// Copyright (c) Xenko contributors (https://xenko.com) and Silicon Studio Corp. (https://www.siliconstudio.co.jp)
// Distributed under the MIT license. See the LICENSE.md file in the project root for more information.
//
// -----------------------------------------------------------------------------
// Original code from SlimMath project. http://code.google.com/p/slimmath/
// Greetings to SlimDX Group. Original code published with the following license:
// -----------------------------------------------------------------------------
/*
* Copyright (c) 2007-2011 SlimDX Group
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
using System;
using System.Globalization;
using System.Runtime.InteropServices;
using System.Runtime.Serialization;

namespace math
{
    /// <summary>
    /// Represents an axis-aligned bounding box in three dimensional space.
    /// </summary>
    [DataContract]
    [StructLayout( LayoutKind.Sequential, Pack = 4 )]
    public struct BoundingBox : IEquatable<BoundingBox>, IFormattable
    {
        /// <summary>
        /// A <see cref="BoundingBox"/> which represents an empty space.
        /// </summary>
        public static readonly BoundingBox Empty = new BoundingBox( new Vec3( float.MaxValue ), new Vec3( float.MinValue ) );

        /// <summary>
        /// The minimum point of the box.
        /// </summary>
        public Vec3 Minimum;

        /// <summary>
        /// The maximum point of the box.
        /// </summary>
        public Vec3 Maximum;

        /// <summary>
        /// Initializes a new instance of the <see cref="math.BoundingBox"/> struct.
        /// </summary>
        /// <param name="minimum">The minimum vertex of the bounding box.</param>
        /// <param name="maximum">The maximum vertex of the bounding box.</param>
        public BoundingBox( Vec3 minimum, Vec3 maximum )
        {
            this.Minimum = minimum;
            this.Maximum = maximum;
        }

        /// <summary>
        /// Gets the center of this bouding box.
        /// </summary>
        public Vec3 Center
        {
            get { return ( Minimum + Maximum ) / 2; }
        }

        /// <summary>
        /// Gets the extent of this bouding box.
        /// </summary>
        public Vec3 Extent
        {
            get { return ( Maximum - Minimum ) / 2; }
        }

        /// <summary>
        /// Retrieves the eight corners of the bounding box.
        /// </summary>
        /// <returns>An array of points representing the eight corners of the bounding box.</returns>
        public Vec3[] GetCorners()
        {
            Vec3[] results = new Vec3[8];
            results[0] = new Vec3( Minimum.X, Maximum.Y, Maximum.Z );
            results[1] = new Vec3( Maximum.X, Maximum.Y, Maximum.Z );
            results[2] = new Vec3( Maximum.X, Minimum.Y, Maximum.Z );
            results[3] = new Vec3( Minimum.X, Minimum.Y, Maximum.Z );
            results[4] = new Vec3( Minimum.X, Maximum.Y, Minimum.Z );
            results[5] = new Vec3( Maximum.X, Maximum.Y, Minimum.Z );
            results[6] = new Vec3( Maximum.X, Minimum.Y, Minimum.Z );
            results[7] = new Vec3( Minimum.X, Minimum.Y, Minimum.Z );
            return results;
        }

        /// <summary>
        /// Determines if there is an intersection between the current object and a <see cref="math.Ray"/>.
        /// </summary>
        /// <param name="ray">The ray to test.</param>
        /// <returns>Whether the two objects intersected.</returns>
        public bool Intersects( ref Ray ray )
        {
            float distance;
            return CollisionHelper.RayIntersectsBox( ref ray, ref this, out distance );
        }

        /// <summary>
        /// Determines if there is an intersection between the current object and a <see cref="math.Ray"/>.
        /// </summary>
        /// <param name="ray">The ray to test.</param>
        /// <param name="distance">When the method completes, contains the distance of the intersection,
        /// or 0 if there was no intersection.</param>
        /// <returns>Whether the two objects intersected.</returns>
        public bool Intersects( ref Ray ray, out float distance )
        {
            return CollisionHelper.RayIntersectsBox( ref ray, ref this, out distance );
        }

        /// <summary>
        /// Determines if there is an intersection between the current object and a <see cref="math.Ray"/>.
        /// </summary>
        /// <param name="ray">The ray to test.</param>
        /// <param name="point">When the method completes, contains the point of intersection,
        /// or <see cref="math.Vec3.Zero"/> if there was no intersection.</param>
        /// <returns>Whether the two objects intersected.</returns>
        public bool Intersects( ref Ray ray, out Vec3 point )
        {
            return CollisionHelper.RayIntersectsBox( ref ray, ref this, out point );
        }

        /// <summary>
        /// Determines if there is an intersection between the current object and a <see cref="math.Plane"/>.
        /// </summary>
        /// <param name="plane">The plane to test.</param>
        /// <returns>Whether the two objects intersected.</returns>
        public PlaneIntersectionType Intersects( ref Plane plane )
        {
            return CollisionHelper.PlaneIntersectsBox( ref plane, ref this );
        }

        /* This implentation is wrong
        /// <summary>
        /// Determines if there is an intersection between the current object and a triangle.
        /// </summary>
        /// <param name="vertex1">The first vertex of the triangle to test.</param>
        /// <param name="vertex2">The second vertex of the triagnle to test.</param>
        /// <param name="vertex3">The third vertex of the triangle to test.</param>
        /// <returns>Whether the two objects intersected.</returns>
        public bool Intersects(ref Vector3 vertex1, ref Vector3 vertex2, ref Vector3 vertex3)
        {
            return Collision.BoxIntersectsTriangle(ref this, ref vertex1, ref vertex2, ref vertex3);
        }
        */

        /// <summary>
        /// Determines if there is an intersection between the current object and a <see cref="math.BoundingBox"/>.
        /// </summary>
        /// <param name="box">The box to test.</param>
        /// <returns>Whether the two objects intersected.</returns>
        public bool Intersects( ref BoundingBox box )
        {
            return CollisionHelper.BoxIntersectsBox( ref this, ref box );
        }

        /// <summary>
        /// Determines if there is an intersection between the current object and a <see cref="math.BoundingSphere"/>.
        /// </summary>
        /// <param name="sphere">The sphere to test.</param>
        /// <returns>Whether the two objects intersected.</returns>
        public bool Intersects( ref BoundingSphere sphere )
        {
            return CollisionHelper.BoxIntersectsSphere( ref this, ref sphere );
        }

        /// <summary>
        /// Determines whether the current objects contains a point.
        /// </summary>
        /// <param name="point">The point to test.</param>
        /// <returns>The type of containment the two objects have.</returns>
        public ContainmentType Contains( ref Vec3 point )
        {
            return CollisionHelper.BoxContainsPoint( ref this, ref point );
        }

        /* This implentation is wrong
        /// <summary>
        /// Determines whether the current objects contains a triangle.
        /// </summary>
        /// <param name="vertex1">The first vertex of the triangle to test.</param>
        /// <param name="vertex2">The second vertex of the triagnle to test.</param>
        /// <param name="vertex3">The third vertex of the triangle to test.</param>
        /// <returns>The type of containment the two objects have.</returns>
        public ContainmentType Contains(ref Vector3 vertex1, ref Vector3 vertex2, ref Vector3 vertex3)
        {
            return Collision.BoxContainsTriangle(ref this, ref vertex1, ref vertex2, ref vertex3);
        }
        */

        /// <summary>
        /// Determines whether the current objects contains a <see cref="math.BoundingBox"/>.
        /// </summary>
        /// <param name="box">The box to test.</param>
        /// <returns>The type of containment the two objects have.</returns>
        public ContainmentType Contains( ref BoundingBox box )
        {
            return CollisionHelper.BoxContainsBox( ref this, ref box );
        }

        /// <summary>
        /// Determines whether the current objects contains a <see cref="math.BoundingSphere"/>.
        /// </summary>
        /// <param name="sphere">The sphere to test.</param>
        /// <returns>The type of containment the two objects have.</returns>
        public ContainmentType Contains( ref BoundingSphere sphere )
        {
            return CollisionHelper.BoxContainsSphere( ref this, ref sphere );
        }

        /// <summary>
        /// Constructs a <see cref="math.BoundingBox"/> that fully contains the given points.
        /// </summary>
        /// <param name="points">The points that will be contained by the box.</param>
        /// <param name="result">When the method completes, contains the newly constructed bounding box.</param>
        /// <exception cref="ArgumentNullException">Thrown when <paramref name="points"/> is <c>null</c>.</exception>
        public static void FromPoints( Vec3[] points, out BoundingBox result )
        {
            if( points == null )
                throw new ArgumentNullException( "points" );

            Vec3 min = new Vec3( float.MaxValue );
            Vec3 max = new Vec3( float.MinValue );

            for( int i = 0; i < points.Length; ++i )
            {
                Vec3.Min( ref min, ref points[i], out min );
                Vec3.Max( ref max, ref points[i], out max );
            }

            result = new BoundingBox( min, max );
        }

        /// <summary>
        /// Constructs a <see cref="math.BoundingBox"/> that fully contains the given points.
        /// </summary>
        /// <param name="points">The points that will be contained by the box.</param>
        /// <returns>The newly constructed bounding box.</returns>
        /// <exception cref="ArgumentNullException">Thrown when <paramref name="points"/> is <c>null</c>.</exception>
        public static BoundingBox FromPoints( Vec3[] points )
        {
            if( points == null )
                throw new ArgumentNullException( "points" );

            Vec3 min = new Vec3( float.MaxValue );
            Vec3 max = new Vec3( float.MinValue );

            for( int i = 0; i < points.Length; ++i )
            {
                Vec3.Min( ref min, ref points[i], out min );
                Vec3.Max( ref max, ref points[i], out max );
            }

            return new BoundingBox( min, max );
        }

        /// <summary>
        /// Constructs a <see cref="math.BoundingBox"/> from a given sphere.
        /// </summary>
        /// <param name="sphere">The sphere that will designate the extents of the box.</param>
        /// <param name="result">When the method completes, contains the newly constructed bounding box.</param>
        public static void FromSphere( ref BoundingSphere sphere, out BoundingBox result )
        {
            result.Minimum = new Vec3( sphere.Center.X - sphere.Radius, sphere.Center.Y - sphere.Radius, sphere.Center.Z - sphere.Radius );
            result.Maximum = new Vec3( sphere.Center.X + sphere.Radius, sphere.Center.Y + sphere.Radius, sphere.Center.Z + sphere.Radius );
        }

        /// <summary>
        /// Constructs a <see cref="math.BoundingBox"/> from a given sphere.
        /// </summary>
        /// <param name="sphere">The sphere that will designate the extents of the box.</param>
        /// <returns>The newly constructed bounding box.</returns>
        public static BoundingBox FromSphere( BoundingSphere sphere )
        {
            BoundingBox box;
            box.Minimum = new Vec3( sphere.Center.X - sphere.Radius, sphere.Center.Y - sphere.Radius, sphere.Center.Z - sphere.Radius );
            box.Maximum = new Vec3( sphere.Center.X + sphere.Radius, sphere.Center.Y + sphere.Radius, sphere.Center.Z + sphere.Radius );
            return box;
        }

        /// <summary>
        /// Transform a bounding box.
        /// </summary>
        /// <param name="value">The original bounding box.</param>
        /// <param name="transform">The transform to apply to the bounding box.</param>
        /// <param name="result">The transformed bounding box.</param>
        public static void Transform( ref BoundingBox value, ref Matrix transform, out BoundingBox result )
        {
            var boundingBox = new BoundingBoxExt( value );
            boundingBox.Transform( transform );
            result = (BoundingBox)boundingBox;
        }

        /// <summary>
        /// Constructs a <see cref="math.BoundingBox"/> that is as large enough to contains the bounding box and the given point.
        /// </summary>
        /// <param name="value1">The box to merge.</param>
        /// <param name="value2">The point to merge.</param>
        /// <param name="result">When the method completes, contains the newly constructed bounding box.</param>
        public static void Merge( ref BoundingBox value1, ref Vec3 value2, out BoundingBox result )
        {
            Vec3.Min( ref value1.Minimum, ref value2, out result.Minimum );
            Vec3.Max( ref value1.Maximum, ref value2, out result.Maximum );
        }

        /// <summary>
        /// Constructs a <see cref="math.BoundingBox"/> that is as large as the total combined area of the two specified boxes.
        /// </summary>
        /// <param name="value1">The first box to merge.</param>
        /// <param name="value2">The second box to merge.</param>
        /// <param name="result">When the method completes, contains the newly constructed bounding box.</param>
        public static void Merge( ref BoundingBox value1, ref BoundingBox value2, out BoundingBox result )
        {
            Vec3.Min( ref value1.Minimum, ref value2.Minimum, out result.Minimum );
            Vec3.Max( ref value1.Maximum, ref value2.Maximum, out result.Maximum );
        }

        /// <summary>
        /// Constructs a <see cref="math.BoundingBox"/> that is as large as the total combined area of the two specified boxes.
        /// </summary>
        /// <param name="value1">The first box to merge.</param>
        /// <param name="value2">The second box to merge.</param>
        /// <returns>The newly constructed bounding box.</returns>
        public static BoundingBox Merge( BoundingBox value1, BoundingBox value2 )
        {
            BoundingBox box;
            Vec3.Min( ref value1.Minimum, ref value2.Minimum, out box.Minimum );
            Vec3.Max( ref value1.Maximum, ref value2.Maximum, out box.Maximum );
            return box;
        }

        /// <summary>
        /// Tests for equality between two objects.
        /// </summary>
        /// <param name="left">The first value to compare.</param>
        /// <param name="right">The second value to compare.</param>
        /// <returns><c>true</c> if <paramref name="left"/> has the same value as <paramref name="right"/>; otherwise, <c>false</c>.</returns>
        public static bool operator ==( BoundingBox left, BoundingBox right )
        {
            return left.Equals( right );
        }

        /// <summary>
        /// Tests for inequality between two objects.
        /// </summary>
        /// <param name="left">The first value to compare.</param>
        /// <param name="right">The second value to compare.</param>
        /// <returns><c>true</c> if <paramref name="left"/> has a different value than <paramref name="right"/>; otherwise, <c>false</c>.</returns>
        public static bool operator !=( BoundingBox left, BoundingBox right )
        {
            return !left.Equals( right );
        }

        /// <summary>
        /// Returns a <see cref="string"/> that represents this instance.
        /// </summary>
        /// <returns>
        /// A <see cref="string"/> that represents this instance.
        /// </returns>
        public override string ToString()
        {
            return string.Format( CultureInfo.CurrentCulture, "Minimum:{0} Maximum:{1}", Minimum.ToString(), Maximum.ToString() );
        }

        /// <summary>
        /// Returns a <see cref="string"/> that represents this instance.
        /// </summary>
        /// <param name="format">The format.</param>
        /// <returns>
        /// A <see cref="string"/> that represents this instance.
        /// </returns>
        public string ToString( string format )
        {
            if( format == null )
                return ToString();

            return string.Format( CultureInfo.CurrentCulture, "Minimum:{0} Maximum:{1}", Minimum.ToString( format, CultureInfo.CurrentCulture ),
                Maximum.ToString( format, CultureInfo.CurrentCulture ) );
        }

        /// <summary>
        /// Returns a <see cref="string"/> that represents this instance.
        /// </summary>
        /// <param name="formatProvider">The format provider.</param>
        /// <returns>
        /// A <see cref="string"/> that represents this instance.
        /// </returns>
        public string ToString( IFormatProvider formatProvider )
        {
            return string.Format( formatProvider, "Minimum:{0} Maximum:{1}", Minimum.ToString(), Maximum.ToString() );
        }

        /// <summary>
        /// Returns a <see cref="string"/> that represents this instance.
        /// </summary>
        /// <param name="format">The format.</param>
        /// <param name="formatProvider">The format provider.</param>
        /// <returns>
        /// A <see cref="string"/> that represents this instance.
        /// </returns>
        public string ToString( string format, IFormatProvider formatProvider )
        {
            if( format == null )
                return ToString( formatProvider );

            return string.Format( formatProvider, "Minimum:{0} Maximum:{1}", Minimum.ToString( format, formatProvider ),
                Maximum.ToString( format, formatProvider ) );
        }

        /// <summary>
        /// Returns a hash code for this instance.
        /// </summary>
        /// <returns>
        /// A hash code for this instance, suitable for use in hashing algorithms and data structures like a hash table.
        /// </returns>
        public override int GetHashCode()
        {
            return Minimum.GetHashCode() + Maximum.GetHashCode();
        }

        /// <summary>
        /// Determines whether the specified <see cref="math.Vec4"/> is equal to this instance.
        /// </summary>
        /// <param name="value">The <see cref="math.Vec4"/> to compare with this instance.</param>
        /// <returns>
        /// <c>true</c> if the specified <see cref="math.Vec4"/> is equal to this instance; otherwise, <c>false</c>.
        /// </returns>
        public bool Equals( BoundingBox value )
        {
            return Minimum == value.Minimum && Maximum == value.Maximum;
        }

        /// <summary>
        /// Determines whether the specified <see cref="object"/> is equal to this instance.
        /// </summary>
        /// <param name="value">The <see cref="object"/> to compare with this instance.</param>
        /// <returns>
        /// <c>true</c> if the specified <see cref="object"/> is equal to this instance; otherwise, <c>false</c>.
        /// </returns>
        public override bool Equals( object value )
        {
            if( value == null )
                return false;

            if( value.GetType() != GetType() )
                return false;

            return Equals( (BoundingBox)value );
        }
    }
}