/*
 * Decompiled with CFR 0.152.
 * 
 * Could not load the following classes:
 *  org.jspecify.annotations.Nullable
 */
package net.minecraft.world.entity;

import java.util.Objects;
import java.util.function.Consumer;
import net.minecraft.util.Mth;
import net.minecraft.world.entity.Entity;
import net.minecraft.world.phys.Vec2;
import net.minecraft.world.phys.Vec3;
import org.jspecify.annotations.Nullable;

public class InterpolationHandler {
    public static final int DEFAULT_INTERPOLATION_STEPS = 3;
    private final Entity entity;
    private int interpolationSteps;
    private final InterpolationData interpolationData = new InterpolationData(0, Vec3.ZERO, 0.0f, 0.0f);
    private @Nullable Vec3 previousTickPosition;
    private @Nullable Vec2 previousTickRot;
    private final @Nullable Consumer<InterpolationHandler> onInterpolationStart;

    public InterpolationHandler(Entity entity) {
        this(entity, 3, null);
    }

    public InterpolationHandler(Entity entity, int interpolationSteps) {
        this(entity, interpolationSteps, null);
    }

    public InterpolationHandler(Entity entity, @Nullable Consumer<InterpolationHandler> onInterpolationStart) {
        this(entity, 3, onInterpolationStart);
    }

    public InterpolationHandler(Entity entity, int interpolationSteps, @Nullable Consumer<InterpolationHandler> onInterpolationStart) {
        this.interpolationSteps = interpolationSteps;
        this.entity = entity;
        this.onInterpolationStart = onInterpolationStart;
    }

    public Vec3 position() {
        return this.interpolationData.steps > 0 ? this.interpolationData.position : this.entity.position();
    }

    public float yRot() {
        return this.interpolationData.steps > 0 ? this.interpolationData.yRot : this.entity.getYRot();
    }

    public float xRot() {
        return this.interpolationData.steps > 0 ? this.interpolationData.xRot : this.entity.getXRot();
    }

    public void interpolateTo(Vec3 position, float yRot, float xRot) {
        if (this.interpolationSteps == 0) {
            this.entity.snapTo(position, yRot, xRot);
            this.cancel();
            return;
        }
        if (this.hasActiveInterpolation() && Objects.equals(Float.valueOf(this.yRot()), Float.valueOf(yRot)) && Objects.equals(Float.valueOf(this.xRot()), Float.valueOf(xRot)) && Objects.equals(this.position(), position)) {
            return;
        }
        this.interpolationData.steps = this.interpolationSteps;
        this.interpolationData.position = position;
        this.interpolationData.yRot = yRot;
        this.interpolationData.xRot = xRot;
        this.previousTickPosition = this.entity.position();
        this.previousTickRot = new Vec2(this.entity.getXRot(), this.entity.getYRot());
        if (this.onInterpolationStart != null) {
            this.onInterpolationStart.accept(this);
        }
    }

    public boolean hasActiveInterpolation() {
        return this.interpolationData.steps > 0;
    }

    public void setInterpolationLength(int steps) {
        this.interpolationSteps = steps;
    }

    public void interpolate() {
        if (!this.hasActiveInterpolation()) {
            this.cancel();
            return;
        }
        double alpha = 1.0 / (double)this.interpolationData.steps;
        if (this.previousTickPosition != null) {
            Vec3 deltaSinceLastInterpolation = this.entity.position().subtract(this.previousTickPosition);
            if (this.entity.level().noCollision(this.entity, this.entity.makeBoundingBox(this.interpolationData.position.add(deltaSinceLastInterpolation)))) {
                this.interpolationData.addDelta(deltaSinceLastInterpolation);
            }
        }
        if (this.previousTickRot != null) {
            float deltaYRotSinceLastInterpolation = this.entity.getYRot() - this.previousTickRot.y;
            float deltaXRotSinceLastInterpolation = this.entity.getXRot() - this.previousTickRot.x;
            this.interpolationData.addRotation(deltaYRotSinceLastInterpolation, deltaXRotSinceLastInterpolation);
        }
        double x = Mth.lerp(alpha, this.entity.getX(), this.interpolationData.position.x);
        double y = Mth.lerp(alpha, this.entity.getY(), this.interpolationData.position.y);
        double z = Mth.lerp(alpha, this.entity.getZ(), this.interpolationData.position.z);
        Vec3 newPosition = new Vec3(x, y, z);
        float newYRot = (float)Mth.rotLerp(alpha, (double)this.entity.getYRot(), (double)this.interpolationData.yRot);
        float newXRot = (float)Mth.lerp(alpha, (double)this.entity.getXRot(), (double)this.interpolationData.xRot);
        this.entity.setPos(newPosition);
        this.entity.setRot(newYRot, newXRot);
        this.interpolationData.decrease();
        this.previousTickPosition = newPosition;
        this.previousTickRot = new Vec2(this.entity.getXRot(), this.entity.getYRot());
    }

    public void cancel() {
        this.interpolationData.steps = 0;
        this.previousTickPosition = null;
        this.previousTickRot = null;
    }

    private static class InterpolationData {
        protected int steps;
        Vec3 position;
        float yRot;
        float xRot;

        private InterpolationData(int steps, Vec3 position, float yRot, float xRot) {
            this.steps = steps;
            this.position = position;
            this.yRot = yRot;
            this.xRot = xRot;
        }

        public void decrease() {
            --this.steps;
        }

        public void addDelta(Vec3 delta) {
            this.position = this.position.add(delta);
        }

        public void addRotation(float yRot, float xRot) {
            this.yRot += yRot;
            this.xRot += xRot;
        }
    }
}