/*
    * Copyright (C) 2015 Uwe Plonus
    *
    * This program is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
    * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  package org.sw4j.apisniffer;
  
  import java.io.File;
  import java.io.FileFilter;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import javax.annotation.Nonnull;
  import javax.annotation.concurrent.NotThreadSafe;
  import org.objectweb.asm.ClassReader;
  import org.sw4j.apisniffer.api.Api;
  import org.sw4j.apisniffer.builder.ApiBuilder;
  import org.sw4j.apisniffer.visitor.ApiClassVisitor;
  
  /**
   *
   * @author Uwe Plonus &lt;u.plonus@gmail.com&gt;
   */
  @NotThreadSafe
  public class ApiScanner {
  
      private ApiBuilder apiBuilder;
  
      public void scanDirectory(@Nonnull final File folder) throws IOException {
          apiBuilder = new ApiBuilder();
          if (!folder.getAbsoluteFile().isDirectory()) {
              throw new IllegalArgumentException(
                  new StringBuilder("The method scanFolder(File) is for")
                      .append(" scanning folders. The provided file \"")
                      .append(folder.getAbsolutePath())
                      .append("\" is no folder.")
                      .toString());
          }
          File[] files = folder.getAbsoluteFile().listFiles(new DirectoryOrClassFileFilter());
          if (files != null) {
              for (File file: files) {
                  if (file.isDirectory()) {
                      scanDirectory(file);
                  } else {
                      scanClass(new FileInputStream(file));
                  }
              }
          }
      }
  
      private void scanClass(@Nonnull final InputStream classFile) throws IOException {
          ClassReader cr = new ClassReader(classFile);
          ApiClassVisitor cv = new ApiClassVisitor(apiBuilder);
          cr.accept(cv, 0);
      }
  
      public void scanJar(@Nonnull final InputStream is) throws IOException {
          apiBuilder = new ApiBuilder();
      }
  
      /**
       * Creates the API from the {@link #scanJar(java.io.InputStream) scanned jar file} or the
       * {@link #scanDirectory(java.io.File) scanned directory}.
       *
       * @return the API from the scanned files.
       */
      public Api createApi() {
          return null;
      }
  
  
      /**
       * A file filter to accept only directories or files with the suffix {@code .class}.
       */
      private static final class DirectoryOrClassFileFilter
      implements FileFilter {
  
          /**
           * Accepts only pathnames if it either is a directory or has the suffix {@code .class}.
           *
           * @param pathname the pathname to check.
           * @return {@code true} if the pathname is either a directory or a file with suffix
           *  {@code .class}.
           */
          @Override
          public boolean accept(final File pathname) {
              return pathname.isDirectory() ||
                  pathname.getName().endsWith(".class");
         }
 
     }
 
 }