MireaBackend/Application/Cqrs/LectureHall/Queries/GetLectureHallList/GetLectureHallListQueryHandler.cs

using MediatR;
using Microsoft.EntityFrameworkCore;
using Mirea.Api.DataAccess.Application.Interfaces.DbContexts.Schedule;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace Mirea.Api.DataAccess.Application.Cqrs.LectureHall.Queries.GetLectureHallList;

public class GetLectureHallListQueryHandler(ILectureHallDbContext dbContext) : IRequestHandler<GetLectureHallListQuery, LectureHallListVm>
{
    public async Task<LectureHallListVm> Handle(GetLectureHallListQuery request, CancellationToken cancellationToken)
    {
        var dtos = dbContext.LectureHalls.OrderBy(l => l.Id).Select(l => new LectureHallLookupDto()
        {
            Id = l.Id,
            Name = l.Name,
            CampusId = l.CampusId
        });

        if (request is { PageSize: not null, Page: not null })
            dtos = dtos.Skip(request.Page.Value * request.PageSize.Value).Take(request.PageSize.Value);

        var result = await dtos.ToListAsync(cancellationToken);

        return new LectureHallListVm
        {
            LectureHalls = result
        };
    }
}