Scratch of the Document Import I'm working on.

Document Import Design

using System;
using System.IO;
using System.Text.RegularExpressions;

namespace DocImportStrategies
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
        }
    }

    // As-is, for now...
    interface IDocImporter 
    {
        protected IImportStrategy<T> Import<T>();
        
        /*The following are default Import strategies that go in the abstract base class*/
        
        // FileInfo GetFiles(params string[] delimiters);
        // FileInfo GetFiles(Regex pattern);
    }

    abstract class DocImporter
    {
        public DocImporter(IImportStrategy<object> strategy)
        {
            
        }
        protected abstract bool Import<T>();
    }
    
    class GovInsImporter : DocImporter
    {
        // Implements the running of import steps for this importer
        void Feature1()
        {
        }

        void Feature2()
        {
        }

        public GovInsImporter(IImportStrategy<object> strategy) : base(strategy)
        {
        }

        protected override bool Import<T>() => throw new NotImplementedException();
    }


    interface IImportStrategy<out TDocType>
    {
        IImportStrategy<TDocType> Step1();
        IImportStrategy<TDocType> Step2();
        TDocType Finish(); //Final step of import
    }

    // Employ the extract() extension method on DocumentParts
    abstract class ImportDoc
    {
        // Accessed by the Importer's strategy
        public Regex Pattern { get; }
        ImportDoc(string pattern){}
        
        // Actual data:
        protected FileInfo Document { get;}
        FileNameParts Parts { get; }
    }

    // The delimited pieces of a file's name
    class FileNameParts
    {
        public string LoanNumber { get; }
        public string SpecificType1 { get; }
        public string SpecificType2 { get; }
        public string MersMinNumber { get; }
        public string Time { get; }
        // etc.
    }
    
    public partial interface ISpecification<in TSubject>
    {
        bool IsSatisfiedBy(TSubject candidate);
    }

    interface ImportableDoc
    {
        // Detect a file name match
         Regex pattern { get; }
         // Updates the pattern with delimiters
         ImportableDoc Delimit(string[] delimiters);
    }

    class HVAADoc : ImportableDoc
    {
        public Regex pattern { get; }
        public ImportableDoc Delimit(string[] delimiters) => throw new NotImplementedException();
    }

    class NotesDoc : ImportableDoc
    {
        public Regex pattern { get; }
        public ImportableDoc Delimit(string[] delimiters) => throw new NotImplementedException();
    }
}