hrynco-notification-service/HrynCo.NotificationService.Services/EmailTemplates/Delete/DeleteEmailTemplateHandler.cs

using HrynCo.NotificationService.DAL.Abstract.Templates;
using HrynCo.DAL.Abstract;
using HrynCo.NotificationService.DAL.Abstract.Repositories;
using HrynCo.NotificationService.Services.Core;
using HrynCo.NotificationService.Services.Logging;
using static HrynCo.NotificationService.Services.Core.ServiceResultHelper;

namespace HrynCo.NotificationService.Services.EmailTemplates.Delete;

internal sealed class DeleteEmailTemplateHandler
    : RequestHandler<DeleteEmailTemplateCommand, ServiceResult<Unit>>
{
    private readonly IEmailTemplateRepository _templates;

    public DeleteEmailTemplateHandler(
        IContextualSerilogLogger<DeleteEmailTemplateCommand> logger,
        IEmailTemplateRepository templates)
        : base(logger)
    {
        _templates = templates;
    }

    protected override async Task<ServiceResult<Unit>> DoOnHandle(
        DeleteEmailTemplateCommand request, CancellationToken cancellationToken)
    {
        var template = await _templates.GetAsync(
            request.ServiceName, request.Key, request.LanguageCode, cancellationToken);

        if (template is null)
            return Failure<Unit>("Template not found.", ServiceErrorCode.NotFound);
        if (request.ExpectedVersionId is Guid expectedId && template.Id != expectedId)
            return Failure<Unit>("Template changed after you opened it. Reload before deleting.", ServiceErrorCode.Conflict);

        try
        {
            await _templates.DeleteAsync(template, cancellationToken);
        }
        catch (EmailTemplateWriteException error)
        {
            return Failure<Unit>(error.Message, error.IsConflict ? ServiceErrorCode.Conflict : ServiceErrorCode.InvalidRequest);
        }

        return Success(Unit.Value);
    }
}