/*
 * Copyright (c) 1997, 2019 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0, which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.glassfish.pfl.dynamic.copyobject.impl ;

import static java.lang.reflect.Modifier.PRIVATE;
import static java.lang.reflect.Modifier.PUBLIC;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper.DUMP_AFTER_SETUP_VISITOR;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper.TRACE_BYTE_CODE_GENERATION;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper.USE_ASM_VERIFIER;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._Object;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._arg;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._assign;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._body;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._boolean;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._call;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._class;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._clear;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._const;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._constructor;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._data;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._end;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._expr;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._generate;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._if;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._method;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._ne;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._null;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._package;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._super;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._this;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper._void;
import static org.glassfish.pfl.dynamic.codegen.spi.Wrapper.splitClassName;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.ProtectionDomain;
import java.util.Map;
import java.util.Properties;
import org.glassfish.pfl.basic.contain.Pair;
import org.glassfish.pfl.basic.reflection.Bridge;
import org.glassfish.pfl.dynamic.codegen.spi.Expression;
import org.glassfish.pfl.dynamic.codegen.spi.Type;
import org.glassfish.pfl.dynamic.copyobject.spi.ReflectiveCopyException;

Experimental class that generates a ClassFieldCopier using the codegen library.
/** Experimental class that generates a ClassFieldCopier using the codegen library.
 */
public class CodegenCopierGenerator {
    private static final String DEBUG = "false" ;

    private Class<?>	       classToCopy ;
    private String	       className ;

    private static final Bridge bridge = AccessController.doPrivileged(
					(PrivilegedAction<Bridge>) Bridge::get
		) ;

    CodegenCopierGenerator(String className, Class<?> classToCopy) {
	this.className = className ;
	this.classToCopy = classToCopy ;
    }

    public Class<?> create( ProtectionDomain pd, ClassLoader cl ) {
	_clear() ;

	Pair<String,String> pc = splitClassName( className ) ;
	_package( pc.first() ) ;

	Type PipelineClassCopierFactory = Type.type(
	    PipelineClassCopierFactory.class ) ;
	Type ReflectiveCopyException = Type.type( 
	    ReflectiveCopyException.class ) ;
	Type CodegenCopierBase = Type.type( 
	    CodegenCopierBase.class ) ;
	Type ClassFieldCopier = Type.type( 
	    ClassCopierOrdinaryImpl.ClassFieldCopier.class ) ;
	Type Map = Type.type(
	    Map.class ) ;

	_class( PUBLIC, pc.second(), CodegenCopierBase ) ;
	    // XXX Can we get rid of this, and instead just emit copy calls for
	    // superclass fields?
	    Expression superCopier = _data( PRIVATE, ClassFieldCopier, "superCopier" ) ;

	    _constructor( PUBLIC ) ;
		Expression factory = _arg( PipelineClassCopierFactory, "factory" ) ;
		Expression sc = _arg( ClassFieldCopier, "superCopier" ) ;
	    _body() ;
		_super( factory ) ;
		_assign( superCopier, sc ) ;
	    _end() ;

	    _method( PUBLIC, _void(), "copy", ReflectiveCopyException ) ;
		Expression oldToNew = _arg( Map, "oldToNew" ) ;
		Expression src      = _arg( _Object(), "src" ) ;
		Expression dest     = _arg( _Object(), "dest" ) ;
		Expression debug    = _arg( _boolean(), "debug" ) ;
	    _body() ;
		_if(_ne(superCopier, _null())) ;
		    _expr(_call( superCopier, "copy", oldToNew, src, dest, debug )) ; 
		_end() ;

		// Generate code to copy fields of this object
		for (Field fld : classToCopy.getDeclaredFields()) {
		    if (!Modifier.isStatic( fld.getModifiers())) {
			long offset = bridge.objectFieldOffset( fld ) ;
			String mname = getCopyMethodName( fld.getType() ) ;
			if (mname.equals( "copyObject" ))  {
			    _expr(_call( _this(), mname, oldToNew, _const(offset), 
				src, dest )) ;
			} else {
			    _expr(_call( _this(), mname, _const(offset), 
				src, dest )) ;
			}
		    }
		}
	    _end() ;
	_end() ;

	Properties debugProps = new Properties() ;
	debugProps.setProperty( DUMP_AFTER_SETUP_VISITOR, DEBUG ) ;
	debugProps.setProperty( TRACE_BYTE_CODE_GENERATION, DEBUG ) ;
	debugProps.setProperty( USE_ASM_VERIFIER, DEBUG ) ;
	
	Class<?> cls = _generate( cl, pd, debugProps ) ;
	return cls ;
    }

    private String getCopyMethodName( Class<?> fieldType ) {
	if (fieldType.equals( Boolean.TYPE )) {
            return "copyBoolean";
        } else if (fieldType.equals( Byte.TYPE )) {
            return "copyByte";
        } else if (fieldType.equals( Character.TYPE )) {
            return "copyChar";
        } else if (fieldType.equals( Integer.TYPE )) {
            return "copyInt";
        } else if (fieldType.equals( Short.TYPE )) {
            return "copyShort";
        } else if (fieldType.equals( Long.TYPE )) {
            return "copyLong";
        } else if (fieldType.equals( Float.TYPE )) {
            return "copyFloat";
        } else if (fieldType.equals( Double.TYPE )) {
            return "copyDouble";
        } else {
            return "copyObject";
        }
    }
}