using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Test_ChangeOrder
{
    internal class RenameFiles
    {
        public List<string> Rename(List<string> files)
        {
            //Dateien nach dem verschieben umbenennen, damit die Nummer im Dateinamen mitder Reihung übereinstimmt
            int number = 0;
            string fileName = "";
            //string tempFileName = "";
            string file = "";
            string path = "";

            System.IO.File.Move(files[files.Count - 1], Path.GetDirectoryName(files[files.Count - 1]) + "\\" + Path.GetFileNameWithoutExtension(files[files.Count - 1]) + "_" + Path.GetExtension(files[files.Count - 1]));

            for (int i = 0; i < files.Count; i++)
            {
                file = Path.GetFileName(files[i]);
                path = Path.GetDirectoryName(files[i]);

                number = Convert.ToInt32(file.Remove(file.IndexOf(" ")));
                fileName = file.Remove(0, file.IndexOf(" "));

                if (number != i + 1)
                {
                    //Umbenennen
                    if (i + 1 < 10)
                    {
                        fileName = path + "\\0" + (i + 1).ToString() + fileName;
                    }
                    else
                    {
                        fileName = path + "\\" + (i + 1).ToString() + fileName;
                    }

                    try
                    {
                        if (i == files.Count - 1)
                        {
                            System.IO.File.Move(Path.GetDirectoryName(files[i]) + "\\" + Path.GetFileNameWithoutExtension(files[i]) + "_" + Path.GetExtension(files[i]), fileName); //Wenn der letzte Eintrag
                        }
                        else
                        {
                            System.IO.File.Move(files[i], fileName); //Alle, ausser dem letzten Eintrag
                        }
                    }
                    catch (Exception)
                    {
                        MessageBox.Show("Datei konnte nicht umbenannt werden.", "Fehler", MessageBoxButtons.OK);
                    } 

                    files[i] = fileName;
                }
            }

            for (int j = 0; j < files.Count - 1; j++)
            {
                if (Path.GetFileNameWithoutExtension(files[j]).EndsWith("_"))
                {
                    files[j] = Path.GetDirectoryName(files[j]) + "\\" + Path.GetFileNameWithoutExtension(files[j]).Remove(Path.GetFileNameWithoutExtension(files[j]).Length - 1) + Path.GetExtension(files[j]);
                }
            }

            return files;
        }
    }
}