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

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

import com.mojang.logging.LogUtils;
import javax.annotation.Nullable;
import net.minecraft.core.Vec3i;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.util.Mth;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.entity.boss.enderdragon.EnderDragon;
import net.minecraft.world.entity.projectile.DragonFireball;
import net.minecraft.world.level.pathfinder.Node;
import net.minecraft.world.level.pathfinder.Path;
import net.minecraft.world.phys.Vec3;
import org.slf4j.Logger;

public class DragonStrafePlayerPhase extends AbstractDragonPhaseInstance {
    private static final Logger LOGGER = LogUtils.getLogger();
    private static final int FIREBALL_CHARGE_AMOUNT = 5;
    private int fireballCharge;
    @Nullable
    private Path currentPath;
    @Nullable
    private Vec3 targetLocation;
    @Nullable
    private LivingEntity attackTarget;
    private boolean holdingPatternClockwise;

    public DragonStrafePlayerPhase(EnderDragon p_31357_) {
        super(p_31357_);
    }

    @Override
    public void doServerTick(ServerLevel p_362629_) {
        if (this.attackTarget == null) {
            LOGGER.warn("Skipping player strafe phase because no player was found");
            this.dragon.getPhaseManager().setPhase(EnderDragonPhase.HOLDING_PATTERN);
        } else {
            if (this.currentPath != null && this.currentPath.isDone()) {
                double d0 = this.attackTarget.getX();
                double d1 = this.attackTarget.getZ();
                double d2 = d0 - this.dragon.getX();
                double d3 = d1 - this.dragon.getZ();
                double d4 = Math.sqrt(d2 * d2 + d3 * d3);
                double d5 = Math.min(0.4F + d4 / 80.0 - 1.0, 10.0);
                this.targetLocation = new Vec3(d0, this.attackTarget.getY() + d5, d1);
            }

            double d12 = this.targetLocation == null ? 0.0 : this.targetLocation.distanceToSqr(this.dragon.getX(), this.dragon.getY(), this.dragon.getZ());
            if (d12 < 100.0 || d12 > 22500.0) {
                this.findNewTarget();
            }

            double d13 = 64.0;
            if (this.attackTarget.distanceToSqr(this.dragon) < 4096.0) {
                if (this.dragon.hasLineOfSight(this.attackTarget)) {
                    this.fireballCharge++;
                    Vec3 vec32 = new Vec3(this.attackTarget.getX() - this.dragon.getX(), 0.0, this.attackTarget.getZ() - this.dragon.getZ())
                        .normalize();
                    Vec3 vec3 = new Vec3(
                            Mth.sin(this.dragon.getYRot() * (float) (Math.PI / 180.0)),
                            0.0,
                            -Mth.cos(this.dragon.getYRot() * (float) (Math.PI / 180.0))
                        )
                        .normalize();
                    float f1 = (float)vec3.dot(vec32);
                    float f = (float)(Math.acos(f1) * 180.0F / (float)Math.PI);
                    f += 0.5F;
                    if (this.fireballCharge >= 5 && f >= 0.0F && f < 10.0F) {
                        double d14 = 1.0;
                        Vec3 vec33 = this.dragon.getViewVector(1.0F);
                        double d6 = this.dragon.head.getX() - vec33.x * 1.0;
                        double d7 = this.dragon.head.getY(0.5) + 0.5;
                        double d8 = this.dragon.head.getZ() - vec33.z * 1.0;
                        double d9 = this.attackTarget.getX() - d6;
                        double d10 = this.attackTarget.getY(0.5) - d7;
                        double d11 = this.attackTarget.getZ() - d8;
                        Vec3 vec31 = new Vec3(d9, d10, d11);
                        if (!this.dragon.isSilent()) {
                            p_362629_.levelEvent(null, 1017, this.dragon.blockPosition(), 0);
                        }

                        DragonFireball dragonfireball = new DragonFireball(p_362629_, this.dragon, vec31.normalize());
                        dragonfireball.snapTo(d6, d7, d8, 0.0F, 0.0F);
                        p_362629_.addFreshEntity(dragonfireball);
                        this.fireballCharge = 0;
                        if (this.currentPath != null) {
                            while (!this.currentPath.isDone()) {
                                this.currentPath.advance();
                            }
                        }

                        this.dragon.getPhaseManager().setPhase(EnderDragonPhase.HOLDING_PATTERN);
                    }
                } else if (this.fireballCharge > 0) {
                    this.fireballCharge--;
                }
            } else if (this.fireballCharge > 0) {
                this.fireballCharge--;
            }
        }
    }

    private void findNewTarget() {
        if (this.currentPath == null || this.currentPath.isDone()) {
            int i = this.dragon.findClosestNode();
            int j = i;
            if (this.dragon.getRandom().nextInt(8) == 0) {
                this.holdingPatternClockwise = !this.holdingPatternClockwise;
                j = i + 6;
            }

            if (this.holdingPatternClockwise) {
                j++;
            } else {
                j--;
            }

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

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

        this.navigateToNextPathNode();
    }

    private void navigateToNextPathNode() {
        if (this.currentPath != null && !this.currentPath.isDone()) {
            Vec3i vec3i = this.currentPath.getNextNodePos();
            this.currentPath.advance();
            double d0 = vec3i.getX();
            double d2 = vec3i.getZ();

            double d1;
            do {
                d1 = vec3i.getY() + this.dragon.getRandom().nextFloat() * 20.0F;
            } while (d1 < vec3i.getY());

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

    @Override
    public void begin() {
        this.fireballCharge = 0;
        this.targetLocation = null;
        this.currentPath = null;
        this.attackTarget = null;
    }

    public void setTarget(LivingEntity p_31359_) {
        this.attackTarget = p_31359_;
        int i = this.dragon.findClosestNode();
        int j = this.dragon.findClosestNode(this.attackTarget.getX(), this.attackTarget.getY(), this.attackTarget.getZ());
        int k = this.attackTarget.getBlockX();
        int l = this.attackTarget.getBlockZ();
        double d0 = k - this.dragon.getX();
        double d1 = l - this.dragon.getZ();
        double d2 = Math.sqrt(d0 * d0 + d1 * d1);
        double d3 = Math.min(0.4F + d2 / 80.0 - 1.0, 10.0);
        int i1 = Mth.floor(this.attackTarget.getY() + d3);
        Node node = new Node(k, i1, l);
        this.currentPath = this.dragon.findPath(i, j, node);
        if (this.currentPath != null) {
            this.currentPath.advance();
            this.navigateToNextPathNode();
        }
    }

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

    @Override
    public EnderDragonPhase<DragonStrafePlayerPhase> getPhase() {
        return EnderDragonPhase.STRAFE_PLAYER;
    }
}