/*
 * Copyright 2016-present Open Networking Foundation
 *
 * 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.
 */

package org.onosproject.yms.app.ych.defaultcodecs.xml;

import org.dom4j.Element;
import org.onosproject.yms.app.ydt.YdtExtendedContext;
import org.onosproject.yms.ydt.YdtContext;
import org.onosproject.yms.ydt.YdtContextOperationType;

import java.util.Stack;

import static org.onosproject.yms.app.ych.defaultcodecs.netconf.NetconfCodecConstants.OPERATION;
import static org.onosproject.yms.ydt.YdtContextOperationType.NONE;

/**
 * Represents an codec handler to process the xml content and add
 * element to the stack.
 */
public abstract class XmlCodecHandler {

    /**
     * Sets the namespace and tag name in element tree maintained in stack.
     *
     * @param ydtContext   YDT context
     * @param elementStack element tree stack
     */
    void processXmlContext(YdtContext ydtContext,
                           Stack<Element> elementStack) {

        Element newElement = updateNameAndNamespace(ydtContext,
                                                    elementStack.peek());
        elementStack.push(newElement);
    }

    /**
     * Returns the new element name by updating tag name and namespace.
     *
     * @param ydtContext YDT context node
     * @param xmlElement element in the stack used for adding new element
     * @return new element name by updating tag name and namespace
     */
    Element updateNameAndNamespace(YdtContext ydtContext,
                                   Element xmlElement) {
        String nameSpace = null;
        if (ydtContext.getNamespace() != null) {
            nameSpace = ydtContext.getNamespace();
        }

        String parentNameSpace = null;
        if (ydtContext.getParent() != null) {
            parentNameSpace = ydtContext.getParent().getNamespace();
        }

        Element newElement;
        if (nameSpace != null) {
            newElement = xmlElement.addElement(ydtContext.getName(),
                                               nameSpace);
        } else {
            if (parentNameSpace != null) {
                newElement = xmlElement.addElement(ydtContext.getName(),
                                                   parentNameSpace);
            } else {
                newElement = xmlElement.addElement(ydtContext.getName());
            }
        }

        YdtContextOperationType opType = ((YdtExtendedContext) ydtContext)
                .getYdtContextOperationType();
        if (opType != null && opType != NONE) {
            newElement.addAttribute("nc:" + OPERATION,
                                    opType.toString().toLowerCase());
        }

        return newElement;
    }

    /**
     * Sets the leaf value in the current element maintained in stack.
     * Default behaviour is to do nothing.
     *
     * @param ydtContext      YDT context node
     * @param domElementStack current element node in the stack
     */
    public void setXmlValue(YdtContext ydtContext,
                            Stack<Element> domElementStack) {
    }
}