/*
 * 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.osgi.runtime;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.IdentityHashMap;
import java.util.Map;

import org.apache.tuscany.sca.databinding.DataBinding;
import org.apache.tuscany.sca.databinding.DataBindingExtensionPoint;
import org.apache.tuscany.sca.implementation.osgi.context.OSGiAnnotations;
import org.apache.tuscany.sca.interfacedef.DataType;
import org.apache.tuscany.sca.interfacedef.Operation;
import org.apache.tuscany.sca.invocation.DataExchangeSemantics;
import org.apache.tuscany.sca.invocation.Message;
import org.apache.tuscany.sca.runtime.RuntimeComponentService;

/**
 * An interceptor to enforce pass-by-value semantics for remotable interfaces
 *
 * @version $Rev$ $Date$
 */
public class OSGiRemotableInvoker extends OSGiTargetInvoker implements DataExchangeSemantics {

    private DataBindingExtensionPoint registry;
    private Operation operation;
    private OSGiAnnotations osgiAnnotations;

    /**
     * @param registry
     * @param operation
     * @param method
     * @param component
     */
    public OSGiRemotableInvoker(OSGiAnnotations osgiAnnotations,
                                DataBindingExtensionPoint registry,
                                Operation operation,
                                OSGiImplementationProvider provider,
                                RuntimeComponentService service) {
        super(operation, provider, service);
        this.osgiAnnotations = osgiAnnotations;
        this.registry = registry;
        this.operation = operation;
    }

    @Override
    public Object invokeMethod(Object targetObject, Method m, Message msg) throws InvocationTargetException {

        Object result;
        if (osgiAnnotations.isAllowsPassByReference(targetObject, m)) {
            result = super.invokeMethod(targetObject, m, msg);
        } else {
            Object obj = msg.getBody();
            msg.setBody(copy((Object[])obj));

            result = super.invokeMethod(targetObject, m, msg);

            if (operation.getOutputType() != null) {
                String dataBindingId = operation.getOutputType().getDataBinding();
                DataBinding dataBinding = registry.getDataBinding(dataBindingId);
                result = copy(result, operation.getOutputType(), dataBinding);
            }
        }
        return result;
    }

    public Object[] copy(Object[] args) {
        if (args == null) {
            return null;
        }
        Object[] copiedArgs = new Object[args.length];
        Map<Object, Object> map = new IdentityHashMap<Object, Object>();
        for (int i = 0; i < args.length; i++) {
            if (args[i] == null) {
                copiedArgs[i] = null;
            } else {
                Object copiedArg = map.get(args[i]);
                if (copiedArg != null) {
                    copiedArgs[i] = copiedArg;
                } else {
                    DataType dt = operation.getInputType().getLogical().get(i);
                    String dataBindingId = dt.getDataBinding();
                    DataBinding dataBinding = registry.getDataBinding(dataBindingId);
                    copiedArg = copy(args[i], dt, dataBinding);
                    map.put(args[i], copiedArg);
                    copiedArgs[i] = copiedArg;
                }
            }
        }
        return copiedArgs;
    }

    public Object copy(Object arg, DataType dataType, DataBinding argDataBinding) {
        if (arg == null) {
            return null;
        }
        Object copiedArg;
        if (argDataBinding != null) {
            copiedArg = argDataBinding.copy(arg, dataType, operation);
        } else {
            copiedArg = arg;
            dataType = registry.introspectType(arg, operation);
            if (dataType != null) {
                DataBinding binding = registry.getDataBinding(dataType.getDataBinding());
                if (binding != null) {
                    copiedArg = binding.copy(arg, dataType, operation);
                }
            }
            // FIXME: What to do if it's not recognized?
        }
        return copiedArg;
    }

    /**
     * @see org.apache.tuscany.sca.invocation.PassByValueAware#allowsPassByReference()
     */
    public boolean allowsPassByReference() {
        return true;
    }

}