Add API to control scaled health. Adds BUKKIT-4590

This commit implements the ability to set the scale of hearts that the
client renders.  When the Packet44UpdateAttributes packet is sent, the
max health attribute is replaced with a scaled version, to preserve the
scaled health illusion clientside.

In order to accurately display the scaled health for players, a true
health is stored within CraftPlayer, and the datawatcher now stores the
scaled health. The getHealth() method for players still returns their
true health.

Changed setHealth() within EntityLiving to appropriately handle health
for instances of EntityPlayer. Inlined a call to
setHealth(getMaxHealth()) within the EntityLiving constructor to work
around CraftEntity instantiation.

Additionally fixes the health values sent when eating food within
FoodMetaData and ItemFood, which previously sent the unscaled health;
this commit alters them to send the properly scaled health.

Additionally fixes BUKKIT-4535, BUKKIT-4536, and BUKKIT-4127

7 files changed, 106 insertions, 11 deletions

diff --git a/src/main/java/net/minecraft/server/EntityLiving.java b/src/main/java/net/minecraft/server/EntityLiving.java
index 45b1410e..c7012c51 100644
--- a/src/main/java/net/minecraft/server/EntityLiving.java
+++ b/src/main/java/net/minecraft/server/EntityLiving.java
@@ -82,7 +82,8 @@ public abstract class EntityLiving extends Entity {
     public EntityLiving(World world) {
         super(world);
         this.ay();
-        this.setHealth(this.getMaxHealth());
+        // CraftBukkit - setHealth(getMaxHealth()) -> current  - inlined to skip the instanceof check for EntityPlayers
+        this.datawatcher.watch(6, (float) this.getAttributeInstance(GenericAttributes.a).getValue());
         this.m = true;
         this.aM = (float) (Math.random() + 1.0D) * 0.01F;
         this.setPosition(this.locX, this.locY, this.locZ);
@@ -583,10 +584,31 @@ public abstract class EntityLiving extends Entity {
     }
 
     public final float getHealth() {
+        // CraftBukkit start - Scaled Health
+        if (this instanceof EntityPlayer) {
+            return (float) ((EntityPlayer) this).getBukkitEntity().getHealth();
+        }
+        // CraftBukkit end
         return this.datawatcher.getFloat(6);
     }
 
     public void setHealth(float f) {
+        // CraftBukkit start - Scaled Health
+        if (this instanceof EntityPlayer) {
+            org.bukkit.craftbukkit.entity.CraftPlayer player = ((EntityPlayer) this).getBukkitEntity();
+            // Squeeze
+            if (f < 0.0F) {
+                player.setRealHealth(0.0D);
+            } else if (f > player.getMaxHealth()) {
+                player.setRealHealth(player.getMaxHealth());
+            } else {
+                player.setRealHealth(f);
+            }
+
+            this.datawatcher.watch(6, Float.valueOf(player.getScaledHealth()));
+            return;
+        }
+        // CraftBukkit end
         this.datawatcher.watch(6, Float.valueOf(MathHelper.a(f, 0.0F, this.getMaxHealth())));
     }
 
diff --git a/src/main/java/net/minecraft/server/EntityPlayer.java b/src/main/java/net/minecraft/server/EntityPlayer.java
index 955b75c3..58e52179 100644
--- a/src/main/java/net/minecraft/server/EntityPlayer.java
+++ b/src/main/java/net/minecraft/server/EntityPlayer.java
@@ -51,6 +51,7 @@ public class EntityPlayer extends EntityHuman implements ICrafting {
     public int newLevel = 0;
     public int newTotalExp = 0;
     public boolean keepLevel = false;
+    public double maxHealthCache;
     // CraftBukkit end
 
     public EntityPlayer(MinecraftServer minecraftserver, World world, String s, PlayerInteractManager playerinteractmanager) {
@@ -84,6 +85,7 @@ public class EntityPlayer extends EntityHuman implements ICrafting {
         this.displayName = this.name;
         this.listName = this.name;
         // this.canPickUpLoot = true; TODO
+        this.maxHealthCache = this.getMaxHealth();
         // CraftBukkit end
     }
 
@@ -234,7 +236,7 @@ public class EntityPlayer extends EntityHuman implements ICrafting {
 
             if (this.getHealth() != this.bP || this.bQ != this.foodData.a() || this.foodData.e() == 0.0F != this.bR) {
                 // CraftBukkit - Optionally scale health
-                this.playerConnection.sendPacket(new Packet8UpdateHealth(getBukkitEntity().getScaledHealth(), this.foodData.a(), this.foodData.e()));
+                this.playerConnection.sendPacket(new Packet8UpdateHealth(this.getBukkitEntity().getScaledHealth(), this.foodData.a(), this.foodData.e()));
                 this.bP = this.getHealth();
                 this.bQ = this.foodData.a();
                 this.bR = this.foodData.e() == 0.0F;
@@ -246,6 +248,12 @@ public class EntityPlayer extends EntityHuman implements ICrafting {
                 this.world.getServer().getScoreboardManager().updateAllScoresForList(IScoreboardCriteria.f, this.getLocalizedName(), com.google.common.collect.ImmutableList.of(this));
             }
 
+            // CraftBukkit start - Force max health updates
+            if (this.maxHealthCache != this.getMaxHealth()) {
+                this.getBukkitEntity().updateScaledHealth();
+            }
+            // CraftBukkit end
+
             if (this.expTotal != this.lastSentExp) {
                 this.lastSentExp = this.expTotal;
                 this.playerConnection.sendPacket(new Packet43SetExperience(this.exp, this.expTotal, this.expLevel));
diff --git a/src/main/java/net/minecraft/server/EntityTrackerEntry.java b/src/main/java/net/minecraft/server/EntityTrackerEntry.java
index 673c2042..e05296c7 100644
--- a/src/main/java/net/minecraft/server/EntityTrackerEntry.java
+++ b/src/main/java/net/minecraft/server/EntityTrackerEntry.java
@@ -250,6 +250,11 @@ public class EntityTrackerEntry {
             Set set = attributemapserver.b();
 
             if (!set.isEmpty()) {
+                // CraftBukkit start - Send scaled max health
+                if (this.tracker instanceof EntityPlayer) {
+                    ((EntityPlayer) this.tracker).getBukkitEntity().injectScaledMaxHealth(set, false);
+                }
+                // CraftBukkit end
                 this.broadcastIncludingSelf(new Packet44UpdateAttributes(this.tracker.id, set));
             }
 
@@ -321,6 +326,11 @@ public class EntityTrackerEntry {
                         AttributeMapServer attributemapserver = (AttributeMapServer) ((EntityLiving) this.tracker).aW();
                         Collection collection = attributemapserver.c();
 
+                        // CraftBukkit start - If sending own attributes send scaled health instead of current maximum health
+                        if (this.tracker.id == entityplayer.id) {
+                            ((EntityPlayer) this.tracker).getBukkitEntity().injectScaledMaxHealth(collection, false);
+                        }
+                        // CraftBukkit end
                         if (!collection.isEmpty()) {
                             entityplayer.playerConnection.sendPacket(new Packet44UpdateAttributes(this.tracker.id, collection));
                         }
diff --git a/src/main/java/net/minecraft/server/FoodMetaData.java b/src/main/java/net/minecraft/server/FoodMetaData.java
index 6e5bf831..37349f5c 100644
--- a/src/main/java/net/minecraft/server/FoodMetaData.java
+++ b/src/main/java/net/minecraft/server/FoodMetaData.java
@@ -39,7 +39,7 @@ public class FoodMetaData {
                     this.foodLevel = event.getFoodLevel();
                 }
 
-                ((EntityPlayer) entityhuman).playerConnection.sendPacket(new Packet8UpdateHealth(entityhuman.getHealth(), this.foodLevel, this.saturationLevel));
+                ((EntityPlayer) entityhuman).playerConnection.sendPacket(new Packet8UpdateHealth(((EntityPlayer) entityhuman).getBukkitEntity().getScaledHealth(), this.foodLevel, this.saturationLevel));
                 // CraftBukkit end
             }
         }
diff --git a/src/main/java/net/minecraft/server/ItemFood.java b/src/main/java/net/minecraft/server/ItemFood.java
index c0274094..78bbb59b 100644
--- a/src/main/java/net/minecraft/server/ItemFood.java
+++ b/src/main/java/net/minecraft/server/ItemFood.java
@@ -36,7 +36,7 @@ public class ItemFood extends Item {
             entityhuman.getFoodData().eat(event.getFoodLevel() - oldFoodLevel, this.getSaturationModifier());
         }
 
-        ((EntityPlayer) entityhuman).playerConnection.sendPacket(new Packet8UpdateHealth(entityhuman.getHealth(), entityhuman.getFoodData().foodLevel, entityhuman.getFoodData().saturationLevel));
+        ((EntityPlayer) entityhuman).playerConnection.sendPacket(new Packet8UpdateHealth(((EntityPlayer) entityhuman).getBukkitEntity().getScaledHealth(), entityhuman.getFoodData().foodLevel, entityhuman.getFoodData().saturationLevel));
         // CraftBukkit end
 
         world.makeSound(entityhuman, "random.burp", 0.5F, world.random.nextFloat() * 0.1F + 0.9F);
diff --git a/src/main/java/net/minecraft/server/PlayerList.java b/src/main/java/net/minecraft/server/PlayerList.java
index f24ba954..0f17c90c 100644
--- a/src/main/java/net/minecraft/server/PlayerList.java
+++ b/src/main/java/net/minecraft/server/PlayerList.java
@@ -981,7 +981,7 @@ public abstract class PlayerList {
 
     public void updateClient(EntityPlayer entityplayer) {
         entityplayer.updateInventory(entityplayer.defaultContainer);
-        entityplayer.triggerHealthUpdate();
+        entityplayer.getBukkitEntity().updateScaledHealth(); // CraftBukkit - Update scaled health on respawn and worldchange
         entityplayer.playerConnection.sendPacket(new Packet16BlockItemSwitch(entityplayer.inventory.itemInHandIndex));
     }
 
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index 977adff6..fd738566 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -7,6 +7,7 @@ import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -61,7 +62,9 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
     private final Set<String> channels = new HashSet<String>();
     private final Map<String, Player> hiddenPlayers = new MapMaker().softValues().makeMap();
     private int hash = 0;
-    private boolean scaledHealth;
+    private double health = 20;
+    private boolean scaledHealth = false;
+    private double healthScale = 20;
 
     public CraftPlayer(CraftServer server, EntityPlayer entity) {
         super(server, entity);
@@ -973,6 +976,7 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
     @Override
     public void setMaxHealth(double amount) {
         super.setMaxHealth(amount);
+        this.health = Math.min(this.health, health);
         getHandle().triggerHealthUpdate();
     }
 
@@ -999,15 +1003,66 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
         this.server.getScoreboardManager().setPlayerBoard(this, scoreboard);
     }
 
+    public void setHealthScale(double value) {
+        Validate.isTrue((float) value > 0F, "Must be greater than 0");
+        healthScale = value;
+        scaledHealth = true;
+        updateScaledHealth();
+    }
+
+    public double getHealthScale() {
+        return healthScale;
+    }
+
+    public void setHealthScaled(boolean scale) {
+        if (scaledHealth != (scaledHealth = scale)) {
+            updateScaledHealth();
+        }
+    }
+
+    public boolean isHealthScaled() {
+        return scaledHealth;
+    }
+
     public float getScaledHealth() {
-        return (float) (this.scaledHealth ? getHealth() / getMaxHealth() * 20.0D : getHealth());
+        return (float) (isHealthScaled() ? getHealth() * getHealthScale() / getMaxHealth() : getHealth());
     }
 
-    public void setScaleHealth(boolean scale) {
-        this.scaledHealth = scale;
+    @Override
+    public double getHealth() {
+        return health;
     }
 
-    public boolean isScaledHealth() {
-        return this.scaledHealth;
+    public void setRealHealth(double health) {
+        this.health = health;
+    }
+
+    public void updateScaledHealth() {
+        AttributeMapServer attributemapserver = (AttributeMapServer) getHandle().aW();
+        Set set = attributemapserver.b();
+
+        injectScaledMaxHealth(set, true);
+
+        getHandle().getDataWatcher().watch(6, (float) getScaledHealth());
+        getHandle().playerConnection.sendPacket(new Packet8UpdateHealth(getScaledHealth(), getHandle().getFoodData().a(), getHandle().getFoodData().e()));
+        getHandle().playerConnection.sendPacket(new Packet44UpdateAttributes(getHandle().id, set));
+
+        set.clear();
+        getHandle().maxHealthCache = getMaxHealth();
+    }
+
+    public void injectScaledMaxHealth(Collection collection, boolean force) {
+        if (!scaledHealth && !force) {
+            return;
+        }
+        for (Object genericInstance : collection) {
+            IAttribute attribute = ((AttributeInstance) genericInstance).a();
+            if (attribute.a().equals("generic.maxHealth")) {
+                collection.remove(genericInstance);
+                break;
+            }
+            continue;
+        }
+        collection.add(new AttributeModifiable(getHandle().aW(), (new AttributeRanged("generic.maxHealth", scaledHealth ? healthScale : getMaxHealth(), 0.0D, Float.MAX_VALUE)).a("Max Health").a(true)));
     }
 }