// JSON-RPC messages to transmission-daemon
// http://groups.google.com/group/jayrock/t/c74e23f257e601b1

using System;
using System.Net;
using System.Collections;
using Jayrock.Json;
using Jayrock.Json.Conversion;

static class Program
{
    static void Main()
    {
        var url = new Uri("http://192.168.0.8:9091/transmission/rpc");
        var client = new TransmissionClient(url);
        string[] torrentNames = new string[100];
        string[] torrentPercent = new string[100];
        JsonObject session = (JsonObject)client.Invoke("session-stats", null);
        JsonNumber num = (JsonNumber)session["activeTorrentCount"];
        int numTorrents = (int)num;
        Console.WriteLine("Active Torrents: " + session["activeTorrentCount"]);
        Console.WriteLine("Download Speed: " + session["downloadSpeed"] + " Bytes/s");
        Console.WriteLine("Upload Speed: " + session["uploadSpeed"] + " Bytes/s");
        var torrent = (IDictionary) client.Invoke("torrent-get", new { fields = new[] { "name", "percentDone" } }, null);
        var i=0;
        Console.WriteLine();
        Console.WriteLine("Current Torrents:");
          foreach (IDictionary torrents in (IList) torrent["torrents"]){
          Console.WriteLine();
            if (i<numTorrents)
            {
              torrentNames[i] = (string)torrents["name"];
              JsonNumber percent = (JsonNumber)torrents["percentDone"];
              double tempPercent = (double)percent;
              torrentPercent[i] = tempPercent.ToString("0%");
              Console.WriteLine(torrentNames[i] + " - " + (torrentPercent[i]));
              i++;
            }
          }
      }
}

class TransmissionClient
{
    public Uri Url { get; private set; }
    public WebClient WebClient { get; set; }
    public string SessionId { get; private set; }

    public TransmissionClient(Uri url) : this(url, null) {}

    public TransmissionClient(Uri url, WebClient wc)
    {
        if (url == null) throw new ArgumentNullException("url");
        Url = url;
        WebClient = wc;
    }

    public object Invoke(string method, object args)
    {
        return Invoke(method, args, null);
    }

    public virtual object Invoke(string method, object args, JsonNumber? tag)
    {
        if (method == null) throw new ArgumentNullException("method");

        var sessionId = SessionId;
        var wc = WebClient ?? new WebClient();
        var url = Url;

        // 2.1.  Requests
        //
        //     Requests support three keys:
        //
        //     (1) A required "method" string telling the name of the method to invoke
        //     (2) An optional "arguments" object of key/value pairs
        //     (3) An optional "tag" number used by clients to track responses.
        //         If provided by a request, the response MUST include the same tag.

        var request = new
        {
            method,
            arguments = args,
            tag,
        };

        while (true)
        {
            try
            {
                if (!string.IsNullOrEmpty(sessionId))
                    wc.Headers.Add("X-Transmission-Session-Id", sessionId);
                var requestJson = JsonConvert.ExportToString(request);
                var responseJson = wc.UploadString(url, requestJson);

                // 2.2.  Responses
                //
                //     Reponses support three keys:
                //
                //     (1) A required "result" string whose value MUST be "success" on success,
                //         or an error string on failure.
                //     (2) An optional "arguments" object of key/value pairs
                //     (3) An optional "tag" number as described in 2.1.

                var responseObject = JsonConvert.Import<JsonObject>(responseJson);

                var result = (responseObject["result"] ?? string.Empty).ToString();
                if ("error".Equals(result, StringComparison.OrdinalIgnoreCase))
                    throw new Exception("Method failed.");
                if (!"success".Equals(result, StringComparison.OrdinalIgnoreCase))
                    throw new Exception("Unexpected response result.");

                if (tag != null && tag.Value.LogicallyEquals(responseObject["tag"]))
                    throw new Exception("Missing or unexpected tag in response.");

                return responseObject["arguments"];
            }
            catch (WebException e)
            {
                // 2.3.1.  CSRF Protection
                //
                //     Most Transmission RPC servers require a X-Transmission-Session-Id
                //     header to be sent with requests, to prevent CSRF attacks.
                //
                //     When your request has the wrong id -- such as when you send your first
                //     request, or when the server expires the CSRF token -- the
                //     Transmission RPC server will return an HTTP 409 error with the
                //     right X-Transmission-Session-Id in its own headers.
                //
                //     So, the correct way to handle a 409 response is to update your
                //     X-Transmission-Session-Id and to resend the previous request.

                HttpWebResponse response;
                if (e.Status == WebExceptionStatus.ProtocolError
                    && (response = e.Response as HttpWebResponse) != null
                    && response.StatusCode == /* 409 */ HttpStatusCode.Conflict)
                {
                    sessionId = response.GetResponseHeader("X-Transmission-Session-Id");
                    if (!string.IsNullOrEmpty(sessionId))
                    {
                        SessionId = sessionId;
                        continue;
                    }
                }

                throw;
            }
        }
    }
}