/*
 * Copyright (c) 2015 Cisco Systems, Inc. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */
package org.opendaylight.yangtools.yang.data.api.schema.tree.spi;

import com.google.common.base.MoreObjects.ToStringHelper;
import com.google.common.base.Optional;
import com.google.common.collect.Collections2;
import java.util.Map;
import org.opendaylight.yangtools.util.MapAdaptor;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;

/**
 * Lazily-materialized container node. Any new/modified children are tracked in a map. This map is consulted before
 * instantiating a child node from data node. Resulting node is not cached.
 */
final class LazyContainerNode extends AbstractModifiedContainerNode {
    LazyContainerNode(final NormalizedNode<?, ?> data, final Version version, final Version subtreeVersion) {
        this(data, version, MapAdaptor.getDefaultInstance().initialSnapshot(1), subtreeVersion);
    }

    LazyContainerNode(final NormalizedNode<?, ?> data, final Version version, final Map<PathArgument, TreeNode> children,
            final Version subtreeVersion) {
        super(data, version, children, subtreeVersion);
    }

    @Override
    public MutableTreeNode mutable() {
        final Map<PathArgument, TreeNode> snapshot = snapshotChildren();
        if (snapshot.size() == castData().getValue().size()) {
            return new MaterializedMutableContainerNode(this, snapshot);
        }

        return new LazyMutableContainerNode(this, snapshot);
    }

    @Override
    public Optional<TreeNode> getChild(final PathArgument childId) {
        final TreeNode modified = getModifiedChild(childId);
        return modified == null ? getChildFromData(childId) : Optional.of(modified);
    }

    @Override
    protected ToStringHelper addToStringAttributes(final ToStringHelper helper) {
        // Modified children add added by superclass. Here we filter the other children.
        return super.addToStringAttributes(helper).add("untouched", Collections2.filter(castData().getValue(),
            input -> getModifiedChild(input.getIdentifier()) == null));
    }
}