namespace Application.Subjects.Queries;

using Application.Subjects.DTOs;
using Domain.Ports.Repositories;
using MediatR;

public record GetSubjectsQuery : IRequest<IReadOnlyList<SubjectDto>>;

public class GetSubjectsHandler(ISubjectRepository subjectRepository)
    : IRequestHandler<GetSubjectsQuery, IReadOnlyList<SubjectDto>>
{
    public async Task<IReadOnlyList<SubjectDto>> Handle(GetSubjectsQuery request, CancellationToken ct)
    {
        // Direct projection - only SELECT needed columns
        return await subjectRepository.GetAllProjectedAsync(
            s => new SubjectDto(
                s.Id,
                s.Name,
                s.Credits,
                s.ProfessorId,
                s.Professor != null ? s.Professor.Name : ""), ct);
    }
}