namespace bts.SilverPine {
   using System;
   using System.Data;
   using System.Data.SQLite;
   using System.Diagnostics;
   using System.Collections;


   using BCG;

   [DataStreamUserRespresentation("SQLite")]
   public class SQLiteStream : ViewStream {
      private readonly string _connection_string, _query;
      private Stopwatch _stopwatch = new Stopwatch();

      private SQLiteStream(string connection_string, string query, bool noop) {
         _connection_string = connection_string;
         _query = query;
      }

      public SQLiteStream(string db_name, string query)
      :
      this($"Data Source={SQLiteHelper.location}{db_name};Version=3", query, true) { }

      public SQLiteStream(string query)
      :
      this(SQLiteHelper.db_name, query) {
      }


      private void _read_from_sqlite_and_fire() {
         _stopwatch.Start();
         DataTable dt = SQLiteHelper.execute_select_query(_connection_string, _query);
         _stopwatch.Stop();
         Log.Gen.info($"SQLiteStream.ExecuteSelectQuery time to read db: {_stopwatch.ElapsedMilliseconds} msecs");
         _stopwatch.Restart();
         #region perf measures
         // SQLiteHelper.get_table(_connection_string, _query);
         // _stopwatch.Stop();
         // Log.Gen.info($"SQLiteStream.get_table time to read db: {_stopwatch.ElapsedMilliseconds} msecs");
         // _stopwatch.Restart();
         // SQLiteHelper.ExecuteBulkRead(_connection_string, _query);
         // _stopwatch.Stop();
         // Log.Gen.info($"SQLiteStream.ExecuteBulkRead time to read db: {_stopwatch.ElapsedMilliseconds} msecs");
         // _stopwatch.Restart();
         // SQLiteHelper.get_table_2(_connection_string, _query);
         // _stopwatch.Stop();
         // Log.Gen.info($"SQLiteStream.get_table_2 time to read db: {_stopwatch.ElapsedMilliseconds} msecs");
         // _stopwatch.Restart();
         #endregion
         IBlueRowCollection rows = BCG.BlueDataUtility.toIBlueRowCollection(dt);
         //IBlueRowCollection rows = new DataTableWrapperTable(dt);
         _stopwatch.Stop();
         Log.Gen.info($"SQLiteStream._read_from_sqlite_and_fire time to load into IBlueRowCollection: {_stopwatch.ElapsedMilliseconds} msecs");
         DataPacket dp = BlueDataUtility.build_dp_inc(rows, myLastValue as DataPacket);
         myFireEvent(dp);
      }

      protected override void myOnFirstSubscriber() {
         _read_from_sqlite_and_fire();
      }

      protected override void myOnLastSubscriber() {
         // this value will be cleared by the base class
         // but in this particular stream this behaviour
         // is not usefull since any new subscribers 
         // would force the query to be recreated
         //myLastDP = myLastValue;
      }

   }

}