/***** BEGIN LICENSE BLOCK *****
 * Version: CPL 1.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Common Public
 * License Version 1.0 (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/cpl-v10.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) 2002 Jan Arne Petersen <jpetersen@uni-bonn.de>
 * Copyright (C) 2002-2004 Anders Bengtsson <ndrsbngtssn@yahoo.se>
 * Copyright (C) 2005 Thomas E Enebo <enebo@acm.org>
 * 
 * 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
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 * use your version of this file under the terms of the CPL, 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 CPL, the GPL or the LGPL.
 ***** END LICENSE BLOCK *****/
package org.jruby.internal.runtime.methods;

import org.jruby.RubyModule;
import org.jruby.runtime.Arity;
import org.jruby.runtime.Block;
import org.jruby.runtime.CallType;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.Visibility;
import org.jruby.runtime.builtin.IRubyObject;

/**
 *
 * @author  jpetersen
 */
public abstract class DynamicMethod {
    protected RubyModule implementationClass;
    protected Visibility visibility;
    private boolean needsImplementer;
    
    protected DynamicMethod(RubyModule implementationClass, Visibility visibility) {
        this.visibility = visibility;
        this.implementationClass = implementationClass;
        if (implementationClass != null) {
            boolean implIsClass = implementationClass.isClass();
            boolean implIsKernel = implementationClass == implementationClass.getRuntime().getKernel();
            needsImplementer = !(implIsClass || implIsKernel);
        }
    }

    /**
     * Call the method
     * @param context is the thread-specific information that this method is being invoked on
     * @param receiver 
     */
    public IRubyObject call(ThreadContext context, IRubyObject self, RubyModule clazz, 
            String name, IRubyObject[] args, boolean noSuper, Block block) {
        // FIXME: this potentially should go in overridden call impls too, but so far it hasn't appeared to be necessary
        RubyModule implementer = null;
        if (needsImplementer) {
            // modules are included with a shim class; we must find that shim to handle super() appropriately
            implementer = clazz.findImplementer(getImplementationClass());
        } else {
            // classes are directly in the hierarchy, so no special logic is necessary for implementer
            implementer = getImplementationClass();
        }
        
        preMethod(context, implementer, self, name, args, noSuper, block);

        try {
            return internalCall(context, implementer, self, name, args, noSuper, block);
        } finally {
            postMethod(context);
        }
    }
    
    protected abstract void postMethod(ThreadContext context);
    protected abstract IRubyObject internalCall(ThreadContext context, RubyModule clazz, IRubyObject self, String name, IRubyObject[] args, boolean noSuper, Block block);
    protected abstract void preMethod(ThreadContext context, RubyModule clazz, IRubyObject self, String name, IRubyObject[] args, boolean noSuper, Block block);
    public abstract DynamicMethod dup();

    public boolean isCallableFrom(IRubyObject caller, CallType callType) {
        if (getVisibility().isPrivate() && (callType == CallType.NORMAL)) {
            return false;
        } else if (getVisibility().isProtected()) {
            RubyModule defined = getImplementationClass();
            while (defined.isIncluded()) {
                defined = defined.getMetaClass();
            }

            if (!caller.isKindOf(defined)) return false;
        }
        
        return true;
    }
    
    public RubyModule getImplementationClass() {
        return implementationClass;
    }

    public void setImplementationClass(RubyModule implClass) {
        implementationClass = implClass;
    }

    public Visibility getVisibility() {
        return visibility;
    }

    public void setVisibility(Visibility visibility) {
        this.visibility = visibility;
    }

    public boolean isUndefined() {
        return false;
    }

    public Arity getArity() {
        return Arity.optional();
    }
    
    public DynamicMethod getRealMethod() {
        return this;
    }
}