/*
 * 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.opt;

import java.util.List;
import org.apache.ignite.internal.cache.query.index.Index;
import org.apache.ignite.internal.processors.cache.CacheObject;
import org.apache.ignite.internal.processors.cache.GridCacheContext;
import org.apache.ignite.internal.processors.query.QueryUtils;
import org.apache.ignite.internal.processors.query.h2.H2Utils;
import org.apache.ignite.internal.processors.query.h2.opt.join.CollocationModel;
import org.apache.ignite.internal.processors.query.h2.opt.join.CollocationModelMultiplier;
import org.apache.ignite.spi.indexing.IndexingQueryCacheFilter;
import org.h2.engine.Session;
import org.h2.index.IndexType;
import org.h2.message.DbException;
import org.h2.result.Row;
import org.h2.result.SearchRow;
import org.h2.table.IndexColumn;
import org.h2.table.TableFilter;
import org.h2.value.Value;
import org.jetbrains.annotations.NotNull;

/**
 * Index base.
 */
public abstract class GridH2IndexBase extends H2IndexCostedBase {
    /**
     * Constructor.
     *
     * @param tbl Table.
     * @param name Index name.
     * @param cols Indexed columns.
     * @param type Index type.
     */
    protected GridH2IndexBase(GridH2Table tbl, String name, IndexColumn[] cols, IndexType type) {
        super(tbl, name, cols, type);
    }

    /** {@inheritDoc} */
    @Override public final void close(Session ses) {
        // No-op. Actual index destruction must happen in method destroy.
    }

    /**
     * Attempts to destroys index and release all the resources.
     * We use this method instead of {@link #close(Session)} because that method
     * is used by H2 internally.
     */
    public void destroy() {
        // No-op.
    }

    /**
     * @param qctx Query context.
     * @return Index segment ID for current query context.
     */
    protected int segment(QueryContext qctx) {
        if (segmentsCount() == 1)
            return 0;

        if (qctx == null)
            throw new IllegalStateException("GridH2QueryContext is not initialized.");

        return qctx.segment();
    }

    /**
     * Puts row.
     *
     * @param row Row.
     * @return Existing row or {@code null}.
     */
    public abstract H2CacheRow put(H2CacheRow row);

    /**
     * Puts row.
     *
     * @param row Row.
     * @return {@code True} if existing row row has been replaced.
     */
    public abstract boolean putx(H2CacheRow row);

    /**
     * Removes row from index.
     *
     * @param row Row.
     * @return {@code True} if row has been removed.
     */
    public abstract boolean removex(SearchRow row);

    /**
     * @param ses Session.
     * @param filters All joined table filters.
     * @param filter Current filter.
     * @return Multiplier.
     */
    public final int getDistributedMultiplier(Session ses, TableFilter[] filters, int filter) {
        CollocationModelMultiplier mul = CollocationModel.distributedMultiplier(ses, filters, filter);

        return mul.multiplier();
    }

    /** {@inheritDoc} */
    @Override public GridH2Table getTable() {
        return (GridH2Table)super.getTable();
    }

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

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

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

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

    /** {@inheritDoc} */
    @Override public void remove(Session ses) {
        // No-op: destroyed from owning table.
    }

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

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

    /**
     * @return Index segments count.
     */
    public abstract int segmentsCount();

    /**
     * @param partition Partition idx.
     * @return Segment ID for given key
     */
    public int segmentForPartition(int partition) {
        return segmentsCount() == 1 ? 0 : (partition % segmentsCount());
    }

    /**
     * @param row Table row.
     * @return Segment ID for given row.
     */
    @SuppressWarnings("IfMayBeConditional")
    protected int segmentForRow(GridCacheContext ctx, SearchRow row) {
        assert row != null;

        if (segmentsCount() == 1 || ctx == null)
            return 0;

        CacheObject key;

        final Value keyColVal = row.getValue(QueryUtils.KEY_COL);

        assert keyColVal != null;

        final Object o = keyColVal.getObject();

        if (o instanceof CacheObject)
            key = (CacheObject)o;
        else
            key = ctx.toCacheKeyObject(o);

        return segmentForPartition(ctx.affinity().partition(key));
    }

    /**
     * Re-assign column ids after removal of column(s).
     */
    public void refreshColumnIds() {
        assert columnIds.length == columns.length;

        for (int pos = 0; pos < columnIds.length; ++pos)
            columnIds[pos] = columns[pos].getColumnId();
    }

    /**
     * @return Row descriptor.
     */
    protected GridH2RowDescriptor rowDescriptor() {
        return ((GridH2Table)table).rowDescriptor();
    }

    /**
     * @return Query context registry.
     */
    protected QueryContextRegistry queryContextRegistry() {
        return ((GridH2Table)table).tableDescriptor().indexing().queryContextRegistry();
    }


    /** {@inheritDoc} */
    @Override public long getRowCountApproximation() {
        return ((GridH2Table)table).getRowCountApproximation();
    }

    /**
     * @param partsFilter Partitions filter.
     * @return Total row count in the current index for filtered partitions.
     */
    public abstract long totalRowCount(IndexingQueryCacheFilter partsFilter);

    /**
     * @param tbl Table.
     * @param colsList Columns list.
     * @return Index column array.
     */
    @NotNull public static IndexColumn[] columnsArray(GridH2Table tbl, List<IndexColumn> colsList) {
        IndexColumn[] cols = colsList.toArray(H2Utils.EMPTY_COLUMNS);

        IndexColumn.mapColumns(cols, tbl);

        return cols;
    }

    /**
     * Finds an instance of an interface implemented by this object,
     * or returns null if this object does not support that interface.
     */
    public <T extends Index> T unwrap(Class<T> clazz) {
        if (clazz == null)
            return null;

        if (clazz.isAssignableFrom(getClass()))
            return clazz.cast(this);

        return null;
    }
}
