using System;
using System.IO;
using System.Net;
using System.Text;
using System.Xml;
using ThePlanCollectionCore.Utils;

namespace ThePlanCollectionCore.DataFeeds
{
    /// <summary>
    /// Wrapper for xml rpc service
    /// that can ping ping-o-matic and other services
    /// when your blog is updated.
    /// </summary>
    static public class Ping
    {
        // List of services that accept an xml rpc ping.
        // If you surf around the net you will find many other
        // services but many of them are offline or 
        // appear to be junk.  Stick with the main ones.
        static private string [] _Services = {
            "http://rpc.pingomatic.com",
            "http://blogsearch.google.com/ping/RPC2",
            "http://www.blogsnow.com/ping",
            "http://www.wasalive.com/ping/"
            };


        /// <summary>
        /// Sends a ping to the above services using the given website name 
        /// and url
        /// </summary>
        /// <param name="websiteName">The name of the website or blog
        /// that has been updated.</param>
        /// <param name="websiteUrl">The url of the website or blog
        /// that has been updated.  This should be an absolute root url
        /// not a direct link to the individual page that has been updated.</param>
        public static void Send(string websiteName, string websiteUrl)
        {
            for (int i = 0; i < _Services.Length; i++)
            {
                try
                {
                    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(_Services[i]);
                    request.Method = "POST";
                    request.ContentType = "text/xml";
                    request.Timeout = 3000;

                    // Add in the updated page
                    BuildRequest(request, websiteName, websiteUrl);

                    // Send off the request
                    request.GetResponse();
                }
                catch (Exception ex)
                {
                    // Log the error.
                    Error err = new Error();
                    err.Title = "Ping Request Failure";
                    err.Body = "Ping to " + _Services[i] + " failed with error: " + ex.Message;
                    err.Save();
                }
            }
        }

        /// <summary>
        /// Adds the requred xml to the request.  This includes the website name and url
        /// along with the method name 'ping' that will tell the remote servers that
        /// and update has been made
        /// </summary>
        /// <param name="request">A http webrequest generated by the method 'Send' above.</param>
        /// <param name="websiteName">The name of the website or blog
        /// that has been updated.</param>
        /// <param name="websiteUrl">The url of the website or blog
        /// that has been updated.  This should be an absolute root url
        /// not a direct link to the individual page that has been updated.</param>
        private static void BuildRequest(HttpWebRequest request, string websiteName, string websiteUrl)
        {
            Stream stream = request.GetRequestStream();
            using (XmlTextWriter writer = new XmlTextWriter(stream, Encoding.ASCII))
            {
                writer.WriteStartDocument();
                writer.WriteStartElement("methodCall");
                writer.WriteElementString("methodName", "ping");
                writer.WriteStartElement("params");
                writer.WriteStartElement("param");
                
                // Add the name of your website here
                writer.WriteElementString("value", websiteName);
                writer.WriteEndElement();
                writer.WriteStartElement("param");

                // The absolute URL of your website - not the updated or new page
                writer.WriteElementString("value", websiteUrl);
                writer.WriteEndElement();
                writer.WriteEndElement();
                writer.WriteEndElement();
            }
        }
    }
}