using System;

using System.Collections.Generic;

using System.Security.Claims;

using System.Linq;

public class Program

{

    public static void Main()

    {

        // Convert the snowflake value to a list of permissions

        long snowflake = 10;

​

        Console.WriteLine( "What are the permissions if snowflake is {0}:", snowflake);

        IList<string> permissions = CustomClaimsPermissions.PermissionConverter.ConvertFromLong(snowflake, CustomClaimsPermissions.GetDefaultPermissions());

        foreach (var p in permissions){

            Console.WriteLine(p);   

        }

​

        var permissionsToSnowFlake = new List<string>()

            {

                CustomClaimsPermissions.SystemDisplayGroups,

                CustomClaimsPermissions.SystemUnits,

            };

​

        // Convert a list of permissions to snowflake

        Console.WriteLine( "Convert permissions to snowflake: {0}", CustomClaimsPermissions.PermissionConverter.ConvertToLong(permissionsToSnowFlake, CustomClaimsPermissions.GetDefaultPermissions()));

​

        // Check the corresponding bit in the snowflake value to see if the permission is set

        var permissionNames = CustomClaimsPermissions.GetDefaultPermissions();

        var checkPermission = CustomClaimsPermissions.SystemAssets;

        Console.WriteLine("If a user has a snowflake {0}, check if he has permissions to {1}", snowflake, checkPermission);

        int permissionBit = Array.IndexOf(permissionNames.ToArray(), checkPermission);

        var hasClaim = (snowflake & (1 << permissionBit)) != 0;

        Console.WriteLine("Has {0}:{1}", checkPermission, hasClaim);

​

        // Add new permission

        // Convert the snowflake value to a list of permissions

        IList<string> currentPermissions = CustomClaimsPermissions.PermissionConverter.ConvertFromLong(snowflake, CustomClaimsPermissions.GetDefaultPermissions());

​

        var newPermission = CustomClaimsPermissions.SystemAssets;

        // Add the new permission to the list of permissions

        currentPermissions.Add(newPermission);

​

        // Convert the updated list of permissions back to a snowflake value

        long updatedSnowflake = CustomClaimsPermissions.PermissionConverter.ConvertToLong(currentPermissions, CustomClaimsPermissions.GetDefaultPermissions());

​

        Console.WriteLine("New snowflake: {0}", updatedSnowflake);

​

        // Check the corresponding bit in the snowflake value to see if the permission is set

        Console.WriteLine("If a user has a snowflake {0}, check if he has permissions to {1}", updatedSnowflake, checkPermission);

        permissionBit = Array.IndexOf(permissionNames.ToArray(), checkPermission);

        hasClaim = (updatedSnowflake & (1 << permissionBit)) != 0;

        Console.WriteLine("Has {0}:{1}", checkPermission, hasClaim);

​

    }

    public static class CustomClaimsPermissions

    {

        public const string SystemAssets = "System: Assets";

        public const string SystemDisplayGroups = "System: Display Groups";

        public const string SystemMap = "System: Map";

        public const string SystemUnits = "System: Units";

        public const string SystemUsers = "System: Users";

        public const string SystemCustomers = "System: Customers";

​

        public static IList<string> GetDefaultPermissions()

        {

            return new List<string>()

            {

                SystemAssets,

                SystemDisplayGroups,

                SystemMap,

                SystemUnits,

                SystemUsers,

                SystemCustomers,

            };

        }

​

        public static class PermissionConverter

        {

            public static long ConvertToLong(IList<string> permissions, IList<string> permissionNames)

            {

                long result = 0;

​

                for (int i = 0; i < permissionNames.Count; i++)

                {

                    if (permissions.Contains(permissionNames[i]))

                    {

                        result += (long) Math.Pow(2, i);

                    }

                }

​

                return result;

            }

​

            public static IList<string> ConvertFromLong(long value, IList<string> permissionNames)

            {

                List<string> permissions = new List<string>();

​

                for (int i = 0; i < permissionNames.Count; i++)

                {

                    if ((value & (1L << i)) != 0)

                    {

                        permissions.Add(permissionNames[i]);

                    }

                }

​

                return permissions;

            }

            public static bool HasPermission(ClaimsPrincipal user, string permission)

            {

                IList<string> permissionNames = GetDefaultPermissions();

                // Get the snowflake claim from the user's claims

                Claim snowflakeClaim = user.Claims.FirstOrDefault(c => c.Type == "snowflake");

                if (snowflakeClaim == null)

                {

                    return false;

                }

​

                // Parse the snowflake value from the claim

                long snowflake;

                if (!long.TryParse(snowflakeClaim.Value, out snowflake))

                {

                    return false;

                }

​

                // Check the corresponding bit in the snowflake value to see if the permission is set

                int permissionBit = Array.IndexOf(permissionNames.ToArray(), permission);

                return (snowflake & (1 << permissionBit)) != 0;

            }

            public static void UpdateUserPermissions(ClaimsPrincipal user, string newPermission)

            {

                // Get the snowflake claim from the user's claims

                Claim snowflakeClaim = user.Claims.FirstOrDefault(c => c.Type == "snowflake");

                if (snowflakeClaim == null)

                {

                    // The user doesn't have a snowflake claim, so we can't update their permissions

                    return;

                }

​

                // Parse the snowflake value from the claim

                long snowflake;

                if (!long.TryParse(snowflakeClaim.Value, out snowflake))

                {

                    // The snowflake value is invalid, so we can't update the user's permissions

                    return;

                }

​

                // Convert the snowflake value to a list of permissions

                IList<string> permissions = ConvertFromLong(snowflake, GetDefaultPermissions());

​

                // Add the new permission to the list of permissions

                permissions.Add(newPermission);

​

                // Convert the updated list of permissions back to a snowflake value

                long updatedSnowflake = ConvertToLong(permissions, GetDefaultPermissions());

​

                // Update the snowflake claim with the new snowflake value

                user.Identities.First().AddClaim(new Claim("snowflake", updatedSnowflake.ToString()));

            }

        }

    }

}