/*
 * Copyright 2008 Google Inc.
 * 
 * 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 com.google.gwt.dev;

import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.dev.javac.CompilationProblemReporter;
import com.google.gwt.dev.shell.log.SwingLoggerPanel;
import com.google.gwt.dev.util.log.PrintWriterTreeLogger;

/**
 * Used to run compiler tasks with the appropriate logger.
 */
public class CompileTaskRunner {

  /**
   * A task to run with a logger based on options.
   */
  public interface CompileTask {
    boolean run(TreeLogger logger) throws UnableToCompleteException;
  }

  /**
   * Runs the main action with an appropriate logger. If a gui-based TreeLogger
   * is used, this method will not return until its window is closed by the
   * user.
   */
  public static boolean runWithAppropriateLogger(CompileTaskOptions options,
      final CompileTask task) {
    // Set any platform specific system properties.
    BootStrapPlatform.applyPlatformHacks();

    // TODO(jat): add support for GUI logger back
    if (false && options.isUseGuiLogger()) {
      // Initialize a tree logger window.
      SwingLoggerPanel loggerWindow = new SwingLoggerPanel(
          options.getLogLevel(), null);

      // Eager AWT initialization for OS X to ensure safe coexistence with SWT.
      BootStrapPlatform.initGui();

      final TreeLogger logger = loggerWindow.getLogger();
      final boolean[] success = new boolean[1];

      // Compiler will be spawned onto a second thread, UI thread for tree
      // logger will remain on the main.
      Thread compilerThread = new Thread(new Runnable() {
        public void run() {
          success[0] = doRun(logger, task);
        }
      });

      compilerThread.setName("GWTCompiler Thread");
      compilerThread.start();
      // TODO(jat): create an app frame for loggerWindow
      
      // Even if the tree logger window is closed, we wait for the compiler
      // to finish.
      waitForThreadToTerminate(compilerThread);

      return success[0];
    } else {
      // Compile tasks without -treeLogger should run headless.
      if (System.getProperty("java.awt.headless") == null) {
        System.setProperty("java.awt.headless", "true");
      }
      PrintWriterTreeLogger logger = new PrintWriterTreeLogger();
      logger.setMaxDetail(options.getLogLevel());
      return doRun(logger, task);
    }
  }

  private static boolean doRun(TreeLogger logger, CompileTask task) {
    try {
      return task.run(logger);
    } catch (UnableToCompleteException e) {
      // Assume logged.
    } catch (Throwable e) {
      CompilationProblemReporter.logAndTranslateException(logger, e);
    }
    return false;
  }

  /**
   * Waits for a thread to terminate before it returns. This method is a
   * non-cancellable task, in that it will defer thread interruption until it is
   * done.
   * 
   * @param godot the thread that is being waited on.
   */
  private static void waitForThreadToTerminate(final Thread godot) {
    // Goetz pattern for non-cancellable tasks.
    // http://www-128.ibm.com/developerworks/java/library/j-jtp05236.html
    boolean isInterrupted = false;
    try {
      while (true) {
        try {
          godot.join();
          return;
        } catch (InterruptedException e) {
          isInterrupted = true;
        }
      }
    } finally {
      if (isInterrupted) {
        Thread.currentThread().interrupt();
      }
    }
  }
}