/*
 * 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
 *
 *   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.apache.tuscany.sca.policy.recoveryrules;

import javax.xml.namespace.QName;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;
import org.apache.axiom.om.OMAbstractFactory;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMFactory;
import org.apache.tuscany.sca.contribution.processor.StAXArtifactProcessor;
import org.apache.tuscany.sca.contribution.resolver.ModelResolver;
import org.apache.tuscany.sca.contribution.service.ContributionReadException;
import org.apache.tuscany.sca.contribution.service.ContributionResolveException;
import org.apache.tuscany.sca.contribution.service.ContributionWriteException;
import org.apache.tuscany.sca.guardian.Constants;
import org.apache.tuscany.sca.contribution.ModelFactoryExtensionPoint;
import org.apache.tuscany.sca.monitor.Monitor;

public class RecoveryRulesPolicyProcessor implements StAXArtifactProcessor<RecoveryRulesPolicy>, Constants {

    private static final QName RECOVERY_RULES_POLICY_QNAME = RecoveryRulesPolicy.RECOVERY_RULES_POLICY_QNAME;

    public RecoveryRulesPolicyProcessor(ModelFactoryExtensionPoint modelFactories, Monitor monitor) {
    }

    public RecoveryRulesPolicy read(XMLStreamReader reader) throws ContributionReadException, XMLStreamException {

        RecoveryRulesPolicy policy = new RecoveryRulesPolicy();
        QName name = null;
        String ruleName = null;
        OMElement ruleElement = null;
        while (reader.hasNext()) {

            if (reader.isStartElement()) {

                name = reader.getName();
                if (RULE.equals(name.getLocalPart())) {

                    ruleName = reader.getAttributeValue(null, Constants.NAME);
                    ruleElement = loadElement(reader);

                    policy.getRuleElements().put(ruleName, ruleElement);
                }
            } else if (reader.isEndElement()) {
                if (RECOVERY_RULES_POLICY_QNAME.equals(reader.getName())) {
                    break;
                }
            }

            reader.next();
        }

        return policy;
    }

    public void write(RecoveryRulesPolicy policy, XMLStreamWriter writer) throws ContributionWriteException, XMLStreamException {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    public QName getArtifactType() {
        return RECOVERY_RULES_POLICY_QNAME;
    }

    public void resolve(RecoveryRulesPolicy arg0, ModelResolver arg1) throws ContributionResolveException {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    public Class<RecoveryRulesPolicy> getModelType() {
        return RecoveryRulesPolicy.class;
    }

    private OMElement loadElement(XMLStreamReader reader) throws XMLStreamException {
        OMFactory fac = OMAbstractFactory.getOMFactory();
        OMElement head = fac.createOMElement(reader.getName());

        //Load the attributes for the rule tag
        loadAttributes(reader, head, fac);

        OMElement current = head;
        while (true) {

            switch (reader.next()) {
                case XMLStreamConstants.START_ELEMENT:

                    QName name = new QName(reader.getName().getLocalPart());
                    OMElement child = fac.createOMElement(name, current);

                    int count = reader.getNamespaceCount();
                    for (int i = 0; i < count; i++) {
                        String prefix = reader.getNamespacePrefix(i);
                        String ns = reader.getNamespaceURI(i);
                        child.declareNamespace(ns, prefix);
                    }

                    if (!"".equals(name.getNamespaceURI())) {
                        child.declareNamespace(name.getNamespaceURI(), name.getPrefix());
                    }

                    // add the attributes for this element
                    loadAttributes(reader, child, fac);
                    current = child;
                    break;
                case XMLStreamConstants.CDATA:
                    fac.createOMText(current, reader.getText());
                    break;
                case XMLStreamConstants.CHARACTERS:
                    String text = reader.getText().trim();
                    if (text.length() != 0) {
                        fac.createOMText(current, reader.getText());
                    }
                    break;
                case XMLStreamConstants.END_ELEMENT:
                    if (current == head) {
                        return head;
                    } else {
                        current = (OMElement) current.getParent();
                    }
            }
        }
    }

    private void loadAttributes(XMLStreamReader reader, OMElement elem, OMFactory fac) {
        int count = reader.getAttributeCount();
        for (int i = 0; i < count; i++) {
            String ns = reader.getAttributeNamespace(i);
            String prefix = reader.getAttributePrefix(i);
            String qname = reader.getAttributeLocalName(i);
            String value = reader.getAttributeValue(i);

            if (ns != null) {
                elem.addAttribute(qname, value, fac.createOMNamespace(ns, prefix));
                elem.declareNamespace(ns, prefix);
            } else {
                elem.addAttribute(qname, value, null);
            }
        }
    }
}