/*
 * Copyright 2019-2025 Andrey Pokidov <andrey.pokidov@gmail.com>
 *
 * 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.
 */

using System;

/*
 * Author: Andrey Pokidov
 * Date: 1 Feb 2019
 */

namespace Geometry
{
    public static class SPAngle
    {
        public const float PI = 3.1415926536f;
        public const float TWO_PI = 6.2831853072f;
        public const float HALF_OF_PI = 1.5707963268f;
        public const float THIRD_OF_PI = 1.0471975512f;
        public const float FOURTH_OF_PI = 0.7853981634f;
        public const float SIXTH_OF_PI = 0.5235987756f;

        public const float DEGREES_IN_RADIAN = 57.295779513f;
        public const float TURNS_IN_RADIAN = 0.1591549431f;
        public const float RADIANS_IN_DEGREE = 1.745329252E-2f;
        public const float TURNS_IN_DEGREE = 2.7777777778E-3f;

        public static float RadiansToDegrees(float radians)
        {
            return radians * DEGREES_IN_RADIAN;
        }

        public static float RadiansToTurns(float radians)
        {
            return radians * TURNS_IN_RADIAN;
        }

        public static float DegreesToRadians(float degrees)
        {
            return degrees * RADIANS_IN_DEGREE;
        }

        public static float DegreesToTurns(float degrees)
        {
            return degrees * TURNS_IN_DEGREE;
        }

        public static float TurnsToRadians(float turns)
        {
            return turns * TWO_PI;
        }

        public static float TurnsToDegrees(float turns)
        {
            return turns * 360.0f;
        }

        public static float ConvertFromRadians(float radians, AngleUnit toUnit)
        {
            if (toUnit == AngleUnit.DEGREES)
            {
                return radians * DEGREES_IN_RADIAN;
            }

            if (toUnit == AngleUnit.TURNS)
            {
                return radians * TURNS_IN_RADIAN;
            }

            return radians;
        }

        public static float ConvertFromDegrees(float degrees, AngleUnit toUnit)
        {
            if (toUnit == AngleUnit.RADIANS)
            {
                return degrees * RADIANS_IN_DEGREE;
            }

            if (toUnit == AngleUnit.TURNS)
            {
                return degrees * TURNS_IN_DEGREE;
            }

            return degrees;
        }

        public static float ConvertFromTurns(float turns, AngleUnit toUnit)
        {
            if (toUnit == AngleUnit.RADIANS)
            {
                return turns * TWO_PI;
            }

            if (toUnit == AngleUnit.DEGREES)
            {
                return turns * 360.0f;
            }

            return turns;
        }

        public static float ConvertToRadians(float angle, AngleUnit unit)
        {
            if (unit == AngleUnit.DEGREES)
            {
                return angle * RADIANS_IN_DEGREE;
            }

            if (unit == AngleUnit.TURNS)
            {
                return angle * TWO_PI;
            }

            return angle;
        }

        public static float ConvertToDegrees(float angle, AngleUnit unit)
        {
            if (unit == AngleUnit.RADIANS)
            {
                return angle * DEGREES_IN_RADIAN;
            }

            if (unit == AngleUnit.TURNS)
            {
                return angle * 360.0f;
            }

            return angle;
        }

        public static float ConvertToTurns(float angle, AngleUnit unit)
        {
            if (unit == AngleUnit.RADIANS)
            {
                return angle * TURNS_IN_RADIAN;
            }

            if (unit == AngleUnit.DEGREES)
            {
                return angle * TURNS_IN_DEGREE;
            }

            return angle;
        }

        public static float GetFullCircle(AngleUnit unit)
        {
            if (unit == AngleUnit.RADIANS)
            {
                return TWO_PI;
            }
        
            if (unit == AngleUnit.DEGREES)
            {
                return 360.0f;
            }
        
            return 1.0f;
        }
    
        public static float GetHalfCircle(AngleUnit unit)
        {
            if (unit == AngleUnit.RADIANS)
            {
                return PI;
            }
        
            if (unit == AngleUnit.DEGREES)
            {
                return 180.0f;
            }
        
            return 0.5f;
        }
    
        public static float GetQuarterCircle(AngleUnit unit)
        {
            if (unit == AngleUnit.RADIANS)
            {
                return HALF_OF_PI;
            }
        
            if (unit == AngleUnit.DEGREES)
            {
                return 90.0f;
            }
        
            return 0.25f;
        }

        public static float NormalizeRadians(float radians, AngleRange range)
        {
            if (range == AngleRange.UNSIGNED_RANGE)
            {
                if (0.0 <= radians && radians < TWO_PI)
                {
                    return radians;
                }

            }
            else
            {
                if (-PI < radians && radians <= PI)
                {
                    return radians;
                }
            }

            float turns = radians * TURNS_IN_RADIAN;

            turns -= MathF.Floor(turns);

            if (range == AngleRange.SIGNED_RANGE && turns > 0.5f)
            {
                turns -= 1.0f;
            }

            return turns * TWO_PI;
        }

        public static float NormalizeDegrees(float radians, AngleRange range)
        {
            if (range == AngleRange.UNSIGNED_RANGE)
            {
                if (0.0f <= radians && radians < 360.0f)
                {
                    return radians;
                }
            }
            else
            {
                if (-180.0f < radians && radians <= 180.0f)
                {
                    return radians;
                }
            }

            float turns = radians * TURNS_IN_DEGREE;

            turns -= MathF.Floor(turns);

            if (range == AngleRange.SIGNED_RANGE && turns > 0.5f)
            {
                turns -= 1.0f;
            }

            return turns * 360.0f;
        }

        public static float NormalizeTurns(float turns, AngleRange range)
        {
            if (range == AngleRange.UNSIGNED_RANGE)
            {
                if (0.0f <= turns && turns < 1.0f)
                {
                    return turns;
                }
            }
            else
            {
                if (-0.5f < turns && turns <= 0.5f)
                {
                    return turns;
                }
            }

            float rest = turns - MathF.Floor(turns);

            if (range == AngleRange.SIGNED_RANGE && rest > 0.5f)
            {
                rest -= 1.0f;
            }

            return rest;
        }

        public static float Normalize(float angle, AngleUnit unit, AngleRange range)
        {
            if (unit == AngleUnit.RADIANS)
            {
                return NormalizeRadians(angle, range);
            }

            if (unit == AngleUnit.DEGREES)
            {
                return NormalizeDegrees(angle, range);
            }

            return NormalizeTurns(angle, range);
        }
    }
}