using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.Common;
using System.Web;
using System.Configuration;
using System.Data.SqlClient;

namespace Bowin.Common.Linq.DB
{
    internal static class ConnectionCache
    {
        static ConnectionCache() 
        {
            IsGlobalConnectionStarted = false;
            ConnectionContexts = new Dictionary<string, DbConnection>();
        }

        public static bool IsGlobalConnectionStarted { get; set; }
        public static Dictionary<string, DbConnection> ConnectionContexts { get; set; }
    }

    public abstract class DbConnectionManager
    {
        public static bool IsGlobalConnectionStarted
        {
            get 
            {
                if (HttpContext.Current != null && HttpContext.Current.Session != null)
                {
                    return (bool)(HttpContext.Current.Session["IsGlobalConnectionStarted"] ?? false);
                }
                else
                {
                    return ConnectionCache.IsGlobalConnectionStarted;
                }
            }
            set
            {
                if (HttpContext.Current != null)
                {
                    HttpContext.Current.Session["IsGlobalConnectionStarted"] = value;
                }
                else
                {
                    ConnectionCache.IsGlobalConnectionStarted = value;
                }
            }
        }

        protected static bool ExistsConnection(string contextKey)
        {
            if (HttpContext.Current != null)
            {
                return HttpContext.Current.Session[contextKey] != null;
            }
            else
            {
                return ConnectionCache.ConnectionContexts[contextKey] != null;
            }
        }

        public static void AddConnection(string contextKey, DbConnection db)
        {
            if (HttpContext.Current != null)
            {
                HttpContext.Current.Session[contextKey] = db;
            }
            else
            {
                ConnectionCache.ConnectionContexts.Add(contextKey, db);
            }
        }

        public static void CloseConnections()
        {
            if (HttpContext.Current != null)
            {
                foreach (ConnectionStringSettings connectionSetting in System.Configuration.ConfigurationManager.ConnectionStrings)
                {
                    DbConnection db;

                    db = (DbConnection)HttpContext.Current.Session[connectionSetting.Name];

                    if (db != null)
                    {
                        if (db.State != System.Data.ConnectionState.Closed)
                        {
                            db.Close();
                        }
                    }
                }
            }
            else
            {
                foreach (var connection in ConnectionCache.ConnectionContexts)
                {
                    if (connection.Value.State != System.Data.ConnectionState.Closed)
                    {
                        connection.Value.Close();
                    }
                }
            }
        }

        public static void ClearConnection()
        {
            if (HttpContext.Current != null)
            {
                foreach (ConnectionStringSettings connectionSetting in System.Configuration.ConfigurationManager.ConnectionStrings)
                {
                    HttpContext.Current.Session[connectionSetting.Name] = null;
                }
            }
            else
            {
                ConnectionCache.ConnectionContexts = new Dictionary<string, DbConnection>();
            }

            IsGlobalConnectionStarted = false;
        }

        internal static DbConnection GetConnection(string contextKey)
        {
            if (HttpContext.Current != null)
            {
                return (DbConnection)HttpContext.Current.Session[contextKey];
            }
            else
            {
                return ConnectionCache.ConnectionContexts[contextKey];
            }
        }
    }
}