/*
    * Copyright 2014 The Netty Project
    *
    * The Netty Project 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.jboss.netty.util.internal;
  
  import org.jboss.netty.logging.InternalLogger;
  import org.jboss.netty.logging.InternalLoggerFactory;
  
  import java.io.File;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.net.URL;
  import java.util.Locale;
  
  /**
   * Helper class to load JNI resources.
   *
   */
  public final class NativeLibraryLoader {
  
      private static final InternalLogger logger = InternalLoggerFactory.getInstance(NativeLibraryLoader.class);
  
      private static final String NATIVE_RESOURCE_HOME = "META-INF/native/";
      private static final String OSNAME;
      private static final File WORKDIR;
  
      static {
          OSNAME = SystemPropertyUtil.get("os.name", "").toLowerCase(Locale.US).replaceAll("[^a-z0-9]+", "");
  
          String workdir = SystemPropertyUtil.get("io.netty.native.workdir");
          if (workdir != null) {
              File f = new File(workdir);
              if (!f.exists()) {
                  // ok to ignore as createTempFile will take care
                  //noinspection ResultOfMethodCallIgnored
                  f.mkdirs();
              }
  
              try {
                  f = f.getAbsoluteFile();
              } catch (Exception ignored) {
                  // Good to have an absolute path, but it's OK.
              }
  
              WORKDIR = f;
              logger.debug("-Dio.netty.netty.workdir: " + WORKDIR);
          } else {
              WORKDIR = tmpdir();
              logger.debug("-Dio.netty.netty.workdir: " + WORKDIR + " (io.netty.tmpdir)");
          }
      }
  
      private static File tmpdir() {
          File f;
          try {
              f = toDirectory(SystemPropertyUtil.get("io.netty.tmpdir"));
              if (f != null) {
                  logger.debug("-Dio.netty.tmpdir: " + f);
                  return f;
              }
  
              f = toDirectory(SystemPropertyUtil.get("java.io.tmpdir"));
              if (f != null) {
                  logger.debug("-Dio.netty.tmpdir: " + f + " (java.io.tmpdir)");
                  return f;
              }
  
              // This shouldn't happen, but just in case ..
              if (isWindows()) {
                  f = toDirectory(System.getenv("TEMP"));
                  if (f != null) {
                      logger.debug("-Dio.netty.tmpdir: " + f + " (%TEMP%)");
                      return f;
                  }
  
                  String userprofile = System.getenv("USERPROFILE");
                  if (userprofile != null) {
                      f = toDirectory(userprofile + "\\AppData\\Local\\Temp");
                      if (f != null) {
                          logger.debug("-Dio.netty.tmpdir: " + f + " (%USERPROFILE%\\AppData\\Local\\Temp)");
                          return f;
                      }
  
                      f = toDirectory(userprofile + "\\Local Settings\\Temp");
                     if (f != null) {
                         logger.debug("-Dio.netty.tmpdir: " + f + " (%USERPROFILE%\\Local Settings\\Temp)");
                         return f;
                     }
                 }
             } else {
                 f = toDirectory(System.getenv("TMPDIR"));
                 if (f != null) {
                     logger.debug("-Dio.netty.tmpdir: " + f + " ($TMPDIR)");
                     return f;
                 }
             }
         } catch (Exception ignored) {
             // Environment variable inaccessible
         }
 
         // Last resort.
         if (isWindows()) {
             f = new File("C:\\Windows\\Temp");
         } else {
             f = new File("/tmp");
         }
 
         logger.warn("Failed to get the temporary directory; falling back to: " + f);
         return f;
     }
 
     @SuppressWarnings("ResultOfMethodCallIgnored")
     private static File toDirectory(String path) {
         if (path == null) {
             return null;
         }
 
         File f = new File(path);
         if (!f.exists()) {
             f.mkdirs();
         }
 
         if (!f.isDirectory()) {
             return null;
         }
 
         try {
             return f.getAbsoluteFile();
         } catch (Exception ignored) {
             return f;
         }
     }
 
     private static boolean isWindows() {
         return OSNAME.startsWith("windows");
     }
 
     private static boolean isOSX() {
         return OSNAME.startsWith("macosx") || OSNAME.startsWith("osx");
     }
 
     /**
      * Load the given library with the specified {@link java.lang.ClassLoader}
      */
     public static void load(String name, ClassLoader loader) {
         String libname = System.mapLibraryName(name);
         String path = NATIVE_RESOURCE_HOME + libname;
 
         URL url = loader.getResource(path);
         if (url == null && isOSX()) {
             if (path.endsWith(".jnilib")) {
                 url = loader.getResource(NATIVE_RESOURCE_HOME + "lib" + name + ".dynlib");
             } else {
                 url = loader.getResource(NATIVE_RESOURCE_HOME + "lib" + name + ".jnilib");
             }
         }
 
         if (url == null) {
             // Fall back to normal loading of JNI stuff
             System.loadLibrary(name);
             return;
         }
 
         int index = libname.lastIndexOf('.');
         String prefix = libname.substring(0, index);
         String suffix = libname.substring(index, libname.length());
         InputStream in = null;
         OutputStream out = null;
         File tmpFile = null;
         boolean loaded = false;
         try {
             tmpFile = File.createTempFile(prefix, suffix, WORKDIR);
             in = url.openStream();
             out = new FileOutputStream(tmpFile);
 
             byte[] buffer = new byte[8192];
             int length;
             while ((length = in.read(buffer)) > 0) {
                 out.write(buffer, 0, length);
             }
             out.flush();
             out.close();
             out = null;
 
             System.load(tmpFile.getPath());
             loaded = true;
         } catch (Exception e) {
             throw (UnsatisfiedLinkError) new UnsatisfiedLinkError(
                     "could not load a native library: " + name).initCause(e);
         } finally {
             if (in != null) {
                 try {
                     in.close();
                 } catch (IOException ignore) {
                     // ignore
                 }
             }
             if (out != null) {
                 try {
                     out.close();
                 } catch (IOException ignore) {
                     // ignore
                 }
             }
             if (tmpFile != null) {
                 if (loaded) {
                     tmpFile.deleteOnExit();
                 } else {
                     if (!tmpFile.delete()) {
                         tmpFile.deleteOnExit();
                     }
                 }
             }
         }
     }
 
     private NativeLibraryLoader() {
         // Utility
     }
 }