Umbraco-CMS/src/Umbraco.Core/Models/PublishedContent/VariationContextAccessorExtensions.cs

namespace Umbraco.Core.Models.PublishedContent
{
    public static class VariationContextAccessorExtensions
    {
        public static void ContextualizeVariation(this IVariationContextAccessor variationContextAccessor, ContentVariation variations, ref string culture, ref string segment)
            => variationContextAccessor.ContextualizeVariation(variations, null, ref culture, ref segment);

        public static void ContextualizeVariation(this IVariationContextAccessor variationContextAccessor, ContentVariation variations, int contentId, ref string culture, ref string segment)
            => variationContextAccessor.ContextualizeVariation(variations, (int?)contentId, ref culture, ref segment);

        private static void ContextualizeVariation(this IVariationContextAccessor variationContextAccessor, ContentVariation variations, int? contentId, ref string culture, ref string segment)
        {
            if (culture != null && segment != null) return;

            // use context values
            var publishedVariationContext = variationContextAccessor?.VariationContext;
            if (culture == null) culture = variations.VariesByCulture() ? publishedVariationContext?.Culture : "";

            if (segment == null)
            {
                if (variations.VariesBySegment())
                {
                    segment = contentId == null
                        ? publishedVariationContext?.Segment
                        : publishedVariationContext?.GetSegment(contentId.Value);
                }
                else
                {
                    segment = "";
                }
            }
        }
    }
}