/*
    * Copyright (c) 2006-present 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.codehaus.gmaven.plugin;
  
  import java.net.MalformedURLException;
  import java.net.URL;
  
  import javax.annotation.Nullable;
  
  import org.codehaus.gmaven.adapter.ResourceLoader;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  
  /**
   * Basic {@link ResourceLoader} implementation.
   *
   * @since 2.0
   */
  public class BasicResourceLoader
      implements ResourceLoader
  {
    protected static final String DOT_GROOVY = ".groovy";
  
    protected final Logger log = LoggerFactory.getLogger(getClass());
  
    protected final ClassLoader classLoader;
  
    public BasicResourceLoader(final ClassLoader classLoader) {
      this.classLoader = checkNotNull(classLoader);
    }
  
    @Nullable
    public URL loadResource(final String name) throws MalformedURLException {
      return resolve(name, classLoader);
    }
  
    @Nullable
    protected URL resolve(final String className, final ClassLoader classLoader) throws MalformedURLException {
      log.trace("Resolve; class-name: {}, class-loader: {}", className, classLoader);
  
      String name = resourceName(className);
  
      log.trace("Resolve; resource: {}", name);
  
      boolean tcl = false;
      URL resource = classLoader.getResource(name);
  
      // try from tcl if given CL does not resolve
      if (resource == null) {
        resource = Thread.currentThread().getContextClassLoader().getResource(name);
        tcl = true;
      }
  
      log.trace("Resource: {}, tcl: {}", resource, tcl);
  
      return resource;
    }
  
    /**
     * Translate class-name into resource-name.
     */
    protected String resourceName(final String className) {
      String name = className;
  
      if (!name.startsWith("/")) {
        name = "/" + name;
      }
  
      if (!name.endsWith(DOT_GROOVY)) {
        name = name.replace('.', '/');
        name += DOT_GROOVY;
      }
  
      return name;
    }
  }