Rename from explorer Code

// Copyright 2013-2023 Eric Raijmakers.
//
// This file is part of "Rename from explorer".
//
// Vidiot is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Vidiot is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Vidiot. If not, see <http://www.gnu.org/licenses/>.

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

namespace Renamer
{
    public class Preset
    {
        public string Name { get; set; }
        public List<Row> Rows { get; set; } = new List<Row>();

        public List<string> Rename(Input input)
        {
            input.Time = DateTime.Now;
            input.NewFiles = input.Files.Select(f => f).ToList();
            Rows.ForEach(r => r.Apply(input));

            // Ensure that no name clashes will occur
            List<string> renamedFiles = input.NewFiles;
            for (int i = 0; i < renamedFiles.Count; ++i)
            {

                Func<string, int, string> AppendSuffix = (name, n) =>
                {
                    return 
                        Path.Combine(
                            Path.GetDirectoryName(name), 
                            Path.GetFileNameWithoutExtension(name) + " (" + n.ToString() + ")" + Path.GetExtension(name));
                };

                Func<int, bool> IsChanged = (n) => ! input.Files[n].Equals(input.NewFiles[n]);

                string oldName = input.Files[i];
                string newName = renamedFiles[i];
                if (IsChanged(i))
                {
                    // Only update file names (with suffixes) if the file was actually going to be renamed.
                    if ((File.Exists(newName) && oldName.ToLower() != newName.ToLower()) || // File with the new name already exists and is not the renamed file
                        (input.NewFiles.Where(x => x.Equals(newName)).Count() > 1)) // Multiple renamed files will end up with the same name
                    {
                        string newNameWithSuffix = newName;
                        int suffix = 1;
                        for (int j = 0; j < renamedFiles.Count; ++j)
                        {
                            if (IsChanged(j) && 
                                renamedFiles[j] == newName)
                            {
                                renamedFiles[j] = AppendSuffix(newName, suffix);
                                ++suffix;
                            }
                        }
                        i = 0; // Check from beginning again to ensure that the suffixes themselves cause no additional clashes
                    }
                }
            }

            return renamedFiles;
        }
    }
}