FeedCenter/Application/MainWindow/FeedCreation.cs

using System;
using System.Linq;
using System.Net;
using Common.Internet;
using FeedCenter.Options;

namespace FeedCenter
{
    public partial class MainWindow
    {
        private delegate void NewFeedDelegate(string feedUrl);
        private void HandleNewFeed(string feedUrl)
        {
            // Create and configure the new feed
            var feed = Feed.Create(_database);
            feed.Source = feedUrl;
            feed.Category = _database.DefaultCategory;

            // Try to detect the feed type
            var feedTypeResult = feed.DetectFeedType();

            // If we can't figure it out it could be an HTML page
            if (feedTypeResult.Item1 == FeedType.Unknown)
            {
                // Only check if the feed was able to be read - otherwise fall through and show the dialog
                if (feedTypeResult.Item2.Length > 0)
                {
                    // Create and load an HTML document with the text
                    var htmlDocument = new HtmlAgilityPack.HtmlDocument();
                    htmlDocument.LoadHtml(feedTypeResult.Item2);

                    // Look for all RSS or atom links in the document
                    var rssLinks = htmlDocument.DocumentNode.Descendants("link")
                        .Where(n => n.Attributes["type"] != null && (n.Attributes["type"].Value == "application/rss+xml" || n.Attributes["type"].Value == "application/atom+xml"))
                        .Select(n => new Tuple<string, string>(UrlHelper.GetAbsoluteUrlString(feed.Source, n.Attributes["href"].Value), WebUtility.HtmlDecode(n.Attributes["title"]?.Value ?? string.Empty)))
                        .ToList();

                    // If there was only one link found then switch to feed to it
                    if (rssLinks.Count == 1)
                    {
                        feed.Source = rssLinks[0].Item1;
                    }
                    else
                    {
                        var feedChooserWindow = new FeedChooserWindow();
                        var feedLink = feedChooserWindow.Display(this, rssLinks);

                        if (string.IsNullOrEmpty(feedLink))
                            return;

                        feed.Source = feedLink;
                    }
                }
            }

            // Read the feed for the first time
            var feedReadResult = feed.Read(_database);

            // See if we read the feed okay
            if (feedReadResult == FeedReadResult.Success)
            {
                // Update the feed name to be the title
                feed.Name = feed.Title;

                // Add the feed to the feed table
                _database.Feeds.Add(feed);

                // Save the changes
                _database.SaveChanges();

                // Show a tip
                NotificationIcon.ShowBalloonTip(string.Format(Properties.Resources.FeedAddedNotification, feed.Name), System.Windows.Forms.ToolTipIcon.Info);

                // Re-initialize the feed display
                DisplayFeed();
            }
            else
            {
                // Feed read failed - ceate a new feed window
                var feedForm = new FeedWindow();

                var dialogResult = feedForm.Display(_database, feed, this);

                // Display the new feed form
                if (dialogResult.HasValue && dialogResult.Value)
                {
                    // Add the feed to the feed table
                    _database.Feeds.Add(feed);

                    // Save the changes
                    _database.SaveChanges();

                    // Re-initialize the feed display
                    DisplayFeed();
                }
            }
        }
    }
}