TwoFactorExtension.cs

// This file is part of the DisCatSharp project.
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// Copyright (c) 2021-2023 AITSYS
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using System;
using System.Collections.Generic;
using System.Reflection;

using DatabaseWrapper.Core;
using DatabaseWrapper.Sqlite;

using ExpressionTree;

using TwoFactorAuthNet;

namespace DisCatSharp.Extensions.TwoFactorCommands;

/// <summary>
///     Represents a <see cref="TwoFactorExtension" />.
/// </summary>
public sealed class TwoFactorExtension : BaseExtension
{
	/// <summary>
	///     Gets the secret field name.
	/// </summary>
	private readonly string _secretField = "secret";

	/// <summary>
	///     Gets the table name.
	/// </summary>
	private readonly string _tableName = "twofactor_mapper";

	/// <summary>
	///     Gets the user field name.
	/// </summary>
	private readonly string _userField = "user";

	/// <summary>
	///     Initializes a new instance of the <see cref="TwoFactorExtension" /> class.
	/// </summary>
	/// <param name="configuration">The config.</param>
	internal TwoFactorExtension(TwoFactorConfiguration? configuration = null)
	{
		configuration ??= new();
		this.Configuration = configuration;
		this.TwoFactorClient = new(configuration.Issuer, configuration.Digits, configuration.Period, configuration.Algorithm);

		this.DatabaseClient = new(this.Configuration.DatabasePath);
		if (this.DatabaseClient.TableExists(this._tableName))
			return;

		var columns = new List<Column>
		{
			new(this._userField, true, DataTypeEnum.Varchar, 128, null, false),
			new(this._secretField, false, DataTypeEnum.Varchar, 512, null, false)
		};
		this.DatabaseClient.CreateTable(this._tableName, columns);
	}

	/// <summary>
	///     Gets the two factor configuration.
	/// </summary>
	internal TwoFactorConfiguration Configuration { get; }

	/// <summary>
	///     Gets the database client.
	/// </summary>
	internal DatabaseClient DatabaseClient { get; }

	/// <summary>
	///     Gets the tfa client.
	/// </summary>
	internal TwoFactorAuth TwoFactorClient { get; }

	/// <summary>
	///     Gets the service provider this TwoFactor module was configured with.
	/// </summary>
	public IServiceProvider Services
		=> this.Configuration.ServiceProvider;

	/// <summary>
	///     DO NOT USE THIS MANUALLY.
	/// </summary>
	/// <param name="client">DO NOT USE THIS MANUALLY.</param>
	/// <exception cref="InvalidOperationException" />
	protected internal override void Setup(DiscordClient client)
	{
		if (this.Client != null)
			throw new InvalidOperationException("What did I tell you?");

		this.Client = client;

		var a = typeof(TwoFactorExtension).GetTypeInfo().Assembly;

		var iv = a.GetCustomAttribute<AssemblyInformationalVersionAttribute>();
		if (iv != null)
			this.VersionString = iv.InformationalVersion;
		else
		{
			var v = a.GetName().Version;
			var vs = v!.ToString(3);

			if (v.Revision > 0)
				this.VersionString = $"{vs}, CI build {v.Revision}";
		}

		this.HasVersionCheckSupport = true;

		this.RepositoryOwner = "Aiko-IT-Systems";

		this.Repository = "DisCatSharp.Extensions";

		this.PackageId = "DisCatSharp.Extensions.OAuth2Web";
	}

	/// <summary>
	///     Checks whether the database has info about the given user id.
	/// </summary>
	/// <param name="user">The user id to check.</param>
	/// <returns></returns>
	private bool HasData(ulong user)
		=> this.DatabaseClient.Exists(this._tableName, new(this._userField, OperatorEnum.Equals, user.ToString()));

	/// <summary>
	///     Gets the secret for the given user id from the database.
	/// </summary>
	/// <param name="user">The user id to get data for.</param>
	private string GetSecretFor(ulong user)
		=> this.DatabaseClient.Select(this._tableName, null, 1, null, new(this._userField, OperatorEnum.Equals, user.ToString())).Rows[0].ItemArray[1]!.ToString()!;

	/// <summary>
	///     Adds a secret for the given user id to the database.
	/// </summary>
	/// <param name="user">The user id to add data for.</param>
	/// <param name="secret">The secret to add.</param>
	private void AddSecretFor(ulong user, string secret)
	{
		Dictionary<string, object> data = new()
		{
			{ this._userField, user.ToString() },
			{ this._secretField, secret }
		};
		this.DatabaseClient.Insert(this._tableName, data);
	}

	/// <summary>
	///     Removes a secret for the given user id in the database.
	/// </summary>
	/// <param name="user">The user id to remove data for.</param>
	private void RemoveSecret(ulong user)
		=> this.DatabaseClient.Delete(this._tableName, new(this._userField, OperatorEnum.Equals, user.ToString()));

	/// <summary>
	///     Checks whether the two factor auth code is valid for given user id.
	/// </summary>
	/// <param name="user">The user id entering the code.</param>
	/// <param name="code">The code to check.</param>
	/// <returns>Whether the code is valid.</returns>
	public bool IsValidCode(ulong user, string code)
		=> this.HasData(user) && this.TwoFactorClient.VerifyCode(this.GetSecretFor(user), code);

	/// <summary>
	///     Checks whether given user id is enrolled in two factor auth.
	/// </summary>
	/// <param name="user">User id to check for enrollment.</param>
	/// <returns>Whether the user is enrolled.</returns>
	public bool IsEnrolled(ulong user)
		=> this.HasData(user);

	/// <summary>
	///     Enrolls given user id with two factor auth.
	/// </summary>
	/// <param name="user">User id to enroll.</param>
	/// <param name="secret">Secret to use.</param>
	public void EnrollUser(ulong user, string secret)
		=> this.AddSecretFor(user, secret);

	/// <summary>
	///     Unenrolls given user id from two factor auth.
	/// </summary>
	/// <param name="user">User id to unenroll.</param>
	public void DisenrollUser(ulong user)
		=> this.RemoveSecret(user);
}