/*
    Dateiverwaltung - File management in your browser
    Copyright (C) 2017 Ulrich Hilger, http://uhilger.de

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero 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 Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
package de.uhilger.filecms.api;

import static de.uhilger.filecms.api.FileMgr.HOME_DIR_NAME;
import static de.uhilger.filecms.api.FileMgr.HOME_DIR_PATH;
import static de.uhilger.filecms.api.FileMgr.PUB_DIR_NAME;
import static de.uhilger.filecms.api.FileMgr.PUB_DIR_PATH;
import de.uhilger.filecms.data.FileRef;
import de.uhilger.filecms.web.Initialiser;
import de.uhilger.transit.web.RequestKontext;
import de.uhilger.transit.web.WebKontext;
import java.io.File;
import java.io.IOException;
import java.security.Principal;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.logging.Logger;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.tools.Diagnostic;
import javax.tools.DiagnosticCollector;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;
import org.apache.commons.io.FileUtils;

/**
 *
 */
public class CompileService implements RequestKontext, WebKontext {
  
  private static final Logger logger = Logger.getLogger(CompileService.class.getName());
  
  private ServletContext ctx;
  private HttpServletRequest request;
  
  public String compile(String relPath, List fileNames) throws IOException {
    //Files[] files1 = ... ; // input for first compilation task
    //Files[] files2 = ... ; // input for second compilation task
    
    File targetDir = getTargetDir(relPath);
    //System.out.println(targetDir.getAbsolutePath());
    ArrayList<File> files = new ArrayList();
    
    for(int i=0; i < fileNames.size(); i++) {
      Object o = fileNames.get(i);
      if(o instanceof ArrayList) {
        ArrayList al = (ArrayList) o;
        logger.fine(al.get(0).toString());
        File targetFile = new File(targetDir, al.get(0).toString());
        logger.fine(targetFile.getAbsolutePath());
        files.add(targetFile);
      }
    }

    JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
    DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector();
    StandardJavaFileManager fileManager = compiler.getStandardFileManager(diagnostics, null, null);

    Iterable<? extends JavaFileObject> compilationUnits1 = fileManager.getJavaFileObjectsFromFiles(files);
    
    final Iterable<String> options =
            Arrays.asList(new String[]{"-Xlint",
              /*"-cp", project.getClassPath(),*/
              "-d", targetDir.getAbsolutePath()
              });
    
    compiler.getTask(null, fileManager, diagnostics, options, null, compilationUnits1).call();

    /*
    Iterable<? extends JavaFileObject> compilationUnits2
            = fileManager.getJavaFileObjects(files2); // use alternative method
    // reuse the same file manager to allow caching of jar files
    compiler.getTask(null, fileManager, null, null, null, compilationUnits2).call();
    */
    fileManager.close();

    StringBuilder msg = new StringBuilder();
    msg.append("Result of compile to Java bytecode (empty means no error):");
    for (Diagnostic<? extends JavaFileObject> err : diagnostics.getDiagnostics()) {
      msg.append('\n');
      msg.append(err.getKind());
      msg.append(": ");
      if (err.getSource() != null) {
        msg.append(err.getSource().getName());
      }
      msg.append(':');
      msg.append(err.getLineNumber());
      msg.append(": ");
      msg.append(err.getMessage(Locale.GERMANY));
    }    
    
    return msg.toString();
  }
  private File getTargetDir(String relPath) {
    logger.fine(relPath);
    String targetPath = null;
    if(relPath.startsWith(PUB_DIR_NAME)) {
      targetPath = PUB_DIR_PATH + getUserName() + relPath.substring(PUB_DIR_NAME.length());
    } else if(relPath.startsWith(HOME_DIR_NAME)) {
      targetPath = HOME_DIR_PATH + getUserName() + relPath.substring(HOME_DIR_NAME.length());
    } else {
      // kann eigentlich nicht sein..
    }
    logger.fine(targetPath);
    File targetDir = new File(getBase().getAbsolutePath(), targetPath);
    return targetDir;
  }
  
  private FileRef getBase() {
    FileRef base = null;
    Object o = getServletContext().getAttribute(Initialiser.FILE_BASE);
    if(o instanceof String) {
      String baseStr = (String) o;
      logger.fine(baseStr);
      File file = new File(baseStr);
      base = new FileRef(file.getAbsolutePath(), file.isDirectory());
    }
    return base;
  }
  private String getUserName() {
    String userName = null;
    Object p = getRequest().getUserPrincipal();
    if(p instanceof Principal) {
      userName = ((Principal) p).getName();
    }
    return userName;
  }    

  @Override
  public HttpServletRequest getRequest() {
    return request;
  }

  @Override
  public void setRequest(HttpServletRequest r) {
    this.request = r;
  }

  @Override
  public ServletContext getServletContext() {
    return ctx;
  }

  @Override
  public void setServletContext(ServletContext servletContext) {
    this.ctx = servletContext;
  }
}


/*

 Beispeil fuer einen dynamischen Compiler-Aufruf
 'in memory'

 String className = "mypackage.MyClass";
 String javaCode = "package mypackage;\n" +
                  "public class MyClass implements Runnable {\n" +
                  "    public void run() {\n" +
                  "        System.out.println("\"Hello World\");\n" +
                  "    }\n" +
                  "}\n";
 Class aClass = CompilerUtils.CACHED_COMPILER.loadFromJava(className, javaCode);
 Runnable runner = (Runnable) aClass.newInstance();
 runner.run();

*/