Biskilog_Cloud_Manager/Cloud_Manager/Models/ServiceRepo/TokenService.cs

using Cloud_Manager.Models.ClientContractModels;
using Cloud_Manager.Models.Enums;
using Cloud_Manager.Models.Interfaces;
using Microsoft.EntityFrameworkCore.Metadata.Internal;
using Microsoft.Extensions.Configuration;
using Microsoft.IdentityModel.Tokens;
using System;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;

namespace Cloud_Manager.Models.ServiceRepo
{
    public class TokenService : IKeyService
    {
        private IConfiguration m_configuration { get; }
        private readonly Random m_random;
        private BiskilogContext m_context;
        public TokenService(IConfiguration a_configuration, BiskilogContext a_context)
        {
            m_configuration = a_configuration;
            m_context = a_context;
            m_random = new Random();
        }

        public AuthEnums ValidateKey(string a_Key)
        {
            if (!string.IsNullOrEmpty(a_Key))
            {
                Clientapikey? keyInfo = m_context.Clientapikeys.FirstOrDefault(k => k.Key == a_Key);
                if (keyInfo != null)
                {
                    if (keyInfo.IsActive == 0)
                    {
                        //Key is not active
                        return AuthEnums.Inactive;
                    }

                    if (TryDecodeKey(a_Key, out int businessId))
                    {
                        Contract? contract = m_context.Contracts.FirstOrDefault(c => c.ContractId == keyInfo.ContractId && c.BusinessId == businessId && c.StartDate <= DateTime.Now && c.EndDate > DateTime.Now);

                        if (contract == null)
                        {
                            contract = m_context.Contracts.FirstOrDefault(c => c.ContractId == keyInfo.ContractId && c.BusinessId == businessId);

                            //If contract start date is not past the key should inactive
                            if (contract?.StartDate > DateTime.Now)
                            {
                                return AuthEnums.Inactive;
                            }

                            //Anyother reason contract is expired
                            return AuthEnums.Expired;
                        }

                        //Key is valid and contract not expired
                        return AuthEnums.Valid;
                    }
                }
                else
                {
                    return AuthEnums.NotFound;
                }
            }

            return AuthEnums.Invalid;
        }

        public async Task<bool> GenerateKey(Contract a_clientContract)
        {
            const string prefix = "AI";
            const char delimiter = '@';
            const string chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

            StringBuilder key = new StringBuilder(32);
            key.Append(prefix);
            key.Append(a_clientContract.BusinessId);
            key.Append(delimiter);

            for (int i = key.Length; i < 32; i++)
            {
                key.Append(chars[m_random.Next(chars.Length)]);
            }

            Clientapikey clientapikey = new Clientapikey();
            clientapikey.Key = key.ToString();
            clientapikey.ContractId = a_clientContract.ContractId;

            m_context.Clientapikeys.Add(clientapikey);

            if (await m_context.SaveChangesAsync() > 0)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        public int? GetDatabaseIdFromKey(string a_Key)
        {
            if (ValidateKey(a_Key) == AuthEnums.Valid)
            {
                if (TryDecodeKey(a_Key, out int businessId))
                {
                    Clientapikey? keyInfo = m_context.Clientapikeys.FirstOrDefault(k => k.Key == a_Key);
                    Contract? contract = m_context.Contracts.FirstOrDefault(c => c.ContractId == keyInfo.ContractId && c.BusinessId == businessId && c.StartDate <= DateTime.Now && c.EndDate > DateTime.Now);

                    Databasemap? databaseMap = m_context.Databasemaps.FirstOrDefault(c => c.ClientId == contract.ClientId);

                    return databaseMap?.DbNo;
                }
            }
            return null;
        }

        public string GetBaseBranch(string a_Key)
        {
            if (ValidateKey(a_Key) == AuthEnums.Valid)
            {
                if (TryDecodeKey(a_Key, out int businessId))
                {
                    Clientapikey? keyInfo = m_context.Clientapikeys.FirstOrDefault(k => k.Key == a_Key);
                    Contract? contract = m_context.Contracts.FirstOrDefault(c => c.ContractId == keyInfo.ContractId && c.BusinessId == businessId && c.StartDate <= DateTime.Now && c.EndDate > DateTime.Now);

                    if (contract != null)
                    {
                        Clientbusiness? clientbusiness = m_context.Clientbusinesses.FirstOrDefault(cb => cb.ClientId == contract.ClientId && cb.BusinessId == businessId);
                        if (clientbusiness != null)
                        {
                            return clientbusiness.BusinessExternalId;
                        }
                    }
                }
            }
            return String.Empty;
        }
        public static bool TryDecodeKey(string a_key, out int o_businessId)
        {
            char delimiter = '@';
            o_businessId = 0;

            // Check if the key has the expected length and starts with the expected prefix
            if (a_key.Length == 32 && a_key.StartsWith("AI"))
            {
                // Find the index of the delimiter
                int delimiterIndex = a_key.IndexOf(delimiter, 2);

                // Check if the delimiter is found and there are characters after it
                if (delimiterIndex != -1 && delimiterIndex < a_key.Length - 1)
                {
                    // Attempt to parse the embedded integer value
                    if (int.TryParse(a_key.Substring(2, delimiterIndex - 2), out o_businessId))
                    {
                        return true; // Successfully decoded
                    }
                }
            }

            return false; // Failed to decode
        }
    }
}