// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Globalization;

namespace System
{
    internal static partial class LocalAppContextSwitches
    {
        internal const int DefaultMaxRecursionDepth = 64;
        internal const string DangerousMaxRecursionDepthAppContextSwitch = "System.Security.Cryptography.Xml.DangerousMaxRecursionDepth";
        internal const string AllowDangerousEncryptedXmlTransformsAppContextSwitch = "System.Security.Cryptography.Xml.AllowDangerousEncryptedXmlTransforms";

        // 0 disables the limit for compatibility. Negative values fall back to the default.
        internal static int DangerousMaxRecursionDepth { get; } =
            GetInt32Config(DangerousMaxRecursionDepthAppContextSwitch, DefaultMaxRecursionDepth, allowNegative: false);

        internal static bool AllowDangerousEncryptedXmlTransforms { get; } =
            GetBooleanConfig(AllowDangerousEncryptedXmlTransformsAppContextSwitch, defaultValue: false);

        internal static int MaxReferencesPerSignedInfo { get; } =
            GetInt32Config("System.Security.Cryptography.MaxReferencesPerSignedInfo", defaultValue: 100);

        private static int GetInt32Config(string appContextName, int defaultValue, bool allowNegative = true)
        {
            object? data = AppContext.GetData(appContextName);

            if (data is null)
            {
                return defaultValue;
            }

            int value;

            try
            {
                value = Convert.ToInt32(data, CultureInfo.InvariantCulture);
            }
            catch
            {
                return defaultValue;
            }

            return (allowNegative || value >= 0) ? value : defaultValue;
        }

        private static bool GetBooleanConfig(string appContextName, bool defaultValue)
        {
            if (AppContext.TryGetSwitch(appContextName, out bool isEnabled))
            {
                return isEnabled;
            }

            return defaultValue;
        }
    }
}