SakuraMC/patches/server/0063-Legacy-player-combat-mechanics.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Samsuik <kfian294ma4@gmail.com>
Date: Fri, 23 Feb 2024 01:48:08 +0000
Subject: [PATCH] Legacy player combat mechanics


diff --git a/src/main/java/me/samsuik/sakura/player/combat/CombatUtil.java b/src/main/java/me/samsuik/sakura/player/combat/CombatUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..e0aa768656081fac2c87ff573b61584dc4c1a9a3
--- /dev/null
+++ b/src/main/java/me/samsuik/sakura/player/combat/CombatUtil.java
@@ -0,0 +1,64 @@
+package me.samsuik.sakura.player.combat;
+
+import net.minecraft.core.Holder;
+import net.minecraft.core.HolderLookup;
+import net.minecraft.core.RegistryAccess;
+import net.minecraft.core.component.DataComponents;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.resources.ResourceKey;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.world.damagesource.DamageSource;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.LivingEntity;
+import net.minecraft.world.entity.ai.attributes.AttributeModifier;
+import net.minecraft.world.entity.ai.attributes.Attributes;
+import net.minecraft.world.item.*;
+import net.minecraft.world.item.component.ItemAttributeModifiers;
+import net.minecraft.world.item.enchantment.Enchantment;
+import net.minecraft.world.item.enchantment.Enchantments;
+import net.minecraft.world.item.enchantment.ItemEnchantments;
+import org.apache.commons.lang3.mutable.MutableFloat;
+
+import java.util.OptionalDouble;
+
+public final class CombatUtil {
+    public static double getLegacyAttackDifference(ItemStack itemstack) {
+        ItemAttributeModifiers defaultModifiers = itemstack.getItem().components().get(DataComponents.ATTRIBUTE_MODIFIERS);
+        if (defaultModifiers != null && !defaultModifiers.modifiers().isEmpty()) { // exists
+            double baseAttack = 0.0;
+            for (ItemAttributeModifiers.Entry entry : defaultModifiers.modifiers()) {
+                if (!entry.slot().test(EquipmentSlot.MAINHAND) || !entry.attribute().is(Attributes.ATTACK_DAMAGE))
+                    continue;
+                if (entry.modifier().operation() != AttributeModifier.Operation.ADD_VALUE)
+                    return 0;
+                baseAttack += entry.modifier().amount();
+            }
+
+            OptionalDouble legacyAttack = LegacyDamageMapping.itemAttackDamage(itemstack.getItem());
+            if (baseAttack != 0.0 && legacyAttack.isPresent()) {
+                return legacyAttack.getAsDouble() - baseAttack;
+            }
+        }
+        return 0;
+    }
+
+    public static float calculateLegacySharpnessDamage(LivingEntity entity, ItemStack itemstack, DamageSource damageSource) {
+        Holder<Enchantment> enchantment = getEnchantmentHolder(Enchantments.SHARPNESS);
+        ItemEnchantments itemEnchantments = itemstack.getEnchantments();
+        int enchantmentLevel = itemEnchantments.getLevel(enchantment);
+        MutableFloat damage = new MutableFloat();
+
+        if (entity.level() instanceof ServerLevel level) {
+            enchantment.value().modifyDamage(level, enchantmentLevel, itemstack, entity, damageSource, damage);
+        }
+        // legacy - modern
+        return enchantmentLevel * 1.25F - damage.getValue();
+    }
+
+    private static Holder<Enchantment> getEnchantmentHolder(ResourceKey<Enchantment> enchantmentKey) {
+        RegistryAccess registryAccess = MinecraftServer.getServer().registryAccess();
+        HolderLookup.RegistryLookup<Enchantment> enchantments = registryAccess.lookupOrThrow(Registries.ENCHANTMENT);
+        return enchantments.getOrThrow(enchantmentKey);
+    }
+}
diff --git a/src/main/java/me/samsuik/sakura/player/combat/LegacyDamageMapping.java b/src/main/java/me/samsuik/sakura/player/combat/LegacyDamageMapping.java
new file mode 100644
index 0000000000000000000000000000000000000000..b4ab8f172d713204bb9c1ebf575dcc28bd7dd73e
--- /dev/null
+++ b/src/main/java/me/samsuik/sakura/player/combat/LegacyDamageMapping.java
@@ -0,0 +1,64 @@
+package me.samsuik.sakura.player.combat;
+
+import it.unimi.dsi.fastutil.objects.Reference2DoubleMap;
+import it.unimi.dsi.fastutil.objects.Reference2DoubleOpenHashMap;
+import net.minecraft.core.component.DataComponents;
+import net.minecraft.core.registries.BuiltInRegistries;
+import net.minecraft.world.entity.ai.attributes.Attributes;
+import net.minecraft.world.item.*;
+import net.minecraft.world.item.component.ItemAttributeModifiers;
+
+import java.util.OptionalDouble;
+
+public final class LegacyDamageMapping {
+    private static final Reference2DoubleMap<Item> LEGACY_ITEM_DAMAGE_MAP = new Reference2DoubleOpenHashMap<>();
+
+    public static OptionalDouble itemAttackDamage(Item item) {
+        double result = LEGACY_ITEM_DAMAGE_MAP.getDouble(item);
+        return result == Double.MIN_VALUE ? OptionalDouble.empty() : OptionalDouble.of(result);
+    }
+
+    private static double adjustDamageForItem(Item item, double attackDamage) {
+        return switch (item) {
+            case SwordItem i -> 1.0;
+            case PickaxeItem i -> 1.0;
+            case ShovelItem i -> -0.5;
+            case HoeItem i -> -attackDamage;
+            case null, default -> 0.0;
+        };
+    }
+
+    static {
+        LEGACY_ITEM_DAMAGE_MAP.defaultReturnValue(Double.MIN_VALUE);
+
+        // tool material is no longer exposed
+        LEGACY_ITEM_DAMAGE_MAP.put(Items.WOODEN_AXE, 3.0);
+        LEGACY_ITEM_DAMAGE_MAP.put(Items.GOLDEN_AXE, 3.0);
+        LEGACY_ITEM_DAMAGE_MAP.put(Items.STONE_AXE, 4.0);
+        LEGACY_ITEM_DAMAGE_MAP.put(Items.IRON_AXE, 5.0);
+        LEGACY_ITEM_DAMAGE_MAP.put(Items.DIAMOND_AXE, 6.0);
+        LEGACY_ITEM_DAMAGE_MAP.put(Items.NETHERITE_AXE, 7.0);
+
+        for (Item item : BuiltInRegistries.ITEM) {
+            ItemAttributeModifiers modifiers = item.components().get(DataComponents.ATTRIBUTE_MODIFIERS);
+
+            if (modifiers == null || LEGACY_ITEM_DAMAGE_MAP.containsKey(item)) {
+                continue;
+            }
+
+            assert item instanceof AxeItem : "missing axe mapping";
+
+            double attackDamage = modifiers.modifiers().stream()
+                .filter(e -> e.attribute().is(Attributes.ATTACK_DAMAGE))
+                .mapToDouble(e -> e.modifier().amount())
+                .sum();
+
+            if (attackDamage > 0.0) {
+                double adjustment = adjustDamageForItem(item, attackDamage);
+                LEGACY_ITEM_DAMAGE_MAP.put(item, attackDamage + adjustment);
+            }
+        }
+    }
+
+    private LegacyDamageMapping() {}
+}
diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index c477eb3ea41e7d7caa04179248f116f617317cbd..3534821c8b600b9b3d3655c071fc59a3e3b4c23e 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -310,6 +310,43 @@ public abstract class LivingEntity extends Entity implements Attackable {
         ++this.noActionTime; // Above all the floats
     }
     // Spigot end
+    // Sakura start - legacy combat mechanics
+    private static final ResourceLocation LEGACY_COMBAT_MODIFIER_ID = ResourceLocation.fromNamespaceAndPath("sakura", "legacy_combat");
+    private static final AttributeModifier LEGACY_ATTACK_SPEED_MODIFIER = new AttributeModifier(LEGACY_COMBAT_MODIFIER_ID, 100.0, AttributeModifier.Operation.ADD_VALUE);
+
+    private void updateAttackSpeedModifier() {
+        AttributeInstance attackSpeed = this.getAttribute(Attributes.ATTACK_SPEED);
+        if (attackSpeed != null) {
+            attackSpeed.removeModifier(LEGACY_ATTACK_SPEED_MODIFIER);
+
+            if (this.level().sakuraConfig().players.combat.legacyCombatMechanics) {
+                attackSpeed.addTransientModifier(LEGACY_ATTACK_SPEED_MODIFIER);
+            }
+        }
+    }
+
+    protected final float getAttackDamageFromAttributes() {
+        AttributeInstance attackDamage = this.getAttribute(Attributes.ATTACK_DAMAGE);
+        AttributeModifier legacyModifier = null;
+
+        if (this.level().sakuraConfig().players.combat.legacyCombatMechanics) {
+            ItemStack heldItem = this.getLastHandItem(EquipmentSlot.MAINHAND);
+            double attackDifference = me.samsuik.sakura.player.combat.CombatUtil.getLegacyAttackDifference(heldItem);
+            legacyModifier = new AttributeModifier(LEGACY_COMBAT_MODIFIER_ID, attackDifference, AttributeModifier.Operation.ADD_VALUE);
+        }
+
+        final double damage;
+        if (attackDamage == null || legacyModifier == null) {
+            damage = this.getAttributeValue(Attributes.ATTACK_DAMAGE);
+        } else {
+            attackDamage.addTransientModifier(legacyModifier);
+            damage = this.getAttributeValue(Attributes.ATTACK_DAMAGE);
+            attackDamage.removeModifier(legacyModifier);
+        }
+
+        return (float) damage;
+    }
+    // Sakura end - legacy combat mechanics
 
     protected LivingEntity(EntityType<? extends LivingEntity> type, Level world) {
         super(type, world);
@@ -2285,7 +2322,16 @@ public abstract class LivingEntity extends Entity implements Attackable {
     protected float getDamageAfterArmorAbsorb(DamageSource source, float amount) {
         if (!source.is(DamageTypeTags.BYPASSES_ARMOR)) {
             // this.hurtArmor(damagesource, f); // CraftBukkit - actuallyHurt(DamageSource, float, EntityDamageEvent) for handle damage
+            // Sakura start - legacy combat mechanics
+            if (!this.level().sakuraConfig().players.combat.legacyCombatMechanics) {
             amount = CombatRules.getDamageAfterAbsorb(this, amount, source, (float) this.getArmorValue(), (float) this.getAttributeValue(Attributes.ARMOR_TOUGHNESS));
+            } else {
+                // See: applyArmorModifier(DamageSource, float)
+                int i = 25 - this.getArmorValue();
+                float f1 = amount * (float) i;
+                amount = f1 / 25.0F;
+            }
+            // Sakura end - legacy combat mechanics
         }
 
         return amount;
@@ -3458,6 +3504,11 @@ public abstract class LivingEntity extends Entity implements Attackable {
 
                         EnchantmentHelper.runLocationChangedEffects(worldserver, itemstack, this, enumitemslot1);
                     }
+                    // Sakura start - legacy combat mechanics
+                    if (this instanceof ServerPlayer && enumitemslot1 == EquipmentSlot.MAINHAND) {
+                        this.updateAttackSpeedModifier();
+                    }
+                    // Sakura end - legacy combat mechanics
                 }
             }
         }
diff --git a/src/main/java/net/minecraft/world/entity/player/Player.java b/src/main/java/net/minecraft/world/entity/player/Player.java
index 16f6834b88bf0b2f2157e25240e6bc51db501dce..8c8cf4b640439ca10bc030fa3194f3ff61d10e6b 100644
--- a/src/main/java/net/minecraft/world/entity/player/Player.java
+++ b/src/main/java/net/minecraft/world/entity/player/Player.java
@@ -1240,14 +1240,20 @@ public abstract class Player extends LivingEntity {
         if (playerAttackEntityEvent.callEvent() && willAttack) { // Logic moved to willAttack local variable.
             {
         // Paper end - PlayerAttackEntityEvent
-                float f = this.isAutoSpinAttack() ? this.autoSpinAttackDmg : (float) this.getAttributeValue(Attributes.ATTACK_DAMAGE);
+                float f = this.isAutoSpinAttack() ? this.autoSpinAttackDmg : this.getAttackDamageFromAttributes(); // Sakura - legacy combat mechanics
                 ItemStack itemstack = this.getWeaponItem();
                 DamageSource damagesource = (DamageSource) Optional.ofNullable(itemstack.getItem().getDamageSource(this)).orElse(this.damageSources().playerAttack(this));
                 float f1 = this.getEnchantedDamage(target, f, damagesource) - f;
                 float f2 = this.getAttackStrengthScale(0.5F);
 
+                // Sakura start - legacy combat mechanics
+                if (!this.level().sakuraConfig().players.combat.legacyCombatMechanics) {
                 f *= 0.2F + f2 * f2 * 0.8F;
                 f1 *= f2;
+                } else if (f1 != 0.0) {
+                    f1 += me.samsuik.sakura.player.combat.CombatUtil.calculateLegacySharpnessDamage(this, itemstack, damagesource);
+                }
+                // Sakura end - legacy combat mechanics
                 // this.resetAttackStrengthTicker(); // CraftBukkit - Moved to EntityLiving to reset the cooldown after the damage is dealt
                 if (target.getType().is(EntityTypeTags.REDIRECTABLE_PROJECTILE) && target instanceof Projectile) {
                     Projectile iprojectile = (Projectile) target;
@@ -1275,7 +1281,7 @@ public abstract class Player extends LivingEntity {
                     }
 
                     f += itemstack.getItem().getAttackDamageBonus(target, f, damagesource);
-                    boolean flag2 = flag && this.fallDistance > 0.0F && !this.onGround() && !this.onClimbable() && !this.isInWater() && !this.hasEffect(MobEffects.BLINDNESS) && !this.isPassenger() && target instanceof LivingEntity && !this.isSprinting();
+                    boolean flag2 = flag && this.fallDistance > 0.0F && !this.onGround() && !this.onClimbable() && !this.isInWater() && !this.hasEffect(MobEffects.BLINDNESS) && !this.isPassenger() && target instanceof LivingEntity && (this.level().sakuraConfig().players.combat.legacyCombatMechanics || !this.isSprinting()); // Sakura - legacy combat mechanics
 
                     flag2 = flag2 && !this.level().paperConfig().entities.behavior.disablePlayerCrits; // Paper - Toggleable player crits
                     if (flag2) {