// This Source Code is in the Public Domain per: http://litesoft.org/License.txt
package org.litesoft.sql.statements;

import java.sql.*;

import org.litesoft.db.*;
import org.litesoft.logger.*;
import org.litesoft.logger.nonpublic.*;
import org.litesoft.sql.*;

public class JDBCexecuteQuery extends JDBCexecutor implements DisposableResultSetIterator
{
    private static final Logger LOGGER = LoggerFactory.getLogger( JDBCexecuteQuery.class );

    private ResultSet mResultSet = null;
    private Boolean mRSnext = null;

    public JDBCexecuteQuery( SQLPersistenceHelper pPersistenceHelper, DBconnection pDBconnection, String pCmd, Object pLoggingContext )
    {
        super( pPersistenceHelper, pDBconnection, pCmd, pLoggingContext );
    }

    public JDBCexecuteQuery( SQLPersistenceHelper pPersistenceHelper, String pCmd, Object pLoggingContext )
    {
        super( pPersistenceHelper, pCmd, pLoggingContext );
    }

    private void closeResultSet()
    {
        if ( mResultSet != null )
        {
            try
            {
                mResultSet.close();
            }
            catch ( SQLException eatit )
            {
                // Whatever...
                logException( mCmd, eatit );
            }
            finally
            {
                mResultSet = null;
            }
        }
    }

    @Override
    protected void releaseResources()
    {
        mRSnext = Boolean.FALSE;
        closeResultSet();
        super.releaseResources();
    }

    public JDBCexecuteQuery executeQuery()
            throws DBException
    {
        logCommand( mCmd );
        try
        {
            mResultSet = getStatement().executeQuery( mCmd );
        }
        catch ( SQLException e )
        {
            releaseResources();
            throw new WrappedSQLException( mCmd, e );
        }
        return this;
    }

    private boolean areRSnext()
            throws SQLException
    {
        if ( mRSnext == null )
        {
            if ( mResultSet.next() )
            {
                mRSnext = Boolean.TRUE;
            }
            else
            {
                releaseResources(); // Sets: mRSnext = false
            }
        }
        return mRSnext;
    }

    @Override
    public boolean hasNext()
    {
        try
        {
            return areRSnext();
        }
        catch ( SQLException e )
        {
            logException( mCmd, e );
            releaseResources(); // Sets: mRSnext = false
            throw new WrappedSQLException( mCmd, e );
        }
    }

    @Override
    public ResultSet next()
    {
        if ( !hasNext() )
        {
            return null;
        }
        mRSnext = null;
        return mResultSet;
    }

    public ResultSetMetaData getMetaData()
    {
        try
        {
            return mResultSet.getMetaData();
        }
        catch ( SQLException e )
        {
            logException( mCmd, e );
            releaseResources(); // Sets: mRSnext = false
            throw new WrappedSQLException( mCmd, e );
        }
    }

    public int getResultSetColumnCount()
    {
        try
        {
            return getMetaData().getColumnCount();
        }
        catch ( SQLException e )
        {
            logException( mCmd, e );
            releaseResources(); // Sets: mRSnext = false
            throw new WrappedSQLException( mCmd, e );
        }
    }

    @Override
    public void remove()
    {
        throw new UnsupportedOperationException( "Can not 'remove' from ResultSet Iterator" );
    }

    /**
     * Logs the pCmd String at "TRACE" or "DEBUG" level.
     *
     * @param pCmd
     */
    @SuppressWarnings({"ThrowableInstanceNeverThrown"}) @Override
    protected void logCommand( String pCmd )
    {
        AbstractLogger zLogger = LOGGER.trace();
        if ( zLogger.isEnabled() )
        {
            zLogger.log( new Exception(), pCmd, "; | ", mLoggingContext );
            return;
        }
        zLogger = LOGGER.debug();
        if ( zLogger.isEnabled() )
        {
            zLogger.log( pCmd, "; | ", mLoggingContext );
        }
        else
        {
            super.logCommand( pCmd );
        }
    }
}