// 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.
//
// Copyright (c) 2010-2013 SharpDX - Alexandre Mutel
//
// 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>
    /// A rectangle structure defining X,Y,Width,Height.
    /// </summary>
    [DataContract( Name = "Rectangle" )]
    [DataStyle( DataStyle.Compact )]
    [StructLayout( LayoutKind.Sequential, Pack = 4 )]
    public struct Rectangle : IEquatable<Rectangle>
    {
        /// <summary>
        /// An empty rectangle.
        /// </summary>
        public static readonly Rectangle Empty;

        static Rectangle()
        {
            Empty = new Rectangle();
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="Rectangle"/> struct.
        /// </summary>
        /// <param name="x">The left.</param>
        /// <param name="y">The top.</param>
        /// <param name="width">The width.</param>
        /// <param name="height">The height.</param>
        public Rectangle( int x, int y, int width, int height )
        {
            this.X = x;
            this.Y = y;
            this.Width = width;
            this.Height = height;
        }

        /// <summary>
        /// Gets or sets the left.
        /// </summary>
        /// <value>The left.</value>
        [DataMemberIgnore]
        public int Left
        {
            get { return X; }
            set { X = value; }
        }

        /// <summary>
        /// Gets or sets the top.
        /// </summary>
        /// <value>The top.</value>
        [DataMemberIgnore]
        public int Top
        {
            get { return Y; }
            set { Y = value; }
        }

        /// <summary>
        /// Gets or sets the right.
        /// </summary>
        /// <value>The right.</value>
        [DataMemberIgnore]
        public int Right
        {
            get { return X + Width; }
        }

        /// <summary>
        /// Gets or sets the bottom.
        /// </summary>
        /// <value>The bottom.</value>
        [DataMemberIgnore]
        public int Bottom
        {
            get { return Y + Height; }
        }

        /// <summary>
        /// Gets or sets the X position.
        /// </summary>
        /// <value>The X position.</value>
        [DataMember( Order = 0 )]
        public int X;

        /// <summary>
        /// Gets or sets the Y position.
        /// </summary>
        /// <value>The Y position.</value>
        [DataMember( Order = 1 )]
        public int Y;

        /// <summary>
        /// Gets or sets the width.
        /// </summary>
        /// <value>The width.</value>
        [DataMember( Order = 2 )]
        public int Width;

        /// <summary>
        /// Gets or sets the height.
        /// </summary>
        /// <value>The height.</value>
        [DataMember( Order = 3 )]
        public int Height;

        /// <summary>
        /// Gets or sets the location.
        /// </summary>
        /// <value>
        /// The location.
        /// </value>
        [DataMemberIgnore]
        public Point Location
        {
            get
            {
                return new Point( X, Y );
            }
            set
            {
                X = value.X;
                Y = value.Y;
            }
        }

        /// <summary>
        /// Gets the Point that specifies the center of the rectangle.
        /// </summary>
        /// <value>
        /// The center.
        /// </value>
        [DataMemberIgnore]
        public Point Center
        {
            get
            {
                return new Point( X + ( Width / 2 ), Y + ( Height / 2 ) );
            }
        }

        /// <summary>
        /// Gets a value that indicates whether the rectangle is empty.
        /// </summary>
        /// <value>
        ///   <c>true</c> if [is empty]; otherwise, <c>false</c>.
        /// </value>
        public bool IsEmpty
        {
            get
            {
                return ( Width == 0 ) && ( Height == 0 ) && ( X == 0 ) && ( Y == 0 );
            }
        }

        /// <summary>
        /// Gets or sets the size of the rectangle.
        /// </summary>
        /// <value>The size of the rectangle.</value>
        [DataMemberIgnore]
        public Size2 Size
        {
            get
            {
                return new Size2( Width, Height );
            }
            set
            {
                Width = value.Width;
                Height = value.Height;
            }
        }

        /// <summary>
        /// Gets the position of the top-left corner of the rectangle.
        /// </summary>
        /// <value>The top-left corner of the rectangle.</value>
        public Point TopLeft { get { return new Point( Left, Top ); } }

        /// <summary>
        /// Gets the position of the top-right corner of the rectangle.
        /// </summary>
        /// <value>The top-right corner of the rectangle.</value>
        public Point TopRight { get { return new Point( Right, Top ); } }

        /// <summary>
        /// Gets the position of the bottom-left corner of the rectangle.
        /// </summary>
        /// <value>The bottom-left corner of the rectangle.</value>
        public Point BottomLeft { get { return new Point( Left, Bottom ); } }

        /// <summary>
        /// Gets the position of the bottom-right corner of the rectangle.
        /// </summary>
        /// <value>The bottom-right corner of the rectangle.</value>
        public Point BottomRight { get { return new Point( Right, Bottom ); } }

        /// <summary>Changes the position of the rectangle.</summary>
        /// <param name="amount">The values to adjust the position of the rectangle by.</param>
        public void Offset( Point amount )
        {
            Offset( amount.X, amount.Y );
        }

        /// <summary>Changes the position of the rectangle.</summary>
        /// <param name="offsetX">Change in the x-position.</param>
        /// <param name="offsetY">Change in the y-position.</param>
        public void Offset( int offsetX, int offsetY )
        {
            X += offsetX;
            Y += offsetY;
        }

        /// <summary>Pushes the edges of the rectangle out by the horizontal and vertical values specified.</summary>
        /// <param name="horizontalAmount">Value to push the sides out by.</param>
        /// <param name="verticalAmount">Value to push the top and bottom out by.</param>
        public void Inflate( int horizontalAmount, int verticalAmount )
        {
            X -= horizontalAmount;
            Y -= verticalAmount;
            Width += horizontalAmount * 2;
            Height += verticalAmount * 2;
        }

        /// <summary>Determines whether this rectangle contains a specified point represented by its x- and y-coordinates.</summary>
        /// <param name="x">The x-coordinate of the specified point.</param>
        /// <param name="y">The y-coordinate of the specified point.</param>
        public bool Contains( int x, int y )
        {
            return ( X <= x ) && ( x < Right ) && ( Y <= y ) && ( y < Bottom );
        }

        /// <summary>Determines whether this rectangle contains a specified Point.</summary>
        /// <param name="value">The Point to evaluate.</param>
        public bool Contains( Point value )
        {
            bool result;
            Contains( ref value, out result );
            return result;
        }

        /// <summary>Determines whether this rectangle contains a specified Point.</summary>
        /// <param name="value">The Point to evaluate.</param>
        /// <param name="result">[OutAttribute] true if the specified Point is contained within this rectangle; false otherwise.</param>
        public void Contains( ref Point value, out bool result )
        {
            result = ( X <= value.X ) && ( value.X < Right ) && ( Y <= value.Y ) && ( value.Y < Bottom );
        }

        /// <summary>Determines whether this rectangle entirely contains a specified rectangle.</summary>
        /// <param name="value">The rectangle to evaluate.</param>
        public bool Contains( Rectangle value )
        {
            bool result;
            Contains( ref value, out result );
            return result;
        }

        /// <summary>Determines whether this rectangle entirely contains a specified rectangle.</summary>
        /// <param name="value">The rectangle to evaluate.</param>
        /// <param name="result">[OutAttribute] On exit, is true if this rectangle entirely contains the specified rectangle, or false if not.</param>
        public void Contains( ref Rectangle value, out bool result )
        {
            result = ( X <= value.X ) && ( value.Right <= Right ) && ( Y <= value.Y ) && ( value.Bottom <= Bottom );
        }

        /// <summary>
        /// Checks, if specified point is inside <see cref="Rectangle"/>.
        /// </summary>
        /// <param name="x">X point coordinate.</param>
        /// <param name="y">Y point coordinate.</param>
        /// <returns><c>true</c> if point is inside <see cref="Rectangle"/>, otherwise <c>false</c>.</returns>
        public bool Contains( float x, float y )
        {
            return ( x >= this.X && x <= Right && y >= this.Y && y <= Bottom );
        }

        /// <summary>
        /// Checks, if specified <see cref="Vec2"/> is inside <see cref="Rectangle"/>.
        /// </summary>
        /// <param name="vector2D">Coordinate <see cref="Vec2"/>.</param>
        /// <returns><c>true</c> if <see cref="Vec2"/> is inside <see cref="Rectangle"/>, otherwise <c>false</c>.</returns>
        public bool Contains( Vec2 vector2D )
        {
            return Contains( vector2D.X, vector2D.Y );
        }

        /// <summary>
        /// Checks, if specified <see cref="Int2"/> is inside <see cref="Rectangle"/>.
        /// </summary>
        /// <param name="int2">Coordinate <see cref="Int2"/>.</param>
        /// <returns><c>true</c> if <see cref="Int2"/> is inside <see cref="Rectangle"/>, otherwise <c>false</c>.</returns>
        public bool Contains( Int2 int2 )
        {
            return Contains( int2.X, int2.Y );
        }

        /// <summary>Determines whether a specified rectangle intersects with this rectangle.</summary>
        /// <param name="value">The rectangle to evaluate.</param>
        public bool Intersects( Rectangle value )
        {
            bool result;
            Intersects( ref value, out result );
            return result;
        }

        /// <summary>
        /// Determines whether a specified rectangle intersects with this rectangle.
        /// </summary>
        /// <param name="value">The rectangle to evaluate</param>
        /// <param name="result">[OutAttribute] true if the specified rectangle intersects with this one; false otherwise.</param>
        public void Intersects( ref Rectangle value, out bool result )
        {
            result = ( value.X < Right ) && ( X < value.Right ) && ( value.Y < Bottom ) && ( Y < value.Bottom );
        }

        /// <summary>
        /// Creates a rectangle defining the area where one rectangle overlaps with another rectangle.
        /// </summary>
        /// <param name="value1">The first rectangle to compare.</param>
        /// <param name="value2">The second rectangle to compare.</param>
        /// <returns>The intersection rectangle.</returns>
        public static Rectangle Intersect( Rectangle value1, Rectangle value2 )
        {
            Rectangle result;
            Intersect( ref value1, ref value2, out result );
            return result;
        }

        /// <summary>Creates a rectangle defining the area where one rectangle overlaps with another rectangle.</summary>
        /// <param name="value1">The first rectangle to compare.</param>
        /// <param name="value2">The second rectangle to compare.</param>
        /// <param name="result">[OutAttribute] The area where the two first parameters overlap.</param>
        public static void Intersect( ref Rectangle value1, ref Rectangle value2, out Rectangle result )
        {
            int newLeft = ( value1.X > value2.X ) ? value1.X : value2.X;
            int newTop = ( value1.Y > value2.Y ) ? value1.Y : value2.Y;
            int newRight = ( value1.Right < value2.Right ) ? value1.Right : value2.Right;
            int newBottom = ( value1.Bottom < value2.Bottom ) ? value1.Bottom : value2.Bottom;
            if( ( newRight > newLeft ) && ( newBottom > newTop ) )
            {
                result = new Rectangle( newLeft, newTop, newRight - newLeft, newBottom - newTop );
            }
            else
            {
                result = Empty;
            }
        }

        /// <summary>
        /// Creates a new rectangle that incorporate the provided point to the given rectangle.
        /// </summary>
        /// <param name="rectangle">The original rectangle.</param>
        /// <param name="point">The point to incorporate.</param>
        /// <returns>The union rectangle.</returns>
        public static Rectangle Union( Rectangle rectangle, Int2 point )
        {
            Rectangle result;
            var rect = new Rectangle( point.X, point.Y, 1, 1 );
            Union( ref rectangle, ref rect, out result );
            return result;
        }

        /// <summary>
        /// Creates a new rectangle that exactly contains two other rectangles.
        /// </summary>
        /// <param name="value1">The first rectangle to contain.</param>
        /// <param name="value2">The second rectangle to contain.</param>
        /// <returns>The union rectangle.</returns>
        public static Rectangle Union( Rectangle value1, Rectangle value2 )
        {
            Rectangle result;
            Union( ref value1, ref value2, out result );
            return result;
        }

        /// <summary>
        /// Creates a new rectangle that exactly contains two other rectangles.
        /// </summary>
        /// <param name="value1">The first rectangle to contain.</param>
        /// <param name="value2">The second rectangle to contain.</param>
        /// <param name="result">[OutAttribute] The rectangle that must be the union of the first two rectangles.</param>
        public static void Union( ref Rectangle value1, ref Rectangle value2, out Rectangle result )
        {
            var left = Math.Min( value1.Left, value2.Left );
            var right = Math.Max( value1.Right, value2.Right );
            var top = Math.Min( value1.Top, value2.Top );
            var bottom = Math.Max( value1.Bottom, value2.Bottom );
            result = new Rectangle( left, top, right - left, bottom - top );
        }

        /// <summary>
        /// Determines whether the specified <see cref="object"/> is equal to this instance.
        /// </summary>
        /// <param name="obj">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 obj )
        {
            if( ReferenceEquals( null, obj ) )
                return false;
            if( obj.GetType() != typeof( Rectangle ) )
                return false;
            return Equals( (Rectangle)obj );
        }

        /// <summary>
        /// Determines whether the specified <see cref="Rectangle"/> is equal to this instance.
        /// </summary>
        /// <param name="other">The <see cref="Rectangle"/> to compare with this instance.</param>
        /// <returns>
        /// <c>true</c> if the specified <see cref="Rectangle"/> is equal to this instance; otherwise, <c>false</c>.
        /// </returns>
        public bool Equals( Rectangle other )
        {
            return other.X == this.X && other.Y == this.Y && other.Width == Width && other.Height == Height;
        }

        /// <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()
        {
            unchecked
            {
                int result = X;
                result = ( result * 397 ) ^ Y;
                result = ( result * 397 ) ^ Width;
                result = ( result * 397 ) ^ Height;
                return result;
            }
        }

        /// <summary>
        /// Implements the operator ==.
        /// </summary>
        /// <param name="left">The left.</param>
        /// <param name="right">The right.</param>
        /// <returns>The result of the operator.</returns>
        public static bool operator ==( Rectangle left, Rectangle right )
        {
            return left.Equals( right );
        }

        /// <summary>
        /// Implements the operator !=.
        /// </summary>
        /// <param name="left">The left.</param>
        /// <param name="right">The right.</param>
        /// <returns>The result of the operator.</returns>
        public static bool operator !=( Rectangle left, Rectangle right )
        {
            return !( left == right );
        }

        /// <summary>
        /// Performs an implicit conversion to the <see cref="RectangleF"/> structure.
        /// </summary>
        /// <remarks>Performs direct converstion from int to float.</remarks>
        /// <param name="value">The source <see cref="Rectangle"/> value.</param>
        /// <returns>The converted structure.</returns>
        public static implicit operator RectangleF( Rectangle value )
        {
            return new RectangleF( value.X, value.Y, value.Width, value.Height );
        }

        /// <inheritdoc/>
        public override string ToString()
        {
            return string.Format( CultureInfo.CurrentCulture, "X:{0} Y:{1} Width:{2} Height:{3}", X, Y, Width, Height );
        }
    }
}