/*
 * Copyright 2025 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this 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.
 */
// This file is automatically generated. Do not modify it.
package utils

import kotlin.math.abs

/** Utility methods for mathematical operations. */
object MathUtils {
  /**
   * The linear interpolation function.
   *
   * @return start if amount = 0 and stop if amount = 1
   */
  fun lerp(start: Double, stop: Double, amount: Double): Double {
    return (1.0 - amount) * start + amount * stop
  }

  /**
   * Sanitizes a degree measure as an integer.
   *
   * @return a degree measure between 0 (inclusive) and 360 (exclusive).
   */
  fun sanitizeDegreesInt(degrees: Int): Int {
    var degrees = degrees % 360
    if (degrees < 0) {
      degrees += 360
    }
    return degrees
  }

  /**
   * Sanitizes a degree measure as a floating-point number.
   *
   * @return a degree measure between 0.0 (inclusive) and 360.0 (exclusive).
   */
  fun sanitizeDegreesDouble(degrees: Double): Double {
    var degrees = degrees % 360.0
    if (degrees < 0) {
      degrees += 360.0
    }
    return degrees
  }

  /**
   * Sign of direction change needed to travel from one angle to another.
   *
   * For angles that are 180 degrees apart from each other, both directions have the same travel
   * distance, so either direction is shortest. The value 1.0 is returned in this case.
   *
   * @param from The angle travel starts from, in degrees.
   * @param to The angle travel ends at, in degrees.
   * @return -1 if decreasing from leads to the shortest travel distance, 1 if increasing from leads
   *   to the shortest travel distance.
   */
  fun rotationDirection(from: Double, to: Double): Double {
    val increasingDifference = sanitizeDegreesDouble(to - from)
    return if (increasingDifference <= 180.0) 1.0 else -1.0
  }

  /** Distance of two points on a circle, represented using degrees. */
  fun differenceDegrees(a: Double, b: Double): Double {
    return 180.0 - abs(abs(a - b) - 180.0)
  }

  /** Multiplies a 1x3 row vector with a 3x3 matrix. */
  fun matrixMultiply(row: DoubleArray, matrix: Array<DoubleArray>): DoubleArray {
    val a = row[0] * matrix[0][0] + row[1] * matrix[0][1] + row[2] * matrix[0][2]
    val b = row[0] * matrix[1][0] + row[1] * matrix[1][1] + row[2] * matrix[1][2]
    val c = row[0] * matrix[2][0] + row[1] * matrix[2][1] + row[2] * matrix[2][2]
    return doubleArrayOf(a, b, c)
  }
}
