// 
// Rectangle.cs
//  
// Author:
//       Lluis Sanchez <lluis@xamarin.com>
// 
// Copyright (c) 2011 Xamarin Inc
// 
// 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.Diagnostics;
using System.Globalization;

namespace Xamarin.Forms
{
	[DebuggerDisplay("X={X}, Y={Y}, Width={Width}, Height={Height}")]
	[TypeConverter(typeof(RectangleTypeConverter))]
	public struct Rectangle
	{
		public double X { get; set; }

		public double Y { get; set; }

		public double Width { get; set; }

		public double Height { get; set; }

		public static Rectangle Zero = new Rectangle();

		public override string ToString()
		{
			return string.Format("{{X={0} Y={1} Width={2} Height={3}}}", X.ToString(CultureInfo.InvariantCulture), Y.ToString(CultureInfo.InvariantCulture), Width.ToString(CultureInfo.InvariantCulture),
				Height.ToString(CultureInfo.InvariantCulture));
		}

		// constructors
		public Rectangle(double x, double y, double width, double height) : this()
		{
			X = x;
			Y = y;
			Width = width;
			Height = height;
		}

		public Rectangle(Point loc, Size sz) : this(loc.X, loc.Y, sz.Width, sz.Height)
		{
		}

		public static Rectangle FromLTRB(double left, double top, double right, double bottom)
		{
			return new Rectangle(left, top, right - left, bottom - top);
		}

		public bool Equals(Rectangle other)
		{
			return X.Equals(other.X) && Y.Equals(other.Y) && Width.Equals(other.Width) && Height.Equals(other.Height);
		}

		public override bool Equals(object obj)
		{
			if (ReferenceEquals(null, obj))
				return false;
			return obj is Rectangle && Equals((Rectangle)obj);
		}

		public override int GetHashCode()
		{
			unchecked
			{
				int hashCode = X.GetHashCode();
				hashCode = (hashCode * 397) ^ Y.GetHashCode();
				hashCode = (hashCode * 397) ^ Width.GetHashCode();
				hashCode = (hashCode * 397) ^ Height.GetHashCode();
				return hashCode;
			}
		}

		public static bool operator ==(Rectangle r1, Rectangle r2)
		{
			return (r1.Location == r2.Location) && (r1.Size == r2.Size);
		}

		public static bool operator !=(Rectangle r1, Rectangle r2)
		{
			return !(r1 == r2);
		}

		// Hit Testing / Intersection / Union
		public bool Contains(Rectangle rect)
		{
			return X <= rect.X && Right >= rect.Right && Y <= rect.Y && Bottom >= rect.Bottom;
		}

		public bool Contains(Point pt)
		{
			return Contains(pt.X, pt.Y);
		}

		public bool Contains(double x, double y)
		{
			return (x >= Left) && (x < Right) && (y >= Top) && (y < Bottom);
		}

		public bool IntersectsWith(Rectangle r)
		{
			return !((Left >= r.Right) || (Right <= r.Left) || (Top >= r.Bottom) || (Bottom <= r.Top));
		}

		public Rectangle Union(Rectangle r)
		{
			return Union(this, r);
		}

		public static Rectangle Union(Rectangle r1, Rectangle r2)
		{
			return FromLTRB(Math.Min(r1.Left, r2.Left), Math.Min(r1.Top, r2.Top), Math.Max(r1.Right, r2.Right), Math.Max(r1.Bottom, r2.Bottom));
		}

		public Rectangle Intersect(Rectangle r)
		{
			return Intersect(this, r);
		}

		public static Rectangle Intersect(Rectangle r1, Rectangle r2)
		{
			double x = Math.Max(r1.X, r2.X);
			double y = Math.Max(r1.Y, r2.Y);
			double width = Math.Min(r1.Right, r2.Right) - x;
			double height = Math.Min(r1.Bottom, r2.Bottom) - y;

			if (width < 0 || height < 0)
			{
				return Zero;
			}
			return new Rectangle(x, y, width, height);
		}

		// Position/Size
		public double Top
		{
			get { return Y; }
			set { Y = value; }
		}

		public double Bottom
		{
			get { return Y + Height; }
			set { Height = value - Y; }
		}

		public double Right
		{
			get { return X + Width; }
			set { Width = value - X; }
		}

		public double Left
		{
			get { return X; }
			set { X = value; }
		}

		public bool IsEmpty
		{
			get { return (Width <= 0) || (Height <= 0); }
		}

		public Size Size
		{
			get { return new Size(Width, Height); }
			set
			{
				Width = value.Width;
				Height = value.Height;
			}
		}

		public Point Location
		{
			get { return new Point(X, Y); }
			set
			{
				X = value.X;
				Y = value.Y;
			}
		}

		public Point Center
		{
			get { return new Point(X + Width / 2, Y + Height / 2); }
		}

		// Inflate and Offset
		public Rectangle Inflate(Size sz)
		{
			return Inflate(sz.Width, sz.Height);
		}

		public Rectangle Inflate(double width, double height)
		{
			Rectangle r = this;
			r.X -= width;
			r.Y -= height;
			r.Width += width * 2;
			r.Height += height * 2;
			return r;
		}

		public Rectangle Offset(double dx, double dy)
		{
			Rectangle r = this;
			r.X += dx;
			r.Y += dy;
			return r;
		}

		public Rectangle Offset(Point dr)
		{
			return Offset(dr.X, dr.Y);
		}

		public Rectangle Round()
		{
			return new Rectangle(Math.Round(X), Math.Round(Y), Math.Round(Width), Math.Round(Height));
		}
	}
}