bitforum-backend/Application/Features/Auth/Register/Handler.cs

using SharedKernel.Results;
using Application.Abstractions.Data;
using MediatR;
using Microsoft.EntityFrameworkCore;
using MemberEntity = Domain.Entities.Members.Member;

namespace Application.Features.Auth.Register;

internal sealed class Handler(
    IAppDbContext db
) : IRequestHandler<Command, Result<int>> {

    public async Task<Result<int>> Handle(Command request, CancellationToken ct)
    {
        // 유효성 검사
        if (string.IsNullOrWhiteSpace(request.Email))
        {
            return Result.Failure<int>(Error.Problem("Auth.EmailRequired", "이메일은 필수입니다."));
        }

        if (string.IsNullOrWhiteSpace(request.Password))
        {
            return Result.Failure<int>(Error.Problem("Auth.PasswordRequired", "비밀번호는 필수입니다."));
        }

        if (request.Password.Length < 6)
        {
            return Result.Failure<int>(Error.Problem("Auth.PasswordTooShort", "비밀번호는 6자 이상이어야 합니다."));
        }

        // 이메일 중복 체크
        var email = request.Email.Trim().ToLower();
        var exists = await db.Member.AnyAsync(m => m.Email == email, ct);

        if (exists)
        {
            return Result.Failure<int>(Error.Conflict("Auth.EmailExists", "이미 사용 중인 이메일입니다."));
        }

        // Member 생성 (비밀번호 해싱 포함)
        var member = MemberEntity.Create(request.Email.Trim().ToLower(), request.Password);

        await db.Member.AddAsync(member, ct);
        await db.SaveChangesAsync(ct);

        return Result.Success(member.ID);
    }
}