/BlogEngine/DotNetSlave.BusinessLogic/Web/HttpHandlers/Apml.cs

namespace BlogEngine.Core.Web.HttpHandlers

{

    using System;

    using System.Collections.Generic;

    using System.IO;

    using System.Linq;

    using System.Text;

    using System.Web;

    using System.Xml;



    /// <summary>

    /// Based on John Dyer's (http://johndyer.name/) extension.

    /// </summary>

    public class Apml : IHttpHandler

    {

        #region Properties



        /// <summary>

        ///     Gets a value indicating whether another request can use the <see cref = "T:System.Web.IHttpHandler"></see> instance.

        /// </summary>

        /// <value></value>

        /// <returns>true if the <see cref = "T:System.Web.IHttpHandler"></see> instance is reusable; otherwise, false.</returns>

        public bool IsReusable

        {

            get

            {

                return false;

            }

        }



        #endregion



        #region Implemented Interfaces



        #region IHttpHandler



        /// <summary>

        /// Enables processing of HTTP Web requests by a custom HttpHandler that implements the <see cref="T:System.Web.IHttpHandler"></see> interface.

        /// </summary>

        /// <param name="context">

        /// An <see cref="T:System.Web.HttpContext"></see> object that provides references to the intrinsic server objects (for example, Request, Response, Session, and Server) used to service HTTP requests.

        /// </param>

        public void ProcessRequest(HttpContext context)

        {

            context.Response.ContentType = "text/xml";

            WriteApmlDocument(context.Response.OutputStream);

        }



        #endregion



        #endregion



        #region Methods



        /// <summary>

        /// Finds the max.

        /// </summary>

        /// <param name="dic">The dictionary.</param>

        /// <returns>A list of Concept.</returns>

        private static IEnumerable<Concept> FindMax(Dictionary<string, Concept> dic)

        {

            float max = 0;

            float max1 = max;

            foreach (var concept in dic.Values.Where(concept => concept.Score > max1))

            {

                max = concept.Score;

            }



            // reset values as a percentage of the max

            var list = dic.Keys.Select(key => new Concept(dic[key].LastUpdated, dic[key].Score / max, key)).ToList();



            list.Sort((c1, c2) => c2.Score.CompareTo(c1.Score));



            return list;

        }



        /// <summary>

        /// Closes the writer.

        /// </summary>

        /// <param name="xmlWriter">The XML writer.</param>

        private static void CloseWriter(XmlWriter xmlWriter)

        {

            xmlWriter.WriteEndElement(); // APML

            xmlWriter.WriteEndDocument();

            xmlWriter.Close();

        }



        //// modified version of what's happening in the tag cloud

        // private Dictionary<string, Concept> CreateCategoryList()

        // {

        // // get all the tags and count the number of usages

        // Dictionary<string, Concept> dic = new Dictionary<string, Concept>();

        // foreach (Post post in Post.Posts)

        // {

        // if (post.Visible)

        // {

        // foreach (Category cat in post.Categories)

        // {

        // if (dic.ContainsKey(cat.Title))

        // {

        // Concept concept = dic[cat.Title];

        // concept.Score++;

        // if (post.DateModified > concept.LastUpdated)

        // concept.LastUpdated = post.DateModified;

        // dic[cat.Title] = concept;

        // }

        // else

        // {

        // dic[cat.Title] = new Concept(post.DateModified, 1);

        // }

        // }

        // }

        // }



        // return FindMax(dic);

        // }



        /// <summary>

        /// Creates the link list.

        /// </summary>

        /// <returns>A dictionary of string, string.</returns>

        private static Dictionary<string, string> CreateLinkList()

        {

            var dic = new Dictionary<string, string>();



            foreach (var br in BlogRollItem.BlogRolls)

            {

                var title = br.Title;

                var website = br.BlogUrl.ToString();

                dic.Add(title, website);

            }



            return dic;

        }



        /// <summary>

        /// Creates the tag list.

        /// </summary>

        /// <returns>A list of concepts.</returns>

        private static IEnumerable<Concept> CreateTagList()

        {

            // get all the tags and count the number of usages

            var dic = new Dictionary<string, Concept>();

            foreach (var post in Post.Posts)

            {

                if (!post.IsVisible)

                {

                    continue;

                }



                foreach (var tag in post.Tags)

                {

                    if (dic.ContainsKey(tag))

                    {

                        var concept = dic[tag];

                        concept.Score++;

                        if (post.DateModified > concept.LastUpdated)

                        {

                            concept.LastUpdated = post.DateModified;

                        }



                        dic[tag] = concept;

                    }

                    else

                    {

                        dic[tag] = new Concept(post.DateModified, 1, tag);

                    }

                }

            }



            return FindMax(dic);

        }



        /// <summary>

        /// Gets the writer.

        /// </summary>

        /// <param name="stream">The stream.</param>

        /// <returns>An xml writer.</returns>

        private static XmlWriter GetWriter(Stream stream)

        {

            var settings = new XmlWriterSettings { Encoding = Encoding.UTF8, Indent = true };

            var xmlWriter = XmlWriter.Create(stream, settings);



            xmlWriter.WriteStartDocument();

            xmlWriter.WriteStartElement("APML");



            return xmlWriter;

        }



        /// <summary>

        /// The write apml document.

        /// </summary>

        /// <param name="stream">

        /// The stream.

        /// </param>

        private static void WriteApmlDocument(Stream stream)

        {

            var writer = GetWriter(stream);



            // HEAD

            writer.WriteStartElement("Head");

            writer.WriteElementString(

                "Title", "APML data for " + BlogSettings.Instance.Name + " - " + BlogSettings.Instance.Description);

            writer.WriteElementString("Generator", "BlogEngine.NET " + BlogSettings.Instance.Version());

            writer.WriteElementString("UserEmail", string.Empty);

            writer.WriteElementString("DateCreated", DateTime.Now.ToString());

            writer.WriteEndElement(); // Head



            // BODY

            writer.WriteStartElement("Body");

            writer.WriteAttributeString("defaultProfile", "tags");



            // tags

            writer.WriteStartElement("Profile");

            writer.WriteAttributeString("name", "tags");

            writer.WriteStartElement("ImplicitData");

            writer.WriteStartElement("Concepts");



            var tagList = CreateTagList();

            foreach (var key in tagList)

            {

                writer.WriteStartElement("Concept");

                writer.WriteAttributeString("key", key.Title);

                writer.WriteAttributeString("value", key.Score.ToString());

                writer.WriteAttributeString("from", Utils.AbsoluteWebRoot.ToString());

                writer.WriteAttributeString("updated", key.LastUpdated.ToString());

                writer.WriteEndElement(); // Concept

            }



            writer.WriteEndElement(); // Concepts

            writer.WriteEndElement(); // ImplicitData

            writer.WriteEndElement(); // Profile



            // categories

            // writer.WriteStartElement("Profile");

            // writer.WriteAttributeString("name", "categories");

            // writer.WriteStartElement("ImplicitData");

            // writer.WriteStartElement("Concepts");



            // Dictionary<string, Concept> catList = CreateCategoryList();

            // foreach (string key in catList.Keys)

            // {

            // writer.WriteStartElement("Concept");

            // writer.WriteAttributeString("key", key);

            // writer.WriteAttributeString("value", catList[key].Score.ToString());

            // writer.WriteAttributeString("from", Utils.AbsoluteWebRoot.ToString());

            // writer.WriteAttributeString("updated", catList[key].LastUpdated.ToString());

            // writer.WriteEndElement();  // Concept

            // }



            // writer.WriteEndElement();  // Concepts

            // writer.WriteEndElement();  // ImplicitData

            // writer.WriteEndElement();  // Profile



            // links

            writer.WriteStartElement("Profile");

            writer.WriteAttributeString("name", "links");

            writer.WriteStartElement("ExplicitData");

            writer.WriteStartElement("Concepts");



            var links = CreateLinkList();

            if (links != null)

            {

                foreach (var title in links.Keys)

                {

                    var website = links[title];

                    writer.WriteStartElement("Source");

                    writer.WriteAttributeString("key", website);

                    writer.WriteAttributeString("name", title);

                    writer.WriteAttributeString("value", "1.0");

                    writer.WriteAttributeString("type", "text/html");

                    writer.WriteAttributeString("from", Utils.AbsoluteWebRoot.ToString());

                    writer.WriteAttributeString("updated", DateTime.Now.ToString());



                    writer.WriteStartElement("Author");

                    writer.WriteAttributeString("key", title);

                    writer.WriteAttributeString("value", "1.0");

                    writer.WriteAttributeString("from", Utils.AbsoluteWebRoot.ToString());

                    writer.WriteAttributeString("updated", DateTime.Now.ToString());

                    writer.WriteEndElement(); // Author



                    writer.WriteEndElement(); // Source

                }

            }



            writer.WriteEndElement(); // Concepts

            writer.WriteEndElement(); // ImplicitData

            writer.WriteEndElement(); // Profile

            writer.WriteEndElement(); // Body



            CloseWriter(writer);

        }



        #endregion



        /// <summary>

        /// The concept.

        /// </summary>

        private class Concept

        {

            #region Constructors and Destructors



            /// <summary>

            /// Initializes a new instance of the <see cref="Concept"/> class.

            /// </summary>

            /// <param name="lastUpdated">

            /// The last updated.

            /// </param>

            /// <param name="score">

            /// The score.

            /// </param>

            /// <param name="title">

            /// The title.

            /// </param>

            public Concept(DateTime lastUpdated, float score, string title)

            {

                this.LastUpdated = lastUpdated;

                this.Score = score;

                this.Title = title;

            }



            #endregion



            #region Properties



            /// <summary>

            ///     Gets or sets the last updated.

            /// </summary>

            /// <value>The last updated.</value>

            public DateTime LastUpdated { get; set; }



            /// <summary>

            ///     Gets or sets the score.

            /// </summary>

            /// <value>The score.</value>

            public float Score { get; set; }



            /// <summary>

            ///     Gets the title.

            /// </summary>

            /// <value>The title.</value>

            public string Title { get; private set; }



            #endregion

        }

    }

}