using System;
using System.Collections.Generic;
using System.Data.Common;
using System.IO;
using System.Reflection;

namespace Mesnac.Codd.Session
{
    public class DbSession : IDisposable
    {
        public DbSession(DbProviderFactory factory, string connstr)
        {
            this.ConnectionString = connstr;
            this.ProviderFactory = factory;
        }
        public string ConnectionString { get; set; }
        public DbProviderFactory ProviderFactory { get; set; }
        private DbConnection _connection = null;
        public DbConnection Connection
        {
            get
            {
                if (_connection == null)
                {
                    this._connection = this.ProviderFactory.CreateConnection();
                    this._connection.ConnectionString = this.ConnectionString;
                }
                return _connection;
            }
        }
        private DbCommand _command = null;
        public DbCommand Command
        {
            get
            {
                if (_command == null)
                {
                    this._command = this.ProviderFactory.CreateCommand();
                    this._command.Connection = this.Connection;
                    this._command.CommandType = System.Data.CommandType.Text;
                }
                return _command;
            }
        }

        public void Close()
        {
            try
            {
                this.Connection.Close();
                this.Connection.Dispose();
                this.Command.Dispose();
            }
            catch { }
            finally
            {
                this._connection = null;
                this._command = null;
            }
        }
        public void Dispose()
        {
            this.Close();
            this.ProviderFactory = null;
        }
    }

    public static class DbSessionFactory
    {
        private static Dictionary<string, DbSession> dbSessionFactoryList = new Dictionary<string, DbSession>();
        public static DbSession GetDbSession(string connectionString)
        {
            DbSession session = null;
            if (!dbSessionFactoryList.TryGetValue(connectionString, out session))
            {
                DbProviderFactory factory = System.Data.SqlClient.SqlClientFactory.Instance;
                session = new DbSession(factory, connectionString);
                dbSessionFactoryList.Add(connectionString, session);
            }
            return session;
        }
    }
}