using System;
using System.IO;
using System.Net;
using System.Threading.Tasks;

namespace TBConsole
{
    public class WebServer
    {
        private bool _running;
        private readonly HttpListener _listener = new HttpListener();
        private readonly Func<string, string> _commandReceiver;
        private readonly Func<string> _commandsListSender;

        public WebServer(Func<string, string> commandReceiver, Func<string> commandsListSender)
        {
            _commandReceiver = commandReceiver;
            _commandsListSender = commandsListSender;
        }

        public void Start()
        {
            _running = true;
            KeepListening();
        }

        public void Stop()
        {
            _running = false;
            _listener.Stop();
        }
        
        private async void KeepListening()
        {
            _listener.Prefixes.Add("http://localhost:8019/");
            _listener.Start();
            while (_running)
            {
                try
                {
                    var context = await _listener.GetContextAsync();
                    string request = await new StreamReader(context.Request.InputStream).ReadToEndAsync();
                    string resp;
                    switch (context.Request.Url.AbsolutePath)
                    {
                        case "/command":
                            resp = _commandReceiver(request);
                            break;
                        case "/commands":
                            resp = _commandsListSender();
                            break;
                        default:
                            resp = "<img src=\"https://http.cat/404\">";
                            break;
                    }
                    string origin = context.Request.Headers["Origin"];
                    if (origin == "http://localhost:4200" || origin == "https://tb-console.web.app")
                        context.Response.AddHeader("Access-Control-Allow-Origin", origin);
                    var sw = new StreamWriter(context.Response.OutputStream);
                    await sw.WriteLineAsync(resp);
                    sw.Close();
                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                }
            }
        }
    }
}