using System.Net;
using System.Text;

public class PdfWebViewer
{
    private HttpListener? _listener;
    private const string _url = "http://localhost:8000/";

    private Thread? _serverThread;
    private bool _runServer = true;

    public async void HandleIncomingConnections()
    {
        try
        {
            Console.WriteLine("Listening for connections on {0}", _url);

            // While a user hasn't visited the `shutdown` url, keep on handling requests
            while (_runServer)
            {
                try
                {
                    if (_listener is null) return;
                    // Will wait here until we hear from a connection
                    var ctx = await _listener.GetContextAsync();

                    // Peel out the requests and response objects
                    var req = ctx.Request;
                    var resp = ctx.Response;
                    // Write the response info
                    try
                    {
                        var splitPath = req.Url!.AbsolutePath.Trim('/');
                        await using var viewerDataStream = await FileSystem.Current.OpenAppPackageFileAsync(splitPath);
                        var ext = Path.GetExtension(req.Url.AbsolutePath);
                        string contentType = ext.Trim('.') switch
                        {
                            "html" => "text/html",
                            "js" => "application/x-javascript",
                            "css" => "text/css",
                            // ReSharper disable once StringLiteralTypo
                            "bcmap" => "application/octet-stream",
                            "svg" => "image/svg+xml",
                            "png" => "image/png",
                            "json" => "application/json",
                            "jpg" => "image/jpeg",
                            "jpeg" => "image/jpeg",
                            "gif" => "image/gif",
                            _ => "text/plain"
                        };
                        bool asText = ext.Trim('.') switch
                        {
                            "html" => true,
                            "js" => true,
                            "css" => true,
                            "json" => true,
                            _ => false
                        };
                        byte[] data;
                        if (asText)
                        {
                            using var streamReader = new StreamReader(viewerDataStream);
                            var pageData = await streamReader.ReadToEndAsync();
                            data = Encoding.UTF8.GetBytes(pageData);
                            resp.ContentEncoding = Encoding.UTF8;
                        }
                        else
                        {
                            int read = 0;
                            byte[] buffer = new byte[1024];
                            var readBytes = new List<byte>();
                            while ((read = await viewerDataStream.ReadAsync(buffer, 0, buffer.Length)) > 0)
                            {
                                readBytes.AddRange(buffer.Take(read));
                            }

                            data = readBytes.ToArray();
                        }

                        resp.ContentType = contentType;
                        resp.ContentLength64 = data.LongLength;

                        // Write out to the response stream (asynchronously), then close it
                        await resp.OutputStream.WriteAsync(data);
                    }
                    catch (Exception ex)
                    {
                        Console.WriteLine($"Could not find file: {ex}");
                        resp.ContentType = "text/plain";
                        resp.StatusCode = (int)HttpStatusCode.NotFound;
                        var data = Encoding.UTF8.GetBytes(ex.ToString());
                        resp.ContentEncoding = Encoding.UTF8;
                        resp.ContentLength64 = data.LongLength;
                        await resp.OutputStream.WriteAsync(data);
                    }

                    resp.Close();
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex);
                }
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex);
        }
    }


    public void Run()
    {
        // Create an Http server and start listening for incoming connections
        _listener = new HttpListener();
        _listener.Prefixes.Add(_url);
        _listener.Start();
        _serverThread = new Thread(new ThreadStart(HandleIncomingConnections));
        _serverThread.Start();

    }

    public void Stop()
    {
        _runServer = false;
        _listener.Stop();
        try
        {
            _serverThread.Join();
        }
        catch { }
    }
}