/* This file contains an adaptation of code from The Android Open Source
 * Project found at <https://cs.android.com/>
 * For the avoidance of doubt, this file is still licensed under the terms
 * of OneConfig's Licensing.
 *
 *                 LICENSE NOTICE FOR ADAPTED CODE
 *
 * Copyright 2019 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use the file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Significant changes (as required by the Apache 2.0):
 * - Changed variable names
 * - Code adapted from Kotlin to Java
 * - Removed variables defining premade easing functions
 * - Added constructor for JDT and OneConfig's animation system
 *
 * As per the terms of the Apache 2.0 License, a copy of the License
 * is found at `src/main/resources/licenses/Android-License.txt`.
 */

package cc.polyfrost.oneconfig.gui.animations;

public class CubicBezier extends Animation {
    private static final float CubicErrorBound = 0.001f;
    protected final float P0;
    protected final float P1;
    protected final float P2;
    protected final float P3;

    /**
     * @param P0       First control point X
     * @param P1       First control point Y
     * @param P2       Second control point X
     * @param P3       Second control point Y
     * @param duration The duration of the animation
     * @param start    The start of the animation
     * @param end      The end of the animation
     * @param reverse  Reverse the animation
     */
    public CubicBezier(float P0, float P1, float P2, float P3, float duration, float start, float end, boolean reverse) {
        super(duration, start, end, reverse);
        this.P0 = P0;
        this.P1 = P1;
        this.P2 = P2;
        this.P3 = P3;
    }

    /**
     * This constructor should be used with JDT's getCubicBezier method
     *
     * @param points   The control points
     * @param duration The duration of the animation
     * @param start    The start of the animation
     * @param end      The end of the animation
     * @param reverse  Reverse the animation
     */
    public CubicBezier(float[] points, float duration, float start, float end, boolean reverse) {
        this(points[0], points[1], points[2], points[3], duration, start, end, reverse);
    }

    /**
     * Adapted from <a href="https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/animation/animation-core/src/commonMain/kotlin/androidx/compose/animation/core/Easing.kt">Android</a>
     * Under Apache 2.0 license
     *
     * @param x The current point
     * @return The value
     */
    @Override
    protected float animate(float x) {
        float start = 0.0f;
        float end = 1.0f;
        while (true) {
            float midpoint = (start + end) / 2;
            float estimate = evaluateCubic(P0, P2, midpoint);
            if (Math.abs(x - estimate) < CubicErrorBound)
                return evaluateCubic(P1, P3, midpoint);
            if (estimate < x) start = midpoint;
            else end = midpoint;
        }
    }

    /**
     * Adapted from <a href="https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/animation/animation-core/src/commonMain/kotlin/androidx/compose/animation/core/Easing.kt">Android</a>
     * Under Apache 2.0 license
     */
    private float evaluateCubic(float a, float b, float m) {
        return 3 * a * (1 - m) * (1 - m) * m +
                3 * b * (1 - m) * /*    */ m * m +
                /*                      */ m * m * m;
    }
}