using System;
using System.Diagnostics;
using System.IO;
using System.Text.RegularExpressions;
using System.Threading;

class FileWatcher {
	static SemaphoreSlim semaphore = new SemaphoreSlim(0, 1);
	static string lockFilePath = Path.Combine(Path.GetTempPath(), "ZitiDesktopEdgeUpdateSentinelLock.txt");
	static string pathToWatch = @"C:\Program Files (x86)\NetFoundry, Inc\Ziti Desktop Edge\ZitiDesktopEdge.exe";

	static void Main() {
		Console.CancelKeyPress += OnCancelKeyPress;
		AppDomain.CurrentDomain.ProcessExit += OnProcessExit;
		// Check if the lock file exists
		if (File.Exists(lockFilePath)) {

			try {
				File.Delete(lockFilePath);
				Console.WriteLine("Found stale lock file and removed it.");
			} catch {
				AppDomain.CurrentDomain.ProcessExit -= OnProcessExit;
				Console.WriteLine("The program is already running. Exiting.");
				return;
			}
		}

		Console.WriteLine($"{lockFilePath} does not exist");
		var f = File.Create(lockFilePath);
		try {
			// Create or overwrite the log file
			string logFilePath = Path.Combine(Path.GetTempPath(), "ZitiDesktopEdgeUpdateSentinel.log");
			using (StreamWriter logWriter = new StreamWriter(logFilePath, false)) {
				// Redirect console output to the log file
				Console.WriteLine($"Upgrade started. Waiting for the upgrade to complete.");
				Console.WriteLine($"Log file created at: {logFilePath}");
				var outwriter = Console.Out;
				Console.SetOut(logWriter);
				if (File.Exists(pathToWatch)) {
					Console.WriteLine($"File exists: {pathToWatch}");
				}
				WatchForFile(pathToWatch);

				Thread.Sleep(1000);
				// Start the process
				Console.WriteLine($"Starting {pathToWatch}");
				using (Process process = new Process()) {
					process.StartInfo.FileName = pathToWatch;
					process.StartInfo.Arguments = "version";
					process.StartInfo.RedirectStandardOutput = true;
					process.StartInfo.UseShellExecute = false;
					process.StartInfo.CreateNoWindow = true;
					process.Start();
					Console.WriteLine($"Started {pathToWatch}");
				}
				logWriter.Flush();
				Console.SetOut(outwriter);
			}
		} finally {
			// Delete the lock file from the user's temporary folder to allow the program to run next time
			f.Close();
			File.Delete(lockFilePath);
		}
	}


	static void OnCancelKeyPress(object sender, ConsoleCancelEventArgs e) {
		Console.WriteLine("Ctrl+C detected. Cleaning up...");
		try {
			// Delete the lock file upon termination
			if (File.Exists(lockFilePath)) {
				File.Delete(lockFilePath);
				Console.WriteLine("Lock file deleted.");
			}
		} catch { }
	}

	static void OnProcessExit(object sender, EventArgs e) {
		Console.WriteLine("Process is exiting. Cleaning up...");
		OnCancelKeyPress(sender, null);
	}

	static void WatchForFile(string filePath) {
		// Extract the directory path from the file path
		string directoryPath = Path.GetDirectoryName(filePath);

		// Create a new FileSystemWatcher instance
		FileSystemWatcher watcher = new FileSystemWatcher();

		// Set the path to watch (the directory containing the file)
		watcher.Path = directoryPath;

		// Watch only the specified file
		watcher.Filter = Path.GetFileName(filePath);

		// Subscribe to events
		watcher.Created += OnFileCreated;
		watcher.Deleted += OnFileDeleted;
		watcher.Renamed += OnFileRenamed;

		// Enable the FileSystemWatcher
		watcher.EnableRaisingEvents = true;

		Console.WriteLine($"Watching for changes to file '{filePath}'...");
		semaphore.Wait();
	}

	static void OnFileCreated(object sender, FileSystemEventArgs e) {
		Console.WriteLine($"File created: {e.FullPath}");
		semaphore.Release();
	}

	static void OnFileDeleted(object sender, FileSystemEventArgs e) {
		Console.WriteLine($"File deleted: {e.FullPath}");

		// Uncomment the line below if you want to stop watching after the file is deleted
		// ((FileSystemWatcher)sender).EnableRaisingEvents = false;
	}

	static void OnFileRenamed(object sender, FileSystemEventArgs e) {
		Console.WriteLine($"File renamed: {e.FullPath}");

		// Uncomment the line below if you want to stop watching after the file is deleted
		// ((FileSystemWatcher)sender).EnableRaisingEvents = false;
	}
}