package org.kuali.common.impex.data.impl.mysql;
   
   import java.io.BufferedReader;
   import java.io.IOException;
   import java.text.SimpleDateFormat;
   import java.util.ArrayList;
   import java.util.Collections;
   import java.util.List;
   
  import org.apache.commons.lang3.StringUtils;
  import org.kuali.common.impex.data.MpxHeaderData;
  import org.kuali.common.impex.data.impl.AbstractSqlProducer;
  import org.kuali.common.impex.data.impl.DataBean;
  import org.kuali.common.impex.data.impl.MpxParser;
  import org.kuali.common.impex.model.Column;
  import org.kuali.common.impex.model.Table;
  import org.kuali.common.util.CollectionUtils;
  
  public class MySqlProducer extends AbstractSqlProducer {
  
      public static final String SUPPORTED_VENDOR = "mysql";
  
      private static final String BATCH_SEPARATOR = ",";
      private static final String ARG_LIST_START = "(";
      private static final String ARG_LIST_END = ")";
      private static final String SPACE = " ";
  
      private static final String DATE_VALUE_PREFIX = "STR_TO_DATE('";
      public static final String DATE_VALUE_SUFFIX = "','%Y%m%d%H%i%s')";
  
      private static final String PREFIX_START = "INSERT INTO ";
      private static final String PREFIX_END = " VALUES ";
  
      /**
       * Read data lines from the .mpx file and combine them into batched up, INSERT INTO sql statements. Individual data lines are merged together into SQL statements 50 lines at a
       * time or 50K in length whichever comes first.
       */
      @Override
      public List<String> getSql(Table table, MpxHeaderData headerData, BufferedReader reader) throws IOException {
  
          // Extract the columns into a list
          List<Column> columns = table.getColumns();
  
          // Setup some storage
          StringBuilder sb = new StringBuilder();
  
          // INSERT INTO FOO (BAR1,BAR2) VALUES
          sb.append(getPrefix(table, headerData));
  
          // Track rows processed
          int rows = 0;
  
          // read the first line
          String line = reader.readLine();
  
          // Iterate through the .mpx file
          for (; ; ) {
  
              // We hit the end of the .mpx file
              if (line == null) {
                  break;
              }
  
              List<DataBean> rowBeans = buildRowData(columns, MpxParser.parseMpxLine(line), headerData);
  
              if (rows != 0) {
                  // Need to add a comma, unless this is the first set of values
                  sb.append(BATCH_SEPARATOR);
              }
  
              sb.append(buildBatchSql(rowBeans));
  
              // increment our counters
              rows++;
  
              // Have we exceeded any of our limits?
              if (batchLimitReached(rows, sb.length())) {
                  break;
              }
  
              // read the next line and start the loop over
              line = reader.readLine();
          }
  
          // return null to indicate no rows were processed
          if (rows == 0) {
              return null;
          } else {
              return Collections.singletonList(sb.toString());
          }
      }
  
      protected String buildBatchSql(List<DataBean> rowBeans) {
          StringBuilder batchBuilder = new StringBuilder();
          SimpleDateFormat sqlDateFormatter = new SimpleDateFormat(OUTPUT_DATE_FORMAT);
          List<String> sqlValues = new ArrayList<String>(rowBeans.size());
          for (DataBean d : rowBeans) {
              sqlValues.add(getSqlValue(d, sqlDateFormatter));
          }
         batchBuilder.append(ARG_LIST_START);
         batchBuilder.append(CollectionUtils.getCSV(sqlValues));
         batchBuilder.append(ARG_LIST_END);
         return batchBuilder.toString();
     }
 
     protected String getSqlValue(DataBean data, SimpleDateFormat dateFormat) {
         StringBuilder result = new StringBuilder();
 
         if (data.getDateValue() != null) {
             result.append(DATE_VALUE_PREFIX);
             result.append(dateFormat.format(data.getDateValue()));
             result.append(DATE_VALUE_SUFFIX);
         } else {
             result.append(data.getValue());
         }
 
         return result.toString();
     }
 
     // INSERT INTO FOO (BAR1,BAR2) VALUES
     protected String getPrefix(Table table, MpxHeaderData headerData) {
         String columnNamesCSV = CollectionUtils.getCSV(headerData.getColumnNames());
         StringBuilder sb = new StringBuilder();
         sb.append(PREFIX_START).append(table.getName()).append(SPACE);
         sb.append(ARG_LIST_START).append(columnNamesCSV).append(ARG_LIST_END);
         sb.append(PREFIX_END);
         return sb.toString();
     }
 
     @Override
     protected String getEscapedValue(Column column, String token) {
         String escaped1 = StringUtils.replace(token, "\\", "\\\\");
         String escaped2 = StringUtils.replace(escaped1, "'", "\\'");
         String escaped3 = StringUtils.replace(escaped2, "\n", "\\n");
         return "'" + escaped3 + "'";
     }
 }