using System.Reflection;

namespace SushiBarContracts.DI;

public static partial class ServiceProviderLoader
{
    public static List<IImplementationExtension?> GetImplementationExtensions()
    {
        Type[] types =
        {
            typeof(ILogicImplementationExtension),
            typeof(IImplementationExtension)
        };
        var trueTypes = types.Select(x => (IImplementationExtension?)null).ToList();
        var files = Directory.GetFiles(TryGetImplementationExtensionsFolder(), "*.dll", SearchOption.AllDirectories);
        foreach (var file in files.Distinct())
        {
            Assembly asm = Assembly.LoadFrom(file);
            foreach (var t in asm.GetExportedTypes())
            {
                for (var i = 0; i < types.Length; i++)
                {
                    if (t.IsClass && types[i].IsAssignableFrom(t))
                    {
                        if (trueTypes[i] == null)
                        {
                            trueTypes[i] = (IImplementationExtension)Activator.CreateInstance(t)!;
                        }
                        else
                        {
                            var newSource = (IImplementationExtension)Activator.CreateInstance(t)!;
                            if (newSource.Priority > trueTypes[i].Priority)
                            {
                                trueTypes[i] = newSource;
                            }
                        }
                    }
                }
            }
        }
        return trueTypes;
    }
    
    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";
    }
}