using Microsoft.Xna.Framework.Graphics;

namespace SplitScreenSunBurn
{
	/// <summary>
	/// Represents the many standard viewports.
	/// </summary>
	public enum ViewportLocation
	{
		FullScreen,
		TopHalf,
		BottomHalf,
		LeftHalf,
		RightHalf,
		TopLeftQuarter,
		TopRightQuarter,
		BottomLeftQuarter,
		BottomRightQuarter
	}

	public static class GraphicsDeviceExtensions
	{
		/// <summary>
		/// Sets the viewport on the GraphicsDevice to the desired viewport.
		/// </summary>
		/// <param name="device">The GraphicsDevice.</param>
		/// <param name="location">The desired viewport location to set.</param>
		public static void SetViewport(this GraphicsDevice device, ViewportLocation location)
		{
			Viewport viewport = new Viewport { MinDepth = 0f, MaxDepth = 1f };

			switch (location)
			{
				case ViewportLocation.FullScreen:
					viewport.X = 0;
					viewport.Y = 0;
					viewport.Width = device.PresentationParameters.BackBufferWidth;
					viewport.Height = device.PresentationParameters.BackBufferHeight;
					break;
				case ViewportLocation.TopHalf:
					viewport.X = 0;
					viewport.Y = 0;
					viewport.Width = device.PresentationParameters.BackBufferWidth;
					viewport.Height = device.PresentationParameters.BackBufferHeight / 2;
					break;
				case ViewportLocation.BottomHalf:
					viewport.X = 0;
					viewport.Y = device.PresentationParameters.BackBufferHeight / 2;
					viewport.Width = device.PresentationParameters.BackBufferWidth;
					viewport.Height = device.PresentationParameters.BackBufferHeight / 2;
					break;
				case ViewportLocation.LeftHalf:
					viewport.X = 0;
					viewport.Y = 0;
					viewport.Width = device.PresentationParameters.BackBufferWidth / 2;
					viewport.Height = device.PresentationParameters.BackBufferHeight;
					break;
				case ViewportLocation.RightHalf:
					viewport.X = device.PresentationParameters.BackBufferWidth / 2;
					viewport.Y = 0;
					viewport.Width = device.PresentationParameters.BackBufferWidth / 2;
					viewport.Height = device.PresentationParameters.BackBufferHeight;
					break;
				case ViewportLocation.TopLeftQuarter:
					viewport.X = 0;
					viewport.Y = 0;
					viewport.Width = device.PresentationParameters.BackBufferWidth / 2;
					viewport.Height = device.PresentationParameters.BackBufferHeight / 2;
					break;
				case ViewportLocation.TopRightQuarter:
					viewport.X = device.PresentationParameters.BackBufferWidth / 2;
					viewport.Y = 0;
					viewport.Width = device.PresentationParameters.BackBufferWidth / 2;
					viewport.Height = device.PresentationParameters.BackBufferHeight / 2;
					break;
				case ViewportLocation.BottomLeftQuarter:
					viewport.X = 0;
					viewport.Y = device.PresentationParameters.BackBufferHeight / 2;
					viewport.Width = device.PresentationParameters.BackBufferWidth / 2;
					viewport.Height = device.PresentationParameters.BackBufferHeight / 2;
					break;
				case ViewportLocation.BottomRightQuarter:
					viewport.X = device.PresentationParameters.BackBufferWidth / 2;
					viewport.Y = device.PresentationParameters.BackBufferHeight / 2;
					viewport.Width = device.PresentationParameters.BackBufferWidth / 2;
					viewport.Height = device.PresentationParameters.BackBufferHeight / 2;
					break;
			}

			device.Viewport = viewport;
		}
	}
}