MeWeb/src/MeWeb.Core/Knowledge/Providers.cs

using System.Text.Json;
using System.Text.Json.Serialization;

namespace MeWeb.Core.Knowledge;

public class ProviderFact
{
  public string Value { get; set; }
  public decimal? Price { get; set; }
  public string Currency { get; set; }
  public string Basis { get; set; }
  public string Source { get; set; }
  public string Date { get; set; }
}

public class ProviderProfile
{
  public string Name { get; set; }
  public string Country { get; set; }
  public List<uint> Asns { get; set; } = [];
  public string Sheet { get; set; }
  public ProviderFact Ipv4 { get; set; }
  public ProviderFact PublicAddress { get; set; }
  public ProviderFact Ipv6 { get; set; }
  public ProviderFact Port25 { get; set; }
}

[JsonSourceGenerationOptions(JsonSerializerDefaults.Web)]
[JsonSerializable(typeof(ProviderProfile))]
public partial class KnowledgeJsonContext : JsonSerializerContext
{
}

public sealed class KnowledgeBase
{
  readonly Lazy<AsnTable> asn = new(LoadAsn);
  readonly Lazy<List<ProviderProfile>> providers = new(LoadProviders);

  public bool HasAsnTable => typeof(KnowledgeBase).Assembly.GetManifestResourceInfo("ip2asn.bin") is not null;

  public AsnTable Asn => asn.Value;

  public IReadOnlyList<ProviderProfile> Providers => providers.Value;

  public ProviderProfile ProviderFor(uint number) => number == 0 ? null : Providers.FirstOrDefault(p => p.Asns.Contains(number));

  static AsnTable LoadAsn()
  {
    using var stream = typeof(KnowledgeBase).Assembly.GetManifestResourceStream("ip2asn.bin");
    return stream is null ? null : AsnTable.Read(stream);
  }

  static List<ProviderProfile> LoadProviders()
  {
    var assembly = typeof(KnowledgeBase).Assembly;
    var list = new List<ProviderProfile>();
    foreach (var name in assembly.GetManifestResourceNames().Where(n => n.StartsWith("isp.", StringComparison.Ordinal)).Order(StringComparer.Ordinal))
    {
      using var stream = assembly.GetManifestResourceStream(name);
      var profile = JsonSerializer.Deserialize(stream, KnowledgeJsonContext.Default.ProviderProfile);
      if (profile is not null) list.Add(profile);
    }
    return list;
  }
}