/*
 * 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.
 */
package org.apache.maven.repository.legacy;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.apache.maven.RepositoryUtils;
import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.InvalidRepositoryException;
import org.apache.maven.artifact.factory.ArtifactFactory;
import org.apache.maven.artifact.metadata.ArtifactMetadata;
import org.apache.maven.artifact.repository.ArtifactRepository;
import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
import org.apache.maven.artifact.repository.Authentication;
import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
import org.apache.maven.artifact.resolver.ArtifactResolutionRequest;
import org.apache.maven.artifact.resolver.ArtifactResolutionResult;
import org.apache.maven.artifact.resolver.ArtifactResolver;
import org.apache.maven.artifact.resolver.filter.ExcludesArtifactFilter;
import org.apache.maven.artifact.versioning.InvalidVersionSpecificationException;
import org.apache.maven.artifact.versioning.VersionRange;
import org.apache.maven.model.Dependency;
import org.apache.maven.model.Exclusion;
import org.apache.maven.model.Plugin;
import org.apache.maven.model.Repository;
import org.apache.maven.model.RepositoryPolicy;
import org.apache.maven.repository.ArtifactDoesNotExistException;
import org.apache.maven.repository.ArtifactTransferFailedException;
import org.apache.maven.repository.ArtifactTransferListener;
import org.apache.maven.repository.DelegatingLocalArtifactRepository;
import org.apache.maven.repository.LocalArtifactRepository;
import org.apache.maven.repository.MirrorSelector;
import org.apache.maven.repository.Proxy;
import org.apache.maven.repository.RepositorySystem;
import org.apache.maven.repository.legacy.repository.ArtifactRepositoryFactory;
import org.apache.maven.settings.Mirror;
import org.apache.maven.settings.Server;
import org.apache.maven.settings.building.SettingsProblem;
import org.apache.maven.settings.crypto.DefaultSettingsDecryptionRequest;
import org.apache.maven.settings.crypto.SettingsDecrypter;
import org.apache.maven.settings.crypto.SettingsDecryptionRequest;
import org.apache.maven.settings.crypto.SettingsDecryptionResult;
import org.apache.maven.wagon.proxy.ProxyInfo;
import org.apache.maven.wagon.proxy.ProxyUtils;
import org.codehaus.plexus.PlexusContainer;
import org.codehaus.plexus.component.repository.exception.ComponentLookupException;
import org.codehaus.plexus.logging.Logger;
import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.repository.AuthenticationContext;
import org.eclipse.aether.repository.AuthenticationSelector;
import org.eclipse.aether.repository.ProxySelector;
import org.eclipse.aether.repository.RemoteRepository;

/**
 */
@Named("default")
@Singleton
@Deprecated
public class LegacyRepositorySystem implements RepositorySystem {

    @Inject
    private Logger logger;

    @Inject
    private ArtifactFactory artifactFactory;

    @Inject
    private ArtifactResolver artifactResolver;

    @Inject
    private ArtifactRepositoryFactory artifactRepositoryFactory;

    @Inject
    private Map<String, ArtifactRepositoryLayout> layouts;

    @Inject
    private WagonManager wagonManager;

    @Inject
    private PlexusContainer plexus;

    @Inject
    private MirrorSelector mirrorSelector;

    @Inject
    private SettingsDecrypter settingsDecrypter;

    public Artifact createArtifact(String groupId, String artifactId, String version, String scope, String type) {
        return artifactFactory.createArtifact(groupId, artifactId, version, scope, type);
    }

    public Artifact createArtifact(String groupId, String artifactId, String version, String packaging) {
        return artifactFactory.createBuildArtifact(groupId, artifactId, version, packaging);
    }

    public Artifact createArtifactWithClassifier(
            String groupId, String artifactId, String version, String type, String classifier) {
        return artifactFactory.createArtifactWithClassifier(groupId, artifactId, version, type, classifier);
    }

    public Artifact createProjectArtifact(String groupId, String artifactId, String metaVersionId) {
        return artifactFactory.createProjectArtifact(groupId, artifactId, metaVersionId);
    }

    public Artifact createDependencyArtifact(Dependency d) {
        VersionRange versionRange;
        try {
            versionRange = VersionRange.createFromVersionSpec(d.getVersion());
        } catch (InvalidVersionSpecificationException e) {
            // MNG-5368: Log a message instead of returning 'null' silently.
            this.logger.error(
                    String.format(
                            "Invalid version specification '%s' creating dependency artifact '%s'.", d.getVersion(), d),
                    e);
            return null;
        }

        Artifact artifact = artifactFactory.createDependencyArtifact(
                d.getGroupId(),
                d.getArtifactId(),
                versionRange,
                d.getType(),
                d.getClassifier(),
                d.getScope(),
                d.isOptional());

        if (Artifact.SCOPE_SYSTEM.equals(d.getScope()) && d.getSystemPath() != null) {
            artifact.setFile(new File(d.getSystemPath()));
        }

        if (!d.getExclusions().isEmpty()) {
            List<String> exclusions = new ArrayList<>();

            for (Exclusion exclusion : d.getExclusions()) {
                exclusions.add(exclusion.getGroupId() + ':' + exclusion.getArtifactId());
            }

            artifact.setDependencyFilter(new ExcludesArtifactFilter(exclusions));
        }

        return artifact;
    }

    public Artifact createExtensionArtifact(String groupId, String artifactId, String version) {
        VersionRange versionRange;
        try {
            versionRange = VersionRange.createFromVersionSpec(version);
        } catch (InvalidVersionSpecificationException e) {
            // MNG-5368: Log a message instead of returning 'null' silently.
            this.logger.error(
                    String.format(
                            "Invalid version specification '%s' creating extension artifact '%s:%s:%s'.",
                            version, groupId, artifactId, version),
                    e);

            return null;
        }

        return artifactFactory.createExtensionArtifact(groupId, artifactId, versionRange);
    }

    public Artifact createParentArtifact(String groupId, String artifactId, String version) {
        return artifactFactory.createParentArtifact(groupId, artifactId, version);
    }

    public Artifact createPluginArtifact(Plugin plugin) {
        String version = plugin.getVersion();
        if (version == null || version.isEmpty()) {
            version = "RELEASE";
        }

        VersionRange versionRange;
        try {
            versionRange = VersionRange.createFromVersionSpec(version);
        } catch (InvalidVersionSpecificationException e) {
            // MNG-5368: Log a message instead of returning 'null' silently.
            this.logger.error(
                    String.format("Invalid version specification '%s' creating plugin artifact '%s'.", version, plugin),
                    e);

            return null;
        }

        return artifactFactory.createPluginArtifact(plugin.getGroupId(), plugin.getArtifactId(), versionRange);
    }

    public ArtifactRepositoryPolicy buildArtifactRepositoryPolicy(RepositoryPolicy policy) {
        boolean enabled = true;

        String updatePolicy = null;

        String checksumPolicy = null;

        if (policy != null) {
            enabled = policy.isEnabled();

            if (policy.getUpdatePolicy() != null) {
                updatePolicy = policy.getUpdatePolicy();
            }
            if (policy.getChecksumPolicy() != null) {
                checksumPolicy = policy.getChecksumPolicy();
            }
        }

        return new ArtifactRepositoryPolicy(enabled, updatePolicy, checksumPolicy);
    }

    public ArtifactRepository createDefaultLocalRepository() throws InvalidRepositoryException {
        return createLocalRepository(RepositorySystem.defaultUserLocalRepository);
    }

    public ArtifactRepository createLocalRepository(File localRepository) throws InvalidRepositoryException {
        return createRepository(
                "file://" + localRepository.toURI().getRawPath(),
                RepositorySystem.DEFAULT_LOCAL_REPO_ID,
                true,
                ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
                true,
                ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
                ArtifactRepositoryPolicy.CHECKSUM_POLICY_IGNORE);
    }

    public ArtifactRepository createDefaultRemoteRepository() throws InvalidRepositoryException {
        return createRepository(
                RepositorySystem.DEFAULT_REMOTE_REPO_URL,
                RepositorySystem.DEFAULT_REMOTE_REPO_ID,
                true,
                ArtifactRepositoryPolicy.UPDATE_POLICY_DAILY,
                false,
                ArtifactRepositoryPolicy.UPDATE_POLICY_DAILY,
                ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN);
    }

    public ArtifactRepository createLocalRepository(String url, String repositoryId) throws IOException {
        return createRepository(
                canonicalFileUrl(url),
                repositoryId,
                true,
                ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
                true,
                ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
                ArtifactRepositoryPolicy.CHECKSUM_POLICY_IGNORE);
    }

    private String canonicalFileUrl(String url) throws IOException {
        if (!url.startsWith("file:")) {
            url = "file://" + url;
        } else if (url.startsWith("file:") && !url.startsWith("file://")) {
            url = "file://" + url.substring("file:".length());
        }

        // So now we have an url of the form file://<path>

        // We want to eliminate any relative path nonsense and lock down the path so we
        // need to fully resolve it before any submodules use the path. This can happen
        // when you are using a custom settings.xml that contains a relative path entry
        // for the local repository setting.

        File localRepository = new File(url.substring("file://".length()));

        if (!localRepository.isAbsolute()) {
            url = "file://" + localRepository.getCanonicalPath();
        }

        return url;
    }

    public ArtifactResolutionResult resolve(ArtifactResolutionRequest request) {
        /*
         * Probably is not worth it, but here I make sure I restore request
         * to its original state.
         */
        try {
            LocalArtifactRepository ideWorkspace =
                    plexus.lookup(LocalArtifactRepository.class, LocalArtifactRepository.IDE_WORKSPACE);

            if (request.getLocalRepository() instanceof DelegatingLocalArtifactRepository) {
                DelegatingLocalArtifactRepository delegatingLocalRepository =
                        (DelegatingLocalArtifactRepository) request.getLocalRepository();

                LocalArtifactRepository orig = delegatingLocalRepository.getIdeWorkspace();

                delegatingLocalRepository.setIdeWorkspace(ideWorkspace);

                try {
                    return artifactResolver.resolve(request);
                } finally {
                    delegatingLocalRepository.setIdeWorkspace(orig);
                }
            } else {
                ArtifactRepository localRepository = request.getLocalRepository();
                DelegatingLocalArtifactRepository delegatingLocalRepository =
                        new DelegatingLocalArtifactRepository(localRepository);
                delegatingLocalRepository.setIdeWorkspace(ideWorkspace);
                request.setLocalRepository(delegatingLocalRepository);
                try {
                    return artifactResolver.resolve(request);
                } finally {
                    request.setLocalRepository(localRepository);
                }
            }
        } catch (ComponentLookupException e) {
            // no ide workspace artifact resolution
        }

        return artifactResolver.resolve(request);
    }

    //    public void addProxy( String protocol, String host, int port, String username, String password,
    //                          String nonProxyHosts )
    //    {
    //        ProxyInfo proxyInfo = new ProxyInfo();
    //        proxyInfo.setHost( host );
    //        proxyInfo.setType( protocol );
    //        proxyInfo.setPort( port );
    //        proxyInfo.setNonProxyHosts( nonProxyHosts );
    //        proxyInfo.setUserName( username );
    //        proxyInfo.setPassword( password );
    //
    //        proxies.put( protocol, proxyInfo );
    //
    //        wagonManager.addProxy( protocol, host, port, username, password, nonProxyHosts );
    //    }

    public List<ArtifactRepository> getEffectiveRepositories(List<ArtifactRepository> repositories) {
        if (repositories == null) {
            return null;
        }

        Map<String, List<ArtifactRepository>> reposByKey = new LinkedHashMap<>();

        for (ArtifactRepository repository : repositories) {
            String key = repository.getId();

            List<ArtifactRepository> aliasedRepos = reposByKey.computeIfAbsent(key, k -> new ArrayList<>());

            aliasedRepos.add(repository);
        }

        List<ArtifactRepository> effectiveRepositories = new ArrayList<>();

        for (List<ArtifactRepository> aliasedRepos : reposByKey.values()) {
            List<ArtifactRepository> mirroredRepos = new ArrayList<>();

            List<ArtifactRepositoryPolicy> releasePolicies = new ArrayList<>(aliasedRepos.size());

            for (ArtifactRepository aliasedRepo : aliasedRepos) {
                releasePolicies.add(aliasedRepo.getReleases());
                mirroredRepos.addAll(aliasedRepo.getMirroredRepositories());
            }

            ArtifactRepositoryPolicy releasePolicy = getEffectivePolicy(releasePolicies);

            List<ArtifactRepositoryPolicy> snapshotPolicies = new ArrayList<>(aliasedRepos.size());

            for (ArtifactRepository aliasedRepo : aliasedRepos) {
                snapshotPolicies.add(aliasedRepo.getSnapshots());
            }

            ArtifactRepositoryPolicy snapshotPolicy = getEffectivePolicy(snapshotPolicies);

            ArtifactRepository aliasedRepo = aliasedRepos.get(0);

            ArtifactRepository effectiveRepository = createArtifactRepository(
                    aliasedRepo.getId(), aliasedRepo.getUrl(), aliasedRepo.getLayout(), snapshotPolicy, releasePolicy);

            effectiveRepository.setAuthentication(aliasedRepo.getAuthentication());

            effectiveRepository.setProxy(aliasedRepo.getProxy());

            effectiveRepository.setMirroredRepositories(mirroredRepos);

            effectiveRepository.setBlocked(aliasedRepo.isBlocked());

            effectiveRepositories.add(effectiveRepository);
        }

        return effectiveRepositories;
    }

    private ArtifactRepositoryPolicy getEffectivePolicy(Collection<ArtifactRepositoryPolicy> policies) {
        ArtifactRepositoryPolicy effectivePolicy = null;

        for (ArtifactRepositoryPolicy policy : policies) {
            if (effectivePolicy == null) {
                effectivePolicy = new ArtifactRepositoryPolicy(policy);
            } else {
                effectivePolicy.merge(policy);
            }
        }

        return effectivePolicy;
    }

    public Mirror getMirror(ArtifactRepository repository, List<Mirror> mirrors) {
        return mirrorSelector.getMirror(repository, mirrors);
    }

    public void injectMirror(List<ArtifactRepository> repositories, List<Mirror> mirrors) {
        if (repositories != null && mirrors != null) {
            for (ArtifactRepository repository : repositories) {
                Mirror mirror = getMirror(repository, mirrors);
                injectMirror(repository, mirror);
            }
        }
    }

    private Mirror getMirror(RepositorySystemSession session, ArtifactRepository repository) {
        if (session != null) {
            org.eclipse.aether.repository.MirrorSelector selector = session.getMirrorSelector();
            if (selector != null) {
                RemoteRepository repo = selector.getMirror(RepositoryUtils.toRepo(repository));
                if (repo != null) {
                    Mirror mirror = new Mirror();
                    mirror.setId(repo.getId());
                    mirror.setUrl(repo.getUrl());
                    mirror.setLayout(repo.getContentType());
                    mirror.setBlocked(repo.isBlocked());
                    return mirror;
                }
            }
        }
        return null;
    }

    public void injectMirror(RepositorySystemSession session, List<ArtifactRepository> repositories) {
        if (repositories != null && session != null) {
            for (ArtifactRepository repository : repositories) {
                Mirror mirror = getMirror(session, repository);
                injectMirror(repository, mirror);
            }
        }
    }

    private void injectMirror(ArtifactRepository repository, Mirror mirror) {
        if (mirror != null) {
            ArtifactRepository original = createArtifactRepository(
                    repository.getId(),
                    repository.getUrl(),
                    repository.getLayout(),
                    repository.getSnapshots(),
                    repository.getReleases());

            repository.setMirroredRepositories(Collections.singletonList(original));

            repository.setId(mirror.getId());
            repository.setUrl(mirror.getUrl());

            if (mirror.getLayout() != null && !mirror.getLayout().isEmpty()) {
                repository.setLayout(getLayout(mirror.getLayout()));
            }

            repository.setBlocked(mirror.isBlocked());
        }
    }

    public void injectAuthentication(List<ArtifactRepository> repositories, List<Server> servers) {
        if (repositories != null) {
            Map<String, Server> serversById = new HashMap<>();

            if (servers != null) {
                for (Server server : servers) {
                    if (!serversById.containsKey(server.getId())) {
                        serversById.put(server.getId(), server);
                    }
                }
            }

            for (ArtifactRepository repository : repositories) {
                Server server = serversById.get(repository.getId());

                if (server != null) {
                    SettingsDecryptionRequest request = new DefaultSettingsDecryptionRequest(server);
                    SettingsDecryptionResult result = settingsDecrypter.decrypt(request);
                    server = result.getServer();

                    if (logger.isDebugEnabled()) {
                        for (SettingsProblem problem : result.getProblems()) {
                            logger.debug(problem.getMessage(), problem.getException());
                        }
                    }

                    Authentication authentication = new Authentication(server.getUsername(), server.getPassword());
                    authentication.setPrivateKey(server.getPrivateKey());
                    authentication.setPassphrase(server.getPassphrase());

                    repository.setAuthentication(authentication);
                } else {
                    repository.setAuthentication(null);
                }
            }
        }
    }

    private Authentication getAuthentication(RepositorySystemSession session, ArtifactRepository repository) {
        if (session != null) {
            AuthenticationSelector selector = session.getAuthenticationSelector();
            if (selector != null) {
                RemoteRepository repo = RepositoryUtils.toRepo(repository);
                org.eclipse.aether.repository.Authentication auth = selector.getAuthentication(repo);
                if (auth != null) {
                    repo = new RemoteRepository.Builder(repo)
                            .setAuthentication(auth)
                            .build();
                    AuthenticationContext authCtx = AuthenticationContext.forRepository(session, repo);
                    Authentication result = new Authentication(
                            authCtx.get(AuthenticationContext.USERNAME), authCtx.get(AuthenticationContext.PASSWORD));
                    result.setPrivateKey(authCtx.get(AuthenticationContext.PRIVATE_KEY_PATH));
                    result.setPassphrase(authCtx.get(AuthenticationContext.PRIVATE_KEY_PASSPHRASE));
                    authCtx.close();
                    return result;
                }
            }
        }
        return null;
    }

    public void injectAuthentication(RepositorySystemSession session, List<ArtifactRepository> repositories) {
        if (repositories != null && session != null) {
            for (ArtifactRepository repository : repositories) {
                repository.setAuthentication(getAuthentication(session, repository));
            }
        }
    }

    private org.apache.maven.settings.Proxy getProxy(
            ArtifactRepository repository, List<org.apache.maven.settings.Proxy> proxies) {
        if (proxies != null && repository.getProtocol() != null) {
            for (org.apache.maven.settings.Proxy proxy : proxies) {
                if (proxy.isActive() && repository.getProtocol().equalsIgnoreCase(proxy.getProtocol())) {
                    if (proxy.getNonProxyHosts() != null
                            && !proxy.getNonProxyHosts().isEmpty()) {
                        ProxyInfo pi = new ProxyInfo();
                        pi.setNonProxyHosts(proxy.getNonProxyHosts());

                        org.apache.maven.wagon.repository.Repository repo =
                                new org.apache.maven.wagon.repository.Repository(
                                        repository.getId(), repository.getUrl());

                        if (!ProxyUtils.validateNonProxyHosts(pi, repo.getHost())) {
                            return proxy;
                        }
                    } else {
                        return proxy;
                    }
                }
            }
        }

        return null;
    }

    public void injectProxy(List<ArtifactRepository> repositories, List<org.apache.maven.settings.Proxy> proxies) {
        if (repositories != null) {
            for (ArtifactRepository repository : repositories) {
                org.apache.maven.settings.Proxy proxy = getProxy(repository, proxies);

                if (proxy != null) {
                    SettingsDecryptionRequest request = new DefaultSettingsDecryptionRequest(proxy);
                    SettingsDecryptionResult result = settingsDecrypter.decrypt(request);
                    proxy = result.getProxy();

                    if (logger.isDebugEnabled()) {
                        for (SettingsProblem problem : result.getProblems()) {
                            logger.debug(problem.getMessage(), problem.getException());
                        }
                    }

                    Proxy p = new Proxy();
                    p.setHost(proxy.getHost());
                    p.setProtocol(proxy.getProtocol());
                    p.setPort(proxy.getPort());
                    p.setNonProxyHosts(proxy.getNonProxyHosts());
                    p.setUserName(proxy.getUsername());
                    p.setPassword(proxy.getPassword());

                    repository.setProxy(p);
                } else {
                    repository.setProxy(null);
                }
            }
        }
    }

    private Proxy getProxy(RepositorySystemSession session, ArtifactRepository repository) {
        if (session != null) {
            ProxySelector selector = session.getProxySelector();
            if (selector != null) {
                RemoteRepository repo = RepositoryUtils.toRepo(repository);
                org.eclipse.aether.repository.Proxy proxy = selector.getProxy(repo);
                if (proxy != null) {
                    Proxy p = new Proxy();
                    p.setHost(proxy.getHost());
                    p.setProtocol(proxy.getType());
                    p.setPort(proxy.getPort());
                    if (proxy.getAuthentication() != null) {
                        repo = new RemoteRepository.Builder(repo)
                                .setProxy(proxy)
                                .build();
                        AuthenticationContext authCtx = AuthenticationContext.forProxy(session, repo);
                        p.setUserName(authCtx.get(AuthenticationContext.USERNAME));
                        p.setPassword(authCtx.get(AuthenticationContext.PASSWORD));
                        p.setNtlmDomain(authCtx.get(AuthenticationContext.NTLM_DOMAIN));
                        p.setNtlmHost(authCtx.get(AuthenticationContext.NTLM_WORKSTATION));
                        authCtx.close();
                    }
                    return p;
                }
            }
        }
        return null;
    }

    public void injectProxy(RepositorySystemSession session, List<ArtifactRepository> repositories) {
        if (repositories != null && session != null) {
            for (ArtifactRepository repository : repositories) {
                repository.setProxy(getProxy(session, repository));
            }
        }
    }

    public void retrieve(
            ArtifactRepository repository,
            File destination,
            String remotePath,
            ArtifactTransferListener transferListener)
            throws ArtifactTransferFailedException, ArtifactDoesNotExistException {
        try {
            wagonManager.getRemoteFile(
                    repository,
                    destination,
                    remotePath,
                    TransferListenerAdapter.newAdapter(transferListener),
                    ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN,
                    true);
        } catch (org.apache.maven.wagon.TransferFailedException e) {
            throw new ArtifactTransferFailedException(getMessage(e, "Error transferring artifact."), e);
        } catch (org.apache.maven.wagon.ResourceDoesNotExistException e) {
            throw new ArtifactDoesNotExistException(getMessage(e, "Requested artifact does not exist."), e);
        }
    }

    public void publish(
            ArtifactRepository repository, File source, String remotePath, ArtifactTransferListener transferListener)
            throws ArtifactTransferFailedException {
        try {
            wagonManager.putRemoteFile(
                    repository, source, remotePath, TransferListenerAdapter.newAdapter(transferListener));
        } catch (org.apache.maven.wagon.TransferFailedException e) {
            throw new ArtifactTransferFailedException(getMessage(e, "Error transferring artifact."), e);
        }
    }

    //
    // Artifact Repository Creation
    //
    public ArtifactRepository buildArtifactRepository(Repository repo) throws InvalidRepositoryException {
        if (repo != null) {
            String id = repo.getId();

            if (id == null || id.isEmpty()) {
                throw new InvalidRepositoryException("Repository identifier missing", "");
            }

            String url = repo.getUrl();

            if (url == null || url.isEmpty()) {
                throw new InvalidRepositoryException("URL missing for repository " + id, id);
            }

            ArtifactRepositoryPolicy snapshots = buildArtifactRepositoryPolicy(repo.getSnapshots());

            ArtifactRepositoryPolicy releases = buildArtifactRepositoryPolicy(repo.getReleases());

            return createArtifactRepository(id, url, getLayout(repo.getLayout()), snapshots, releases);
        } else {
            return null;
        }
    }

    private ArtifactRepository createRepository(
            String url,
            String repositoryId,
            boolean releases,
            String releaseUpdates,
            boolean snapshots,
            String snapshotUpdates,
            String checksumPolicy) {
        ArtifactRepositoryPolicy snapshotsPolicy =
                new ArtifactRepositoryPolicy(snapshots, snapshotUpdates, checksumPolicy);

        ArtifactRepositoryPolicy releasesPolicy =
                new ArtifactRepositoryPolicy(releases, releaseUpdates, checksumPolicy);

        return createArtifactRepository(repositoryId, url, null, snapshotsPolicy, releasesPolicy);
    }

    public ArtifactRepository createArtifactRepository(
            String repositoryId,
            String url,
            ArtifactRepositoryLayout repositoryLayout,
            ArtifactRepositoryPolicy snapshots,
            ArtifactRepositoryPolicy releases) {
        if (repositoryLayout == null) {
            repositoryLayout = layouts.get("default");
        }
        return artifactRepositoryFactory.createArtifactRepository(
                repositoryId, url, repositoryLayout, snapshots, releases);
    }

    private static String getMessage(Throwable error, String def) {
        if (error == null) {
            return def;
        }
        String msg = error.getMessage();
        if (msg != null && !msg.isEmpty()) {
            return msg;
        }
        return getMessage(error.getCause(), def);
    }

    private ArtifactRepositoryLayout getLayout(String id) {
        ArtifactRepositoryLayout layout = layouts.get(id);

        if (layout == null) {
            layout = new UnknownRepositoryLayout(id, layouts.get("default"));
        }

        return layout;
    }

    /**
     * In the future, the legacy system might encounter repository types for which no layout components exists because
     * the actual communication with the repository happens via a repository connector. As a minimum, the legacy system
     * needs to retain the id of this layout so that the content type of the remote repository can still be accurately
     * described.
     */
    static class UnknownRepositoryLayout implements ArtifactRepositoryLayout {

        private final String id;

        private final ArtifactRepositoryLayout fallback;

        UnknownRepositoryLayout(String id, ArtifactRepositoryLayout fallback) {
            this.id = id;
            this.fallback = fallback;
        }

        public String getId() {
            return id;
        }

        public String pathOf(Artifact artifact) {
            return fallback.pathOf(artifact);
        }

        public String pathOfLocalRepositoryMetadata(ArtifactMetadata metadata, ArtifactRepository repository) {
            return fallback.pathOfLocalRepositoryMetadata(metadata, repository);
        }

        public String pathOfRemoteRepositoryMetadata(ArtifactMetadata metadata) {
            return fallback.pathOfRemoteRepositoryMetadata(metadata);
        }

        @Override
        public String toString() {
            return getId();
        }
    }
}