SPMS_API/SPMS.Application/Services/MessageService.cs

using SPMS.Application.DTOs.Message;
using SPMS.Application.Interfaces;
using SPMS.Domain.Common;
using SPMS.Domain.Exceptions;
using SPMS.Domain.Interfaces;

namespace SPMS.Application.Services;

public class MessageService : IMessageService
{
    private readonly IMessageRepository _messageRepository;

    public MessageService(IMessageRepository messageRepository)
    {
        _messageRepository = messageRepository;
    }

    public async Task<MessagePreviewResponseDto> PreviewAsync(long serviceId, MessagePreviewRequestDto request)
    {
        var message = await _messageRepository.GetByMessageCodeAndServiceAsync(request.MessageCode, serviceId);
        if (message == null)
            throw new SpmsException(ErrorCodes.MessageNotFound, "존재하지 않는 메시지 코드입니다.", 404);

        var title = ApplyVariables(message.Title, request.Variables);
        var body = ApplyVariables(message.Body, request.Variables);

        return new MessagePreviewResponseDto
        {
            Title = title,
            Body = body,
            ImageUrl = message.ImageUrl,
            LinkUrl = message.LinkUrl
        };
    }

    private static string ApplyVariables(string template, Dictionary<string, string>? variables)
    {
        if (variables == null || variables.Count == 0)
            return template;

        var result = template;
        foreach (var (key, value) in variables)
        {
            result = result.Replace($"{{{{{key}}}}}", value);
        }
        return result;
    }
}