ANTOOZA-BACKEND/Application/Features/Api/Auth/ResendEmail/Handler.cs

using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Application.Abstractions.Messaging.Email;
using Application.Common;
using Domain.Entities.EmailVerification;
using Domain.Entities.EmailVerification.ValueObject;
using SharedKernel.Results;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Api.Auth.ResendEmail;

internal sealed class Handler(
    IAppDbContext db,
    IMailService mailService
) : ICommandHandler<Command, Result>
{
    public async Task<Result> Handle(Command request, CancellationToken ct)
    {
        // 이메일 유효성 검사
        if (string.IsNullOrWhiteSpace(request.Email))
        {
            return Result.Failure(Error.Problem("Auth.EmailRequired", "이메일은 필수입니다."));
        }

        var email = request.Email.Trim().ToLower();

        // 회원 조회
        var member = await db.Member.FirstOrDefaultAsync(m => m.Email == email, ct);
        if (member is null)
        {
            return Result.Failure(Error.NotFound("Auth.MemberNotFound", "회원 정보를 찾을 수 없습니다."));
        }

        // 타입별 유효성 검사
        switch (request.Type)
        {
            case VerificationType.Registration:
                if (member.IsEmailVerified)
                {
                    return Result.Failure(Error.Conflict("Auth.AlreadyVerified", "이미 인증된 이메일입니다."));
                }
                break;

            case VerificationType.ForgotPassword:
                if (member.IsWithdraw)
                {
                    return Result.Failure(Error.Problem("Auth.MemberWithdrawn", "탈퇴한 회원은 이용할 수 없습니다."));
                }
                if (member.IsDenied)
                {
                    return Result.Failure(Error.Problem("Auth.MemberDenied", "차단된 회원이므로 이용할 수 없습니다."));
                }
                break;
        }

        // 기존 미인증 코드 삭제
        var existing = await db.EmailVerifyNumber.Where(e => e.Email == email && e.Type == request.Type && !e.IsVerified).ToListAsync(ct);

        db.EmailVerifyNumber.RemoveRange(existing);

        // 6자리 랜덤 숫자 코드 생성
        var code = Random.Shared.Next(100000, 999999).ToString();
        var expiration = request.Type == VerificationType.Registration ? DateTime.UtcNow.AddMinutes(5) : DateTime.UtcNow.AddMinutes(10);

        // 인증번호 생성
        var verifyNumber = EmailVerifyNumber.Create(request.Type, email, code, expiration);

        await db.EmailVerifyNumber.AddAsync(verifyNumber, ct);
        await db.SaveChangesAsync(ct);

        // 타입별 이메일 발송
        var emailTpl = (await db.Config.AsNoTracking().FirstOrDefaultAsync(ct))?.EmailTemplate;
        string subject;
        string body;
        switch (request.Type)
        {
            case VerificationType.Registration:
                subject = string.IsNullOrWhiteSpace(emailTpl?.RegisterEmailFormTitle)
                    ? "회원가입 이메일 인증번호"
                    : emailTpl!.RegisterEmailFormTitle!;
                body = string.IsNullOrWhiteSpace(emailTpl?.RegisterEmailFormContent)
                    ? $"<p>회원가입 이메일 인증번호입니다.</p><p><strong>{code}</strong></p><p>이 코드는 5분간 유효합니다.</p>"
                    : emailTpl!.RegisterEmailFormContent!.Render(("Code", code), ("Email", email));
                break;
            case VerificationType.ForgotPassword:
                subject = string.IsNullOrWhiteSpace(emailTpl?.ResetPasswordEmailFormTitle)
                    ? "비밀번호 재설정 인증번호"
                    : emailTpl!.ResetPasswordEmailFormTitle!;
                body = string.IsNullOrWhiteSpace(emailTpl?.ResetPasswordEmailFormContent)
                    ? $"<p>비밀번호 재설정 인증번호입니다.</p><p><strong>{code}</strong></p><p>이 코드는 10분간 유효합니다.</p>"
                    : emailTpl!.ResetPasswordEmailFormContent!.Render(("Code", code), ("Email", email));
                break;
            default:
                return Result.Failure(Error.Problem("Auth.UnsupportedVerificationType", $"지원하지 않는 인증 타입입니다: {request.Type}"));
        }

        await mailService.SendAsync(new SendData(email, subject, body), ct);

        return Result.Success();
    }
}