**** BEGIN LICENSE BLOCK *****
Version: EPL 2.0/GPL 2.0/LGPL 2.1
The contents of this file are subject to the Eclipse Public
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.eclipse.org/legal/epl-v20.html
Software distributed under the License is distributed on an "AS
IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
implied. See the License for the specific language governing
rights and limitations under the License.
Copyright (C) 2009-2010 Yoko Harada 
Alternatively, the contents of this file may be used under the terms of
either of the GNU General Public License Version 2 or later (the "GPL"),
or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
in which case the provisions of the GPL or the LGPL are applicable instead
of those above. If you wish to allow use of your version of this file only
under the terms of either the GPL or the LGPL, and not to allow others to
use your version of this file under the terms of the EPL, indicate your
decision by deleting the provisions above and replace them with the notice
and other provisions required by the GPL or the LGPL. If you do not delete
the provisions above, a recipient may use your version of this file under
the terms of any one of the EPL, the GPL or the LGPL.
 **** END LICENSE BLOCK *****
/**
 * **** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * 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.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2009-2010 Yoko Harada <yokolet@gmail.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the EPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the EPL, the GPL or the LGPL.
 * **** END LICENSE BLOCK *****
 */
package org.jruby.embed.jsr223;

import java.text.MessageFormat;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;
import org.jruby.embed.LocalContextScope;
import org.jruby.embed.ScriptingContainer;
import org.jruby.embed.LocalVariableBehavior;
import org.jruby.embed.util.SystemPropertyCatcher;

This class implements javax.script.ScriptEngineFactory.
Author:
Yoko Harada /**
 * This class implements javax.script.ScriptEngineFactory.
 * 
 * @author Yoko Harada <yokolet@gmail.com>
 */
public class JRubyEngineFactory implements ScriptEngineFactory {
    private final String engineName;
    private final String engineVersion;
    private final List<String> extensions;
    private final String languageName;
    //setting languageVersion in constructor causes runtime initialization before setting all configs.
    //changed to get info on demand.
    private String languageVersion;
    private final List<String> mimeTypes;
    private final List<String> engineIds;
    private Map<String, Object> parameters;

    public JRubyEngineFactory() {
        engineName = "JSR 223 JRuby Engine";
        engineVersion = org.jruby.runtime.Constants.VERSION;
        extensions = Collections.unmodifiableList(Arrays.asList(new String[]{"rb"}));
        languageName = "ruby";
        languageVersion = "jruby " + org.jruby.runtime.Constants.VERSION;
        mimeTypes = Collections.unmodifiableList(Arrays.asList(new String[]{"application/x-ruby"}));
        engineIds = Collections.unmodifiableList(Arrays.asList(new String[]{"ruby", "jruby"}));
        // does followings on demand to avoid runtime initialization
        //languageVersion = container.getSupportedRubyVersion();
    }

    private void initParameters() {
        parameters = new HashMap();
        parameters.put(ScriptEngine.ENGINE, getEngineName());
        parameters.put(ScriptEngine.ENGINE_VERSION, getEngineVersion());
        parameters.put(ScriptEngine.NAME, getEngineName());
        parameters.put(ScriptEngine.LANGUAGE, getLanguageName());
        parameters.put(ScriptEngine.LANGUAGE_VERSION, getLanguageVersion());
        parameters.put("THREADING", "THREAD-ISOLATED");
    }

    public String getEngineName() {
        return engineName;
    }

    public String getEngineVersion() {
        return engineVersion;
    }

    public List getExtensions() {
        return extensions;
    }

    public String getLanguageName() {
        return languageName;
    }

    public String getLanguageVersion() {
        return languageVersion;
    }

    public String getMethodCallSyntax(String obj, String m, String... args) {
        if (m == null || m.length() == 0) {
            return "";
        }
        if (args == null || args.length == 0) {  // no argument
            if (obj == null || obj.length() == 0) {
                return MessageFormat.format("{0}", m); //top level method
            } else {
                return MessageFormat.format("{0}.{1}", obj, m);
            }
        } else {  // with argument(s)
            StringBuilder builder = new StringBuilder();
            boolean first = true;
            for (String arg : args) {
                if (!first) {
                    builder.append(", ");
                }
                first = false;
                builder.append(arg);
            }
            if (obj == null || obj.length() == 0) {
                return MessageFormat.format("{0}({1})", m, builder.toString()); //top level method
            } else {
                return MessageFormat.format("{0}.{1}({2})", obj, m, builder.toString());
            }
        }
    }

    public List getMimeTypes() {
        return mimeTypes;
    }

    public List getNames() {
        return engineIds;
    }

    public String getOutputStatement(String toDisplay) {
        if (toDisplay == null || toDisplay.length() == 0) {
            return "";
        }
        return "puts " + toDisplay + "\nor\nprint " + toDisplay;
    }

    public Object getParameter(String key) {
        if (parameters == null) {
            initParameters();
        }
        return parameters.get(key);
    }

    public String getProgram(String... statements) {
        if (statements == null || statements.length == 0) {
            return "";
        }
        StringBuffer sb = new StringBuffer();
        for (String s : statements) {
            sb.append(s);
            sb.append("\n");
        }
        return new String(sb);
    }

    public ScriptEngine getScriptEngine() {
        LocalContextScope scope = SystemPropertyCatcher.getScope(LocalContextScope.SINGLETON);
        LocalVariableBehavior behavior = SystemPropertyCatcher.getBehavior(LocalVariableBehavior.PERSISTENT);
        boolean lazy = SystemPropertyCatcher.isLazy(false);
        ScriptingContainer container = new ScriptingContainer(scope, behavior, lazy);
        SystemPropertyCatcher.setClassLoader(container);
        SystemPropertyCatcher.setConfiguration(container);
        JRubyEngine engine = new JRubyEngine(container, this);
        return (ScriptEngine)engine;
    }

}