/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 2017-2019 AT&T Intellectual Property. All rights reserved.
 * Copyright © 2017-2019 European Software Marketing Ltd.
 * ================================================================================
 * Licensed 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
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * 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.
 * ============LICENSE_END=========================================================
 */

package org.onap.aai.babel.xml.generator.api;

import java.io.StringWriter;
import java.util.List;
import java.util.Set;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import org.onap.aai.babel.logging.ApplicationMsgs;
import org.onap.aai.babel.logging.LogHelper;
import org.onap.aai.babel.xml.generator.XmlArtifactGenerationException;
import org.onap.aai.babel.xml.generator.model.Resource;
import org.onap.aai.babel.xml.generator.model.Service;
import org.onap.aai.babel.xml.generator.model.Widget;
import org.onap.aai.babel.xml.generator.xsd.Model;
import org.onap.aai.babel.xml.generator.xsd.ModelElement;
import org.onap.aai.babel.xml.generator.xsd.ModelElements;
import org.onap.aai.babel.xml.generator.xsd.ModelVer;
import org.onap.aai.babel.xml.generator.xsd.ModelVers;
import org.onap.aai.babel.xml.generator.xsd.Relationship;
import org.onap.aai.babel.xml.generator.xsd.RelationshipData;
import org.onap.aai.babel.xml.generator.xsd.RelationshipList;
import org.onap.aai.cl.api.Logger;
import org.w3c.dom.DOMException;

/**
 * Implementation of the {@link AaiModelGenerator} which generates the XML models from the Service/Resource/Widget java
 * models.
 */
public class AaiModelGeneratorImpl implements AaiModelGenerator {
    private static Logger log = LogHelper.INSTANCE;

    /**
     * Method to generate the AAI model for a Service.
     *
     * @param service
     *            Java object model representing an AAI {@link Service} model
     * @return XML representation of the service model in String format
     * @throws XmlArtifactGenerationException 
     */
    @Override
    public String generateModelFor(Service service) throws XmlArtifactGenerationException {
        // Create a JAXB Model for AAI service model
        Model aaiServiceModel = new Model();
        log.debug("Generating Model for Service with ModelName: " + service.getModelName());
        // after new model
        aaiServiceModel.setModelInvariantId(service.getModelId());
        aaiServiceModel.setModelVers(new ModelVers());
        ModelVer modelVer = new ModelVer();
        modelVer.setModelDescription(service.getModelDescription());
        modelVer.setModelName(service.getModelName());
        modelVer.setModelVersion(service.getModelVersion());
        modelVer.setModelVersionId(service.getModelNameVersionId());
        modelVer.setModelElements(new ModelElements());
        ModelElements modelElements = modelVer.getModelElements();
        // Populate basic model details
        aaiServiceModel.setModelType(service.getModelType().name().toLowerCase()); // Using enum name as model type
        List<ModelElement> modelElementList = modelElements.getModelElement();

        // Add service base widget model element
        ModelElement serviceWidgetModelRelationshipElement = createRelationshipModelElement(
                getNewDataDelFlagValue(service.getDeleteFlag()), service.getWidgetId(), service.getWidgetInvariantId());
        modelElementList.add(serviceWidgetModelRelationshipElement);

        // Add the resource model elements
        ModelElements serviceModelElements = serviceWidgetModelRelationshipElement.getModelElements();
        List<ModelElement> serviceModelElementList = serviceModelElements.getModelElement();
        Set<Resource> serviceResources = service.getResources();
        if (serviceResources != null && !serviceResources.isEmpty()) {
            for (Resource resourceModel : serviceResources) {
                ModelElement aaiResourceModelElement =
                        createRelationshipModelElement(getNewDataDelFlagValue(resourceModel.getDeleteFlag()),
                                resourceModel.getModelNameVersionId(), resourceModel.getModelId());
                serviceModelElementList.add(aaiResourceModelElement);
            }
        }

        // Add the widget model elements
        Set<Widget> serviceWidgets = service.getWidgets();
        if (serviceWidgets != null && !serviceWidgets.isEmpty()) {
            for (Widget widgetModel : serviceWidgets) {
                ModelElement widgetModelElement =
                        createRelationshipModelElement(getNewDataDelFlagValue(widgetModel.getDeleteFlag()),
                                widgetModel.getId(), widgetModel.getWidgetId());
                serviceModelElementList.add(widgetModelElement);
            }
        }
        ModelVers modelVers = aaiServiceModel.getModelVers();
        List<ModelVer> modelVerList = modelVers.getModelVer();
        modelVerList.add(modelVer);
        return getModelAsString(aaiServiceModel);
    }

    /**
     * Method to generate the AAI model for a Resource.
     *
     * @param resource
     *            Java object model representing an AAI {@link Resource} model
     * @return XML representation of the resource model in String format
     * @throws XmlArtifactGenerationException 
     */
    @Override
    public String generateModelFor(Resource resource) throws XmlArtifactGenerationException {
        // Create a JAXB Model for AAI Resource model
        Model aaiResourceModel = new Model();
        log.debug("Generating Model for Resource with ModelName: " + resource.getModelName());
        aaiResourceModel.setModelInvariantId(resource.getModelId());
        aaiResourceModel.setModelVers(new ModelVers());
        ModelVer modelVer = new ModelVer();
        modelVer.setModelDescription(resource.getModelDescription());
        modelVer.setModelName(resource.getModelName());
        modelVer.setModelVersion(resource.getModelVersion());
        modelVer.setModelVersionId(resource.getModelNameVersionId());
        modelVer.setModelElements(new ModelElements());
        ModelElements modelElements = modelVer.getModelElements();
        aaiResourceModel.setModelType(resource.getModelType().name().toLowerCase()); // Using enum name as model type
        List<ModelElement> modelElementList = modelElements.getModelElement();

        // Add resource base widget model element
        ModelElement resourceWidgetModelRelationshipElement =
                createRelationshipModelElement(getNewDataDelFlagValue(resource.getDeleteFlag()), resource.getWidgetId(),
                        resource.getWidgetInvariantId());
        modelElementList.add(resourceWidgetModelRelationshipElement);

        // Add the child resources to the base widget model element list
        ModelElements baseResourceWidgetModelElements = resourceWidgetModelRelationshipElement.getModelElements();
        List<ModelElement> baseResourceWidgetModelElementList = baseResourceWidgetModelElements.getModelElement();
        Set<Resource> childResources = resource.getResources();
        if (childResources != null && !childResources.isEmpty()) {
            for (Resource childResourceModel : childResources) {
                ModelElement aaiChildResourceModelElement =
                        createRelationshipModelElement(getNewDataDelFlagValue(childResourceModel.getDeleteFlag()),
                                childResourceModel.getModelNameVersionId(), childResourceModel.getModelId());
                baseResourceWidgetModelElementList.add(aaiChildResourceModelElement);
            }
        }
        // Add resource widgets/resources to the resource widget model relationship element
        Set<Widget> resourceWidgets = resource.getWidgets();
        if (resourceWidgets != null && !resourceWidgets.isEmpty()) {
            generateWidgetChildren(resourceWidgetModelRelationshipElement, resourceWidgets);
        }

        ModelVers modelVers = aaiResourceModel.getModelVers();
        List<ModelVer> modelVerList = modelVers.getModelVer();
        modelVerList.add(modelVer);
        return getModelAsString(aaiResourceModel);
    }

    /**
     * Method to create the <model-element></model-element> holding the relationship value for a resource/widget model.
     *
     * @param newDataDelFlag
     *            Value of the <new-data-del-flag></new-data-del-flag> attribute for a widget/resource in the model xml
     * @param relationshipValue
     *            Value of the <relationship-value></relationship-value> attribute for the widget/resource in the model
     *            xml
     * @return Java object representation for the <model-element></model-element> holding the relationship
     */
    private ModelElement createRelationshipModelElement(String newDataDelFlag, String modelVersionId,
            String modelInvariantId) {
        ModelElement relationshipModelElement = new ModelElement();
        relationshipModelElement.setNewDataDelFlag(newDataDelFlag); // Set new-data-del-flag value
        relationshipModelElement.setCardinality("unbounded");
        RelationshipList relationShipList = new RelationshipList();
        final List<Relationship> relationships = relationShipList.getRelationship();
        Relationship relationship = new Relationship();
        relationship.setRelatedTo("model-ver");
        List<RelationshipData> relationshipDataList = relationship.getRelationshipData();

        RelationshipData modelVersionRelationshipData = new RelationshipData();
        modelVersionRelationshipData.setRelationshipKey("model-ver.model-version-id");
        modelVersionRelationshipData.setRelationshipValue(modelVersionId); // Set the widget/resource name-version-uuid
        // as value
        relationshipDataList.add(modelVersionRelationshipData);
        RelationshipData modelInvariantRelationshipData = new RelationshipData();
        modelInvariantRelationshipData.setRelationshipKey("model.model-invariant-id");
        modelInvariantRelationshipData.setRelationshipValue(modelInvariantId);
        relationshipDataList.add(modelInvariantRelationshipData);
        relationships.add(relationship);
        relationshipModelElement.setRelationshipList(relationShipList);
        relationshipModelElement.setModelElements(new ModelElements());
        return relationshipModelElement;
    }

    /**
     * Method to create the child model elements of the widget. Handles the generation of recursive child widget
     * elements (if any)
     *
     * @param parent
     *            Reference to the parent widget model element
     * @param widgetChildrenSet
     *            Set of children obtained from the tosca/widget definition
     */
    private void generateWidgetChildren(ModelElement parent, Set<Widget> widgetChildrenSet) {
        for (Widget widget : widgetChildrenSet) {
            Set<Widget> widgetSubChildren = widget.getWidgets();
            if (widgetSubChildren != null && !widgetSubChildren.isEmpty()) {
                ModelElement widgetChildRelationshipElement = createRelationshipModelElement(
                        getNewDataDelFlagValue(widget.getDeleteFlag()), widget.getId(), widget.getWidgetId());
                // Recursive call for getting the children of widgets (if any)
                generateWidgetChildren(widgetChildRelationshipElement, widgetSubChildren);
                parent.getModelElements().getModelElement().add(widgetChildRelationshipElement);
            } else {
                ModelElement widgetChildRelationshipElement = createRelationshipModelElement(
                        getNewDataDelFlagValue(widget.getDeleteFlag()), widget.getId(), widget.getWidgetId());
                parent.getModelElements().getModelElement().add(widgetChildRelationshipElement);
            }
        }
    }

    /**
     * Converts the data delete flag value from boolean to String as per AAI model.
     *
     * @param delFlag
     *            Boolean value as true/false from the annotation
     * @return Converted value to a flag as per AAI model
     */
    private String getNewDataDelFlagValue(boolean delFlag) {
        return delFlag ? "T" : "F";
    }

    /**
     * JAXB marshalling helper method to convert the Java object model to XML String.
     *
     * @param model
     *            Java Object model of a service/widget/resource
     * @return XML representation of the Java model in String format
     */
    private String getModelAsString(Model model) {
        JAXBContext jaxbContext;
        StringWriter modelStringWriter = new StringWriter();
        try {
            jaxbContext = JAXBContext.newInstance(Model.class);
            Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
            jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
            jaxbMarshaller.setProperty(Marshaller.JAXB_ENCODING, "US-ASCII");
            jaxbMarshaller.setProperty(Marshaller.JAXB_FRAGMENT, Boolean.TRUE);
            jaxbMarshaller.marshal(model, modelStringWriter);
        } catch (JAXBException jaxbException) {
            log.error(ApplicationMsgs.INVALID_CSAR_FILE, jaxbException);
            throw new DOMException(DOMException.SYNTAX_ERR, jaxbException.getMessage());
        }

        return modelStringWriter.toString();
    }
}