/*
 This file is part of the software framework JStatCom, 
 a library for building applications for data based analysis.

 Copyright (C) 2000-2005  Markus Kraetzig

 This library is free software; you can redistribute it and/or modify
 it under the terms of the GNU Lesser General Public License as
 published by the Free Software Foundation; either version 2.1 of the
 License, or (at your option) any later version.

 This library 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
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 USA
 */

package com.jstatcom.engine.gauss;

import java.io.File;
import java.io.IOException;
import java.util.Map;

import com.jstatcom.engine.AbstractConfigPanel;
import com.jstatcom.engine.ConfigHolder;
import com.jstatcom.engine.ConfigKeys;
import com.jstatcom.engine.Engine;
import com.jstatcom.engine.EngineTypes;

/**
 * GaussEngineType holds information about the
 * GaussEngine and works as a factory to create an instance of
 * GAUSS. It is a Singleton.
 * 
 * @author Markus Kraetzig 
 */
public final class GaussEngineType extends EngineTypes {
    /**
     * To enforce the Singleton property of this class.
     */
    public static final GaussEngineType INSTANCE = new GaussEngineType("GAUSS");

    private GaussEngine gaussEngine = null;

    private AbstractConfigPanel configPanel = null;

    /**
     * Gets a unique temporary file. The file is created by this method in the
     * temporary directory specified for the respective engine. The prefix is
     * "jsc". It will automatically be deleted when the VM exits
     * normally.
     * 
     * @return the name of a temporary file
     * @throws RuntimeException
     *             if the file could not be created
     */
    public File getTempFile() {

        // Create tmp file.
        String tmpDir = ConfigHolder.valueOf(this).getConfig(
                GaussConfigKeys.TEMP_DIR)
                + "/" + DIR_NAME;
        File tmpFile = null;
        try {
            tmpFile = File.createTempFile("jsc", null, new File(tmpDir));
            tmpFile.deleteOnExit();
        } catch (IOException ex) {
            throw new RuntimeException(ex.getMessage());
        }

        return tmpFile;
    }

    /**
     * GaussEngineType constructor is private to ensure Singleton.
     * 
     * @param name
     *            String
     */
    private GaussEngineType(String name) {
        super(name);
    }

    /**
     * Checks the validity of the configuration for the GaussEngine.
     * 
     * @see com.jstatcom.engine.EngineTypes
     * @throws IllegalArgumentException
     *             if (configHolder == null)
     */
    public String checkSettings(ConfigHolder configHolder) {

        if (configHolder == null)
            throw new IllegalArgumentException("Argument was null.");

        // Test whether Gaussversion fits with specified directory.
        // This is only a distinction between 3.2 and newer Versions
        // and only tests, whether tgauss.exe is there.

        // Test whether the 16 bit restriction for directory names
        // of Gaussversion 3.2 holds. TEMP_DIR, EXE_LOCATION and
        // GCG_FILENAME have to be checked.

        // This is not implemented.

        // if TEMP_DIR is empty, then use system variable TEMP.
        // IF TEMP is also empty, then use TMP

        return null;

    }

    /**
     * @see com.jstatcom.engine.EngineTypes
     */
    public Map getConfigKeys() {
        return ConfigKeys.getAllKeys(GaussConfigKeys.class);

    }

    /**
     * @see com.jstatcom.engine.EngineTypes
     */
    public AbstractConfigPanel getConfigPanel() {
        if (configPanel == null)
            configPanel = new GaussConfigPanel();
        return configPanel;

    }

    /**
     * @see com.jstatcom.engine.EngineTypes
     */
    public Engine getEngine() {
        if (gaussEngine == null) {
            try {
                gaussEngine = GaussEngine.getInstance();
                gaussEngine.start(true);
            } catch (Throwable ex) {
                throw new RuntimeException(
                        "The GAUSS engine could not be initialized\ndue to the following error:\n\n"
                                + ex.getMessage() + "\n");
            }
        }
        addLoadedEngine(gaussEngine);

        return gaussEngine;

    }
}