using System;
using System.Collections.Generic;
using System.Net;
using System.Text;
using System.Text.Json;
using System.Threading;
using Telegram.Bot;

namespace ZaoBot
{
	class NotificationReceiver
	{
		private JsonDocument config;

		public NotificationReceiver(JsonDocument config)
		{
			this.config = config;
		}

		public void Run()
		{
			while (true)
			{
				try
				{
					var port = config.RootElement.GetProperty("notify_listen_port").GetInt32();
					var listener = new HttpListener();
					listener.Prefixes.Add("http://+:" + port + "/");
					listener.Start();
					Console.WriteLine("NotificationReceiver listening on port " + port);
					ProcessRequests(listener);
					listener.Stop();
				}
				catch (Exception e)
				{
					Console.WriteLine("NotificationReceiver exception: " + e.Message + "\n" + e.StackTrace);
					Thread.Sleep(1000);
				}
			}
		}

		private void ProcessRequests(HttpListener listener)
		{
			while (true)
			{
				var context = listener.GetContext();
				HttpListenerRequest request = context.Request;
				var message = request.QueryString.Get("message");
				if (string.IsNullOrEmpty(message))
				{
					RespondWith(context, "FAIL");
				}
				else
				{
					SendNotification(message);
					RespondWith(context, "OK");
				}
			}
		}

		private async void SendNotification(string message)
		{
			var token = config.RootElement.GetProperty("token").GetString();
			var botClient = new TelegramBotClient(token);
			foreach(var element in config.RootElement.GetProperty("notify_user_ids").EnumerateArray())
			{
				await botClient.SendTextMessageAsync(
							chatId: element.GetString(),
							text: message
				);
			}
		}

		private void RespondWith(HttpListenerContext context, string v)
		{

			HttpListenerResponse response = context.Response;
			string responseString = v;
			byte[] buffer = Encoding.UTF8.GetBytes(responseString);
			response.ContentLength64 = buffer.Length;
			System.IO.Stream output = response.OutputStream;
			output.Write(buffer, 0, buffer.Length);
			output.Close();
		}
	}
}