/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2015 wcm.io
    * %%
    * 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.
   * #L%
   */
  package io.wcm.devops.conga.tooling.maven.plugin.util;
  
  import java.io.File;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.maven.artifact.DependencyResolutionRequiredException;
  import org.apache.maven.model.Resource;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.project.MavenProject;
  
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  import io.wcm.devops.conga.generator.spi.context.PluginContextOptions;
  import io.wcm.devops.conga.generator.spi.context.ValueProviderGlobalContext;
  import io.wcm.devops.conga.generator.util.VariableMapResolver;
  import io.wcm.devops.conga.generator.util.VariableStringResolver;
  
  /**
   * Utility methods for managing classpath and class loaders.
   */
  public final class ClassLoaderUtil {
  
    private ClassLoaderUtil() {
      // static methods only
    }
  
    /**
     * Build {@link ClassLoader} based on given list of dependency URLs.
     * @param classpathUrls Classpath urls
     * @return Resource loader
     */
    @SuppressFBWarnings("DP_CREATE_CLASSLOADER_INSIDE_DO_PRIVILEGED")
    public static ClassLoader buildClassLoader(List<URL> classpathUrls) {
      return new URLClassLoader(classpathUrls.toArray(new URL[0]));
    }
  
    /**
     * Build class loader from dependency of a maven project.
     * @param project Maven project
     * @return Class loader
     * @throws MojoExecutionException Mojo execution exception
     */
    public static List<URL> getMavenProjectClasspathUrls(MavenProject project) throws MojoExecutionException {
      try {
        List<URL> classpathUrls = new ArrayList<>();
        for (String path : project.getCompileClasspathElements()) {
          classpathUrls.add(new File(path).toURI().toURL());
        }
        for (Resource resource : project.getResources()) {
          classpathUrls.add(new File(resource.getDirectory()).toURI().toURL());
        }
        return classpathUrls;
      }
      catch (MalformedURLException | DependencyResolutionRequiredException ex) {
        throw new MojoExecutionException("Unable to get classpath elements for class loader.", ex);
      }
    }
  
    /**
     * Resolves an environment dependency URL.
     * @param dependencyUrl Dependeny URL
     * @param pluginContextOptions Plugin context options
     * @return Resolved dependency URL.
     */
    public static String resolveDependencyUrl(String dependencyUrl, PluginContextOptions pluginContextOptions) {
  
      ValueProviderGlobalContext valueProviderGlobalContext = new ValueProviderGlobalContext()
          .pluginContextOptions(pluginContextOptions);
      VariableMapResolver variableMapResolver = new VariableMapResolver(valueProviderGlobalContext);
      VariableStringResolver variableStringResolver = new VariableStringResolver(valueProviderGlobalContext, variableMapResolver);
  
      // resolver variables without config map - thus supporting only value providers with external values
      return variableStringResolver.resolveString(dependencyUrl, Map.of());
    }
  
  }