/*
 * Copyright (c) 2011, 2019 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package org.glassfish.jersey.server.model;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CancellationException;
import java.util.concurrent.CompletionStage;
import java.util.function.BiConsumer;
import java.util.function.Supplier;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

import javax.ws.rs.ProcessingException;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.container.ContainerResponseFilter;
import javax.ws.rs.container.DynamicFeature;
import javax.ws.rs.container.ResourceInfo;
import javax.ws.rs.core.Configuration;
import javax.ws.rs.core.MultivaluedHashMap;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.Response;
import javax.ws.rs.ext.ReaderInterceptor;
import javax.ws.rs.ext.WriterInterceptor;

import org.glassfish.jersey.internal.inject.AbstractBinder;
import org.glassfish.jersey.internal.inject.InjectionManager;
import org.glassfish.jersey.internal.inject.Injections;
import org.glassfish.jersey.internal.inject.Providers;
import org.glassfish.jersey.model.ContractProvider;
import org.glassfish.jersey.model.NameBound;
import org.glassfish.jersey.model.internal.ComponentBag;
import org.glassfish.jersey.model.internal.RankedComparator;
import org.glassfish.jersey.model.internal.RankedProvider;
import org.glassfish.jersey.process.Inflector;
import org.glassfish.jersey.server.ContainerRequest;
import org.glassfish.jersey.server.ContainerResponse;
import org.glassfish.jersey.server.internal.LocalizationMessages;
import org.glassfish.jersey.server.internal.ProcessingProviders;
import org.glassfish.jersey.server.internal.inject.ConfiguredValidator;
import org.glassfish.jersey.server.internal.process.Endpoint;
import org.glassfish.jersey.server.internal.process.RequestProcessingContext;
import org.glassfish.jersey.server.model.internal.ResourceMethodDispatcherFactory;
import org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory;
import org.glassfish.jersey.server.monitoring.RequestEvent;
import org.glassfish.jersey.server.spi.internal.ResourceMethodDispatcher;
import org.glassfish.jersey.server.spi.internal.ResourceMethodInvocationHandlerProvider;

/**
 * Server-side request-response {@link Inflector inflector} for invoking methods
 * of annotation-based resource classes.
 *
 * @author Marek Potociar
 * @author Martin Matula
 */
public class ResourceMethodInvoker implements Endpoint, ResourceInfo {

    private final ResourceMethod method;
    private final Annotation[] methodAnnotations;
    private final Type invocableResponseType;
    private final boolean canUseInvocableResponseType;
    private final ResourceMethodDispatcher dispatcher;
    private final Method resourceMethod;
    private final Class<?> resourceClass;
    private final List<RankedProvider<ContainerRequestFilter>> requestFilters = new ArrayList<>();
    private final List<RankedProvider<ContainerResponseFilter>> responseFilters = new ArrayList<>();
    private final Iterable<ReaderInterceptor> readerInterceptors;
    private final Iterable<WriterInterceptor> writerInterceptors;

    /**
     * Resource method invoker helper.
     * <p>
     * The builder API provides means for constructing a properly initialized
     * {@link ResourceMethodInvoker resource method invoker} instances.
     */
    public static class Builder {

        private ResourceMethodDispatcherFactory resourceMethodDispatcherFactory;
        private ResourceMethodInvocationHandlerFactory resourceMethodInvocationHandlerFactory;
        private InjectionManager injectionManager;
        private Configuration configuration;
        private Supplier<ConfiguredValidator> configurationValidator;

        /**
         * Set resource method dispatcher factory.
         *
         * @param resourceMethodDispatcherFactory resource method dispatcher factory.
         * @return updated builder.
         */
        public Builder resourceMethodDispatcherFactory(ResourceMethodDispatcherFactory resourceMethodDispatcherFactory) {
            this.resourceMethodDispatcherFactory = resourceMethodDispatcherFactory;
            return this;
        }

        /**
         * Set resource method invocation handler factory.
         *
         * @param resourceMethodInvocationHandlerFactory resource method invocation handler factory.
         * @return updated builder.
         */
        public Builder resourceMethodInvocationHandlerFactory(
                ResourceMethodInvocationHandlerFactory resourceMethodInvocationHandlerFactory) {
            this.resourceMethodInvocationHandlerFactory = resourceMethodInvocationHandlerFactory;
            return this;
        }

        /**
         * Set runtime DI injection manager.
         *
         * @param injectionManager DI injection manager.
         * @return updated builder.
         */
        public Builder injectionManager(InjectionManager injectionManager) {
            this.injectionManager = injectionManager;
            return this;
        }

        /**
         * Set global configuration.
         *
         * @param configuration global configuration.
         * @return updated builder.
         */
        public Builder configuration(Configuration configuration) {
            this.configuration = configuration;
            return this;
        }

        /**
         * Set global configuration validator.
         *
         * @param configurationValidator configuration validator.
         * @return updated builder.
         */
        public Builder configurationValidator(Supplier<ConfiguredValidator> configurationValidator) {
            this.configurationValidator = configurationValidator;
            return this;
        }

        /**
         * Build a new resource method invoker instance.
         *
         * @param method              resource method model.
         * @param processingProviders Processing providers.
         * @return new resource method invoker instance.
         */
        public ResourceMethodInvoker build(ResourceMethod method, ProcessingProviders processingProviders) {
            if (resourceMethodDispatcherFactory == null) {
                throw new NullPointerException("ResourceMethodDispatcherFactory is not set.");
            }
            if (resourceMethodInvocationHandlerFactory == null) {
                throw new NullPointerException("ResourceMethodInvocationHandlerFactory is not set.");
            }
            if (injectionManager == null) {
                throw new NullPointerException("DI injection manager is not set.");
            }
            if (configuration == null) {
                throw new NullPointerException("Configuration is not set.");
            }
            if (configurationValidator == null) {
                throw new NullPointerException("Configuration validator is not set.");
            }

            return new ResourceMethodInvoker(
                    resourceMethodDispatcherFactory,
                    resourceMethodInvocationHandlerFactory,
                    method,
                    processingProviders, injectionManager,
                    configuration,
                    configurationValidator.get());
        }
    }

    private ResourceMethodInvoker(
            final ResourceMethodDispatcher.Provider dispatcherProvider,
            final ResourceMethodInvocationHandlerProvider invocationHandlerProvider,
            final ResourceMethod method,
            final ProcessingProviders processingProviders,
            InjectionManager injectionManager,
            final Configuration globalConfig,
            final ConfiguredValidator validator) {


        this.method = method;
        final Invocable invocable = method.getInvocable();
        this.dispatcher = dispatcherProvider.create(invocable,
                invocationHandlerProvider.create(invocable), validator);

        this.resourceMethod = invocable.getHandlingMethod();
        this.resourceClass = invocable.getHandler().getHandlerClass();

        // Configure dynamic features.
        final ResourceMethodConfig config = new ResourceMethodConfig(globalConfig.getProperties());
        for (final DynamicFeature dynamicFeature : processingProviders.getDynamicFeatures()) {
            dynamicFeature.configure(this, config);
        }

        final ComponentBag componentBag = config.getComponentBag();
        final List<Object> providers = new ArrayList<>(
                componentBag.getInstances(ComponentBag.excludeMetaProviders(injectionManager)));

        // Get instances of providers.
        final Set<Class<?>> providerClasses = componentBag.getClasses(ComponentBag.excludeMetaProviders(injectionManager));
        if (!providerClasses.isEmpty()) {
            injectionManager = Injections.createInjectionManager(injectionManager);
            injectionManager.register(new AbstractBinder() {
                @Override
                protected void configure() {
                    bind(config).to(Configuration.class);
                }
            });

            for (final Class<?> providerClass : providerClasses) {
                providers.add(injectionManager.createAndInitialize(providerClass));
            }
        }

        final List<RankedProvider<ReaderInterceptor>> _readerInterceptors = new LinkedList<>();
        final List<RankedProvider<WriterInterceptor>> _writerInterceptors = new LinkedList<>();
        final List<RankedProvider<ContainerRequestFilter>> _requestFilters = new LinkedList<>();
        final List<RankedProvider<ContainerResponseFilter>> _responseFilters = new LinkedList<>();

        for (final Object provider : providers) {
            final ContractProvider model = componentBag.getModel(provider.getClass());
            final Set<Class<?>> contracts = model.getContracts();

            if (contracts.contains(WriterInterceptor.class)) {
                _writerInterceptors.add(
                        new RankedProvider<>(
                                (WriterInterceptor) provider,
                                model.getPriority(WriterInterceptor.class)));
            }

            if (contracts.contains(ReaderInterceptor.class)) {
                _readerInterceptors.add(
                        new RankedProvider<>(
                                (ReaderInterceptor) provider,
                                model.getPriority(ReaderInterceptor.class)));
            }

            if (contracts.contains(ContainerRequestFilter.class)) {
                _requestFilters.add(
                        new RankedProvider<>(
                                (ContainerRequestFilter) provider,
                                model.getPriority(ContainerRequestFilter.class)));
            }

            if (contracts.contains(ContainerResponseFilter.class)) {
                _responseFilters.add(
                        new RankedProvider<>(
                                (ContainerResponseFilter) provider,
                                model.getPriority(ContainerResponseFilter.class)));
            }
        }

        _readerInterceptors.addAll(
                StreamSupport.stream(processingProviders.getGlobalReaderInterceptors().spliterator(), false)
                             .collect(Collectors.toList()));
        _writerInterceptors.addAll(
                StreamSupport.stream(processingProviders.getGlobalWriterInterceptors().spliterator(), false)
                             .collect(Collectors.toList()));

        if (resourceMethod != null) {
            addNameBoundFiltersAndInterceptors(
                    processingProviders,
                    _requestFilters, _responseFilters, _readerInterceptors, _writerInterceptors,
                    method);
        }

        this.readerInterceptors = Collections.unmodifiableList(StreamSupport.stream(Providers.sortRankedProviders(
                new RankedComparator<>(), _readerInterceptors).spliterator(), false).collect(Collectors.toList()));
        this.writerInterceptors = Collections.unmodifiableList(StreamSupport.stream(Providers.sortRankedProviders(
                new RankedComparator<>(), _writerInterceptors).spliterator(), false).collect(Collectors.toList()));
        this.requestFilters.addAll(_requestFilters);
        this.responseFilters.addAll(_responseFilters);

        // pre-compute & cache invocation properties
        this.methodAnnotations = invocable.getHandlingMethod().getDeclaredAnnotations();
        this.invocableResponseType = invocable.getResponseType();
        this.canUseInvocableResponseType = invocableResponseType != null
                && Void.TYPE != invocableResponseType
                && Void.class != invocableResponseType
                && // Do NOT change the entity type for Response or it's subclasses.
                !((invocableResponseType instanceof Class) && Response.class.isAssignableFrom((Class) invocableResponseType));

    }

    private <T> void addNameBoundProviders(
            final Collection<RankedProvider<T>> targetCollection,
            final NameBound nameBound,
            final MultivaluedMap<Class<? extends Annotation>, RankedProvider<T>> nameBoundProviders,
            final MultivaluedMap<RankedProvider<T>, Class<? extends Annotation>> nameBoundProvidersInverse) {

        final MultivaluedMap<RankedProvider<T>, Class<? extends Annotation>> foundBindingsMap = new MultivaluedHashMap<>();
        for (final Class<? extends Annotation> nameBinding : nameBound.getNameBindings()) {
            final Iterable<RankedProvider<T>> providers = nameBoundProviders.get(nameBinding);
            if (providers != null) {
                for (final RankedProvider<T> provider : providers) {
                    foundBindingsMap.add(provider, nameBinding);
                }
            }
        }

        for (final Map.Entry<RankedProvider<T>, List<Class<? extends Annotation>>> entry : foundBindingsMap.entrySet()) {
            final RankedProvider<T> provider = entry.getKey();
            final List<Class<? extends Annotation>> foundBindings = entry.getValue();
            final List<Class<? extends Annotation>> providerBindings = nameBoundProvidersInverse.get(provider);
            if (foundBindings.size() == providerBindings.size()) {
                targetCollection.add(provider);
            }
        }
    }

    private void addNameBoundFiltersAndInterceptors(
            final ProcessingProviders processingProviders,
            final Collection<RankedProvider<ContainerRequestFilter>> targetRequestFilters,
            final Collection<RankedProvider<ContainerResponseFilter>> targetResponseFilters,
            final Collection<RankedProvider<ReaderInterceptor>> targetReaderInterceptors,
            final Collection<RankedProvider<WriterInterceptor>> targetWriterInterceptors,
            final NameBound nameBound
    ) {
        addNameBoundProviders(targetRequestFilters, nameBound, processingProviders.getNameBoundRequestFilters(),
                processingProviders.getNameBoundRequestFiltersInverse());
        addNameBoundProviders(targetResponseFilters, nameBound, processingProviders.getNameBoundResponseFilters(),
                processingProviders.getNameBoundResponseFiltersInverse());
        addNameBoundProviders(targetReaderInterceptors, nameBound, processingProviders.getNameBoundReaderInterceptors(),
                processingProviders.getNameBoundReaderInterceptorsInverse());
        addNameBoundProviders(targetWriterInterceptors, nameBound, processingProviders.getNameBoundWriterInterceptors(),
                processingProviders.getNameBoundWriterInterceptorsInverse());
    }


    @Override
    public Method getResourceMethod() {
        return resourceMethod;
    }

    @Override
    public Class<?> getResourceClass() {
        return resourceClass;
    }

    @Override
    @SuppressWarnings("unchecked")
    public ContainerResponse apply(final RequestProcessingContext processingContext) {
        final ContainerRequest request = processingContext.request();
        final Object resource = processingContext.routingContext().peekMatchedResource();

        if (method.isSuspendDeclared() || method.isManagedAsyncDeclared() || method.isSse()) {
            if (!processingContext.asyncContext().suspend()) {
                throw new ProcessingException(LocalizationMessages.ERROR_SUSPENDING_ASYNC_REQUEST());
            }
        }

        if (method.isManagedAsyncDeclared()) {
            processingContext.asyncContext().invokeManaged(() -> {
                final Response response = invoke(processingContext, resource);
                if (method.isSuspendDeclared()) {
                    // we ignore any response returned from a method that injects AsyncResponse
                    return null;
                }
                return response;
            });
            return null; // return null on current thread
        } else {
            // TODO replace with processing context factory method.
            Response response = invoke(processingContext, resource);

            // we don't care about the response when SseEventSink is injected - it will be sent asynchronously.
            if (method.isSse()) {
                return null;
            }

            if (response.hasEntity()) {
                Object entityFuture = response.getEntity();
                if (entityFuture instanceof CompletionStage) {
                    CompletionStage completionStage = ((CompletionStage) entityFuture);

                    // suspend - we know that this feature is not done, see AbstractJavaResourceMethodDispatcher#invoke
                    if (!processingContext.asyncContext().suspend()) {
                        throw new ProcessingException(LocalizationMessages.ERROR_SUSPENDING_ASYNC_REQUEST());
                    }

                    // wait for a response
                    completionStage.whenComplete(whenComplete(processingContext));

                    return null; // return null on the current thread
                }
            }

            return new ContainerResponse(request, response);
        }
    }

    private BiConsumer whenComplete(RequestProcessingContext processingContext) {
        return (entity, exception) -> {

            if (exception != null) {
                if (exception instanceof CancellationException) {
                    processingContext.asyncContext().resume(Response.status(Response.Status.SERVICE_UNAVAILABLE).build());
                } else {
                    processingContext.asyncContext().resume(((Throwable) exception));
                }
            } else {
                processingContext.asyncContext().resume(entity);
            }
        };
    }

    private Response invoke(final RequestProcessingContext context, final Object resource) {

        Response jaxrsResponse;
        context.triggerEvent(RequestEvent.Type.RESOURCE_METHOD_START);

        context.push(response -> {
            // Need to check whether the response is null or mapped from exception. In these cases we don't want to modify
            // response with resource method metadata.
            if (response == null
                    || response.isMappedFromException()) {
                return response;
            }

            final Annotation[] entityAnn = response.getEntityAnnotations();
            if (methodAnnotations.length > 0) {
                if (entityAnn.length == 0) {
                    response.setEntityAnnotations(methodAnnotations);
                } else {
                    final Annotation[] mergedAnn = Arrays.copyOf(methodAnnotations,
                            methodAnnotations.length + entityAnn.length);
                    System.arraycopy(entityAnn, 0, mergedAnn, methodAnnotations.length, entityAnn.length);
                    response.setEntityAnnotations(mergedAnn);
                }
            }

            if (canUseInvocableResponseType
                    && response.hasEntity()
                    && !(response.getEntityType() instanceof ParameterizedType)) {
                response.setEntityType(invocableResponseType);
            }

            return response;
        });

        try {
            jaxrsResponse = dispatcher.dispatch(resource, context.request());
        } finally {
            context.triggerEvent(RequestEvent.Type.RESOURCE_METHOD_FINISHED);
        }

        if (jaxrsResponse == null) {
            jaxrsResponse = Response.noContent().build();
        }

        return jaxrsResponse;
    }

    /**
     * Get all bound request filters applicable to the {@link #getResourceMethod() resource method}
     * wrapped by this invoker.
     *
     * @return All bound (dynamically or by name) request filters applicable to the {@link #getResourceMethod() resource
     * method}.
     */
    public Iterable<RankedProvider<ContainerRequestFilter>> getRequestFilters() {
        return requestFilters;
    }

    /**
     * Get all bound response filters applicable to the {@link #getResourceMethod() resource method}
     * wrapped by this invoker.
     *
     * @return All bound (dynamically or by name) response filters applicable to the {@link #getResourceMethod() resource
     * method}.
     */
    public Iterable<RankedProvider<ContainerResponseFilter>> getResponseFilters() {
        return responseFilters;
    }

    /**
     * Get all reader interceptors applicable to the {@link #getResourceMethod() resource method}
     * wrapped by this invoker.
     *
     * @return All reader interceptors applicable to the {@link #getResourceMethod() resource method}.
     */
    public Iterable<WriterInterceptor> getWriterInterceptors() {
        return writerInterceptors;
    }

    /**
     * Get all writer interceptors applicable to the {@link #getResourceMethod() resource method}
     * wrapped by this invoker.
     *
     * @return All writer interceptors applicable to the {@link #getResourceMethod() resource method}.
     */
    public Iterable<ReaderInterceptor> getReaderInterceptors() {
        return readerInterceptors;
    }

    @Override
    public String toString() {
        return method.getInvocable().getHandlingMethod().toString();
    }
}
