/BlogEngine/DotNetSlave.BusinessLogic/Providers/XmlProvider/Categories.cs

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 Category

        /// </summary>

        /// <param name="category">

        /// Must be a valid Category object.

        /// </param>

        public override void DeleteCategory(Category category)

        {

            var categories = Category.Categories;

            categories.Remove(category);



            if (Category.Categories.Contains(category))

            {

                Category.Categories.Remove(category);

            }



            this.WriteToFile();

        }



        /// <summary>

        /// Fills an unsorted list of categories.

        /// </summary>

        /// <returns>

        /// A List&lt;Category&gt; of all Categories.

        /// </returns>

        public override List<Category> FillCategories()

        {

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

            if (!File.Exists(fileName))

            {

                return null;

            }



            var doc = new XmlDocument();

            doc.Load(fileName);

            var categories = new List<Category>();



            foreach (XmlNode node in doc.SelectNodes("categories/category"))

            {

                var category = new Category { Id = new Guid(node.Attributes["id"].InnerText), Title = node.InnerText };



                if (node.Attributes["description"] != null)

                {

                    category.Description = node.Attributes["description"].InnerText;

                }

                else

                {

                    category.Description = string.Empty;

                }



                if (node.Attributes["parent"] != null)

                {

                    if (String.IsNullOrEmpty(node.Attributes["parent"].InnerText))

                    {

                        category.Parent = null;

                    }

                    else

                    {

                        category.Parent = new Guid(node.Attributes["parent"].InnerText);

                    }

                }

                else

                {

                    category.Parent = null;

                }



                categories.Add(category);

                category.MarkOld();

            }



            return categories;

        }



        /// <summary>

        /// Inserts a Category

        /// </summary>

        /// <param name="category">

        /// Must be a valid Category object.

        /// </param>

        public override void InsertCategory(Category category)

        {

            var categories = Category.Categories;

            categories.Add(category);

            categories.Sort();



            this.WriteToFile();

        }



        /// <summary>

        /// Gets a Category based on a Guid

        /// </summary>

        /// <param name="id">

        /// The category's Guid.

        /// </param>

        /// <returns>

        /// A matching Category

        /// </returns>

        public override Category SelectCategory(Guid id)

        {

            var categories = Category.Categories;



            var category = categories.FirstOrDefault(cat => cat.Id == id) ?? new Category();

            category.MarkOld();

            return category;

        }



        /// <summary>

        /// Updates a Category

        /// </summary>

        /// <param name="category">

        /// Must be a valid Category object.

        /// </param>

        public override void UpdateCategory(Category category)

        {

            var categories = Category.Categories;

            categories.Remove(category);

            categories.Add(category);

            categories.Sort();



            this.WriteToFile();

        }



        #endregion



        #region Methods



        /// <summary>

        /// Saves the Categories to disk.

        /// </summary>

        private void WriteToFile()

        {

            var categories = Category.Categories;

            var fileName = string.Format("{0}categories.xml", this.Folder);



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

            {

                writer.Formatting = Formatting.Indented;

                writer.Indentation = 4;

                writer.WriteStartDocument(true);

                writer.WriteStartElement("categories");



                foreach (var cat in categories)

                {

                    writer.WriteStartElement("category");

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

                    writer.WriteAttributeString("description", cat.Description);

                    writer.WriteAttributeString("parent", cat.Parent.ToString());

                    writer.WriteValue(cat.Title);

                    writer.WriteEndElement();

                    cat.MarkOld();

                }



                writer.WriteEndElement();

            }

        }



        #endregion

    }

}