using System;
using System.Diagnostics;
using System.IO;

using BCG.Utilities.General;

namespace BCG
{
   [DataStreamUserRespresentation("textWriter")]
   public class TextWriterStream : ViewStream, IWorker
   {
      #region constructor
      public TextWriterStream(ViewStream stream, string fileNamePrefix, int writeFreqSecs)
         : this(ViewStreamDatabase.instance, stream, fileNamePrefix, writeFreqSecs)
      {
      }

      public TextWriterStream(ViewStreamDatabase vsd, ViewStream stream, string fileNamePrefix, int writeFreqSecs)
      {
         myVsd            = vsd;
         myStream         = stream;
         myFileNamePrefix = fileNamePrefix;
         myWriteFreqSecs  = writeFreqSecs;
         myNextWrite      = DateTime.MinValue;
         myGotUpdate      = false;
         mySchemaStr      = null;

         if (!myFileNamePrefix.EndsWith("_"))
         {
            myFileNamePrefix += "_";
         }
      }
      #endregion

      #region ViewStream
      protected override void myOnFirstSubscriber()
      {
         myStream.onChange += myStreamChange;
         myVsd.addWorker(this);
      }

      protected override void  myOnLastSubscriber()
      {
         myVsd.removeWorker(this);
         myStream.onChange -= myStreamChange;
      }
      #endregion

      #region IWorker
      public void doWork()
      {
         if ((myNextWrite <= DateTime.Now && myGotUpdate))
         {
            myGotUpdate = false;
            myNextWrite = DateTime.Now.AddSeconds(myWriteFreqSecs);
            myWrite(myStream.rows);
         }
      }
      #endregion

      private void myStreamChange(object o)
      {
         myGotUpdate = true;
      }

      #region helpers
      public void myWrite(IBlueRowCollection rows)
      {
         #region create schema str
         if (mySchemaStr == null)
         {
            myCreateSchemaStr(rows.schema);
         }
         #endregion

         // create file name
         string filename = String.Format("{0}{1}.txt", myFileNamePrefix, myDateTimeStr(DateTime.Now));

         // open file
         StreamWriter writer = new StreamWriter(filename);

         // write schema str
         if (mySchemaStr != null)
         {
            writer.WriteLine(mySchemaStr);
         }

         foreach (IBlueRow row in rows)
         {
            #region write row str
            string rowStr = "";
            foreach (string columnName in row.schema.columnNames)
            {
               if (rowStr != "")
               {
                  rowStr += DELIM;
               }

               rowStr += row[columnName].ToString();
            }

            writer.WriteLine(rowStr);
            #endregion
         }

         // close file
         writer.Close();
      }

      public void myCreateSchemaStr(IBlueTableSchema schema)
      {
         mySchemaStr = "";

         foreach (ColumnInfo columnInfo in schema.columnInfo)
         {
            if (mySchemaStr != "")
            {
               mySchemaStr += DELIM;
            }

            mySchemaStr += String.Format("{0}:{1}", columnInfo.colName, columnInfo.colType.ToString());
         }
      }

      private string myDateTimeStr(DateTime dateTime)
      {
         return (String.Format("{0}{1}{2}{3}{4}{5}",
             dateTime.Year.ToString("D4"), dateTime.Month.ToString("D2"), dateTime.Day.ToString("D2"),
             dateTime.Hour.ToString("D2"), dateTime.Minute.ToString("D2"), dateTime.Second.ToString("D2")));
      }
      #endregion

      public static readonly string DELIM = ", ";

      #region state
      private ViewStreamDatabase myVsd;
      private ViewStream         myStream;
      private string             myFileNamePrefix;
      private int                myWriteFreqSecs;
      private DateTime           myNextWrite;
      private bool               myGotUpdate;
      private string             mySchemaStr;
      #endregion
   }
}