using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using PInvoke;

namespace AssetBrowser
{
    class BasicFileEnumerator : FileEnumerator
    {
        public IEnumerable<string> GetAllFiles(string _folder)
        {
            if (String.IsNullOrEmpty(_folder))
                yield break;

            if (!Directory.Exists(_folder))
                yield break;

            foreach (string file in EnumerateDir(_folder))
            {
                yield return file;
            }
        }

        private IEnumerable<string> EnumerateDir(string _folder)
        {
            Win32Api.WIN32_FIND_DATA findData;
            string searchString = Path.Combine(_folder, "*");
            IntPtr hFind = Win32Api.FindFirstFile(searchString, out findData);
            if (hFind.ToInt32() != Win32Api.INVALID_HANDLE_VALUE)
            {
                do
                {
                    if ((findData.dwFileAttributes & Win32Api.FILE_ATTRIBUTE_DIRECTORY) != 0)
                    {
                        if (findData.cFileName != "." && findData.cFileName != "..")
                        {
                            foreach (string filename in EnumerateDir(Path.Combine(_folder, findData.cFileName)))
                                yield return filename;
                        }
                    }
                    else
                    {
                        yield return findData.cFileName;
                    }
                } while (Win32Api.FindNextFile(hFind, out findData));
                Win32Api.FindClose(hFind);
            }
        }
    }
}