using System.Threading.Tasks;
using System.Windows;
using System.Windows.Media.Imaging;

namespace BackgroundBuilder.Services
{
    public interface IImageService
    {
        /// <summary>
        /// Loads an image from disk.
        /// </summary>
        Task<BitmapImage> LoadAsync(string path);

        /// <summary>
        /// Renders the background + overlay and writes two PNGs:
        ///   • primaryPath: composite of background+overlay
        ///   • overlayPath (optional): overlay alone
        /// Returns the actual paths written.
        /// </summary>
        Task<(string primaryPath, string? overlayPath)> SaveAsync(
            FrameworkElement overlay,
            BitmapImage background,
            string primaryPath,
            string? overlayPath = null);
    }
}