/*
 * 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.parser.stmt.rfc6020;

import com.google.common.base.Preconditions;
import java.util.Collection;
import java.util.regex.Pattern;
import javax.annotation.Nonnull;
import org.opendaylight.yangtools.yang.model.api.Rfc6020Mapping;
import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
import org.opendaylight.yangtools.yang.model.api.stmt.AugmentStatement;
import org.opendaylight.yangtools.yang.model.api.stmt.DataDefinitionStatement;
import org.opendaylight.yangtools.yang.model.api.stmt.SchemaNodeIdentifier;
import org.opendaylight.yangtools.yang.parser.spi.SubstatementValidator;
import org.opendaylight.yangtools.yang.parser.spi.meta.AbstractDeclaredStatement;
import org.opendaylight.yangtools.yang.parser.spi.meta.AbstractStatementSupport;
import org.opendaylight.yangtools.yang.parser.spi.meta.InferenceException;
import org.opendaylight.yangtools.yang.parser.spi.meta.ModelActionBuilder;
import org.opendaylight.yangtools.yang.parser.spi.meta.ModelActionBuilder.Prerequisite;
import org.opendaylight.yangtools.yang.parser.spi.meta.ModelProcessingPhase;
import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext;
import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext.Mutable;
import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContextUtils;
import org.opendaylight.yangtools.yang.parser.spi.source.AugmentToChoiceNamespace;
import org.opendaylight.yangtools.yang.parser.spi.source.SourceException;
import org.opendaylight.yangtools.yang.parser.spi.source.StmtOrderingNamespace;
import org.opendaylight.yangtools.yang.parser.stmt.reactor.StatementContextBase;
import org.opendaylight.yangtools.yang.parser.stmt.rfc6020.effective.AugmentEffectiveStatementImpl;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class AugmentStatementImpl extends AbstractDeclaredStatement<SchemaNodeIdentifier> implements AugmentStatement {
    private static final Logger LOG = LoggerFactory.getLogger(AugmentStatementImpl.class);
    private static final Pattern PATH_REL_PATTERN1 = Pattern.compile("\\.\\.?\\s*/(.+)");
    private static final Pattern PATH_REL_PATTERN2 = Pattern.compile("//.*");
    private static final SubstatementValidator SUBSTATEMENT_VALIDATOR = SubstatementValidator
            .builder(Rfc6020Mapping.AUGMENT)
            .addAny(Rfc6020Mapping.ANYXML)
            .addAny(Rfc6020Mapping.CASE)
            .addAny(Rfc6020Mapping.CHOICE)
            .addAny(Rfc6020Mapping.CONTAINER)
            .addOptional(Rfc6020Mapping.DESCRIPTION)
            .addAny(Rfc6020Mapping.IF_FEATURE)
            .addAny(Rfc6020Mapping.LEAF)
            .addAny(Rfc6020Mapping.LEAF_LIST)
            .addAny(Rfc6020Mapping.LIST)
            .addOptional(Rfc6020Mapping.REFERENCE)
            .addOptional(Rfc6020Mapping.STATUS)
            .addAny(Rfc6020Mapping.USES)
            .addOptional(Rfc6020Mapping.WHEN)
            .build();

    protected AugmentStatementImpl(final StmtContext<SchemaNodeIdentifier, AugmentStatement, ?> context) {
        super(context);
    }

    public static class Definition extends
            AbstractStatementSupport<SchemaNodeIdentifier, AugmentStatement, EffectiveStatement<SchemaNodeIdentifier, AugmentStatement>> {

        public Definition() {
            super(Rfc6020Mapping.AUGMENT);
        }

        @Override
        public SchemaNodeIdentifier parseArgumentValue(final StmtContext<?, ?, ?> ctx, final String value) {
            Preconditions.checkArgument(!PATH_REL_PATTERN1.matcher(value).matches()
                && !PATH_REL_PATTERN2.matcher(value).matches(),
                "An argument for augment can be only absolute path; or descendant if used in uses");

            return Utils.nodeIdentifierFromPath(ctx, value);
        }

        @Override
        public AugmentStatement createDeclared(
                final StmtContext<SchemaNodeIdentifier, AugmentStatement, ?> ctx) {
            return new AugmentStatementImpl(ctx);
        }

        @Override
        public EffectiveStatement<SchemaNodeIdentifier, AugmentStatement> createEffective(
                final StmtContext<SchemaNodeIdentifier, AugmentStatement, EffectiveStatement<SchemaNodeIdentifier, AugmentStatement>> ctx) {
            return new AugmentEffectiveStatementImpl(ctx);
        }

        @Override
        public void onFullDefinitionDeclared(
                final StmtContext.Mutable<SchemaNodeIdentifier, AugmentStatement, EffectiveStatement<SchemaNodeIdentifier, AugmentStatement>> augmentNode) {
            if (!StmtContextUtils.areFeaturesSupported(augmentNode)) {
                return;
            }

            SUBSTATEMENT_VALIDATOR.validate(augmentNode);

            if (StmtContextUtils.isInExtensionBody(augmentNode)) {
                return;
            }

            final ModelActionBuilder augmentAction = augmentNode.newInferenceAction(
                ModelProcessingPhase.EFFECTIVE_MODEL);
            final ModelActionBuilder.Prerequisite<StmtContext<SchemaNodeIdentifier, AugmentStatement, EffectiveStatement<SchemaNodeIdentifier, AugmentStatement>>> sourceCtxPrereq =
                    augmentAction.requiresCtx(augmentNode, ModelProcessingPhase.EFFECTIVE_MODEL);
            final Prerequisite<Mutable<?, ?, EffectiveStatement<?, ?>>> target =
                    augmentAction.mutatesEffectiveCtx(getSearchRoot(augmentNode), SchemaNodeIdentifierBuildNamespace.class, augmentNode.getStatementArgument());
            augmentAction.apply(new ModelActionBuilder.InferenceAction() {

                @Override
                public void apply() {
                    final StatementContextBase<?, ?, ?> augmentTargetCtx = (StatementContextBase<?, ?, ?>) target.get();
                    if (!AugmentUtils.isSupportedAugmentTarget(augmentTargetCtx)
                            || StmtContextUtils.isInExtensionBody(augmentTargetCtx)) {
                        augmentNode.setIsSupportedToBuildEffective(false);
                        return;
                    }
                    /**
                     * Marks case short hand in augment
                     */
                    if (augmentTargetCtx.getPublicDefinition() == Rfc6020Mapping.CHOICE) {
                        augmentNode.addToNs(AugmentToChoiceNamespace.class, augmentNode, true);
                    }

                    // FIXME: this is a workaround for models which augment a node which is added via an extension
                    //        which we do not handle. This needs to be reworked in terms of unknown schema nodes.
                    final StatementContextBase<?, ?, ?> augmentSourceCtx = (StatementContextBase<?, ?, ?>) augmentNode;
                    try {
                        AugmentUtils.copyFromSourceToTarget(augmentSourceCtx, augmentTargetCtx);
                        augmentTargetCtx.addEffectiveSubstatement(augmentSourceCtx);
                        updateAugmentOrder(augmentSourceCtx);
                    } catch (final SourceException e) {
                        LOG.debug("Failed to add augmentation {} defined at {}",
                            augmentTargetCtx.getStatementSourceReference(),
                                augmentSourceCtx.getStatementSourceReference(), e);
                    }
                }

                private void updateAugmentOrder(final StatementContextBase<?, ?, ?> augmentSourceCtx) {
                    Integer currentOrder = augmentSourceCtx.getFromNamespace(StmtOrderingNamespace.class,
                        Rfc6020Mapping.AUGMENT);
                    if (currentOrder == null) {
                        currentOrder = 1;
                    } else {
                        currentOrder++;
                    }

                    augmentSourceCtx.setOrder(currentOrder);
                    augmentSourceCtx.addToNs(StmtOrderingNamespace.class, Rfc6020Mapping.AUGMENT, currentOrder);
                }

                @Override
                public void prerequisiteFailed(final Collection<? extends ModelActionBuilder.Prerequisite<?>> failed) {
                    /*
                     * Do not fail, if it is an uses-augment to an unknown node.
                     */
                    if (Rfc6020Mapping.USES == augmentNode.getParentContext().getPublicDefinition()) {
                        final StatementContextBase<?, ?, ?> targetNode = Utils.findNode(getSearchRoot(augmentNode),
                                augmentNode.getStatementArgument());
                        if (Utils.isUnknownNode(targetNode)) {
                            augmentNode.setIsSupportedToBuildEffective(false);
                            LOG.warn(
                                    "Uses-augment to unknown node {}. Augmentation has not been performed. At line: {}",
                                    augmentNode.getStatementArgument(), augmentNode.getStatementSourceReference());
                            return;
                        }
                    }

                    throw new InferenceException(augmentNode.getStatementSourceReference(),
                            "Augment target '%s' not found", augmentNode.getStatementArgument());
                }
            });
        }

        private static Mutable<?, ?, ?> getSearchRoot(final Mutable<?, ?, ?> augmentContext) {
            final Mutable<?, ?, ?> parent = augmentContext.getParentContext();
            // Augment is in uses - we need to augment instantiated nodes in parent.
            if (Rfc6020Mapping.USES == parent.getPublicDefinition()) {
                return parent.getParentContext();
            }
            return parent;
        }
    }

    @Nonnull
    @Override
    public SchemaNodeIdentifier getTargetNode() {
        return argument();
    }

    @Override
    public Collection<? extends DataDefinitionStatement> getDataDefinitions() {
        return allDeclared(DataDefinitionStatement.class);
    }
}