/* SimpleRuntimeEnvironment Copyright (C) 1999-2002 Jochen Hoenicke.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; see the file COPYING.LESSER.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id$
 */

package net.sf.jode.jvm;
import net.sf.jode.bytecode.Reference;
import net.sf.jode.bytecode.TypeSignature;

import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;

/**
 * This is a runtime environment using reflection.
 * Monitors are not supported by this class so exit/enterMonitor
 * will through an InterpreterException.
 */
public class SimpleRuntimeEnvironment implements RuntimeEnvironment {

    public static Object fromReflectType(String typeSig, Object value) {
	switch(typeSig.charAt(0)) {
	case 'Z':
	    return new Integer(((Boolean) value).booleanValue() ? 1 : 0);
	case 'B': 
	case 'S':
	    return new Integer(((Number) value).intValue());
	case 'C':
	    return new Integer(((Character) value).charValue());
	default:
	    return value;
	}
    }

    public static Object toReflectType(String typeSig, Object value) {
	switch(typeSig.charAt(0)) {
	case 'Z':
	    return new Boolean(((Integer)value).intValue() != 0);
	case 'B':
	    return new Byte(((Integer)value).byteValue());
	case 'S':
	    return new Short(((Integer)value).shortValue());
	case 'C':
	    return new Character((char) ((Integer)value).intValue());
	default:
	    return value;
	}
    }

    public Object getField(Reference ref, Object obj)
	throws InterpreterException {
	Field f;
	try {
	    Class clazz = TypeSignature.getClass(ref.getClazz());
	    try {
		f = clazz.getField(ref.getName());
	    } catch (NoSuchFieldException ex) {
		f = clazz.getDeclaredField(ref.getName());
	    }
	} catch (ClassNotFoundException ex) {
	    throw new InterpreterException
		(ref+": Class not found");
	} catch (NoSuchFieldException ex) {
	    throw new InterpreterException
		("Constructor "+ref+" not found");
	} catch (SecurityException ex) {
	    throw new InterpreterException
		(ref+": Security exception");
	}
	try {
	    return fromReflectType(ref.getType(), f.get(obj));
	} catch (IllegalAccessException ex) {
	    throw new InterpreterException
		("Field " + ref + " not accessible");
	}
    }

    public void putField(Reference ref, Object obj, Object value)
	throws InterpreterException {
	Field f;
	try {
	    Class clazz = TypeSignature.getClass(ref.getClazz());
	    try {
		f = clazz.getField(ref.getName());
	    } catch (NoSuchFieldException ex) {
		f = clazz.getDeclaredField(ref.getName());
	    }
	} catch (ClassNotFoundException ex) {
	    throw new InterpreterException
		(ref+": Class not found");
	} catch (NoSuchFieldException ex) {
	    throw new InterpreterException
		("Constructor "+ref+" not found");
	} catch (SecurityException ex) {
	    throw new InterpreterException
		(ref+": Security exception");
	}
	try {
	    f.set(obj, toReflectType(ref.getType(), value));
	} catch (IllegalAccessException ex) {
	    throw new InterpreterException
		("Field " + ref + " not accessible");
	}
    }
    
    public Object invokeConstructor(Reference ref, Object[] params)
	throws InterpreterException, InvocationTargetException {
	Constructor c;
	try {
	    String[] paramTypeSigs
		= TypeSignature.getParameterTypes(ref.getType());
	    Class clazz = TypeSignature.getClass(ref.getClazz());
	    Class[] paramTypes = new Class[paramTypeSigs.length];
	    for (int i=0; i< paramTypeSigs.length; i++) {
		params[i] = toReflectType(paramTypeSigs[i], params[i]);
		paramTypes[i] = TypeSignature.getClass(paramTypeSigs[i]);
	    }
	    try {
		c = clazz.getConstructor(paramTypes);
	    } catch (NoSuchMethodException ex) {
		c = clazz.getDeclaredConstructor(paramTypes);
	    }
	} catch (ClassNotFoundException ex) {
	    throw new InterpreterException
		(ref+": Class not found");
	} catch (NoSuchMethodException ex) {
	    throw new InterpreterException
		("Constructor "+ref+" not found");
	} catch (SecurityException ex) {
	    throw new InterpreterException
		(ref+": Security exception");
	}
	
	try {
	    return c.newInstance(params);
	} catch (IllegalAccessException ex) {
	    throw new InterpreterException
		("Constructor " + ref + " not accessible");
	} catch (InstantiationException ex) {
	    throw new InterpreterException
		("InstantiationException in " + ref + ".");
	}
    }
    
    public Object invokeMethod(Reference ref, boolean isVirtual, 
			       Object cls, Object[] params) 
	throws InterpreterException, InvocationTargetException {
	if (!isVirtual && cls != null) /*XXX*/
	    throw new InterpreterException
		("Can't invoke nonvirtual Method " + ref + ".");

	Method m;
	try {
	    String[] paramTypeSigs
		= TypeSignature.getParameterTypes(ref.getType());
	    Class clazz = TypeSignature.getClass(ref.getClazz());
	    Class[] paramTypes = new Class[paramTypeSigs.length];
	    for (int i=0; i< paramTypeSigs.length; i++) {
		params[i] = toReflectType(paramTypeSigs[i], params[i]);
		paramTypes[i] = TypeSignature.getClass(paramTypeSigs[i]);
	    }
	    try {
		m = clazz.getMethod(ref.getName(), paramTypes);
	    } catch (NoSuchMethodException ex) {
		m = clazz.getDeclaredMethod(ref.getName(), paramTypes);
	    }
	} catch (ClassNotFoundException ex) {
	    throw new InterpreterException
		(ref+": Class not found");
	} catch (NoSuchMethodException ex) {
	    throw new InterpreterException
		("Method "+ref+" not found");
	} catch (SecurityException ex) {
	    throw new InterpreterException
		(ref+": Security exception");
	}
	String retType = TypeSignature.getReturnType(ref.getType());
	try {
	    return fromReflectType(retType, m.invoke(cls, params));
	} catch (IllegalAccessException ex) {
	    throw new InterpreterException
		("Method " + ref + " not accessible");
	}
    }
    
    public boolean instanceOf(Object obj, String className)
	throws InterpreterException {
	Class clazz;
	try {
	    clazz = Class.forName(className);
	} catch (ClassNotFoundException ex) {
	    throw new InterpreterException
		("Class "+ex.getMessage()+" not found");
	}
	return obj != null && !clazz.isInstance(obj);
    }

    public Object newArray(String type, int[] dimensions)
	throws InterpreterException, NegativeArraySizeException {
	Class clazz;
	try {
	    /* get the base class (strip leading "[") */
	    clazz = TypeSignature.getClass(type.substring(dimensions.length));
	} catch (ClassNotFoundException ex) {
	    throw new InterpreterException
		("Class "+ex.getMessage()+" not found");
	}
	return Array.newInstance(clazz, dimensions);
    }

    public void enterMonitor(Object obj)
	throws InterpreterException {
	throw new InterpreterException("monitor not implemented");
    }
    public void exitMonitor(Object obj)
	throws InterpreterException {
	throw new InterpreterException("monitor not implemented");
    }
}