package guru.mikelue.jdut.vendor.mssql;
   
   import java.sql.Connection;
   import java.sql.SQLException;
   import java.util.Optional;
   
   import org.slf4j.Logger;
   import org.slf4j.LoggerFactory;
   
  import guru.mikelue.jdut.datagrain.DataRow;
  import guru.mikelue.jdut.datagrain.SchemaTable;
  import guru.mikelue.jdut.jdbc.JdbcTemplateFactory;
  import guru.mikelue.jdut.operation.DataRowOperator;
  
  /**
   * Used to surrounding {@link DataRowOperator} for supporting insertion of identity for table.
   */
  public class IdentityInsertOperator implements DataRowOperator {
  	private Logger logger = LoggerFactory.getLogger(IdentityInsertOperator.class);
  
  	/**
  	 * Used as flag to indicate the current data row has data of identity column.
  	 */
  	private final static String HAS_IDENTITY_COLUMN = "_mssql_has_identity_column_";
  
  	/**
  	 * Checks whether or not a data row has identity data.
  	 *
  	 * @param dataRow The data row to be checked
  	 *
  	 * @return true if it does
  	 */
  	public static boolean hasIdentityColumn(DataRow dataRow)
  	{
  		return dataRow.getAttribute(HAS_IDENTITY_COLUMN);
  	}
  	/**
  	 * Checks whether or not the table of data row has enabled identity.<br>
  	 *
  	 * If it is unknown, this method gives <em>true value</em>.
  	 *
  	 * @param dataRow The data row to be checked
  	 *
  	 * @return true if it does
  	 */
  	public static boolean identityChecked(DataRow dataRow)
  	{
  		return dataRow.hasAttribute(HAS_IDENTITY_COLUMN);
  	}
  
  	private final DataRowOperator op;
  
  	/**
  	 * As function interface of {@link DataRowOperator.SurroundOperator}.
  	 *
  	 * @param newOperator The operator to be surrounded
  	 *
  	 * @see DataRowOperator
  	 */
  	public IdentityInsertOperator(DataRowOperator newOperator)
  	{
  		op = newOperator;
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
  	public DataRowkelue/jdut/datagrain/DataRow.html#DataRow">DataRow operate(Connection connection, DataRow dataRow) throws SQLException
  	{
  		SchemaTable table = dataRow.getTable();
  
  		/**
  		 * Initialize flags for identity data
  		 */
  		if (!identityChecked(dataRow)) {
  			dataRow.putAttribute(
  				HAS_IDENTITY_COLUMN,
  				dataRow.getColumns().stream()
  					.anyMatch(columnName -> {
  						Optional<Boolean> autoIncremental = table.getColumn(columnName).getAutoIncremental();
  						return autoIncremental.isPresent() && autoIncremental.get();
  					})
  			);
  		}
  		// :~)
  
  		/**
  		 * Executes the enabled identity insert command to the table
  		 */
  		if (hasIdentityColumn(dataRow)) {
  			JdbcTemplateFactory.buildRunnable(
  				() -> connection.createStatement(),
  				stat -> stat.executeUpdate(String.format(
  					"SET IDENTITY_INSERT %s ON",
  					table.getQuotedFullName()
  				))
  			).runJdbc();
  		}
 		// :~)
 
 		DataRow result = op.operate(connection, dataRow);
 
 		/**
 		 * Disable identity insert
 		 */
 		if (hasIdentityColumn(dataRow)) {
 			logger.debug("[MS SQL Server] Enable identity: \"{}\"", table.getName());
 			JdbcTemplateFactory.buildRunnable(
 				() -> connection.createStatement(),
 				stat -> stat.executeUpdate(String.format(
 					"SET IDENTITY_INSERT %s OFF",
 					table.getQuotedFullName()
 				))
 			).runJdbc();
 		}
 		// :~)
 
 		return result;
 	}
 }