/**
 * 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.qp.operator;

import com.foundationdb.qp.row.Row;
import com.foundationdb.qp.rowtype.RowType;
import com.foundationdb.server.explain.CompoundExplainer;
import com.foundationdb.server.explain.ExplainContext;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;

public class TimeOperator extends Operator
{
    // Object interface

    @Override
    public String toString()
    {
        return getClass().getSimpleName();
    }

    // Operator interface

    @Override
    protected Cursor cursor(QueryContext context, QueryBindingsCursor bindingsCursor)
    {
        return new Execution(context, bindingsCursor);
    }

    @Override
    public void findDerivedTypes(Set<RowType> derivedTypes)
    {
        inputOperator.findDerivedTypes(derivedTypes);
    }

    @Override
    public List<Operator> getInputOperators()
    {
        List<Operator> result = new ArrayList<>(1);
        result.add(inputOperator);
        return result;
    }

    @Override
    public String describePlan()
    {
        return describePlan(inputOperator);
    }

    // TimeOperator interface

    public long elapsedNsec()
    {
        return elapsedNsec;
    }

    public TimeOperator(Operator inputOperator)
    {
        this.inputOperator = inputOperator;
    }

    // Object state

    private final Operator inputOperator;
    private long elapsedNsec = 0;

    @Override
    public CompoundExplainer getExplainer(ExplainContext context) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    // Inner classes

    private class Execution extends ChainedCursor
    {
        // Cursor interface

        @Override
        public void open()
        {
            super.open();
            long start = System.nanoTime();
            input.open();
            long stop = System.nanoTime();
            elapsedNsec += stop - start;
        }

        @Override
        public Row next()
        {
            long start = System.nanoTime();
            Row next = input.next();
            long stop = System.nanoTime();
            elapsedNsec += stop - start;
            return next;
        }

        @Override
        public void close()
        {
            try {
                long start = System.nanoTime();
                input.close();
                long stop = System.nanoTime();
                elapsedNsec += stop - start;
            } finally {
                super.close();
            }
        }

        // Execution interface

        Execution(QueryContext context, QueryBindingsCursor bindingsCursor)
        {
            super(context, inputOperator.cursor(context, bindingsCursor));
        }
    }
}