using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace DD2Switcher;

internal static class Program {
	private static int NumProc = 10;
	private static Process[] windows = new Process[NumProc];
	private static int ActiveIndex = -1;

	private static readonly IntPtr defaultAffinity = new(0xFF000000);
	private static readonly IntPtr fullAffinity = new(0xFFFFFFFF);

	[DllImport("user32.dll")]
	public static extern IntPtr GetForegroundWindow();

	[DllImport("user32.dll")]
	public static extern bool SetForegroundWindow(IntPtr hWnd);

	[DllImport("kernel32.dll", SetLastError = true)]
	[return: MarshalAs(UnmanagedType.Bool)]
	static extern bool AllocConsole();

	private static void CleanWindows() {
		for (int i = 0; i < NumProc; i++) {
			var window = windows[i];
			if (window == null) continue;
			if (window.MainWindowHandle == IntPtr.Zero) {
				Console.WriteLine($"Window at index {i} has no main window, removing from tracked windows");
				windows[i] = null;
			}
		}
	}

	private static void AdjustAffinities() {
		CleanWindows();
		for (int i = 0; i < NumProc; i++) {
			var window = windows[i];
			if (window == null) continue;
			if (i != ActiveIndex) {
				try {
					window.ProcessorAffinity = defaultAffinity;
				}
				catch (Exception e) {
					windows[i] = null;
				}
			}
		}

		var active = windows[ActiveIndex];
		if (active != null) {
			try {
				active.ProcessorAffinity = fullAffinity;
			}
			catch (Exception e) {
				windows[ActiveIndex] = null;
			}
		}
	}

	private static void AdjustPriorities() {
		CleanWindows();
		for (int i = 0; i < NumProc; i++) {
			var window = windows[i];
			if (window == null) continue;

			if (i != ActiveIndex) {
				try {
					window.PriorityClass = ProcessPriorityClass.Idle;
				}
				catch (Exception e) {
					windows[i] = null;
				}
			}
		}

		var active = windows[ActiveIndex];
		if (active != null) {
			try {
				active.PriorityClass = ProcessPriorityClass.High;
			}
			catch (Exception e) {
				windows[ActiveIndex] = null;
			}
		}
	}

	private static Process GetForegroundProcess() {
		var foregroundWindow = GetForegroundWindow();
		var process = Process.GetProcesses();
		Process foregroundProcess = null;
		foreach (var p in process)
			if (foregroundWindow == p.MainWindowHandle) {
				foregroundProcess = p;
				break;
			}

		if (foregroundProcess == null) return null;
		return foregroundProcess;
	}

	private static Boolean ProcessTracked(int id) {
		for (int i = 0; i < NumProc; i++) {
			if (windows[i] != null && windows[i].Id == id) {
				return true;
			}
		}

		return false;
	}

	private static void Track(Process process) {
		for (int i = 0; i < NumProc; i++) {
			if (windows[i] == null) {
				windows[i] = process;
				Console.WriteLine($"Added {process.ProcessName} to tracked windows at index {i}");
				return;
			}
		}
	}

	private static void TrackWows() {
		CleanWindows();
		var processes = Process.GetProcesses();
		foreach (var process in processes) {
			if (process.ProcessName == "UWow-64") {
				Console.WriteLine($"Found UWow-64 at pid {process.Id}");
				if (ProcessTracked(process.Id))
					continue;
				Track(process);
			}
		}
	}

	private static void Swap(int index) {
		index = (index - 1) % NumProc;
		if (index < 0) index = NumProc - 1;
		if (index >= NumProc) return;
		Console.WriteLine($"Swapping window at index {index}");
		var process = GetForegroundProcess();
		if (process == null) return;
		Console.WriteLine($"Foreground process: {process}");
		bool found = false;

		for (int i = 0; i < NumProc; i++) {
			var window = windows[i];
			if (window != null && window.Id == process.Id) {
				found = true;
				break;
			}
		}

		if (!found) {
			for (int i = 0; i < NumProc; i++) {
				var window = windows[i];
				if (window == null) {
					Console.WriteLine($"Adding foreground window to tracked at index {i}...");
					windows[i] = process;
				}
			}
		}

		for (int i = 0; i < NumProc; i++) {
			var window = windows[i];
			if (window != null && window.Id == process.Id) {
				windows[i] = windows[index];
				windows[index] = window;
				Console.WriteLine($"Swapped window at index {i} to {index}");
				return;
			}
		}
	}

	private static void TabTo(int index) {
		index = (index - 1) % NumProc;
		if (index < 0) index = NumProc - 1;
		if (index >= NumProc) return;
		Console.WriteLine($"Tab to window at index {index}");

		var window = windows[index];
		if (window == null || window.MainWindowHandle == IntPtr.Zero) {
			Console.WriteLine($"Window at index {index} does not exist, removing from tracked windows");
			windows[index] = null;
		}
		else {
			SetForegroundWindow(window.MainWindowHandle);
			ActiveIndex = index;
			AdjustAffinities();
			AdjustPriorities();
		}
	}

	[STAThread]
	private static void Main() {
		//AllocConsole();

		var processes = Process.GetProcesses();
		var currentProcess = Process.GetCurrentProcess();

		foreach (var process in processes)
			if (process.Id != currentProcess.Id && process.ProcessName == currentProcess.ProcessName) {
				process.Kill();
				Process.GetCurrentProcess().Kill();
			}

		for (int i = 0; i < NumProc; i++) {
			windows[i] = null;
			HotKeyManager.RegisterHotKey(Keys.D0 + i, KeyModifiers.Alt);
			HotKeyManager.RegisterHotKey(Keys.D0 + i, KeyModifiers.Alt | KeyModifiers.Shift);
		}

		HotKeyManager.RegisterHotKey(Keys.Oemtilde, KeyModifiers.Alt);
		HotKeyManager.HotKeyPressed += HotKeyManager_HotKeyPressed;

		static void HotKeyManager_HotKeyPressed(object sender, HotKeyEventArgs e) {
			if (e.Key == Keys.Oemtilde && e.Modifiers == KeyModifiers.Alt) {
				TrackWows();
				return;
			}

			if (e.Modifiers == KeyModifiers.Alt) {
				TabTo(e.Key - Keys.D0);
			}
			else if (e.Modifiers == (KeyModifiers.Alt | KeyModifiers.Shift)) {
				Swap(e.Key - Keys.D0);
			}
		}


		Console.CancelKeyPress += (sender, e) => { Process.GetCurrentProcess().Kill(); };
		while (true)
			System.Threading.Thread.Sleep(100000);
	}
}