Code/net/minecraft/advancements/TreeNodePosition.java

package net.minecraft.advancements;

import com.google.common.collect.Lists;
import java.util.List;
import javax.annotation.Nullable;

public class TreeNodePosition {
    private final AdvancementNode node;
    @Nullable
    private final TreeNodePosition parent;
    @Nullable
    private final TreeNodePosition previousSibling;
    private final int childIndex;
    private final List<TreeNodePosition> children = Lists.newArrayList();
    private TreeNodePosition ancestor;
    @Nullable
    private TreeNodePosition thread;
    private int x;
    private float y;
    private float mod;
    private float change;
    private float shift;

    public TreeNodePosition(AdvancementNode p_297517_, @Nullable TreeNodePosition p_16568_, @Nullable TreeNodePosition p_16569_, int p_16570_, int p_16571_) {
        if (p_297517_.advancement().display().isEmpty()) {
            throw new IllegalArgumentException("Can't position an invisible advancement!");
        } else {
            this.node = p_297517_;
            this.parent = p_16568_;
            this.previousSibling = p_16569_;
            this.childIndex = p_16570_;
            this.ancestor = this;
            this.x = p_16571_;
            this.y = -1.0F;
            TreeNodePosition treenodeposition = null;

            for (AdvancementNode advancementnode : p_297517_.children()) {
                treenodeposition = this.addChild(advancementnode, treenodeposition);
            }
        }
    }

    @Nullable
    private TreeNodePosition addChild(AdvancementNode p_298340_, @Nullable TreeNodePosition p_16591_) {
        if (p_298340_.advancement().display().isPresent()) {
            p_16591_ = new TreeNodePosition(p_298340_, this, p_16591_, this.children.size() + 1, this.x + 1);
            this.children.add(p_16591_);
        } else {
            for (AdvancementNode advancementnode : p_298340_.children()) {
                p_16591_ = this.addChild(advancementnode, p_16591_);
            }
        }

        return p_16591_;
    }

    private void firstWalk() {
        if (this.children.isEmpty()) {
            if (this.previousSibling != null) {
                this.y = this.previousSibling.y + 1.0F;
            } else {
                this.y = 0.0F;
            }
        } else {
            TreeNodePosition treenodeposition = null;

            for (TreeNodePosition treenodeposition1 : this.children) {
                treenodeposition1.firstWalk();
                treenodeposition = treenodeposition1.apportion(treenodeposition == null ? treenodeposition1 : treenodeposition);
            }

            this.executeShifts();
            float f = (this.children.get(0).y + this.children.get(this.children.size() - 1).y) / 2.0F;
            if (this.previousSibling != null) {
                this.y = this.previousSibling.y + 1.0F;
                this.mod = this.y - f;
            } else {
                this.y = f;
            }
        }
    }

    private float secondWalk(float p_16576_, int p_16577_, float p_16578_) {
        this.y += p_16576_;
        this.x = p_16577_;
        if (this.y < p_16578_) {
            p_16578_ = this.y;
        }

        for (TreeNodePosition treenodeposition : this.children) {
            p_16578_ = treenodeposition.secondWalk(p_16576_ + this.mod, p_16577_ + 1, p_16578_);
        }

        return p_16578_;
    }

    private void thirdWalk(float p_16574_) {
        this.y += p_16574_;

        for (TreeNodePosition treenodeposition : this.children) {
            treenodeposition.thirdWalk(p_16574_);
        }
    }

    private void executeShifts() {
        float f = 0.0F;
        float f1 = 0.0F;

        for (int i = this.children.size() - 1; i >= 0; i--) {
            TreeNodePosition treenodeposition = this.children.get(i);
            treenodeposition.y += f;
            treenodeposition.mod += f;
            f1 += treenodeposition.change;
            f += treenodeposition.shift + f1;
        }
    }

    @Nullable
    private TreeNodePosition previousOrThread() {
        if (this.thread != null) {
            return this.thread;
        } else {
            return !this.children.isEmpty() ? this.children.get(0) : null;
        }
    }

    @Nullable
    private TreeNodePosition nextOrThread() {
        if (this.thread != null) {
            return this.thread;
        } else {
            return !this.children.isEmpty() ? this.children.get(this.children.size() - 1) : null;
        }
    }

    private TreeNodePosition apportion(TreeNodePosition p_16580_) {
        if (this.previousSibling == null) {
            return p_16580_;
        } else {
            TreeNodePosition treenodeposition = this;
            TreeNodePosition treenodeposition1 = this;
            TreeNodePosition treenodeposition2 = this.previousSibling;
            TreeNodePosition treenodeposition3 = this.parent.children.get(0);
            float f = this.mod;
            float f1 = this.mod;
            float f2 = treenodeposition2.mod;

            float f3;
            for (f3 = treenodeposition3.mod; treenodeposition2.nextOrThread() != null && treenodeposition.previousOrThread() != null; f1 += treenodeposition1.mod) {
                treenodeposition2 = treenodeposition2.nextOrThread();
                treenodeposition = treenodeposition.previousOrThread();
                treenodeposition3 = treenodeposition3.previousOrThread();
                treenodeposition1 = treenodeposition1.nextOrThread();
                treenodeposition1.ancestor = this;
                float f4 = treenodeposition2.y + f2 - (treenodeposition.y + f) + 1.0F;
                if (f4 > 0.0F) {
                    treenodeposition2.getAncestor(this, p_16580_).moveSubtree(this, f4);
                    f += f4;
                    f1 += f4;
                }

                f2 += treenodeposition2.mod;
                f += treenodeposition.mod;
                f3 += treenodeposition3.mod;
            }

            if (treenodeposition2.nextOrThread() != null && treenodeposition1.nextOrThread() == null) {
                treenodeposition1.thread = treenodeposition2.nextOrThread();
                treenodeposition1.mod += f2 - f1;
            } else {
                if (treenodeposition.previousOrThread() != null && treenodeposition3.previousOrThread() == null) {
                    treenodeposition3.thread = treenodeposition.previousOrThread();
                    treenodeposition3.mod += f - f3;
                }

                p_16580_ = this;
            }

            return p_16580_;
        }
    }

    private void moveSubtree(TreeNodePosition p_16582_, float p_16583_) {
        float f = p_16582_.childIndex - this.childIndex;
        if (f != 0.0F) {
            p_16582_.change -= p_16583_ / f;
            this.change += p_16583_ / f;
        }

        p_16582_.shift += p_16583_;
        p_16582_.y += p_16583_;
        p_16582_.mod += p_16583_;
    }

    private TreeNodePosition getAncestor(TreeNodePosition p_16585_, TreeNodePosition p_16586_) {
        return this.ancestor != null && p_16585_.parent.children.contains(this.ancestor) ? this.ancestor : p_16586_;
    }

    private void finalizePosition() {
        this.node.advancement().display().ifPresent(p_298323_ -> p_298323_.setLocation(this.x, this.y));
        if (!this.children.isEmpty()) {
            for (TreeNodePosition treenodeposition : this.children) {
                treenodeposition.finalizePosition();
            }
        }
    }

    public static void run(AdvancementNode p_299150_) {
        if (p_299150_.advancement().display().isEmpty()) {
            throw new IllegalArgumentException("Can't position children of an invisible root!");
        } else {
            TreeNodePosition treenodeposition = new TreeNodePosition(p_299150_, null, null, 1, 0);
            treenodeposition.firstWalk();
            float f = treenodeposition.secondWalk(0.0F, 0, treenodeposition.y);
            if (f < 0.0F) {
                treenodeposition.thirdWalk(-f);
            }

            treenodeposition.finalizePosition();
        }
    }
}