using System;
using System.Collections;
using System.Data.Common;
using System.Data.SqlClient;
using System.Data.EntityClient;


namespace Test05
{
    class Program
    {
        static void Main(string[] args)
        {
            // Build an entity connection string from scratch
            string entityString1 = ConnectionStringBuilder.BuildEntityConnectionString();
            Console.WriteLine("\n\n------------------- BUILT ----------------\n");
            Console.WriteLine(entityString1);

            // Load an entity connection string from the app.config
            string entityString2 = ConnectionStringLoader.LoadEntityConnectionString();
            Console.WriteLine("\n\n------------------- LOADED ----------------\n");
            Console.WriteLine(entityString2);
        }
    }


    class ConnectionStringBuilder
    {
        internal static string BuildEntityConnectionString()
        {
            EntityConnectionStringBuilder entityBuilder = new EntityConnectionStringBuilder();

            entityBuilder.Provider = Util.ReadKeyValue("Provider");
            entityBuilder.Metadata = Util.ReadKeyValue("Metadata");
            entityBuilder.ProviderConnectionString = BuildDbConnectionString(entityBuilder.Provider);

            return entityBuilder.ToString();
        }


        static string BuildDbConnectionString(string provider)
        {
            // We may not know what provider we are dealing with, so let's be generic.
            DbProviderFactory dbFactory = DbProviderFactories.GetFactory(provider);
            DbConnectionStringBuilder dbBuilder = dbFactory.CreateConnectionStringBuilder();

            // Allow the user to enter value for each keyword
            foreach (string key in dbBuilder.Keys)
            {
                dbBuilder.Add(key, Util.ReadKeyValue(key));
            }

            return dbBuilder.ToString();
        }
    }


    class ConnectionStringLoader
    {
        internal static string LoadEntityConnectionString()
        {
            EntityConnectionStringBuilder entityBuilder = new EntityConnectionStringBuilder();

            entityBuilder.Name = Util.ReadKeyValue("Name");

            return entityBuilder.ToString();
        }
    }


    class Util
    {
        internal static string ReadKeyValue(string key)
        {
            string value = null;

            Console.Write("{0}=", key);
            value = Console.ReadLine();

            if (string.IsNullOrEmpty(value))
            {
                value = null;
            }

            return value;
        }
    }    
}