using System;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using S22.Xmpp;
using S22.Xmpp.Client;
using S22.Xmpp.Im;

namespace XmppBotDemo
{
	public static class MainClass
	{
		private static XmppClient client;
		private static Jid ourJid = null;
		private static string password = null;

		public static int Main(string[] args)
		{
			// Read in the environment variables
			ourJid = new Jid(Environment.GetEnvironmentVariable("XMPP_JID"));
			password = Environment.GetEnvironmentVariable("XMPP_PASSWORD");

			// Ensure they are present
			if (ourJid == null || password == null) {
				Console.Error.WriteLine("XMPP Bot Demo");
				Console.Error.WriteLine("=============");
				Console.Error.WriteLine("");
				Console.Error.WriteLine("Usage:");
				Console.Error.WriteLine("    ./XmppBotDemo.exe");
				Console.Error.WriteLine("");
				Console.Error.WriteLine("Environment Variables:");
				Console.Error.WriteLine("    XMPP_JID         Required. Specifies the JID to login with.");
				Console.Error.WriteLine("    XMPP_PASSWORD    Required. Specifies the password to login with.");
				return 1;
			}

			// Create the client instance
			client = new XmppClient(ourJid.Domain, ourJid.Node, password);

			client.Error += errorHandler;
			client.SubscriptionRequest += subscriptionRequestHandler;
			client.Message += messageHandler;

			client.Connect();

			// Wait for a connection
			while (!client.Connected)
				Thread.Sleep(100);

			Console.WriteLine($"[Main] Connected as {ourJid}.");

			// Wait forever.
			Thread.Sleep(Timeout.Infinite);

			// TODO: Automatically reconnect to the server when we get disconnected.

			return 0;
		}


		#region Event Handlers

		/// <summary>
		/// Handles requests to talk to us.
		/// </summary>
		/// <remarks>
		/// Only allow people to talk to us if they are on the same domain we are.
		/// You probably don't want this for production, but for developmental purposes
		/// it offers some measure of protection.
		/// </remarks>
		/// <param name="from">The JID of the remote user who wants to talk to us.</param>
		/// <returns>Whether we're going to allow the requester to talk to us or not.</returns>
		public static bool subscriptionRequestHandler(Jid from) {
			Console.WriteLine($"[Handler/SubscriptionRequest] {from} is requesting access, I'm saying {(from.Domain == ourJid.Domain?"yes":"no")}");
			return from.Domain == ourJid.Domain;
		}

		/// <summary>
		/// Handles incoming messages.
		/// </summary>
		private static void messageHandler(object sender, MessageEventArgs eventArgs) {
			Console.WriteLine($"[Handler/Message] {eventArgs.Message.Body.Length} chars from {eventArgs.Jid}");
			char[] messageCharArray = eventArgs.Message.Body.ToCharArray();
			Array.Reverse(messageCharArray);
			sendChatReply(
				eventArgs.Message,
				new string(messageCharArray)
			);
		}

		/// <summary>
		/// Handles any errors thrown by the XMPP client engine.
		/// </summary>
		private static void errorHandler(object sender, ErrorEventArgs eventArgs) {
			Console.Error.WriteLine($"Error: {eventArgs.Reason}");
			Console.Error.WriteLine(eventArgs.Exception);
		}

		#endregion

		#region Message Senders

		/// <summary>
		/// Sends a chat message to the specified JID.
		/// </summary>
		/// <param name="to">The JID to send the message to.</param>
		/// <param name="message">The messaage to send.</param>
		private static void sendChatMessage(Jid to, string message)
		{
			//Console.WriteLine($"[Rhino/Send/Chat] Sending {message} -> {to}");
			client.SendMessage(
				to, message,
				null, null, MessageType.Chat
			);
		}
		/// <summary>
		/// Sends a chat message in direct reply to a given incoming message.
		/// </summary>
		/// <param name="originalMessage">Original message.</param>
		/// <param name="reply">Reply.</param>
		private static void sendChatReply(Message originalMessage, string reply)
		{
			//Console.WriteLine($"[Rhino/Send/Reply] Sending {reply} -> {originalMessage.From}");
			client.SendMessage(
				originalMessage.From, reply,
				null, originalMessage.Thread, MessageType.Chat
			);
		}


		#endregion
	}
}