using System;
using System.Collections.Generic;
using System.IO;
using ln.http.exceptions;

namespace ln.build
{
    public static class PathHelper
    {

        public static IEnumerable<string> ResolvePattern(string pattern) => ResolvePattern(pattern, Environment.CurrentDirectory);
        public static IEnumerable<string> ResolvePattern(string pattern, string start)
        {
            string[] patternTokens = pattern.Split('/', StringSplitOptions.RemoveEmptyEntries);
            List<string> matches = new List<string>();
            collect(patternTokens, 0, start, matches);
            return matches;
        }

        static void collect(string[] tokens,int depth,string currentPath, List<string> matches)
        {
            if (depth < tokens.Length-1)
            {
                foreach (string dirname in Directory.GetDirectories(currentPath, tokens[depth]))
                {
                    collect(tokens, depth + 1, dirname, matches);
                }
            } else if (depth == (tokens.Length - 1))
            {
                foreach (string filename in Directory.GetFiles(currentPath, tokens[depth]))
                {
                    matches.Add(filename);
                }
            } else
                throw new Exception("serious bug");
        }



    }
}