/*
 * 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.bridge;

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

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.maven.RepositoryUtils;
import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.DefaultArtifact;
import org.apache.maven.artifact.InvalidRepositoryException;
import org.apache.maven.artifact.handler.ArtifactHandler;
import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
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.MavenArtifactRepository;
import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout2;
import org.apache.maven.artifact.repository.layout.DefaultRepositoryLayout;
import org.apache.maven.artifact.resolver.filter.ExclusionArtifactFilter;
import org.apache.maven.artifact.versioning.InvalidVersionSpecificationException;
import org.apache.maven.artifact.versioning.VersionRange;
import org.apache.maven.execution.MavenExecutionRequest;
import org.apache.maven.model.Dependency;
import org.apache.maven.model.Plugin;
import org.apache.maven.repository.Proxy;
import org.apache.maven.settings.Mirror;
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;

/**
 * @since 3.2.3
 */
@Named("default")
@Singleton
public class MavenRepositorySystem {

    public static final String DEFAULT_REMOTE_REPO_ID = "central";

    public static final String DEFAULT_REMOTE_REPO_URL = "https://repo.maven.apache.org/maven2";

    public static final String DEFAULT_LOCAL_REPO_ID = "local";

    private final ArtifactHandlerManager artifactHandlerManager;

    private final Map<String, ArtifactRepositoryLayout> layouts;

    @Inject
    public MavenRepositorySystem(
            ArtifactHandlerManager artifactHandlerManager, Map<String, ArtifactRepositoryLayout> layouts) {
        this.artifactHandlerManager = artifactHandlerManager;
        this.layouts = layouts;
    }

    // DefaultProjectBuilder
    public Artifact createArtifact(String groupId, String artifactId, String version, String scope, String type) {
        return createArtifactX(groupId, artifactId, version, scope, type);
    }

    // DefaultProjectBuilder
    public Artifact createProjectArtifact(String groupId, String artifactId, String metaVersionId) {
        return createProjectArtifactX(groupId, artifactId, metaVersionId);
    }

    // DefaultProjectBuilder
    public Artifact createDependencyArtifact(Dependency d) {
        if (d.getVersion() == null) {
            return null;
        }

        VersionRange versionRange;
        try {
            versionRange = VersionRange.createFromVersionSpec(d.getVersion());
        } catch (InvalidVersionSpecificationException e) {
            return null;
        }

        Artifact artifact = createDependencyArtifactX(
                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()) {
            artifact.setDependencyFilter(new ExclusionArtifactFilter(d.getExclusions()));
        }

        return artifact;
    }

    // DefaultProjectBuilder
    public Artifact createExtensionArtifact(String groupId, String artifactId, String version) {
        VersionRange versionRange;
        try {
            versionRange = VersionRange.createFromVersionSpec(version);
        } catch (InvalidVersionSpecificationException e) {
            return null;
        }

        return createExtensionArtifactX(groupId, artifactId, versionRange);
    }

    // DefaultProjectBuilder
    public Artifact createParentArtifact(String groupId, String artifactId, String version) {
        return createParentArtifactX(groupId, artifactId, version);
    }

    // DefaultProjectBuilder
    public Artifact createPluginArtifact(Plugin plugin) {
        VersionRange versionRange;
        try {
            String version = plugin.getVersion();
            if (version == null || version.isEmpty()) {
                version = "RELEASE";
            }
            versionRange = VersionRange.createFromVersionSpec(version);
        } catch (InvalidVersionSpecificationException e) {
            return null;
        }

        return createPluginArtifactX(plugin.getGroupId(), plugin.getArtifactId(), versionRange);
    }

    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());
        }
    }

    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 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));
            }
        }
    }

    private ArtifactRepositoryLayout getLayout(String id) {
        return layouts.get(id);
    }

    //
    // Taken from LegacyRepositorySystem
    //

    public static org.apache.maven.model.Repository fromSettingsRepository(
            org.apache.maven.settings.Repository settingsRepository) {
        org.apache.maven.model.Repository modelRepository = new org.apache.maven.model.Repository();
        modelRepository.setId(settingsRepository.getId());
        modelRepository.setLayout(settingsRepository.getLayout());
        modelRepository.setName(settingsRepository.getName());
        modelRepository.setUrl(settingsRepository.getUrl());
        modelRepository.setReleases(fromSettingsRepositoryPolicy(settingsRepository.getReleases()));
        modelRepository.setSnapshots(fromSettingsRepositoryPolicy(settingsRepository.getSnapshots()));
        return modelRepository;
    }

    public static org.apache.maven.model.RepositoryPolicy fromSettingsRepositoryPolicy(
            org.apache.maven.settings.RepositoryPolicy settingsRepositoryPolicy) {
        org.apache.maven.model.RepositoryPolicy modelRepositoryPolicy = new org.apache.maven.model.RepositoryPolicy();
        if (settingsRepositoryPolicy != null) {
            modelRepositoryPolicy.setEnabled(settingsRepositoryPolicy.isEnabled());
            modelRepositoryPolicy.setUpdatePolicy(settingsRepositoryPolicy.getUpdatePolicy());
            modelRepositoryPolicy.setChecksumPolicy(settingsRepositoryPolicy.getChecksumPolicy());
        }
        return modelRepositoryPolicy;
    }

    public static ArtifactRepository buildArtifactRepository(org.apache.maven.settings.Repository repo)
            throws InvalidRepositoryException {
        return buildArtifactRepository(fromSettingsRepository(repo));
    }

    public static ArtifactRepository buildArtifactRepository(org.apache.maven.model.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());

            ArtifactRepositoryLayout layout = new DefaultRepositoryLayout();

            return createArtifactRepository(id, url, layout, snapshots, releases);
        } else {
            return null;
        }
    }

    public static ArtifactRepositoryPolicy buildArtifactRepositoryPolicy(
            org.apache.maven.model.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 createArtifactRepository(
            String id,
            String url,
            String layoutId,
            ArtifactRepositoryPolicy snapshots,
            ArtifactRepositoryPolicy releases)
            throws InvalidRepositoryException {
        ArtifactRepositoryLayout layout = layouts.get(layoutId);

        checkLayout(id, layoutId, layout);

        return createArtifactRepository(id, url, layout, snapshots, releases);
    }

    private void checkLayout(String repositoryId, String layoutId, ArtifactRepositoryLayout layout)
            throws InvalidRepositoryException {
        if (layout == null) {
            throw new InvalidRepositoryException(
                    String.format("Cannot find ArtifactRepositoryLayout instance for: %s %s", layoutId, repositoryId),
                    repositoryId);
        }
    }

    public static ArtifactRepository createArtifactRepository(
            String id,
            String url,
            ArtifactRepositoryLayout repositoryLayout,
            ArtifactRepositoryPolicy snapshots,
            ArtifactRepositoryPolicy releases) {
        if (snapshots == null) {
            snapshots = new ArtifactRepositoryPolicy();
        }

        if (releases == null) {
            releases = new ArtifactRepositoryPolicy();
        }

        ArtifactRepository repository;
        if (repositoryLayout instanceof ArtifactRepositoryLayout2 artifactRepositoryLayout2) {
            repository = artifactRepositoryLayout2.newMavenArtifactRepository(id, url, snapshots, releases);
        } else {
            repository = new MavenArtifactRepository(id, url, repositoryLayout, snapshots, releases);
        }

        return repository;
    }

    public static ArtifactRepository createArtifactRepository(
            String id,
            Path path,
            ArtifactRepositoryLayout repositoryLayout,
            ArtifactRepositoryPolicy snapshots,
            ArtifactRepositoryPolicy releases) {
        if (snapshots == null) {
            snapshots = new ArtifactRepositoryPolicy();
        }
        if (releases == null) {
            releases = new ArtifactRepositoryPolicy();
        }
        ArtifactRepository repository;
        if (repositoryLayout instanceof ArtifactRepositoryLayout2 artifactRepositoryLayout2) {
            repository = artifactRepositoryLayout2.newMavenArtifactRepository(
                    id, path.toUri().toString(), snapshots, releases);
        } else {
            repository = new MavenArtifactRepository(id, path, repositoryLayout, snapshots, releases);
        }

        return repository;
    }

    // ArtifactFactory
    private Artifact createArtifactX(String groupId, String artifactId, String version, String scope, String type) {
        return createArtifactX(groupId, artifactId, version, scope, type, null, null);
    }

    private Artifact createDependencyArtifactX(
            String groupId,
            String artifactId,
            VersionRange versionRange,
            String type,
            String classifier,
            String scope,
            boolean optional) {
        return createArtifactX(groupId, artifactId, versionRange, type, classifier, scope, null, optional);
    }

    private Artifact createProjectArtifactX(String groupId, String artifactId, String version) {
        return createProjectArtifactX(groupId, artifactId, version, null);
    }

    private Artifact createParentArtifactX(String groupId, String artifactId, String version) {
        return createProjectArtifactX(groupId, artifactId, version);
    }

    private Artifact createPluginArtifactX(String groupId, String artifactId, VersionRange versionRange) {
        return createArtifactX(groupId, artifactId, versionRange, "maven-plugin", null, Artifact.SCOPE_RUNTIME, null);
    }

    private Artifact createProjectArtifactX(String groupId, String artifactId, String version, String scope) {
        return createArtifactX(groupId, artifactId, version, scope, "pom");
    }

    private Artifact createExtensionArtifactX(String groupId, String artifactId, VersionRange versionRange) {
        return createArtifactX(groupId, artifactId, versionRange, "jar", null, Artifact.SCOPE_RUNTIME, null);
    }

    private Artifact createArtifactX(
            String groupId,
            String artifactId,
            String version,
            String scope,
            String type,
            String classifier,
            String inheritedScope) {
        VersionRange versionRange = null;
        if (version != null) {
            versionRange = VersionRange.createFromVersion(version);
        }
        return createArtifactX(groupId, artifactId, versionRange, type, classifier, scope, inheritedScope);
    }

    private Artifact createArtifactX(
            String groupId,
            String artifactId,
            VersionRange versionRange,
            String type,
            String classifier,
            String scope,
            String inheritedScope) {
        return createArtifactX(groupId, artifactId, versionRange, type, classifier, scope, inheritedScope, false);
    }

    @SuppressWarnings("checkstyle:parameternumber")
    private Artifact createArtifactX(
            String groupId,
            String artifactId,
            VersionRange versionRange,
            String type,
            String classifier,
            String scope,
            String inheritedScope,
            boolean optional) {
        String desiredScope = Artifact.SCOPE_RUNTIME;

        if (inheritedScope == null) {
            desiredScope = scope;
        } else if (Artifact.SCOPE_TEST.equals(scope) || Artifact.SCOPE_PROVIDED.equals(scope)) {
            return null;
        } else if (Artifact.SCOPE_COMPILE.equals(scope) && Artifact.SCOPE_COMPILE.equals(inheritedScope)) {
            // added to retain compile artifactScope. Remove if you want compile inherited as runtime
            desiredScope = Artifact.SCOPE_COMPILE;
        }

        if (Artifact.SCOPE_TEST.equals(inheritedScope)) {
            desiredScope = Artifact.SCOPE_TEST;
        }

        if (Artifact.SCOPE_PROVIDED.equals(inheritedScope)) {
            desiredScope = Artifact.SCOPE_PROVIDED;
        }

        if (Artifact.SCOPE_SYSTEM.equals(scope)) {
            // system scopes come through unchanged...
            desiredScope = Artifact.SCOPE_SYSTEM;
        }

        ArtifactHandler handler = artifactHandlerManager.getArtifactHandler(type);

        return new DefaultArtifact(
                groupId, artifactId, versionRange, desiredScope, type, classifier, handler, optional);
    }

    //
    // Code taken from LegacyRepositorySystem
    //
    public ArtifactRepository createDefaultRemoteRepository() throws Exception {
        return createDefaultRemoteRepository(null);
    }

    public ArtifactRepository createDefaultRemoteRepository(MavenExecutionRequest request) throws Exception {
        return createRepository(
                MavenRepositorySystem.DEFAULT_REMOTE_REPO_URL,
                MavenRepositorySystem.DEFAULT_REMOTE_REPO_ID,
                true,
                ArtifactRepositoryPolicy.UPDATE_POLICY_DAILY,
                false,
                ArtifactRepositoryPolicy.UPDATE_POLICY_DAILY,
                ArtifactRepositoryPolicy.DEFAULT_CHECKSUM_POLICY);
    }

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

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

        return createArtifactRepository(repositoryId, url, "default", snapshotsPolicy, releasesPolicy);
    }

    public Set<String> getRepoIds(List<ArtifactRepository> repositories) {
        Set<String> repoIds = new HashSet<>();

        if (repositories != null) {
            for (ArtifactRepository repository : repositories) {
                repoIds.add(repository.getId());
            }
        }

        return repoIds;
    }

    /**
     * Source from org.apache.maven.repository.legacy.LegacyRepositorySystem#getEffectiveRepositories
     *
     * @param repositories a list of repositories
     * @return corresponding effective repositories
     * @since 3.6.1
     */
    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 ArtifactRepository createLocalRepository(MavenExecutionRequest request, File localRepository)
            throws InvalidRepositoryException {
        return createLocalRepository(localRepository);
    }

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

    private static final String WILDCARD = "*";

    private static final String EXTERNAL_WILDCARD = "external:*";

    private static final String EXTERNAL_HTTP_WILDCARD = "external:http:*";

    public static Mirror getMirror(ArtifactRepository repository, List<Mirror> mirrors) {
        String repoId = repository.getId();

        if (repoId != null && mirrors != null) {
            for (Mirror mirror : mirrors) {
                if (repoId.equals(mirror.getMirrorOf()) && matchesLayout(repository, mirror)) {
                    return mirror;
                }
            }

            for (Mirror mirror : mirrors) {
                if (matchPattern(repository, mirror.getMirrorOf()) && matchesLayout(repository, mirror)) {
                    return mirror;
                }
            }
        }

        return null;
    }

    /**
     * This method checks if the pattern matches the originalRepository. Valid patterns:
     * <ul>
     * <li>{@code *} (since 2.0.5)= everything,</li>
     * <li>{@code external:*}  (since 2.0.9)= everything not on the localhost and not file based,</li>
     * <li>{@code external:http:*} (since 3.8.0)= any repository not on the localhost using HTTP,</li>
     * <li>{@code repo,repo1}  (since 2.0.9)= {@code repo} or {@code repo1},</li>
     * <li>{@code *,!repo1} (since 2.0.9)= everything except {@code repo1}.</li>
     * </ul>
     *
     * @param originalRepository to compare for a match.
     * @param pattern used for match.
     * @return true if the repository is a match to this pattern.
     */
    static boolean matchPattern(ArtifactRepository originalRepository, String pattern) {
        boolean result = false;
        String originalId = originalRepository.getId();

        // simple checks first to short circuit processing below.
        if (WILDCARD.equals(pattern) || pattern.equals(originalId)) {
            result = true;
        } else {
            // process the list
            String[] repos = pattern.split(",");
            for (String repo : repos) {
                // see if this is a negative match
                if (repo.length() > 1 && repo.startsWith("!")) {
                    if (repo.substring(1).equals(originalId)) {
                        // explicitly exclude. Set result and stop processing.
                        result = false;
                        break;
                    }
                }
                // check for exact match
                else if (repo.equals(originalId)) {
                    result = true;
                    break;
                }
                // check for external:*
                else if (EXTERNAL_WILDCARD.equals(repo) && isExternalRepo(originalRepository)) {
                    result = true;
                    // don't stop processing in case a future segment explicitly excludes this repo
                }
                // check for external:http:*
                else if (EXTERNAL_HTTP_WILDCARD.equals(repo) && isExternalHttpRepo(originalRepository)) {
                    result = true;
                    // don't stop processing in case a future segment explicitly excludes this repo
                } else if (WILDCARD.equals(repo)) {
                    result = true;
                    // don't stop processing in case a future segment explicitly excludes this repo
                }
            }
        }
        return result;
    }

    /**
     * Checks the URL to see if this repository refers to an external repository
     *
     * @param originalRepository
     * @return true if external.
     */
    static boolean isExternalRepo(ArtifactRepository originalRepository) {
        try {
            URL url = new URL(originalRepository.getUrl());
            return !(isLocal(url.getHost()) || url.getProtocol().equals("file"));
        } catch (MalformedURLException e) {
            // bad url just skip it here. It should have been validated already, but the wagon lookup will deal with it
            return false;
        }
    }

    private static boolean isLocal(String host) {
        return "localhost".equals(host) || "127.0.0.1".equals(host);
    }

    /**
     * Checks the URL to see if this repository refers to a non-localhost repository using HTTP.
     *
     * @param originalRepository
     * @return true if external.
     */
    static boolean isExternalHttpRepo(ArtifactRepository originalRepository) {
        try {
            URL url = new URL(originalRepository.getUrl());
            return ("http".equalsIgnoreCase(url.getProtocol())
                            || "dav".equalsIgnoreCase(url.getProtocol())
                            || "dav:http".equalsIgnoreCase(url.getProtocol())
                            || "dav+http".equalsIgnoreCase(url.getProtocol()))
                    && !isLocal(url.getHost());
        } catch (MalformedURLException e) {
            // bad url just skip it here. It should have been validated already, but the wagon lookup will deal with it
            return false;
        }
    }

    static boolean matchesLayout(ArtifactRepository repository, Mirror mirror) {
        return matchesLayout(RepositoryUtils.getLayout(repository), mirror.getMirrorOfLayouts());
    }

    /**
     * Checks whether the layouts configured for a mirror match with the layout of the repository.
     *
     * @param repoLayout The layout of the repository, may be {@code null}.
     * @param mirrorLayout The layouts supported by the mirror, may be {@code null}.
     * @return {@code true} if the layouts associated with the mirror match the layout of the original repository,
     *         {@code false} otherwise.
     */
    static boolean matchesLayout(String repoLayout, String mirrorLayout) {
        boolean result = false;

        // simple checks first to short circuit processing below.
        if ((mirrorLayout == null || mirrorLayout.isEmpty()) || WILDCARD.equals(mirrorLayout)) {
            result = true;
        } else if (mirrorLayout.equals(repoLayout)) {
            result = true;
        } else {
            // process the list
            String[] layouts = mirrorLayout.split(",");
            for (String layout : layouts) {
                // see if this is a negative match
                if (layout.length() > 1 && layout.startsWith("!")) {
                    if (layout.substring(1).equals(repoLayout)) {
                        // explicitly exclude. Set result and stop processing.
                        result = false;
                        break;
                    }
                }
                // check for exact match
                else if (layout.equals(repoLayout)) {
                    result = true;
                    break;
                } else if (WILDCARD.equals(layout)) {
                    result = true;
                    // don't stop processing in case a future segment explicitly excludes this repo
                }
            }
        }

        return result;
    }
}
