/**
 * Copyright (C) 2009-2013 FoundationDB, LLC
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.foundationdb.ais.model;

import java.util.Collections;
import java.util.List;

public class HKeyColumn
{
    @Override
    public String toString()
    {
        StringBuilder buffer = new StringBuilder();
        buffer.append(column().getTable().getName().getTableName());
        buffer.append('.');
        buffer.append(column().getName());
        return buffer.toString();
    }

    public HKeySegment segment()
    {
        return segment;
    }

    public Column column()
    {
        return column;
    }

    public List<Column> equivalentColumns()
    {
        return equivalentColumns;
    }

    public int positionInHKey()
    {
        return positionInHKey;
    }

    public HKeyColumn(HKeySegment segment, Column column)
    {
        this.segment = segment;
        this.column = column;
        this.positionInHKey = segment.positionInHKey() + segment.columns().size() + 1;
        this.equivalentColumns = Collections.unmodifiableList(column.getTable().matchingColumns(column));
    }

    // For use by this class
    
    private void findDependentTables(Column column, Table table, List<Table> dependentTables)
    {
        boolean dependent = false;
        for (HKeySegment segment : table.hKey().segments()) {
            for (HKeyColumn hKeyColumn : segment.columns()) {
                dependent = dependent || hKeyColumn.column() == column;
            }
        }
        if (dependent) {
            dependentTables.add(table);
        }
        for (Join join : table.getChildJoins()) {
            findDependentTables(column, join.getChild(), dependentTables);
        }
    }

    // State

    private final HKeySegment segment;
    private final Column column;
    private final int positionInHKey;
    // If column is a group table column, then we need to know all columns in the group table that are constrained
    // to have matching values, e.g. customer$cid and order$cid. For a user table, equivalentColumns contains just
    // column.
    private final List<Column> equivalentColumns;
}