/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008-2011, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.id.enhanced;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

import org.hibernate.HibernateException;
import org.hibernate.LockMode;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.jdbc.internal.FormatStyle;
import org.hibernate.engine.jdbc.spi.JdbcServices;
import org.hibernate.engine.jdbc.spi.SqlStatementLogger;
import org.hibernate.engine.spi.SessionEventListenerManager;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.id.IdentifierGenerationException;
import org.hibernate.id.IdentifierGeneratorHelper;
import org.hibernate.id.IntegralDataTypeHolder;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.jdbc.AbstractReturningWork;

import org.jboss.logging.Logger;

Describes a table used to mimic sequence behavior
Author:
Steve Ebersole/**
 * Describes a table used to mimic sequence behavior
 *
 * @author Steve Ebersole
 */
public class TableStructure implements DatabaseStructure {
	private static final CoreMessageLogger LOG = Logger.getMessageLogger(
			CoreMessageLogger.class,
			TableStructure.class.getName()
	);

	private final String tableName;
	private final String valueColumnName;
	private final int initialValue;
	private final int incrementSize;
	private final Class numberType;
	private final String selectQuery;
	private final String updateQuery;

	private boolean applyIncrementSizeToSourceValues;
	private int accessCounter;

	public TableStructure(
			Dialect dialect,
			String tableName,
			String valueColumnName,
			int initialValue,
			int incrementSize,
			Class numberType) {
		this.tableName = tableName;
		this.initialValue = initialValue;
		this.incrementSize = incrementSize;
		this.valueColumnName = valueColumnName;
		this.numberType = numberType;

		selectQuery = "select " + valueColumnName + " as id_val" +
				" from " + dialect.appendLockHint( LockMode.PESSIMISTIC_WRITE, tableName ) +
				dialect.getForUpdateString();

		updateQuery = "update " + tableName +
				" set " + valueColumnName + "= ?" +
				" where " + valueColumnName + "=?";
	}

	@Override
	public String getName() {
		return tableName;
	}

	@Override
	public int getInitialValue() {
		return initialValue;
	}

	@Override
	public int getIncrementSize() {
		return incrementSize;
	}

	@Override
	public int getTimesAccessed() {
		return accessCounter;
	}

	@Override
	public void prepare(Optimizer optimizer) {
		applyIncrementSizeToSourceValues = optimizer.applyIncrementSizeToSourceValues();
	}

	private IntegralDataTypeHolder makeValue() {
		return IdentifierGeneratorHelper.getIntegralDataTypeHolder( numberType );
	}

	@Override
	public AccessCallback buildCallback(final SessionImplementor session) {
		final SqlStatementLogger statementLogger = session.getFactory().getServiceRegistry()
				.getService( JdbcServices.class )
				.getSqlStatementLogger();
		final SessionEventListenerManager statsCollector = session.getEventListenerManager();

		return new AccessCallback() {
			@Override
			public IntegralDataTypeHolder getNextValue() {
				return session.getTransactionCoordinator().getTransaction().createIsolationDelegate().delegateWork(
						new AbstractReturningWork<IntegralDataTypeHolder>() {
							@Override
							public IntegralDataTypeHolder execute(Connection connection) throws SQLException {
								final IntegralDataTypeHolder value = makeValue();
								int rows;
								do {
									final PreparedStatement selectStatement = prepareStatement( connection, selectQuery, statementLogger, statsCollector );
									try {
										final ResultSet selectRS = executeQuery( selectStatement, statsCollector );
										if ( !selectRS.next() ) {
											final String err = "could not read a hi value - you need to populate the table: " + tableName;
											LOG.error( err );
											throw new IdentifierGenerationException( err );
										}
										value.initialize( selectRS, 1 );
										selectRS.close();
									}
									catch (SQLException sqle) {
										LOG.error( "could not read a hi value", sqle );
										throw sqle;
									}
									finally {
										selectStatement.close();
									}


									final PreparedStatement updatePS = prepareStatement( connection, updateQuery, statementLogger, statsCollector );
									try {
										final int increment = applyIncrementSizeToSourceValues ? incrementSize : 1;
										final IntegralDataTypeHolder updateValue = value.copy().add( increment );
										updateValue.bind( updatePS, 1 );
										value.bind( updatePS, 2 );
										rows = executeUpdate( updatePS, statsCollector );
									}
									catch (SQLException e) {
										LOG.unableToUpdateQueryHiValue( tableName, e );
										throw e;
									}
									finally {
										updatePS.close();
									}
								} while ( rows == 0 );

								accessCounter++;

								return value;
							}
						},
						true
				);
			}

			@Override
			public String getTenantIdentifier() {
				return session.getTenantIdentifier();
			}
		};
	}

	private PreparedStatement prepareStatement(
			Connection connection,
			String sql,
			SqlStatementLogger statementLogger,
			SessionEventListenerManager statsCollector) throws SQLException {
		statementLogger.logStatement( sql, FormatStyle.BASIC.getFormatter() );
		try {
			statsCollector.jdbcPrepareStatementStart();
			return connection.prepareStatement( sql );
		}
		finally {
			statsCollector.jdbcPrepareStatementEnd();
		}
	}

	private int executeUpdate(PreparedStatement ps, SessionEventListenerManager statsCollector) throws SQLException {
		try {
			statsCollector.jdbcExecuteStatementStart();
			return ps.executeUpdate();
		}
		finally {
			statsCollector.jdbcExecuteStatementEnd();
		}

	}

	private ResultSet executeQuery(PreparedStatement ps, SessionEventListenerManager statsCollector) throws SQLException {
		try {
			statsCollector.jdbcExecuteStatementStart();
			return ps.executeQuery();
		}
		finally {
			statsCollector.jdbcExecuteStatementEnd();
		}
	}

	@Override
	public String[] sqlCreateStrings(Dialect dialect) throws HibernateException {
		return new String[] {
				dialect.getCreateTableString() + " " + tableName + " ( " + valueColumnName + " " + dialect.getTypeName( Types.BIGINT ) + " )",
				"insert into " + tableName + " values ( " + initialValue + " )"
		};
	}

	@Override
	public String[] sqlDropStrings(Dialect dialect) throws HibernateException {
		return new String[] { dialect.getDropTableString( tableName ) };
	}

	@Override
	public boolean isPhysicalSequence() {
		return false;
	}
}