/*
 * 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.binding.http.xml;

import static javax.xml.stream.XMLStreamConstants.END_ELEMENT;
import static javax.xml.stream.XMLStreamConstants.START_ELEMENT;

import javax.xml.namespace.QName;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;

import org.apache.tuscany.sca.assembly.OperationSelector;
import org.apache.tuscany.sca.assembly.WireFormat;
import org.apache.tuscany.sca.assembly.xml.Constants;
import org.apache.tuscany.sca.assembly.xml.PolicyAttachPointProcessor;
import org.apache.tuscany.sca.binding.http.HTTPBinding;
import org.apache.tuscany.sca.binding.http.HTTPBindingFactory;
import org.apache.tuscany.sca.contribution.ModelFactoryExtensionPoint;
import org.apache.tuscany.sca.contribution.processor.BaseStAXArtifactProcessor;
import org.apache.tuscany.sca.contribution.processor.StAXArtifactProcessor;
import org.apache.tuscany.sca.contribution.processor.StAXAttributeProcessor;
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.core.ExtensionPointRegistry;
import org.apache.tuscany.sca.monitor.Monitor;
import org.apache.tuscany.sca.monitor.Problem;
import org.apache.tuscany.sca.monitor.Problem.Severity;
import org.apache.tuscany.sca.monitor.impl.ProblemImpl;
import org.apache.tuscany.sca.policy.PolicyFactory;

public class HTTPBindingProcessor extends BaseStAXArtifactProcessor implements StAXArtifactProcessor<HTTPBinding> {
    private static final String BINDING_HTTP = "binding.http";
    private static final QName BINDING_HTTP_QNAME = new QName(Constants.SCA10_TUSCANY_NS, BINDING_HTTP);
    
    private static final String NAME = "name";
    private static final String URI = "uri";
    
    private HTTPBindingFactory httpBindingFactory;
    private StAXArtifactProcessor<Object> extensionProcessor;
    private StAXAttributeProcessor<Object> extensionAttributeProcessor;
    private PolicyFactory policyFactory;
    private PolicyAttachPointProcessor policyProcessor;
    private Monitor monitor;

    public HTTPBindingProcessor(ExtensionPointRegistry extensionPoints, 
                                StAXArtifactProcessor extensionProcessor,
                                StAXAttributeProcessor extensionAttributeProcessor, 
                                Monitor monitor) {
        ModelFactoryExtensionPoint modelFactories = extensionPoints.getExtensionPoint(ModelFactoryExtensionPoint.class);
        this.httpBindingFactory = modelFactories.getFactory(HTTPBindingFactory.class);
        this.extensionProcessor = (StAXArtifactProcessor<Object>)extensionProcessor;
        this.extensionAttributeProcessor = extensionAttributeProcessor;
        this.policyFactory = modelFactories.getFactory(PolicyFactory.class);
        this.policyProcessor = new PolicyAttachPointProcessor(policyFactory);
        this.monitor = monitor;
    }
    
    public QName getArtifactType() {
        return BINDING_HTTP_QNAME;
    }
    
    public Class<HTTPBinding> getModelType() {
        return HTTPBinding.class;
    }

    public HTTPBinding read(XMLStreamReader reader) throws ContributionReadException, XMLStreamException {
        HTTPBinding httpBinding = httpBindingFactory.createHTTPBinding();
        
        // Read policies
        policyProcessor.readPolicies(httpBinding, reader);
        
        while(reader.hasNext()) {
            QName elementName = null;
            int event = reader.getEventType();
            switch (event) {
                case START_ELEMENT:
                    elementName = reader.getName();
                     
                     if (BINDING_HTTP_QNAME.equals(elementName)) {
                         String name = getString(reader, NAME);
                         if(name != null) {
                             httpBinding.setName(name);
                         }
                         
                         String uri = getString(reader, URI);
                         if (uri != null) {
                             httpBinding.setURI(uri);
                         }
                     } else {
                         // Read an extension element
                         Object extension = extensionProcessor.read(reader);
                         if (extension != null) {
                             if (extension instanceof WireFormat) {
                                 httpBinding.setRequestWireFormat((WireFormat)extension);
                             } else if(extension instanceof OperationSelector) {
                                 httpBinding.setOperationSelector((OperationSelector)extension);
                             }
                         }
                     }
 
            }
            
            if (event == END_ELEMENT && BINDING_HTTP_QNAME.equals(reader.getName())) {
                break;
            }
            
            // Read the next element
            if (reader.hasNext()) {
                reader.next();
            }
        }

        return httpBinding;
    }

    public void write(HTTPBinding httpBinding, XMLStreamWriter writer) throws ContributionWriteException, XMLStreamException {
        writeStart(writer, BINDING_HTTP_QNAME.getNamespaceURI(), BINDING_HTTP_QNAME.getLocalPart());

        //write policies
        policyProcessor.writePolicyAttributes(httpBinding, writer);
        
        // Write binding name
        if (httpBinding.getName() != null) {
            writer.writeAttribute(NAME, httpBinding.getName());
        }

        // Write binding URI
        if (httpBinding.getURI() != null) {
            writer.writeAttribute(URI, httpBinding.getURI());
        }
        
        if ( httpBinding.getRequestWireFormat() != null ) {
        	extensionProcessor.write(httpBinding.getRequestWireFormat(), writer);
        }
        
        if ( httpBinding.getOperationSelector() != null ) {
        	extensionProcessor.write(httpBinding.getOperationSelector(), writer);
        }
        writeEnd(writer);
    }


    public void resolve(HTTPBinding model, ModelResolver resolver) throws ContributionResolveException {      
        policyProcessor.resolvePolicies(model, resolver);    
    }
    
    /**
     * Report a error.
     * 
     * @param problems
     * @param message
     * @param model
     */
    private void error(String message, Object model, Object... messageParameters) {
         if (monitor != null) {
                Problem problem = new ProblemImpl(this.getClass().getName(), "binding-http-validation-messages", Severity.ERROR, model, message, (Object[])messageParameters);
                monitor.problem(problem);
         }
    }

}