/*
 * 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.ignite.internal.processors.query.h2.twostep;

import java.util.ArrayList;
import org.apache.ignite.internal.processors.query.h2.opt.H2ScanIndex;
import org.apache.ignite.internal.util.typedef.F;
import org.h2.command.ddl.CreateTableData;
import org.h2.engine.Session;
import org.h2.index.Index;
import org.h2.index.IndexType;
import org.h2.message.DbException;
import org.h2.result.Row;
import org.h2.table.IndexColumn;
import org.h2.table.TableBase;
import org.h2.table.TableType;

/**
 * Table for reduce phase. Created for every splitted map query. Tables are created in H2 through SQL statement.
 * In order to avoid overhead on SQL execution for every query, we create {@link ReduceTableWrapper} instead
 * and set real {@code ReduceTable} through thread-local during query execution. This allow us to have only
 * very limited number of physical tables in H2 for all user requests.
 */
public class ReduceTable extends TableBase {
    /** */
    private ArrayList<Index> idxs;

    /**
     * @param data Data.
     */
    public ReduceTable(CreateTableData data) {
        super(data);
    }

    /**
     * @param idxs Indexes.
     */
    @SuppressWarnings("AssignmentOrReturnOfFieldWithMutableType")
    public void indexes(ArrayList<Index> idxs) {
        assert !F.isEmpty(idxs);

        this.idxs = idxs;
    }

    /**
     * @return Merge index.
     */
    public Reducer getReducer() {
        final Index idx = idxs.get(idxs.size() - 1);

        assert idx instanceof AbstractReduceIndexAdapter : "Reducer index not found.";

        return ((AbstractReduceIndexAdapter)idx).reducer(); // Sorted index must be the last.
    }

    /**
     * @param idx Index.
     * @return Scan index.
     */
    public static H2ScanIndex<AbstractReduceIndexAdapter> createScanIndex(AbstractReduceIndexAdapter idx) {
        return new H2ScanIndex<>(idx);
    }

    /** {@inheritDoc} */
    @Override public boolean lock(Session session, boolean exclusive, boolean force) {
        return false;
    }

    /** {@inheritDoc} */
    @Override public void close(Session ses) {
        // No-op.
    }

    /** {@inheritDoc} */
    @Override public void unlock(Session s) {
        // No-op.
    }

    /** {@inheritDoc} */
    @Override public Index addIndex(Session session, String indexName, int indexId, IndexColumn[] cols,
        IndexType indexType, boolean create, String indexComment) {
        throw DbException.getUnsupportedException("addIndex");
    }

    /** {@inheritDoc} */
    @Override public void removeRow(Session session, Row row) {
        throw DbException.getUnsupportedException("removeRow");
    }

    /** {@inheritDoc} */
    @Override public void truncate(Session session) {
        throw DbException.getUnsupportedException("truncate");
    }

    /** {@inheritDoc} */
    @Override public void addRow(Session session, Row row) {
        throw DbException.getUnsupportedException("addRow");
    }

    /** {@inheritDoc} */
    @Override public void checkSupportAlter() {
        throw DbException.getUnsupportedException("alter");
    }

    /** {@inheritDoc} */
    @Override public TableType getTableType() {
        return TableType.TABLE;
    }

    /** {@inheritDoc} */
    @Override public Index getScanIndex(Session session) {
        return idxs.get(0); // Must be always at 0.
    }

    /** {@inheritDoc} */
    @Override public Index getUniqueIndex() {
        return null; // We don't have a PK.
    }

    /** {@inheritDoc} */
    @SuppressWarnings("AssignmentOrReturnOfFieldWithMutableType")
    @Override public ArrayList<Index> getIndexes() {
        return idxs;
    }

    /** {@inheritDoc} */
    @Override public boolean isLockedExclusively() {
        return false;
    }

    /** {@inheritDoc} */
    @Override public long getMaxDataModificationId() {
        return 0;
    }

    /** {@inheritDoc} */
    @Override public boolean isDeterministic() {
        return true;
    }

    /** {@inheritDoc} */
    @Override public boolean canGetRowCount() {
        return true;
    }

    /** {@inheritDoc} */
    @Override public boolean canDrop() {
        return true;
    }

    /** {@inheritDoc} */
    @Override public long getRowCount(Session ses) {
        return getScanIndex(ses).getRowCount(ses);
    }

    /** {@inheritDoc} */
    @Override public long getRowCountApproximation() {
        return getScanIndex(null).getRowCountApproximation();
    }

    /** {@inheritDoc} */
    @Override public long getDiskSpaceUsed() {
        return 0;
    }

    /** {@inheritDoc} */
    @Override public void checkRename() {
        throw DbException.getUnsupportedException("rename");
    }
}
