namespace BlogEngine.Core.Providers

{

    using System;

    using System.Collections.Generic;

    using System.IO;

    using System.Linq;

    using System.Text;

    using System.Xml;



    /// <summary>

    /// A storage provider for BlogEngine that uses XML files.

    ///     <remarks>

    /// To build another provider, you can just copy and modify

    ///         this one. Then add it to the web.config's BlogEngine section.

    ///     </remarks>

    /// </summary>

    public partial class XmlBlogProvider : BlogProvider

    {

        #region Public Methods



        /// <summary>

        /// Deletes a BlogRoll

        /// </summary>

        /// <param name="blogRollItem">

        /// The blog Roll Item.

        /// </param>

        public override void DeleteBlogRollItem(BlogRollItem blogRollItem)

        {

            var blogRoll = BlogRollItem.BlogRolls;

            blogRoll.Remove(blogRollItem);

            this.WriteBlogRollFile(blogRoll);

        }



        /// <summary>

        /// Fills an unsorted list of BlogRolls.

        /// </summary>

        /// <returns>

        /// A List&lt;BlogRoll&gt; of all BlogRolls

        /// </returns>

        public override List<BlogRollItem> FillBlogRoll()

        {

            var fileName = this.Folder + "blogroll.xml";

            if (!File.Exists(fileName))

            {

                return null;

            }



            var doc = new XmlDocument();

            doc.Load(fileName);

            var blogRoll = new List<BlogRollItem>();



            var largestSortIndex = -1;

            var legacyFormat = false;

            var nodes = doc.SelectNodes("blogRoll/item");

            if (nodes != null)

            {

                if (nodes.Count == 0)

                {

                    // legacy file format.

                    nodes = doc.SelectNodes("opml/body/outline");

                    legacyFormat = true;

                }



                foreach (var br in from XmlNode node in nodes

                                   select new BlogRollItem

                                       {

                                           Id = node.Attributes["id"] == null ? Guid.NewGuid() : new Guid(node.Attributes["id"].InnerText),

                                           Title = node.Attributes["title"] == null ? null : node.Attributes["title"].InnerText,

                                           Description = node.Attributes["description"] == null ? null : node.Attributes["description"].InnerText,

                                           BlogUrl = node.Attributes["htmlUrl"] == null ? null : new Uri(node.Attributes["htmlUrl"].InnerText),

                                           FeedUrl = node.Attributes["xmlUrl"] == null ? null : new Uri(node.Attributes["xmlUrl"].InnerText), 

                                           Xfn = node.Attributes["xfn"] == null ? null : node.Attributes["xfn"].InnerText,

                                           SortIndex = node.Attributes["sortIndex"] == null ? (blogRoll.Count == 0 ? 0 : largestSortIndex + 1) : int.Parse(node.Attributes["sortIndex"].InnerText)

                                       })

                {

                    if (br.SortIndex > largestSortIndex)

                    {

                        largestSortIndex = br.SortIndex;

                    }



                    blogRoll.Add(br);

                    br.MarkOld();

                }

            }



            if (legacyFormat && blogRoll.Count > 0)

            {

                // if we're upgrading from a legacy format, re-write the file to conform to the new format.

                this.WriteBlogRollFile(blogRoll);

            }



            return blogRoll;

        }



        /// <summary>

        /// Inserts a BlogRoll

        /// </summary>

        /// <param name="blogRollItem">

        /// The blog Roll Item.

        /// </param>

        public override void InsertBlogRollItem(BlogRollItem blogRollItem)

        {

            var blogRolls = BlogRollItem.BlogRolls;

            blogRolls.Add(blogRollItem);



            this.WriteBlogRollFile(blogRolls);

        }



        /// <summary>

        /// Gets a BlogRoll based on a Guid.

        /// </summary>

        /// <param name="id">

        /// The BlogRoll's Guid.

        /// </param>

        /// <returns>

        /// A matching BlogRoll

        /// </returns>

        public override BlogRollItem SelectBlogRollItem(Guid id)

        {

            var blogRoll = BlogRollItem.BlogRolls.Find(br => br.Id == id) ?? new BlogRollItem();



            blogRoll.MarkOld();

            return blogRoll;

        }



        /// <summary>

        /// Updates a BlogRoll

        /// </summary>

        /// <param name="blogRollItem">

        /// The blog Roll Item.

        /// </param>

        public override void UpdateBlogRollItem(BlogRollItem blogRollItem)

        {

            var blogRolls = BlogRollItem.BlogRolls;

            blogRolls.Remove(blogRollItem);

            blogRolls.Add(blogRollItem);

            this.WriteBlogRollFile(blogRolls);

        }



        #endregion



        #region Methods



        /// <summary>

        /// The write blog roll file.

        /// </summary>

        /// <param name="blogRollItems">

        /// The blog roll items.

        /// </param>

        private void WriteBlogRollFile(List<BlogRollItem> blogRollItems)

        {

            var fileName = this.Folder + "blogroll.xml";



            using (var writer = new XmlTextWriter(fileName, Encoding.UTF8))

            {

                writer.Formatting = Formatting.Indented;

                writer.Indentation = 4;

                writer.WriteStartDocument(true);

                writer.WriteStartElement("blogRoll");



                foreach (var br in blogRollItems)

                {

                    writer.WriteStartElement("item");

                    writer.WriteAttributeString("id", br.Id.ToString());

                    writer.WriteAttributeString("title", br.Title);

                    writer.WriteAttributeString("description", br.Description ?? string.Empty);

                    writer.WriteAttributeString("htmlUrl", br.BlogUrl != null ? br.BlogUrl.ToString() : string.Empty);

                    writer.WriteAttributeString("xmlUrl", br.FeedUrl != null ? br.FeedUrl.ToString() : string.Empty);

                    writer.WriteAttributeString("xfn", br.Xfn ?? string.Empty);

                    writer.WriteAttributeString("sortIndex", br.SortIndex.ToString());

                    writer.WriteEndElement();

                    br.MarkOld();

                }



                writer.WriteEndElement();

            }

        }



        #endregion

    }

}