package cn.home1.cloud.config.server.util;
   
   import static com.google.common.base.Preconditions.checkArgument;
   import static lombok.AccessLevel.PRIVATE;
   import static org.apache.commons.io.FileUtils.copyInputStreamToFile;
   import static org.apache.commons.io.FileUtils.forceMkdir;
   
   import cn.home1.cloud.config.server.ConfigServer;
   
  import lombok.NoArgsConstructor;
  import lombok.SneakyThrows;
  
  import org.apache.commons.lang3.StringUtils;
  
  import java.io.File;
  import java.io.InputStream;
  
  @NoArgsConstructor(access = PRIVATE)
  public abstract class ResourceUtils {
  
      /**
       * Find resource in classpath and on filesystem, return its path or null (not found)
       *
       * @param location        start with 'classpath:' or 'file:'
       * @param outputDirectory dump resource into 'outputDirectory + location', if found in classpath
       * @return resource file path or null (not found)
       */
      @SneakyThrows
      public static String findResourceFile(final String location, final String outputDirectory) {
          final String result;
  
          if (location.startsWith("classpath:")) {
              // see: http://www.baeldung.com/convert-input-stream-to-a-file
              // read resource from classpath
              final String fileName = StringUtils.replaceOnce(location, "classpath:", "");
              final InputStream streamIn = ConfigServer.class.getClassLoader().getResourceAsStream(fileName);
              checkArgument(streamIn != null,
                  "resource '" + location + "' not found in classpath ('" + fileName + "')");
  
              // write resource to filesystem
              forceMkdir(new File(outputDirectory));
              final File fileOut = new File(outputDirectory + (location.startsWith("/") ? location : "/" + location));
              copyInputStreamToFile(streamIn, fileOut);
              checkArgument(fileOut.exists() && fileOut.canRead(),
                  "File '" + fileOut.getPath() + "' not found or not readable");
  
              result = fileOut.getPath();
          } else if (location.startsWith("file:")) {
              result = StringUtils.replaceOnce(location, "file:", "");
          } else {
              result = location;
          }
  
          return result;
      }
  }