NewPresence/data/Repository/SQLPresenceRepository.cs

using data.RemoteData.RemoteDataBase;
using data.RemoteData.RemoteDatabase.DAO;
using Microsoft.EntityFrameworkCore.Storage;

namespace data.Repository;

public class SQLPresenceRepository : IPresenceRepository
{
    private readonly RemoteDatabaseContext _context;

    public SQLPresenceRepository(RemoteDatabaseContext context)
    {
        _context = context;
    }

    public DateOnly? GetLastDateByGroupId(int groupId)
    {
        var lastDate = _context.Presences
            .Where(p => p.GroupId == groupId)
            .OrderByDescending(p => p.Date)
            .Select(p => p.Date)
            .FirstOrDefault();

        return lastDate == default ? (DateOnly?)null : lastDate;
    }

    public void SavePresence(List<PresenceDAO> presences)
    {
        foreach (var presence in presences)
        {
            _context.Presences.Add(presence);
        }
        _context.SaveChanges();
    }

    public List<PresenceDAO> ShowPresenceForDateAndGroup(DateOnly date, int groupId)
    {
        return _context.Presences.Where(p => p.GroupId == groupId && p.Date == date)
            .Join(_context.Users,
                presence=>presence.UserId,
                user=>user.UserId,
                (presence, user) => new PresenceDAO
                {
                    PresenceId = presence.PresenceId,
                    UserId = user.UserId,
                    GroupId = presence.GroupId,
                    Date = presence.Date,
                    LessonNumber = presence.LessonNumber,
                    IsAttendance = presence.IsAttendance
                }).ToList();
    }

    public List<PresenceDAO> GetForAbsent(DateOnly date, int groupId)
    {
        return _context.Presences.Where(p => p.GroupId == groupId && p.Date == date).ToList();
    }
}