/*
 * Copyright 2010 the original author or authors.
 *
 * 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.gradle.messaging.remote.internal;

import org.gradle.messaging.dispatch.Dispatch;
import org.gradle.messaging.dispatch.MethodInvocation;

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

public class MethodInvocationUnmarshallingDispatch implements Dispatch<Message> {
    private final Dispatch<? super MethodInvocation> dispatch;
    private final ClassLoader classLoader;
    private final Map<Object, Method> methods = new HashMap<Object, Method>();

    public MethodInvocationUnmarshallingDispatch(Dispatch<? super MethodInvocation> dispatch, ClassLoader classLoader) {
        this.dispatch = dispatch;
        this.classLoader = classLoader;
    }

    public void dispatch(Message message) {
        if (message instanceof MethodMetaInfo) {
            MethodMetaInfo methodMetaInfo = (MethodMetaInfo) message;
            Method method = methodMetaInfo.findMethod(classLoader);
            methods.put(methodMetaInfo.getKey(), method);
        } else if (message instanceof RemoteMethodInvocation) {
            RemoteMethodInvocation remoteMethodInvocation = (RemoteMethodInvocation) message;
            Method method = methods.get(remoteMethodInvocation.getKey());
            if (method == null) {
                throw new IllegalStateException("Received a method invocation message for an unknown method.");
            }
            MethodInvocation methodInvocation = new MethodInvocation(method,
                    remoteMethodInvocation.getArguments());
            dispatch.dispatch(methodInvocation);
        } else {
            throw new IllegalStateException(String.format("Received an unknown message %s.", message));
        }
    }
}
