ClubPenguinClient/MareSynchronos/Utils/FileReplacementComparer.cs

using MareSynchronos.Models;

namespace MareSynchronos.Utils;

public class FileReplacementComparer : IEqualityComparer<FileReplacement>
{
    public static FileReplacementComparer Instance => _instance;
    private static FileReplacementComparer _instance = new();
    private FileReplacementComparer() { }
    public bool Equals(FileReplacement? x, FileReplacement? y)
    {
        if (x == null || y == null) return false;
        return x.ResolvedPath.Equals(y.ResolvedPath) && CompareLists(x.GamePaths, y.GamePaths);
    }

    public int GetHashCode(FileReplacement obj)
    {
        return HashCode.Combine(obj.ResolvedPath.GetHashCode(StringComparison.OrdinalIgnoreCase), GetOrderIndependentHashCode(obj.GamePaths));
    }

    private static int GetOrderIndependentHashCode<T>(IEnumerable<T> source)
    {
        int hash = 0;
        foreach (T element in source)
        {
            hash = unchecked(hash +
                EqualityComparer<T>.Default.GetHashCode(element));
        }
        return hash;
    }

    private bool CompareLists(List<string> list1, List<string> list2)
    {
        if (list1.Count != list2.Count)
            return false;

        for (int i = 0; i < list1.Count; i++)
        {
            if (!string.Equals(list1[i], list2[i], StringComparison.OrdinalIgnoreCase))
                return false;
        }

        return true;
    }
}