**** 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) 2009-2012 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) 2009-2012 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.io.Reader;
import javax.script.Bindings;
import javax.script.Compilable;
import javax.script.CompiledScript;
import javax.script.Invocable;
import javax.script.ScriptContext;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;
import javax.script.ScriptException;
import javax.script.SimpleBindings;
import javax.script.SimpleScriptContext;
import org.jruby.embed.EmbedEvalUnit;
import org.jruby.embed.ScriptingContainer;
import org.jruby.javasupport.JavaEmbedUtils;
import org.jruby.runtime.builtin.IRubyObject;

Implementation of javax.script.ScriptEngine/Compilable/Invocable.
Author:
Yoko Harada /**
 * Implementation of javax.script.ScriptEngine/Compilable/Invocable.
 *
 * @author Yoko Harada <yokolet@gmail.com>
 */
public class JRubyEngine implements Compilable, Invocable, ScriptEngine {

    final ScriptingContainer container;
    private JRubyEngineFactory factory;
    private ScriptContext context;

    JRubyEngine(ScriptingContainer container, JRubyEngineFactory factory) {
        this.container = container;
        this.factory = factory;
        this.context = new JRubyContext(container);
    }

    public CompiledScript compile(String script) throws ScriptException {
        if (script == null) {
            throw new NullPointerException("script is null");
        }
        return new JRubyCompiledScript(container, this, script);
    }

    public CompiledScript compile(Reader reader) throws ScriptException {
        if (reader == null) {
            throw new NullPointerException("reader is null");
        }
        return new JRubyCompiledScript(container, this, reader);
    }

    public Object eval(String script, ScriptContext context) throws ScriptException {
        if (script == null || context == null) {
            throw new NullPointerException("either script or context is null");
        }
        container.setScriptFilename(Utils.getFilename(context));
        try {
            if (Utils.isClearVariablesOn(context)) {
                container.clear();
            }
            Utils.preEval(container, context);
            EmbedEvalUnit unit = container.parse(script, Utils.getLineNumber(context));
            IRubyObject ret = unit.run();
            return JavaEmbedUtils.rubyToJava(ret);
        } catch (Exception e) {
            throw wrapException(e);
        } finally {
            Utils.postEval(container, context);
            boolean termination = Utils.isTerminationOn(context);
            if (termination) {
                container.terminate();
            }
        }
    }

    private ScriptException wrapException(Exception e) {
        return new ScriptException(e);
    }

    public Object eval(Reader reader, ScriptContext context) throws ScriptException {
        if (reader == null || context == null) {
            throw new NullPointerException("either reader or context is null");
        }
        String filename = Utils.getFilename(context);
        try {
            if (Utils.isClearVariablesOn(context)) {
                container.clear();
            }
            Utils.preEval(container, context);
            EmbedEvalUnit unit = container.parse(reader, filename, Utils.getLineNumber(context));
            IRubyObject ret = unit.run();
            return JavaEmbedUtils.rubyToJava(ret);
        } catch (Exception e) {
            throw wrapException(e);
        } finally {
            Utils.postEval(container, context);
            boolean termination = Utils.isTerminationOn(context);
            if (termination) {
                container.terminate();
            }
        }
    }

    public Object eval(String script, Bindings bindings) throws ScriptException {
        ScriptContext context = getScriptContext(bindings);
        return eval(script, context);
    }

    public Object eval(Reader reader, Bindings bindings) throws ScriptException {
        ScriptContext context = getScriptContext(bindings);
        return eval(reader, context);
    }

    public Object eval(String script) throws ScriptException {
        return eval(script, context);
    }

    public Object eval(Reader reader) throws ScriptException {
        return eval(reader, context);
    }

    protected ScriptContext getScriptContext(Bindings bindings) {
        if (bindings == null) {
            throw new NullPointerException("null bindings in engine scope");
        }

        ScriptContext newContext = new SimpleScriptContext();
        newContext.setBindings(bindings, ScriptContext.ENGINE_SCOPE);
        Bindings global = getBindings(ScriptContext.GLOBAL_SCOPE);
        if (global != null) {
            newContext.setBindings(global, ScriptContext.GLOBAL_SCOPE);
        }
        newContext.setReader(context.getReader());
        newContext.setWriter(context.getWriter());
        newContext.setErrorWriter(context.getErrorWriter());

        return newContext;
    }

    public Object get(String key) {
        return context.getAttribute(key, ScriptContext.ENGINE_SCOPE);
    }

    public void put(String key, Object value) {
        context.getBindings(ScriptContext.ENGINE_SCOPE).put(key, value);
    }

    public Bindings getBindings(int scope) {
        return context.getBindings(scope);
    }

    public void setBindings(Bindings bindings, int scope) {
        context.setBindings(bindings, scope);
    }

    public Bindings createBindings() {
        return new SimpleBindings();
    }

    public ScriptContext getContext() {
        return context;
    }

    public void setContext(ScriptContext ctx) {
        if (ctx == null) {
            throw new NullPointerException("context is null");
        }
        context = ctx;
    }

    public ScriptEngineFactory getFactory() {
        return factory;
    }

    public Object invokeMethod(Object receiver, String method, Object... args)
            throws ScriptException, NoSuchMethodException {
        if (method == null) {
            throw new NullPointerException("method is null");
        }
        if (receiver == null) {
            throw new NullPointerException("receiver is null");
        }
        try {
            Utils.preEval(container, context);
            if (args == null || args.length == 0) {
                return container.callMethod(receiver, method, Object.class);
            }
            return container.callMethod(receiver, method, args, Object.class);
        } catch (Exception e) {
            if (e.getCause() != null && e.getCause().getMessage() != null
                    && e.getCause().getMessage().contains("undefined method")) {
                throw wrapMethodException(e);
            }
            throw wrapException(e);
        } finally {
            Utils.postEval(container, context);
        }
    }

    private static NoSuchMethodException wrapMethodException(Exception e) {
        return (NoSuchMethodException) new NoSuchMethodException(e.getCause().getMessage()).initCause(e);
    }

    public Object invokeFunction(String method, Object... args)
            throws ScriptException, NoSuchMethodException {
        if (method == null) {
            throw new NullPointerException("method is null");
        }
        try {
            Utils.preEval(container, context);
            if (args == null || args.length == 0) {
                return container.callMethod(container.getProvider().getRuntime().getTopSelf(), method, Object.class);
            }
            return container.callMethod(container.getProvider().getRuntime().getTopSelf(), method, args, Object.class);
        } catch (Exception e) {
            if (e.getCause() != null && e.getCause().getMessage() != null
                    && e.getCause().getMessage().contains("undefined method")) {
                throw wrapMethodException(e);
            }
            throw wrapException(e);
        } finally {
            Utils.postEval(container, context);
        }
    }

    public <T> T getInterface(Class<T> returnType) {
        return getInterface(null, returnType);
    }

    public <T> T getInterface(Object receiver, Class<T> returnType) {
        return container.getInstance(receiver, returnType);
    }
}