NicoNicoMyListParser.cs

using System.Net;
using System.Text.RegularExpressions;
using HtmlAgilityPack;
using NLog;
using Rss;
using VocaDb.Model.DataContracts.SongImport;
using VocaDb.Model.Domain.PVs;
using VocaDb.Model.Service.VideoServices;
using VocaDb.Model.Utils;

namespace VocaDb.Model.Service.SongImport;

public class NicoNicoMyListParser : ISongListImporter
{
	private static readonly Logger s_log = LogManager.GetCurrentClassLogger();
	private static readonly Regex s_wvrIdRegex = new(@"#(\d{3})");

	private static readonly Regex[] s_linkMatchers = new[]
	{
		new Regex(@"www.nicovideo.jp/user/\d+/mylist/\d+"),
		new Regex(@"www.nicovideo.jp/mylist/\d+"),
	};

	public Task<PartialImportedSongs> GetSongsAsync(string url, string nextPageToken, int maxResults, bool parseAll)
	{
		throw new NotSupportedException();
	}

	private bool IsRankingsItem(RssItem item)
	{
		var node = HtmlNode.CreateNode($"<div>{item.Description}</div>");
		return node.InnerText.Any() && char.IsDigit(node.InnerText, 0);
	}

	public Task<ImportedSongListContract> ParseAsync(string url, bool parseAll)
	{
		if (string.IsNullOrEmpty(url))
			throw new UnableToImportException("Feed URL cannot be empty");

		if (!url.Contains("rss="))
			url += "?rss=2.0";

		RssFeed feed;

		HttpWebRequest request = HttpWebRequest.CreateHttp(url);
		request.AllowAutoRedirect = true;
		request.UserAgent = AppConfig.UserAgent;

		try
		{
			feed = RssFeed.Read(request);
		}
		catch (UriFormatException x)
		{
			s_log.Warn(x, "Unable to parse URL");
			throw new UnableToImportException("Unable to parse URL", x);
		}
		catch (WebException x)
		{
			s_log.Error(x, "Unable to parse feed");
			throw new UnableToImportException("Unable to parse feed", x);
		}

		if (feed.Exceptions.LastException != null)
		{
			s_log.Error(feed.Exceptions.LastException, "Unable to parse feed");
			throw new UnableToImportException("Unable to parse feed", feed.Exceptions.LastException);
		}

		var result = new ImportedSongListContract();
		var channel = feed.Channels[0];
		result.Name = channel.Title;
		var wvrIdMatch = s_wvrIdRegex.Match(result.Name);

		if (wvrIdMatch.Success)
			result.WVRNumber = int.Parse(wvrIdMatch.Groups[1].Value);

		var songs = new List<ImportedSongInListContract>();
		var order = 1;

		foreach (var item in channel.Items.Cast<RssItem>())
		{
			if (parseAll || IsRankingsItem(item))
			{
				var nicoId = VideoService.NicoNicoDouga.GetIdByUrl(item.Link.ToString());
				songs.Add(new ImportedSongInListContract(PVService.NicoNicoDouga, nicoId)
				{
					SortIndex = order,
					Name = item.Title,
					Url = item.Link.ToString()
				});
				++order;
			}
		}

		result.Songs = new PartialImportedSongs(songs.ToArray(), songs.Count, null);
		return Task.FromResult(result);
	}

	public bool MatchUrl(string url) => s_linkMatchers.Any(linkMatcher => linkMatcher.IsMatch(url));
}