bfr/BFR/Operations/Number.cs

using System;
using System.Linq;
using System.Xml.Serialization;
using System.Collections.Generic;

using Avalonia;

using BFR.Helpers;
using BFR.DataModels;

namespace BFR.Operations
{
    public class Number : Operation
    {
        public override string Name => nameof(Number);
        public override string Description => "Numbers all file names according to how they are sorted.";

        public static readonly AvaloniaProperty<NumberMode> ModeProperty = 
            AvaloniaProperty.Register<MainWindow, NumberMode>(nameof(Mode), NumberMode.Prepend);
        public NumberMode Mode { get => GetValue(ModeProperty); set => SetValue(ModeProperty, value); }

        [XmlIgnore]
        public NumberOperationMode[] Modes => NumberOperationMode.Modes;

        public int InsertPosition { get; set; } = 0;
        public int Increment { get; set; } = 1;
        public int StartIndex { get; set; } = 1;
        public int Padding { get; set; } = 0;
        public bool AutoPadding { get; set; } = false;
        public bool FullName { get; set; } = false;
        public bool UseRegex { get; set; } = false;
        public string Pattern { get; set; } = "";

        protected override void ApplyToInternal(IList<FileModel> files)
        {
            var index = StartIndex;
            var padding = AutoPadding
                ? (StartIndex + Increment * (files.Count - 1)).ToString().Length
                : Padding;

            // Fail conditions: Out of bounds insert
            var shortestLength = files.Min(x => FullName ? x.FullName.Length : x.Name.Length);
            if (Mode == NumberMode.Insert && InsertPosition > shortestLength) throw new OperationException($"First N can't be greater than the shortest file name length ({shortestLength}).");

            // Regex Failure
            if (Mode == NumberMode.Replace && UseRegex)
                try { "".Replace(Pattern, "", true, false); }
                catch (Exception) { throw new OperationException("Invalid Regex Pattern."); }

            // Apply operation
            foreach (var file in files)
            {
                var newName = FullName ? file.FullName : file.Name;
                var text = PadInteger(index, padding);

                newName = Mode switch
                {
                    NumberMode.Prepend => $"{text}{newName}",
                    NumberMode.Append => $"{newName}{text}",
                    NumberMode.Insert => newName.Insert(InsertPosition, text),
                    NumberMode.Replace => newName.Replace(Pattern, text, UseRegex, false),
                    _ => newName
                };

                if (FullName) file.FullName = newName;
                else file.Name = newName;

                index += Increment;
            }
        }

        private static string PadInteger(int value, int padding)
        {
            var valueString = value.ToString();
            while (valueString.Length < padding)
                valueString = $"0{valueString}";

            return valueString;
        }
    }
}