package org.apache.archiva.metadata.repository.storage.maven2;

/*
 * 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.
 */

import org.apache.archiva.checksum.ChecksumAlgorithm;
import org.apache.archiva.checksum.ChecksummedFile;
import org.apache.archiva.common.Try;
import org.apache.archiva.common.utils.VersionUtil;
import org.apache.archiva.filter.Filter;
import org.apache.archiva.maven2.metadata.MavenMetadataReader;
import org.apache.archiva.metadata.model.ArtifactMetadata;
import org.apache.archiva.metadata.model.ProjectMetadata;
import org.apache.archiva.metadata.model.ProjectVersionMetadata;
import org.apache.archiva.metadata.model.facets.RepositoryProblemFacet;
import org.apache.archiva.metadata.repository.storage.*;
import org.apache.archiva.model.ArchivaRepositoryMetadata;
import org.apache.archiva.model.ArtifactReference;
import org.apache.archiva.model.SnapshotVersion;
import org.apache.archiva.policies.ProxyDownloadException;
import org.apache.archiva.proxy.ProxyRegistry;
import org.apache.archiva.proxy.maven.WagonFactory;
import org.apache.archiva.proxy.model.NetworkProxy;
import org.apache.archiva.proxy.model.ProxyConnector;
import org.apache.archiva.proxy.model.RepositoryProxyHandler;
import org.apache.archiva.repository.*;
import org.apache.archiva.repository.content.PathParser;
import org.apache.archiva.repository.maven2.MavenSystemManager;
import org.apache.archiva.repository.storage.StorageAsset;
import org.apache.archiva.xml.XMLException;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.maven.model.*;
import org.apache.maven.model.building.*;
import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;
import javax.inject.Inject;
import javax.inject.Named;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.Reader;
import java.nio.channels.Channels;
import java.nio.charset.Charset;
import java.nio.file.NoSuchFileException;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.util.*;
import java.util.function.Predicate;
import java.util.stream.Collectors;

// import java.io.FileNotFoundException;

/**
 * <p>
 * Maven 2 repository format storage implementation. This class currently takes parameters to indicate the repository to
 * deal with rather than being instantiated per-repository.
 * FIXME: instantiate one per repository and allocate permanently from a factory (which can be obtained within the session).
 * </p>
 * <p>
 * The session is passed in as an argument to obtain any necessary resources, rather than the class being instantiated
 * within the session in the context of a single managed repository's resolution needs.
 * </p>
 */
@Service("repositoryStorage#maven2")
public class Maven2RepositoryStorage
        implements RepositoryStorage {

    private static final Logger LOGGER = LoggerFactory.getLogger(Maven2RepositoryStorage.class);

    private ModelBuilder builder;

    @Inject
    RepositoryRegistry repositoryRegistry;

    @Inject
    @Named("repositoryPathTranslator#maven2")
    private RepositoryPathTranslator pathTranslator;

    @Inject
    private WagonFactory wagonFactory;

    @Inject
    private ApplicationContext applicationContext;

    @Inject
    @Named("pathParser#default")
    private PathParser pathParser;

    @Inject
    private ProxyRegistry proxyRegistry;

    @Inject
    private MavenSystemManager mavenSystemManager;

    private static final String METADATA_FILENAME_START = "maven-metadata";

    private static final String METADATA_FILENAME = METADATA_FILENAME_START + ".xml";

    // This array must be lexically sorted
    private static final String[] IGNORED_FILES = {METADATA_FILENAME, "resolver-status.properties"};

    private static final MavenXpp3Reader MAVEN_XPP_3_READER = new MavenXpp3Reader();


    @PostConstruct
    public void initialize() {
        builder = new DefaultModelBuilderFactory().newInstance();

    }

    @Override
    public ProjectMetadata readProjectMetadata(String repoId, String namespace, String projectId) {
        // TODO: could natively implement the "shared model" concept from the browse action to avoid needing it there?
        return null;
    }

    @Override
    public ProjectVersionMetadata readProjectVersionMetadata(ReadMetadataRequest readMetadataRequest)
            throws RepositoryStorageMetadataNotFoundException, RepositoryStorageMetadataInvalidException,
            RepositoryStorageRuntimeException {

        ManagedRepository managedRepository = repositoryRegistry.getManagedRepository(readMetadataRequest.getRepositoryId());
        boolean isReleases = managedRepository.getActiveReleaseSchemes().contains(ReleaseScheme.RELEASE);
        boolean isSnapshots = managedRepository.getActiveReleaseSchemes().contains(ReleaseScheme.SNAPSHOT);
        String artifactVersion = readMetadataRequest.getProjectVersion();
        // olamy: in case of browsing via the ui we can mix repos (parent of a SNAPSHOT can come from release repo)
        if (!readMetadataRequest.isBrowsingRequest()) {
            if (VersionUtil.isSnapshot(artifactVersion)) {
                // skygo trying to improve speed by honoring managed configuration MRM-1658
                if (isReleases && !isSnapshots) {
                    throw new RepositoryStorageRuntimeException("lookforsnaponreleaseonly",
                            "managed repo is configured for release only");
                }
            } else {
                if (!isReleases && isSnapshots) {
                    throw new RepositoryStorageRuntimeException("lookforsreleaseonsneponly",
                            "managed repo is configured for snapshot only");
                }
            }
        }
        StorageAsset basedir = managedRepository.getAsset("");
        if (VersionUtil.isSnapshot(artifactVersion)) {
            StorageAsset metadataFile = pathTranslator.toFile(basedir, readMetadataRequest.getNamespace(),
                    readMetadataRequest.getProjectId(), artifactVersion,
                    METADATA_FILENAME);
            try {
                ArchivaRepositoryMetadata metadata = MavenMetadataReader.read(metadataFile);

                // re-adjust to timestamp if present, otherwise retain the original -SNAPSHOT filename
                SnapshotVersion snapshotVersion = metadata.getSnapshotVersion();
                if (snapshotVersion != null) {
                    artifactVersion =
                            artifactVersion.substring(0, artifactVersion.length() - 8); // remove SNAPSHOT from end
                    artifactVersion =
                            artifactVersion + snapshotVersion.getTimestamp() + "-" + snapshotVersion.getBuildNumber();
                }
            } catch (XMLException | IOException e) {
                // unable to parse metadata - LOGGER it, and continue with the version as the original SNAPSHOT version
                LOGGER.warn("Invalid metadata: {} - {}", metadataFile, e.getMessage());
            }
        }

        // TODO: won't work well with some other layouts, might need to convert artifact parts to ID by path translator
        String id = readMetadataRequest.getProjectId() + "-" + artifactVersion + ".pom";
        StorageAsset file =
                pathTranslator.toFile(basedir, readMetadataRequest.getNamespace(), readMetadataRequest.getProjectId(),
                        readMetadataRequest.getProjectVersion(), id);

        if (!file.exists()) {
            // metadata could not be resolved
            throw new RepositoryStorageMetadataNotFoundException(
                    "The artifact's POM file '" + file.getPath() + "' was missing");
        }

        // TODO: this is a workaround until we can properly resolve using proxies as well - this doesn't cache
        //       anything locally!
        List<RemoteRepository> remoteRepositories = new ArrayList<>();
        Map<String, NetworkProxy> networkProxies = new HashMap<>();

        Map<String, List<ProxyConnector>> proxyConnectorsMap = proxyRegistry.getProxyConnectorAsMap();
        List<ProxyConnector> proxyConnectors = proxyConnectorsMap.get(readMetadataRequest.getRepositoryId());
        if (proxyConnectors != null) {
            for (ProxyConnector proxyConnector : proxyConnectors) {
                RemoteRepository remoteRepoConfig =
                        repositoryRegistry.getRemoteRepository(proxyConnector.getTargetRepository().getId());

                if (remoteRepoConfig != null) {
                    remoteRepositories.add(remoteRepoConfig);

                    NetworkProxy networkProxyConfig =
                            proxyRegistry.getNetworkProxy(proxyConnector.getProxyId());

                    if (networkProxyConfig != null) {
                        // key/value: remote repo ID/proxy info
                        networkProxies.put(proxyConnector.getTargetRepository().getId(), networkProxyConfig);
                    }
                }
            }
        }

        // That's a browsing request so we can a mix of SNAPSHOT and release artifacts (especially with snapshots which
        // can have released parent pom
        if (readMetadataRequest.isBrowsingRequest()) {
            remoteRepositories.addAll(repositoryRegistry.getRemoteRepositories());
        }

        ModelBuildingRequest req =
                new DefaultModelBuildingRequest().setProcessPlugins(false).setPomFile(file.getFilePath().toFile()).setTwoPhaseBuilding(
                        false).setValidationLevel(ModelBuildingRequest.VALIDATION_LEVEL_MINIMAL);

        //MRM-1607. olamy this will resolve jdk profiles on the current running archiva jvm
        req.setSystemProperties(System.getProperties());

        // MRM-1411
        req.setModelResolver(
                new RepositoryModelResolver(managedRepository, pathTranslator, wagonFactory, remoteRepositories,
                        networkProxies, managedRepository, mavenSystemManager));

        Model model;
        try {
            model = builder.build(req).getEffectiveModel();
        } catch (ModelBuildingException e) {
            String msg = "The artifact's POM file '" + file + "' was invalid: " + e.getMessage();

            List<ModelProblem> modelProblems = e.getProblems();
            for (ModelProblem problem : modelProblems) {
                // MRM-1411, related to MRM-1335
                // this means that the problem was that the parent wasn't resolved!
                // olamy really hackhish but fail with java profile so use error message
                // || ( StringUtils.startsWith( problem.getMessage(), "Failed to determine Java version for profile" ) )
                // but setTwoPhaseBuilding(true) fix that
                if (((problem.getException() instanceof FileNotFoundException
                        || problem.getException() instanceof NoSuchFileException
                ) && e.getModelId() != null &&
                        !e.getModelId().equals(problem.getModelId()))) {
                    LOGGER.warn("The artifact's parent POM file '{}' cannot be resolved. "
                            + "Using defaults for project version metadata..", file);

                    ProjectVersionMetadata metadata = new ProjectVersionMetadata();
                    metadata.setId(readMetadataRequest.getProjectVersion());

                    MavenProjectFacet facet = new MavenProjectFacet();
                    facet.setGroupId(readMetadataRequest.getNamespace());
                    facet.setArtifactId(readMetadataRequest.getProjectId());
                    facet.setPackaging("jar");
                    metadata.addFacet(facet);

                    String errMsg =
                            "Error in resolving artifact's parent POM file. " + (problem.getException() == null
                                    ? problem.getMessage()
                                    : problem.getException().getMessage());
                    RepositoryProblemFacet repoProblemFacet = new RepositoryProblemFacet();
                    repoProblemFacet.setRepositoryId(readMetadataRequest.getRepositoryId());
                    repoProblemFacet.setId(readMetadataRequest.getRepositoryId());
                    repoProblemFacet.setMessage(errMsg);
                    repoProblemFacet.setProblem(errMsg);
                    repoProblemFacet.setProject(readMetadataRequest.getProjectId());
                    repoProblemFacet.setVersion(readMetadataRequest.getProjectVersion());
                    repoProblemFacet.setNamespace(readMetadataRequest.getNamespace());

                    metadata.addFacet(repoProblemFacet);

                    return metadata;
                }
            }

            throw new RepositoryStorageMetadataInvalidException("invalid-pom", msg, e);
        }

        // Check if the POM is in the correct location
        boolean correctGroupId = readMetadataRequest.getNamespace().equals(model.getGroupId());
        boolean correctArtifactId = readMetadataRequest.getProjectId().equals(model.getArtifactId());
        boolean correctVersion = readMetadataRequest.getProjectVersion().equals(model.getVersion());
        if (!correctGroupId || !correctArtifactId || !correctVersion) {
            StringBuilder message = new StringBuilder("Incorrect POM coordinates in '" + file + "':");
            if (!correctGroupId) {
                message.append("\nIncorrect group ID: ").append(model.getGroupId());
            }
            if (!correctArtifactId) {
                message.append("\nIncorrect artifact ID: ").append(model.getArtifactId());
            }
            if (!correctVersion) {
                message.append("\nIncorrect version: ").append(model.getVersion());
            }

            throw new RepositoryStorageMetadataInvalidException("mislocated-pom", message.toString());
        }

        ProjectVersionMetadata metadata = new ProjectVersionMetadata();
        metadata.setCiManagement(convertCiManagement(model.getCiManagement()));
        metadata.setDescription(model.getDescription());
        metadata.setId(readMetadataRequest.getProjectVersion());
        metadata.setIssueManagement(convertIssueManagement(model.getIssueManagement()));
        metadata.setLicenses(convertLicenses(model.getLicenses()));
        metadata.setMailingLists(convertMailingLists(model.getMailingLists()));
        metadata.setDependencies(convertDependencies(model.getDependencies()));
        metadata.setName(model.getName());
        metadata.setOrganization(convertOrganization(model.getOrganization()));
        metadata.setScm(convertScm(model.getScm()));
        metadata.setUrl(model.getUrl());
        metadata.setProperties(model.getProperties());

        MavenProjectFacet facet = new MavenProjectFacet();
        facet.setGroupId(model.getGroupId() != null ? model.getGroupId() : model.getParent().getGroupId());
        facet.setArtifactId(model.getArtifactId());
        facet.setPackaging(model.getPackaging());
        if (model.getParent() != null) {
            MavenProjectParent parent = new MavenProjectParent();
            parent.setGroupId(model.getParent().getGroupId());
            parent.setArtifactId(model.getParent().getArtifactId());
            parent.setVersion(model.getParent().getVersion());
            facet.setParent(parent);
        }
        metadata.addFacet(facet);

        return metadata;


    }

    public void setWagonFactory(WagonFactory wagonFactory) {
        this.wagonFactory = wagonFactory;
    }

    private List<org.apache.archiva.metadata.model.Dependency> convertDependencies(List<Dependency> dependencies) {
        List<org.apache.archiva.metadata.model.Dependency> l = new ArrayList<>();
        for (Dependency dependency : dependencies) {
            org.apache.archiva.metadata.model.Dependency newDependency =
                    new org.apache.archiva.metadata.model.Dependency();
            newDependency.setArtifactId(dependency.getArtifactId());
            newDependency.setClassifier(dependency.getClassifier());
            newDependency.setNamespace(dependency.getGroupId());
            newDependency.setOptional(dependency.isOptional());
            newDependency.setScope(dependency.getScope());
            newDependency.setSystemPath(dependency.getSystemPath());
            newDependency.setType(dependency.getType());
            newDependency.setVersion(dependency.getVersion());
            l.add(newDependency);
        }
        return l;
    }

    private org.apache.archiva.metadata.model.Scm convertScm(Scm scm) {
        org.apache.archiva.metadata.model.Scm newScm = null;
        if (scm != null) {
            newScm = new org.apache.archiva.metadata.model.Scm();
            newScm.setConnection(scm.getConnection());
            newScm.setDeveloperConnection(scm.getDeveloperConnection());
            newScm.setUrl(scm.getUrl());
        }
        return newScm;
    }

    private org.apache.archiva.metadata.model.Organization convertOrganization(Organization organization) {
        org.apache.archiva.metadata.model.Organization org = null;
        if (organization != null) {
            org = new org.apache.archiva.metadata.model.Organization();
            org.setName(organization.getName());
            org.setUrl(organization.getUrl());
        }
        return org;
    }

    private List<org.apache.archiva.metadata.model.License> convertLicenses(List<License> licenses) {
        List<org.apache.archiva.metadata.model.License> l = new ArrayList<>();
        for (License license : licenses) {
            org.apache.archiva.metadata.model.License newLicense = new org.apache.archiva.metadata.model.License();
            newLicense.setName(license.getName());
            newLicense.setUrl(license.getUrl());
            l.add(newLicense);
        }
        return l;
    }

    private List<org.apache.archiva.metadata.model.MailingList> convertMailingLists(List<MailingList> mailingLists) {
        List<org.apache.archiva.metadata.model.MailingList> l = new ArrayList<>();
        for (MailingList mailingList : mailingLists) {
            org.apache.archiva.metadata.model.MailingList newMailingList =
                    new org.apache.archiva.metadata.model.MailingList();
            newMailingList.setName(mailingList.getName());
            newMailingList.setMainArchiveUrl(mailingList.getArchive());
            newMailingList.setPostAddress(mailingList.getPost());
            newMailingList.setSubscribeAddress(mailingList.getSubscribe());
            newMailingList.setUnsubscribeAddress(mailingList.getUnsubscribe());
            newMailingList.setOtherArchives(mailingList.getOtherArchives());
            l.add(newMailingList);
        }
        return l;
    }

    private org.apache.archiva.metadata.model.IssueManagement convertIssueManagement(IssueManagement issueManagement) {
        org.apache.archiva.metadata.model.IssueManagement im = null;
        if (issueManagement != null) {
            im = new org.apache.archiva.metadata.model.IssueManagement();
            im.setSystem(issueManagement.getSystem());
            im.setUrl(issueManagement.getUrl());
        }
        return im;
    }

    private org.apache.archiva.metadata.model.CiManagement convertCiManagement(CiManagement ciManagement) {
        org.apache.archiva.metadata.model.CiManagement ci = null;
        if (ciManagement != null) {
            ci = new org.apache.archiva.metadata.model.CiManagement();
            ci.setSystem(ciManagement.getSystem());
            ci.setUrl(ciManagement.getUrl());
        }
        return ci;
    }

    @Override
    public Collection<String> listRootNamespaces(String repoId, Filter<String> filter)
            throws RepositoryStorageRuntimeException {
        StorageAsset dir = getRepositoryBasedir(repoId);

        return getSortedFiles(dir, filter);
    }

    private static Collection<String> getSortedFiles(StorageAsset dir, Filter<String> filter) {

        final Predicate<StorageAsset> dFilter = new DirectoryFilter(filter);
        return dir.list().stream().filter(f -> f.isContainer())
                .filter(dFilter)
                .map(path -> path.getName().toString())
                .sorted().collect(Collectors.toList());

    }

    private StorageAsset getRepositoryBasedir(String repoId)
            throws RepositoryStorageRuntimeException {
        ManagedRepository repositoryConfiguration = repositoryRegistry.getManagedRepository(repoId);

        return repositoryConfiguration.getAsset("");
    }

    @Override
    public Collection<String> listNamespaces(String repoId, String namespace, Filter<String> filter)
            throws RepositoryStorageRuntimeException {
        StorageAsset dir = pathTranslator.toFile(getRepositoryBasedir(repoId), namespace);
        if (!(dir.exists()) && !dir.isContainer()) {
            return Collections.emptyList();
        }
        // scan all the directories which are potential namespaces. Any directories known to be projects are excluded
        Predicate<StorageAsset> dFilter = new DirectoryFilter(filter);
        return dir.list().stream().filter(dFilter).filter(path -> !isProject(path, filter)).map(path -> path.getName().toString())
                .sorted().collect(Collectors.toList());
    }

    @Override
    public Collection<String> listProjects(String repoId, String namespace, Filter<String> filter)
            throws RepositoryStorageRuntimeException {
        StorageAsset dir = pathTranslator.toFile(getRepositoryBasedir(repoId), namespace);
        if (!(dir.exists() && dir.isContainer())) {
            return Collections.emptyList();
        }
        // scan all directories in the namespace, and only include those that are known to be projects
        final Predicate<StorageAsset> dFilter = new DirectoryFilter(filter);
        return dir.list().stream().filter(dFilter).filter(path -> isProject(path, filter)).map(path -> path.getName().toString())
                .sorted().collect(Collectors.toList());

    }

    @Override
    public Collection<String> listProjectVersions(String repoId, String namespace, String projectId,
                                                  Filter<String> filter)
            throws RepositoryStorageRuntimeException {
        StorageAsset dir = pathTranslator.toFile(getRepositoryBasedir(repoId), namespace, projectId);
        if (!(dir.exists() && dir.isContainer())) {
            return Collections.emptyList();
        }

        // all directories in a project directory can be considered a version
        return getSortedFiles(dir, filter);
    }

    @Override
    public Collection<ArtifactMetadata> readArtifactsMetadata(ReadMetadataRequest readMetadataRequest)
            throws RepositoryStorageRuntimeException {
        StorageAsset dir = pathTranslator.toFile(getRepositoryBasedir(readMetadataRequest.getRepositoryId()),
                readMetadataRequest.getNamespace(), readMetadataRequest.getProjectId(),
                readMetadataRequest.getProjectVersion());
        if (!(dir.exists() && dir.isContainer())) {
            return Collections.emptyList();
        }

        // all files that are not metadata and not a checksum / signature are considered artifacts
        final Predicate<StorageAsset> dFilter = new ArtifactDirectoryFilter(readMetadataRequest.getFilter());
        // Returns a map TRUE -> (success values), FALSE -> (Exceptions)
        Map<Boolean, List<Try<ArtifactMetadata>>> result = dir.list().stream().filter(dFilter).map(path -> {
                    try {
                        return Try.success(getArtifactFromFile(readMetadataRequest.getRepositoryId(), readMetadataRequest.getNamespace(),
                                readMetadataRequest.getProjectId(), readMetadataRequest.getProjectVersion(),
                                path));
                    } catch (Exception e) {
                        LOGGER.debug("Could not create metadata for {}:  {}", path, e.getMessage(), e);
                        return Try.<ArtifactMetadata>failure(e);
                    }
                }
        ).collect(Collectors.groupingBy(Try::isSuccess));
        if (result.containsKey(Boolean.FALSE) && result.get(Boolean.FALSE).size() > 0 && (!result.containsKey(Boolean.TRUE) || result.get(Boolean.TRUE).size() == 0)) {
            LOGGER.error("Could not get artifact metadata. Directory: {}. Number of errors {}.", dir, result.get(Boolean.FALSE).size());
            Try<ArtifactMetadata> failure = result.get(Boolean.FALSE).get(0);
            LOGGER.error("Sample exception {}", failure.getError().getMessage(), failure.getError());
            throw new RepositoryStorageRuntimeException(readMetadataRequest.getRepositoryId(), "Could not retrieve metadata of the files");
        } else {
            if (!result.containsKey(Boolean.TRUE) || result.get(Boolean.TRUE) == null) {
                return Collections.emptyList();
            }
            return result.get(Boolean.TRUE).stream().map(tr -> tr.get()).collect(Collectors.toList());
        }

    }

    @Override
    public ArtifactMetadata readArtifactMetadataFromPath(String repoId, String path)
            throws RepositoryStorageRuntimeException {
        ArtifactMetadata metadata = pathTranslator.getArtifactForPath(repoId, path);

        try {
            populateArtifactMetadataFromFile(metadata, getRepositoryBasedir(repoId).resolve(path));
        } catch (IOException e) {
            throw new RepositoryStorageRuntimeException(repoId, "Error during metadata retrieval of " + path + " :" + e.getMessage(), e);
        }

        return metadata;
    }

    private ArtifactMetadata getArtifactFromFile(String repoId, String namespace, String projectId,
                                                 String projectVersion, StorageAsset file) throws IOException {
        ArtifactMetadata metadata =
                pathTranslator.getArtifactFromId(repoId, namespace, projectId, projectVersion, file.getName());

        populateArtifactMetadataFromFile(metadata, file);

        return metadata;
    }

    @Override
    public void applyServerSideRelocation(ManagedRepository managedRepository, ArtifactReference artifact)
            throws ProxyDownloadException {
        if ("pom".equals(artifact.getType())) {
            return;
        }

        // Build the artifact POM reference
        ArtifactReference pomReference = new ArtifactReference();
        pomReference.setGroupId(artifact.getGroupId());
        pomReference.setArtifactId(artifact.getArtifactId());
        pomReference.setVersion(artifact.getVersion());
        pomReference.setType("pom");

        RepositoryType repositoryType = managedRepository.getType();
        if (!proxyRegistry.hasHandler(repositoryType)) {
            throw new ProxyDownloadException("No proxy handler found for repository type " + repositoryType, new HashMap<>());
        }

        RepositoryProxyHandler proxyHandler = proxyRegistry.getHandler(repositoryType).get(0);

        // Get the artifact POM from proxied repositories if needed
        proxyHandler.fetchFromProxies(managedRepository, pomReference);

        // Open and read the POM from the managed repo
        StorageAsset pom = managedRepository.getContent().toFile(pomReference);

        if (!pom.exists()) {
            return;
        }

        try {
            // MavenXpp3Reader leaves the file open, so we need to close it ourselves.

            Model model;
            try (Reader reader = Channels.newReader(pom.getReadChannel(), Charset.defaultCharset().name())) {
                model = MAVEN_XPP_3_READER.read(reader);
            }

            DistributionManagement dist = model.getDistributionManagement();
            if (dist != null) {
                Relocation relocation = dist.getRelocation();
                if (relocation != null) {
                    // artifact is relocated : update the repositoryPath
                    if (relocation.getGroupId() != null) {
                        artifact.setGroupId(relocation.getGroupId());
                    }
                    if (relocation.getArtifactId() != null) {
                        artifact.setArtifactId(relocation.getArtifactId());
                    }
                    if (relocation.getVersion() != null) {
                        artifact.setVersion(relocation.getVersion());
                    }
                }
            }
        } catch (IOException e) {
            // Unable to read POM : ignore.
        } catch (XmlPullParserException e) {
            // Invalid POM : ignore
        }
    }


    @Override
    public String getFilePath(String requestPath, org.apache.archiva.repository.ManagedRepository managedRepository) {
        // managedRepository can be null
        // extract artifact reference from url
        // groupId:artifactId:version:packaging:classifier
        //org/apache/archiva/archiva-checksum/1.4-M4-SNAPSHOT/archiva-checksum-1.4-M4-SNAPSHOT.jar
        String logicalResource = null;
        String requestPathInfo = StringUtils.defaultString(requestPath);

        //remove prefix ie /repository/blah becomes /blah
        requestPathInfo = removePrefix(requestPathInfo);

        // Remove prefixing slash as the repository id doesn't contain it;
        if (requestPathInfo.startsWith("/")) {
            requestPathInfo = requestPathInfo.substring(1);
        }

        int slash = requestPathInfo.indexOf('/');
        if (slash > 0) {
            logicalResource = requestPathInfo.substring(slash);

            if (logicalResource.endsWith("/..")) {
                logicalResource += "/";
            }

            if (logicalResource != null && logicalResource.startsWith("//")) {
                logicalResource = logicalResource.substring(1);
            }

            if (logicalResource == null) {
                logicalResource = "/";
            }
        } else {
            logicalResource = "/";
        }
        return logicalResource;

    }

    @Override
    public String getFilePathWithVersion(final String requestPath, ManagedRepositoryContent managedRepositoryContent)
            throws RelocationException, XMLException, IOException {

        if (StringUtils.endsWith(requestPath, METADATA_FILENAME)) {
            return getFilePath(requestPath, managedRepositoryContent.getRepository());
        }

        String filePath = getFilePath(requestPath, managedRepositoryContent.getRepository());

        ArtifactReference artifactReference = null;
        try {
            artifactReference = pathParser.toArtifactReference(filePath);
        } catch (LayoutException e) {
            return filePath;
        }

        if (StringUtils.endsWith(artifactReference.getVersion(), VersionUtil.SNAPSHOT)) {
            // read maven metadata to get last timestamp
            StorageAsset metadataDir = managedRepositoryContent.getRepository().getAsset(filePath).getParent();
            if (!metadataDir.exists()) {
                return filePath;
            }
            StorageAsset metadataFile = metadataDir.resolve(METADATA_FILENAME);
            if (!metadataFile.exists()) {
                return filePath;
            }
            ArchivaRepositoryMetadata archivaRepositoryMetadata = MavenMetadataReader.read(metadataFile);
            int buildNumber = archivaRepositoryMetadata.getSnapshotVersion().getBuildNumber();
            String timestamp = archivaRepositoryMetadata.getSnapshotVersion().getTimestamp();

            // MRM-1846
            if (buildNumber < 1 && timestamp == null) {
                return filePath;
            }

            // org/apache/archiva/archiva-checksum/1.4-M4-SNAPSHOT/archiva-checksum-1.4-M4-SNAPSHOT.jar
            // ->  archiva-checksum-1.4-M4-20130425.081822-1.jar

            filePath = StringUtils.replace(filePath, //
                    artifactReference.getArtifactId() //
                            + "-" + artifactReference.getVersion(), //
                    artifactReference.getArtifactId() //
                            + "-" + StringUtils.remove(artifactReference.getVersion(),
                            "-" + VersionUtil.SNAPSHOT) //
                            + "-" + timestamp //
                            + "-" + buildNumber);

            throw new RelocationException("/repository/" + managedRepositoryContent.getRepository().getId() +
                    (StringUtils.startsWith(filePath, "/") ? "" : "/") + filePath,
                    RelocationException.RelocationType.TEMPORARY);

        }

        return filePath;
    }

    //-----------------------------
    // internal
    //-----------------------------

    /**
     * FIXME remove
     *
     * @param href
     * @return
     */
    private static String removePrefix(final String href) {
        String[] parts = StringUtils.split(href, '/');
        parts = (String[]) ArrayUtils.subarray(parts, 1, parts.length);
        if (parts == null || parts.length == 0) {
            return "/";
        }

        String joinedString = StringUtils.join(parts, '/');
        if (href.endsWith("/")) {
            joinedString = joinedString + "/";
        }

        return joinedString;
    }

    private static void populateArtifactMetadataFromFile(ArtifactMetadata metadata, StorageAsset file) throws IOException {
        metadata.setWhenGathered(ZonedDateTime.now(ZoneId.of("GMT")));
        metadata.setFileLastModified(file.getModificationTime().toEpochMilli());
        ChecksummedFile checksummedFile = new ChecksummedFile(file.getFilePath());
        try {
            metadata.setMd5(checksummedFile.calculateChecksum(ChecksumAlgorithm.MD5));
        } catch (IOException e) {
            LOGGER.error("Unable to checksum file {}: {},MD5", file, e.getMessage());
        }
        try {
            metadata.setSha1(checksummedFile.calculateChecksum(ChecksumAlgorithm.SHA1));
        } catch (IOException e) {
            LOGGER.error("Unable to checksum file {}: {},SHA1", file, e.getMessage());
        }
        metadata.setSize(file.getSize());
    }

    private boolean isProject(StorageAsset dir, Filter<String> filter) {
        // scan directories for a valid project version subdirectory, meaning this must be a project directory
        final Predicate<StorageAsset> dFilter = new DirectoryFilter(filter);
        boolean projFound = dir.list().stream().filter(dFilter)
                .anyMatch(path -> isProjectVersion(path));
        if (projFound) {
            return true;
        }

        // if a metadata file is present, check if this is the "artifactId" directory, marking it as a project
        ArchivaRepositoryMetadata metadata = readMetadata(dir);
        if (metadata != null && dir.getName().toString().equals(metadata.getArtifactId())) {
            return true;
        }

        return false;
    }

    private boolean isProjectVersion(StorageAsset dir) {
        final String artifactId = dir.getParent().getName();
        final String projectVersion = dir.getName();

        // check if there is a POM artifact file to ensure it is a version directory

        Predicate<StorageAsset> filter;
        if (VersionUtil.isSnapshot(projectVersion)) {
            filter = new PomFilenameFilter(artifactId, projectVersion);
        } else {
            final String pomFile = artifactId + "-" + projectVersion + ".pom";
            filter = new PomFileFilter(pomFile);
        }
        if (dir.list().stream().filter(f -> !f.isContainer()).anyMatch(filter)) {
            return true;
        }
        // if a metadata file is present, check if this is the "version" directory, marking it as a project version
        ArchivaRepositoryMetadata metadata = readMetadata(dir);
        if (metadata != null && projectVersion.equals(metadata.getVersion())) {
            return true;
        }

        return false;
    }

    private ArchivaRepositoryMetadata readMetadata(StorageAsset directory) {
        ArchivaRepositoryMetadata metadata = null;
        StorageAsset metadataFile = directory.resolve(METADATA_FILENAME);
        if (metadataFile.exists()) {
            try {
                metadata = MavenMetadataReader.read(metadataFile);
            } catch (XMLException | IOException e) {
                // ignore missing or invalid metadata
            }
        }
        return metadata;
    }

    private static class DirectoryFilter
            implements Predicate<StorageAsset> {
        private final Filter<String> filter;

        public DirectoryFilter(Filter<String> filter) {
            this.filter = filter;
        }

        @Override
        public boolean test(StorageAsset dir) {
            final String name = dir.getName();
            if (!filter.accept(name)) {
                return false;
            } else if (name.startsWith(".")) {
                return false;
            } else if (!dir.isContainer()) {
                return false;
            }
            return true;
        }
    }

    private static class ArtifactDirectoryFilter
            implements Predicate<StorageAsset> {
        private final Filter<String> filter;

        private ArtifactDirectoryFilter(Filter<String> filter) {
            this.filter = filter;
        }

        @Override
        public boolean test(StorageAsset file) {
            final Set<String> checksumExts = ChecksumAlgorithm.getAllExtensions();
            final String path = file.getPath();
            final String name = file.getName();
            final String extension = StringUtils.substringAfterLast(name, ".").toLowerCase();
            // TODO compare to logic in maven-repository-layer
            if (file.isContainer()) {
                return false;
            } else if (!filter.accept(name)) {
                return false;
            } else if (name.startsWith(".") || path.contains("/.") ) {
                return false;
            } else if (checksumExts.contains(extension)) {
                return false;
            } else if (Arrays.binarySearch(IGNORED_FILES, name) >= 0) {
                return false;
            }
            // some files from remote repositories can have name like maven-metadata-archiva-vm-all-public.xml
            else if (StringUtils.startsWith(name, METADATA_FILENAME_START) && StringUtils.endsWith(name, ".xml")) {
                return false;
            }

            return true;

        }
    }


    private static final class PomFilenameFilter
            implements Predicate<StorageAsset> {

        private final String artifactId, projectVersion;

        private PomFilenameFilter(String artifactId, String projectVersion) {
            this.artifactId = artifactId;
            this.projectVersion = projectVersion;
        }

        @Override
        public boolean test(StorageAsset dir) {
            final String name = dir.getName();
            if (name.startsWith(artifactId + "-") && name.endsWith(".pom")) {
                String v = name.substring(artifactId.length() + 1, name.length() - 4);
                v = VersionUtil.getBaseVersion(v);
                if (v.equals(projectVersion)) {
                    return true;
                }
            }
            return false;
        }

    }

    private static class PomFileFilter
            implements Predicate<StorageAsset> {
        private final String pomFile;

        private PomFileFilter(String pomFile) {
            this.pomFile = pomFile;
        }

        @Override
        public boolean test(StorageAsset dir) {
            return pomFile.equals(dir.getName());
        }
    }


    public PathParser getPathParser() {
        return pathParser;
    }

    public void setPathParser(PathParser pathParser) {
        this.pathParser = pathParser;
    }
}