using System;
using System.Collections.Generic;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Linq;

// The 'windowHandle' parameter will contain the window handle for the:
//   - Active window when run by hotkey
//   - Window Location target when run by a Window Location rule
//   - TitleBar Button owner when run by a TitleBar Button
//   - Jump List owner when run from a Taskbar Jump List
//   - Currently focused window if none of these match
public static class DisplayFusionFunction
{
	[DllImport("user32.dll", SetLastError = true)]
	private static extern IntPtr GetWindow(IntPtr hWnd, uint uCmd);
	
	//some constants
	const uint GW_HWNDNEXT = 2;
	
	public static void Run(IntPtr windowHandle)
	{
		// A list to hold the window handles
        List<IntPtr> windows = new List<IntPtr>();
		
		// A list to store the monitor ids from left to right
		List<uint> ids = new List<uint>( BFS.Monitor.GetMonitorIDs() );
		
		// Enumerate through the monitors from left to right
		// and get the topmost window for each monitor
		foreach(uint id in ids)		
			windows.Add(GetTopmostWindowOnMonitor(id));
		
		// Realign the monitor list by moving the last item to the front
		ids.Insert(0, ids.LastOrDefault());
		ids.RemoveAt(ids.Count - 1);
		
		// Move the windows
		for(int i = 0; (i < ids.Count) && (i < windows.Count); i++)		
			BFS.Window.MoveToMonitor(ids[i], windows[i]);		
	}
	
	private static IntPtr GetTopmostWindowOnMonitor(uint id)
	{
        //get the visible window handles for that monitor
        HashSet<IntPtr> visibleWindows = new HashSet<IntPtr>( BFS.Window.GetVisibleWindowHandlesByMonitor(id) );
	
        //enumerate through the monitors, starting with the focused window, and moving down
		//only enumerate if we havn't found the windows yet
		for(IntPtr window = BFS.Window.GetFocusedWindow(); ; window = GetWindow(window, GW_HWNDNEXT))
		{
			//check to see if there are no windows left
			if(window == IntPtr.Zero)
				break;
				
            //check to see if the window is visible. if it's not, ignore it
			if(!visibleWindows.Contains(window))
                continue;
				
			//if it is a window we should ignore, ignore it
			if(IsDisplayFusionWindowOrHiddenExplorerWindow(window))
				continue;
			
			//get the monitor this window is in
			uint monitor = BFS.Monitor.GetMonitorIDByWindow(window);
			
			//if the monitor isn't in our collection, get the next window
			if(id != monitor)
				continue;
				
			return window;
		}
	
        //return IntPtr.Zero if we didn't find anything
        return IntPtr.Zero;
	}
	
	private static bool IsDisplayFusionWindowOrHiddenExplorerWindow(IntPtr window)
	{
        //ignore any DisplayFusion windows (title bar buttons, etc.)
        //ignore pesky hidden explorer.exe windows
        if((BFS.Window.GetClass(window).StartsWith("DF", StringComparison.OrdinalIgnoreCase)) ||
            (BFS.Window.GetClass(window).Equals("EdgeUiInputTopWndClass", StringComparison.OrdinalIgnoreCase)) ||
            (BFS.Window.GetClass(window).Equals("EdgeUiInputWndClass", StringComparison.OrdinalIgnoreCase)) ||
            (BFS.Window.GetClass(window).Equals("NativeHWNDHost", StringComparison.OrdinalIgnoreCase)) ||
            (BFS.Window.GetClass(window).Equals("ModeInputWnd", StringComparison.OrdinalIgnoreCase)) ||
            (BFS.Window.GetClass(window).Equals("MetroGhostWindow", StringComparison.OrdinalIgnoreCase)) ||
            (BFS.Window.GetClass(window).Equals("ImmersiveLauncher", StringComparison.OrdinalIgnoreCase)) ||
            (BFS.Window.GetClass(window).Equals("ApplicationManager_ImmersiveShellWindow", StringComparison.OrdinalIgnoreCase)) ||
            (BFS.Window.GetClass(window).Equals("Shell_TrayWnd", StringComparison.OrdinalIgnoreCase)) ||
            (BFS.Window.GetClass(window).Equals("WorkerW", StringComparison.OrdinalIgnoreCase)) ||
            (BFS.Window.GetClass(window).Equals("Progman", StringComparison.OrdinalIgnoreCase)) ||
            (BFS.Window.GetClass(window).Equals("SearchPane", StringComparison.OrdinalIgnoreCase)))
        {
            return true;
        }
        
        return false;
	}
}