/*
 * Copyright (c) 2014 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.controller.md.sal.dom.store.impl.tree;

import java.util.Set;

import org.opendaylight.yangtools.concepts.Identifiable;
import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier;
import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier.AugmentationIdentifier;
import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier.NodeIdentifierWithPredicates;
import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier.PathArgument;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodeContainer;

import com.google.common.base.Function;
import com.google.common.base.Strings;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableList;
import com.google.common.primitives.UnsignedLong;

public final class StoreUtils {
    private static final int STRINGTREE_INDENT = 4;

    private final static Function<Identifiable<Object>, Object> EXTRACT_IDENTIFIER = new Function<Identifiable<Object>, Object>() {
        @Override
        public Object apply(final Identifiable<Object> input) {
            return input.getIdentifier();
        }
    };

    private StoreUtils() {
        throw new UnsupportedOperationException("Utility class should not be instantiated");
    }

    /*
     * Suppressing warnings here allows us to fool the compiler enough
     * such that we can reuse a single function for all applicable types
     * and present it in a type-safe manner to our users.
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
    public static <V> Function<Identifiable<V>, V> identifierExtractor() {
        return (Function) EXTRACT_IDENTIFIER;
    }

    public static final UnsignedLong increase(final UnsignedLong original) {
        return original.plus(UnsignedLong.ONE);
    }

    public static final InstanceIdentifier append(final InstanceIdentifier parent, final PathArgument arg) {
        return new InstanceIdentifier(ImmutableList.<PathArgument> builder().addAll(parent.getPath()).add(arg).build());
    }

    public static <V> Set<V> toIdentifierSet(final Iterable<? extends Identifiable<V>> children) {
        return FluentIterable.from(children).transform(StoreUtils.<V> identifierExtractor()).toSet();
    }

    public static String toStringTree(final NormalizedNode<?, ?> node) {
        StringBuilder builder = new StringBuilder();
        toStringTree(builder, node, 0);
        return builder.toString();
    }

    private static void toStringTree(final StringBuilder builder, final NormalizedNode<?, ?> node, final int offset) {
        final String prefix = Strings.repeat(" ", offset);

        builder.append(prefix).append(toStringTree(node.getIdentifier()));
        if (node instanceof NormalizedNodeContainer<?, ?, ?>) {
            final NormalizedNodeContainer<?, ?, ?> container = (NormalizedNodeContainer<?, ?, ?>) node;

            builder.append(" {\n");
            for (NormalizedNode<?, ?> child : container.getValue()) {
                toStringTree(builder, child, offset + STRINGTREE_INDENT);
            }

            builder.append(prefix).append('}');
        } else {
            builder.append(' ').append(node.getValue());
        }
        builder.append('\n');
    }

    private static String toStringTree(final PathArgument identifier) {
        if (identifier instanceof NodeIdentifierWithPredicates) {
            StringBuilder builder = new StringBuilder();
            builder.append(identifier.getNodeType().getLocalName());
            builder.append(((NodeIdentifierWithPredicates) identifier).getKeyValues().values());
            return builder.toString();
        } else if (identifier instanceof AugmentationIdentifier) {
            return "augmentation";
        }
        return identifier.getNodeType().getLocalName();
    }
}