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

namespace Mirea.Api.DataAccess.Application.Cqrs.Group.Commands.CreateGroup;

public class CreateGroupCommandHandler(IGroupDbContext dbContext) : IRequestHandler<CreateGroupCommand, int>
{
    public async Task<int> Handle(CreateGroupCommand request, CancellationToken cancellationToken)
    {
        var entity = await dbContext.Groups.FirstOrDefaultAsync(g => g.Name == request.Name, cancellationToken: cancellationToken);

        if (entity != null)
            throw new RecordExistException(typeof(Domain.Schedule.Group), nameof(Domain.Schedule.Group.Name), entity.Id);

        var group = new Domain.Schedule.Group()
        {
            Name = request.Name,
            FacultyId = request.FacultyId
        };

        var result = await dbContext.Groups.AddAsync(group, cancellationToken);
        await dbContext.SaveChangesAsync(cancellationToken);

        return result.Entity.Id;
    }
}