.contains("/") || result.contains("\\") || !FileUtils.isNameValid(result)) {
+                        reject.accept(i18n("world.duplicate.failed.invalid_name"));
+                        return;
+                    }
+
+                    Path targetDir = worldPath.resolveSibling(result);
+                    if (Files.exists(targetDir)) {
+                        reject.accept(i18n("world.duplicate.failed.already_exists"));
+                        return;
+                    }
+
+                    Task.runAsync(Schedulers.io(), () -> world.copy(result))
+                            .thenAcceptAsync(Schedulers.javafx(), (Void) -> Controllers.showToast(i18n("world.duplicate.success.toast")))
+                            .thenAcceptAsync(Schedulers.javafx(), (Void) -> {
+                                        if (runnable != null) {
+                                            runnable.run();
+                                        }
+                                    }
+                            ).whenComplete(Schedulers.javafx(), (throwable) -> {
+                                if (throwable == null) {
+                                    resolve.run();
+                                } else {
+                                    reject.accept(i18n("world.duplicate.failed"));
+                                    LOG.warning("Failed to duplicate world " + world.getFile(), throwable);
+                                }
+                            })
+                            .start();
+                }));
+    }
+
+    public static void closeSessionLockChannel(World world, FileChannel sessionLockChannel) throws IOException {
+        if (sessionLockChannel != null) {
+            try {
+                sessionLockChannel.close();
+                LOG.info("Closed session lock channel of the world " + world.getFileName());
+            } catch (IOException e) {
+                throw new IOException("Failed to close session lock channel of the world " + world.getFile(), e);
+            }
+        }
+    }
+
+    public static FileChannel getSessionLockChannel(World world) {
+        try {
+            FileChannel lock = world.lock();
+            LOG.info("Acquired lock on world " + world.getFileName());
+            return lock;
+        } catch (IOException ignored) {
+            return null;
+        }
+    }
+
+}

HMCL/src/main/resources/assets/lang/I18N.properties

@@ -1131,6 +1131,13 @@ world.chunkbase.end_city=End City
 world.chunkbase.seed_map=Seed Map
 world.chunkbase.stronghold=Stronghold
 world.chunkbase.nether_fortress=Nether Fortress
+world.duplicate=Duplicate the World
+world.duplicate.prompt=Please enter the name of the duplicated world
+world.duplicate.failed.already_exists=Directory already exists
+world.duplicate.failed.empty_name=Name cannot be empty
+world.duplicate.failed.invalid_name=Name contains invalid characters
+world.duplicate.failed=Failed to duplicate the world
+world.duplicate.success.toast=Successfully duplicated the world
 world.datapack=Datapacks
 world.datetime=Last played on %s
 world.delete=Delete the World
@@ -1143,6 +1150,15 @@ world.export.location=Save As
 world.export.wizard=Export World "%s"
 world.extension=World Archive
 world.game_version=Game Version
+world.icon=World Icon
+world.icon.change=Change world icon
+world.icon.change.fail.load.title=Failed to parse image
+world.icon.change.fail.load.text=This image appears to be corrupted, and HMCL cannot parse it.
+world.icon.change.fail.not_64x64.title=Image size error
+world.icon.change.fail.not_64x64.text=The image resolution is %d×%d instead of 64×64. Please provide a 64×64 image and try again.
+world.icon.change.succeed.toast=Successfully updated the world icon.
+world.icon.change.tip=A 64×64 PNG image is required. Images with an incorrect resolution cannot be parsed by Minecraft.
+world.icon.choose.title=Select world icon
 world.import.already_exists=This world already exists.
 world.import.choose=Choose world archive you want to import
 world.import.failed=Failed to import this world: %s
@@ -1157,6 +1173,7 @@ world.info.difficulty.peaceful=Peaceful
 world.info.difficulty.easy=Easy
 world.info.difficulty.normal=Normal
 world.info.difficulty.hard=Hard
+world.info.difficulty_lock=Lock Difficulty
 world.info.failed=Failed to read the world info
 world.info.game_version=Game Version
 world.info.last_played=Last Played
@@ -1177,6 +1194,7 @@ world.info.player.xp_level=Experience Level
 world.info.random_seed=Seed
 world.info.time=Game Time
 world.info.time.format=%s days
+world.load.fail=Failed to load world
 world.locked=In use
 world.locked.failed=The world is currently in use. Please close the game and try again.
 world.manage=Worlds

HMCL/src/main/resources/assets/lang/I18N_es.properties

@@ -1111,6 +1111,9 @@ world.chunkbase.end_city=Ciudad del End
 world.chunkbase.seed_map=Vista previa de la generación mundial
 world.chunkbase.stronghold=Fortaleza
 world.chunkbase.nether_fortress=Fortaleza del Nether
+world.duplicate.failed.already_exists=El directorio ya existe
+world.duplicate.failed.empty_name=El nombre no puede estar vacío
+world.duplicate.failed.invalid_name=El nombre contiene caracteres no válidos
 world.datapack=Paquetes de datos
 world.datetime=Jugado por última vez en %s
 world.delete=Eliminar este mundo

HMCL/src/main/resources/assets/lang/I18N_ru.properties

@@ -1104,6 +1104,9 @@ world.chunkbase.end_city=Город Края
 world.chunkbase.seed_map=Предпросмотр генерации мира
 world.chunkbase.stronghold=Крепость
 world.chunkbase.nether_fortress=Крепость Нижнего мира
+world.duplicate.failed.already_exists=Папка уже существует
+world.duplicate.failed.empty_name=Название не может быть пустым
+world.duplicate.failed.invalid_name=Название содержит недопустимые символы
 world.delete=Удалить этот мир
 world.delete.failed=Не удалось удалить мир.\n%s
 world.datapack=Наборы данных

HMCL/src/main/resources/assets/lang/I18N_uk.properties

@@ -1048,6 +1048,9 @@ world.chunkbase.end_city=Кінцеве місто
 world.chunkbase.seed_map=Карта насіння
 world.chunkbase.stronghold=Фортеця
 world.chunkbase.nether_fortress=Форт Незеру
+world.duplicate.failed.already_exists=Каталог вже існує
+world.duplicate.failed.empty_name=Назва не може бути порожньою
+world.duplicate.failed.invalid_name=Назва містить недійсні символи
 world.datapack=Datapacks
 world.datetime=Останній раз грали %s
 world.delete=Видалити цей світ

HMCL/src/main/resources/assets/lang/I18N_zh.properties

@@ -919,6 +919,13 @@ world.chunkbase.end_city=終界城地圖
 world.chunkbase.seed_map=種子地圖
 world.chunkbase.stronghold=要塞地圖
 world.chunkbase.nether_fortress=地獄要塞地圖
+world.duplicate=複製此世界
+world.duplicate.prompt=輸入複製後的世界名稱
+world.duplicate.failed.already_exists=目錄已存在
+world.duplicate.failed.empty_name=名稱不能為空
+world.duplicate.failed.invalid_name=名稱中包含無效字元
+world.duplicate.failed=複製世界失敗
+world.duplicate.success.toast=複製世界成功
 world.datapack=資料包管理
 world.datetime=上一次遊戲時間: %s
 world.delete=刪除此世界
@@ -930,6 +937,15 @@ world.export.title=選取該世界的儲存位置
 world.export.location=儲存到
 world.export.wizard=匯出世界「%s」
 world.extension=世界壓縮檔
+world.icon=世界圖示
+world.icon.change=修改世界圖示
+world.icon.change.fail.load.title=圖片解析失敗
+world.icon.change.fail.load.text=該圖片似乎已損毀，HMCL 無法解析它
+world.icon.change.fail.not_64x64.title=圖片大小錯誤
+world.icon.change.fail.not_64x64.text=該圖片的解析度為 %d×%d，而不是 64×64，請提供一張 64×64 解析度的圖片再次嘗試
+world.icon.change.succeed.toast=世界圖示修改成功
+world.icon.change.tip=請提供一張 64×64 PNG 格式的圖片。錯誤解析度的圖片將無法被 Minecraft 解析。
+world.icon.choose.title=選擇世界圖示
 world.import.already_exists=此世界已經存在
 world.import.choose=選取要匯入的世界壓縮檔
 world.import.failed=無法匯入此世界: %s
@@ -944,6 +960,7 @@ world.info.difficulty.peaceful=和平
 world.info.difficulty.easy=簡單
 world.info.difficulty.normal=普通
 world.info.difficulty.hard=困難
+world.info.difficulty_lock=鎖定難易度
 world.info.failed=讀取世界資訊失敗
 world.info.game_version=遊戲版本
 world.info.last_played=上一次遊戲時間
@@ -964,6 +981,7 @@ world.info.player.xp_level=經驗等級
 world.info.random_seed=種子碼
 world.info.time=遊戲內時間
 world.info.time.format=%s 天
+world.load.fail=世界載入失敗
 world.locked=使用中
 world.locked.failed=該世界正在使用中，請關閉遊戲後重試。
 world.game_version=遊戲版本

HMCL/src/main/resources/assets/lang/I18N_zh_CN.properties

@@ -923,6 +923,13 @@ world.chunkbase.end_city=末地城地图
 world.chunkbase.seed_map=种子地图
 world.chunkbase.stronghold=要塞地图
 world.chunkbase.nether_fortress=下界要塞地图
+world.duplicate=复制此世界
+world.duplicate.prompt=输入复制后的世界名称
+world.duplicate.failed.already_exists=文件夹已存在
+world.duplicate.failed.empty_name=名称不能为空
+world.duplicate.failed.invalid_name=名称中包含非法字符
+world.duplicate.failed=复制世界失败
+world.duplicate.success.toast=复制世界成功
 world.datapack=数据包管理
 world.datetime=上一次游戏时间: %s
 world.delete=删除此世界
@@ -935,6 +942,15 @@ world.export.location=保存到
 world.export.wizard=导出世界“%s”
 world.extension=世界压缩包
 world.game_version=游戏版本
+world.icon=世界图标
+world.icon.change=修改世界图标
+world.icon.change.fail.load.title=图片解析出错
+world.icon.change.fail.load.text=该图片似乎已损坏，HMCL 无法解析它
+world.icon.change.fail.not_64x64.title=图片大小错误
+world.icon.change.fail.not_64x64.text=该图片的分辨率为 %d×%d，而不是 64×64，请提供一张 64×64 分辨率的图片再次尝试
+world.icon.change.succeed.toast=世界图标修改成功
+world.icon.change.tip=请提供一张 64×64 PNG 格式的图片。错误分辨率的图片将无法被 Minecraft 解析。
+world.icon.choose.title=选择世界图标
 world.import.already_exists=此世界已经存在
 world.import.choose=选择要导入的世界压缩包
 world.import.failed=无法导入此世界：%s
@@ -949,6 +965,7 @@ world.info.difficulty.peaceful=和平
 world.info.difficulty.easy=简单
 world.info.difficulty.normal=普通
 world.info.difficulty.hard=困难
+world.info.difficulty_lock=锁定难度
 world.info.failed=读取世界信息失败
 world.info.game_version=游戏版本
 world.info.last_played=上一次游戏时间
@@ -969,6 +986,7 @@ world.info.player.xp_level=经验等级
 world.info.random_seed=种子
 world.info.time=游戏内时间
 world.info.time.format=%s 天
+world.load.fail=世界加载失败
 world.locked=使用中
 world.locked.failed=该世界正在使用中，请关闭游戏后重试。
 world.manage=世界管理

HMCLCore/src/main/java/org/jackhuang/hmcl/game/World.java

@@ -18,10 +18,7 @@
 package org.jackhuang.hmcl.game;
 
 import com.github.steveice10.opennbt.NBTIO;
-import com.github.steveice10.opennbt.tag.builtin.CompoundTag;
+import com.github.steveice10.opennbt.tag.builtin.*;
-import com.github.steveice10.opennbt.tag.builtin.LongTag;
-import com.github.steveice10.opennbt.tag.builtin.StringTag;
-import com.github.steveice10.opennbt.tag.builtin.Tag;
 import javafx.scene.image.Image;
 import org.jackhuang.hmcl.util.io.*;
 import org.jackhuang.hmcl.util.versioning.GameVersionNumber;
@@ -48,13 +45,10 @@ public final class World {
 
     private final Path file;
     private String fileName;
-    private String worldName;
+    private CompoundTag levelData;
-    private GameVersionNumber gameVersion;
-    private long lastPlayed;
     private Image icon;
-    private Long seed;
-    private boolean largeBiomes;
     private boolean isLocked;
+    private Path levelDataPath;
 
     public World(Path file) throws IOException {
         this.file = file;
@@ -67,10 +61,100 @@ public final class World {
             throw new IOException("Path " + file + " cannot be recognized as a Minecraft world");
     }
 
+    public Path getFile() {
+        return file;
+    }
+
+    public String getFileName() {
+        return fileName;
+    }
+
+    public String getWorldName() {
+        CompoundTag data = levelData.get("Data");
+        StringTag levelNameTag = data.get("LevelName");
+        return levelNameTag.getValue();
+    }
+
+    public void setWorldName(String worldName) throws IOException {
+        if (levelData.get("Data") instanceof CompoundTag data && data.get("LevelName") instanceof StringTag levelNameTag) {
+            levelNameTag.setValue(worldName);
+            writeLevelDat(levelData);
+        }
+    }
+
+    public Path getLevelDatFile() {
+        return file.resolve("level.dat");
+    }
+
+    public Path getSessionLockFile() {
+        return file.resolve("session.lock");
+    }
+
+    public CompoundTag getLevelData() {
+        return levelData;
+    }
+
+    public long getLastPlayed() {
+        CompoundTag data = levelData.get("Data");
+        LongTag lastPlayedTag = data.get("LastPlayed");
+        return lastPlayedTag.getValue();
+    }
+
+    public @Nullable GameVersionNumber getGameVersion() {
+        if (levelData.get("Data") instanceof CompoundTag data &&
+                data.get("Version") instanceof CompoundTag versionTag &&
+                versionTag.get("Name") instanceof StringTag nameTag) {
+            return GameVersionNumber.asGameVersion(nameTag.getValue());
+        }
+        return null;
+    }
+
+    public @Nullable Long getSeed() {
+        CompoundTag data = levelData.get("Data");
+        if (data.get("WorldGenSettings") instanceof CompoundTag worldGenSettingsTag && worldGenSettingsTag.get("seed") instanceof LongTag seedTag) { //Valid after 1.16
+            return seedTag.getValue();
+        } else if (data.get("RandomSeed") instanceof LongTag seedTag) { //Valid before 1.16
+            return seedTag.getValue();
+        }
+        return null;
+    }
+
+    public boolean isLargeBiomes() {
+        CompoundTag data = levelData.get("Data");
+        if (data.get("generatorName") instanceof StringTag generatorNameTag) { //Valid before 1.16
+            return "largeBiomes".equals(generatorNameTag.getValue());
+        } else {
+            if (data.get("WorldGenSettings") instanceof CompoundTag worldGenSettingsTag
+                    && worldGenSettingsTag.get("dimensions") instanceof CompoundTag dimensionsTag
+                    && dimensionsTag.get("minecraft:overworld") instanceof CompoundTag overworldTag
+                    && overworldTag.get("generator") instanceof CompoundTag generatorTag) {
+                if (generatorTag.get("biome_source") instanceof CompoundTag biomeSourceTag
+                        && biomeSourceTag.get("large_biomes") instanceof ByteTag largeBiomesTag) { //Valid between 1.16 and 1.16.2
+                    return largeBiomesTag.getValue() == (byte) 1;
+                } else if (generatorTag.get("settings") instanceof StringTag settingsTag) { //Valid after 1.16.2
+                    return "minecraft:large_biomes".equals(settingsTag.getValue());
+                }
+            }
+            return false;
+        }
+    }
+
+    public Image getIcon() {
+        return icon;
+    }
+
+    public boolean isLocked() {
+        return isLocked;
+    }
+
     private void loadFromDirectory() throws IOException {
         fileName = FileUtils.getName(file);
         Path levelDat = file.resolve("level.dat");
-        loadWorldInfo(levelDat);
+        if (!Files.exists(levelDat)) { // version 20w14infinite
+            levelDat = file.resolve("special_level.dat");
+        }
+        loadAndCheckLevelDat(levelDat);
+        this.levelDataPath = levelDat;
         isLocked = isLocked(getSessionLockFile());
 
         Path iconFile = file.resolve("icon.png");
@@ -85,56 +169,16 @@ public final class World {
         }
     }
 
-    public Path getFile() {
-        return file;
-    }
-
-    public String getFileName() {
-        return fileName;
-    }
-
-    public String getWorldName() {
-        return worldName;
-    }
-
-    public Path getLevelDatFile() {
-        return file.resolve("level.dat");
-    }
-
-    public Path getSessionLockFile() {
-        return file.resolve("session.lock");
-    }
-
-    public long getLastPlayed() {
-        return lastPlayed;
-    }
-
-    public @Nullable GameVersionNumber getGameVersion() {
-        return gameVersion;
-    }
-
-    public @Nullable Long getSeed() {
-        return seed;
-    }
-
-    public boolean isLargeBiomes() {
-        return largeBiomes;
-    }
-
-    public Image getIcon() {
-        return icon;
-    }
-
-    public boolean isLocked() {
-        return isLocked;
-    }
-
     private void loadFromZipImpl(Path root) throws IOException {
         Path levelDat = root.resolve("level.dat");
-        if (!Files.exists(levelDat))
+        if (!Files.exists(levelDat)) { //version 20w14infinite
-            throw new IOException("Not a valid world zip file since level.dat cannot be found.");
+            levelDat = root.resolve("special_level.dat");
+        }
+        if (!Files.exists(levelDat)) {
+            throw new IOException("Not a valid world zip file since level.dat or special_level.dat cannot be found.");
+        }
 
-        loadWorldInfo(levelDat);
+        loadAndCheckLevelDat(levelDat);
 
         Path iconFile = root.resolve("icon.png");
         if (Files.isRegularFile(iconFile)) {
@@ -167,50 +211,22 @@ public final class World {
         }
     }
 
-    private void loadWorldInfo(Path levelDat) throws IOException {
+    private void loadAndCheckLevelDat(Path levelDat) throws IOException {
-        CompoundTag nbt = parseLevelDat(levelDat);
+        this.levelData = parseLevelDat(levelDat);
-
+        CompoundTag data = levelData.get("Data");
-        CompoundTag data = nbt.get("Data");
         if (data == null)
             throw new IOException("level.dat missing Data");
 
-        if (data.get("LevelName") instanceof StringTag)
+        if (!(data.get("LevelName") instanceof StringTag))
-            worldName = data.<StringTag>get("LevelName").getValue();
-        else
             throw new IOException("level.dat missing LevelName");
 
-        if (data.get("LastPlayed") instanceof LongTag)
+        if (!(data.get("LastPlayed") instanceof LongTag))
-            lastPlayed = data.<LongTag>get("LastPlayed").getValue();
-        else
             throw new IOException("level.dat missing LastPlayed");
-
-        gameVersion = null;
-        if (data.get("Version") instanceof CompoundTag) {
-            CompoundTag version = data.get("Version");
-
-            if (version.get("Name") instanceof StringTag)
-                gameVersion = GameVersionNumber.asGameVersion(version.<StringTag>get("Name").getValue());
     }
 
-        Tag worldGenSettings = data.get("WorldGenSettings");
+    public void reloadLevelDat() throws IOException {
-        if (worldGenSettings instanceof CompoundTag) {
+        if (levelDataPath != null) {
-            Tag seedTag = ((CompoundTag) worldGenSettings).get("seed");
+            loadAndCheckLevelDat(this.levelDataPath);
-            if (seedTag instanceof LongTag) {
-                seed = ((LongTag) seedTag).getValue();
-            }
-        }
-        if (seed == null) {
-            Tag seedTag = data.get("RandomSeed");
-            if (seedTag instanceof LongTag) {
-                seed = ((LongTag) seedTag).getValue();
-            }
-        }
-
-        // FIXME: Only work for 1.15 and below
-        if (data.get("generatorName") instanceof StringTag) {
-            largeBiomes = "largeBiomes".equals(data.<StringTag>get("generatorName").getValue());
-        } else {
-            largeBiomes = false;
         }
     }
 
@@ -219,10 +235,9 @@ public final class World {
             throw new IOException("Not a valid world directory");
 
         // Change the name recorded in level.dat
-        CompoundTag nbt = readLevelDat();
+        CompoundTag data = levelData.get("Data");
-        CompoundTag data = nbt.get("Data");
         data.put(new StringTag("LevelName", newName));
-        writeLevelDat(nbt);
+        writeLevelDat(levelData);
 
         // then change the folder's name
         Files.move(file, file.resolveSibling(newName));
@@ -283,11 +298,19 @@ public final class World {
         FileUtils.forceDelete(file);
     }
 
-    public CompoundTag readLevelDat() throws IOException {
+    public void copy(String newName) throws IOException {
-        if (!Files.isDirectory(file))
+        if (!Files.isDirectory(file)) {
             throw new IOException("Not a valid world directory");
+        }
 
-        return parseLevelDat(getLevelDatFile());
+        if (isLocked()) {
+            throw new WorldLockedException("The world " + getFile() + " has been locked");
+        }
+
+        Path newPath = file.resolveSibling(newName);
+        FileUtils.copyDirectory(file, newPath, path -> !path.contains("session.lock"));
+        World newWorld = new World(newPath);
+        newWorld.rename(newName);
     }
 
     public FileChannel lock() throws WorldLockedException {