using System;
using System.Linq;
using System.Threading.Tasks;
using Kruzya.TelegramBot.RichSiteSummary.Data;
using Microsoft.EntityFrameworkCore;
using Telegram.Bot.Types;

namespace Kruzya.TelegramBot.RichSiteSummary;

internal static class RichSiteSummaryRepositoryExtension
{
    #region Subscriber

    /// <summary>
    /// Searchs the <see cref="Subscriber"/>, who reads a <see cref="Feed"/>.
    /// </summary>
    /// <param name="repository"></param>
    /// <param name="feed"></param>
    /// <returns>The array with all subscribers.</returns>
    public static async Task<Subscriber[]> ByFeed(this DbSet<Subscriber> repository, Feed feed)
    {
        return await repository.Where(subscriber => subscriber.Feed == feed)
            .ToArrayAsync();
    }

    public static IQueryable<Subscriber> AllSubscriptions(this DbSet<Subscriber> repository, Chat chat)
    {
        return repository.Where(entity => entity.SubscriberId == chat.Id);
    }

    public static async Task<bool> HasSubscription(this DbSet<Subscriber> repository, Chat chat, Feed feed)
    {
        return (await repository.Where(subscriber => subscriber.Feed == feed && subscriber.SubscriberId == chat.Id)
            .CountAsync()) != 0;
    }

    #endregion
        
    #region Feed

    /// <summary>
    /// Searchs the <see cref="Feed"/> for fetching.
    /// </summary>
    /// <param name="repository"></param>
    /// <param name="period">The period (in seconds) from last fetching.</param>
    /// <param name="count">Max results count</param>
    /// <returns></returns>
    public static async Task<Feed[]> ForFetching(this DbSet<Feed> repository, UInt16 period, UInt16 count) =>
        await repository.Where(feed => feed.UpdatedAt < (DateTime.Now - TimeSpan.FromSeconds(period)))
            .OrderBy(feed => feed.UpdatedAt)
            .Take(count)
            .ToArrayAsync();

    /// <summary>
    /// Searchs the <see cref="Feed"/> for fetching.
    /// </summary>
    /// <param name="repository"></param>
    /// <param name="period">The period (in seconds) from last fetching.</param>
    /// <returns></returns>
    public static async Task<Feed[]> ForFetching(this DbSet<Feed> repository, UInt16 period) =>
        await repository.ForFetching(period, 25);

    #endregion
        
    #region Post

    public static async Task<Post> ByFeedAndUrl(this DbSet<Post> repository, string url, Feed feed = null) =>
        await repository.FirstOrDefaultAsync(post => post.Url == url && (feed == null || post.Feed == feed));

    #endregion
}