/******************************************************************************
 * Copyright (C) Ultraleap, Inc. 2011-2021.                                   *
 *                                                                            *
 * Use subject to the terms of the Apache License 2.0 available at            *
 * http://www.apache.org/licenses/LICENSE-2.0, or another agreement           *
 * between Ultraleap and you, your company or other organization.             *
 ******************************************************************************/

using UnityEngine;

namespace Leap.Unity.Geometry
{

    public struct Bipyramid
    {

        public Vector3 a;
        public Vector3 b;
        public int polySegments;
        public float lengthFraction;
        public float? absoluteRadius;
        public float? radiusFraction;
        public Transform transform;
        private Matrix4x4? overrideMatrix;
        public Matrix4x4 matrix
        {
            get
            {
                if (overrideMatrix != null) { return overrideMatrix.Value; }
                if (transform != null) { return transform.localToWorldMatrix; }
                return Matrix4x4.identity;
            }
        }
        public float radius
        {
            get
            {
                if (absoluteRadius != null) { return absoluteRadius.Value; }
                if (radiusFraction != null) { return (b - a).magnitude * radiusFraction.Value; }
                else { return (b - a).magnitude * 0.125f; }
            }
        }

        public Bipyramid(Vector3 a, Vector3 b, int polySegments = 6,
          float lengthFraction = 0.5f, float? radiusFraction = null,
          float? absoluteRadius = null, Transform transform = null,
          Matrix4x4? overrideMatrix = null)
        {
            this.a = a;
            this.b = b;
            this.polySegments = polySegments;
            this.lengthFraction = lengthFraction;
            this.radiusFraction = radiusFraction;
            this.absoluteRadius = absoluteRadius;
            this.transform = transform;
            this.overrideMatrix = overrideMatrix;
        }

        /// <summary> Rig model bone defaults for a bipyramid. Can override any of
        /// the parameters like a normal bipyramid constructor. </summary>
        public static Bipyramid ModelBone(Vector3 a, Vector3 b, int polySegments = 4,
          float lengthFraction = 0.38f, float? radiusFraction = 0.0125f,
          float? absoluteRadius = null, Transform transform = null,
          Matrix4x4? overrideMatrix = null)
        {
            return new Bipyramid(a, b, polySegments: polySegments,
              lengthFraction: lengthFraction, radiusFraction: radiusFraction,
              absoluteRadius: absoluteRadius, transform: transform,
              overrideMatrix: overrideMatrix);
        }

        /// <summary> Thin directed arrow, good for adding directionality to an edge
        /// between two points. Can override any of the parameters like a normal
        /// bipyramid constructor. </summary>
        public static Bipyramid ThinArrow(Vector3 a, Vector3 b, int polySegments = 4,
          float lengthFraction = 0.3f, float? radiusFraction = null,
          float? absoluteRadius = 0.005f, Transform transform = null,
          Matrix4x4? overrideMatrix = null)
        {
            return new Bipyramid(a, b, polySegments: polySegments,
              lengthFraction: lengthFraction, radiusFraction: radiusFraction,
              absoluteRadius: absoluteRadius, transform: transform,
              overrideMatrix: overrideMatrix);
        }

        /// <summary> Arrowhead defaults for a bipyramid. Can override any of
        /// the parameters like a normal bipyramid constructor. </summary>
        public static Bipyramid Arrowhead(Vector3 a, Vector3 b, int polySegments = 6,
          float lengthFraction = 0.38f, float? radiusFraction = 0.16f,
          float? absoluteRadius = null, Transform transform = null,
          Matrix4x4? overrideMatrix = null)
        {
            return new Bipyramid(a, b, polySegments: polySegments,
              lengthFraction: lengthFraction, radiusFraction: radiusFraction,
              absoluteRadius: absoluteRadius, transform: transform,
              overrideMatrix: overrideMatrix);
        }

        public void DrawLines(System.Action<Vector3, Vector3> drawLine)
        {
            var matrix = this.matrix;
            var radius = this.radius;
            var localLength = (b - a).magnitude;
            if (localLength == 0f) { localLength = 0.0001f; }
            var localDirection = (b - a) / localLength;

            var circle = new Geometry.Circle(
              center: a + localDirection * localLength * lengthFraction,
              direction: localDirection,
              radius: radius,
              overrideMatrix: matrix
            );
            var startPos = matrix.MultiplyPoint3x4(a);
            var endPos = matrix.MultiplyPoint3x4(b);

            foreach (var point in circle.Points(polySegments))
            {
                drawLine(startPos, point);
                drawLine(point, endPos);
            }
            foreach (var edge in circle.Segments(polySegments))
            {
                drawLine(edge.a, edge.b);
            }
        }

    }

}