using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using Svg.Transforms;

namespace Svg
{
    /// <summary>
    /// Represents an SVG rectangle that could also have rounded edges.
    /// </summary>
    [SvgElement("rect")]
    public class SvgRectangle : SvgVisualElement
    {
        private SvgUnit _cornerRadiusX;
        private SvgUnit _cornerRadiusY;
        private SvgUnit _height;
        private GraphicsPath _path;
        private SvgUnit _width;
        private SvgUnit _x;
        private SvgUnit _y;

        /// <summary>
        /// Initializes a new instance of the <see cref="SvgRectangle"/> class.
        /// </summary>
        public SvgRectangle()
        {
            _width = new SvgUnit(0.0f);
            _height = new SvgUnit(0.0f);
            _cornerRadiusX = new SvgUnit(0.0f);
            _cornerRadiusY = new SvgUnit(0.0f);
            _x = new SvgUnit(0.0f);
            _y = new SvgUnit(0.0f);
        }

        /// <summary>
        /// Gets an <see cref="SvgPoint"/> representing the top left point of the rectangle.
        /// </summary>
        public SvgPoint Location
        {
            get { return new SvgPoint(X, Y); }
        }

        /// <summary>
        /// Gets or sets the position where the left point of the rectangle should start.
        /// </summary>
        [SvgAttribute("x")]
        public SvgUnit X
        {
        	get { return _x; }
        	set
        	{
        		if(_x != value)
        		{
        			_x = value;
        			OnAttributeChanged(new AttributeEventArgs{ Attribute = "x", Value = value });
        			IsPathDirty = true;
        		}
        	}
        }

        /// <summary>
        /// Gets or sets the position where the top point of the rectangle should start.
        /// </summary>
        [SvgAttribute("y")]
        public SvgUnit Y
        {
        	get { return _y; }
        	set
        	{
        		if(_y != value)
        		{
        			_y = value;
        			OnAttributeChanged(new AttributeEventArgs{ Attribute = "y", Value = value });
        			IsPathDirty = true;
        		}
        	}
        }

        /// <summary>
        /// Gets or sets the width of the rectangle.
        /// </summary>
        [SvgAttribute("width")]
        public SvgUnit Width
        {
        	get { return _width; }
        	set
        	{
        		if(_width != value)
        		{
        			_width = value;
        			OnAttributeChanged(new AttributeEventArgs{ Attribute = "width", Value = value });
        			IsPathDirty = true;
        		}
        	}
        }

        /// <summary>
        /// Gets or sets the height of the rectangle.
        /// </summary>
        [SvgAttribute("height")]
        public SvgUnit Height
        {
        	get { return _height; }
        	set
        	{
        		if(_height != value)
        		{
        			_height = value;
        			OnAttributeChanged(new AttributeEventArgs{ Attribute = "height", Value = value });
        			IsPathDirty = true;
        		}
        	}
        }

        /// <summary>
        /// Gets or sets the X-radius of the rounded edges of this rectangle.
        /// </summary>
        [SvgAttribute("rx")]
        public SvgUnit CornerRadiusX
        {
            get
            {
                // If ry has been set and rx hasn't, use it's value
                if (_cornerRadiusX.Value == 0.0f && _cornerRadiusY.Value > 0.0f)
                    return _cornerRadiusY;

                return _cornerRadiusX;
            }
            set
            {
                _cornerRadiusX = value;
                IsPathDirty = true;
            }
        }

        /// <summary>
        /// Gets or sets the Y-radius of the rounded edges of this rectangle.
        /// </summary>
        [SvgAttribute("ry")]
        public SvgUnit CornerRadiusY
        {
            get
            {
                // If rx has been set and ry hasn't, use it's value
                if (_cornerRadiusY.Value == 0.0f && _cornerRadiusX.Value > 0.0f)
                    return _cornerRadiusX;

                return _cornerRadiusY;
            }
            set
            {
                _cornerRadiusY = value;
                IsPathDirty = true;
            }
        }

        /// <summary>
        /// Gets or sets a value to determine if anti-aliasing should occur when the element is being rendered.
        /// </summary>
        protected override bool RequiresSmoothRendering
        {
            get
            {
                if (base.RequiresSmoothRendering)
                    return (CornerRadiusX.Value > 0 || CornerRadiusY.Value > 0);
                else
                    return false;
            }
        }

        /// <summary>
        /// Gets the bounds of the element.
        /// </summary>
        /// <value>The bounds.</value>
        public override RectangleF Bounds
        {
            get { return Path(null).GetBounds(); }
        }

        /// <summary>
        /// Gets the <see cref="GraphicsPath"/> for this element.
        /// </summary>
        public override GraphicsPath Path(ISvgRenderer renderer)
        {
            if ((_path == null || IsPathDirty) && base.StrokeWidth > 0)
            {
                var halfStrokeWidth = new SvgUnit(base.StrokeWidth / 2);

                // If it is to render, don't need to consider stroke
                if (renderer != null)
                {
                  halfStrokeWidth = 0;
                  this.IsPathDirty = false;
                }

                // If the corners aren't to be rounded just create a rectangle
                if (CornerRadiusX.Value == 0.0f && CornerRadiusY.Value == 0.0f)
                {
                  // Starting location which take consideration of stroke width
                  SvgPoint strokedLocation = new SvgPoint(Location.X - halfStrokeWidth, Location.Y - halfStrokeWidth);

                  var width = this.Width.ToDeviceValue(renderer, UnitRenderingType.Horizontal, this) + halfStrokeWidth;
                  var height = this.Height.ToDeviceValue(renderer, UnitRenderingType.Vertical, this) + halfStrokeWidth;
                  
                  var rectangle = new RectangleF(strokedLocation.ToDeviceValue(renderer, this), new SizeF(width, height));

                    _path = new GraphicsPath();
                    _path.StartFigure();
                    _path.AddRectangle(rectangle);
                    _path.CloseFigure();
                }
                else
                {
                    _path = new GraphicsPath();
                    var arcBounds = new RectangleF();
                    var lineStart = new PointF();
                    var lineEnd = new PointF();
                    var width = Width.ToDeviceValue(renderer, UnitRenderingType.Horizontal, this);
                    var height = Height.ToDeviceValue(renderer, UnitRenderingType.Vertical, this);
                    var rx = Math.Min(CornerRadiusX.ToDeviceValue(renderer, UnitRenderingType.Horizontal, this) * 2, width);
                    var ry = Math.Min(CornerRadiusY.ToDeviceValue(renderer, UnitRenderingType.Vertical, this) * 2, height);
                    var location = Location.ToDeviceValue(renderer, this);

                    // Start
                    _path.StartFigure();

                    // Add first arc
                    arcBounds.Location = location;
                    arcBounds.Width = rx;
                    arcBounds.Height = ry;
                    _path.AddArc(arcBounds, 180, 90);

                    // Add first line
                    lineStart.X = Math.Min(location.X + rx, location.X + width * 0.5f);
                    lineStart.Y = location.Y;
                    lineEnd.X = Math.Max(location.X + width - rx, location.X + width * 0.5f);
                    lineEnd.Y = lineStart.Y;
                    _path.AddLine(lineStart, lineEnd);

                    // Add second arc
                    arcBounds.Location = new PointF(location.X + width - rx, location.Y);
                    _path.AddArc(arcBounds, 270, 90);

                    // Add second line
                    lineStart.X = location.X + width;
                    lineStart.Y = Math.Min(location.Y + ry, location.Y + height * 0.5f);
                    lineEnd.X = lineStart.X;
                    lineEnd.Y = Math.Max(location.Y + height - ry, location.Y + height * 0.5f);
                    _path.AddLine(lineStart, lineEnd);

                    // Add third arc
                    arcBounds.Location = new PointF(location.X + width - rx, location.Y + height - ry);
                    _path.AddArc(arcBounds, 0, 90);

                    // Add third line
                    lineStart.X = Math.Max(location.X + width - rx, location.X + width * 0.5f);
                    lineStart.Y = location.Y + height;
                    lineEnd.X = Math.Min(location.X + rx, location.X + width * 0.5f);
                    lineEnd.Y = lineStart.Y;
                    _path.AddLine(lineStart, lineEnd);

                    // Add third arc
                    arcBounds.Location = new PointF(location.X, location.Y + height - ry);
                    _path.AddArc(arcBounds, 90, 90);

                    // Add fourth line
                    lineStart.X = location.X;
                    lineStart.Y = Math.Max(location.Y + height - ry, location.Y + height * 0.5f);
                    lineEnd.X = lineStart.X;
                    lineEnd.Y = Math.Min(location.Y + ry, location.Y + height * 0.5f);
                    _path.AddLine(lineStart, lineEnd);

                    // Close
                    _path.CloseFigure();
                }
            }
            return _path;
        }

        /// <summary>
        /// Renders the <see cref="SvgElement"/> and contents to the specified <see cref="Graphics"/> object.
        /// </summary>
        protected override void Render(ISvgRenderer renderer)
        {
            if (Width.Value > 0.0f && Height.Value > 0.0f)
            {
                base.Render(renderer);
            }
        }


		public override SvgElement DeepCopy()
		{
			return DeepCopy<SvgRectangle>();
		}

		public override SvgElement DeepCopy<T>()
		{
 			var newObj = base.DeepCopy<T>() as SvgRectangle;
			newObj.CornerRadiusX = this.CornerRadiusX;
			newObj.CornerRadiusY = this.CornerRadiusY;
			newObj.Height = this.Height;
			newObj.Width = this.Width;
			newObj.X = this.X;
			newObj.Y = this.Y;
			return newObj;
		}
    }
}