/*

  * Licensed to the Apache Software Foundation (ASF) under one or more

  * contributor license agreements.  See the NOTICE file distributed with

  * this work for additional information regarding copyright ownership.

  * The ASF licenses this file to You under the Apache 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.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.commons.nabla.forward.instructions;

 import org.apache.commons.math3.analysis.differentiation.DerivativeStructure;

 import org.apache.commons.nabla.DifferentiationException;

 import org.apache.commons.nabla.NablaMessages;

 import org.apache.commons.nabla.forward.analysis.InstructionsTransformer;

 import org.apache.commons.nabla.forward.analysis.MethodDifferentiator;

 import org.objectweb.asm.Opcodes;

 import org.objectweb.asm.Type;

 import org.objectweb.asm.tree.AbstractInsnNode;

 import org.objectweb.asm.tree.InsnList;

 import org.objectweb.asm.tree.InsnNode;

 import org.objectweb.asm.tree.MethodInsnNode;

 /** Differentiation transformer for INVOKESTATIC instructions.

  * @version $Id$

  */

 public class InvokeStaticTransformer implements InstructionsTransformer {

     /** Indicator for top stack element conversion. */

     private final boolean stack0Converted;

     /** Indicator for next to top stack element conversion. */

     private final boolean stack1Converted;

     /** Simple constructor.

      * @param stack0Converted if true, the top level stack element has already been converted

      * @param stack1Converted if true, the next to top level stack element has already been converted

      */

     public InvokeStaticTransformer(final boolean stack0Converted, final boolean stack1Converted) {

         this.stack0Converted = stack0Converted;

         this.stack1Converted = stack1Converted;

     }

     /** {@inheritDoc} */

     public InsnList getReplacement(final AbstractInsnNode insn,

                                    final MethodDifferentiator methodDifferentiator)

         throws DifferentiationException {

         final MethodInsnNode methodInsn = (MethodInsnNode) insn;

         if (!methodDifferentiator.isMathImplementationClass(methodInsn.owner)) {

             // TODO: handle INVOKESTATIC on non math related classes

             throw new RuntimeException("INVOKESTATIC on non math related classes not handled yet" +

                     methodInsn.owner + methodInsn.owner);

         }

         final InsnList list = new InsnList();

         if (methodInsn.desc.equals(Type.getMethodDescriptor(Type.DOUBLE_TYPE, Type.DOUBLE_TYPE))) {

             // this is a univariate method like sin, cos, exp ...

             try {

                 // check that a corresponding method exist for DerivativeStructure

                 DerivativeStructure.class.getDeclaredMethod(methodInsn.name);

             } catch (NoSuchMethodException nsme) {

                 throw new DifferentiationException(NablaMessages.UNKNOWN_METHOD,

                                                    methodInsn.owner, methodInsn.name);

             }

             list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL,

                                         DS_TYPE.getInternalName(), methodInsn.name,

                                         Type.getMethodDescriptor(DS_TYPE)));

         } else if (methodInsn.desc.equals(Type.getMethodDescriptor(Type.DOUBLE_TYPE, Type.DOUBLE_TYPE, Type.DOUBLE_TYPE))) {

             // this is a bivariate method like atan2, pow ...

             if (methodInsn.name.equals("pow")) {

                 // special case for pow: in DerivativeStructure, it is an instance method,

                 // not a static method as the other two parameters functions like atan2 or hypot

                 if (stack1Converted) {

                     if (!stack0Converted) {

                         list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL,

                                                     DS_TYPE.getInternalName(), methodInsn.name,

                                                     Type.getMethodDescriptor(DS_TYPE, Type.DOUBLE_TYPE)));

                     } else {

                         list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL,

                                                     DS_TYPE.getInternalName(), methodInsn.name,

                                                     Type.getMethodDescriptor(DS_TYPE, DS_TYPE)));

                     }

                 } else {

                     // initial stack state: x, ds_y

                     list.add(new InsnNode(Opcodes.DUP_X2));                                 // => ds_y, x, ds_y

                     list.add(new InsnNode(Opcodes.POP));                                    // => ds_y, x

                     list.add(methodDifferentiator.doubleToDerivativeStructureConversion()); // => ds_y, ds_x

                     list.add(new InsnNode(Opcodes.SWAP));                                   // => ds_x, ds_y

                     // call the static two parameters method for DerivativeStructure

                     list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL,

                                                 DS_TYPE.getInternalName(), methodInsn.name,

                                                 Type.getMethodDescriptor(DS_TYPE, DS_TYPE)));

                 }

             } else {

                 if (stack1Converted) {

                     if (!stack0Converted) {

                         // the top level element is not a DerivativeStructure, convert it

                         list.add(methodDifferentiator.doubleToDerivativeStructureConversion());

                     }

                 } else {

                     // initial stack state: x, ds_y

                     list.add(new InsnNode(Opcodes.DUP_X2));                                 // => ds_y, x, ds_y

                     list.add(new InsnNode(Opcodes.POP));                                    // => ds_y, x

                     list.add(methodDifferentiator.doubleToDerivativeStructureConversion()); // => ds_y, ds_x

                     list.add(new InsnNode(Opcodes.SWAP));                                   // => ds_x, ds_y

                 }

                 // call the static two parameters method for DerivativeStructure

                 list.add(new MethodInsnNode(Opcodes.INVOKESTATIC,

                                             DS_TYPE.getInternalName(), methodInsn.name,

                                             Type.getMethodDescriptor(DS_TYPE, DS_TYPE, DS_TYPE)));

             }

         } else {

             throw new DifferentiationException(NablaMessages.UNKNOWN_METHOD,

                                                methodInsn.owner, methodInsn.name);

         }

         return list;

     }

 }