/*
 * Copyright 2017 the original author or authors.
 *
 * 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 org.gradle.workers.internal;

import org.gradle.api.NonNullApi;
import org.gradle.api.internal.ClassPathRegistry;
import org.gradle.api.internal.CollectionCallbackActionDecorator;
import org.gradle.api.internal.DefaultClassPathProvider;
import org.gradle.api.internal.DefaultClassPathRegistry;
import org.gradle.api.internal.MutationGuards;
import org.gradle.api.internal.classpath.ModuleRegistry;
import org.gradle.api.internal.collections.DefaultDomainObjectCollectionFactory;
import org.gradle.api.internal.collections.DomainObjectCollectionFactory;
import org.gradle.api.internal.file.FileCollectionFactory;
import org.gradle.api.internal.file.FileResolver;
import org.gradle.api.internal.file.archive.DecompressionCoordinator;
import org.gradle.api.internal.file.archive.DefaultDecompressionCoordinator;
import org.gradle.api.internal.project.IsolatedAntBuilder;
import org.gradle.api.internal.project.antbuilder.DefaultIsolatedAntBuilder;
import org.gradle.api.internal.provider.DefaultProviderFactory;
import org.gradle.api.internal.resources.DefaultResourceHandler;
import org.gradle.api.model.ObjectFactory;
import org.gradle.api.provider.ProviderFactory;
import org.gradle.api.resources.ReadableResource;
import org.gradle.api.resources.ResourceHandler;
import org.gradle.api.resources.TextResourceFactory;
import org.gradle.cache.UnscopedCacheBuilderFactory;
import org.gradle.cache.internal.scopes.DefaultBuildTreeScopedCacheBuilderFactory;
import org.gradle.cache.scopes.BuildTreeScopedCacheBuilderFactory;
import org.gradle.initialization.LegacyTypesSupport;
import org.gradle.internal.classloader.ClassLoaderFactory;
import org.gradle.internal.classpath.ClassPath;
import org.gradle.internal.hash.ClassLoaderHierarchyHasher;
import org.gradle.internal.hash.FileHasher;
import org.gradle.internal.hash.HashCode;
import org.gradle.internal.instantiation.InstantiatorFactory;
import org.gradle.internal.isolation.IsolatableFactory;
import org.gradle.internal.reflect.Instantiator;
import org.gradle.internal.service.CloseableServiceRegistry;
import org.gradle.internal.service.Provides;
import org.gradle.internal.service.ServiceRegistrationProvider;
import org.gradle.internal.service.ServiceRegistry;
import org.gradle.internal.service.ServiceRegistryBuilder;
import org.gradle.internal.service.scopes.WorkerSharedBuildSessionScopeServices;
import org.gradle.internal.service.scopes.WorkerSharedGlobalScopeServices;
import org.gradle.internal.service.scopes.WorkerSharedProjectScopeServices;
import org.gradle.internal.service.scopes.WorkerSharedUserHomeScopeServices;
import org.gradle.internal.state.ManagedFactoryRegistry;
import org.gradle.process.internal.ExecFactory;
import org.gradle.process.internal.worker.RequestHandler;
import org.gradle.process.internal.worker.request.RequestArgumentSerializers;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.inject.Inject;
import java.io.File;

public class WorkerDaemonServer implements RequestHandler<TransportableActionExecutionSpec, DefaultWorkResult> {
    private final ServiceRegistry internalServices;
    private final LegacyTypesSupport legacyTypesSupport;
    private final ActionExecutionSpecFactory actionExecutionSpecFactory;
    private final InstantiatorFactory instantiatorFactory;
    private ClassLoader workerClassLoader;

    @Inject
    public WorkerDaemonServer(ServiceRegistry parentServices, RequestArgumentSerializers argumentSerializers) {
        this.internalServices = createWorkerDaemonServices(parentServices);
        this.legacyTypesSupport = internalServices.get(LegacyTypesSupport.class);
        this.actionExecutionSpecFactory = internalServices.get(ActionExecutionSpecFactory.class);
        this.instantiatorFactory = internalServices.get(InstantiatorFactory.class);
        argumentSerializers.register(TransportableActionExecutionSpec.class, new TransportableActionExecutionSpecSerializer());
    }

    static ServiceRegistry createWorkerDaemonServices(ServiceRegistry parent) {
        return ServiceRegistryBuilder.builder()
            .displayName("worker daemon services")
            .parent(parent)
            .provider(new WorkerSharedGlobalScopeServices(ClassPath.EMPTY))
            .provider(new WorkerDaemonServices())
            .provider(new WorkerSharedBuildSessionScopeServices())
            .build();
    }

    @Override
    public DefaultWorkResult run(TransportableActionExecutionSpec spec) {
        try {
            try (CloseableServiceRegistry internalServices = WorkerProjectServices.create(this.internalServices, spec.getBaseDir(), spec.getProjectCacheDir())) {
                RequestHandler<TransportableActionExecutionSpec, DefaultWorkResult> worker = getIsolatedClassloaderWorker(spec.getClassLoaderStructure(), internalServices);
                return worker.run(spec);
            }
        } catch (Throwable t) {
            return new DefaultWorkResult(true, t);
        }
    }

    private RequestHandler<TransportableActionExecutionSpec, DefaultWorkResult> getIsolatedClassloaderWorker(ClassLoaderStructure classLoaderStructure, ServiceRegistry workServices) {
        if (classLoaderStructure instanceof FlatClassLoaderStructure) {
            return new FlatClassLoaderWorker(this.getClass().getClassLoader(), workServices, actionExecutionSpecFactory, instantiatorFactory);
        } else {
            return new IsolatedClassloaderWorker(getWorkerClassLoader(classLoaderStructure), workServices, actionExecutionSpecFactory, instantiatorFactory, true);
        }
    }

    private ClassLoader getWorkerClassLoader(ClassLoaderStructure classLoaderStructure) {
        if (workerClassLoader == null) {
            this.workerClassLoader = IsolatedClassloaderWorker.createIsolatedWorkerClassloader(classLoaderStructure, this.getClass().getClassLoader(), legacyTypesSupport);
        }
        return workerClassLoader;
    }

    @Override
    public String toString() {
        return "WorkerDaemonServer{}";
    }

    private static class WorkerDaemonServices extends WorkerSharedUserHomeScopeServices {

        // TODO:configuration-cache - deprecate workers access to ProviderFactory?
        @Provides
        ProviderFactory createProviderFactory() {
            return new DefaultProviderFactory();
        }

        @Provides
        IsolatableSerializerRegistry createIsolatableSerializerRegistry(ClassLoaderHierarchyHasher classLoaderHierarchyHasher, ManagedFactoryRegistry managedFactoryRegistry) {
            return new IsolatableSerializerRegistry(classLoaderHierarchyHasher, managedFactoryRegistry);
        }

        @Provides
        ActionExecutionSpecFactory createActionExecutionSpecFactory(IsolatableFactory isolatableFactory, IsolatableSerializerRegistry serializerRegistry) {
            return new DefaultActionExecutionSpecFactory(isolatableFactory, serializerRegistry);
        }

        @Provides
        ClassLoaderHierarchyHasher createClassLoaderHierarchyHasher() {
            // Return a dummy implementation of this as creating a real hasher drags ~20 more services
            // along with it, and a hasher isn't actually needed on the worker process side at the moment.
            return new ClassLoaderHierarchyHasher() {
                @Nullable
                @Override
                public HashCode getClassLoaderHash(@Nonnull ClassLoader classLoader) {
                    throw new UnsupportedOperationException();
                }
            };
        }

        @Provides
        DomainObjectCollectionFactory createDomainObjectCollectionFactory(InstantiatorFactory instantiatorFactory, ServiceRegistry services) {
            return new DefaultDomainObjectCollectionFactory(instantiatorFactory, services, CollectionCallbackActionDecorator.NOOP, MutationGuards.identity());
        }

        @Provides
        ClassPathRegistry createClassPathRegistry(ModuleRegistry moduleRegistry) {
            return new DefaultClassPathRegistry(new DefaultClassPathProvider(moduleRegistry));
        }

        @Provides
        IsolatedAntBuilder createIsolatedAntBuilder(ModuleRegistry moduleRegistry, ClassPathRegistry classPathRegistry, ClassLoaderFactory classLoaderFactory) {
            return new DefaultIsolatedAntBuilder(classPathRegistry, classLoaderFactory, moduleRegistry);
        }
    }

    /**
     * This is not correct!
     *
     * These services are normally available in the build session scope, not the project scope.
     * However, workers do not observe the same lifecycle as the build and do not stop or recreate build session services between builds.
     * This works around that by recreating the build session scope services for every request.
     */
    @NonNullApi
    static class WorkerBuildSessionScopeWorkaroundServices implements ServiceRegistrationProvider {
        private final File projectCacheDir;

        WorkerBuildSessionScopeWorkaroundServices(File projectCacheDir) {
            this.projectCacheDir = projectCacheDir;
        }

        @Provides
        protected BuildTreeScopedCacheBuilderFactory createBuildTreeScopedCache(UnscopedCacheBuilderFactory unscopedCacheBuilderFactory) {
            return new DefaultBuildTreeScopedCacheBuilderFactory(projectCacheDir, unscopedCacheBuilderFactory);
        }

        @Provides
        protected DecompressionCoordinator createDecompressionCoordinator(BuildTreeScopedCacheBuilderFactory cacheBuilderFactory) {
            return new DefaultDecompressionCoordinator(cacheBuilderFactory);
        }
    }

    static class WorkerProjectServices implements ServiceRegistrationProvider {

        public static CloseableServiceRegistry create(ServiceRegistry parent, File baseDir, File projectCacheDir) {
            return ServiceRegistryBuilder.builder()
                .displayName("worker request services for " + baseDir.getAbsolutePath())
                .parent(parent)
                .provider(new WorkerProjectServices())
                .provider(new WorkerSharedProjectScopeServices(baseDir))
                .provider(new WorkerBuildSessionScopeWorkaroundServices(projectCacheDir))
                .build();
        }

        @Provides
        protected Instantiator createInstantiator(InstantiatorFactory instantiatorFactory, ServiceRegistry workerProjectScopeServices) {
            return instantiatorFactory.decorateLenient(workerProjectScopeServices);
        }

        @Provides
        protected ExecFactory createExecFactory(ExecFactory execFactory, FileResolver fileResolver, FileCollectionFactory fileCollectionFactory, Instantiator instantiator, ObjectFactory objectFactory) {
            return execFactory.forContext()
                .withFileResolver(fileResolver)
                .withFileCollectionFactory(fileCollectionFactory)
                .withInstantiator(instantiator)
                .withObjectFactory(objectFactory)
                .build();
        }

        @Provides
        protected DefaultResourceHandler.Factory createResourceHandlerFactory() {
            // We use a dummy implementation of this as creating a real resource handler would require us to add
            // an additional jar to the worker runtime startup and a resource handler isn't actually needed in
            // the worker process.
            ResourceHandler resourceHandler = new ResourceHandler() {
                @Override
                public ReadableResource gzip(Object path) {
                    throw new UnsupportedOperationException();
                }

                @Override
                public ReadableResource bzip2(Object path) {
                    throw new UnsupportedOperationException();
                }

                @Override
                public TextResourceFactory getText() {
                    throw new UnsupportedOperationException();
                }
            };

            return fileOperations -> resourceHandler;
        }

        @Provides
        FileHasher createFileHasher() {
            // Return a dummy implementation of this as creating a real file hasher drags numerous other services
            // along with it, and a file hasher isn't actually needed on the worker process side at the moment.
            return new FileHasher() {
                @Override
                public HashCode hash(File file) {
                    throw new UnsupportedOperationException();
                }

                @Override
                public HashCode hash(File file, long length, long lastModified) {
                    throw new UnsupportedOperationException();
                }
            };
        }
    }
}
