package pt.ist.fenixframework.dml.maven;

// import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
// import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.codehaus.classworlds.ClassRealm;
import org.codehaus.plexus.component.configurator.AbstractComponentConfigurator;
import org.codehaus.plexus.component.configurator.ComponentConfigurationException;
import org.codehaus.plexus.component.configurator.ConfigurationListener;
import org.codehaus.plexus.component.configurator.converters.composite.ObjectWithFieldsConverter;
import org.codehaus.plexus.component.configurator.converters.special.ClassRealmConverter;
import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluationException;
import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluator;
import org.codehaus.plexus.configuration.PlexusConfiguration;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

// IMPORTANT: THE FOLLOWING MUST BE A JAVADOC-STYLE COMMENT.  IT IS NECESSARY FOR THE CORRECT
// OPERATION OF THIS PLUGIN
/**
 * A custom ComponentConfigurator which adds the project's runtime classpath elements to the plugin
 *
 * @author Brian Jackson
 * @since Aug 1, 2008 3:04:17 PM
 *
 * @plexus.component role="org.codehaus.plexus.component.configurator.ComponentConfigurator"
 *                   role-hint="include-project-dependencies"
 * @plexus.requirement role="org.codehaus.plexus.component.configurator.converters.lookup.ConverterLookup"
 *                   role-hint="default"
 *
 * From: http://stackoverflow.com/questions/2659048/add-maven-build-classpath-to-plugin-execution-classpath
 */
public class IncludeProjectDependenciesComponentConfigurator extends AbstractComponentConfigurator { 

    // private static final Logger LOGGER = LoggerFactory.getLogger(IncludeProjectDependenciesComponentConfigurator.class);

    public void configureComponent( Object component, PlexusConfiguration configuration,
                                    ExpressionEvaluator expressionEvaluator, ClassRealm containerRealm,
                                    ConfigurationListener listener )
        throws ComponentConfigurationException {

        addProjectDependenciesToClassRealm(expressionEvaluator, containerRealm);

        converterLookup.registerConverter( new ClassRealmConverter( containerRealm ) );

        ObjectWithFieldsConverter converter = new ObjectWithFieldsConverter();

        converter.processConfiguration( converterLookup, component, containerRealm.getClassLoader(), configuration,
                                        expressionEvaluator, listener );
    }

    private void addProjectDependenciesToClassRealm(ExpressionEvaluator expressionEvaluator, ClassRealm containerRealm) throws ComponentConfigurationException {
        List<String> runtimeClasspathElements;
        try {
            //noinspection unchecked
            runtimeClasspathElements = (List<String>) expressionEvaluator.evaluate("${project.runtimeClasspathElements}");
        } catch (ExpressionEvaluationException e) {
            throw new ComponentConfigurationException("There was a problem evaluating: ${project.runtimeClasspathElements}", e);
        }

        // Add the project dependencies to the ClassRealm
        final URL[] urls = buildURLs(runtimeClasspathElements);
        for (URL url : urls) {
            containerRealm.addConstituent(url);
        }
    }

    private URL[] buildURLs(List<String> runtimeClasspathElements) throws ComponentConfigurationException {
        // Add the projects classes and dependencies
        List<URL> urls = new ArrayList<URL>(runtimeClasspathElements.size());
        for (String element : runtimeClasspathElements) {
            try {
                final URL url = new File(element).toURI().toURL();
                urls.add(url);
                // if (LOGGER.isDebugEnabled()) {
                //     LOGGER.debug("Added to project class loader: " + url);
                // }
            } catch (MalformedURLException e) {
                throw new ComponentConfigurationException("Unable to access project dependency: " + element, e);
            }
        }

        // Add the plugin's dependencies (so Trove stuff works if Trove isn't on
        return urls.toArray(new URL[urls.size()]);
    }

}