using System;

namespace RGB.NET.Core
{
    public static class RectangleExtensions
    {
        #region Methods

        /// <summary>
        /// Sets the <see cref="Rectangle.Location"/> of the given rectangle.
        /// </summary>
        /// <param name="rect">The rectangle to modify.</param>
        /// <param name="location">The new location of the rectangle.</param>
        /// <returns>The modified <see cref="Rectangle"/>.</returns>
        public static Rectangle SetLocation(this Rectangle rect, Point location) => new Rectangle(location, rect.Size);

        /// <summary>
        /// Sets the <see cref="Point.X"/> of the <see cref="Rectangle.Location"/> of the given rectangle.
        /// </summary>
        /// <param name="rect">The rectangle to modify.</param>
        /// <param name="x">The new x-location of the rectangle.</param>
        /// <returns>The modified <see cref="Rectangle"/>.</returns>
        public static Rectangle SetX(this Rectangle rect, double x) => new Rectangle(new Point(x, rect.Location.Y), rect.Size);

        /// <summary>
        /// Sets the <see cref="Point.Y"/> of the <see cref="Rectangle.Location"/> of the given rectangle.
        /// </summary>
        /// <param name="rect">The rectangle to modify.</param>
        /// <param name="y">The new y-location of the rectangle.</param>
        /// <returns>The modified <see cref="Rectangle"/>.</returns>
        public static Rectangle SetY(this Rectangle rect, double y) => new Rectangle(new Point(rect.Location.X, y), rect.Size);

        /// <summary>
        /// Sets the <see cref="Rectangle.Size"/> of the given rectangle.
        /// </summary>
        /// <param name="rect">The rectangle to modify.</param>
        /// <param name="size">The new size of the rectangle.</param>
        /// <returns>The modified <see cref="Rectangle"/>.</returns>
        public static Rectangle SetSize(this Rectangle rect, Size size) => new Rectangle(rect.Location, size);

        /// <summary>
        /// Sets the <see cref="Size.Width"/> of the <see cref="Rectangle.Size"/> of the given rectangle.
        /// </summary>
        /// <param name="rect">The rectangle to modify.</param>
        /// <param name="width">The new width of the rectangle.</param>
        /// <returns>The modified <see cref="Rectangle"/>.</returns>
        public static Rectangle SetWidth(this Rectangle rect, double width) => new Rectangle(rect.Location, new Size(width, rect.Size.Height));

        /// <summary>
        /// Sets the <see cref="Size.Height"/> of the <see cref="Rectangle.Size"/> of the given rectangle.
        /// </summary>
        /// <param name="rect">The rectangle to modify.</param>
        /// <param name="height">The new height of the rectangle.</param>
        /// <returns>The modified <see cref="Rectangle"/>.</returns>
        public static Rectangle SetHeight(this Rectangle rect, double height) => new Rectangle(rect.Location, new Size(rect.Size.Width, height));

        /// <summary>
        /// Calculates the percentage of intersection of a rectangle.
        /// </summary>
        /// <param name="intersectingRect">The intersecting rectangle.</param>
        /// <returns>The percentage of intersection.</returns>
        public static double CalculateIntersectPercentage(this Rectangle rect, Rectangle intersectingRect)
        {
            if (rect.IsEmpty || intersectingRect.IsEmpty) return 0;

            Rectangle intersection = rect.CalculateIntersection(intersectingRect);
            return (intersection.Size.Width * intersection.Size.Height) / (rect.Size.Width * rect.Size.Height);
        }

        /// <summary>
        /// Calculates the <see cref="Rectangle"/> representing the intersection of this <see cref="Rectangle"/> and the one provided as parameter.
        /// </summary>
        /// <param name="intersectingRectangle">The intersecting <see cref="Rectangle"/></param>
        /// <returns>A new <see cref="Rectangle"/> representing the intersection this <see cref="Rectangle"/> and the one provided as parameter.</returns>
        public static Rectangle CalculateIntersection(this Rectangle rect, Rectangle intersectingRectangle)
        {
            double x1 = Math.Max(rect.Location.X, intersectingRectangle.Location.X);
            double x2 = Math.Min(rect.Location.X + rect.Size.Width, intersectingRectangle.Location.X + intersectingRectangle.Size.Width);

            double y1 = Math.Max(rect.Location.Y, intersectingRectangle.Location.Y);
            double y2 = Math.Min(rect.Location.Y + rect.Size.Height, intersectingRectangle.Location.Y + intersectingRectangle.Size.Height);

            if ((x2 >= x1) && (y2 >= y1))
                return new Rectangle(x1, y1, x2 - x1, y2 - y1);

            return new Rectangle();
        }

        /// <summary>
        /// Determines if the specified <see cref="Point"/> is contained within this <see cref="Rectangle"/>.
        /// </summary>
        /// <param name="point">The <see cref="Point"/> to test.</param>
        /// <returns></returns>
        public static bool Contains(this Rectangle rect, Point point) => rect.Contains(point.X, point.Y);

        /// <summary>
        /// Determines if the specified location is contained within this <see cref="Rectangle"/>.
        /// </summary>
        /// <param name="x">The X-location to test.</param>
        /// <param name="y">The Y-location to test.</param>
        /// <returns></returns>
        public static bool Contains(this Rectangle rect, double x, double y) => (rect.Location.X <= x) && (x < (rect.Location.X + rect.Size.Width))
                                                                                && (rect.Location.Y <= y) && (y < (rect.Location.Y + rect.Size.Height));

        /// <summary>
        /// Determines if the specified <see cref="Rectangle"/> is contained within this <see cref="Rectangle"/>.
        /// </summary>
        /// <param name="rect">The <see cref="Rectangle"/> to test.</param>
        /// <returns></returns>
        public static bool Contains(this Rectangle rect, Rectangle rect2) => (rect.Location.X <= rect2.Location.X) && ((rect2.Location.X + rect2.Size.Width) <= (rect.Location.X + rect.Size.Width))
                                                                            && (rect.Location.Y <= rect2.Location.Y) && ((rect2.Location.Y + rect2.Size.Height) <= (rect.Location.Y + rect.Size.Height));

        #endregion
    }
}