package org.jumpmind.db.alter;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import org.jumpmind.db.model.Column;
import org.jumpmind.db.model.Database;
import org.jumpmind.db.model.Table;
import org.jumpmind.db.platform.DdlException;

/**
 * Represents the addition of a column to a table.
 */
public class AddColumnChange extends TableChangeImplBase
{
    /** The new column. */
    private Column _newColumn;
    /** The column after which the new column should be added. */
    private Column _previousColumn;
    /** The column before which the new column should be added. */
    private Column _nextColumn;
    /** Whether the column is added at the end. */
    private boolean _atEnd;

    /**
     * Creates a new change object.
     * 
     * @param table          The table to add the column to
     * @param newColumn      The new column
     * @param previousColumn The column after which the new column should be added
     * @param nextColumn     The column before which the new column should be added
     */
    public AddColumnChange(Table table, Column newColumn, Column previousColumn, Column nextColumn)
    {
        super(table);
        _newColumn      = newColumn;
        _previousColumn = previousColumn;
        _nextColumn     = nextColumn;
    }

    /**
     * Returns the new column.
     *
     * @return The new column
     */
    public Column getNewColumn()
    {
        return _newColumn;
    }

    /**
     * Returns the column after which the new column should be added.
     *
     * @return The previous column
     */
    public Column getPreviousColumn()
    {
        return _previousColumn;
    }

    /**
     * Returns the column before which the new column should be added.
     *
     * @return The next column
     */
    public Column getNextColumn()
    {
        return _nextColumn;
    }

    /**
     * Determines whether the column is added at the end (when applied in the order
     * of creation of the changes).
     * 
     * @return <code>true</code> if the column is added at the end
     */
    public boolean isAtEnd()
    {
        return _atEnd;
    }

    /**
     * Specifies whether the column is added at the end (when applied in the order
     * of creation of the changes).
     * 
     * @param atEnd <code>true</code> if the column is added at the end
     */
    public void setAtEnd(boolean atEnd)
    {
        _atEnd = atEnd;
    }

    /**
     * {@inheritDoc}
     */
    public void apply(Database database, boolean caseSensitive)
    {
        Column newColumn = null;

        try
        {
            newColumn = (Column)_newColumn.clone();
        }
        catch (CloneNotSupportedException ex)
        {
            throw new DdlException(ex);
        }

        Table table = database.findTable(getChangedTable().getName(), caseSensitive);

        if ((_previousColumn != null) && (_nextColumn != null))
        {
            int idx = table.getColumnIndex(_previousColumn) + 1;

            table.addColumn(idx, newColumn);
        }
        else
        {
            table.addColumn(newColumn);
        }
    }
}