/*
 * 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.implementation.java.xml;

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

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.Map;

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.AssemblyFactory;
import org.apache.tuscany.sca.assembly.ComponentType;
import org.apache.tuscany.sca.assembly.ConfiguredOperation;
import org.apache.tuscany.sca.assembly.Extension;
import org.apache.tuscany.sca.assembly.ExtensionFactory;
import org.apache.tuscany.sca.assembly.OperationsConfigurator;
import org.apache.tuscany.sca.assembly.Property;
import org.apache.tuscany.sca.assembly.Reference;
import org.apache.tuscany.sca.assembly.Service;
import org.apache.tuscany.sca.assembly.xml.ConfiguredOperationProcessor;
import org.apache.tuscany.sca.assembly.xml.Constants;
import org.apache.tuscany.sca.assembly.xml.PolicyAttachPointProcessor;
import org.apache.tuscany.sca.contribution.ModelFactoryExtensionPoint;
import org.apache.tuscany.sca.contribution.processor.StAXArtifactProcessor;
import org.apache.tuscany.sca.contribution.processor.StAXAttributeProcessor;
import org.apache.tuscany.sca.contribution.resolver.ClassReference;
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.implementation.java.IntrospectionException;
import org.apache.tuscany.sca.implementation.java.JavaImplementation;
import org.apache.tuscany.sca.implementation.java.JavaImplementationFactory;
import org.apache.tuscany.sca.implementation.java.impl.JavaElementImpl;
import org.apache.tuscany.sca.implementation.java.introspect.impl.JavaIntrospectionHelper;
import org.apache.tuscany.sca.interfacedef.Interface;
import org.apache.tuscany.sca.interfacedef.java.JavaInterface;
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.IntentAttachPointTypeFactory;
import org.apache.tuscany.sca.policy.PolicyFactory;

/**
 *
 * @version $Rev$ $Date$
 */
public class JavaImplementationProcessor implements StAXArtifactProcessor<JavaImplementation>,
    JavaImplementationConstants {

    private AssemblyFactory assemblyFactory;
    private PolicyFactory policyFactory;
    private ExtensionFactory extensionFactory;
    private JavaImplementationFactory javaFactory;
    private PolicyAttachPointProcessor policyProcessor;
    private IntentAttachPointTypeFactory  intentAttachPointTypeFactory;
    private ConfiguredOperationProcessor configuredOperationProcessor;
    private StAXAttributeProcessor<Object> extensionAttributeProcessor;
    private Monitor monitor;

    public JavaImplementationProcessor(ModelFactoryExtensionPoint modelFactories,
                                       StAXArtifactProcessor extensionProcessor,
                                       StAXAttributeProcessor extensionAttributeProcessor,
                                       Monitor monitor) {
        this.assemblyFactory = modelFactories.getFactory(AssemblyFactory.class);
        this.policyFactory = modelFactories.getFactory(PolicyFactory.class);
        this.extensionFactory = modelFactories.getFactory(ExtensionFactory.class);
        this.javaFactory = modelFactories.getFactory(JavaImplementationFactory.class);
        this.policyProcessor = new PolicyAttachPointProcessor(policyFactory);
        this.intentAttachPointTypeFactory = modelFactories.getFactory(IntentAttachPointTypeFactory.class);
        this.monitor = monitor;
        this.configuredOperationProcessor = new ConfiguredOperationProcessor(modelFactories, this.monitor);
        this.extensionAttributeProcessor = extensionAttributeProcessor;
    }

    /**
     * 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(), "impl-javaxml-validation-messages", Severity.ERROR, model, message,(Object[])messageParameters);
    	     monitor.problem(problem);
    	 }
     }

     /**
      * Report a exception.
      *
      * @param problems
      * @param message
      * @param model
      */
      private void error(String message, Object model, Exception ex) {
     	 if (monitor != null) {
     		 Problem problem = new ProblemImpl(this.getClass().getName(), "impl-javaxml-validation-messages", Severity.ERROR, model, message, ex);
     	     monitor.problem(problem);
     	 }
      }

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

        // Read an <implementation.java>
        JavaImplementation javaImplementation = javaFactory.createJavaImplementation();

        /*if ( javaImplementation instanceof PolicySetAttachPoint ) {
            IntentAttachPointType implType = intentAttachPointTypeFactory.createImplementationType();
            implType.setName(getArtifactType());
            implType.setUnresolved(true);
            ((PolicySetAttachPoint)javaImplementation).setType(implType);
        }*/

        javaImplementation.setUnresolved(true);
        javaImplementation.setName(reader.getAttributeValue(null, CLASS));

        // Read policies
        policyProcessor.readPolicies(javaImplementation, reader);

        // Handle extended attributes
        for (int a = 0; a < reader.getAttributeCount(); a++) {
            QName attributeName = reader.getAttributeName(a);
            if( attributeName.getNamespaceURI() != null && attributeName.getNamespaceURI().length() > 0) {
                if( (! Constants.SCA10_NS.equals(attributeName.getNamespaceURI()) &&
                    (! Constants.SCA10_TUSCANY_NS.equals(attributeName.getNamespaceURI()) ))) {
                    Object attributeValue = extensionAttributeProcessor.read(attributeName, reader);
                    Extension attributeExtension;
                    if (attributeValue instanceof Extension) {
                        attributeExtension = (Extension) attributeValue;
                    } else {
                        attributeExtension = extensionFactory.createExtension(attributeName, attributeValue, true);
                    }
                    javaImplementation.getAttributeExtensions().add(attributeExtension);
                }
            }
        }



        // read operation elements if exists or skip unto end element
        int event;
        ConfiguredOperation confOp = null;
        while (reader.hasNext()) {
            event = reader.next();
            switch ( event ) {
                case START_ELEMENT  : {
                    if ( Constants.OPERATION_QNAME.equals(reader.getName()) ) {
                        confOp = configuredOperationProcessor.read(reader);
                        if ( confOp != null ) {
                            ((OperationsConfigurator)javaImplementation).getConfiguredOperations().add(confOp);
                        }
                    }
                }
                break;
            }

            if (event == END_ELEMENT && IMPLEMENTATION_JAVA_QNAME.equals(reader.getName())) {
                break;
            }
        }
        return javaImplementation;
    }

    public void write(JavaImplementation javaImplementation, XMLStreamWriter writer) throws ContributionWriteException,
        XMLStreamException {

        // Write an <implementation.java>
        writer.writeStartElement(Constants.SCA10_NS, IMPLEMENTATION_JAVA);
        policyProcessor.writePolicyAttributes(javaImplementation, writer);

        if (javaImplementation.getName() != null) {
            writer.writeAttribute(CLASS, javaImplementation.getName());
        }

        // Write extended attributes
        for(Extension extension : javaImplementation.getAttributeExtensions()) {
            if(extension.isAttribute()) {
                extensionAttributeProcessor.write(extension, writer);
            }
        }

        writer.writeEndElement();
    }

    public void resolve(JavaImplementation javaImplementation, ModelResolver resolver)
        throws ContributionResolveException {

        ClassReference classReference = new ClassReference(javaImplementation.getName());
        classReference = resolver.resolveModel(ClassReference.class, classReference);
        Class javaClass = classReference.getJavaClass();
        if (javaClass == null) {
        	error("ClassNotFoundException", resolver, javaImplementation.getName());
            //throw new ContributionResolveException(new ClassNotFoundException(javaImplementation.getName()));
        	return;
        }

        javaImplementation.setJavaClass(javaClass);

        try {
            javaFactory.createJavaImplementation(javaImplementation, javaImplementation.getJavaClass());
        } catch (IntrospectionException e) {
        	ContributionResolveException ce = new ContributionResolveException(e);
        	error("ContributionResolveException", javaFactory, ce);
            //throw ce;
        	return;
        }

        javaImplementation.setUnresolved(false);
        mergeComponentType(resolver, javaImplementation);

        // FIXME the introspector should always create at least one service
        if (javaImplementation.getServices().isEmpty()) {
            javaImplementation.getServices().add(assemblyFactory.createService());
        }
    }

    private JavaElementImpl getMemeber(JavaImplementation impl, String name, Class<?> type) {
        String setter = JavaIntrospectionHelper.toSetter(name);
        try {
            Method method = impl.getJavaClass().getDeclaredMethod(setter, type);
            int mod = method.getModifiers();
            if ((Modifier.isPublic(mod) || Modifier.isProtected(mod)) && (!Modifier.isStatic(mod))) {
                return new JavaElementImpl(method, 0);
            }
        } catch (NoSuchMethodException e) {
            Field field;
            try {
                field = impl.getJavaClass().getDeclaredField(name);
                int mod = field.getModifiers();
                if ((Modifier.isPublic(mod) || Modifier.isProtected(mod)) && (!Modifier.isStatic(mod))) {
                	return new JavaElementImpl(field);
                }
            } catch (NoSuchFieldException e1) {
                // Ignore
            }
        }
        return null;
    }

    /**
     * Merge the componentType from introspection and external file
     * @param resolver
     * @param impl
     */
    private void mergeComponentType(ModelResolver resolver, JavaImplementation impl) {
        // FIXME: Need to clarify how to merge
        ComponentType componentType = getComponentType(resolver, impl);
        if (componentType != null && !componentType.isUnresolved()) {
            Map<String, Reference> refMap = new HashMap<String, Reference>();
            for (Reference ref : impl.getReferences()) {
                refMap.put(ref.getName(), ref);
            }
            for (Reference reference : componentType.getReferences()) {
                refMap.put(reference.getName(), reference);
            }
            impl.getReferences().clear();
            impl.getReferences().addAll(refMap.values());

            // Try to match references by type
            Map<String, JavaElementImpl> refMembers = impl.getReferenceMembers();
            for (Reference ref : impl.getReferences()) {
                if (ref.getInterfaceContract() != null) {
                    Interface i = ref.getInterfaceContract().getInterface();
                    if (i instanceof JavaInterface) {
                        Class<?> type = ((JavaInterface)i).getJavaClass();
                        if (!refMembers.containsKey(ref.getName())) {
                            JavaElementImpl e = getMemeber(impl, ref.getName(), type);
                            if (e != null) {
                                refMembers.put(ref.getName(), e);
                            }
                        }
                    }
                }
            }

            Map<String, Service> serviceMap = new HashMap<String, Service>();
            for (Service svc : impl.getServices()) {
                serviceMap.put(svc.getName(), svc);
            }
            for (Service service : componentType.getServices()) {
                serviceMap.put(service.getName(), service);
            }
            impl.getServices().clear();
            impl.getServices().addAll(serviceMap.values());

            Map<String, Property> propMap = new HashMap<String, Property>();
            for (Property prop : impl.getProperties()) {
                propMap.put(prop.getName(), prop);
            }
            for (Property property : componentType.getProperties()) {
                propMap.put(property.getName(), property);
            }
            impl.getProperties().clear();
            impl.getProperties().addAll(propMap.values());

            if (componentType.getConstrainingType() != null) {
                impl.setConstrainingType(componentType.getConstrainingType());
            }
        }
    }

    private ComponentType getComponentType(ModelResolver resolver, JavaImplementation impl) {
        String className = impl.getJavaClass().getName();
        String componentTypeURI = className.replace('.', '/') + ".componentType";
        ComponentType componentType = assemblyFactory.createComponentType();
        componentType.setUnresolved(true);
        componentType.setURI(componentTypeURI);
        componentType = resolver.resolveModel(ComponentType.class, componentType);
        if (!componentType.isUnresolved()) {
            return componentType;
        }
        return null;
    }

    public QName getArtifactType() {
        return IMPLEMENTATION_JAVA_QNAME;
    }

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

}