using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Threading.Tasks;
using S22.Xmpp;
using S22.Xmpp.Client;
using S22.Xmpp.Im;

namespace RhinoReminds
{
	public class ProgramSettings
	{
		public string AllowedDomain = "*";
		public string Filepath = "./reminders.xml";
		public string Jid = null;

		public string AvatarFilepath = string.Empty;
		public string PidFile = null;

		public string Password = null;
	}

	public static class Program
	{
		private static ProgramSettings settings = new ProgramSettings();

		public static int Main(string[] args)
		{
			List<string> extras = new List<string>();
			for (int i = 0; i < args.Length; i++)
			{
				if (!args[i].StartsWith("-")) {
					extras.Add(args[i]);
					continue;
				}

				switch (args[i]) {
					case "-h":
					case "--help":
						Console.WriteLine("--- RhinoReminds ---");
						Console.WriteLine("> An XMPP reminder bot");
						Console.WriteLine("    By Starbeamrainbowlabs");
						Console.WriteLine();
						Console.WriteLine("Usage:");
						Console.WriteLine("    mono RhinoReminds.exe {options}");
						Console.WriteLine();
						Console.WriteLine("Options:");
						Console.WriteLine("    -h  --help    Show this message");
						Console.WriteLine($"    -f  --file    Specify where to save reminders (default: {settings.Filepath})");
						Console.WriteLine("        --domain {domain}  Set the domain users are allowed to originate at. Defaults to any domain.");
						Console.WriteLine("        --avatar  Update the XMPP account's avatar to the specified image. By default the avatar is not updated.");
						Console.WriteLine("        --pidfile Save our process ID to the specified file, and delete it on exit");
						Console.WriteLine();
						Console.WriteLine("Environment Variables:");
						Console.WriteLine("    XMPP_JID       The JID to login to");
						Console.WriteLine("    XMPP_PASSWORD  The password to login with");
						return 0;

					case "--jid":
						settings.Jid = args[++i];
						break;

					case "-d":
					case "--domain":
						settings.AllowedDomain = args[++i];
						break;


					case "--avatar":
						settings.AvatarFilepath = args[++i];
						break;

					case "--pidfile":
						settings.PidFile = args[++i];
						break;

					default:
						Console.Error.WriteLine($"Error: Unknown argument '{args[i]}'.");
						return 14;
				}
			}

			settings.Jid = Environment.GetEnvironmentVariable("XMPP_JID");
			settings.Password = Environment.GetEnvironmentVariable("XMPP_PASSWORD");

			if (settings.Jid == null) {
				Console.Error.WriteLine("Error: No JID specified to login with."); 
				Console.Error.WriteLine("Do so with the XMPP_JID environment variable!");
				return 15;
			}
			if (settings.Password == null) {
				Console.Error.WriteLine("Error: No password specified to login with.");
				Console.Error.WriteLine("Do so with the XMPP_PASSWORD environment variable!");
				return 16;
			}

			if (settings.PidFile != null)
				setupPidFile();

			run();
			// We shouldn't ever end up here, but just in case.....
			cleanupPidFile();
			return 0;
		}

		private static void setupPidFile()
		{
			File.WriteAllText(settings.PidFile, Process.GetCurrentProcess().Id.ToString());
			AppDomain.CurrentDomain.ProcessExit += (object sender, EventArgs e) => cleanupPidFile();
			AppDomain.CurrentDomain.DomainUnload += (object sender, EventArgs e) => cleanupPidFile();
		}

		private static void cleanupPidFile() {
			// Make sure we only do cleanup once
			if (settings.PidFile == null)
				return;

			File.Delete(settings.PidFile);
			settings.PidFile = null;
		}

		private static void run()
		{
			ClientListener client = new ClientListener(settings.Jid, settings.Password) {
				ReminderFilePath = settings.Filepath
			};
			client.AllowedDomains.Add(settings.AllowedDomain);
			// Update the avatar if appropriate
			if (settings.AvatarFilepath != string.Empty) {
				OnConnectedHandler handler = null;
				handler = (object sender, OnConnectedEventArgs eventArgs) => {
					client.SetAvatar(settings.AvatarFilepath);
					Console.WriteLine($"[Program] Set avatar to '{settings.AvatarFilepath}'.");
					client.OnConnected -= handler;
				};
				client.OnConnected += handler;
			}
			// Connect to the server & start listening
			// Make sure the program doesn't exit whilst we're connected
			try
			{
				client.Start().Wait();
			} catch (Exception) {
				// Ensure we tidy up after ourselves by deleting the PID file
				if (settings.PidFile != null)
					cleanupPidFile();
				// Re-throw the error
				throw;
			}
		}
	}
}