using System.Reflection;

namespace SushiBarContracts.DI;

public static partial class ServiceProviderLoader
{
    public static IImplementationExtension? GetImplementationExtensions()
    {
        IImplementationExtension? source = null;
        var files =
            Directory.GetFiles(TryGetImplementationExtensionsFolder(), "*.dll",
                SearchOption.AllDirectories);
        foreach (var file in files.Distinct())
        {
            var asm = Assembly.LoadFrom(file);
            foreach (var t in asm.GetExportedTypes())
            {
                if (!t.IsClass || !typeof(IImplementationExtension).IsAssignableFrom(t)) continue;
                if (source == null)
                {
                    source = (IImplementationExtension)Activator.CreateInstance(t)!;
                }
                else
                {
                    var newSource = (IImplementationExtension)Activator.CreateInstance(t)!;
                    if (newSource.Priority > source.Priority)
                    {
                        source = newSource;
                    }
                }
            }
        }
        return source;
    }
    private static string TryGetImplementationExtensionsFolder()
    {
        var directory = new
            DirectoryInfo(Directory.GetCurrentDirectory());
        while (directory != null && directory
                   .GetDirectories("ImplementationExtensions", SearchOption.AllDirectories)
                   .All(x => x.Name != "ImplementationExtensions"))
        {
            directory = directory.Parent;
        }
        return $"{directory?.FullName}\\ImplementationExtensions";
    }
}