/*
 * 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.plugin.itest;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;

import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.factory.ArtifactFactory;
import org.apache.maven.artifact.metadata.ArtifactMetadataRetrievalException;
import org.apache.maven.artifact.metadata.ArtifactMetadataSource;
import org.apache.maven.artifact.metadata.ResolutionGroup;
import org.apache.maven.artifact.repository.ArtifactRepository;
import org.apache.maven.artifact.resolver.ArtifactNotFoundException;
import org.apache.maven.artifact.resolver.ArtifactResolutionException;
import org.apache.maven.artifact.resolver.ArtifactResolutionResult;
import org.apache.maven.artifact.resolver.ArtifactResolver;
import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;
import org.apache.tuscany.host.runtime.InitializationException;

import org.osoa.sca.CompositeContext;
import org.osoa.sca.CurrentCompositeContext;

/**
 * @version $Rev$ $Date$
 * @goal start
 * @phase pre-integration-test
 */
public class TuscanyStartMojo extends AbstractMojo {

    public class MavenEmbeddedArtifactRepository implements org.apache.tuscany.spi.services.artifact.ArtifactRepository {
        public static final String COMPONENT_NAME = "MavenEmbeddedArtifactRepository";

        public void resolve(org.apache.tuscany.spi.services.artifact.Artifact artifact) {
            resolveTransitively(artifact);
        }

        public void resolve(Collection artifacts) {
            for (Object a : artifacts) {
                resolve((Artifact)a);
            }
        }

        /**
         * Resolves the dependencies transitively.
         * 
         * @param rootArtifact Artifact whose dependencies need to be resolved.
         */
        public boolean resolveTransitively(org.apache.tuscany.spi.services.artifact.Artifact rootArtifact) {

            org.apache.maven.artifact.Artifact mavenRootArtifact =
                artifactFactory.createArtifact(rootArtifact.getGroup(), rootArtifact.getName(), rootArtifact
                    .getVersion(), org.apache.maven.artifact.Artifact.SCOPE_RUNTIME, rootArtifact.getType());

            try {

                if (resolve(mavenRootArtifact)) {
                    rootArtifact.setUrl(mavenRootArtifact.getFile().toURL());
                    if (resolveDependencies(rootArtifact, mavenRootArtifact)) {
                        return true;
                    } else {
                        return false;
                    }
                } else {
                    return false;
                }
            } catch (MalformedURLException ex) {
                throw new IllegalArgumentException(ex);
            }

        }

        /*
         * Resolves the artifact.
         */
        private boolean resolve(org.apache.maven.artifact.Artifact mavenRootArtifact) {

            try {
                resolver.resolve(mavenRootArtifact, remoteRepositories, localRepository);
                return true;
            } catch (ArtifactResolutionException ex) {
                return false;
            } catch (ArtifactNotFoundException ex) {
                return false;
            }

        }

        /*
         * Resolves transitive dependencies.
         */
        private boolean resolveDependencies(org.apache.tuscany.spi.services.artifact.Artifact rootArtifact,
                                            org.apache.maven.artifact.Artifact mavenRootArtifact) {

            try {

                ResolutionGroup resolutionGroup = null;
                ArtifactResolutionResult result = null;

                resolutionGroup = metadataSource.retrieve(mavenRootArtifact, localRepository, remoteRepositories);
                result =
                    resolver.resolveTransitively(resolutionGroup.getArtifacts(),
                                                 mavenRootArtifact,
                                                 remoteRepositories,
                                                 localRepository,
                                                 metadataSource);

                // Add the artifacts to the deployment unit
                for (Object obj : result.getArtifacts()) {
                    org.apache.maven.artifact.Artifact depArtifact = (org.apache.maven.artifact.Artifact)obj;
                    org.apache.tuscany.spi.services.artifact.Artifact artifact =
                        new org.apache.tuscany.spi.services.artifact.Artifact();
                    artifact.setName(depArtifact.getArtifactId());
                    artifact.setGroup(depArtifact.getGroupId());
                    artifact.setType(depArtifact.getType());
                    artifact.setClassifier(depArtifact.getClassifier());
                    artifact.setUrl(depArtifact.getFile().toURL());
                    artifact.setVersion(depArtifact.getVersion());
                    rootArtifact.addDependency(artifact);
                }

            } catch (ArtifactMetadataRetrievalException ex) {
                return false;
            } catch (MalformedURLException ex) {
                throw new IllegalArgumentException(ex);
            } catch (ArtifactResolutionException ex) {
                return false;
            } catch (ArtifactNotFoundException ex) {
                return false;
            }

            return true;

        }

    }

    /**
     * @parameter
     */
    private URL systemScdl;

    /**
     * @parameter
     */
    private URL applicationScdl;

    /**
     * @parameter expression="${project.testClasspathElements}"
     * @required
     * @readonly
     */
    private List testClassPath;

    /**
     * Extensions
     * 
     * @parameter
     */
    private Dependency[] extensions = new Dependency[0];

    /**
     * Used to look up Artifacts in the remote repository.
     * 
     * @parameter expression="${component.org.apache.maven.artifact.resolver.ArtifactResolver}"
     * @required
     * @readonly
     */
    private ArtifactResolver resolver;

    /**
     * Used to look up Artifacts in the remote repository.
     * 
     * @parameter expression="${component.org.apache.maven.artifact.metadata.ArtifactMetadataSource}"
     * @required
     * @readonly
     */
    private ArtifactMetadataSource metadataSource;

    /**
     * Location of the local repository.
     * 
     * @parameter expression="${localRepository}"
     * @readonly
     * @required
     */
    private ArtifactRepository localRepository;

    /**
     * List of Remote Repositories used by the resolver
     * 
     * @parameter expression="${project.remoteArtifactRepositories}"
     * @readonly
     * @required
     */
    private List remoteRepositories;

    /**
     * Used to look up Artifacts in the remote repository.
     * 
     * @parameter expression="${component.org.apache.maven.artifact.factory.ArtifactFactory}"
     * @required
     * @readonly
     */
    private ArtifactFactory artifactFactory;

    static ThreadLocal<ClassLoader> foo = new ThreadLocal<ClassLoader>();

    public void execute() throws MojoExecutionException, MojoFailureException {
        getLog().info("Starting Tuscany...");

        ClassLoader hostClassLoader = getClass().getClassLoader();
        if (systemScdl == null) {
            systemScdl = hostClassLoader.getResource("META-INF/tuscany/embeddedMaven.scdl");
        }

        MavenRuntimeInfo runtimeInfo = new MavenRuntimeInfo();
        MavenEmbeddedRuntime runtime = new MavenEmbeddedRuntime();
        runtime.setArtifactRepository(new MavenEmbeddedArtifactRepository());

        for (Dependency d : extensions) {
            try {
                Artifact artifact = d.getArtifact(artifactFactory);
                resolver.resolve(artifact, remoteRepositories, localRepository);
                URL url = artifact.getFile().toURL();
                getLog().info(url.toString());
                runtime.addExtension(artifact.getGroupId() + ":" + artifact.getArtifactId(), url);
            } catch (Exception e) {
                throw new MojoExecutionException("Fail to resolve an extension", e);
            }
        }

        runtime.setSystemScdl(systemScdl);
        runtime.setHostClassLoader(hostClassLoader);

        ClassLoader applicationClassLoader = createApplicationClassLoader(hostClassLoader);
        if (applicationScdl == null) {
            Enumeration resources;
            try {
                resources = applicationClassLoader.getResources("META-INF/sca/default.scdl");
            } catch (IOException e) {
                throw new MojoExecutionException(e.getMessage(), e);
            }
            if (!resources.hasMoreElements()) {
                throw new MojoExecutionException("No SCDL found on test classpath");
            }
            applicationScdl = (URL)resources.nextElement();
            if (resources.hasMoreElements()) {
                StringBuffer msg = new StringBuffer();
                msg.append("Multiple SCDL files found on test classpath:\n");
                msg.append("  ").append(applicationScdl).append('\n');
                do {
                    msg.append("  ").append(resources.nextElement()).append('\n');
                } while (resources.hasMoreElements());
                throw new MojoExecutionException(msg.toString());
            }
        } else {
            if (applicationScdl.getProtocol() == null) {
                String resource = applicationScdl.getPath();
                applicationScdl = applicationClassLoader.getResource(resource);
                if (applicationScdl == null) {
                    throw new MojoExecutionException("Application SCDL cannot be resolved: " + resource);
                }
            }
        }
        runtime.setApplicationName("application");
        runtime.setApplicationScdl(applicationScdl);
        runtime.setApplicationClassLoader(applicationClassLoader);
        runtime.setRuntimeInfo(runtimeInfo);
        try {
            runtime.initialize();
        } catch (InitializationException e) {
            throw new MojoExecutionException("Error initializing", e);
        }
        CompositeContext context = runtime.getContext();
        CurrentCompositeContext.setContext(context);

        foo.set(applicationClassLoader);
    }

    public ClassLoader createApplicationClassLoader(ClassLoader parent) {
        URL[] urls = new URL[testClassPath.size()];
        int idx = 0;
        for (Iterator i = testClassPath.iterator(); i.hasNext();) {
            File pathElement = new File((String)i.next());
            try {
                URL url = pathElement.toURI().toURL();
                getLog().debug("Adding application URL: " + url);
                urls[idx++] = url;
            } catch (MalformedURLException e) {
                // toURI should have encoded the URL
                throw new AssertionError();
            }

        }
        return new URLClassLoader(urls, parent);
    }
}