/*
 * Copyright 2006 Ralf Jaochim
 *
 * 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.castor.xmlctf.compiler;

import java.io.File;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;

import org.castor.xmlctf.XMLTestCase;
import org.castor.xmlctf.util.FileServices;

/**
 * Compiles a directory tree, recursively. This class is built to use the Sun Javac compiler
 * contained in tools.jar. A IllegalStateException will be thrown if tools.jar is not on the
 * classpath at construction of the class and execution of the compileDirectory() method.
 *
 * @author <a href="mailto:ralf DOT joachim AT syscon DOT eu">Ralf Joachim</a>
 * @version $Revision: 5951 $ $Date: 2006-04-25 16:09:10 -0600 (Tue, 25 Apr 2006) $
 * @since 1.0.5
 */
public class SunJavaCompiler implements Compiler {

  private static final int COMPILATION_SUCCESS = 0;
  private static final int COMPILATION_ERROR = 1;
  private static final int COMPILATION_CMDERR = 2;
  private static final int COMPILATION_SYSERR = 3;
  private static final int COMPILATION_ABNORMAL = 4;

  private static final String COMPILE_CLASSNAME = "sun.tools.javac.Main";
  private static final String COMPILE_METHODNAME = "compile";
  private static final Class[] COMPILE_PARAMTYPE = new Class[] {String[].class};

  private static final HashSet IGNORE_DIRS = new HashSet();

  private static Method _compileMethod = null;
  private static boolean _initialized = false;
  /** Java version of the JVM we are running in. */
  private static final float JAVA_VERSION =
      Float.parseFloat(System.getProperty("java.specification.version"));

  private String _javaVersion = null;

  private final File _baseDirectory;
  private final File _outputDirectory;

  /**
   * Creates a compiler for a given directory.
   * 
   * @param baseDirectory The directory that holds the files to be compiled.
   */
  public SunJavaCompiler(final File baseDirectory) {
    if (baseDirectory == null) {
      throw new IllegalArgumentException("'baseDirectory' must not be null.");
    }
    _baseDirectory = baseDirectory;
    _outputDirectory = baseDirectory;

    if (!_initialized) {
      initialize();
    }
  }

  /**
   * Sets the Java source version the current test will be using.
   * 
   * @param javaSourceVersion The Java Source version to be used.
   */
  public void setJavaSourceVersion(final float javaSourceVersion) {
    float srcVersion = javaSourceVersion;
    if (javaSourceVersion >= 5F && javaSourceVersion < 10F) {
      srcVersion = 1.0F + (javaSourceVersion / 10F);
    }
    _javaVersion = "" + srcVersion;
  }

  /**
   * Initialize.
   */
  private void initialize() {
    IGNORE_DIRS.add(FileServices.CVS);
    IGNORE_DIRS.add(FileServices.SVN);

    try {
      ClassLoader loader = this.getClass().getClassLoader();
      Class cls = loader.loadClass(COMPILE_CLASSNAME);
      _compileMethod = cls.getMethod(COMPILE_METHODNAME, COMPILE_PARAMTYPE);
    } catch (Exception ex) {
      IllegalStateException ise = new IllegalStateException("Failed to find compile method.");
      ise.initCause(ex);
      throw ise;
    }

    _initialized = true;
  }

  /**
   * Compiles the content of a directory. Throws a <code>CompilationException</code> if the build
   * fails.
   */
  public void compileDirectory() {
    List filesList = findSourceFiles(_baseDirectory);
    if (filesList.size() > 0) {
      filesList.addAll(0, getCompileArguments(_baseDirectory, _outputDirectory));

      String[] args = new String[filesList.size()];
      args = (String[]) filesList.toArray(args);

      int status;
      try {
        Object result = _compileMethod.invoke(null, new Object[] {args});
        status = ((Integer) result).intValue();
      } catch (Exception ex) {
        throw new IllegalStateException("Failed to call compile method.");
      }

      switch (status) {
        case COMPILATION_SUCCESS:
          break;
        case COMPILATION_ERROR:
          throw new CompilationException("Compile status: ERROR");
        case COMPILATION_CMDERR:
          throw new CompilationException("Compile status: CMDERR");
        case COMPILATION_SYSERR:
          throw new CompilationException("Compile status: SYSERR");
        case COMPILATION_ABNORMAL:
          throw new CompilationException("Compile status: ABNORMAL");
        default:
          throw new CompilationException("Compile status: Unknown");
      }
    } else {
      throw new CompilationException("No files to compile: " + _baseDirectory);
    }
  }

  /**
   * Returns a list of arguments for the compiler.
   * 
   * @param srcDir The source directory for compilation
   * @param destDir The destination directory for compilation
   * @return a list of arguments for the compiler.
   */
  private List getCompileArguments(final File srcDir, final File destDir) {
    List args = new ArrayList();

    args.add("-g");
    if (JAVA_VERSION == 1.5F) {
      args.add("-Xlint:unchecked");
    }
    if (XMLTestCase._verbose) {
      args.add("-verbose");
    } else {
      args.add("-nowarn");
      args.add("-Xmaxwarns");
      args.add("0");
      args.add("-Xmaxerrs");
      args.add("5");
    }
    if (_javaVersion != null) {
      args.add("-source");
      args.add(_javaVersion);
    }
    args.add("-classpath");
    String classPathOverriden = System.getProperty("xmlctf.classpath.override");
    if (classPathOverriden != null) {
      args.add(classPathOverriden + ";" + destDir.getAbsolutePath());
    } else {
      args.add(System.getProperty("java.class.path") + ";" + destDir.getAbsolutePath());
    }
    args.add("-d");
    args.add(destDir.getAbsolutePath());
    args.add("-sourcepath");
    args.add(srcDir.getAbsolutePath());
    return args;
  }

  /**
   * Recursively searches the provided directory, returning a list of all Java files found.
   * 
   * @param srcDir A directory to search for Java files.
   * @return a List of all Java files found in the provided directory
   */
  private List findSourceFiles(final File srcDir) {
    List files = new ArrayList();

    File[] entries = srcDir.listFiles();
    for (int i = 0; i < entries.length; i++) {
      File entry = entries[i];
      if (entry.getName().endsWith(".java")) {
        files.add(entry.getAbsolutePath());
      } else if (entry.isDirectory() && !IGNORE_DIRS.contains(entry.getName())) {
        files.addAll(findSourceFiles(entry));
      }
    }

    return files;
  }

}
