**** 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.PrintStream;
import java.io.Writer;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import javax.script.Bindings;
import javax.script.ScriptContext;
import javax.script.ScriptEngine;
import org.jruby.Ruby;
import org.jruby.RubyGlobal.OutputGlobalVariable;
import org.jruby.RubyIO;
import org.jruby.embed.AttributeName;
import org.jruby.embed.LocalVariableBehavior;
import org.jruby.embed.ScriptingContainer;
import org.jruby.embed.io.WriterOutputStream;
import org.jruby.embed.variable.TransientLocalVariable;
import org.jruby.embed.variable.VariableInterceptor;
import org.jruby.internal.runtime.GlobalVariable;

A collection of JSR223 specific utility methods.
Author:
Yoko Harada /**
 * A collection of JSR223 specific utility methods.
 *
 * @author Yoko Harada <yokolet@gmail.com>
 */
public class Utils {
    
Gets line number value from engine's attribute map.
Params:
context – ScriptContext to be used to the evaluation
Returns:
line number/**
     * Gets line number value from engine's attribute map.
     *
     * @param context ScriptContext to be used to the evaluation
     * @return line number
     */
    static int getLineNumber(ScriptContext context) {
        Object obj = context.getAttribute(AttributeName.LINENUMBER.toString(), ScriptContext.ENGINE_SCOPE);
        if (obj instanceof Integer) {
            return (Integer) obj;
        }
        return 0;
    }

    
Gets a receiver object from engine's attribute map.
Params:
context – ScriptContext to be used to the evaluation
Returns:
receiver object or null if the attribute doesn't exist/**
     * Gets a receiver object from engine's attribute map.
     *
     * @param context ScriptContext to be used to the evaluation
     * @return receiver object or null if the attribute doesn't exist
     */
    static Object getReceiver(ScriptContext context) {
        return context.getAttribute(AttributeName.RECEIVER.toString(), ScriptContext.ENGINE_SCOPE);
    }

    static String getFilename(ScriptContext context) {
        Object filename = context.getAttribute(ScriptEngine.FILENAME);
        return filename != null ? (String)filename : "<script>";
    }

    static boolean isTerminationOn(ScriptContext context) {
        Object obj = context.getAttribute(AttributeName.TERMINATION.toString());
        if (obj != null && obj instanceof Boolean && ((Boolean) obj) == true) {
            return true;
        }
        return false;
    }
    
    static boolean isClearVariablesOn(ScriptContext context) {
        Object obj = context.getAttribute(AttributeName.CLEAR_VARAIBLES.toString());
        if (obj != null && obj instanceof Boolean && ((Boolean) obj) == true) {
            return true;
        }
        return false;
    }

    static void preEval(ScriptingContainer container, ScriptContext context) {
        Object receiver = Utils.getReceiverObject(context);

        Bindings bindings = context.getBindings(ScriptContext.ENGINE_SCOPE);
        for (Map.Entry<String, Object> entry : bindings.entrySet()) {
            put(container, receiver, entry.getKey(), entry.getValue(), context);
        }

        //container.setReader(context.getReader());
        setStdOut(container, context.getWriter());
        setStdErr(container, context.getErrorWriter());

        // if key of globalMap exists in engineMap, this key-value pair should be skipped.
        bindings = context.getBindings(ScriptContext.GLOBAL_SCOPE);
        if (bindings == null) return;
        for (Map.Entry<String, Object> entry : bindings.entrySet()) {
            if (container.getVarMap().containsKey(entry.getKey())) continue;
            put(container, receiver, entry.getKey(), entry.getValue(), context);
        }
    }

    private static Object getReceiverObject(ScriptContext context) {
        if (context == null) return null;
        return context.getAttribute(AttributeName.RECEIVER.toString(), ScriptContext.ENGINE_SCOPE);
    }
    
    private static void setStdOut(ScriptingContainer container, Writer writer) {
        if (writer == null) {
            return;
        }
        Map map = container.getAttributeMap();
        if (map.containsKey(AttributeName.WRITER)) {
            Writer old = (Writer) map.get(AttributeName.WRITER);
            if (old == writer) {
                return;
            }
        }
        map.put(AttributeName.WRITER, writer);
        
        Ruby runtime = container.getProvider().getRuntime();
        RubyIO io = getRubyIO(runtime, writer);
        runtime.defineVariable(new OutputGlobalVariable(runtime, "$stdout", io), GlobalVariable.Scope.GLOBAL);
        runtime.getObject().storeConstant("STDOUT", io);
        runtime.getGlobalVariables().alias("$>", "$stdout");
        runtime.getGlobalVariables().alias("$defout", "$stdout");
    }
    
    private static void setStdErr(ScriptingContainer container, Writer writer) {
        if (writer == null) {
            return;
        }
        Map map = container.getAttributeMap();
        if (map.containsKey(AttributeName.ERROR_WRITER)) {
            Writer old = (Writer) map.get(AttributeName.ERROR_WRITER);
            if (old == writer) {
                return;
            }
        }
        map.put(AttributeName.ERROR_WRITER, writer);
        
        Ruby runtime = container.getProvider().getRuntime();
        RubyIO io = getRubyIO(runtime, writer);
        runtime.defineVariable(new OutputGlobalVariable(runtime, "$stderr", io), GlobalVariable.Scope.GLOBAL);
        runtime.getObject().storeConstant("STDERR", io);
        runtime.getGlobalVariables().alias("$deferr", "$stderr");
    }
    
    private static RubyIO getRubyIO(Ruby runtime, Writer writer) {
        PrintStream stream = new PrintStream(new WriterOutputStream(writer, runtime.getDefaultCharset().name()), true);
        RubyIO io = new RubyIO(runtime, stream, false);
        boolean locked = io.getOpenFile().lock();
        try {
            io.getOpenFile().setSync(true);
            io.getOpenFile().io_fflush(runtime.getCurrentContext());
            return io;
        } finally {
            if (locked) io.getOpenFile().unlock();
        }
    }

    static void postEval(ScriptingContainer container, ScriptContext context) {
        if (context == null) return;
        Object receiver = Utils.getReceiverObject(context);

        Bindings engineMap = context.getBindings(ScriptContext.ENGINE_SCOPE);
        Iterator<Map.Entry<String, Object>> iter = engineMap.entrySet().iterator();
        for (;iter.hasNext();) {
            Map.Entry<String, Object> entry = iter.next();
            if (Utils.shouldLVarBeDeleted(container, entry.getKey())) {
                iter.remove();
            }
        }
        Set<String> keys = container.getVarMap().keySet();
        if (keys != null && keys.size() > 0) {
            for (String key : keys) {
                Object value = container.getVarMap().get(key);
                engineMap.put(Utils.adjustKey(key), value);
            }
        }

        Bindings globalMap = context.getBindings(ScriptContext.GLOBAL_SCOPE);
        if (globalMap == null) return;
        keys = globalMap.keySet();
        if (keys != null && keys.size() > 0) {
            for (String key : keys) {
                if (engineMap.containsKey(key)) continue;
                Object value = container.getVarMap().get(receiver, key);
                globalMap.put(key, value);
            }
        }
    }

    private static Object put(ScriptingContainer container, Object receiver, String key, Object value, ScriptContext context) {
        Object oldValue = null;
        String adjustedKey = Utils.adjustKey(key);
        if (Utils.isRubyVariable(container, adjustedKey)) {
            boolean sharing_variables = true;
            Object obj = context.getAttribute(AttributeName.SHARING_VARIABLES.toString(), ScriptContext.ENGINE_SCOPE);
            if (obj != null && obj instanceof Boolean && ((Boolean) obj) == false) {
                sharing_variables = false;
            }
            if (sharing_variables || "ARGV".equals(adjustedKey)) {
                oldValue = container.put(receiver, adjustedKey, value);
            }
        } else {
            if (adjustedKey.equals(AttributeName.SHARING_VARIABLES.toString())) {
                oldValue = container.setAttribute(AttributeName.SHARING_VARIABLES, value);
            } else {
                oldValue = container.setAttribute(adjustedKey, value);
            }
        }
        return oldValue;
    }

    static boolean isRubyVariable(ScriptingContainer container, String name) {
        return VariableInterceptor.isKindOfRubyVariable(container.getProvider().getLocalVariableBehavior(), name);
    }

    private static String adjustKey(String key) {
        if (key.equals(ScriptEngine.ARGV)) {
            return "ARGV";
        } if ("ARGV".equals(key)) {
            return ScriptEngine.ARGV;
        } else {
            return key;
        }
    }
    
    private static boolean shouldLVarBeDeleted(ScriptingContainer container, String key) {
        LocalVariableBehavior behavior = container.getProvider().getLocalVariableBehavior();
        if (behavior != LocalVariableBehavior.TRANSIENT) return false;
        return TransientLocalVariable.isValidName(key);
    }
}