/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
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 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
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 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
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 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
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 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.tools.ant.taskdefs.optional;

import org.apache.tools.ant.*;
import java.io.*;
import java.util.*;
import com.ibm.bsf.*;

/**
 * Execute a script
 *
 * @author Sam Ruby <a href="mailto:rubys@us.ibm.com">rubys@us.ibm.com</a>
 */
public class Script extends Task {
    private String language;
    private String registerlanguage;
    private String registerclass;
    private String registerextra;
    private String script = "";
    private Hashtable beans = new Hashtable();
    
    /**
     * Add a list of named objects to the list to be exported to the script
     */
    private void addBeans(Hashtable dictionary) {
        for (Enumeration e=dictionary.keys(); e.hasMoreElements(); ) {
            String key = (String)e.nextElement();

	    boolean isValid = key.length()>0 &&
                Character.isJavaIdentifierStart(key.charAt(0));

            for (int i=1; isValid && i<key.length(); i++)
                isValid = Character.isJavaIdentifierPart(key.charAt(i));

            if (isValid) beans.put(key, dictionary.get(key));
        }
    }

    /**
     * Do the work.
     *
     * @exception BuildException if someting goes wrong with the build
     */
    public void execute() throws BuildException {
        if ( language == null &&
	        ( registerlanguage == null ||
                registerclass == null ||
                registerextra == null ) ) {
            throw new BuildException("script: must supply either language or register attributes");
        }
        try {
            if ( language == null ) {
                BSFManager.registerScriptingEngine(registerlanguage,
                    registerclass, new String[]{registerextra});
                return;
            }
	        
            addBeans(project.getProperties());
            addBeans(project.getUserProperties());
            addBeans(project.getTargets());
            addBeans(project.getReferences());

            BSFManager manager = new BSFManager ();
            manager.loadScriptingEngine(language);

            for (Enumeration e = beans.keys() ; e.hasMoreElements() ;) {
                String key = (String)e.nextElement();
                Object value = beans.get(key);
                manager.declareBean(key, value, value.getClass());
            }

            // execute the script
            manager.exec(language, "<ANT>", 0, 0, script);
        } catch (BSFException be) {
	    Exception e = be;
            Throwable te = be.getTargetException();
            if (te != null && te instanceof Exception) e = (Exception) te;
            throw new BuildException(e);
        }
    }

    /**
     * Defines the language
     *
     * @param msg Sets the value for the script variable.
     */
    public void setLanguage(String language) {
	this.language = language;
    }

    /**
     * Defines the language to be registered.
     *
     * @param msg Sets the value for the script variable.
     */
    public void setRegisterlanguage(String registerlanguage) {
	this.registerlanguage = registerlanguage;
    }

    /**
     * Defines the class to be registered.
     *
     * @param msg Sets the value for the script variable.
     */
    public void setRegisterclass(String registerclass) {
	this.registerclass = registerclass;
    }

    /**
     * Defines the extra text to be registered.
     *
     * @param msg Sets the value for the script variable.
     */
    public void setRegisterextra(String registerextra) {
	this.registerextra = registerextra;
    }

    /**
     * Load the script from an external file 
     *
     * @param msg Sets the value for the script variable.
     */
    public void setSrc(String fileName) {
        File file = new File(fileName);
        if (!file.exists()) 
            throw new BuildException("file " + fileName + " not found.");

        int count = (int)file.length();
        byte data[] = new byte[count];

        try {
            FileInputStream inStream = new FileInputStream(file);
            inStream.read(data);
            inStream.close();
        } catch (IOException e) {
            throw new BuildException(e);
        }
	
        script += new String(data);
    }

    /**
     * Defines the script.
     *
     * @param msg Sets the value for the script variable.
     */
    public void addText(String text) {
	this.script += text;
    }
}