/*
 * CDDL HEADER START
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 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
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 *
 * See LICENSE.txt included in this distribution for the specific
 * language governing permissions and limitations under the License.
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 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at LICENSE.txt.
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/* Portions Copyright 2008 Peter Bray */
package org.opensolaris.opengrok.history;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.zip.GZIPInputStream;

/**
 * <p>
 * Razor Repository implementation.
 *</p><p>
 * A brief and simplistic overview of Razor
 *</p><p>
 * Razor uses the term 'Group' for what might traditionally be called a
 * repository, that is a collection of files and folders. A collection of
 * Groups is called a 'Universe' in Razor. Razor supports multiple Universes,
 * and these are the units which can be independently started and stopped.
 *</p><p>
 * A universe usually consists of on issue tracking data set called "Issues",
 * this is managed from a user perspective by a GUI called 'issues' or a web
 * interface called 'issue weaver'. Each group has a file repository, managed
 * by a GUI called 'versions', and an associated GUI called 'threads' is used
 * to collect together related versions of files into a "Thread", which can
 * be thought of as a like a tag against the repository, but is managed outside
 * of the file repository itself.
 *</p><p>
 * From the point of view of the user, they raise an issue to document a unit
 * of work, make changes to a collection of files against that issue, and then
 * combine one or more issues into a thread to represent a releasable product.
 * Of course, there is more to the product then this brief outline can do
 * justice to but these general concepts should assist in understanding the
 * concepts presented in the OpenGrok Razor Repository interface.
 *</p><p>
 * At an implementation level, a Universe consists of it Issues database,
 * and one or more Groups each consisting of file repository and thread
 * repository. Each of these repositories is implemented with a series of
 * directories (Archive, History, Info, Scripts and Tables). When file revision
 * control is needed on a file (both committed files and some internal
 * implementation files), Razor supports the use of either SCCS or RCS
 * for non-binary files and numbered compressed instances of binary files.
 * Each file is given a unique (per universe) numerical identifier in the
 * file .../razor_db/<universe>/RAZOR_UNIVERSE/Mapping, this is used by Razor
 * to track files over time, as they renamed or deleted.
 *</p><p>
 * Unfortunately, the Razor command line interface does not support features
 * that other SCMS support like 'log' and 'annotate'. Also, Razor check-outs
 * leave no indication that the files are from a centralised repository, so
 * it will not be possible to implement this module from a copy or check-out
 * of the repository, we will have to access (in a read-only manner) the actual
 * repository itself, extracting the information directly or via SCCS/RCS
 * interfaces.
 *</p><p>
 * IMPLEMENTATION NOTES:
 *</p><p>
 * The Razor implementation used for development and testing of this code
 * has the following properties which may affect the success of others
 * trying to use this implementation:
 *</p><p>
 *   - Multiple Universes<br/>
 *   - Each Universe had Issues databases<br/>
 *   - Each Universe has multiple Groups, with Threads but no Projects<br/>
 *   - The file repository format chosen was the non-default implementation,<br/>
 *     that is, RCS rather than the default SCCS implementation<br/>
 *   - Binary files are compressed with the standard UNIX 'compress' tool<br/>
 *   - Not all Groups would be suitable for OpenGrok analysis<br/>
 *   - Use of Razor command line interface was deemed impractical<br/>
 *   - The use of the Mapping file and the tracking of renamed and deleted 
 *     files was deemed too complex for the first implementation attempt<br/>
 *   - The Razor implementation was on a single Sun Solaris SPARC Server<br/>
 *   - The code development/testing used NetBeans-6.1 and Sun JDK 6 Update 6
 *</p><p>
 * The initial implementation was to create symbolic links in the SRC_ROOT
 * directory to the Razor Group directories you wished OpenGrok to process.
 * The Razor implementation of HistoryParser and DirectoryHistoryParser were
 * functional, but the file analysis infrastructure could not support the
 * virtual filesystem that I was creating in my implementation of the
 * DirectoryHistoryParser for Razor. Essentially I was trying to make a
 * virtual file system, and remap all file names as required, but the file
 * analysis code assumed it could just read actual directories and process
 * their contents. I would have had to implement a VirtualFile and possibly
 * VirtualFilesystem classes, recode the file analysis framework and develop
 * Standard and Razor implementations. THIS APPROACH HAS BEEN ABORTED!!!
 *</p><p>
 * The implementation now requires that you checkout a read-only copy of
 * the directories you wish OpenGrok to process, and place in the top-level
 * directory of each, a symlink called ".razor" to the Razor Group directory
 * for that folder. Example: if you have a universe called MyUniverse,
 * containing a group called MyGroup with top-level folders called Documentation
 * and Implementation. Then in SRC_ROOT (or a sub-directory of it), check-out
 * read-only say the Implementation into $SRC_ROOT, and create a symlink called
 * $SRC_ROOT/Implementation/.razor which points to a directory of the form
 * <prefix>/razor_db/<Universe>/RAZOR_UNIVERSE/DOMAIN_01/<GroupName>, so that
 * might be /repository/razor/razor_db/MyUniverse/RAZOR_UNIVERSE/DOMAIN_01/MyGroup
 *</p><p>
 * Because of the distributed nature of information storage in Razor (by this
 * I mean, that each file in the repository is represented by files of the
 * same name (and path) under multiple directories (Archive, History & Info)),
 * I'm continuously mapping SRC_ROOT based names into the appropriate
 * subdirectory of the actual repository.
 *</p><p>
 * The current implementation assumes the use of a UNIX platform, but I will
 * try not to hard-code too much in relation to these assumptions. Also I have
 * not worked Java for almost 8 years now, so please forgive any oversights
 * in this regard.
 *</p>
 * @see <a href="http://www.visible.com/Products/Razor/index.htm">Razor Home</a>
 * 
 * @author Peter Bray <Peter.Darren.Bray@gmail.com>
 */
public class RazorRepository extends Repository {
    private static final Logger logger = 
        Logger.getLogger(RazorRepository.class.getName());
    private static final long serialVersionUID = 1L;

    // The path of the repository itself is stored in the super class.
    // The directory containing our repository directory (usually SRC_ROOT,
    // but if the user is nesting Razor repositories in structured tree...)
    private String sourceRootDir;
    // The base directory of that Razor Group (.razor symlink destination)
    private String groupBaseDir;

    /**
     * Create a new instance of type {@code Razor}.
     */
    public RazorRepository() {
        type = "Razor";
        working = Boolean.TRUE;
        datePattern = "yyyy/MM/dd,hh:mm:ss";
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void setDirectoryName(String directoryName) {
        super.setDirectoryName(directoryName);
        File baseDir = new File(directoryName);
        sourceRootDir = baseDir.getParentFile().getAbsolutePath();
        groupBaseDir = new File(directoryName, ".razor").getAbsolutePath();
    }

    /**
     * Get the directory, which contains this repository.
     * @return per default the parent of {@link #getDirectoryName()}
     */
    public String getSourceRootDir() {
        return sourceRootDir;
    }

    /**
     * Set the directory, which contains this repository.
     * @param path  usually the parent of {@link #getDirectoryName()}
     */
    public void setSourceRootDir(String path) {
        sourceRootDir = path;
    }

    /**
     * Get this repo's meta data directory.
     * @return per default {@link #getDirectoryName()}/.razor
     */
    public String getGroupBaseDir() {
        return groupBaseDir;
    }

    /**
     * Set this repo's meta data directory.
     * @param path  usually {@link #getDirectoryName()}/.razor
     */
    public void setGroupBaseDir(String path) {
        groupBaseDir = path;
    }

    File getRazorHistoryFileFor(File file) throws IOException {
        return pathTranslation(file, "/History/", "", "");
    }

    private File getRazorArchiveRCSFileFor(File file) throws IOException {
        return pathTranslation(file, "/Archive/RZ_VCS/", "", ",v");
    }

    private File getRazorArchiveBinaryFileFor(File file, String rev) 
        throws IOException
    {
        return pathTranslation(file, "/Archive/BINARY/", "", "@" + rev + ".Z");
    }

    private File getRazorArchiveSCCSFileFor(File file) throws IOException {
        return pathTranslation(file, "/Archive/SCCS/", "s.", "");
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean fileHasHistory( File file) {
        // @TODO : Rename & Delete Support
        try {
            File mappedFile = getRazorHistoryFileFor(file);
            return mappedFile.exists() && mappedFile.isFile();
        } catch (Exception e) {
            return false;
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public InputStream getHistoryGet( String parent, String basename, String rev) {
        // @TODO : Rename & Delete Support
        try {
            File binaryFile =
                getRazorArchiveBinaryFileFor(new File(parent, basename), rev);
            if (binaryFile != null && binaryFile.exists()) {
                // @TODO : Implement a UNIX Compress decompression input stream
                // The standard Razor implementation uses UNIX Compress, so we
                // need to be able to decompress these files. This GZIP based
                // implementation will be useful to sites using GZIP as a
                // UNIX Compress replacement (A supported configuration
                // according to to the Razor 4.x/5.x manuals)
                return new GZIPInputStream(new FileInputStream(binaryFile));
            }

            File rcsFile = getRazorArchiveRCSFileFor(new File(parent, basename));
            if (rcsFile != null && rcsFile.exists()) {
                String rcsPath = rcsFile.getPath();
                return new BufferedInputStream(new RCSget(rcsPath, rev));
            }

            File sccsFile = getRazorArchiveSCCSFileFor(new File(parent, basename));
            if (sccsFile != null && sccsFile.exists()) {
                ensureCommand(SCCSRepository.CMD_PROPERTY_KEY,
                    SCCSRepository.CMD_FALLBACK);
                return SCCSget.getRevision(cmd, sccsFile, rev);
            }
        } catch (Exception e) {
            logger.warning("Failed to get history for '" + parent + File.separator
                +  basename + "' rev='" + rev + "': " + e.getMessage());
            logger.log(Level.FINE, "getHistoryGet", e);
        }
        return null;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected Annotation annotate( File file, String revision) throws IOException {
        // @TODO : Rename & Delete Support
        File rcsFile = getRazorArchiveRCSFileFor(file);
        if (rcsFile != null && rcsFile.exists()) {
            return RCSRepository.annotate(file, revision, rcsFile);
        }

        File sccsFile = getRazorArchiveSCCSFileFor(file);
        if (sccsFile != null && sccsFile.exists()) {
            // @TODO : Don't create new SCCSRepositories unnecessarily
            return (new SCCSRepository()).annotate(sccsFile, revision);
        }

        return null;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean fileHasAnnotation( File file) {
        // @TODO : Rename & Delete Support
        try {
            File mappedFile = getRazorArchiveRCSFileFor(file);
            if (mappedFile.exists() && mappedFile.isFile()) {
                return true;
            }

            mappedFile = getRazorArchiveSCCSFileFor(file);
            if (mappedFile.exists() && mappedFile.isFile()) {
                return true;
            }
            return false;
        } catch (Exception e) {
            return false;
        }
    }

    @Override
    void update() {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    private File pathTranslation(File file, String intermediateElements,
        String filePrefix, String fileSuffix) throws IOException
    {
        File f = file;

        if (!f.getAbsolutePath().startsWith(sourceRootDir)) {
            throw new IOException("Invalid Path for Translation '" + f.getPath()
                + "', '" + intermediateElements + "', '" + filePrefix + "', '"
                + fileSuffix + "'");
        }

        if (filePrefix.length() != 0) {
            f = new File(f.getParent(), filePrefix + f.getName());
        }

        StringBuffer path = new StringBuffer(groupBaseDir);
        path.append(intermediateElements);

        if (f.getAbsolutePath().length() > sourceRootDir.length()) {
            path.append(f.getAbsolutePath()
                .substring(sourceRootDir.length() + 1));
        }

        if (fileSuffix.length() != 0) {
            path.append(fileSuffix);
        }

        return new File(path.toString());
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean isRepositoryFor( File file) {
        File f = new File(file, ".razor");
        return f.exists() && f.isDirectory();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean hasHistoryForDirectories() {
        return false;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public History getHistory(File file) throws HistoryException {
        return new RazorHistoryParser().parse(file, this);
    }
}