Adds option pattern for smart config

Core/Configurations/SmartConfigProvider/SmartConfigProvider.cs

@@ -0,0 +1,75 @@
+using Core.Configurations.JsonConfigProvider;
+using Core.Exceptions;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+
+namespace Core.Configurations.SmartConfig
+{
+    public class SmartConfigProvider : IConfigurationProvider
+    {
+        string _configKey;
+        string _connectionString;
+        string _path;
+        IConfigurationBuilder _builder;
+
+        Newtonsoft.Json.Linq.JObject _configuration;
+        SmartConfigOptions _smartConfigOptions;
+
+        public SmartConfigProvider() { }
+
+        public SmartConfigProvider(IConfigurationBuilder builder, SmartConfigOptions smartConfigOptions)
+        {
+            _builder = builder;
+            _smartConfigOptions = smartConfigOptions;
+            _configKey = smartConfigOptions._configKey;
+            SetConnectionString();
+
+        }
+        public SmartConfigProvider(IConfigurationBuilder builder, string configKey, string configurationFilePath)
+        {
+            _builder = builder;
+            _configKey = configKey;
+            _path = configurationFilePath;
+            SetConnectionString();
+        }
+
+        void SetConnectionString()
+        {
+            var carrier = _builder.ConfigurationProviders.OfType<IHasConfigurationFilePath>().SingleOrDefault();
+
+            if (carrier?.ConfigurationFilePath is null && _path is null)
+                throw new ConfigurationException($"Expected a previous added ConfigurationProvider with IHasConfigurationFilePath or a configurationFilePath where to find the appsettingsfile");
+
+            _path ??= carrier.ConfigurationFilePath;
+
+            if (!File.Exists(_path))
+                throw new ConfigurationException($"File not found, configurationFilePath: {_path}");
+
+
+            using (StreamReader file = File.OpenText(_path))
+            using (JsonTextReader reader = new JsonTextReader(file))
+            {
+                var jsonConfiguration = (Newtonsoft.Json.Linq.JObject)Newtonsoft.Json.Linq.JToken.ReadFrom(reader);
+
+                _connectionString = jsonConfiguration.SelectToken($"ConnectionStrings.{_configKey}")?.ToString();
+            }
+        }
+        public void Build()
+        {
+            var repository = _smartConfigOptions.GetRepository();
+            repository.ConnectionString = _connectionString;
+
+            var configs = repository.GetActiveConfigurations();
+
+            var pairs = configs.Select(x => new KeyValuePair<string, JToken>(x.Key, JToken.Parse(x.Value.ToString())));
+
+            _configuration = Common.KeyValueToJson.Convert(pairs);
+
+        }
+
+        public Newtonsoft.Json.Linq.JObject Configuration()
+        {
+            return _configuration;
+        }
+    }
+}