mcdiscordbot/MinecraftDiscordBot/Models/Md5Hash.cs

using Newtonsoft.Json;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;

namespace MinecraftDiscordBot.Models;

[JsonConverter(typeof(Md5JsonConverter))]
[DebuggerDisplay($"{{{nameof(ToString)}(),nq}}")]
public class Md5Hash : IEquatable<Md5Hash?> {
    private readonly byte[] _hash;
    public Md5Hash(string hash) : this(Convert.FromHexString(hash)) { }
    public Md5Hash(byte[] hash) {
        if (hash is not { Length: 16 }) throw new ArgumentException("Invalid digest size!", nameof(hash));
        _hash = hash;
    }
    public override bool Equals(object? obj) => Equals(obj as Md5Hash);
    public bool Equals(Md5Hash? other) => other != null && _hash.SequenceEqual(other._hash);
    public override int GetHashCode() {
        var hashCode = new HashCode();
        hashCode.AddBytes(_hash);
        return hashCode.ToHashCode();
    }
    public override string ToString() => Convert.ToHexString(_hash).ToLower();

    public class Md5JsonConverter : JsonConverter<Md5Hash> {
        public override Md5Hash? ReadJson(JsonReader reader, Type objectType, Md5Hash? existingValue, bool hasExistingValue, JsonSerializer serializer)
            => reader.Value is string { Length: 32 } value
                ? new(value)
                : throw new JsonException($"Could not parse MD5 hash with token '{reader.Value}'");
        public override void WriteJson(JsonWriter writer, Md5Hash? value, JsonSerializer serializer) {
            if (value is null) writer.WriteNull();
            else writer.WriteValue(value.ToString());
        }
    }

    public static bool TryParse(string itemid, [NotNullWhen(true)] out Md5Hash? fingerprint) {
        try {
            fingerprint = new Md5Hash(itemid);
            return true;
        } catch (Exception) {
            fingerprint = null;
            return false;
        }
    }
}