/*
 *  RightHandSide.java - transducer class
 *
 *  Copyright (c) 1998-2001, The University of Sheffield.
 *
 *  This file is part of GATE (see http://gate.ac.uk/), and is free
 *  software, licenced under the GNU Library General Public License,
 *  Version 2, June 1991 (in the distribution as file licence.html,
 *  and also available at http://gate.ac.uk/gate/licence.html).
 *
 *  Hamish Cunningham, 24/07/98
 *
 *  $Id$
 */


package ca.umontreal.iro.rali.gate.jape;

import java.util.*;
import java.io.*;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;


import gate.annotation.*;
import gate.util.*;
import gate.creole.ontology.Ontology;
import gate.*;


/**
  * The RHS of a CPSL rule. The action part. Contains an inner class
  * created from the code in the grammar RHS.
  */
public class RightHandSide implements JapeConstants, java.io.Serializable
{
  /** Debug flag */
  private static final boolean DEBUG = false;

  /** An instance of theActionClass. */
  transient private Object theActionObject;

  /** The string we use to create the action class. */
  private StringBuffer actionClassString;

  /** The bytes of the compiled action class. */
  private byte[] actionClassBytes;

  /** The name of the action class. */
  private String actionClassName;

  /** Package name for action classes. It's called a "dir name" because
    * we used to dump the action classes to disk and compile them there.
    */
  static private String actionsDirName = "japeactionclasses";

  /** The qualified name of the action class. */
  private String actionClassQualifiedName;

  /** Name of the .java file for the action class. */
  private String actionClassJavaFileName;

  /** Name of the .class file for the action class. */
  private String actionClassClassFileName;

  /** Cardinality of the action class set. Used for ensuring class name
    * uniqueness.
    */
  private static int actionClassNumber = 0;

  /** Allow setting of the initial action class number. Used for ensuring
    * class name uniqueness when running more than one transducer. The
    * long-term solution is to have separate class loaders for each
    * transducer.
    */
  public static void setActionClassNumber(int n) { actionClassNumber = n; }

  /** The set of block names.
    * Used to ensure we only get their annotations once in the action class.
    */
  private HashSet blockNames;

  /** Returns the string for the java code */
  public String getActionClassString() { return actionClassString.toString(); }

  public String getActionClassName() { return actionClassQualifiedName; }

  /** The LHS of our rule, where we get bindings from. */
  private LeftHandSide lhs;

  /** A list of the files and directories we create. */
  static private ArrayList tempFiles = new ArrayList();

  /** Local fashion for newlines. */
  private final String nl = Strings.getNl();

  /** Debug flag. */
  static final boolean debug = false;
  private String phaseName;
  private String ruleName;

  /** Construction from the transducer name, rule name and the LHS. */
  public RightHandSide(
    String transducerName, String ruleName, LeftHandSide lhs
  ) {
    // debug = true;
    this.lhs = lhs;
    this.phaseName = transducerName;
    this.ruleName = ruleName;
    actionClassName = new String(
      transducerName + ruleName + "ActionClass" + actionClassNumber++
    );
    blockNames = new HashSet();

    // initialise the class action string
    actionClassString = new StringBuffer(
      "// " + actionClassName + nl +
      "package " + actionsDirName + "; " + nl +
      "import java.io.*;" + nl +
      "import java.util.*;" + nl +
      "import gate.*;" + nl +
      "import ca.umontreal.iro.rali.gate.jape.*;" + nl +
      "import gate.creole.ontology.Ontology;" + nl +
      "import gate.annotation.*;" + nl +
      "import gate.util.*;" + nl + nl +
      "public class " + actionClassName + nl +
      "implements java.io.Serializable, RhsAction { " + nl +
      "  public void doit(Document doc, java.util.Map bindings, " + nl +
      "                   AnnotationSet annotations, " + nl +
      "                   AnnotationSet inputAS, AnnotationSet outputAS, " + nl +
      "                   Ontology ontology) {" + nl
    );

    // initialise various names
    actionClassJavaFileName =
      actionsDirName +  File.separator +
      actionClassName.replace('.', File.separatorChar) + ".java";
    actionClassQualifiedName =
      actionsDirName.
      replace(File.separatorChar, '.').replace('/', '.').replace('\\', '.') +
      "." + actionClassName;
    actionClassClassFileName =
      actionClassQualifiedName.replace('.', File.separatorChar) + ".class";
  } // Construction from lhs

  /** Add an anonymous block to the action class */
  public void addBlock(String anonymousBlock) {
    actionClassString.append(anonymousBlock);
    actionClassString.append(nl);
  } // addBlock(anon)

  /** Add a named block to the action class */
  public void addBlock(String name, String namedBlock) {
    // is it really a named block?
    // (dealing with null name cuts code in the parser...)
    if(name == null) {
      addBlock(namedBlock);
      return;
    }

    if(blockNames.add(name)) // it wasn't already a member
      actionClassString.append(
        "    AnnotationSet " + name + "Annots = (AnnotationSet)bindings.get(\""
        + name + "\"); " + nl
      );

    actionClassString.append(
      "    if(" + name + "Annots != null && " + name +
      "Annots.size() != 0) { " + nl + "      " + namedBlock +
      nl + "    }" + nl
    );
  } // addBlock(name, block)

  /** Create the action class and an instance of it. */
  public void createActionClass() throws JapeException {
    // terminate the class string
    actionClassString.append("  }" + nl + "}" + nl);
//    try {
//      Javac.loadClass(actionClassString.toString(),
//                           actionClassJavaFileName);
//    } catch(GateException e) {
//      String nl = Strings.getNl();
//      String actionWithNumbers =
//        Strings.addLineNumbers(actionClassString.toString());
//      throw new JapeException(
//        "Couldn't create action class: " + nl + e + nl +
//        "offending code was: " + nl + actionWithNumbers + nl
//      );
//    }
//    instantiateActionClass();
  } // createActionClass

  /** Create an instance of the action class. */
  public void instantiateActionClass() throws JapeException {

    try {
      theActionObject = Gate.getClassLoader().
                        loadClass(actionClassQualifiedName).
                        newInstance();
    } catch(Exception e) {
      throw new JapeException(
        "couldn't create instance of action class " + actionClassName + ": "
        + e.getMessage()
      );
    }
  } // instantiateActionClass

  /** Remove class files created for actions. */
  public static void cleanUp() {
    if(tempFiles.size() == 0) return;

    // traverse the list in reverse order, coz any directories we
    // created were done first
    for(ListIterator i = tempFiles.listIterator(tempFiles.size()-1);
        i.hasPrevious();
       ) {
      File tempFile = (File) i.previous();
      tempFile.delete();
    } // for each tempFile

    tempFiles.clear();
  } // cleanUp


  /** Makes changes to the document, using LHS bindings. */
  public void transduce(Document doc, java.util.Map bindings,
                        AnnotationSet inputAS, AnnotationSet outputAS,
                        Ontology ontology)
                        throws JapeException {
    if(theActionObject == null) {
      instantiateActionClass();
    }

    // run the action class
    try {
      ((RhsAction) theActionObject).doit(doc, bindings, outputAS,
                                         inputAS, outputAS, ontology);

    // if the action class throws an exception, re-throw it with a
    // full description of the problem, inc. stack trace and the RHS
    // action class code
    } catch (Exception e) {
      StringWriter stackTraceWriter = new StringWriter();
      e.printStackTrace(new PrintWriter(stackTraceWriter));
      throw new JapeException(
        "Couldn't run RHS action: " + Strings.getNl() +
        stackTraceWriter.getBuffer().toString() +
        Strings.addLineNumbers(actionClassString.toString())
      );
    }
  } // transduce

  /** Create a string representation of the object. */
  public String toString() { return toString(""); }

  /** Create a string representation of the object. */
  public String toString(String pad) {
    String nl = Strings.getNl();
    StringBuffer buf = new StringBuffer(
      pad + "RHS: actionClassName(" + actionClassName + "); "
    );
    //buf.append("actionClassString(" + nl + actionClassString + nl);
    buf.append(
      "actionClassClassFileName(" + nl + actionClassClassFileName + nl
    );
    buf.append("actionClassJavaFileName(" + nl + actionClassJavaFileName + nl);
    buf.append(
      "actionClassQualifiedName(" + nl + actionClassQualifiedName + nl
    );

    buf.append("blockNames(" + blockNames.toString() + "); ");

    buf.append(nl + pad + ") RHS." + nl);

    return buf.toString();
  } // toString

  /** Create a string representation of the object. */
  public String shortDesc() {
    String res = "" + actionClassName;
    return res;
  }
  public void setPhaseName(String phaseName) {
    this.phaseName = phaseName;
  }
  public String getPhaseName() {
    return phaseName;
  }
  public void setRuleName(String ruleName) {
    this.ruleName = ruleName;
  }
  public String getRuleName() {
    return ruleName;
  } // toString

} // class RightHandSide