minecraft-src/net/minecraft/world/damagesource/CombatTracker.java

package net.minecraft.world.damagesource;

import com.google.common.collect.Lists;
import java.util.List;
import java.util.Objects;
import net.minecraft.core.component.DataComponents;
import net.minecraft.network.chat.ClickEvent;
import net.minecraft.network.chat.Component;
import net.minecraft.network.chat.ComponentUtils;
import net.minecraft.network.chat.HoverEvent;
import net.minecraft.network.chat.Style;
import net.minecraft.tags.DamageTypeTags;
import net.minecraft.util.CommonLinks;
import net.minecraft.world.entity.Entity;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.item.ItemStack;
import org.jetbrains.annotations.Nullable;

public class CombatTracker {
	public static final int RESET_DAMAGE_STATUS_TIME = 100;
	public static final int RESET_COMBAT_STATUS_TIME = 300;
	private static final Style INTENTIONAL_GAME_DESIGN_STYLE = Style.EMPTY
		.withClickEvent(new ClickEvent.OpenUrl(CommonLinks.INTENTIONAL_GAME_DESIGN_BUG))
		.withHoverEvent(new HoverEvent.ShowText(Component.literal("MCPE-28723")));
	private final List<CombatEntry> entries = Lists.<CombatEntry>newArrayList();
	private final LivingEntity mob;
	private int lastDamageTime;
	private int combatStartTime;
	private int combatEndTime;
	private boolean inCombat;
	private boolean takingDamage;

	public CombatTracker(LivingEntity mob) {
		this.mob = mob;
	}

	public void recordDamage(DamageSource source, float damage) {
		this.recheckStatus();
		FallLocation fallLocation = FallLocation.getCurrentFallLocation(this.mob);
		CombatEntry combatEntry = new CombatEntry(source, damage, fallLocation, (float)this.mob.fallDistance);
		this.entries.add(combatEntry);
		this.lastDamageTime = this.mob.tickCount;
		this.takingDamage = true;
		if (!this.inCombat && this.mob.isAlive() && shouldEnterCombat(source)) {
			this.inCombat = true;
			this.combatStartTime = this.mob.tickCount;
			this.combatEndTime = this.combatStartTime;
			this.mob.onEnterCombat();
		}
	}

	private static boolean shouldEnterCombat(DamageSource source) {
		return source.getEntity() instanceof LivingEntity;
	}

	private Component getMessageForAssistedFall(Entity entity, Component entityDisplayName, String hasWeaponTranslationKey, String noWeaponTranslationKey) {
		ItemStack itemStack = entity instanceof LivingEntity livingEntity ? livingEntity.getMainHandItem() : ItemStack.EMPTY;
		return !itemStack.isEmpty() && itemStack.has(DataComponents.CUSTOM_NAME)
			? Component.translatable(hasWeaponTranslationKey, this.mob.getDisplayName(), entityDisplayName, itemStack.getDisplayName())
			: Component.translatable(noWeaponTranslationKey, this.mob.getDisplayName(), entityDisplayName);
	}

	private Component getFallMessage(CombatEntry combatEntry, @Nullable Entity entity) {
		DamageSource damageSource = combatEntry.source();
		if (!damageSource.is(DamageTypeTags.IS_FALL) && !damageSource.is(DamageTypeTags.ALWAYS_MOST_SIGNIFICANT_FALL)) {
			Component component = getDisplayName(entity);
			Entity entity2 = damageSource.getEntity();
			Component component2 = getDisplayName(entity2);
			if (component2 != null && !component2.equals(component)) {
				return this.getMessageForAssistedFall(entity2, component2, "death.fell.assist.item", "death.fell.assist");
			} else {
				return (Component)(component != null
					? this.getMessageForAssistedFall(entity, component, "death.fell.finish.item", "death.fell.finish")
					: Component.translatable("death.fell.killer", this.mob.getDisplayName()));
			}
		} else {
			FallLocation fallLocation = (FallLocation)Objects.requireNonNullElse(combatEntry.fallLocation(), FallLocation.GENERIC);
			return Component.translatable(fallLocation.languageKey(), this.mob.getDisplayName());
		}
	}

	@Nullable
	private static Component getDisplayName(@Nullable Entity entity) {
		return entity == null ? null : entity.getDisplayName();
	}

	public Component getDeathMessage() {
		if (this.entries.isEmpty()) {
			return Component.translatable("death.attack.generic", this.mob.getDisplayName());
		} else {
			CombatEntry combatEntry = (CombatEntry)this.entries.get(this.entries.size() - 1);
			DamageSource damageSource = combatEntry.source();
			CombatEntry combatEntry2 = this.getMostSignificantFall();
			DeathMessageType deathMessageType = damageSource.type().deathMessageType();
			if (deathMessageType == DeathMessageType.FALL_VARIANTS && combatEntry2 != null) {
				return this.getFallMessage(combatEntry2, damageSource.getEntity());
			} else if (deathMessageType == DeathMessageType.INTENTIONAL_GAME_DESIGN) {
				String string = "death.attack." + damageSource.getMsgId();
				Component component = ComponentUtils.wrapInSquareBrackets(Component.translatable(string + ".link")).withStyle(INTENTIONAL_GAME_DESIGN_STYLE);
				return Component.translatable(string + ".message", this.mob.getDisplayName(), component);
			} else {
				return damageSource.getLocalizedDeathMessage(this.mob);
			}
		}
	}

	@Nullable
	private CombatEntry getMostSignificantFall() {
		CombatEntry combatEntry = null;
		CombatEntry combatEntry2 = null;
		float f = 0.0F;
		float g = 0.0F;

		for (int i = 0; i < this.entries.size(); i++) {
			CombatEntry combatEntry3 = (CombatEntry)this.entries.get(i);
			CombatEntry combatEntry4 = i > 0 ? (CombatEntry)this.entries.get(i - 1) : null;
			DamageSource damageSource = combatEntry3.source();
			boolean bl = damageSource.is(DamageTypeTags.ALWAYS_MOST_SIGNIFICANT_FALL);
			float h = bl ? Float.MAX_VALUE : combatEntry3.fallDistance();
			if ((damageSource.is(DamageTypeTags.IS_FALL) || bl) && h > 0.0F && (combatEntry == null || h > g)) {
				if (i > 0) {
					combatEntry = combatEntry4;
				} else {
					combatEntry = combatEntry3;
				}

				g = h;
			}

			if (combatEntry3.fallLocation() != null && (combatEntry2 == null || combatEntry3.damage() > f)) {
				combatEntry2 = combatEntry3;
				f = combatEntry3.damage();
			}
		}

		if (g > 5.0F && combatEntry != null) {
			return combatEntry;
		} else {
			return f > 5.0F && combatEntry2 != null ? combatEntry2 : null;
		}
	}

	public int getCombatDuration() {
		return this.inCombat ? this.mob.tickCount - this.combatStartTime : this.combatEndTime - this.combatStartTime;
	}

	/**
	 * Resets this trackers list of combat entries
	 */
	public void recheckStatus() {
		int i = this.inCombat ? 300 : 100;
		if (this.takingDamage && (!this.mob.isAlive() || this.mob.tickCount - this.lastDamageTime > i)) {
			boolean bl = this.inCombat;
			this.takingDamage = false;
			this.inCombat = false;
			this.combatEndTime = this.mob.tickCount;
			if (bl) {
				this.mob.onLeaveCombat();
			}

			this.entries.clear();
		}
	}
}