/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.atlas.catalog;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import org.apache.atlas.AtlasErrorCode;
import org.apache.atlas.AtlasException;
import org.apache.atlas.catalog.definition.ResourceDefinition;
import org.apache.atlas.catalog.exception.CatalogRuntimeException;
import org.apache.atlas.catalog.exception.ResourceAlreadyExistsException;
import org.apache.atlas.catalog.exception.ResourceNotFoundException;
import org.apache.atlas.exception.AtlasBaseException;
import org.apache.atlas.model.typedef.AtlasClassificationDef;
import org.apache.atlas.model.typedef.AtlasEntityDef;
import org.apache.atlas.model.typedef.AtlasEnumDef;
import org.apache.atlas.model.typedef.AtlasStructDef;
import org.apache.atlas.model.typedef.AtlasTypesDef;
import org.apache.atlas.repository.converters.TypeConverterUtil;
import org.apache.atlas.services.MetadataService;
import org.apache.atlas.store.AtlasTypeDefStore;
import org.apache.atlas.typesystem.ITypedReferenceableInstance;
import org.apache.atlas.typesystem.Referenceable;
import org.apache.atlas.typesystem.Struct;
import org.apache.atlas.typesystem.exception.EntityExistsException;
import org.apache.atlas.typesystem.exception.EntityNotFoundException;
import org.apache.atlas.typesystem.exception.TraitNotFoundException;
import org.apache.atlas.typesystem.types.AttributeDefinition;
import org.apache.atlas.typesystem.types.ClassType;
import org.apache.atlas.typesystem.types.HierarchicalType;
import org.apache.atlas.typesystem.types.TraitType;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;

/**
 * Default implementation.
 */
public class DefaultTypeSystem implements AtlasTypeSystem {
    private final MetadataService metadataService;

    private final AtlasTypeDefStore typeDefStore;

    /**
     * Constructor.
     *
     * @param metadataService  atlas metadata service
     */
    public DefaultTypeSystem(MetadataService metadataService, AtlasTypeDefStore typeDefStore) throws AtlasBaseException {
        this.metadataService = metadataService;
        this.typeDefStore = typeDefStore;
    }

    @Override
    public String createEntity(ResourceDefinition definition, Request request) throws ResourceAlreadyExistsException {
        String typeName = definition.getTypeName();
        try {
            createClassType(definition, typeName, typeName + " Definition");
        } catch (ResourceAlreadyExistsException e) {
            // ok if type already exists
        }
        try {
            Referenceable entity = new Referenceable(typeName, request.getQueryProperties());
            //add Taxonomy Namespace
            entity.set(TaxonomyResourceProvider.NAMESPACE_ATTRIBUTE_NAME, TaxonomyResourceProvider.TAXONOMY_NS);

            ITypedReferenceableInstance typedInstance = metadataService.getTypedReferenceableInstance(entity);
            ITypedReferenceableInstance[] entitiesToCreate = Collections.singletonList(typedInstance).toArray(new ITypedReferenceableInstance[1]);
            final List<String> entities = metadataService.createEntities(entitiesToCreate).getCreatedEntities();
            return entities != null && entities.size() > 0 ? entities.get(0) : null;
        } catch (EntityExistsException e) {
            throw new ResourceAlreadyExistsException(
                    "Attempted to create an entity which already exists: " + request.getQueryProperties());
        } catch (AtlasException e) {
            throw new CatalogRuntimeException("An expected exception occurred creating an entity: " + e, e);
        }
    }

    @Override
    public void deleteEntity(ResourceDefinition definition, Request request) throws ResourceNotFoundException {
        String typeName = definition.getTypeName();
        String cleanIdPropName = definition.getIdPropertyName();
        String idValue = request.getProperty(cleanIdPropName);
        try {
            // transaction handled by atlas repository
            metadataService.deleteEntityByUniqueAttribute(typeName, cleanIdPropName, idValue);
        } catch (EntityNotFoundException e) {
            throw new ResourceNotFoundException(String.format("The specified entity doesn't exist: type=%s, %s=%s",
                    typeName, cleanIdPropName, idValue));
        } catch (AtlasException e) {
            throw new CatalogRuntimeException(String.format(
                    "An unexpected error occurred while attempting to delete entity: type=%s, %s=%s : %s",
                    typeName, cleanIdPropName, idValue, e), e);
        }
    }

    @Override
    public void createClassType(ResourceDefinition resourceDefinition, String name, String description)
            throws ResourceAlreadyExistsException {

        createType(resourceDefinition.getPropertyDefinitions(), ClassType.class, name, description, false);
    }

    @Override
    public void createTraitType(ResourceDefinition resourceDefinition, String name, String description)
            throws ResourceAlreadyExistsException {

        createType(resourceDefinition.getPropertyDefinitions(), TraitType.class, name, description, true);
    }

    @Override
    public void createTraitInstance(String guid, String typeName, Map<String, Object> properties)
            throws ResourceAlreadyExistsException {

        try {
            // not using the constructor with properties argument because it is marked 'InterfaceAudience.Private'
            Struct struct = new Struct(typeName);
            for (Map.Entry<String, Object> propEntry : properties.entrySet()) {
                struct.set(propEntry.getKey(), propEntry.getValue());
            }

            //add Taxonomy Namespace
            struct.set(TaxonomyResourceProvider.NAMESPACE_ATTRIBUTE_NAME, TaxonomyResourceProvider.TAXONOMY_NS);
            metadataService.addTrait(guid, metadataService.createTraitInstance(struct));
        } catch (IllegalArgumentException e) {
            //todo: unfortunately, IllegalArgumentException can be thrown for other reasons
            if (e.getMessage().contains("is already defined for entity")) {
                throw new ResourceAlreadyExistsException(
                        String.format("Tag '%s' already associated with the entity", typeName));
            } else {
                throw e;
            }
        } catch (AtlasException e) {
            throw new CatalogRuntimeException(String.format(
                    "Unable to create trait instance '%s' in type system: %s", typeName, e), e);
        }
    }

    @Override
    public void deleteTag(String guid, String traitName) throws ResourceNotFoundException {
        try {
            metadataService.deleteTrait(guid, traitName);
        } catch (TraitNotFoundException e) {
            throw new ResourceNotFoundException(String.format(
                    "The trait '%s' doesn't exist for entity '%s'", traitName, guid));
        } catch (AtlasException e) {
            throw new CatalogRuntimeException(String.format(
                    "Unable to delete tag '%s' from entity '%s'", traitName, guid), e);
        }
    }

    private <T extends HierarchicalType> void createType(Collection<AttributeDefinition> attributes,
                                                         Class<T> type,
                                                         String name,
                                                         String description,
                                                         boolean isTrait)
        throws ResourceAlreadyExistsException {

        try {
            List<AtlasStructDef.AtlasAttributeDef> attrDefs  = new ArrayList<>();
            for (AttributeDefinition attrDefinition : attributes) {
                attrDefs.add(TypeConverterUtil.toAtlasAttributeDef(attrDefinition));
            }
            if ( isTrait) {
                AtlasClassificationDef classificationDef = new AtlasClassificationDef(name, description, "1.0", attrDefs, ImmutableSet.of(TaxonomyResourceProvider.TAXONOMY_TERM_TYPE));
                AtlasTypesDef typesDef = new AtlasTypesDef(ImmutableList.<AtlasEnumDef>of(), ImmutableList.<AtlasStructDef>of(),
                    ImmutableList.of(classificationDef),
                    ImmutableList.<AtlasEntityDef>of());

                typeDefStore.createTypesDef(typesDef);

            } else {
                AtlasEntityDef entityDef = new AtlasEntityDef(name, description, "1.0", attrDefs);
                AtlasTypesDef typesDef = new AtlasTypesDef(ImmutableList.<AtlasEnumDef>of(), ImmutableList.<AtlasStructDef>of(),
                    ImmutableList.<AtlasClassificationDef>of(),
                    ImmutableList.of(entityDef));

                typeDefStore.createTypesDef(typesDef);
            }

        } catch (AtlasBaseException e) {
            if ( e.getAtlasErrorCode() == AtlasErrorCode.TYPE_ALREADY_EXISTS) {
                throw new ResourceAlreadyExistsException(String.format("Type '%s' already exists", name));
            } else {
                throw new CatalogRuntimeException(String.format(
                    "Unable to create type '%s' in type system: %s", name, e), e);
            }
        }
    }
}