/*
 * 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.
 */
package org.apache.cassandra.cql3;

import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.config.ColumnDefinition;

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

public class VariableSpecifications
{
    private final List<ColumnIdentifier> variableNames;
    private final ColumnSpecification[] specs;
    private final ColumnDefinition[] targetColumns;

    public VariableSpecifications(List<ColumnIdentifier> variableNames)
    {
        this.variableNames = variableNames;
        this.specs = new ColumnSpecification[variableNames.size()];
        this.targetColumns = new ColumnDefinition[variableNames.size()];
    }

    
Returns an empty instance of VariableSpecifications.
Returns:
an empty instance of VariableSpecifications/**
     * Returns an empty instance of <code>VariableSpecifications</code>.
     * @return an empty instance of <code>VariableSpecifications</code>
     */
    public static VariableSpecifications empty()
    {
        return new VariableSpecifications(Collections.<ColumnIdentifier> emptyList());
    }

    public int size()
    {
        return variableNames.size();
    }

    public List<ColumnSpecification> getSpecifications()
    {
        return Arrays.asList(specs);
    }

    
Returns an array with the same length as the number of partition key columns for the table corresponding
to cfm.  Each short in the array represents the bind index of the marker that holds the value for that
partition key column.  If there are no bind markers for any of the partition key columns, null is returned.
Callers of this method should ensure that all statements operate on the same table.
/**
     * Returns an array with the same length as the number of partition key columns for the table corresponding
     * to cfm.  Each short in the array represents the bind index of the marker that holds the value for that
     * partition key column.  If there are no bind markers for any of the partition key columns, null is returned.
     *
     * Callers of this method should ensure that all statements operate on the same table.
     */
    public short[] getPartitionKeyBindIndexes(CFMetaData cfm)
    {
        short[] partitionKeyPositions = new short[cfm.partitionKeyColumns().size()];
        boolean[] set = new boolean[partitionKeyPositions.length];
        for (int i = 0; i < targetColumns.length; i++)
        {
            ColumnDefinition targetColumn = targetColumns[i];
            if (targetColumn != null && targetColumn.isPartitionKey())
            {
                assert targetColumn.ksName.equals(cfm.ksName) && targetColumn.cfName.equals(cfm.cfName);
                partitionKeyPositions[targetColumn.position()] = (short) i;
                set[targetColumn.position()] = true;
            }
        }

        for (boolean b : set)
            if (!b)
                return null;

        return partitionKeyPositions;
    }

    public void add(int bindIndex, ColumnSpecification spec)
    {
        if (spec instanceof ColumnDefinition)
            targetColumns[bindIndex] = (ColumnDefinition) spec;

        ColumnIdentifier bindMarkerName = variableNames.get(bindIndex);
        // Use the user name, if there is one
        if (bindMarkerName != null)
            spec = new ColumnSpecification(spec.ksName, spec.cfName, bindMarkerName, spec.type);
        specs[bindIndex] = spec;
    }

    @Override
    public String toString()
    {
        return Arrays.toString(specs);
    }
}