using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Windows;

using Microsoft.Research.DynamicDataDisplay.Common;

using System.Diagnostics;

using System.Windows.Media;



namespace Microsoft.Research.DynamicDataDisplay

{

	/// <summary>

	/// A central class in 2d coordinate transformation in DynamicDataDisplay.

	/// Provides methods to transform point from one coordinate system to another.

	/// Should be immutable.

	/// </summary>

	public sealed class CoordinateTransform

	{

		private CoordinateTransform(DataRect visibleRect, Rect screenRect)

		{

			this.visibleRect = visibleRect;

			this.screenRect = screenRect;



			rxToScreen = screenRect.Width / visibleRect.Width;

			ryToScreen = screenRect.Height / visibleRect.Height;

			cxToScreen = visibleRect.XMin * rxToScreen - screenRect.Left;

			cyToScreen = screenRect.Height + screenRect.Top + visibleRect.YMin * ryToScreen;



			rxToData = visibleRect.Width / screenRect.Width;

			ryToData = visibleRect.Height / screenRect.Height;

			cxToData = screenRect.Left * rxToData - visibleRect.XMin;

			cyToData = visibleRect.Height + visibleRect.YMin + screenRect.Top * ryToData;

		}



		#region Coeffs

		double rxToScreen;

		double ryToScreen;

		double cxToScreen;

		double cyToScreen;



		double rxToData;

		double ryToData;

		double cxToData;

		double cyToData;

		#endregion



		#region Creation methods



		/// <summary>

		/// Creates CoordinateTransform fro specified rectangles and with Identity transform.

		/// </summary>

		/// <param name="visibleRect">The visible rect.</param>

		/// <param name="screenRect">The screen rect.</param>

		/// <returns></returns>

		public static CoordinateTransform FromRects(DataRect visibleRect, Rect screenRect)

		{

			CoordinateTransform result = new CoordinateTransform(visibleRect, screenRect);

			return result;

		}



		/// <summary>

		/// Closnes transform with current dataTransform and specified rectangles.

		/// </summary>

		/// <param name="visibleRect">The visible rect.</param>

		/// <param name="screenRect">The screen rect.</param>

		/// <returns></returns>

		public CoordinateTransform WithRects(DataRect visibleRect, Rect screenRect)

		{

			CoordinateTransform copy = new CoordinateTransform(visibleRect, screenRect);

			copy.dataTransform = dataTransform;

			return copy;

		}



		/// <summary>

		/// Creates a new instance of CoordinateTransform with the given data transform.

		/// </summary>

		/// <param name="dataTransform">The data transform.</param>

		/// <returns></returns>

		public CoordinateTransform WithDataTransform(DataTransform dataTransform)

		{

			if (dataTransform == null)

				throw new ArgumentNullException("dataTransform");



			CoordinateTransform copy = new CoordinateTransform(visibleRect, screenRect);

			copy.dataTransform = dataTransform;

			return copy;

		}



		internal CoordinateTransform WithScreenOffset(double x, double y)

		{

			Rect screenCopy = screenRect;

			screenCopy.Offset(x, y);

			CoordinateTransform copy = new CoordinateTransform(visibleRect, screenCopy);

			return copy;

		}



		internal static CoordinateTransform CreateDefault()

		{

			CoordinateTransform transform = new CoordinateTransform(new Rect(0, 0, 1, 1), new Rect(0, 0, 1, 1));



			return transform;

		}



		#endregion



		#region Transform methods



		/// <summary>

		/// Transforms point from data coordinates to screen.

		/// </summary>

		/// <param name="dataPoint">The point in data coordinates.</param>

		/// <returns></returns>

		public Point DataToScreen(Point dataPoint)

		{

			Point viewportPoint = dataTransform.DataToViewport(dataPoint);



			Point screenPoint = new Point(viewportPoint.X * rxToScreen - cxToScreen,

				cyToScreen - viewportPoint.Y * ryToScreen);



			return screenPoint;

		}



		/// <summary>

		/// Transforms point from screen coordinates to data coordinates.

		/// </summary>

		/// <param name="screenPoint">The point in screen coordinates.</param>

		/// <returns></returns>

		public Point ScreenToData(Point screenPoint)

		{

			Point viewportPoint = new Point(screenPoint.X * rxToData - cxToData,

				cyToData - screenPoint.Y * ryToData);



			Point dataPoint = dataTransform.ViewportToData(viewportPoint);



			return dataPoint;

		}



		/// <summary>

		/// Transforms point from viewport coordinates to screen coordinates.

		/// </summary>

		/// <param name="viewportPoint">The point in viewport coordinates.</param>

		/// <returns></returns>

		public Point ViewportToScreen(Point viewportPoint)

		{

			Point screenPoint = new Point(viewportPoint.X * rxToScreen - cxToScreen,

				cyToScreen - viewportPoint.Y * ryToScreen);



			return screenPoint;

		}



		/// <summary>

		/// Transforms point from screen coordinates to viewport coordinates.

		/// </summary>

		/// <param name="screenPoint">The point in screen coordinates.</param>

		/// <returns></returns>

		public Point ScreenToViewport(Point screenPoint)

		{

			Point viewportPoint = new Point(screenPoint.X * rxToData - cxToData,

				cyToData - screenPoint.Y * ryToData);



			return viewportPoint;

		}



		#endregion



		[DebuggerBrowsable(DebuggerBrowsableState.Never)]

		private DataRect visibleRect;

		/// <summary>

		/// Gets the viewport rectangle.

		/// </summary>

		/// <value>The viewport rect.</value>

		public DataRect ViewportRect

		{

			get { return visibleRect; }

		}



		[DebuggerBrowsable(DebuggerBrowsableState.Never)]

		private Rect screenRect;

		/// <summary>

		/// Gets the screen rectangle.

		/// </summary>

		/// <value>The screen rect.</value>

		public Rect ScreenRect

		{

			get { return screenRect; }

		}



		[DebuggerBrowsable(DebuggerBrowsableState.Never)]

		private DataTransform dataTransform = DataTransforms.Identity;

		/// <summary>

		/// Gets the data transform.

		/// </summary>

		/// <value>The data transform.</value>

		public DataTransform DataTransform

		{

			get { return dataTransform; }

		}

	}

}