/*
 * Copyright (c) 2018, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.svm.hosted.snippets;

import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Constructor;
import java.lang.reflect.Executable;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.graalvm.compiler.api.replacements.SnippetReflectionProvider;
import org.graalvm.compiler.nodes.ConstantNode;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderContext;
import org.graalvm.compiler.nodes.graphbuilderconf.InvocationPlugin;
import org.graalvm.compiler.nodes.graphbuilderconf.InvocationPlugin.Receiver;
import org.graalvm.compiler.nodes.graphbuilderconf.InvocationPlugins;
import org.graalvm.compiler.nodes.graphbuilderconf.InvocationPlugins.Registration;
import org.graalvm.compiler.options.Option;
import org.graalvm.nativeimage.ImageSingletons;

import com.oracle.graal.pointsto.infrastructure.OriginalClassProvider;
import com.oracle.svm.core.annotate.Delete;
import com.oracle.svm.core.option.HostedOptionKey;
import com.oracle.svm.hosted.ExceptionSynthesizer;
import com.oracle.svm.hosted.ImageClassLoader;
import com.oracle.svm.hosted.SVMHost;
import com.oracle.svm.hosted.c.GraalAccess;
import com.oracle.svm.hosted.phases.SubstrateClassInitializationPlugin;
import com.oracle.svm.hosted.substitute.AnnotationSubstitutionProcessor;
import com.oracle.svm.hosted.substitute.DeletedElementException;

import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.JavaKind;
import jdk.vm.ci.meta.MetaAccessProvider;
import jdk.vm.ci.meta.ResolvedJavaMethod;
import jdk.vm.ci.meta.ResolvedJavaType;

public class ReflectionPlugins {

    public static class ReflectionPluginRegistry extends IntrinsificationPluginRegistry {
        public static AutoCloseable startThreadLocalRegistry() {
            return ImageSingletons.lookup(ReflectionPluginRegistry.class).startThreadLocalReflectionRegistry();
        }
    }

    static class Options {
        @Option(help = "Enable trace logging for reflection plugins.")//
        static final HostedOptionKey<Boolean> ReflectionPluginTracing = new HostedOptionKey<>(false);
    }

    public static void registerInvocationPlugins(ImageClassLoader imageClassLoader, SnippetReflectionProvider snippetReflection, AnnotationSubstitutionProcessor annotationSubstitutions,
                    InvocationPlugins plugins, SVMHost hostVM, boolean analysis, boolean hosted) {
        /*
         * Initialize the registry if we are during analysis. If hosted is false, i.e., we are
         * analyzing the static initializers, then we always intrinsify, so don't need a registry.
         */
        if (hosted && analysis) {
            if (!ImageSingletons.contains(ReflectionPluginRegistry.class)) {
                ImageSingletons.add(ReflectionPluginRegistry.class, new ReflectionPluginRegistry());
            }
        }

        registerClassPlugins(imageClassLoader, snippetReflection, annotationSubstitutions, plugins, hostVM, analysis, hosted);
    }

    private static void registerClassPlugins(ImageClassLoader imageClassLoader, SnippetReflectionProvider snippetReflection, AnnotationSubstitutionProcessor annotationSubstitutions,
                    InvocationPlugins plugins, SVMHost hostVM, boolean analysis, boolean hosted) {
        Registration r = new Registration(plugins, Class.class);

        r.register1("forName", String.class, new InvocationPlugin() {
            @Override
            public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver, ValueNode name) {
                return processForName(b, hostVM, targetMethod, name, ConstantNode.forBoolean(true), imageClassLoader, snippetReflection, analysis, hosted);
            }
        });

        r.register3("forName", String.class, boolean.class, ClassLoader.class, new InvocationPlugin() {
            @Override
            public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver, ValueNode name, ValueNode initialize, ValueNode classLoader) {
                return processForName(b, hostVM, targetMethod, name, initialize, imageClassLoader, snippetReflection, analysis, hosted);
            }
        });

        r.register2("getDeclaredField", Receiver.class, String.class, new InvocationPlugin() {
            @Override
            public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver, ValueNode name) {
                return processGetField(b, targetMethod, receiver, name, snippetReflection, true, analysis, hosted);
            }
        });

        r.register2("getField", Receiver.class, String.class, new InvocationPlugin() {
            @Override
            public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver, ValueNode name) {
                return processGetField(b, targetMethod, receiver, name, snippetReflection, false, analysis, hosted);
            }
        });

        r.register3("getDeclaredMethod", Receiver.class, String.class, Class[].class, new InvocationPlugin() {
            @Override
            public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver, ValueNode name, ValueNode parameterTypes) {
                return processGetMethod(b, targetMethod, receiver, name, parameterTypes, annotationSubstitutions, snippetReflection, true, analysis, hosted);
            }
        });

        r.register3("getMethod", Receiver.class, String.class, Class[].class, new InvocationPlugin() {
            @Override
            public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver, ValueNode name, ValueNode parameterTypes) {
                return processGetMethod(b, targetMethod, receiver, name, parameterTypes, annotationSubstitutions, snippetReflection, false, analysis, hosted);
            }
        });

        r.register2("getDeclaredConstructor", Receiver.class, Class[].class, new InvocationPlugin() {
            @Override
            public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver, ValueNode parameterTypes) {
                return processGetConstructor(b, targetMethod, receiver, parameterTypes, snippetReflection, annotationSubstitutions, true, analysis, hosted);
            }
        });

        r.register2("getConstructor", Receiver.class, Class[].class, new InvocationPlugin() {
            @Override
            public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver, ValueNode parameterTypes) {
                return processGetConstructor(b, targetMethod, receiver, parameterTypes, snippetReflection, annotationSubstitutions, false, analysis, hosted);
            }
        });
    }

    private static boolean processForName(GraphBuilderContext b, SVMHost host, ResolvedJavaMethod targetMethod, ValueNode name, ValueNode initialize,
                    ImageClassLoader imageClassLoader, SnippetReflectionProvider snippetReflection, boolean analysis, boolean hosted) {
        if (name.isConstant() && initialize.isConstant()) {
            String className = snippetReflection.asObject(String.class, name.asJavaConstant());
            Class<?> clazz = imageClassLoader.findClass(className).get();
            if (clazz == null) {
                return throwException(b, targetMethod, analysis, hosted, className, ClassNotFoundException.class, className);
            } else {
                Class<?> intrinsic = getIntrinsic(analysis, hosted, b, clazz);
                if (intrinsic == null) {
                    return false;
                }
                ResolvedJavaType type = b.getMetaAccess().lookupJavaType(clazz);
                JavaConstant hub = b.getConstantReflection().asJavaClass(type);
                pushConstant(b, targetMethod, hub, className);
                boolean doInitialize = initialize.asJavaConstant().asInt() != 0;
                if (doInitialize && host.getClassInitializationSupport().shouldInitializeAtRuntime(clazz)) {
                    SubstrateClassInitializationPlugin.emitEnsureClassInitialized(b, hub);
                }
                return true;
            }
        }
        return false;
    }

    private static boolean processGetField(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver, ValueNode name,
                    SnippetReflectionProvider snippetReflection, boolean declared, boolean analysis, boolean hosted) {
        if (receiver.isConstant() && name.isConstant()) {
            Class<?> clazz = getReceiverClass(b, receiver);
            String fieldName = snippetReflection.asObject(String.class, name.asJavaConstant());

            String target = clazz.getTypeName() + "." + fieldName;
            try {
                Field field = declared ? clazz.getDeclaredField(fieldName) : clazz.getField(fieldName);
                return pushConstant(b, targetMethod, snippetReflection, analysis, hosted, field, target);
            } catch (NoSuchFieldException | LinkageError e) {
                return throwException(b, targetMethod, analysis, hosted, target, e.getClass(), e.getMessage());
            }
        }
        return false;
    }

    private static boolean processGetMethod(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver, ValueNode name,
                    ValueNode parameterTypes, AnnotationSubstitutionProcessor annotationSubstitutions, SnippetReflectionProvider snippetReflection, boolean declared, boolean analysis,
                    boolean hosted) {
        if (receiver.isConstant() && name.isConstant()) {
            Class<?>[] paramTypes = SubstrateGraphBuilderPlugins.extractClassArray(annotationSubstitutions, snippetReflection, parameterTypes, true);

            if (paramTypes != null) {
                Class<?> clazz = getReceiverClass(b, receiver);
                String methodName = snippetReflection.asObject(String.class, name.asJavaConstant());

                String target = clazz.getTypeName() + "." + methodName + "(" + Stream.of(paramTypes).map(Class::getTypeName).collect(Collectors.joining(", ")) + ")";
                try {
                    Method method = declared ? clazz.getDeclaredMethod(methodName, paramTypes) : clazz.getMethod(methodName, paramTypes);
                    return pushConstant(b, targetMethod, snippetReflection, analysis, hosted, method, target);
                } catch (NoSuchMethodException | LinkageError e) {
                    return throwException(b, targetMethod, analysis, hosted, target, e.getClass(), e.getMessage());
                }
            }
        }
        return false;
    }

    private static boolean processGetConstructor(GraphBuilderContext b, ResolvedJavaMethod targetMethod,
                    Receiver receiver, ValueNode parameterTypes,
                    SnippetReflectionProvider snippetReflection, AnnotationSubstitutionProcessor annotationSubstitutions, boolean declared,
                    boolean analysis, boolean hosted) {
        if (receiver.isConstant()) {
            Class<?>[] paramTypes = SubstrateGraphBuilderPlugins.extractClassArray(annotationSubstitutions, snippetReflection, parameterTypes, true);

            if (paramTypes != null) {
                Class<?> clazz = getReceiverClass(b, receiver);

                String target = clazz.getTypeName() + ".<init>(" + Stream.of(paramTypes).map(Class::getTypeName).collect(Collectors.joining(", ")) + ")";
                try {
                    Constructor<?> constructor = declared ? clazz.getDeclaredConstructor(paramTypes) : clazz.getConstructor(paramTypes);
                    return pushConstant(b, targetMethod, snippetReflection, analysis, hosted, constructor, target);
                } catch (NoSuchMethodException | LinkageError e) {
                    return throwException(b, targetMethod, analysis, hosted, target, e.getClass(), e.getMessage());
                }
            }
        }
        return false;
    }

    
Get the Class object corresponding to the receiver of the reflective call. If the class is
substituted we want the original class, and not the substitution. The reflective call to
getMethod()/getConstructor()/getField() will yield the original member, which will be
intrinsified, and subsequent phases are responsible for getting the right substitution
method/constructor/field.
/**
     * Get the Class object corresponding to the receiver of the reflective call. If the class is
     * substituted we want the original class, and not the substitution. The reflective call to
     * getMethod()/getConstructor()/getField() will yield the original member, which will be
     * intrinsified, and subsequent phases are responsible for getting the right substitution
     * method/constructor/field.
     */
    private static Class<?> getReceiverClass(GraphBuilderContext b, Receiver receiver) {
        ResolvedJavaType javaType = b.getConstantReflection().asJavaType(receiver.get().asJavaConstant());
        return OriginalClassProvider.getJavaClass(GraalAccess.getOriginalSnippetReflection(), javaType);
    }

    
This method checks if the element should be intrinsified and returns the cached intrinsic
element if found. Caching intrinsic elements during analysis and reusing the same element
during compilation is important! For each call to Class.getMethod/Class.getField the JDK
returns a copy of the original object. Many of the reflection metadata fields are lazily
initialized, therefore the copy is partial. During analysis we use the
ReflectionMetadataFeature::replacer to ensure that the reflection metadata is eagerly
initialized. Therefore, we want to intrinsify the same, eagerly initialized object during
compilation, not a lossy copy of it.
/**
     * This method checks if the element should be intrinsified and returns the cached intrinsic
     * element if found. Caching intrinsic elements during analysis and reusing the same element
     * during compilation is important! For each call to Class.getMethod/Class.getField the JDK
     * returns a copy of the original object. Many of the reflection metadata fields are lazily
     * initialized, therefore the copy is partial. During analysis we use the
     * ReflectionMetadataFeature::replacer to ensure that the reflection metadata is eagerly
     * initialized. Therefore, we want to intrinsify the same, eagerly initialized object during
     * compilation, not a lossy copy of it.
     */
    private static <T> T getIntrinsic(boolean analysis, boolean hosted, GraphBuilderContext context, T element) {
        if (!hosted) {
            /* We are analyzing the static initializers and should always intrinsify. */
            return element;
        }
        /*
         * We don't intrinsify if bci is not unique.
         */
        if (context.bciCanBeDuplicated()) {
            return null;
        }
        if (analysis) {
            if (isDeleted(element, context.getMetaAccess())) {
                /*
                 * Should not intrinsify. Will fail during the reflective lookup at
                 * runtime. @Delete-ed elements are ignored by the reflection plugins regardless of
                 * the value of ReportUnsupportedElementsAtRuntime.
                 */
                return null;
            }

            /* We are during analysis, we should intrinsify and cache the intrinsified object. */
            ImageSingletons.lookup(ReflectionPluginRegistry.class).add(context.getCallingContext(), element);
        }
        /* We are during compilation, we only intrinsify if intrinsified during analysis. */
        return ImageSingletons.lookup(ReflectionPluginRegistry.class).get(context.getCallingContext());
    }

    private static <T> boolean isDeleted(T element, MetaAccessProvider metaAccess) {
        AnnotatedElement annotated = null;
        try {
            if (element instanceof Executable) {
                annotated = metaAccess.lookupJavaMethod((Executable) element);
            } else if (element instanceof Field) {
                annotated = metaAccess.lookupJavaField((Field) element);
            }
        } catch (DeletedElementException ex) {
            /*
             * If ReportUnsupportedElementsAtRuntime is *not* set looking up a @Delete-ed element
             * will result in a DeletedElementException.
             */
            return true;
        }
        /*
         * If ReportUnsupportedElementsAtRuntime is set looking up a @Delete-ed element will return
         * a substitution method that has the @Delete annotation.
         */
        if (annotated != null && annotated.isAnnotationPresent(Delete.class)) {
            return true;
        }
        return false;
    }

    private static <T> boolean pushConstant(GraphBuilderContext b, ResolvedJavaMethod targetMethod, SnippetReflectionProvider snippetReflection,
                    boolean analysis, boolean hosted, T element, String targetElement) {
        T intrinsic = getIntrinsic(analysis, hosted, b, element);
        if (intrinsic == null) {
            return false;
        }
        pushConstant(b, targetMethod, snippetReflection.forObject(intrinsic), targetElement);
        return true;
    }

    private static void pushConstant(GraphBuilderContext b, ResolvedJavaMethod reflectionMethod, JavaConstant constant, String targetElement) {
        b.addPush(JavaKind.Object, ConstantNode.forConstant(constant, b.getMetaAccess(), b.getGraph()));
        traceConstant(b.getMethod(), reflectionMethod, targetElement);
    }

    private static boolean throwException(GraphBuilderContext b, ResolvedJavaMethod reflectionMethod, boolean analysis, boolean hosted, String targetElement,
                    Class<? extends Throwable> exceptionClass, String originalMessage) {
        /* Get the exception throwing method that has a message parameter. */
        Method exceptionMethod = ExceptionSynthesizer.throwExceptionMethod(exceptionClass, String.class);
        Method intrinsic = getIntrinsic(analysis, hosted, b, exceptionMethod);
        if (intrinsic == null) {
            return false;
        }
        throwException(b, reflectionMethod, targetElement, exceptionMethod, originalMessage);
        return true;
    }

    private static void throwException(GraphBuilderContext b, ResolvedJavaMethod reflectionMethod, String targetElement, Method exceptionMethod, String originalMessage) {
        String message = originalMessage + ". This exception was synthesized during native image building from a call to " + reflectionMethod.format("%H.%n(%p)") +
                        " with constant arguments.";
        ExceptionSynthesizer.throwException(b, exceptionMethod, message);
        traceException(b.getMethod(), reflectionMethod, targetElement, exceptionMethod);
    }

    private static void traceConstant(ResolvedJavaMethod contextMethod, ResolvedJavaMethod reflectionMethod, String targetElement) {
        if (Options.ReflectionPluginTracing.getValue()) {
            System.out.println("Call to " + reflectionMethod.format("%H.%n(%p)") + " reached in " + contextMethod.format("%H.%n(%p)") +
                            " for target " + targetElement + " was reduced to a constant.");
        }
    }

    private static void traceException(ResolvedJavaMethod contextMethod, ResolvedJavaMethod reflectionMethod, String targetElement, Method exceptionMethod) {
        if (Options.ReflectionPluginTracing.getValue()) {
            String exception = exceptionMethod.getExceptionTypes()[0].getName();
            System.out.println("Call to " + reflectionMethod.format("%H.%n(%p)") + " reached in " + contextMethod.format("%H.%n(%p)") +
                            " for target " + targetElement + " was reduced to a \"throw new " + exception + "(...)\"");
        }
    }

}