using System;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using FeedCenter.Accounts;
using FeedCenter.Options;
using Realms;

namespace FeedCenter.Feeds;

public partial class FeedItem : RealmObject
{
    [PrimaryKey]
    public Guid Id { get; set; }

    public bool BeenRead { get; set; }
    public string Description { get; set; }
    public Guid FeedId { get; set; }
    public string Guid { get; set; }
    public DateTimeOffset LastFound { get; set; }
    public string Link { get; set; }
    public bool New { get; set; }
    public int Sequence { get; set; }
    public string Title { get; set; }
    public string RemoteId { get; set; }

    public static FeedItem Create()
    {
        return new FeedItem { Id = System.Guid.NewGuid() };
    }

    public override string ToString()
    {
        var title = Title;

        switch (Properties.Settings.Default.MultipleLineDisplay)
        {
            case MultipleLineDisplay.SingleLine:

                // Strip any newlines from the title
                title = NewlineRegex().Replace(title, " ");

                break;

            case MultipleLineDisplay.FirstLine:

                // Find the first newline
                var newlineIndex = title.IndexOf('\n', StringComparison.Ordinal);

                // If a newline was found return everything before it
                if (newlineIndex > -1)
                    title = title[..newlineIndex];

                break;
            case MultipleLineDisplay.Normal:
                break;
            default:
                throw new ArgumentOutOfRangeException();
        }

        title ??= string.Empty;

        // Condense multiple spaces to one space
        title = MultipleSpaceRegex().Replace(title, " ");

        // Condense tabs to one space
        title = TabRegex().Replace(title, " ");

        // If the title is blank then put in the "no title" title
        if (title.Length == 0)
            title = Properties.Resources.NoTitleText;

        return title;
    }

    public async Task MarkAsRead(FeedCenterEntities entities)
    {
        var feed = entities.Feeds.FirstOrDefault(f => f.Id == FeedId);

        entities.SaveChanges(() =>
        {
            BeenRead = true;
            New = false;
        });

        if (feed == null || feed.Account.Type == AccountType.Local)
            return;

        await AccountReaderFactory.CreateAccountReader(feed.Account).MarkFeedItemRead(RemoteId);
    }

    [GeneratedRegex("\\n")]
    private static partial Regex NewlineRegex();

    [GeneratedRegex("[ ]{2,}")]
    private static partial Regex MultipleSpaceRegex();

    [GeneratedRegex("\\t")]
    private static partial Regex TabRegex();
}