using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Xml;

namespace RssBanditToOpml
{
    class Program
    {
        static void Main(string[] args)
        {
            string srcFile = null;
            string dstFile = null;

            Console.WriteLine("Convert RSS Bandit exported files to OPML format");
            Console.WriteLine("Parameters: RSSConvert \"inputfile\" \"outputfile\"");
            Console.WriteLine("");

            if (args.Length == 2)
            {
                srcFile = args[0];
                dstFile = args[1];

                if (File.Exists(srcFile))
                {
                    Console.Write("Converting...");
                    convert(srcFile, dstFile);
                    Console.WriteLine("Done");
                }
                else
                    Console.WriteLine("Source file '{0}' does not exist.", srcFile);
            }
            else
                Console.WriteLine("Parameter Error");

            Console.WriteLine("");
            Console.Write("Hit a key...");
            Console.Read();
        }

        private static void convert(string srcFile, string dstFile)
        {
            XmlTextWriter dstXml = new XmlTextWriter(dstFile, System.Text.Encoding.ASCII); // utf-8 yields a byte order mark that grazr currently chokes on

            // Write Headers
            dstXml.Formatting = Formatting.Indented;
            dstXml.WriteStartDocument();
            dstXml.WriteStartElement("opml");
            dstXml.WriteAttributeString("version", "1.1");
            dstXml.WriteStartElement("head");
            dstXml.WriteStartElement("title");
            dstXml.WriteString("RssBandit blogroll");
            dstXml.WriteEndElement();

            dstXml.WriteEndElement();
            dstXml.WriteStartElement("body");

            SortedDictionary<string, Outline> outlines = new SortedDictionary<string, Outline>();

            XmlDocument doc = new XmlDocument();
            doc.Load(srcFile);

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

            createNodes(outlines, outerOutlinenodes);

            foreach (Outline outline in outlines.Values)
            {
                outline.SerializeToXml(dstXml);
            }

            dstXml.WriteEndElement();
            dstXml.WriteEndElement();
            dstXml.WriteEndDocument();

            dstXml.Close();

        }

        private static void createNodes(SortedDictionary<string, Outline> outlines, XmlNodeList outlinenodes)
        {
            foreach (XmlNode outlinenode in outlinenodes)
            {
                string title = outlinenode.Attributes["title"].Value;
                outlines.Add(title, new Outline(title, outlinenode));
            }
        }

        class Outline
        {
            #region fields and properties
            private string title;

            public string Title
            {
                get { return title; }
                set { title = value; }
            }

            SortedDictionary<string, Outline> outlines = new SortedDictionary<string, Outline>();

            string type;
            string xmlUrl;
            #endregion

            #region ctors
            public Outline(string title, XmlNode outlinenode)
            {
                this.title = title;

                if (outlinenode.HasChildNodes)
                {
                    XmlNodeList innerOutlinenodes = outlinenode.SelectNodes("outline");
                    createNodes(outlines, innerOutlinenodes);
                }
                else
                {
                    type = "rss";
                    xmlUrl = outlinenode.Attributes["xmlUrl"].Value.ToString();
                }
            } 
            #endregion

            internal void SerializeToXml(XmlTextWriter dstXml)
            {
                dstXml.WriteStartElement("outline");
                dstXml.WriteAttributeString("text", title);

                foreach (Outline outline in outlines.Values)
                {
                    outline.SerializeToXml(dstXml);
                }

                if (type != null)
                {
                    dstXml.WriteAttributeString("type", type);
                    dstXml.WriteAttributeString("xmlUrl", xmlUrl);
                }

                dstXml.WriteEndElement();

            }
        }

    }
}