#region Usings



using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Xml.Linq;

using FeedReader.Data;

using FeedReader.Enums;



#endregion



namespace FeedReader.Xml

{

    internal static class FeedRdfXmlParser

    {

        private static string _cacheFolder;

        private static bool _useCache;



        internal static bool TryParse(XDocument xmlFeed, ref Feed feed, string cacheFolder, bool downloadImages, List<FeedItemFilter> itemFilters)

        {

            _cacheFolder = cacheFolder;

            _useCache = true;

            return TryParse(xmlFeed, ref feed, downloadImages, itemFilters);

        }



        internal static bool TryParse(XDocument xmlFeed, ref Feed feed, bool downloadImages, List<FeedItemFilter> itemFilters)

        {

            Feed rFeed = feed;

            XNamespace rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#";

            XElement element = xmlFeed.Element(rdf + "RDF");



            if (element != null)

            {

                LogEvents.InvokeOnDebug(new FeedArgs("The feed is a RDF feed. Now parsing the xml data"));

                XNamespace dc = "http://purl.org/dc/elements/1.1/";

                XNamespace d = "http://purl.org/rss/1.0/";

                XNamespace nsContent = "http://purl.org/rss/1.0/modules/content/";

                XNamespace nsImage = "http://purl.org/rss/1.0/modules/image/";





                rFeed.ImagePath =

                    FeedXmlParser.ParseString(

                        xmlFeed.Descendants(d + "channel").Elements(d + "image").Attributes("resource"), "channel/image/attribute[resource]");

                rFeed.Description =

                    Utils.Clean(FeedXmlParser.ParseString(xmlFeed.Descendants(d + "channel").Elements(d + "description"), "channel/description"));

                rFeed.Title =

                    Utils.Clean(FeedXmlParser.ParseString(xmlFeed.Descendants(d + "channel").Elements(d + "title"), "channel/title"));



                try

                {

                    FeedItem feedItem;

                    int i = 1;

                    foreach (XElement item in xmlFeed.Descendants(d + "item"))

                    {

                        feedItem = new FeedItem();

                        feedItem.Author = Utils.Clean(FeedXmlParser.ParseString(item.Element(d + "author"), "item[" + i + "]/author"));

                        feedItem.Title = Utils.Clean(FeedXmlParser.ParseString(item.Element(d + "title"), "item[" + i + "]/title"), true, false, true, true, itemFilters);

                        feedItem.Url = FeedXmlParser.ParseString(item.Element(d + "link"), "item[" + i + "]/link").Trim();

                        feedItem.PublishDate = FeedXmlParser.ParseDateTime(item.Element(dc + "date"), "item[" + i + "]/date");



                        LogEvents.InvokeOnDebug(new FeedArgs("Try to get feed[" + rFeed.Title + "][" + feedItem.Title + "][" + i + "] item image..."));

                        feedItem.ImagePath = FeedXmlParser.ParseString(item.Element(nsImage + "item"), d + "about", "item[" + i + "]/attribute[about]");

                        if (Path.GetExtension(feedItem.ImagePath) == ".gif" || Path.GetExtension(feedItem.ImagePath) == ".bmp" ||

                            Path.GetExtension(feedItem.ImagePath) == ".jpg" || Path.GetExtension(feedItem.ImagePath) == ".png" ||

                            Path.GetExtension(feedItem.ImagePath) == ".jpeg")

                        {

                            LogEvents.InvokeOnDebug(new FeedArgs("Enclosure of feed[" + rFeed.Title + "][" + feedItem.Title + "][" + i + "] item is an image. Parse image url..."));

                        }

                        else

                        {

                            LogEvents.InvokeOnDebug(new FeedArgs("Enclosure of feed[" + rFeed.Title + "][" + feedItem.Title + "][" + i + "] item is not an image. Skipping parsing image url..."));

                            feedItem.ImagePath = string.Empty;

                        }

                        string description = FeedXmlParser.ParseString(item.Element(d + "description"), "item[" + i + "]/description");

                        description = Utils.Clean(description, false, true, true, false, itemFilters);

                        if (string.IsNullOrEmpty(feedItem.ImagePath))

                        {

                            LogEvents.InvokeOnDebug(new FeedArgs("Try to get feed[" + rFeed.Title + "][" + feedItem.Title + "][" + i + "] image out of description field..."));

                            feedItem.ImagePath = Utils.GetImageOutOfDescription(description);

                        }

                        feedItem.Description = Utils.Clean(description, false, true, false, true, itemFilters) == "" ?

                                               Utils.Clean(Utils.GetCdata(FeedXmlParser.ParseString(item.Element(nsContent + "encoded"), "item[" + i + "]/encoded")), false, true, false, true, itemFilters) :

                                               Utils.Clean(description, false, true, false, true, itemFilters);

                        rFeed.Items.Add(feedItem);

                        i++;

                    }

                    /* rFeed.Items = (from item in xmlFeed.Descendants(d + "item")

                                   select new FeedItem

                                              {

                                                  Author = FeedXmlParser.ParseString(item.Element(d + "author"), "item/author"),

                                                  Title =

                                                      Utils.Clean(FeedXmlParser.ParseString(item.Element(d + "title"), "item/title")),

                                                  UrlPath = FeedXmlParser.ParseString(item.Element(d + "link"), "item/link"),

                                                  PublishDate = FeedXmlParser.ParseDateTime(item.Element(dc + "date"), "item/date"),

                                                  Description = Utils.Clean(FeedXmlParser.ParseString(item.Element(d + "description"), "item/description")) == "" ?

                                                              Utils.Clean(Utils.GetCdata(FeedXmlParser.ParseString(item.Element(nsContent + "encoded"), "item/encoded"))):

                                                              Utils.Clean(FeedXmlParser.ParseString(item.Element(d + "description"), "item/description")),

                                                  ImagePath = FeedXmlParser.ParseString(item.Element(nsImage + "item"), d + "about", "item/attribute[about]"),

                                              }).OrderByDescending(feedItem => feedItem.PublishDate).ToList();*/

                    

                    if (downloadImages)

                    {

                        LogEvents.InvokeOnInfo(new FeedArgs("Try to get feed images either from cache or from download links"));

                        feed = _useCache ? Utils.DownloadImages(rFeed, _cacheFolder) : Utils.DownloadImages(rFeed);

                    }

                    else feed = rFeed;

                    feed.Items = feed.Items.OrderByDescending(fItem => fItem.PublishDate).ToList();

                    LogEvents.InvokeOnDebug(new FeedArgs("Parsing of RDF feed done. See above for possibly errors or warnings"));

                    return true;

                }

                catch (Exception ex)

                {

                    LogEvents.InvokeOnError(new FeedArgs("Error parsing RDF feed", ex.Message, ex.StackTrace));

                    //feed = null;

                    return false;

                }

            }

            LogEvents.InvokeOnDebug(new FeedArgs("This is not a RDF feed or the downloaded xml file is not a valid feed"));

            //feed = null;

            return false;

        }

    }

}