SakuraMC/patches/server/0072-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/utils/CombatUtil.java b/src/main/java/me/samsuik/sakura/utils/CombatUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..b1c55ef758f61914e6df9b2c8096bce639b26353
--- /dev/null
+++ b/src/main/java/me/samsuik/sakura/utils/CombatUtil.java
@@ -0,0 +1,39 @@
+package me.samsuik.sakura.utils;
+
+import it.unimi.dsi.fastutil.objects.*;
+import net.minecraft.core.registries.BuiltInRegistries;
+import net.minecraft.world.item.*;
+
+public final class CombatUtil {
+    private static final Reference2FloatMap<Item> LEGACY_ITEM_DAMAGE_MAP = new Reference2FloatOpenHashMap<>();
+
+    public static float getLegacyItemDamage(Item item) {
+        return LEGACY_ITEM_DAMAGE_MAP.getFloat(item);
+    }
+
+    private static float baseToolDamage(TieredItem item) {
+        return switch (item) {
+            case SwordItem swordItem -> 4.0f;
+            case AxeItem axeItem -> 3.0f;
+            case PickaxeItem pickaxeItem -> 2.0f;
+            case ShovelItem shovelItem -> 1.0f;
+            case null, default -> 0.0f;
+        };
+    }
+
+    static {
+        LEGACY_ITEM_DAMAGE_MAP.defaultReturnValue(Float.MIN_VALUE);
+
+        for (Item item : BuiltInRegistries.ITEM) {
+            if (item instanceof TieredItem tieredItem) {
+                LEGACY_ITEM_DAMAGE_MAP.put(item, baseToolDamage(tieredItem) + tieredItem.getTier().getAttackDamageBonus());
+            }
+
+            if (item instanceof HoeItem) {
+                LEGACY_ITEM_DAMAGE_MAP.put(item, 0.0f);
+            }
+        }
+
+        //LEGACY_ITEM_DAMAGE_MAP.put(Items.TRIDENT, LEGACY_ITEM_DAMAGE_MAP.getFloat(Items.DIAMOND_SWORD));
+    }
+}
diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index 5a7f7de0bcdd3d6ed946f0d3e3100e21ff1cbea9..7d451c2924ab944e453c56a02fb02dd0b81381ef 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -299,6 +299,79 @@ 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) {
+            legacyModifier = this.getLegacyAttackModifier();
+        }
+
+        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;
+    }
+
+    private @Nullable AttributeModifier getLegacyAttackModifier() {
+        ItemStack itemstack = this.getLastHandItem(EquipmentSlot.MAINHAND);
+        net.minecraft.world.item.component.ItemAttributeModifiers defaultModifiers = itemstack.getItem().components().get(DataComponents.ATTRIBUTE_MODIFIERS);
+        if (defaultModifiers != null && !defaultModifiers.modifiers().isEmpty()) { // exists
+            double baseAttack = 0.0;
+            for (net.minecraft.world.item.component.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 null;
+                baseAttack += entry.modifier().amount();
+            }
+
+            float legacyAttack = me.samsuik.sakura.utils.CombatUtil.getLegacyItemDamage(itemstack.getItem());
+            double attackDifference = (double) legacyAttack - baseAttack;
+
+            if (baseAttack != 0.0f && legacyAttack != Float.MIN_VALUE) {
+                return new AttributeModifier(LEGACY_COMBAT_MODIFIER_ID, attackDifference, AttributeModifier.Operation.ADD_VALUE);
+            }
+        }
+        return null;
+    }
+
+    protected final float calculateLegacySharpnessDamage(ItemStack itemstack, DamageSource damageSource) {
+        net.minecraft.core.RegistryAccess registryAccess = net.minecraft.server.MinecraftServer.getServer().registryAccess();
+        net.minecraft.core.HolderLookup.RegistryLookup<Enchantment> enchantments = registryAccess.lookupOrThrow(net.minecraft.core.registries.Registries.ENCHANTMENT);
+        Holder<Enchantment> sharpness = enchantments.getOrThrow(net.minecraft.world.item.enchantment.Enchantments.SHARPNESS);
+
+        int enchantmentLevel = itemstack.getEnchantments().getLevel(sharpness);
+        ServerLevel serverLevel = (ServerLevel) this.level();
+
+        org.apache.commons.lang3.mutable.MutableFloat damage = new org.apache.commons.lang3.mutable.MutableFloat();
+        sharpness.value().modifyDamage(serverLevel, enchantmentLevel, itemstack, this, damageSource, damage);
+
+        // legacy - modern
+        return enchantmentLevel * 1.25F - damage.getValue();
+    }
+    // Sakura end - legacy combat mechanics
 
     protected LivingEntity(EntityType<? extends LivingEntity> type, Level world) {
         super(type, world);
@@ -2173,7 +2246,16 @@ 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 - Moved into actuallyHurt(DamageSource, float)
+            // 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;
@@ -3297,6 +3379,12 @@ public abstract class LivingEntity extends Entity implements Attackable {
 
                     });
                 }
+
+                // 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 1967a38277d12e09bf39af271eb6c7ed75fe0218..57f891099e7b66e75e9d8eb0f961c4395ed875ff 100644
--- a/src/main/java/net/minecraft/world/entity/player/Player.java
+++ b/src/main/java/net/minecraft/world/entity/player/Player.java
@@ -1277,14 +1277,20 @@ 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 = 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 += this.calculateLegacySharpnessDamage(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;
@@ -1312,7 +1318,7 @@ 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) {