/*
 * Copyright (c) 2016 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.restconf.restful.utils;

import com.google.common.base.Preconditions;
import com.google.common.util.concurrent.CheckedFuture;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
import org.opendaylight.controller.md.sal.dom.api.DOMDataReadWriteTransaction;
import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
import org.opendaylight.controller.md.sal.dom.api.DOMTransactionChain;
import org.opendaylight.netconf.sal.restconf.impl.RestconfDocumentedException;
import org.opendaylight.netconf.sal.restconf.impl.RestconfError.ErrorTag;
import org.opendaylight.netconf.sal.restconf.impl.RestconfError.ErrorType;
import org.opendaylight.restconf.RestConnectorProvider;
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.impl.schema.ImmutableNodes;
import org.opendaylight.yangtools.yang.model.api.ListSchemaNode;
import org.opendaylight.yangtools.yang.model.api.Module;
import org.opendaylight.yangtools.yang.model.api.SchemaContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Util class for common methods of transactions
 *
 */
public final class TransactionUtil {

    private final static Logger LOG = LoggerFactory.getLogger(TransactionUtil.class);

    private TransactionUtil() {
        throw new UnsupportedOperationException("Util class");
    }

    /**
     * Merged parents of data
     *
     * @param path
     *            - path of data
     * @param schemaContext
     *            - {@link SchemaContext}
     * @param writeTx
     *            - write transaction
     */
    public static void ensureParentsByMerge(final YangInstanceIdentifier path, final SchemaContext schemaContext,
            final DOMDataWriteTransaction writeTx) {
        final List<PathArgument> normalizedPathWithoutChildArgs = new ArrayList<>();
        boolean hasList = false;
        YangInstanceIdentifier rootNormalizedPath = null;

        final Iterator<PathArgument> it = path.getPathArguments().iterator();
        final Module module = schemaContext.findModuleByNamespaceAndRevision(
                path.getLastPathArgument().getNodeType().getModule().getNamespace(),
                path.getLastPathArgument().getNodeType().getModule().getRevision());

        while (it.hasNext()) {
            final PathArgument pathArgument = it.next();
            if (rootNormalizedPath == null) {
                rootNormalizedPath = YangInstanceIdentifier.create(pathArgument);
            }
            if (it.hasNext()) {
                normalizedPathWithoutChildArgs.add(pathArgument);
                if (module.getDataChildByName(pathArgument.getNodeType()) instanceof ListSchemaNode) {
                    hasList = true;
                }
            }
        }
        if (normalizedPathWithoutChildArgs.isEmpty()) {
            return;
        }
        if (hasList) {
            Preconditions.checkArgument(rootNormalizedPath != null, "Empty path received");
            final NormalizedNode<?, ?> parentStructure = ImmutableNodes.fromInstanceId(schemaContext,
                    YangInstanceIdentifier.create(normalizedPathWithoutChildArgs));
            writeTx.merge(LogicalDatastoreType.CONFIGURATION, rootNormalizedPath, parentStructure);
        }
    }

    /**
     * Check if items already exists at specified {@code path}. Throws {@link RestconfDocumentedException} if
     * data does NOT already exists.
     * @param transactionChain Transaction chain
     * @param rWTransaction Transaction
     * @param store Datastore
     * @param path Path to be checked
     * @param operationType Type of operation (READ, POST, PUT, DELETE...)
     */
    public static void checkItemExists(final DOMTransactionChain transactionChain,
                                       final DOMDataReadWriteTransaction rWTransaction,
                                       final LogicalDatastoreType store, final YangInstanceIdentifier path,
                                       final String operationType) {
        final CheckedFuture<Boolean, ReadFailedException> future = rWTransaction.exists(store, path);
        final FutureDataFactory<Boolean> response = new FutureDataFactory<>();

        FutureCallbackTx.addCallback(future, operationType, response);

        if (!response.result) {
            // close transaction and reset transaction chain
            rWTransaction.cancel();
            RestConnectorProvider.resetTransactionChainForAdapaters(transactionChain);

            // throw error
            final String errMsg = "Operation via Restconf was not executed because data does not exist";
            LOG.trace("{}:{}", errMsg, path);
            throw new RestconfDocumentedException(
                    "Data does not exist", ErrorType.PROTOCOL, ErrorTag.DATA_MISSING, path);
        }
    }

    /**
     * Check if items do NOT already exists at specified {@code path}. Throws {@link RestconfDocumentedException} if
     * data already exists.
     * @param transactionChain Transaction chain
     * @param rWTransaction Transaction
     * @param store Datastore
     * @param path Path to be checked
     * @param operationType Type of operation (READ, POST, PUT, DELETE...)
     */
    public static void checkItemDoesNotExists(final DOMTransactionChain transactionChain,
                                              final DOMDataReadWriteTransaction rWTransaction,
                                              final LogicalDatastoreType store, final YangInstanceIdentifier path,
                                              final String operationType) {
        final CheckedFuture<Boolean, ReadFailedException> future = rWTransaction.exists(store, path);
        final FutureDataFactory<Boolean> response = new FutureDataFactory<>();

        FutureCallbackTx.addCallback(future, operationType, response);

        if (response.result) {
            // close transaction and reset transaction chain
            rWTransaction.cancel();
            RestConnectorProvider.resetTransactionChainForAdapaters(transactionChain);

            // throw error
            final String errMsg = "Operation via Restconf was not executed because data already exists";
            LOG.trace("{}:{}", errMsg, path);
            throw new RestconfDocumentedException(
                    "Data already exists", ErrorType.PROTOCOL, ErrorTag.DATA_EXISTS, path);
        }
    }
}