using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Runtime.InteropServices;
using System.Windows.Interop;

namespace BuzzGUI.Common
{
    public static class WPFExtensions
    {
		static int dpi = -1;
		static object _dpiLock = new object();

		public static int DPI
		{
			get
			{
				if (dpi < 0)
				{
					lock (_dpiLock)
					{
						IntPtr dc = Win32.GetDC(IntPtr.Zero);
						if (dc == IntPtr.Zero) { dpi = 96; return dpi; }
						dpi = Win32.GetDeviceCaps(dc, Win32.DeviceCap.LOGPIXELSY);
						Win32.ReleaseDC(IntPtr.Zero, dc);
					}
				}

				return dpi;
			}
		}

		public static float PixelsPerDip { get { return ((float)DPI) / 96; } }

		public static double RoundDipForDisplayMode(double value)
		{
			return RoundDipForDisplayMode(value, MidpointRounding.ToEven);
		}

		static double RoundDipForDisplayMode(double value, MidpointRounding midpointRounding)
		{
			return Math.Round(value * PixelsPerDip, midpointRounding) / PixelsPerDip;
		}

		public static T GetAncestor<T>(this DependencyObject e) where T : DependencyObject
		{
			do
			{
				e = VisualTreeHelper.GetParent(e);
			} while (e != null && !(e is T));

			return (T)e;
		}

        public static Rect TranslateRect(this UIElement e, UIElement x, Rect r)
        {
            return new Rect(e.TranslatePoint(r.TopLeft, x), e.TranslatePoint(r.BottomRight, x));
        }

        public static Rect GetBounds(this UIElement e, UIElement x)
        {
            Point tl = e.TranslatePoint(new Point(0, 0), x);
            Point bl = e.TranslatePoint(new Point(e.RenderSize.Width, e.RenderSize.Height), x);
            return new Rect(tl, bl);
        }

		public static bool IsPointInside(this UIElement e, Point p)
		{
			return p.X >= 0 && p.Y >= 0 && p.X < e.RenderSize.Width && p.Y < e.RenderSize.Height;
		}

        public static Point GetCenter(this Rect r)
        {
            return new Point(r.Left + r.Width / 2, r.Top + r.Height / 2);
        }

        public static Vector ElementMul(this Vector a, Vector b) { return new Vector(a.X * b.X, a.Y * b.Y); }
        public static Vector ElementDiv(this Vector a, Vector b) { return new Vector(a.X / b.X, a.Y / b.Y); }

        public static Point Clamp(this Point p, double min, double max)
        {
            return new Point(Math.Min(Math.Max(p.X, min), max), Math.Min(Math.Max(p.Y, min), max));
        }

		public static Color Blend(this Color c, Color d, double a)
		{
			return Color.FromArgb(
				(byte)(a * c.A + (1 - a) * d.A),
				(byte)(a * c.R + (1 - a) * d.R),
				(byte)(a * c.G + (1 - a) * d.G),
				(byte)(a * c.B + (1 - a) * d.B));
		}
		
		public static int GetPerceivedBrightness(this Color c)
		{
			return (int)Math.Sqrt(c.R * c.R * .299 + c.G * c.G * .587 + c.B * c.B * .114);
		}

		public static Color EnsureContrast(this Color fg, Color bg)
		{
			var fb = fg.GetPerceivedBrightness();
			var bb = bg.GetPerceivedBrightness();

			if (Math.Abs(fb - bb) < 64)
			{
				if (bb >= 128)
					return Colors.Black;
				else
					return Colors.White;
			}
			else
			{
				return fg;
			}
		}

		public static bool IsMouseOnEdgeOrOutsideScreen(this Visual visual)
		{
			var p = Win32Mouse.GetScreenPosition();
			var r = WPFScreen.GetScreenFrom(visual).DeviceBounds;
			r.X++;
			r.Y++;
			r.Width -= 3;
			r.Height -= 3;
			return !r.Contains(p);
		}

		[DllImport("user32.dll", SetLastError=true)]
		static extern bool BringWindowToTop(IntPtr hWnd);

		public static bool BringToTop(this Window wnd)
		{
			return BringWindowToTop(new WindowInteropHelper(wnd).Handle);
		}

		public static Size GetTotalNonclientAreaSize(this Window wnd)
		{
			switch (wnd.WindowStyle)
			{
				case WindowStyle.ThreeDBorderWindow:
					throw new Exception("not supported");

				case WindowStyle.SingleBorderWindow:
					if (wnd.ResizeMode == ResizeMode.CanResize || wnd.ResizeMode == ResizeMode.CanResizeWithGrip)
						return new Size(2 * SystemParameters.ResizeFrameVerticalBorderWidth, System.Windows.Forms.SystemInformation.CaptionHeight + 2 * SystemParameters.ResizeFrameHorizontalBorderHeight);
					else
						return new Size(2 * SystemParameters.FixedFrameVerticalBorderWidth, System.Windows.Forms.SystemInformation.CaptionHeight + 2 * SystemParameters.FixedFrameHorizontalBorderHeight);

				case WindowStyle.ToolWindow:
					if (wnd.ResizeMode == ResizeMode.CanResize || wnd.ResizeMode == ResizeMode.CanResizeWithGrip)
						return new Size(2 * SystemParameters.ResizeFrameVerticalBorderWidth, System.Windows.Forms.SystemInformation.ToolWindowCaptionHeight + 2 * SystemParameters.ResizeFrameHorizontalBorderHeight);
					else
						return new Size(2 * SystemParameters.FixedFrameVerticalBorderWidth, System.Windows.Forms.SystemInformation.ToolWindowCaptionHeight + 2 * SystemParameters.FixedFrameHorizontalBorderHeight);

				default:
					if (wnd.ResizeMode == ResizeMode.CanResize || wnd.ResizeMode == ResizeMode.CanResizeWithGrip)
						throw new Exception("not supported");
					else
						return new Size(0, 0);
			}	
		}

    }
}