/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.sql;
import org.hibernate.LockMode;
import org.hibernate.LockOptions;
import org.hibernate.dialect.Dialect;
import org.hibernate.internal.util.StringHelper;


/**
 * A simple SQL <tt>SELECT</tt> statement
 * @author Gavin King
 */
public class Select {

	protected String selectClause;
	protected String fromClause;
	protected String outerJoinsAfterFrom;
	protected String whereClause;
	protected String outerJoinsAfterWhere;
	protected String orderByClause;
	protected String groupByClause;
	protected String comment;

	protected LockOptions lockOptions = new LockOptions();

	public final Dialect dialect;

	private int guesstimatedBufferSize = 20;
	
	public Select(Dialect dialect) {
		this.dialect = dialect;
	}

	/**
	 * Construct an SQL <tt>SELECT</tt> statement from the given clauses
	 */
	public String toStatementString() {
		StringBuilder buf = new StringBuilder(guesstimatedBufferSize);
		if ( StringHelper.isNotEmpty(comment) ) {
			buf.append( "/* " ).append( Dialect.escapeComment( comment ) ).append( " */ " );
		}
		
		buf.append("select ").append(selectClause)
				.append(" from ").append(fromClause);
		
		if ( StringHelper.isNotEmpty(outerJoinsAfterFrom) ) {
			buf.append(outerJoinsAfterFrom);
		}
		
		if ( StringHelper.isNotEmpty(whereClause) || StringHelper.isNotEmpty(outerJoinsAfterWhere) ) {
			buf.append(" where " );
			// the outerJoinsAfterWhere needs to come before where clause to properly
			// handle dynamic filters
			if ( StringHelper.isNotEmpty(outerJoinsAfterWhere) ) {
				buf.append(outerJoinsAfterWhere);
				if ( StringHelper.isNotEmpty(whereClause) ) {
					buf.append( " and " );
				}
			}
			if ( StringHelper.isNotEmpty( whereClause ) ) {
				buf.append(whereClause);
			}
		}
		
		if ( StringHelper.isNotEmpty(groupByClause) ) {
			buf.append(" group by ").append(groupByClause);
		}
		
		if ( StringHelper.isNotEmpty(orderByClause) ) {
			buf.append(" order by ").append(orderByClause);
		}
		
		if (lockOptions.getLockMode() != LockMode.NONE) {
			buf.append(dialect.getForUpdateString(lockOptions));
		}
		
		return dialect.transformSelectString( buf.toString() );
	}

	/**
	 * Sets the fromClause.
	 * @param fromClause The fromClause to set
	 */
	public Select setFromClause(String fromClause) {
		this.fromClause = fromClause;
		this.guesstimatedBufferSize += fromClause.length();
		return this;
	}

	public Select setFromClause(String tableName, String alias) {
		this.fromClause = tableName + ' ' + alias;
		this.guesstimatedBufferSize += fromClause.length();
		return this;
	}

	public Select setOrderByClause(String orderByClause) {
		this.orderByClause = orderByClause;
		this.guesstimatedBufferSize += orderByClause.length();
		return this;
	}

	public Select setGroupByClause(String groupByClause) {
		this.groupByClause = groupByClause;
		this.guesstimatedBufferSize += groupByClause.length();
		return this;
	}

	public Select setOuterJoins(String outerJoinsAfterFrom, String outerJoinsAfterWhere) {
		this.outerJoinsAfterFrom = outerJoinsAfterFrom;

		// strip off any leading 'and' token
		String tmpOuterJoinsAfterWhere = outerJoinsAfterWhere.trim();
		if ( tmpOuterJoinsAfterWhere.startsWith("and") ) {
			tmpOuterJoinsAfterWhere = tmpOuterJoinsAfterWhere.substring(4);
		}
		this.outerJoinsAfterWhere = tmpOuterJoinsAfterWhere;

		this.guesstimatedBufferSize += outerJoinsAfterFrom.length() + outerJoinsAfterWhere.length();
		return this;
	}


	/**
	 * Sets the selectClause.
	 * @param selectClause The selectClause to set
	 */
	public Select setSelectClause(String selectClause) {
		this.selectClause = selectClause;
		this.guesstimatedBufferSize += selectClause.length();
		return this;
	}

	public Select setSelectClause(SelectFragment selectFragment) {
		setSelectClause( selectFragment.toFragmentString().substring( 2 ) );
		return this;
	}

	/**
	 * Sets the whereClause.
	 * @param whereClause The whereClause to set
	 */
	public Select setWhereClause(String whereClause) {
		this.whereClause = whereClause;
		this.guesstimatedBufferSize += whereClause.length();
		return this;
	}

	public Select setComment(String comment) {
		this.comment = comment;
		this.guesstimatedBufferSize += comment.length();
		return this;
	}

	/**
	 * Get the current lock mode
	 * @return LockMode
	 * @deprecated Instead use getLockOptions
	 */
	@Deprecated
	public LockMode getLockMode() {
		return lockOptions.getLockMode();
	}

	/**
	 * Set the lock mode
	 * @param lockMode
	 * @return this object
	 * @deprecated Instead use setLockOptions
	 */
	@Deprecated
	public Select setLockMode(LockMode lockMode) {
		lockOptions.setLockMode(lockMode);
		return this;
	}

	/**
	 * Get the current lock options
	 * @return LockOptions
	 */
	public LockOptions getLockOptions() {
		return lockOptions;
	}

	/**
	 * Set the lock options
	 * @param lockOptions
	 * @return this object
	 */
	public Select setLockOptions(LockOptions lockOptions) {
		LockOptions.copy(lockOptions, this.lockOptions);
		return this;
	}
}
