Refactoring 2

.idea/encodings.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding">
+    <file url="file://$PROJECT_DIR$/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/src/main/resources" charset="UTF-8" />
+  </component>
+</project>

.idea/misc.xml

@@ -8,7 +8,7 @@
       </list>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" default="true" project-jdk-name="temurin-11" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_17" default="true" project-jdk-name="temurin-17" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/classes" />
   </component>
 </project>

README.md

@@ -2,10 +2,28 @@
 
 This plugin adds naturally spawning Giants with AI to your Minecraft server.
 
-### Requested features
-- Texture variation \
-  I think this can be done, but would require a texture pack
-- Boss bar \
-  I don't want to get buried in that, so this would require an API, which, for performance reasons, should not be mandatory
-- Hitboxes \
-  I don't know if this is still a major issue, but a person reported that the hitbox doesn't cover the whole body
+### Signing
+Public key goes into `resources/verifies_downloaded_jars.pem`
+
+A default keystore is not provided.
+
+To create a keystore and export public key:
+```
+keytool -keystore testkeystore2.jks -genkeypair -keyalg RSA -alias testkey -validity 999999
+keytool -exportcert -alias testkey -keystore testkeystore2.jks -file cert.cer -rfc
+openssl x509 -inform pem -in cert.cer -pubkey -noout > public_key.pem
+```
+
+When using `mvn`, override with `-Djarsigner.`
+```
+mvn clean package -Djarsigner.keystore=/home/user/mykeystore.jks -Djarsigner.alias=mykey
+```
+
+### Color scheme
+The following color scheme is used for chat messages:
+- Errors: RED
+- "Soft errors" (like no permission): GRAY
+- Status messages: GRAY
+- Notice / call for action: YELLOW (optionally also BOLD)
+- Information: GOLD
+- Highlight: AQUA (TODO do that)

pom.xml

@@ -2,11 +2,15 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>eu.m724</groupId>
   <artifactId>giants</artifactId>
-  <version>2.0.5</version>
+  <version>2.0.12-SNAPSHOT</version>
 
   <properties>
-    <maven.compiler.source>11</maven.compiler.source>
-    <maven.compiler.target>11</maven.compiler.target>
+    <maven.compiler.release>17</maven.compiler.release>
+    <jarsigner.keystore>${project.basedir}/keystore.jks</jarsigner.keystore>
+    <jarsigner.alias>mykey</jarsigner.alias>
+    <jarsigner.storepass>123456</jarsigner.storepass>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
   </properties>
 
   <repositories>
@@ -42,12 +46,19 @@
         </exclusion>
       </exclusions>
     </dependency>
+
     <dependency>
       <groupId>org.bstats</groupId>
       <artifactId>bstats-bukkit</artifactId>
       <version>3.0.2</version>
       <scope>compile</scope>
     </dependency>
+
+    <dependency>
+      <groupId>eu.m724</groupId>
+      <artifactId>jarupdater</artifactId>
+      <version>0.1.10</version>
+    </dependency>
   </dependencies>
 
   <build>
@@ -72,15 +83,30 @@
         <version>3.6.0</version>
         <configuration>
           <createDependencyReducedPom>false</createDependencyReducedPom>
-          <shadedArtifactAttached>true</shadedArtifactAttached>
-          <shadedClassifierName>full</shadedClassifierName>
+          <minimizeJar>true</minimizeJar>
+          <!-- <shadedArtifactAttached>true</shadedArtifactAttached>
+          <shadedClassifierName>full</shadedClassifierName> -->
           <relocations>
             <relocation>
               <pattern>org.bstats</pattern>
-              <!-- Replace this with your package! -->
               <shadedPattern>eu.m724.giants</shadedPattern>
             </relocation>
           </relocations>
+          <artifactSet>
+            <includes>
+              <include>org.bstats:*</include>
+              <include>eu.m724:jarupdater</include>
+            </includes>
+          </artifactSet>
+          <filters>
+            <filter>
+              <artifact>*</artifact>
+              <excludes>
+                <exclude>META-INF/MANIFEST.MF</exclude>
+                <exclude>META-INF/maven/**</exclude>
+              </excludes>
+            </filter>
+          </filters>
         </configuration>
         <executions>
           <execution>
@@ -91,13 +117,37 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-jarsigner-plugin</artifactId>
+        <version>3.1.0</version>
+        <executions>
+          <execution>
+            <id>sign</id>
+            <goals>
+              <goal>sign</goal>
+            </goals>
+          </execution>
+          <execution>
+            <id>verify</id>
+            <goals>
+              <goal>verify</goal>
+            </goals>
+          </execution>
+        </executions>
+        <configuration>
+          <keystore>${jarsigner.keystore}</keystore>
+          <alias>${jarsigner.alias}</alias>
+          <storepass>${jarsigner.storepass}</storepass>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 
 
   <scm>
     <developerConnection>scm:git:git@git.m724.eu:Minecon724/giants.git</developerConnection>
-    <tag>giants-2.0.5</tag>
+    <tag>HEAD</tag>
   </scm>
 
   <distributionManagement>

src/main/java/eu/m724/giants/Configuration.java

@@ -1,130 +0,0 @@
-package eu.m724.giants;
-
-import org.bukkit.Material;
-import org.bukkit.configuration.file.YamlConfiguration;
-import org.bukkit.inventory.ItemStack;
-import org.bukkit.plugin.Plugin;
-import org.bukkit.potion.PotionEffect;
-import org.bukkit.potion.PotionEffectType;
-import org.bukkit.util.Vector;
-
-import java.io.File;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.logging.Logger;
-
-public class Configuration {
-    private final File file;
-    private final Logger logger;
-
-    boolean ai;
-
-    double attackDamage;
-    int attackDelay;
-    Vector attackReach;
-    int jumpMode;
-    int jumpCondition;
-    int jumpDelay;
-    double jumpHeight = -1;
-
-    double chance;
-    List<String> worldBlacklist;
-    Set<PotionEffect> effects = new HashSet<>();
-    Set<Drop> drops = new HashSet<>();
-
-    public Configuration(Plugin plugin, File file) {
-        this.file = file;
-        this.logger = Logger.getLogger(plugin.getLogger().getName() + ".Configuration");
-    }
-
-    public void load() {
-        YamlConfiguration config = YamlConfiguration.loadConfiguration(file);
-
-        ai = config.getBoolean("ai");
-
-        chance = config.getDouble("chance");
-        attackDamage = config.getDouble("attackDamage");
-        attackDelay = config.getInt("attackDelay");
-        jumpMode = config.getInt("jumpMode");
-        jumpCondition = config.getInt("jumpCondition");
-        jumpDelay = config.getInt("jumpDelay");
-
-        if (jumpMode != 0) {
-            jumpHeight = config.getDouble("jumpHeight", -1);
-            if (jumpHeight == -1) {
-                jumpHeight = defaultJumpHeight();
-            }
-            logger.info("Jumping is experimental.");
-            logger.info("Jump mode: " + jumpMode);
-            logger.info("Jump condition: " + jumpCondition);
-            logger.info("Jump height: " + jumpHeight);
-        }
-
-        double _attackReach = config.getDouble("attackReach");
-        double _attackVerticalReach = config.getDouble("attackVerticalReach");
-        attackReach = new Vector(_attackReach, _attackVerticalReach, _attackReach);
-
-        worldBlacklist = config.getStringList("blacklist");
-
-        for (String line : config.getStringList("effects")) {
-            String[] parts = line.split(":");
-
-            try {
-                PotionEffectType effectType = PotionEffectType.getByName(parts[0]);
-                if (effectType == null) {
-                    throw new IllegalArgumentException("Invalid PotionEffectType");
-                }
-                int amplifier = Integer.parseInt(parts[1]);
-                effects.add(new PotionEffect(effectType, Integer.MAX_VALUE, amplifier));
-            } catch (IllegalArgumentException e) {
-                logger.warning("Parsing a potion effect failed:");
-                logger.warning(line);
-                logger.warning(e.getMessage());
-            }
-        }
-
-        for (Map<?, ?> dropMap : config.getMapList("drops")) {
-            try {
-                ItemStack itemStack;
-                if (dropMap.containsKey("itemStack")) {
-                    itemStack = (ItemStack) dropMap.get("itemStack");
-                } else {
-                    Material material = Material.getMaterial((String) dropMap.get("material"));
-                    if (material == null) {
-                        throw new IllegalArgumentException("Invalid Material");
-                    }
-                    itemStack = new ItemStack(material, 1);
-                }
-
-                int min = (int) dropMap.get("quantityMin");
-                int max = (int) dropMap.get("quantityMax");
-                double chance;
-                try {
-                    chance = (double) dropMap.get("chance");
-                } catch (ClassCastException e) { // pointlessest error ever
-                    chance = ((Integer) dropMap.get("chance")).doubleValue();
-                }
-
-                drops.add(new Drop(itemStack, min, max, chance));
-            } catch (IllegalArgumentException e) {
-                logger.warning("Parsing a drop failed:");
-                logger.warning(e.getMessage());
-            }
-        }
-    }
-
-    public double defaultJumpHeight() {
-        switch (jumpMode) {
-            case 1:
-            case 2:
-                return 0.42;
-            case 3:
-            case 4:
-                return 1.2;
-        }
-
-        return -1;
-    }
-}

src/main/java/eu/m724/giants/Drop.java

@@ -1,25 +1,34 @@
 package eu.m724.giants;
 
+import org.bukkit.Location;
 import org.bukkit.inventory.ItemStack;
 
 import java.util.concurrent.ThreadLocalRandom;
 
-public class Drop {
-    public final ItemStack itemStack;
-    public final int min, max;
-    public final double chance;
-
-    public Drop(ItemStack itemStack, int min, int max, double chance) {
-        this.itemStack = itemStack;
-        this.min = min;
-        this.max = max;
-        this.chance = chance;
-    }
-
-    public ItemStack generateItemStack() {
+public record Drop(ItemStack itemStack, int min, int max, double chance) {
+    /**
+     * Randomizes quantity and returns {@link ItemStack}.<br>
+     * This should be called every drop.
+     *
+     * @return A {@link ItemStack} with randomized quantity
+     */
+    private ItemStack generate() {
         int amount = ThreadLocalRandom.current().nextInt(min, max + 1);
+
         ItemStack itemStack = this.itemStack.clone();
         itemStack.setAmount(amount);
         return itemStack;
     }
+
+    /**
+     * Drops the item at {@code location} taking into account quantity and chance.
+     *
+     * @param location The location to drop the drop at
+     */
+    public void dropAt(Location location) {
+        if (chance > ThreadLocalRandom.current().nextDouble()) {
+            ItemStack itemStack = generate();
+            location.getWorld().dropItemNaturally(location, itemStack);
+        }
+    }
 }

src/main/java/eu/m724/giants/GiantProcessor.java

@@ -1,234 +0,0 @@
-package eu.m724.giants;
-
-import org.bukkit.Location;
-import org.bukkit.Material;
-import org.bukkit.NamespacedKey;
-import org.bukkit.entity.*;
-import org.bukkit.event.EventHandler;
-import org.bukkit.event.Listener;
-import org.bukkit.event.entity.EntityDeathEvent;
-import org.bukkit.event.entity.EntitySpawnEvent;
-import org.bukkit.event.entity.EntityTargetLivingEntityEvent;
-import org.bukkit.event.world.ChunkLoadEvent;
-import org.bukkit.inventory.ItemStack;
-import org.bukkit.persistence.PersistentDataType;
-import org.bukkit.plugin.java.JavaPlugin;
-import org.bukkit.potion.PotionEffect;
-import org.bukkit.potion.PotionEffectType;
-import org.bukkit.scheduler.BukkitRunnable;
-import org.bukkit.util.Vector;
-
-import java.util.*;
-import java.util.concurrent.ThreadLocalRandom;
-import java.util.logging.Logger;
-
-// TODO move ai stuff to another class
-/**
- * A processor class that processes giants
- */
-public class GiantProcessor implements Listener {
-    private static final int VERSION = 1;
-
-    private final JavaPlugin plugin;
-    private final Configuration configuration;
-    private final Logger logger;
-
-   // private final Set<Giant> trackedGiants = new HashSet<>();
-    private final Set<Husk> trackedHusks = new HashSet<>();
-    private final Map<Entity, Location> giantLocationMap = new HashMap<>();
-    private final Map<Entity, Long> giantLastJump = new HashMap<>();
-
-    private final ThreadLocalRandom random = ThreadLocalRandom.current();
-    private final NamespacedKey huskKey;
-
-    public GiantProcessor(JavaPlugin plugin, Configuration configuration) {
-        this.plugin = plugin;
-        this.configuration = configuration;
-        this.logger = Logger.getLogger(plugin.getLogger().getName() + ".GiantProcessor");
-        this.huskKey = new NamespacedKey(plugin, "husk");
-    }
-
-    void start() {
-        if (configuration.ai) {
-            new BukkitRunnable() {
-                @Override
-                public void run() {
-                    for (Husk husk : Set.copyOf(trackedHusks)) {
-                        if (husk.isValid()) {
-                            Location huskLocation = husk.getLocation();
-                            Entity giant = husk.getVehicle();
-
-                            if (giant instanceof Giant) {
-                                if (giant.isValid()) { // TODO reconsider
-                                    giant.getWorld().getNearbyEntities(
-                                            giant.getBoundingBox().expand(configuration.attackReach),
-                                            e -> (e instanceof Player && !e.isInvulnerable())
-                                    ).forEach(p -> ((Player) p).damage(configuration.attackDamage, giant));
-                                    giant.setRotation(huskLocation.getYaw(), huskLocation.getPitch());
-
-                                    // jumping
-                                    if (configuration.jumpMode != 0) {
-                                        // tracking location is only required for jumping
-                                        Location prevLocation = giantLocationMap.get(giant);
-                                        Location location = giant.getLocation();
-                                        if (prevLocation == null) {
-                                            prevLocation = location;
-                                        }
-                                        giantLocationMap.put(giant, location);
-
-                                        LivingEntity target = husk.getTarget();
-                                        if (target != null) {
-                                            processJump(giant, prevLocation, location, target.getLocation());
-                                        }
-                                    }
-                                }
-                            } else {
-                                // no vehicle means the giant doesn't exist anymore and the husk should also not exist
-                                husk.setHealth(0);
-
-                                trackedHusks.remove(husk);
-                                logger.fine("Husk killed because Giant died at " + husk.getLocation());
-                            }
-                        } else {
-                            trackedHusks.remove(husk);
-                            logger.fine("Husk unloaded at " + husk.getLocation());
-                        }
-                    }
-                }
-            }.runTaskTimer(plugin, configuration.attackDelay, 0L);
-        }
-
-        plugin.getServer().getPluginManager().registerEvents(this, plugin);
-    }
-
-    private void processJump(Entity giant, Location prevLocation, Location location, Location targetLocation) {
-        long now = System.currentTimeMillis();
-        if (now - giantLastJump.getOrDefault(giant, 0L) < configuration.jumpDelay) {
-            return;
-        }
-
-        if (giant.isOnGround()) {
-            giantLastJump.put(giant, now);
-            if (configuration.jumpCondition == 0) {
-                if (targetLocation.subtract(location).getY() > 0) {
-                    jump(giant);
-                }
-            } else if (configuration.jumpCondition == 1) {
-                Location delta = prevLocation.subtract(location);
-                if (targetLocation.subtract(location).getY() > 0 && (delta.getX() == 0 || delta.getZ() == 0)) {
-                    jump(giant);
-                }
-            } else if (configuration.jumpCondition == 2) {
-                Location delta = prevLocation.subtract(location);
-                if (delta.getX() == 0 || delta.getZ() == 0) {
-                    jump(giant);
-                }
-
-            } // I could probably simplify that code
-        }
-    }
-
-    private void jump(Entity giant) {
-        if (configuration.jumpMode == 1) {
-            giant.setVelocity(new Vector(0, configuration.jumpHeight, 0));
-        } else if (configuration.jumpMode == 2) {
-            giant.teleport(giant.getLocation().add(0, configuration.jumpHeight, 0));
-        }
-    } // TODO those should be moved
-
-    public LivingEntity spawnGiant(Location pos) {
-        LivingEntity entity = (LivingEntity) pos.getWorld().spawnEntity(pos, EntityType.GIANT);
-
-        if (configuration.ai) {
-            // the husk basically moves the giant
-            LivingEntity passenger = (LivingEntity) pos.getWorld().spawnEntity(pos, EntityType.HUSK);
-            new PotionEffect(PotionEffectType.INVISIBILITY, Integer.MAX_VALUE, 1).apply(passenger);
-            passenger.setInvulnerable(true);
-            passenger.setPersistent(true);
-            passenger.getPersistentDataContainer().set(huskKey, PersistentDataType.INTEGER, VERSION);
-
-            entity.addPassenger(passenger);
-
-            trackedHusks.add((Husk) passenger);
-        }
-
-        configuration.effects.forEach(entity::addPotionEffect);
-        //trackedGiants.add((Giant) entity);
-
-        logger.fine("Spawned a Giant at " + pos);
-
-        return entity;
-    }
-
-    @EventHandler
-    public void onChunkLoad(ChunkLoadEvent event) {
-        Entity[] entities = event.getChunk().getEntities();
-        logger.fine("Chunk loaded: " + event.getChunk().getX() + " " + event.getChunk().getZ());
-
-        Husk[] husks = Arrays.stream(entities)
-                .filter(entity -> entity instanceof Husk && entity.getPersistentDataContainer().has(huskKey, PersistentDataType.INTEGER))
-                .map(Husk.class::cast)
-                .toArray(Husk[]::new);
-
-        for (Husk husk : husks) {
-            logger.fine("Husk found at " + husk.getLocation());
-
-            Entity giant = husk.getVehicle();
-
-            if (giant instanceof Giant) {
-                trackedHusks.add(husk);
-                //trackedGiants.add((Giant) giant);
-
-                logger.fine("Tracking a loaded Giant at " + giant.getLocation());
-            } else {
-                // kill stray husks, that is those without a giant
-                husk.setHealth(0);
-
-                logger.fine("Stray Husk killed at " + husk.getLocation());
-            }
-        }
-    }
-
-    @EventHandler
-    public void entitySpawn(EntitySpawnEvent e) {
-        if (configuration.worldBlacklist.contains(e.getLocation().getWorld().getName()))
-            return;
-
-        if (e.getEntityType() == EntityType.ZOMBIE) {
-            if (configuration.chance > random.nextDouble()) {
-                e.setCancelled(true);
-                spawnGiant(e.getLocation());
-
-                logger.fine("Spawned a Giant by chance at " + e.getLocation());
-            }
-        }
-    }
-
-    @EventHandler
-    public void entityDeath(EntityDeathEvent e) {
-        LivingEntity entity = e.getEntity();
-
-        if (entity.getType() == EntityType.GIANT) {
-            Location location = entity.getLocation();
-            logger.fine("A Giant died at " + location);
-
-            for (Drop drop : configuration.drops) {
-                logger.fine("Rolling a drop");
-
-                if (drop.chance > random.nextDouble()) {
-                    ItemStack is = drop.generateItemStack();
-                    entity.getWorld().dropItemNaturally(location, is);
-
-                    logger.fine("Dropped " + is);
-                }
-            }
-
-            for (Entity passenger : entity.getPassengers()) {
-                if (passenger.getPersistentDataContainer().has(huskKey, PersistentDataType.INTEGER)) {
-                    ((LivingEntity) passenger).setHealth(0);
-                    logger.fine("Killed a Husk");
-                }
-            }
-        }
-    }
-}

src/main/java/eu/m724/giants/GiantsCommand.java

@@ -1,5 +1,8 @@
 package eu.m724.giants;
 
+import eu.m724.giants.updater.UpdateCommand;
+import net.md_5.bungee.api.ChatColor;
+import org.bukkit.Material;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandExecutor;
 import org.bukkit.command.CommandSender;
@@ -18,118 +21,89 @@ import java.util.Map;
 
 public class GiantsCommand implements CommandExecutor {
     private final GiantsPlugin plugin;
-    private final Configuration configuration;
 
-    public GiantsCommand(GiantsPlugin plugin, Configuration configuration) {
+    private final UpdateCommand updateCommand;
+
+    public GiantsCommand(GiantsPlugin plugin, UpdateCommand updateCommand) {
         this.plugin = plugin;
-        this.configuration = configuration;
+        this.updateCommand = updateCommand;
     }
 
     @Override
     public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
         if (args.length == 0) {
-            sender.sendMessage("Giants " + plugin.getDescription().getVersion());
+            sender.sendMessage(ChatColor.GRAY + "Giants " + plugin.getDescription().getVersion());
             return true;
         }
 
         String action = args[0];
 
         if (!sender.hasPermission("giants.command." + action)) {
-            sender.sendMessage("You don't have permission to use this command, or it doesn't exist.");
+            sender.sendMessage(ChatColor.GRAY + "You don't have permission to use this command, or it doesn't exist.");
             return true;
         }
 
-        Player player = sender instanceof Player ? (Player) sender : null;
-
-        if (action.equals("spawn")) {
-            if (player != null) {
-                plugin.spawnGiant(player.getLocation());
-                sender.sendMessage("Spawned a Giant");
-            } else {
-                sender.sendMessage("Only players can use this command.");
-            }
-        } else if (action.equals("serialize")) {
-            if (player != null) {
-                ItemStack itemStack = player.getInventory().getItemInMainHand();
-
-                List<Map<String, Object>> list = new ArrayList<>();
-                Map<String, Object> map = new LinkedHashMap<>();
-                map.put("chance", 1);
-                map.put("quantityMin", itemStack.getAmount());
-                map.put("quantityMax", itemStack.getAmount());
-                map.put("itemStack", itemStack);
-                list.add(map);
-
-                YamlConfiguration yamlConfiguration = new YamlConfiguration();
-
-                try {
-                    Method method = yamlConfiguration.getClass().getMethod("setInlineComments", String.class, List.class);
-
-                    yamlConfiguration.set("v", list);
-                    method.invoke(yamlConfiguration, "v", List.of("Copy the below content to your config.yml"));
-                } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
-                    yamlConfiguration.set("v", null); // two latter exceptions happen after setting
-                    yamlConfiguration.set("copy_everything_below_to_config_yml", list);
-                }
-
-                long now = System.currentTimeMillis();
-                String name = "item-" + now + ".yml";
-                File file = new File(plugin.getDataFolder(), name);
-
-                try {
-                    yamlConfiguration.save(file);
-                    sender.sendMessage("Saved to plugins/Giants/" + name + ". To add it as a drop, see instructions in the file.");
-                } catch (IOException e) {
-                    sender.sendMessage("Error saving file. See console for details.");
-                    throw new RuntimeException("Error saving file to " + file.getName(), e);
-                }
-            } else {
-                sender.sendMessage("Only players can use this command.");
-            }
-        } else if (action.equals("jm")) { // TODO remove
-            if (args.length > 1) {
-                int mode = Integer.parseInt(args[1]);
-                configuration.jumpMode = mode;
-
-                sender.sendMessage("Jump mode set to " + mode);
-                sender.sendMessage("This command doesn't check if it's valid, an invalid value turns off jumping.");
-
-                if (configuration.jumpHeight == -1) {
-                    configuration.jumpHeight = configuration.defaultJumpHeight();
-                    sender.sendMessage("Jump height set to " + configuration.jumpHeight + ". Modify it with /giants jumpheight");
-                }
-            } else {
-                sender.sendMessage("Jump mode: " + configuration.jumpMode);
-            }
-        } else if (action.equals("jh")) {
-            if (args.length > 1) {
-                double height = Double.parseDouble(args[1]);
-                configuration.jumpHeight = height;
-
-                sender.sendMessage("Jump height set to " + height);
-            } else {
-                sender.sendMessage("Jump height: " + configuration.jumpHeight);
-            }
-        } else if (action.equals("jc")) {
-            if (args.length > 1) {
-                int condition = Integer.parseInt(args[1]);
-                configuration.jumpCondition = condition;
-
-                sender.sendMessage("Jump condition set to " + condition);
-            } else {
-                sender.sendMessage("Jump condition: " + configuration.jumpCondition);
-            }
-        } else if (action.equals("jd")) {
-            if (args.length > 1) {
-                int delay = Integer.parseInt(args[1]);
-                configuration.jumpDelay = delay;
-
-                sender.sendMessage("Jump delay set to " + delay);
-            } else {
-                sender.sendMessage("Jump delay: " + configuration.jumpDelay);
-            }
+        if (action.equals("serialize")) {
+            serializeCommand(sender);
+        } else if (action.equals("update")) {
+            if (updateCommand != null)
+                updateCommand.updateCommand(sender, args);
+            else
+                sender.sendMessage(ChatColor.GRAY + "Updater is disabled");
         }
 
         return true;
     }
+
+    private void serializeCommand(CommandSender sender) {
+        if (!(sender instanceof Player player)) {
+            sender.sendMessage("Only players can use this command.");
+            return;
+        }
+
+        ItemStack itemStack = player.getInventory().getItemInMainHand();
+
+        if (itemStack.getType() == Material.AIR) {
+            sender.sendMessage(ChatColor.RED + "You must hold an item in your main hand.");
+            return;
+        }
+
+        try {
+            String name = serializeDrop(player.getInventory().getItemInMainHand());
+            sender.sendMessage("Saved to plugins/Giants/" + name + ". Please follow the instructions in that file.");
+        } catch (IOException e) {
+            sender.sendMessage("Error saving file. See console for details.");
+            throw new RuntimeException("Error saving drop configuration file", e);
+        }
+    }
+
+    private String serializeDrop(ItemStack itemStack) throws IOException {
+        List<Map<String, Object>> list = new ArrayList<>();
+        Map<String, Object> map = new LinkedHashMap<>();
+        map.put("chance", 1);
+        map.put("quantityMin", itemStack.getAmount());
+        map.put("quantityMax", itemStack.getAmount());
+        map.put("itemStack", itemStack);
+        list.add(map);
+
+        YamlConfiguration yamlConfiguration = new YamlConfiguration();
+
+        try {
+            Method method = yamlConfiguration.getClass().getMethod("setInlineComments", String.class, List.class);
+
+            yamlConfiguration.set("v", list);
+            method.invoke(yamlConfiguration, "v", List.of("Copy the below content to your config.yml"));
+        } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
+            yamlConfiguration.set("v", null); // two latter exceptions happen after setting
+            yamlConfiguration.set("copy_everything_below_to_config_yml", list);
+        }
+
+        long now = System.currentTimeMillis();
+        String name = "item-" + now + ".yml";
+        File file = new File(plugin.getDataFolder(), name);
+
+        yamlConfiguration.save(file);
+
+        return name;
+    }
 }

src/main/java/eu/m724/giants/GiantsPlugin.java

@@ -1,19 +1,24 @@
 package eu.m724.giants;
 
+import eu.m724.giants.ai.GiantProcessor;
+import eu.m724.giants.configuration.Configuration;
+import eu.m724.giants.updater.PluginUpdater;
+import eu.m724.giants.updater.UpdateCommand;
+import eu.m724.jarupdater.verify.VerificationException;
 import org.bstats.bukkit.Metrics;
+import org.bstats.charts.SimplePie;
 import org.bukkit.Location;
 import org.bukkit.command.CommandExecutor;
-import org.bukkit.entity.Giant;
-import org.bukkit.entity.LivingEntity;
 import org.bukkit.plugin.java.JavaPlugin;
 
 import java.io.File;
-import java.lang.reflect.Constructor;
+import java.io.IOException;
+import java.io.InputStream;
 
 public class GiantsPlugin extends JavaPlugin implements CommandExecutor {
 	private final File configFile = new File(getDataFolder(), "config.yml");
 
-	private final Configuration configuration = new Configuration(this, configFile);
+	private static Configuration configuration;
 	private final GiantProcessor giantProcessor = new GiantProcessor(this, configuration);
 
 	@Override
@@ -22,32 +27,60 @@ public class GiantsPlugin extends JavaPlugin implements CommandExecutor {
 			saveResource("config.yml", false);
 		}
 
-		configuration.load();
-
-		getCommand("giants").setExecutor(new GiantsCommand(this, configuration));
+		configuration = Configuration.load(this, configFile);
 
 		giantProcessor.start();
 
-		// bStats is optional
-        try {
-			Class<?> clazz = Class.forName("eu.m724.giants.bukkit.Metrics");
-            Constructor<?> constructor = clazz.getDeclaredConstructor(JavaPlugin.class, int.class);
-			constructor.newInstance(this, 14131);
-			getLogger().info("Enabled bStats");
-        } catch (Exception e) {
-			getLogger().info("Not using bStats (" + e.getClass().getName() + ")");
+		PluginUpdater updater = null;
+		UpdateCommand updateCommand = null;
+		if (configuration.updaterEnabled()) {
+            try (InputStream keyInputStream = getResource("verifies_downloaded_jars.pem")) {
+                updater = PluginUpdater.build(this, getFile(), configuration.updaterChannel(), keyInputStream);
+            } catch (IOException e) {
+                getLogger().severe("Failed to load updater");
+				e.printStackTrace();
+            }
+
+            if (updater != null) {
+                try {
+                    updater.verifyJar(
+                            getFile().getPath().replace(".paper-remapped/", "") // paper remapping removes data from manifest
+                    );
+                } catch (VerificationException e) {
+                    getLogger().warning(e.getMessage());
+                    getLogger().warning("Plugin JAR is of invalid signature. If this persists, re-download the JAR from SpigotMC.");
+                    getLogger().warning("If on Paper, try removing plugins/.paper-remapped");
+
+                }
+                updater.initNotifier();
+				updateCommand = new UpdateCommand(updater);
+            }
+
         }
+
+		getCommand("giants").setExecutor(new GiantsCommand(this, updateCommand));
+
+		Metrics metrics = new Metrics(this, 14131);
+		metrics.addCustomChart(new SimplePie("jump_mode", () -> String.valueOf(configuration.jumpMode())));
+		metrics.addCustomChart(new SimplePie("jump_condition", () -> String.valueOf(configuration.jumpCondition())));
+		metrics.addCustomChart(new SimplePie("jump_delay", () -> String.valueOf(configuration.jumpDelay())));
+		metrics.addCustomChart(new SimplePie("jump_height", () -> String.valueOf(configuration.jumpHeight())));
     }
 
+	public static Configuration getConfiguration() {
+		return configuration;
+	}
+
 	// TODO api, untested
 
 	/**
-	 * Spawns a {@link Giant} at the specified {@link Location}
+	 * Checks if a giant can be spawned at a location<br>
+	 * The check is very approximate, but works for most scenarios
 	 *
 	 * @param location The location
-	 * @return The spawned {@link Giant} (as a {@link LivingEntity}, but you can cast)
+	 * @return Whether a giant can be spawned
 	 */
-	public LivingEntity spawnGiant(Location location) {
-		return giantProcessor.spawnGiant(location);
+	public boolean isSpawnableAt(Location location) {
+		return giantProcessor.isSpawnableAt(location);
 	}
 }

src/main/java/eu/m724/giants/ai/GiantJumper.java

@@ -0,0 +1,51 @@
+package eu.m724.giants.ai;
+
+import eu.m724.giants.GiantsPlugin;
+import eu.m724.giants.configuration.Configuration;
+import org.bukkit.Location;
+import org.bukkit.entity.Entity;
+import org.bukkit.util.Vector;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class GiantJumper {
+    private final Configuration configuration = GiantsPlugin.getConfiguration();
+
+    private final Map<Entity, Long> giantLastJump = new HashMap<>();
+
+    void processJump(Entity giant, Location prevLocation, Location location, Location targetLocation) {
+        long now = System.currentTimeMillis();
+        if (now - giantLastJump.getOrDefault(giant, 0L) < configuration.jumpDelay()) {
+            return;
+        }
+
+        if (giant.isOnGround()) {
+            giantLastJump.put(giant, now);
+            if (configuration.jumpCondition() == 0) {
+                if (targetLocation.subtract(location).getY() > 0) {
+                    jump(giant);
+                }
+            } else if (configuration.jumpCondition() == 1) {
+                Location delta = prevLocation.subtract(location);
+                if (targetLocation.subtract(location).getY() > 0 && (delta.getX() == 0 || delta.getZ() == 0)) {
+                    jump(giant);
+                }
+            } else if (configuration.jumpCondition() == 2) {
+                Location delta = prevLocation.subtract(location);
+                if (delta.getX() == 0 || delta.getZ() == 0) {
+                    jump(giant);
+                }
+
+            } // I could probably simplify that code
+        }
+    }
+
+    private void jump(Entity giant) {
+        if (configuration.jumpMode() == 1) {
+            giant.setVelocity(new Vector(0, configuration.jumpHeight(), 0));
+        } else if (configuration.jumpMode() == 2) {
+            giant.teleport(giant.getLocation().add(0, configuration.jumpHeight(), 0));
+        }
+    }
+}

src/main/java/eu/m724/giants/ai/GiantProcessor.java

@@ -0,0 +1,163 @@
+package eu.m724.giants.ai;
+
+import eu.m724.giants.Drop;
+import eu.m724.giants.configuration.Configuration;
+import org.bukkit.Location;
+import org.bukkit.NamespacedKey;
+import org.bukkit.entity.*;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.entity.EntityDeathEvent;
+import org.bukkit.event.entity.EntitySpawnEvent;
+import org.bukkit.event.world.ChunkLoadEvent;
+import org.bukkit.persistence.PersistentDataType;
+import org.bukkit.plugin.java.JavaPlugin;
+import org.bukkit.potion.PotionEffect;
+import org.bukkit.potion.PotionEffectType;
+
+import java.util.*;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+// TODO move ai stuff to another class
+/**
+ * A processor class that processes giants
+ */
+public class GiantProcessor implements Listener {
+    private static final int VERSION = 1;
+
+    private final JavaPlugin plugin;
+    final Configuration configuration;
+    private final Logger logger;
+
+    final Set<Husk> trackedHusks = new HashSet<>();
+    final Map<Entity, Location> giantLocationMap = new HashMap<>();
+
+    private final ThreadLocalRandom random = ThreadLocalRandom.current();
+    private final NamespacedKey huskKey;
+
+    public GiantProcessor(JavaPlugin plugin, Configuration configuration) {
+        this.plugin = plugin;
+        this.configuration = configuration;
+        this.logger = Logger.getLogger(plugin.getLogger().getName() + ".GiantProcessor");
+        logger.setLevel(Level.ALL);
+        this.huskKey = new NamespacedKey(plugin, "husk");
+    }
+
+    public void start() {
+        if (configuration.aiEnabled()) {
+            new GiantTicker(this).schedule(plugin);
+        }
+
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
+    }
+
+    /**
+     * The check is very approximate
+     *
+     * @param location the location
+     * @return whether a giant can be spawned here
+     */
+    public boolean isSpawnableAt(Location location) {
+        for (int y=0; y<=12; y++) {
+            if (!location.clone().add(0, y, 0).getBlock().isEmpty()) // isPassable also seems good
+                return false;
+        }
+
+        return true;
+    }
+
+    @EventHandler
+    public void onChunkLoad(ChunkLoadEvent event) {
+        Entity[] entities = event.getChunk().getEntities();
+        logger.fine("Chunk loaded: " + event.getChunk().getX() + " " + event.getChunk().getZ());
+
+        Husk[] husks = Arrays.stream(entities)
+                .filter(entity -> entity instanceof Husk && entity.getPersistentDataContainer().has(huskKey, PersistentDataType.INTEGER))
+                .map(Husk.class::cast)
+                .toArray(Husk[]::new);
+
+        for (Husk husk : husks) {
+            logger.fine("Husk found at " + husk.getLocation());
+
+            Entity giant = husk.getVehicle();
+
+            if (giant instanceof Giant) {
+                trackedHusks.add(husk);
+
+                logger.fine("Tracking a loaded Giant at " + giant.getLocation());
+            } else {
+                // kill stray husks, that is those without a giant
+                husk.setHealth(0);
+
+                logger.fine("Stray Husk killed at " + husk.getLocation());
+            }
+        }
+    }
+
+    public void applyGiantsLogic(Giant giant) {
+        if (configuration.aiEnabled()) {
+            // The husk moves the giant. That's the magic.
+            LivingEntity passenger = (LivingEntity) giant.getWorld().spawnEntity(giant.getLocation(), EntityType.HUSK);
+            new PotionEffect(PotionEffectType.INVISIBILITY, Integer.MAX_VALUE, 1).apply(passenger);
+            passenger.setInvulnerable(true);
+            passenger.setPersistent(true);
+            passenger.getPersistentDataContainer().set(huskKey, PersistentDataType.INTEGER, VERSION);
+
+            giant.addPassenger(passenger);
+
+            trackedHusks.add((Husk) passenger);
+        }
+
+        configuration.potionEffects().forEach(giant::addPotionEffect);
+    }
+
+    @EventHandler
+    public void entitySpawn(EntitySpawnEvent e) {
+        if (e.getEntityType() == EntityType.GIANT) {
+            logger.fine("Handling spawned Giant at " + e.getLocation());
+
+            var giant = (Giant) e.getEntity();
+            if (giant.hasAI()) // NoAI flag
+                applyGiantsLogic(giant);
+        }
+
+        if (configuration.worldBlacklist().contains(e.getLocation().getWorld().getName()))
+            return;
+
+        if (e.getEntityType() == EntityType.ZOMBIE) {
+            if (configuration.spawnChance() > random.nextDouble()) {
+                logger.fine("Trying to spawn a Giant by chance at " + e.getLocation());
+                if (isSpawnableAt(e.getLocation())) {
+                    logger.fine("Spawned a Giant by chance at " + e.getLocation());
+                    e.getLocation().getWorld().spawnEntity(e.getLocation(), EntityType.GIANT);
+                    e.setCancelled(true);
+                }
+            }
+        }
+    }
+
+    @EventHandler
+    public void entityDeath(EntityDeathEvent e) {
+        LivingEntity entity = e.getEntity();
+
+        if (entity.getType() == EntityType.GIANT) {
+            Location location = entity.getLocation();
+            logger.fine("A Giant died at " + location);
+
+            for (Drop drop : configuration.drops()) {
+                logger.fine("Rolling a drop: " + drop.itemStack().toString());
+
+                drop.dropAt(location);
+            }
+
+            for (Entity passenger : entity.getPassengers()) {
+                if (passenger.getPersistentDataContainer().has(huskKey, PersistentDataType.INTEGER)) {
+                    ((LivingEntity) passenger).setHealth(0);
+                    logger.fine("Killed a Husk");
+                }
+            }
+        }
+    }
+}

src/main/java/eu/m724/giants/ai/GiantTicker.java

@@ -0,0 +1,75 @@
+package eu.m724.giants.ai;
+
+import eu.m724.giants.GiantsPlugin;
+import eu.m724.giants.configuration.Configuration;
+import org.bukkit.Location;
+import org.bukkit.entity.*;
+import org.bukkit.plugin.Plugin;
+import org.bukkit.scheduler.BukkitRunnable;
+
+import java.util.Set;
+
+/**
+ * Ticks giants
+ */
+public class GiantTicker extends BukkitRunnable {
+    private final Configuration configuration = GiantsPlugin.getConfiguration();
+    private final GiantJumper jumper = new GiantJumper();
+
+    private final GiantProcessor giantProcessor;
+
+    public GiantTicker(GiantProcessor giantProcessor) {
+        this.giantProcessor = giantProcessor;
+    }
+
+    void schedule(Plugin plugin) {
+        this.runTaskTimer(plugin, 0, configuration.attackDelay());
+    }
+
+    @Override
+    public void run() {
+        for (Husk husk : Set.copyOf(giantProcessor.trackedHusks)) {
+            if (husk.isValid()) {
+                Location huskLocation = husk.getLocation();
+                Entity giant = husk.getVehicle();
+
+                if (giant instanceof Giant) {
+                    if (giant.isValid()) { // TODO reconsider
+                        giant.getWorld().getNearbyEntities(
+                                giant.getBoundingBox().expand(configuration.attackReach()),
+                                e -> (e instanceof Player && !e.isInvulnerable())
+                        ).forEach(p -> ((Player) p).damage(configuration.attackDamage(), giant));
+                        giant.setRotation(huskLocation.getYaw(), huskLocation.getPitch());
+
+                        // TODO move whole into that class?
+                        if (configuration.jumpMode() != 0) {
+                            // tracking location is only required for jumping
+                            Location prevLocation = giantProcessor.giantLocationMap.get(giant);
+                            Location location = giant.getLocation();
+                            if (prevLocation == null) {
+                                prevLocation = location;
+                            }
+                            giantProcessor.giantLocationMap.put(giant, location);
+
+                            LivingEntity target = husk.getTarget();
+                            if (target != null) {
+                                jumper.processJump(giant, prevLocation, location, target.getLocation());
+                            }
+                        }
+                    }
+                } else {
+                    // no vehicle means the giant doesn't exist anymore and the husk should also not exist
+                    husk.setHealth(0);
+
+                    giantProcessor.trackedHusks.remove(husk);
+                    //logger.fine("Husk killed because Giant died at " + husk.getLocation());
+                }
+            } else {
+                giantProcessor.trackedHusks.remove(husk);
+                //logger.fine("Husk unloaded at " + husk.getLocation());
+            }
+        }
+    }
+
+
+}

src/main/java/eu/m724/giants/configuration/Configuration.java

@@ -0,0 +1,128 @@
+package eu.m724.giants.configuration;
+
+import eu.m724.giants.Drop;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.plugin.Plugin;
+import org.bukkit.potion.PotionEffect;
+import org.bukkit.util.Vector;
+
+import java.io.File;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.logging.Logger;
+
+public record Configuration(
+        boolean updaterEnabled,
+        String updaterChannel,
+
+        boolean aiEnabled,
+
+        double attackDamage,
+        int attackDelay,
+        Vector attackReach,
+
+        int jumpMode,
+        int jumpCondition,
+        int jumpDelay,
+        double jumpHeight,
+
+        double spawnChance,
+        List<String> worldBlacklist,
+        List<PotionEffect> potionEffects,
+        List<Drop> drops
+
+) {
+    // TODO not use logger here
+    private static Logger LOGGER;
+
+    public static Configuration load(Plugin plugin, File file) {
+        LOGGER = Logger.getLogger(plugin.getLogger().getName() + ".Configuration");
+
+        YamlConfiguration config = YamlConfiguration.loadConfiguration(file);
+
+        boolean updaterEnabled = true;
+        String updaterChannel = config.getString("updater", "release");
+
+        if (updaterChannel.equalsIgnoreCase("false")) {
+            updaterEnabled = false;
+        }
+
+
+        boolean aiEnabled = config.getBoolean("ai");
+
+        double attackDamage = config.getDouble("attackDamage");
+        int attackDelay = config.getInt("attackDelay");
+        Vector attackReach = new Vector(
+                config.getDouble("attackReach"),
+                config.getDouble("attackVerticalReach"),
+                config.getDouble("attackReach")
+        );
+
+        int jumpMode = config.getInt("jumpMode");
+        int jumpCondition = config.getInt("jumpCondition");
+        int jumpDelay = config.getInt("jumpDelay");
+        double jumpHeight = config.getDouble("jumpHeight", defaultJumpHeight(jumpMode));
+
+        double spawnChance = config.getDouble("chance");
+
+        List<String> worldBlacklist = config.getStringList("blacklist");
+
+        List<PotionEffect> potionEffects = config.getStringList("effects").stream()
+                .map(Configuration::makePotionEffect)
+                .filter(Objects::nonNull)
+                .toList();
+
+        List<Drop> drops = config.getMapList("drops").stream()
+                .map(Configuration::makeDrop)
+                .filter(Objects::nonNull)
+                .toList();
+
+        return new Configuration(
+                updaterEnabled, updaterChannel, aiEnabled, attackDamage, attackDelay, attackReach, jumpMode, jumpCondition, jumpDelay, jumpHeight, spawnChance, worldBlacklist, potionEffects, drops
+        );
+    }
+
+    private static double defaultJumpHeight(int jumpMode) {
+        return switch (jumpMode) {
+            case 1, 2 -> 0.42;
+            case 3, 4 -> 1.2;
+            default -> -1;
+        };
+    }
+
+    private static Drop makeDrop(Map<?, ?> dropMap) {
+        try {
+            return ListParsers.makeDrop(dropMap);
+        } catch (ParseException e) {
+            LOGGER.warning("Failed to parse drop:");
+            LOGGER.warning("  At: " + dropMap);
+            LOGGER.warning("  " + e.getMessage());
+        }
+
+        return null;
+    }
+
+    private static PotionEffect makePotionEffect(String line) {
+        try {
+            return ListParsers.makePotionEffect(line);
+        } catch (ParseException e) {
+            LOGGER.warning("Failed to parse potion effect:");
+            LOGGER.warning("  At line: " + line);
+            LOGGER.warning("  " + e.getMessage());
+        }
+
+        return null;
+    }
+
+
+    static void assertParse(boolean assertion, String message) throws ParseException {
+        if (!assertion) throw new ParseException(message);
+    }
+
+    public static class ParseException extends Exception {
+        public ParseException(String message) {
+            super(message);
+        }
+    }
+}

src/main/java/eu/m724/giants/configuration/ListParsers.java

@@ -0,0 +1,69 @@
+package eu.m724.giants.configuration;
+
+import eu.m724.giants.Drop;
+import eu.m724.giants.configuration.Configuration.ParseException;
+import org.bukkit.Material;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.potion.PotionEffect;
+import org.bukkit.potion.PotionEffectType;
+
+import java.util.Map;
+
+import static eu.m724.giants.configuration.Configuration.assertParse;
+
+public class ListParsers {
+    public static PotionEffect makePotionEffect(String line) throws ParseException {
+        if (line == null || line.trim().isEmpty()) {
+            throw new ParseException("Cannot parse empty or null line into a PotionEffect.");
+        }
+
+        String[] parts = line.split(":", 2);
+        assertParse(parts.length == 2, "Invalid PotionEffect format (expected 'TYPE:AMPLIFIER')");
+
+        PotionEffectType effectType = PotionEffectType.getByName(parts[0].trim());
+        assertParse(effectType != null, "Unknown PotionEffectType: " + parts[0].trim());
+
+        int amplifier;
+        try {
+            amplifier = Integer.parseInt(parts[1].trim());
+        } catch (IllegalArgumentException e) {
+            throw new ParseException("Invalid amplifier format (expected integer): " + parts[1].trim());
+        }
+
+        assertParse(amplifier > 0, "Amplifier must be bigger than 0, is: " + amplifier);
+        assertParse(amplifier < 256, "Amplifier must be at most 255, is: " + amplifier);
+
+        return new PotionEffect(effectType, Integer.MAX_VALUE, amplifier);
+    }
+
+    // TODO refactor this
+    public static Drop makeDrop(Map<?, ?> dropMap) throws ParseException {
+        ItemStack itemStack;
+        if (dropMap.containsKey("itemStack")) {
+            itemStack = (ItemStack) dropMap.get("itemStack");
+        } else {
+            Material material = Material.getMaterial((String) dropMap.get("material"));
+            assertParse(material != null, "Invalid Material: " + dropMap.get("material"));
+
+            itemStack = new ItemStack(material, 1);
+        }
+
+        int min = (int) dropMap.get("quantityMin");
+        int max = (int) dropMap.get("quantityMax");
+        assertParse(min > 0, "Minimum quantity must be more than 0, is: " + min);
+        assertParse(max > 0, "Maximum quantity must be more than 0, is: " + max);
+        assertParse(min < 100, "Minimum quantity must be less than 100, is: " + min);
+        assertParse(max < 100, "Maximum quantity must be less than 100, is: " + max);
+
+        double chance = ((Number) dropMap.get("chance")).doubleValue();
+
+        if (chance > 1 && chance <= 100) {
+            chance /= 100; // user might have misunderstood
+        }
+
+        assertParse(chance > 0, "Chance must be more than 0, is: " + chance);
+        assertParse(chance <= 1, "Chance must be at most 1, is: " + chance);
+
+        return new Drop(itemStack, min, max, chance);
+    }
+}

src/main/java/eu/m724/giants/updater/PluginEnvironment.java

@@ -0,0 +1,12 @@
+package eu.m724.giants.updater;
+
+import eu.m724.jarupdater.environment.ConstantEnvironment;
+import org.bukkit.plugin.Plugin;
+
+import java.nio.file.Path;
+
+public class PluginEnvironment extends ConstantEnvironment {
+    public PluginEnvironment(Plugin plugin, String channel, Path path) {
+        super(plugin.getDescription().getVersion(), channel, path);
+    }
+}

src/main/java/eu/m724/giants/updater/PluginUpdater.java

@@ -0,0 +1,47 @@
+package eu.m724.giants.updater;
+
+import eu.m724.jarupdater.download.Downloader;
+import eu.m724.jarupdater.download.SimpleDownloader;
+import eu.m724.jarupdater.environment.Environment;
+import eu.m724.jarupdater.live.GiteaMetadataDAO;
+import eu.m724.jarupdater.live.MetadataDAO;
+import eu.m724.jarupdater.live.MetadataFacade;
+import eu.m724.jarupdater.updater.Updater;
+import eu.m724.jarupdater.verify.SignatureVerifier;
+import eu.m724.jarupdater.verify.VerificationException;
+import eu.m724.jarupdater.verify.Verifier;
+import org.bukkit.plugin.Plugin;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+
+public class PluginUpdater extends Updater {
+    private final Plugin plugin;
+    boolean updatePending = false;
+
+    private PluginUpdater(Environment environment, MetadataFacade metadataProvider, Downloader downloader, Verifier verifier, Plugin plugin) {
+        super(environment, metadataProvider, downloader, verifier);
+        this.plugin = plugin;
+    }
+
+    public static PluginUpdater build(Plugin plugin, File file, String channel, InputStream keyInputStream) throws IOException {
+        Environment environment = new PluginEnvironment(plugin, channel, file.toPath());
+        MetadataDAO metadataDAO = new GiteaMetadataDAO("https://git.m724.eu/Minecon724/giants-metadata", "master");
+        MetadataFacade metadataFacade = new MetadataFacade(environment, metadataDAO);
+        Downloader downloader = new SimpleDownloader("giants");
+        SignatureVerifier verifier = new SignatureVerifier();
+        verifier.loadPublicKey(keyInputStream);
+
+        return new PluginUpdater(environment, metadataFacade, downloader, verifier, plugin);
+    }
+
+    public void verifyJar(String jarPath) throws VerificationException {
+        verifier.verify(jarPath);
+    }
+
+    public void initNotifier() {
+        UpdateNotifier updateNotifier = new UpdateNotifier(plugin, this, (version) -> {});
+        updateNotifier.register();
+    }
+}

src/main/java/eu/m724/giants/updater/UpdateCommand.java

@@ -0,0 +1,110 @@
+package eu.m724.giants.updater;
+
+import net.md_5.bungee.api.ChatColor;
+import net.md_5.bungee.api.chat.ClickEvent;
+import net.md_5.bungee.api.chat.HoverEvent;
+import net.md_5.bungee.api.chat.TextComponent;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+import java.nio.file.NoSuchFileException;
+import java.time.LocalDate;
+import java.time.format.DateTimeFormatter;
+
+/**
+ * not actually a command but deserves a separate file
+ */
+public class UpdateCommand {
+    private final PluginUpdater updater;
+
+    public UpdateCommand(PluginUpdater updater) {
+        this.updater = updater;
+    }
+
+    private void sendChangelogMessage(CommandSender sender, String changelogUrl) {
+        if (changelogUrl != null) {
+            if (sender instanceof Player) {
+                TextComponent textComponent = new TextComponent("Click here to open changelog");
+                textComponent.setUnderlined(true);
+                textComponent.setColor(ChatColor.AQUA);
+                textComponent.setHoverEvent(new HoverEvent(HoverEvent.Action.SHOW_TEXT, TextComponent.fromLegacyText(changelogUrl)));
+                textComponent.setClickEvent(new ClickEvent(ClickEvent.Action.OPEN_URL, changelogUrl));
+                sender.spigot().sendMessage(textComponent);
+            } else {
+                sender.sendMessage("Changelog: " + changelogUrl);
+            }
+        }
+    }
+
+    public void updateCommand(CommandSender sender, String[] args) {
+        sender.sendMessage(ChatColor.GRAY + "Please wait...");
+        sender.sendMessage(ChatColor.GRAY + "Channel: " + updater.getEnvironment().getChannel());
+
+        if (updater.updatePending) {
+            sender.sendMessage(ChatColor.YELLOW + "" + ChatColor.BOLD + "(!) Server restart required");
+        }
+
+        String action = args.length > 1 ? args[1] : null; // remember this function is proxied
+
+        if (action == null) {
+            updater.getLatestVersion().thenAccept(metadata -> {
+                updater.getCurrentVersion().thenAccept(metadata2 -> {
+                    sender.sendMessage(ChatColor.GOLD + "You're on Giants " + metadata2.getLabel() + " released " + formatDate(metadata2.getTimestamp()));
+                    sendChangelogMessage(sender, metadata2.getChangelogUrl());
+                }).exceptionally(e -> {
+                    sender.sendMessage(ChatColor.RED + "Error retrieving information about current version, see console for details. " + e.getMessage());
+                    e.printStackTrace();
+                    return null;
+                });
+
+                if (metadata != null) {
+                    sender.sendMessage(ChatColor.YELLOW + "" + ChatColor.BOLD + "An update is available!");
+                    sender.sendMessage(ChatColor.GOLD + "Giants " + metadata.getLabel() + " released " + formatDate(metadata.getTimestamp()));
+                    sendChangelogMessage(sender, metadata.getChangelogUrl());
+                    sender.sendMessage(ChatColor.GOLD + "To download: /giants update download");
+                } else {
+                    sender.sendMessage(ChatColor.GRAY + "No new updates");
+                }
+            }).exceptionally(e -> {
+                sender.sendMessage(ChatColor.RED + "Error checking for update. See console for details.");
+                e.printStackTrace();
+                return null;
+            });
+        } else {
+            if (!sender.hasPermission("giants.update." + action)) {
+                sender.sendMessage(ChatColor.GRAY + "You don't have permission to use this command, or it doesn't exist.");
+                return;
+            }
+
+            if (action.equals("download")) {
+                sender.sendMessage(ChatColor.GRAY + "Started download");
+
+                updater.downloadLatestVersion().thenAccept(file -> {
+                    sender.sendMessage(ChatColor.GREEN + "Download finished, install with /giants update install"); // TODO make this clickable
+                }).exceptionally(e -> {
+                    sender.sendMessage(ChatColor.RED + "Download failed. See console for details.");
+                    e.printStackTrace();
+                    return null;
+                });
+            } else if (action.equals("install")) {
+                try {
+                    updater.installLatestVersion().thenAccept(v -> {
+                        sender.sendMessage(ChatColor.GREEN + "Installation completed, restart server to apply.");
+                        updater.updatePending = true;
+                    }).exceptionally(e -> {
+                        sender.sendMessage(ChatColor.RED + "Install failed, see console for details. " + e.getMessage());
+                        e.printStackTrace();
+                        return null;
+                    });
+                } catch (NoSuchFileException e) {
+                    sender.sendMessage(ChatColor.YELLOW + "Download the update first: /giants update download");
+                }
+            }
+        }
+    }
+
+    private String formatDate(long timestamp) {
+        return LocalDate.ofEpochDay(timestamp / 86400).format(DateTimeFormatter.ofPattern("dd.MM.yyyy"));
+    }
+
+}

src/main/java/eu/m724/giants/updater/UpdateNotifier.java

@@ -0,0 +1,60 @@
+package eu.m724.giants.updater;
+
+import eu.m724.jarupdater.object.Version;
+import eu.m724.jarupdater.updater.Updater;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.bukkit.plugin.Plugin;
+import org.bukkit.scheduler.BukkitRunnable;
+
+import java.util.concurrent.CompletionException;
+import java.util.function.Consumer;
+
+public class UpdateNotifier extends BukkitRunnable implements Listener { // TODO move this to jarupdater
+    private final Updater updater;
+    private final Consumer<Version> updateConsumer;
+
+    private final Plugin plugin;
+    private Version latestVersion;
+
+    public UpdateNotifier(Plugin plugin, Updater updater, Consumer<Version> updateConsumer) {
+        this.plugin = plugin;
+        this.updater = updater;
+        this.updateConsumer = updateConsumer;
+    }
+
+    public void register() {
+        this.runTaskTimerAsynchronously(plugin, 0, 432000); // 6h
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
+    }
+
+    @Override
+    public void run() {
+        try {
+            latestVersion = updater.getLatestVersion().join();
+        } catch (CompletionException e) {
+            plugin.getLogger().info("Error trying to contact update server: " + e.getCause().getMessage());
+        }
+
+        if (latestVersion == null) return;
+        plugin.getLogger().info("Giants are outdated. /giants update");
+
+        for (Player player : plugin.getServer().getOnlinePlayers()) {
+            if (player.hasPermission("giants.update.notify")) {
+                player.sendMessage("Giants are outdated. /giants update");
+            }
+        }
+
+        updateConsumer.accept(latestVersion);
+    }
+
+    @EventHandler
+    public void onPlayerJoin(PlayerJoinEvent e) {
+        Player player = e.getPlayer();
+        if (latestVersion != null && player.hasPermission("giants.update.notify")) {
+            player.sendMessage("Giants are outdated. /giants update");
+        }
+    }
+}

src/main/resources/config.yml

@@ -1,9 +1,29 @@
 # Notes:
-# To have no values in a list, remove every value below it and change to [] like `effects: []`
+# To clear a list, remove every value below it and change to [] like `effects: []`
+
+# Enable updater
+# It still requires an admin to confirm update
+updater: true
+
+###
 
 # If disabled, the giant will not move or attack
 ai: true
 
+# In hearts, 0.5 is half a heart
+attackDamage: 1.0
+
+# Attack delay / speed, in ticks
+# 20 is 1 second
+attackDelay: 20
+
+# Self-explanatory, 0 will attack only colliding (touching) entities
+# There's no wall check yet, so it will hit through walls
+attackReach: 2
+
+# Vertical reach
+attackVerticalReach: 1
+
 # Makes giants jump. Very experimental.
 # I prefer velocity mode
 # 0 - disabled
@@ -21,20 +41,6 @@ jumpDelay: 200
 # -1: auto
 jumpHeight: -1
 
-# In hearts, 0.5 is half a heart
-attackDamage: 1.0
-
-# Attack delay / speed, in ticks
-# 20 is 1 second
-attackDelay: 20
-
-# Self-explanatory, 0 will attack only colliding (touching) entities
-# There's no wall check yet, so it will hit through walls
-attackReach: 2
-
-# Vertical reach
-attackVerticalReach: 1
-
 ###
 
 # Chance of a zombie becoming a giant. This is per each zombie spawn, natural or not.

src/main/resources/plugin.yml

@@ -9,10 +9,18 @@ load: STARTUP
 commands:
   giants:
     description: Utility command for Giants
+
 permissions:
-  giants.command.spawn:
-    description: Permits /giants spawn
-    default: op
   giants.command.serialize:
     description: Permits /giants serialize
-    default: op
+    default: op
+  giants.command.update:
+    description: Permits /giants update. Doesn't permit installing update, giants.update for that
+    default: op
+
+  giants.update.download:
+    description: Permits DOWNLOADING the latest update of the Giants plugin.
+    default: op
+  giants.update.install:
+    description: Permits INSTALLING the latest update of the Giants plugin.
+    default: op

src/main/resources/verifies_downloaded_jars.pem

@@ -0,0 +1,9 @@
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxjjjayrwlo3cnv+rX1EX
+lJN9vHS9MNfvE7zFOHr2JEAx2fRosb2oRzNK0ssoHJFOgrwLWIqrLVS8bTHRujsF
+asck2Z1RY5UGe34vNQ5u5MZvm4G25LggC6+ei2kEptoAfgp9kjmeKVPiSnruLn7N
+YQc9U4nmr/vJg+SNmy00EkXFU5z3ZsLf8aCjx9rtogZzyZmVPXEDGY3ZjzZxOpv9
+TAvSQlmrc6qmLlY7XZmJMtbzCTq+qqemZBKp6WpNmEogpPgXamOrET434+oE7OCz
++WCFKsVN8qbrQdFLf1HSjghvDoIjHcGfz6cP4nBonSKIfMcr+NziAVmimfqOiDxa
+nwIDAQAB
+-----END PUBLIC KEY-----