**** 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) 2009-2011 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) 2009-2011 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.InputStreamReader;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.script.Bindings;
import javax.script.ScriptContext;
import javax.script.SimpleBindings;
import org.jruby.embed.ScriptingContainer;

Implementation of javax.script.ScriptContext.
Author:
Yoko Harada /**
 * Implementation of javax.script.ScriptContext.
 * 
 * @author Yoko Harada <yokolet@gmail.com>
 */
class JRubyContext implements ScriptContext {
    private ScriptingContainer container;
    private final List<Integer> scopeList;
    private Bindings globalMap = null;
    private Bindings engineMap = new SimpleBindings();
    private Reader reader = null;
    private Writer writer = null;
    private Writer errorWriter = null;
    
    public enum Scope {

        ENGINE(ScriptContext.ENGINE_SCOPE),
        GLOBAL(ScriptContext.GLOBAL_SCOPE);
        private final int priority;

        Scope(int priority) {
            this.priority = priority;
        }

        int getPriority() {
            return priority;
        }
    }

    JRubyContext(ScriptingContainer container) {
        this.container = container;
        List<Integer> list = new ArrayList<Integer>();
        for (Scope scope : Scope.values()) {
            list.add(scope.getPriority());
        }
        scopeList = Collections.unmodifiableList(list);
    }

    private void checkName(String name) {
        if (name == null) {
            throw new NullPointerException("name is null");
        }
        if (name.length() == 0) {
            throw new IllegalArgumentException("name is empty");
        }
    }

    public Object getAttribute(String name) {
        Object ret = null;
        for (Scope scope : Scope.values()) {
            ret = getAttributeFromScope(scope.getPriority(), name);
            if (ret != null) {
                return ret;
            }
        }
        return ret;
    }

    private Object getAttributeFromScope(int priority, String name) {
        checkName(name);
        Object value;
        if (priority == Scope.ENGINE.getPriority()) {
            value = engineMap.get(name);
            if (value == null && Utils.isRubyVariable(container, name)) {
                value = container.get(Utils.getReceiver(this), name);
                engineMap.put(name, value);
            }
            return value;
        } else if (priority == Scope.GLOBAL.getPriority()) {
            if (globalMap == null) {
                return null;
            }
            return globalMap.get(name);
        } else {
            throw new IllegalArgumentException("invalid scope");
        }
    }

    public Object getAttribute(String name, int scope) {
        return getAttributeFromScope(scope, name);
    }

    public int getAttributesScope(String name) {
        for (Scope scope : Scope.values()) {
            Object ret = getAttributeFromScope(scope.getPriority(), name);
            if (ret != null) {
                return scope.getPriority();
            }
        }
        return -1;
    }

    public Bindings getBindings(int priority) {
        if (priority == Scope.ENGINE.getPriority()) {
            return engineMap;
        } else if (priority == Scope.GLOBAL.getPriority()) {
            return globalMap;
        } else {
            throw new IllegalArgumentException("invalid scope");
        }
    }

    Bindings getEngineScopeBindings() {
        return engineMap;
    }

    Bindings getGlobalScopeBindings() {
        return globalMap;
    }

    public Writer getErrorWriter() {
        return errorWriter;
    }

    public Reader getReader() {
        return reader;
    }

    public List<Integer> getScopes() {
        return scopeList;
    }

    public Writer getWriter() {
        return writer;
    }

    public Object removeAttribute(String name, int priority) {
        checkName(name);
        Bindings bindings = getBindings(priority);
        if (bindings == null) {
            return null;
        }
        return bindings.remove(name);
    }

    public void setAttribute(String key, Object value, int priority) {
        Bindings bindings = getBindings(priority);
        if (bindings == null) {
            return;
        }
        bindings.put(key, value);
    }

    public void setBindings(Bindings bindings, int scope) {
        if (scope == Scope.ENGINE.getPriority() && bindings == null) {
            throw new NullPointerException("null bindings in ENGINE scope");
        }
        if (scope == Scope.ENGINE.getPriority()) {
            engineMap = bindings;
        } else if (scope == Scope.GLOBAL.getPriority()) {
            globalMap = bindings;
        } else {
            throw new IllegalArgumentException("invalid scope");
        }
    }

    void setEngineScopeBindings(Bindings bindings) {
        engineMap = bindings;
    }

    void setGlobalScopeBindings(Bindings bindings) {
        globalMap = bindings;
    }

    public void setErrorWriter(Writer errorWriter) {
        if (errorWriter == null) {
            return;
        }
        if (getErrorWriter() == errorWriter) {
            return;
        }
        this.errorWriter = errorWriter;
    }

    public void setReader(Reader reader) {
        setReader(reader, true);
    }

    void setReader(Reader reader, boolean updateContainer) {
        if (reader == null) {
            return;
        }
        if (getReader() == reader) {
            return;
        }
        this.reader = reader;
    }

    public void setWriter(Writer writer) {
        if (writer == null) {
            return;
        }
        if (getWriter() == writer) {
            return;
        }
        this.writer = writer;
    }
}