using System;
using System.Windows.Forms;
using System.Net;
using System.Web;
using System.IO;

namespace Trowl
{
    // A delegate type for hooking up change notifications.
    public delegate void BeforeUrlShortenEventHandler(object sender, EventArgs e);
    public delegate void AfterUrlShortenEventHandler(object sender, EventArgs e);

    class UrlShorteningTextBox : TextBox
    {
        private const int WM_PASTE = 0x0302;

        public bool AutoShortenUrls
        {
            get;
            set;
        }

        public event BeforeUrlShortenEventHandler BeforeUrlShorten;
        public event AfterUrlShortenEventHandler AfterUrlShorten;

        protected virtual void OnBeforeShorten(EventArgs e)
        {
            if (BeforeUrlShorten != null)
                BeforeUrlShorten(this, e);
        }

        protected virtual void OnAfterShorten(EventArgs e)
        {
            if (AfterUrlShorten != null)
                AfterUrlShorten(this, e);
        }

        public UrlShorteningTextBox() : base()
        {
            this.AutoShortenUrls = true;
        }

        protected override void WndProc(ref Message m)
        {
            if (m.Msg == WM_PASTE)
            {
                if (this.AutoShortenUrls && Clipboard.ContainsText())
                {
                    String url = Clipboard.GetText();

                    if (url.StartsWith("http://") && !url.Contains(" "))
                    {
                        OnBeforeShorten(EventArgs.Empty);
                        url = ShortenUrl(url);
                        Clipboard.SetText(url);
                        OnAfterShorten(EventArgs.Empty);
                    }
                }
            }

            base.WndProc(ref m);
        }

        private string ShortenUrl(string sLongUrl)
        {
            String sShortUrl = null;
            String sRequestUrl = "http://is.gd/api.php?longurl=" + HttpUtility.UrlEncode(sLongUrl);

            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(sRequestUrl);
            request.Method = "GET";

            try
            {
                WebResponse response = request.GetResponse();
                StreamReader reader = new StreamReader(response.GetResponseStream());
                sShortUrl = reader.ReadToEnd();
                reader.Close();
                reader.Dispose();
                response.Close();
            }
            catch //(WebException e)
            {
                //throw new WebException(e.Message, e, e.Status, e.Response);
                return sLongUrl;
            }

            if (sShortUrl != null && sShortUrl.StartsWith("http://"))
            {
                return sShortUrl;
            }
            else
            {
                return sLongUrl;
            }
        }
    }
}