/*
 * Copyright (c) 2013, OpenCloudDB/MyCAT and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software;Designed and Developed mainly by many Chinese 
 * opensource volunteers. you can redistribute it and/or modify it under the 
 * terms of the GNU General Public License version 2 only, as published by the
 * Free Software Foundation.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 * 
 * Any questions about this component can be directed to it's project Web address 
 * https://code.google.com/p/opencloudb/.
 *
 */
package com.akiban.sql.parser;

import com.akiban.sql.StandardException;

/**
 * List of IndexColumns. Also notes application of up to one function to
 * a consecutive list of IndexColumns.
 */
public class IndexColumnList extends QueryTreeNodeList<IndexColumn>
{
    private FunctionApplication functionApplication;

    public static enum FunctionType
    {
        Z_ORDER_LAT_LON, FULL_TEXT
        // ADD MORE AS NEEDED
    }

    private static class FunctionApplication
    {
        public FunctionApplication(FunctionType functionType,
                                   int firstArgumentPosition,
                                   int nArguments)
        {
            this.functionType = functionType;
            this.firstArgumentPosition = firstArgumentPosition;
            this.lastArgumentPosition = firstArgumentPosition + nArguments - 1;
            this.nArguments = nArguments;
        }

        public final FunctionType functionType;
        public final int firstArgumentPosition;
        public final int lastArgumentPosition;
        public final int nArguments;
    }

    public void applyFunction(Object functionType,
                              int firstArgumentPosition,
                              int nArguments) throws StandardException
    {
        if (functionApplication != null) {
            throw new StandardException("Cannot use multiple functions in one index definition");
        }
        functionApplication = new FunctionApplication((FunctionType) functionType,
                                                      firstArgumentPosition,
                                                      nArguments);
    }

    public int firstFunctionArg()
    {
        return
            functionApplication == null
            ? Integer.MAX_VALUE
            : functionApplication.firstArgumentPosition;
    }

    public int lastFunctionArg()
    {
        return
            functionApplication == null
            ? Integer.MIN_VALUE
            : functionApplication.lastArgumentPosition;
    }

    public FunctionType functionType()
    {
        return functionApplication == null ? null : functionApplication.functionType;
    }

    @Override
    public void copyFrom(QueryTreeNode node) throws StandardException
    {
        super.copyFrom(node);
        IndexColumnList that = (IndexColumnList) node;
        this.functionApplication = that.functionApplication;
    }

    @Override
    public String toString()
    {
        return
            functionApplication != null
            ? String.format("\nmethodName: %s\nfirstArg: %s\nlastArg: %s\n",
                            functionApplication.functionType, functionApplication.firstArgumentPosition, functionApplication.lastArgumentPosition)
            : super.toString();
    }
}