EnvelopeGenerator/EnvelopeGenerator.Application/EmailTemplates/Queries/ReadEmailTemplateQuery.cs

using AutoMapper;
using MediatR;
using EnvelopeGenerator.Application.Common.Dto;
using DigitalData.Core.Abstraction.Application.Repository;
using EnvelopeGenerator.Domain.Entities;
using Microsoft.EntityFrameworkCore;

namespace EnvelopeGenerator.Application.EmailTemplates.Queries.Read;

/// <summary>
/// Stellt eine Abfrage dar, um eine E-Mail-Vorlage zu lesen.
/// Diese Klasse erbt von <see cref="EmailTemplateQueryBase"/>.
/// </summary>
public record ReadEmailTemplateQuery : EmailTemplateQueryBase, IRequest<EmailTemplateDto?>
{
}

/// <summary>
/// 
/// </summary>
public class ReadEmailTemplateQueryHandler : IRequestHandler<ReadEmailTemplateQuery, EmailTemplateDto?>
{
    private readonly IMapper _mapper;

    private readonly IRepository<EmailTemplate> _repo;

    /// <summary>
    /// Initialisiert eine neue Instanz der <see cref="EmailTemplateController"/>-Klasse.
    /// </summary>
    /// <param name="mapper">
    /// <param name="repo">
    /// Die AutoMapper-Instanz, die zum Zuordnen von Objekten verwendet wird.
    /// </param>
    public ReadEmailTemplateQueryHandler(IMapper mapper, IRepository<EmailTemplate> repo)
    {
        _mapper = mapper;
        _repo = repo;
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="request"></param>
    /// <param name="cancel"></param>
    /// <returns></returns>
    /// <exception cref="InvalidOperationException"></exception>
    public async Task<EmailTemplateDto?> Handle(ReadEmailTemplateQuery request, CancellationToken cancel)
    {
        var query = request.Id is int id
            ? _repo.Query.Where(temp => temp.Id == id)
            : _repo.Query.Where(temp => temp.Name == request.Type!.ToString());

        return _mapper.Map<EmailTemplateDto>(await query.FirstOrDefaultAsync(cancel));
    }
}