/******************************************************************************
 * 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.Drawing;
using UnityEngine;

namespace Leap.Unity.Geometry
{

    [System.Serializable]
    public struct Frustum
    {

        [SerializeField]
        private float _angle;
        public float angle
        {
            get { _angle = Mathf.Clamp(_angle, -179f, 179f); return _angle; }
            set { _angle = Mathf.Clamp(value, -179f, 179f); }
        }
        public float near;
        public float far;
        public Transform transform;

        public Frustum(float angle, float near = 0.10f, float far = 0.50f,
          Transform transform = null)
        {
            this._angle = angle; this.near = near; this.far = far;
            this.transform = transform;
        }

        public void Draw(Drawer drawer)
        {
            var forward = Vector3.forward;
            var alpha = 0.3f;
            var color = LeapColor.cerulean.WithAlpha(alpha);

            // Near surface.
            var nearVec = forward * near;
            var nearRad = Mathf.Tan(angle / 2f * Mathf.Deg2Rad) * near;
            var nearCircle = new Geometry.Circle(center: nearVec,
              direction: forward, radius: nearRad, transform: transform);
            nearCircle.Draw(drawer, color);

            // Far surface.
            var farVec = forward * far;
            var farRad = Mathf.Tan(angle / 2f * Mathf.Deg2Rad) * far;
            var farCircle = new Geometry.Circle(center: farVec,
              direction: forward, radius: farRad, transform: transform);
            farCircle.Draw(drawer, color);

            var nearCirclePoints = nearCircle.Points(7);
            var farCirclePoints = farCircle.Points(7);
            for (var i = 0; i < 7; i++)
            {
                nearCirclePoints.MoveNext();
                farCirclePoints.MoveNext();
                drawer.Line(nearCirclePoints.Current, farCirclePoints.Current);
            }

            for (var rMult = 0.8f; rMult > 0.1f; rMult -= 0.2f)
            {
                drawer.color = color.WithAlpha(rMult * rMult * alpha);
                nearCircle.radius = nearRad * rMult;
                nearCircle.Draw(drawer);
            }

            for (var rMult = 0.8f; rMult > 0.1f; rMult -= 0.2f)
            {
                drawer.color = color.WithAlpha(rMult * rMult * alpha);
                farCircle.radius = farRad * rMult;
                farCircle.Draw(drawer);
            }
        }

    }

}