/*
 * Copyright 2008 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.wamblee.system.graph.component;

import org.wamblee.system.core.SystemAssemblyException;
import org.wamblee.system.graph.Edge;
import org.wamblee.system.graph.Graph;
import org.wamblee.system.graph.Node;
import org.wamblee.system.graph.Visitor;

import java.util.List;

/**
 * Visitor that checks whether all externally provided interfaces are actually
 * provided by any of the internal components.
 * 
 * @author Erik Brakkee
 */
public class CheckExternallyProvidedVisitor implements Visitor {
    private Graph graph;

    /**
     * Constructs the visitor.
     * 
     * @param aGraph
     *            Component graph.
     */
    public CheckExternallyProvidedVisitor(Graph aGraph) {
        graph = aGraph;
    }

    @Override
    public void visitEdge(Edge aEdge) {
        // Empty.
    }

    @Override
    public void visitNode(Node aNode) {
        if (aNode instanceof ExternalProvidedInterfaceNode) {
            ExternalProvidedInterfaceNode provided = (ExternalProvidedInterfaceNode) aNode;
            List<Edge> edges = graph.findOutgoing(provided);

            if (edges.size() > 2) {
                createDuplicateException(
                    "External provided interfaces has multiple internal matches",
                    aNode, edges);
            }

            if (edges.size() == 0) {
                throw new SystemAssemblyException(
                    aNode +
                        ": external provded interface is not provided by any of the internal components");
            }
        }
    }

    private void createDuplicateException(String aMsg, Node aNode,
        List<Edge> edges) {
        StringBuffer buf = new StringBuffer();
        buf.append(aNode + ": " + aMsg + ": ");

        for (Edge edge : edges) {
            buf.append(edge.getTo() + "/ ");
        }

        throw new SystemAssemblyException(buf.toString());
    }
}