/******************************************************************************
 * 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 Leap.Unity.Infix;
using Leap.Unity.RuntimeGizmos;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace Leap.Unity.Geometry
{

    public struct LocalSegment3
    {

        public Vector3 a, b;

        public LocalSegment3(Vector3 a, Vector3 b)
        {
            this.a = a;
            this.b = b;
        }

        /// <summary>
        /// Given a point _on the segment_, parameterizes that point into a value such that
        /// a + (b - a).magnitude * value = b.
        /// </summary>
        public float Parameterize(Vector3 pointOnSegment)
        {
            if ((a - b).sqrMagnitude < float.Epsilon) return 0f;
            return (pointOnSegment - a).magnitude / (b - a).magnitude;
        }

        public Vector3 Evaluate(float t)
        {
            var ab = b - a;
            return a + ab * t;
        }

        public LocalSegment3 Transform(Matrix4x4 m, bool fullMultiply = false)
        {
            if (fullMultiply)
            {
                return new LocalSegment3(m.MultiplyPoint(a), m.MultiplyPoint(b));
            }
            else
            {
                return new LocalSegment3(m.MultiplyPoint3x4(a), m.MultiplyPoint3x4(b));
            }
        }

        #region Collision

        /// <summary>
        /// Returns the squared distance between this line segment and the rect.
        /// </summary>
        public float Intersect(Rect rect)
        {
            return Collision.Intersect(this, rect);
        }

        #endregion

        #region Runtime Gizmos

        public void DrawRuntimeGizmos(RuntimeGizmoDrawer drawer)
        {
            drawer.DrawLine(a, b);
        }

        #endregion

    }

}