/*
 * Copyright 2014 - 2020 Rafael Winterhalter
 *
 * Licensed 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 net.bytebuddy.dynamic.scaffold.inline;

import net.bytebuddy.ClassFileVersion;
import net.bytebuddy.build.HashCodeAndEqualsPlugin;
import net.bytebuddy.description.method.MethodDescription;
import net.bytebuddy.description.type.TypeDescription;
import net.bytebuddy.description.type.TypeList;
import net.bytebuddy.dynamic.scaffold.MethodGraph;
import net.bytebuddy.implementation.Implementation;
import net.bytebuddy.implementation.bytecode.StackManipulation;
import net.bytebuddy.implementation.bytecode.constant.DefaultValue;
import net.bytebuddy.implementation.bytecode.member.MethodInvocation;
import net.bytebuddy.utility.CompoundList;
import org.objectweb.asm.MethodVisitor;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

An implementation target for redefining a given type while preserving the original methods within the
instrumented type.
 
 Super method calls are merely emulated by this Target in order to preserve Java's super call semantics a user would expect when invoking a super-prefixed method. This means that original methods are either moved to renamed private methods which are never dispatched virtually or they are invoked directly via the INVOKESPECIAL invocation to explicitly forbid a virtual dispatch. /**
 * An implementation target for redefining a given type while preserving the original methods within the
 * instrumented type.
 * <p>&nbsp;</p>
 * Super method calls are merely emulated by this {@link Implementation.Target} in order
 * to preserve Java's super call semantics a user would expect when invoking a {@code super}-prefixed method. This
 * means that original methods are either moved to renamed {@code private} methods which are never dispatched
 * virtually or they are invoked directly via the {@code INVOKESPECIAL} invocation to explicitly forbid a virtual
 * dispatch.
 */
@HashCodeAndEqualsPlugin.Enhance
public class RebaseImplementationTarget extends Implementation.Target.AbstractBase {

    
A mapping of the instrumented type's declared methods by each method's token.
/**
     * A mapping of the instrumented type's declared methods by each method's token.
     */
    private final Map<MethodDescription.SignatureToken, MethodRebaseResolver.Resolution> rebaseableMethods;

    
Creates a rebase implementation target.
Params:
instrumentedType –        The instrumented type.
methodGraph –             A method graph of the instrumented type.
defaultMethodInvocation – The default method invocation mode to apply.
rebaseableMethods –       A mapping of the instrumented type's declared methods by each method's token./**
     * Creates a rebase implementation target.
     *
     * @param instrumentedType        The instrumented type.
     * @param methodGraph             A method graph of the instrumented type.
     * @param defaultMethodInvocation The default method invocation mode to apply.
     * @param rebaseableMethods       A mapping of the instrumented type's declared methods by each method's token.
     */
    protected RebaseImplementationTarget(TypeDescription instrumentedType,
                                         MethodGraph.Linked methodGraph,
                                         DefaultMethodInvocation defaultMethodInvocation,
                                         Map<MethodDescription.SignatureToken, MethodRebaseResolver.Resolution> rebaseableMethods) {
        super(instrumentedType, methodGraph, defaultMethodInvocation);
        this.rebaseableMethods = rebaseableMethods;
    }

    
Creates a new rebase implementation target.
Params:
instrumentedType –     The instrumented type.
methodGraph –          A method graph of the instrumented type.
classFileVersion –     The type's class file version.
methodRebaseResolver – A method rebase resolver to be used when calling a rebased method.
Returns:
An implementation target for the given input./**
     * Creates a new rebase implementation target.
     *
     * @param instrumentedType     The instrumented type.
     * @param methodGraph          A method graph of the instrumented type.
     * @param classFileVersion     The type's class file version.
     * @param methodRebaseResolver A method rebase resolver to be used when calling a rebased method.
     * @return An implementation target for the given input.
     */
    protected static Implementation.Target of(TypeDescription instrumentedType,
                                              MethodGraph.Linked methodGraph,
                                              ClassFileVersion classFileVersion,
                                              MethodRebaseResolver methodRebaseResolver) {
        return new RebaseImplementationTarget(instrumentedType, methodGraph, DefaultMethodInvocation.of(classFileVersion), methodRebaseResolver.asTokenMap());
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    public Implementation.SpecialMethodInvocation invokeSuper(MethodDescription.SignatureToken token) {
        MethodRebaseResolver.Resolution resolution = rebaseableMethods.get(token);
        return resolution == null
                ? invokeSuper(methodGraph.getSuperClassGraph().locate(token))
                : invokeSuper(resolution);
    }

    
Creates a special method invocation for the given node.
Params:
node – The node for which a special method invocation is to be created.
Returns:
A special method invocation for the provided node./**
     * Creates a special method invocation for the given node.
     *
     * @param node The node for which a special method invocation is to be created.
     * @return A special method invocation for the provided node.
     */
    private Implementation.SpecialMethodInvocation invokeSuper(MethodGraph.Node node) {
        return node.getSort().isResolved()
                ? Implementation.SpecialMethodInvocation.Simple.of(node.getRepresentative(), instrumentedType.getSuperClass().asErasure())
                : Implementation.SpecialMethodInvocation.Illegal.INSTANCE;
    }

    
Creates a special method invocation for the given rebase resolution.
Params:
resolution – The resolution for which a special method invocation is to be created.
Returns:
A special method invocation for the provided resolution./**
     * Creates a special method invocation for the given rebase resolution.
     *
     * @param resolution The resolution for which a special method invocation is to be created.
     * @return A special method invocation for the provided resolution.
     */
    private Implementation.SpecialMethodInvocation invokeSuper(MethodRebaseResolver.Resolution resolution) {
        return resolution.isRebased()
                ? RebasedMethodInvocation.of(resolution.getResolvedMethod(), instrumentedType, resolution.getPrependedParameters())
                : Implementation.SpecialMethodInvocation.Simple.of(resolution.getResolvedMethod(), instrumentedType);
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    public TypeDescription getOriginType() {
        return instrumentedType;
    }

    
A SpecialMethodInvocation which invokes a rebased method as given by a MethodRebaseResolver. /**
     * A {@link Implementation.SpecialMethodInvocation} which invokes a rebased method
     * as given by a {@link MethodRebaseResolver}.
     */
    protected static class RebasedMethodInvocation extends Implementation.SpecialMethodInvocation.AbstractBase {

        
The method to invoke via a special method invocation.
/**
         * The method to invoke via a special method invocation.
         */
        private final MethodDescription methodDescription;

        
The instrumented type on which the method should be invoked on.
/**
         * The instrumented type on which the method should be invoked on.
         */
        private final TypeDescription instrumentedType;

        
The stack manipulation to execute in order to invoke the rebased method.
/**
         * The stack manipulation to execute in order to invoke the rebased method.
         */
        private final StackManipulation stackManipulation;

        
Any additional arguments that are to be provided to the rebased method.
/**
         * Any additional arguments that are to be provided to the rebased method.
         */
        private final TypeList prependedParameters;

        
Creates a new rebased method invocation.
Params:
methodDescription –   The method to invoke via a special method invocation.
instrumentedType –    The instrumented type on which the method should be invoked on.
stackManipulation –   The stack manipulation to execute in order to invoke the rebased method.
prependedParameters – Any additional arguments that are to be provided to the rebased method./**
         * Creates a new rebased method invocation.
         *
         * @param methodDescription   The method to invoke via a special method invocation.
         * @param instrumentedType    The instrumented type on which the method should be invoked on.
         * @param stackManipulation   The stack manipulation to execute in order to invoke the rebased method.
         * @param prependedParameters Any additional arguments that are to be provided to the rebased method.
         */
        protected RebasedMethodInvocation(MethodDescription methodDescription,
                                          TypeDescription instrumentedType,
                                          StackManipulation stackManipulation,
                                          TypeList prependedParameters) {
            this.methodDescription = methodDescription;
            this.instrumentedType = instrumentedType;
            this.stackManipulation = stackManipulation;
            this.prependedParameters = prependedParameters;
        }

        
Creates a special method invocation for the given method.
Params:
resolvedMethod –      The rebased method to be invoked.
instrumentedType –    The instrumented type on which the method is to be invoked if it is non-static.
prependedParameters – Any additional arguments that are to be provided to the rebased method.
Returns:
A special method invocation of the rebased method./**
         * Creates a special method invocation for the given method.
         *
         * @param resolvedMethod      The rebased method to be invoked.
         * @param instrumentedType    The instrumented type on which the method is to be invoked if it is non-static.
         * @param prependedParameters Any additional arguments that are to be provided to the rebased method.
         * @return A special method invocation of the rebased method.
         */
        protected static Implementation.SpecialMethodInvocation of(MethodDescription resolvedMethod, TypeDescription instrumentedType, TypeList prependedParameters) {
            StackManipulation stackManipulation = resolvedMethod.isStatic()
                    ? MethodInvocation.invoke(resolvedMethod)
                    : MethodInvocation.invoke(resolvedMethod).special(instrumentedType);
            if (stackManipulation.isValid()) {
                List<StackManipulation> stackManipulations = new ArrayList<StackManipulation>(prependedParameters.size() + 1);
                for (TypeDescription prependedParameter : prependedParameters) {
                    stackManipulations.add(DefaultValue.of(prependedParameter));
                }
                stackManipulations.add(stackManipulation);
                return new RebasedMethodInvocation(resolvedMethod, instrumentedType, new Compound(stackManipulations), prependedParameters);
            } else {
                return Illegal.INSTANCE;
            }
        }

        
{@inheritDoc}
/**
         * {@inheritDoc}
         */
        public MethodDescription getMethodDescription() {
            return methodDescription;
        }

        
{@inheritDoc}
/**
         * {@inheritDoc}
         */
        public TypeDescription getTypeDescription() {
            return instrumentedType;
        }

        
{@inheritDoc}
/**
         * {@inheritDoc}
         */
        public Size apply(MethodVisitor methodVisitor, Implementation.Context implementationContext) {
            return stackManipulation.apply(methodVisitor, implementationContext);
        }

        
{@inheritDoc}
/**
         * {@inheritDoc}
         */
        public Implementation.SpecialMethodInvocation withCheckedCompatibilityTo(MethodDescription.TypeToken token) {
            if (methodDescription.asTypeToken().equals(new MethodDescription.TypeToken(token.getReturnType(),
                    CompoundList.of(token.getParameterTypes(), prependedParameters)))) {
                return this;
            } else {
                return Illegal.INSTANCE;
            }
        }
    }

    
A factory for creating a RebaseImplementationTarget. /**
     * A factory for creating a {@link RebaseImplementationTarget}.
     */
    @HashCodeAndEqualsPlugin.Enhance
    public static class Factory implements Implementation.Target.Factory {

        
The method rebase resolver to use.
/**
         * The method rebase resolver to use.
         */
        private final MethodRebaseResolver methodRebaseResolver;

        
Creates a new factory for a rebase implementation target.
Params:
methodRebaseResolver – The method rebase resolver to use./**
         * Creates a new factory for a rebase implementation target.
         *
         * @param methodRebaseResolver The method rebase resolver to use.
         */
        public Factory(MethodRebaseResolver methodRebaseResolver) {
            this.methodRebaseResolver = methodRebaseResolver;
        }

        
{@inheritDoc}
/**
         * {@inheritDoc}
         */
        public Implementation.Target make(TypeDescription instrumentedType, MethodGraph.Linked methodGraph, ClassFileVersion classFileVersion) {
            return RebaseImplementationTarget.of(instrumentedType, methodGraph, classFileVersion, methodRebaseResolver);
        }
    }
}