/*
 * 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.impl.schema.tree;

import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import java.util.ArrayDeque;
import java.util.Deque;
import javax.annotation.Nonnull;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodeContainer;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodes;

final class InMemoryDataTreeSnapshotCursor extends AbstractCursor<InMemoryDataTreeSnapshot> {
    private final Deque<NormalizedNodeContainer<?, ?, ?>> stack = new ArrayDeque<>();

    InMemoryDataTreeSnapshotCursor(final InMemoryDataTreeSnapshot parent, final YangInstanceIdentifier rootPath, final NormalizedNodeContainer<?, ?, ?> normalizedNode) {
        super(parent, rootPath);
        stack.push(normalizedNode);
    }

    @Override
    public void enter(@Nonnull final PathArgument child) {
        final Optional<NormalizedNode<?, ?>> maybeChildNode = NormalizedNodes.getDirectChild(stack.peek(), child);
        Preconditions.checkArgument(maybeChildNode.isPresent(), "Child %s not found", child);

        final NormalizedNode<?, ?> childNode = maybeChildNode.get();
        Preconditions.checkArgument(childNode instanceof NormalizedNodeContainer, "Child %s is not a container", child);
        stack.push((NormalizedNodeContainer<?, ?, ?>) childNode);
    }

    @Override
    public void enter(@Nonnull final Iterable<PathArgument> path) {
        final Optional<NormalizedNode<?, ?>> maybeChildNode = NormalizedNodes.findNode(stack.peek(), path);
        Preconditions.checkArgument(maybeChildNode.isPresent(), "Child %s not found", path);

        final NormalizedNode<?, ?> childNode = maybeChildNode.get();
        Preconditions.checkArgument(childNode instanceof NormalizedNodeContainer, "Child %s is not a container", path);

        int depth = 0;
        for (PathArgument arg : path) {
            try {
                enter(arg);
            } catch (Exception e) {
                for (int i = 0; i < depth; ++i) {
                    stack.pop();
                }
                throw new IllegalArgumentException(e);
            }

            ++depth;
        }
    }

    @Override
    public void exit(final int depth) {
        Preconditions.checkArgument(depth >= 0);
        Preconditions.checkState(depth < stack.size());

        for (int i = 0; i < depth; ++i) {
            stack.pop();
        }
    }

    @Override
    public Optional<NormalizedNode<?, ?>> readNode(@Nonnull final PathArgument child) {
        return NormalizedNodes.findNode(stack.peek(), child);
    }
}