/*
 * 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.geode.internal.logging.log4j;

import java.io.File;
import java.net.URL;

import org.apache.logging.log4j.core.util.Loader;
import org.apache.logging.log4j.util.LoaderUtil;

/**
 * Utility methods for finding the Log4J 2 configuration file.
 * 
 */
public class ConfigLocator {

  static final String PREFIX = "log4j2";

  static final String SUFFIX_TEST_YAML = "-test.yaml";
  static final String SUFFIX_TEST_YML = "-test.yml";
  static final String SUFFIX_TEST_JSON = "-test.json";
  static final String SUFFIX_TEST_JSN = "-test.jsn";
  static final String SUFFIX_TEST_XML = "-test.xml";
  static final String SUFFIX_YAML = ".yaml";
  static final String SUFFIX_YML = ".yml";
  static final String SUFFIX_JSON = ".json";
  static final String SUFFIX_JSN = ".jsn";
  static final String SUFFIX_XML = ".xml";

  /** Ordered as specified on http://logging.apache.org/log4j/2.x/manual/configuration.html */
  static final String[] SUFFIXES =
      new String[] {SUFFIX_TEST_YAML, SUFFIX_TEST_YML, SUFFIX_TEST_JSON, SUFFIX_TEST_JSN,
          SUFFIX_TEST_XML, SUFFIX_YAML, SUFFIX_YML, SUFFIX_JSON, SUFFIX_JSN, SUFFIX_XML};

  /**
   * Finds a Log4j configuration file in the current working directory. The names of the files to
   * look for are the same as those that Log4j would look for on the classpath.
   * 
   * @return configuration file or null if not found.
   */
  public static File findConfigInWorkingDirectory() {
    for (final String suffix : SUFFIXES) {
      final File configFile = new File(System.getProperty("user.dir"), PREFIX + suffix);
      if (configFile.isFile()) {
        return configFile;
      }
    }

    return null;
  }

  /**
   * This should replicate the classpath search for configuration file that Log4J 2 performs.
   * Returns the configuration location as URI or null if none is found.
   *
   * @return configuration location or null if not found
   */
  public static URL findConfigInClasspath() {
    final ClassLoader loader = LoaderUtil.getThreadContextClassLoader();
    for (final String suffix : SUFFIXES) {
      String resource = PREFIX + suffix;
      URL url = Loader.getResource(resource, loader);
      if (url != null) {
        // found it
        return url;
      }
    }
    return null;
  }
}