ThemeIcon.cs

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

namespace ReplaceIcon
{
    public class ThemeIcon
    {
        public string SizePattern { get; private set; }

        public List<IconSize> Sizes { get; private set; }

        public string this[string size]
        {
            get
            {
                if (Sizes.All(s => s.Size != size))
                    throw new Exception("Unsupported size");

                return string.Format(SizePattern, size);
            }
        }

        public string this[IconSize size]
        {
            get
            {
                if (!Sizes.Contains(size))
                    throw new Exception("Unsupported size");

                return string.Format(SizePattern, size.Size);
            }
        }

        public ThemeIcon(string path)
        {
            Sizes = GetSizes(path);
            SizePattern = GetSizePattern(path);
        }

        private string GetSizePattern(string path)
        {
            var parts = path.Split('/');

            if (Sizes.Any(s => s.Size == parts[parts.Length - 2]))
            {
                parts[parts.Length - 2] = "{0}"; //     .../CaledoniaTheme/apps/{0}/firefox.png
            }
            else if (Sizes.Any(s => s.Size == parts[parts.Length - 3]))
            {
                parts[parts.Length - 3] = "{0}"; //     .../CaledoniaTheme/{0}/apps/firefox.png
            }

            string pattern = string.Join("/", parts);

            return pattern;
        }

        private List<IconSize> GetSizes(string path)
        {
            var types = new [] { new Regex("[1-9]+[0-9]+"), new Regex("[1-9]+[0-9]+x[1-9]+[0-9]+") }; // ex.:    64    64x64

            var parts = path.Split('/');

            if (types[0].IsMatch(parts[parts.Length - 2]) || types[0].IsMatch(parts[parts.Length - 3]))
                return new List<IconSize>()
                {
                    new IconSize("16", "16x16"),
                    new IconSize("22", "22x22"),
                    new IconSize("24", "24x24"),
                    new IconSize("32", "32x32"),
                    new IconSize("64", "64x64"),
                    new IconSize("128", "128x128"),
                    new IconSize("256", "256x256"),
                    new IconSize("512", "512x512"),
                    new IconSize("scalable")
                };

            if (types[1].IsMatch(parts[parts.Length - 2]) || types[1].IsMatch(parts[parts.Length - 3]))
                return new List<IconSize>()
                {
                    new IconSize("16x16", "16"),
                    new IconSize("22x22", "22"),
                    new IconSize("24x24", "24"),
                    new IconSize("32x32", "32"),
                    new IconSize("64x64", "64"),
                    new IconSize("128x128", "128"),
                    new IconSize("256x256", "256"),
                    new IconSize("512x512", "512"),
                    new IconSize("scalable")
                };

            throw new Exception("Unknown size type");
        }
    }
}