using System;
using System.ComponentModel;
using System.IO;
using System.Runtime.InteropServices;

namespace QVCopier.Utility.FindFile
{
    internal static class FindFileApi
    {
        [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        private static extern IntPtr FindFirstFileEx(
            string lpFileName,
            FINDEX_INFO_LEVELS fInfoLevelId,
            out WIN32_FIND_DATA lpFindFileData,
            FINDEX_SEARCH_OPS fSearchOp,
            IntPtr lpSearchFilter,
            int dwAdditionalFlags);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        private static extern bool FindNextFile(IntPtr hFindFile, out WIN32_FIND_DATA lpFindFileData);

        [DllImport("kernel32.dll")]
        private static extern bool FindClose(IntPtr hFindFile);

        // dwAdditionalFlags:
        private const int FIND_FIRST_EX_CASE_SENSITIVE = 1;

        private const int FIND_FIRST_EX_LARGE_FETCH = 2;

        public static void Find(string fileNameOrPath)
        {
            FINDEX_INFO_LEVELS findInfoLevel = FINDEX_INFO_LEVELS.FindExInfoStandard;
            int additionalFlags = 0;
            if (Environment.OSVersion.Version.Major >= 6)
            {
                findInfoLevel = FINDEX_INFO_LEVELS.FindExInfoBasic;
                additionalFlags = FIND_FIRST_EX_LARGE_FETCH;
            }

            var hFile = FindFirstFileEx(
                fileNameOrPath,
                findInfoLevel,
                out var findData,
                FINDEX_SEARCH_OPS.FindExSearchNameMatch,
                IntPtr.Zero,
                additionalFlags);

            int error = Marshal.GetLastWin32Error();

            if (error == 2)
            {
                hFile = FindFirstFileEx(
                    Path.Combine(fileNameOrPath, "*.*"),
                    findInfoLevel,
                    out findData,
                    FINDEX_SEARCH_OPS.FindExSearchNameMatch,
                    IntPtr.Zero,
                    additionalFlags);
            }

            if (hFile.ToInt32() != -1)
            {
                do
                {
                    if ((findData.dwFileAttributes & FileAttributes.Directory) != FileAttributes.Directory)
                    {
                        Console.WriteLine("File {0}", findData.cFileName);
                    }
                    else
                    {
                        Console.WriteLine("Dir {0}", findData.cFileName);
                    }
                }
                while (FindNextFile(hFile, out findData));

                FindClose(hFile);
            }
            else
            {
                var ex = new Win32Exception();
            }
        }
    }
}