namespace HrynCo.NotificationService.Worker.Services.EmailProcessing;

using HrynCo.NotificationService.DAL.Abstract.Repositories;
using HrynCo.NotificationService.DAL.Abstract.Templates;

internal sealed class EmailTemplateService : IEmailTemplateService
{
    private readonly IEmailTemplateRepository _templateRepository;

    public EmailTemplateService(IEmailTemplateRepository templateRepository)
    {
        _templateRepository = templateRepository;
    }

    public async Task<EmailTemplate> GetAsync(
        string serviceName,
        string templateKey,
        string? languageCode,
        CancellationToken cancellationToken)
    {
        var lang = string.IsNullOrWhiteSpace(languageCode) ? "en" : languageCode;
        var template = await _templateRepository.GetAsync(serviceName, templateKey, lang, cancellationToken);

        if (template is null && lang != "en")
            template = await _templateRepository.GetAsync(serviceName, templateKey, "en", cancellationToken);

        return template
            ?? throw new InvalidOperationException(
                $"Template not found: service='{serviceName}' key='{templateKey}' language='{lang}'.");
    }
}