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 java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.archiva.checksum.ChecksumAlgorithm;
import org.apache.archiva.checksum.ChecksummedFile;
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.ProjectVersionReference;
import org.apache.archiva.metadata.repository.MetadataRepository;
import org.apache.archiva.metadata.repository.MetadataResolutionException;
import org.apache.archiva.metadata.repository.filter.AllFilter;
import org.apache.archiva.metadata.repository.filter.Filter;
import org.apache.archiva.metadata.repository.storage.RepositoryPathTranslator;
import org.apache.archiva.metadata.repository.storage.StorageMetadataResolver;
import org.apache.archiva.reports.RepositoryProblemFacet;
import org.apache.maven.archiva.common.utils.VersionUtil;
import org.apache.maven.archiva.configuration.ArchivaConfiguration;
import org.apache.maven.archiva.configuration.ManagedRepositoryConfiguration;
import org.apache.maven.archiva.xml.XMLException;
import org.apache.maven.model.CiManagement;
import org.apache.maven.model.Dependency;
import org.apache.maven.model.IssueManagement;
import org.apache.maven.model.License;
import org.apache.maven.model.MailingList;
import org.apache.maven.model.Model;
import org.apache.maven.model.Organization;
import org.apache.maven.model.Scm;
import org.apache.maven.model.building.DefaultModelBuildingRequest;
import org.apache.maven.model.building.ModelBuilder;
import org.apache.maven.model.building.ModelBuildingException;
import org.apache.maven.model.building.ModelBuildingRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @plexus.component role="org.apache.archiva.metadata.repository.storage.StorageMetadataResolver" role-hint="maven2"
 */
public class Maven2RepositoryMetadataResolver
    implements StorageMetadataResolver
{
    /**
     * @plexus.requirement
     */
    private ModelBuilder builder;

    /**
     * @plexus.requirement
     */
    private ArchivaConfiguration archivaConfiguration;

    /**
     * @plexus.requirement role-hint="maven2"
     */
    private RepositoryPathTranslator pathTranslator;

    /**
     * @plexus.requirement
     */
    private MetadataRepository metadataRepository;

    private final static Logger log = LoggerFactory.getLogger( Maven2RepositoryMetadataResolver.class );

    private static final String METADATA_FILENAME = "maven-metadata.xml";

    private static final Filter<String> ALL = new AllFilter<String>();

    private static final String PROBLEM_MISSING_POM = "missing-pom";

    private static final String PROBLEM_INVALID_POM = "invalid-pom";

    private static final String PROBLEM_MISLOCATED_POM = "mislocated-pom";

    private static final List<String> POTENTIAL_PROBLEMS =
        Arrays.asList( PROBLEM_INVALID_POM, PROBLEM_MISSING_POM, PROBLEM_MISLOCATED_POM );

    public ProjectMetadata getProject( 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;
    }

    public ProjectVersionMetadata getProjectVersion( String repoId, String namespace, String projectId,
                                                     String projectVersion )
        throws MetadataResolutionException
    {
        // TODO: an event mechanism would remove coupling to the problem reporting plugin
        // TODO: this removes all problems - do we need something that just removes the problems created by this resolver?
        String name = RepositoryProblemFacet.createName( namespace, projectId, projectVersion, null );
        metadataRepository.removeMetadataFacet( repoId, RepositoryProblemFacet.FACET_ID, name );

        ManagedRepositoryConfiguration repositoryConfiguration =
            archivaConfiguration.getConfiguration().findManagedRepositoryById( repoId );

        String artifactVersion = projectVersion;

        File basedir = new File( repositoryConfiguration.getLocation() );
        if ( VersionUtil.isSnapshot( projectVersion ) )
        {
            File metadataFile =
                pathTranslator.toFile( basedir, namespace, projectId, projectVersion, METADATA_FILENAME );
            try
            {
                MavenRepositoryMetadata metadata = MavenRepositoryMetadataReader.read( metadataFile );

                // re-adjust to timestamp if present, otherwise retain the original -SNAPSHOT filename
                MavenRepositoryMetadata.Snapshot 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 e )
            {
                // unable to parse metadata - log it, and continue with the version as the original SNAPSHOT version
                log.warn( "Invalid metadata: " + metadataFile + " - " + e.getMessage() );
            }
        }

        String id = projectId + "-" + artifactVersion + ".pom";
        File file = pathTranslator.toFile( basedir, namespace, projectId, projectVersion, id );

        if ( !file.exists() )
        {
            // TODO: an event mechanism would remove coupling to the problem reporting plugin
            addProblemReport( repoId, namespace, projectId, projectVersion, PROBLEM_MISSING_POM,
                              "The artifact's POM file '" + file + "' was missing" );

            // metadata could not be resolved
            return null;
        }

        ModelBuildingRequest req = new DefaultModelBuildingRequest();
        req.setProcessPlugins( false );
        req.setPomFile( file );
        req.setModelResolver( new RepositoryModelResolver( basedir, pathTranslator ) );
        req.setValidationLevel( ModelBuildingRequest.VALIDATION_LEVEL_MINIMAL );

        Model model;
        try
        {
            model = builder.build( req ).getEffectiveModel();
        }
        catch ( ModelBuildingException e )
        {
            addProblemReport( repoId, namespace, projectId, projectVersion, PROBLEM_INVALID_POM,
                              "The artifact's POM file '" + file + "' was invalid: " + e.getMessage() );

            throw new MetadataResolutionException( e.getMessage() );
        }

        // Check if the POM is in the correct location
        boolean correctGroupId = namespace.equals( model.getGroupId() );
        boolean correctArtifactId = projectId.equals( model.getArtifactId() );
        boolean correctVersion = projectVersion.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() );
            }

            String msg = message.toString();
            addProblemReport( repoId, namespace, projectId, projectVersion, PROBLEM_MISLOCATED_POM, msg );

            throw new MetadataResolutionException( msg );
        }

        ProjectVersionMetadata metadata = new ProjectVersionMetadata();
        metadata.setCiManagement( convertCiManagement( model.getCiManagement() ) );
        metadata.setDescription( model.getDescription() );
        metadata.setId( projectVersion );
        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() );

        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;
    }

    private void addProblemReport( String repoId, String namespace, String projectId, String projectVersion,
                                   String problemId, String message )
    {
        // TODO: an event mechanism would remove coupling to the problem reporting plugin
        RepositoryProblemFacet problem = new RepositoryProblemFacet();
        problem.setProblem( problemId );
        problem.setMessage( message );
        problem.setProject( projectId );
        problem.setNamespace( namespace );
        problem.setRepositoryId( repoId );
        problem.setVersion( projectVersion );

        metadataRepository.addMetadataFacet( repoId, problem );
    }

    private List<org.apache.archiva.metadata.model.Dependency> convertDependencies( List<Dependency> dependencies )
    {
        List<org.apache.archiva.metadata.model.Dependency> l =
            new ArrayList<org.apache.archiva.metadata.model.Dependency>();
        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.setGroupId( 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<org.apache.archiva.metadata.model.License>();
        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<org.apache.archiva.metadata.model.MailingList>();
        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;
    }

    public Collection<String> getArtifactVersions( String repoId, String namespace, String projectId,
                                                   String projectVersion )
    {
        // TODO: useful, but not implemented yet, not called from DefaultMetadataResolver
        throw new UnsupportedOperationException();
    }

    public Collection<ProjectVersionReference> getProjectReferences( String repoId, String namespace, String projectId,
                                                                     String projectVersion )
    {
        // Can't be determined on a Maven 2 repository
        throw new UnsupportedOperationException();
    }

    public Collection<String> getRootNamespaces( String repoId )
    {
        return getRootNamespaces( repoId, ALL );
    }

    public Collection<String> getRootNamespaces( String repoId, Filter<String> filter )
    {
        File dir = getRepositoryBasedir( repoId );

        String[] files = dir.list( new DirectoryFilter( filter ) );
        return files != null ? Arrays.asList( files ) : Collections.<String>emptyList();
    }

    private File getRepositoryBasedir( String repoId )
    {
        ManagedRepositoryConfiguration repositoryConfiguration =
            archivaConfiguration.getConfiguration().findManagedRepositoryById( repoId );

        return new File( repositoryConfiguration.getLocation() );
    }

    public Collection<String> getNamespaces( String repoId, String namespace )
    {
        return getNamespaces( repoId, namespace, ALL );
    }

    public Collection<String> getNamespaces( String repoId, String namespace, Filter<String> filter )
    {
        File dir = pathTranslator.toFile( getRepositoryBasedir( repoId ), namespace );

        // scan all the directories which are potential namespaces. Any directories known to be projects are excluded
        Collection<String> namespaces = new ArrayList<String>();
        File[] files = dir.listFiles( new DirectoryFilter( filter ) );
        if ( files != null )
        {
            for ( File file : files )
            {
                if ( !isProject( file, filter ) )
                {
                    namespaces.add( file.getName() );
                }
            }
        }
        return namespaces;
    }

    public Collection<String> getProjects( String repoId, String namespace )
    {
        return getProjects( repoId, namespace, ALL );
    }

    public Collection<String> getProjects( String repoId, String namespace, Filter<String> filter )
    {
        File dir = pathTranslator.toFile( getRepositoryBasedir( repoId ), namespace );

        // scan all directories in the namespace, and only include those that are known to be projects
        Collection<String> projects = new ArrayList<String>();
        File[] files = dir.listFiles( new DirectoryFilter( filter ) );
        if ( files != null )
        {
            for ( File file : files )
            {
                if ( isProject( file, filter ) )
                {
                    projects.add( file.getName() );
                }
            }
        }
        return projects;
    }

    public Collection<String> getProjectVersions( String repoId, String namespace, String projectId )
    {
        return getProjectVersions( repoId, namespace, projectId, ALL );
    }

    public Collection<ArtifactMetadata> getArtifacts( String repoId, String namespace, String projectId,
                                                      String projectVersion )
    {
        return getArtifacts( repoId, namespace, projectId, projectVersion, ALL );
    }

    public Collection<String> getProjectVersions( String repoId, String namespace, String projectId,
                                                  Filter<String> filter )
    {
        File dir = pathTranslator.toFile( getRepositoryBasedir( repoId ), namespace, projectId );

        // all directories in a project directory can be considered a version
        String[] files = dir.list( new DirectoryFilter( filter ) );
        return files != null ? Arrays.asList( files ) : Collections.<String>emptyList();
    }

    public Collection<ArtifactMetadata> getArtifacts( String repoId, String namespace, String projectId,
                                                      String projectVersion, Filter<String> filter )
    {
        File dir = pathTranslator.toFile( getRepositoryBasedir( repoId ), namespace, projectId, projectVersion );

        // all files that are not metadata and not a checksum / signature are considered artifacts
        File[] files = dir.listFiles( new ArtifactDirectoryFilter( filter ) );

        List<ArtifactMetadata> artifacts = new ArrayList<ArtifactMetadata>();
        if ( files != null )
        {
            for ( File file : files )
            {
                ArtifactMetadata metadata = new ArtifactMetadata();
                metadata.setId( file.getName() );
                metadata.setProject( projectId );
                metadata.setNamespace( namespace );
                metadata.setRepositoryId( repoId );
                metadata.setWhenGathered( new Date() );
                metadata.setFileLastModified( file.lastModified() );
                ChecksummedFile checksummedFile = new ChecksummedFile( file );
                try
                {
                    metadata.setMd5( checksummedFile.calculateChecksum( ChecksumAlgorithm.MD5 ) );
                }
                catch ( IOException e )
                {
                    log.error( "Unable to checksum file " + file + ": " + e.getMessage() );
                }
                try
                {
                    metadata.setSha1( checksummedFile.calculateChecksum( ChecksumAlgorithm.SHA1 ) );
                }
                catch ( IOException e )
                {
                    log.error( "Unable to checksum file " + file + ": " + e.getMessage() );
                }
                metadata.setSize( file.length() );

                // TODO: very crude, migrate the functionality from the repository-layer here
                if ( VersionUtil.isGenericSnapshot( projectVersion ) )
                {
                    String mainVersion =
                        projectVersion.substring( 0, projectVersion.length() - 8 ); // 8 is length of "SNAPSHOT"
                    Matcher m = Pattern.compile( projectId + "-" + mainVersion + "([0-9]{8}.[0-9]{6}-[0-9]+).*" ).matcher(
                        file.getName() );
                    m.matches();
                    String version = mainVersion + m.group( 1 );

                    metadata.setVersion( version );
                }
                else
                {
                    metadata.setVersion( projectVersion );
                }
                artifacts.add( metadata );
            }
        }
        return artifacts;
    }

    private boolean isProject( File dir, Filter<String> filter )
    {
        // scan directories for a valid project version subdirectory, meaning this must be a project directory
        File[] files = dir.listFiles( new DirectoryFilter( filter ) );
        if ( files != null )
        {
            for ( File file : files )
            {
                if ( isProjectVersion( file ) )
                {
                    return true;
                }
            }
        }

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

        return false;
    }

    private boolean isProjectVersion( File dir )
    {
        final String artifactId = dir.getParentFile().getName();
        final String projectVersion = dir.getName();

        // check if there is a POM artifact file to ensure it is a version directory
        File[] files;
        if ( VersionUtil.isSnapshot( projectVersion ) )
        {
            files = dir.listFiles( new FilenameFilter()
            {
                public boolean accept( File dir, String name )
                {
                    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;
                }
            } );
        }
        else
        {
            final String pomFile = artifactId + "-" + projectVersion + ".pom";
            files = dir.listFiles( new FilenameFilter()
            {
                public boolean accept( File dir, String name )
                {
                    return pomFile.equals( name );
                }
            } );
        }
        if ( files != null && files.length > 0 )
        {
            return true;
        }

        // if a metadata file is present, check if this is the "version" directory, marking it as a project version
        MavenRepositoryMetadata metadata = readMetadata( dir );
        if ( metadata != null && projectVersion.equals( metadata.getVersion() ) )
        {
            return true;
        }

        return false;
    }

    private MavenRepositoryMetadata readMetadata( File directory )
    {
        MavenRepositoryMetadata metadata = null;
        File metadataFile = new File( directory, METADATA_FILENAME );
        if ( metadataFile.exists() )
        {
            try
            {
                metadata = MavenRepositoryMetadataReader.read( metadataFile );
            }
            catch ( XMLException e )
            {
                // ignore missing or invalid metadata
            }
        }
        return metadata;
    }

    public void setConfiguration( ArchivaConfiguration configuration )
    {
        this.archivaConfiguration = configuration;
    }

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

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

        public boolean accept( File dir, String name )
        {
            if ( !filter.accept( name ) )
            {
                return false;
            }
            else if ( name.startsWith( "." ) )
            {
                return false;
            }
            else if ( !new File( dir, name ).isDirectory() )
            {
                return false;
            }
            return true;
        }
    }

    private class ArtifactDirectoryFilter
        implements FilenameFilter
    {
        private final Filter<String> filter;

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

        public boolean accept( File dir, String name )
        {
            // TODO compare to logic in maven-repository-layer
            if ( !filter.accept( name ) )
            {
                return false;
            }
            else if ( name.startsWith( "." ) )
            {
                return false;
            }
            else if ( name.endsWith( ".md5" ) || name.endsWith( ".sha1" ) || name.endsWith( ".asc" ) )
            {
                return false;
            }
            else if ( name.equals( METADATA_FILENAME ) )
            {
                return false;
            }
            else if ( new File( dir, name ).isDirectory() )
            {
                return false;
            }
            return true;
        }
    }
}