using System;
using System.Net;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using Domain;
using Domain.Dto;

namespace NetworkTest;

public class HttpServer : IServer
{
    private readonly HttpListener _listener;
    private readonly string _url;
    private CancellationTokenSource _cts = new CancellationTokenSource();
    private Func<long, Data?> _getData;
    private Action<Data, HttpListenerResponse> _writeResponse;

    public HttpServer(Func<long, Data?> getData, Action<Data, HttpListenerResponse> writeResponse, string url = "http://*:5555/")
    {
        _getData = getData;
        _writeResponse = writeResponse;
        _url = url;
        _listener = new HttpListener();
        _listener.Prefixes.Add(_url);
    }

    public void Start()
    {
        _cts = new CancellationTokenSource();
        _listener.Start();
        Task.Run(() => ListenAsync(_cts.Token));
    }

    public void Stop()
    {
        _cts.Cancel();
        _listener.Stop();
    }

    private async Task ListenAsync(CancellationToken token)
    {
        while (!token.IsCancellationRequested)
        {
            try
            {
                var context = await _listener.GetContextAsync();
                _ = Task.Run(() => HandleRequest(context));
            }
            catch (HttpListenerException)
            {
                break;
            }
            catch (ObjectDisposedException)
            {
                break;
            }
        }
    }

    private void HandleRequest(HttpListenerContext context)
    {
        if (context.Request.Url?.AbsolutePath.Equals("/fetchpackage", StringComparison.OrdinalIgnoreCase) == true)
        {
            string? indexStr = context.Request.QueryString["index"];
            if (indexStr != null && long.TryParse(indexStr, out long index))
            {
                var data = _getData(index);
                if (data != null)
                {
                    _writeResponse(data, context.Response);
                }
                else
                {
                    var responseText = JsonSerializer.Serialize(new { error = "Data not found" });
                    context.Response.StatusCode = 404;
                    byte[] buffer = Encoding.UTF8.GetBytes(responseText);
                    context.Response.ContentType = "application/json";
                    context.Response.ContentLength64 = buffer.Length;
                    context.Response.OutputStream.Write(buffer, 0, buffer.Length);
                }
            }
            else
            {
                context.Response.StatusCode = 400;
                byte[] buffer = Encoding.UTF8.GetBytes("Invalid or missing 'index' parameter.");
                context.Response.OutputStream.Write(buffer, 0, buffer.Length);
            }
        }
        else
        {
            context.Response.StatusCode = 404;
            byte[] buffer = Encoding.UTF8.GetBytes("Not Found");
            context.Response.OutputStream.Write(buffer, 0, buffer.Length);
        }
        context.Response.OutputStream.Close();
    }

    public override string ToString()
    {
        return $"HTTP: [{string.Join(", ", _listener.Prefixes)}]";
    }
}