/*
 * Licensed 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 com.facebook.presto.raptor.systemtables;

import com.facebook.presto.spi.Page;
import com.facebook.presto.spi.PageBuilder;
import com.facebook.presto.spi.block.BlockBuilder;
import com.facebook.presto.spi.type.Type;
import com.google.common.collect.ImmutableList;

import java.util.List;

class PageListBuilder
{
    private final PageBuilder pageBuilder;
    private final ImmutableList.Builder<Page> pages = ImmutableList.builder();
    private int channel;

    public PageListBuilder(List<Type> types)
    {
        this.pageBuilder = new PageBuilder(types);
    }

    public List<Page> build()
    {
        if (!pageBuilder.isEmpty()) {
            pages.add(pageBuilder.build());
            pageBuilder.reset();
        }
        return pages.build();
    }

    public void beginRow()
    {
        if (pageBuilder.isFull()) {
            pages.add(pageBuilder.build());
            pageBuilder.reset();
        }
        pageBuilder.declarePosition();
        channel = 0;
    }

    public BlockBuilder nextBlockBuilder()
    {
        int currentChannel = channel;
        channel++;
        return pageBuilder.getBlockBuilder(currentChannel);
    }
}
