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)
    {
        if (string.IsNullOrWhiteSpace(languageCode))
            throw new InvalidDataException("LanguageCode is required.");

        EmailTemplate? template = await _templateRepository.GetAsync(
            serviceName,
            templateKey,
            languageCode,
            cancellationToken);

        if (template is null)
        {
            string compatibilityCode = languageCode.Trim().ToLowerInvariant();
            if (!string.Equals(languageCode, compatibilityCode, StringComparison.Ordinal))
                template = await _templateRepository.GetAsync(serviceName, templateKey, compatibilityCode, cancellationToken);
        }

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