Code/net/minecraft/world/entity/boss/enderdragon/phases/DragonHoldingPatternPhase.java

package net.minecraft.world.entity.boss.enderdragon.phases;

import javax.annotation.Nullable;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Vec3i;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.world.damagesource.DamageSource;
import net.minecraft.world.entity.ai.targeting.TargetingConditions;
import net.minecraft.world.entity.boss.enderdragon.EndCrystal;
import net.minecraft.world.entity.boss.enderdragon.EnderDragon;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.level.levelgen.Heightmap;
import net.minecraft.world.level.levelgen.feature.EndPodiumFeature;
import net.minecraft.world.level.pathfinder.Path;
import net.minecraft.world.phys.Vec3;

public class DragonHoldingPatternPhase extends AbstractDragonPhaseInstance {
    private static final TargetingConditions NEW_TARGET_TARGETING = TargetingConditions.forCombat().ignoreLineOfSight();
    @Nullable
    private Path currentPath;
    @Nullable
    private Vec3 targetLocation;
    private boolean clockwise;

    public DragonHoldingPatternPhase(EnderDragon p_31230_) {
        super(p_31230_);
    }

    @Override
    public EnderDragonPhase<DragonHoldingPatternPhase> getPhase() {
        return EnderDragonPhase.HOLDING_PATTERN;
    }

    @Override
    public void doServerTick(ServerLevel p_366645_) {
        double d0 = this.targetLocation == null ? 0.0 : this.targetLocation.distanceToSqr(this.dragon.getX(), this.dragon.getY(), this.dragon.getZ());
        if (d0 < 100.0 || d0 > 22500.0 || this.dragon.horizontalCollision || this.dragon.verticalCollision) {
            this.findNewTarget(p_366645_);
        }
    }

    @Override
    public void begin() {
        this.currentPath = null;
        this.targetLocation = null;
    }

    @Nullable
    @Override
    public Vec3 getFlyTargetLocation() {
        return this.targetLocation;
    }

    private void findNewTarget(ServerLevel p_369217_) {
        if (this.currentPath != null && this.currentPath.isDone()) {
            BlockPos blockpos = p_369217_.getHeightmapPos(Heightmap.Types.MOTION_BLOCKING_NO_LEAVES, EndPodiumFeature.getLocation(this.dragon.getFightOrigin()));
            int i = this.dragon.getDragonFight() == null ? 0 : this.dragon.getDragonFight().getCrystalsAlive();
            if (this.dragon.getRandom().nextInt(i + 3) == 0) {
                this.dragon.getPhaseManager().setPhase(EnderDragonPhase.LANDING_APPROACH);
                return;
            }

            Player player = p_369217_.getNearestPlayer(NEW_TARGET_TARGETING, this.dragon, blockpos.getX(), blockpos.getY(), blockpos.getZ());
            double d0;
            if (player != null) {
                d0 = blockpos.distToCenterSqr(player.position()) / 512.0;
            } else {
                d0 = 64.0;
            }

            if (player != null && (this.dragon.getRandom().nextInt((int)(d0 + 2.0)) == 0 || this.dragon.getRandom().nextInt(i + 2) == 0)) {
                this.strafePlayer(player);
                return;
            }
        }

        if (this.currentPath == null || this.currentPath.isDone()) {
            int j = this.dragon.findClosestNode();
            int k = j;
            if (this.dragon.getRandom().nextInt(8) == 0) {
                this.clockwise = !this.clockwise;
                k = j + 6;
            }

            if (this.clockwise) {
                k++;
            } else {
                k--;
            }

            if (this.dragon.getDragonFight() != null && this.dragon.getDragonFight().getCrystalsAlive() >= 0) {
                k %= 12;
                if (k < 0) {
                    k += 12;
                }
            } else {
                k -= 12;
                k &= 7;
                k += 12;
            }

            this.currentPath = this.dragon.findPath(j, k, null);
            if (this.currentPath != null) {
                this.currentPath.advance();
            }
        }

        this.navigateToNextPathNode();
    }

    private void strafePlayer(Player p_31237_) {
        this.dragon.getPhaseManager().setPhase(EnderDragonPhase.STRAFE_PLAYER);
        this.dragon.getPhaseManager().getPhase(EnderDragonPhase.STRAFE_PLAYER).setTarget(p_31237_);
    }

    private void navigateToNextPathNode() {
        if (this.currentPath != null && !this.currentPath.isDone()) {
            Vec3i vec3i = this.currentPath.getNextNodePos();
            this.currentPath.advance();
            double d0 = vec3i.getX();
            double d1 = vec3i.getZ();

            double d2;
            do {
                d2 = vec3i.getY() + this.dragon.getRandom().nextFloat() * 20.0F;
            } while (d2 < vec3i.getY());

            this.targetLocation = new Vec3(d0, d2, d1);
        }
    }

    @Override
    public void onCrystalDestroyed(EndCrystal p_31232_, BlockPos p_31233_, DamageSource p_31234_, @Nullable Player p_31235_) {
        if (p_31235_ != null && this.dragon.canAttack(p_31235_)) {
            this.strafePlayer(p_31235_);
        }
    }
}