/*
    * Copyright (C) 2012, Matthias Sohn <matthias.sohn@sap.com> and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
    */
  package org.eclipse.jgit.api;
  
  import java.io.IOException;
  import java.text.MessageFormat;
  import java.text.ParseException;
  import java.util.Date;
  import java.util.Properties;
  import java.util.concurrent.ExecutionException;
  
  import org.eclipse.jgit.api.errors.GitAPIException;
  import org.eclipse.jgit.api.errors.JGitInternalException;
  import org.eclipse.jgit.internal.JGitText;
  import org.eclipse.jgit.internal.storage.dfs.DfsGarbageCollector;
  import org.eclipse.jgit.internal.storage.dfs.DfsRepository;
  import org.eclipse.jgit.internal.storage.file.FileRepository;
  import org.eclipse.jgit.internal.storage.file.GC;
  import org.eclipse.jgit.internal.storage.file.GC.RepoStatistics;
  import org.eclipse.jgit.lib.ConfigConstants;
  import org.eclipse.jgit.lib.ProgressMonitor;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.lib.StoredConfig;
  import org.eclipse.jgit.storage.pack.PackConfig;
  
  /**
   * A class used to execute a {@code gc} command. It has setters for all
   * supported options and arguments of this command and a {@link #call()} method
   * to finally execute the command. Each instance of this class should only be
   * used for one invocation of the command (means: one call to {@link #call()})
   *
   * @since 2.2
   * @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-gc.html"
   *      >Git documentation about gc</a>
   */
  public class GarbageCollectCommand extends GitCommand<Properties> {
  	/**
  	 * Default value of maximum delta chain depth during aggressive garbage
  	 * collection: {@value}
  	 *
  	 * @since 3.6
  	 */
  	public static final int DEFAULT_GC_AGGRESSIVE_DEPTH = 250;
  
  	/**
  	 * Default window size during packing during aggressive garbage collection:
  	 * * {@value}
  	 *
  	 * @since 3.6
  	 */
  	public static final int DEFAULT_GC_AGGRESSIVE_WINDOW = 250;
  
  	private ProgressMonitor monitor;
  
  	private Date expire;
  
  	private PackConfig pconfig;
  
  	/**
  	 * Constructor for GarbageCollectCommand.
  	 *
  	 * @param repo
  	 *            a {@link org.eclipse.jgit.lib.Repository} object.
  	 */
  	protected GarbageCollectCommand(Repository repo) {
  		super(repo);
  		pconfig = new PackConfig(repo);
  	}
  
  	/**
  	 * Set progress monitor
  	 *
  	 * @param monitor
  	 *            a progress monitor
  	 * @return this instance
  	 */
  	public GarbageCollectCommand setProgressMonitor(ProgressMonitor monitor) {
  		this.monitor = monitor;
  		return this;
  	}
  
  	/**
  	 * During gc() or prune() each unreferenced, loose object which has been
  	 * created or modified after <code>expire</code> will not be pruned. Only
  	 * older objects may be pruned. If set to null then every object is a
  	 * candidate for pruning. Use {@link org.eclipse.jgit.util.GitDateParser} to
  	 * parse time formats used by git gc.
  	 *
  	 * @param expire
  	 *            minimal age of objects to be pruned.
  	 * @return this instance
  	 */
 	public GarbageCollectCommand setExpire(Date expire) {
 		this.expire = expire;
 		return this;
 	}
 
 	/**
 	 * Whether to use aggressive mode or not. If set to true JGit behaves more
 	 * similar to native git's "git gc --aggressive". If set to
 	 * <code>true</code> compressed objects found in old packs are not reused
 	 * but every object is compressed again. Configuration variables
 	 * pack.window and pack.depth are set to 250 for this GC.
 	 *
 	 * @since 3.6
 	 * @param aggressive
 	 *            whether to turn on or off aggressive mode
 	 * @return this instance
 	 */
 	public GarbageCollectCommand setAggressive(boolean aggressive) {
 		if (aggressive) {
 			StoredConfig repoConfig = repo.getConfig();
 			pconfig.setDeltaSearchWindowSize(repoConfig.getInt(
 					ConfigConstants.CONFIG_GC_SECTION,
 					ConfigConstants.CONFIG_KEY_AGGRESSIVE_WINDOW,
 					DEFAULT_GC_AGGRESSIVE_WINDOW));
 			pconfig.setMaxDeltaDepth(repoConfig.getInt(
 					ConfigConstants.CONFIG_GC_SECTION,
 					ConfigConstants.CONFIG_KEY_AGGRESSIVE_DEPTH,
 					DEFAULT_GC_AGGRESSIVE_DEPTH));
 			pconfig.setReuseObjects(false);
 		} else
 			pconfig = new PackConfig(repo);
 		return this;
 	}
 
 	/**
 	 * Whether to preserve old pack files instead of deleting them.
 	 *
 	 * @since 4.7
 	 * @param preserveOldPacks
 	 *            whether to preserve old pack files
 	 * @return this instance
 	 */
 	public GarbageCollectCommand setPreserveOldPacks(boolean preserveOldPacks) {
 		if (pconfig == null)
 			pconfig = new PackConfig(repo);
 
 		pconfig.setPreserveOldPacks(preserveOldPacks);
 		return this;
 	}
 
 	/**
 	 * Whether to prune preserved pack files in the preserved directory.
 	 *
 	 * @since 4.7
 	 * @param prunePreserved
 	 *            whether to prune preserved pack files
 	 * @return this instance
 	 */
 	public GarbageCollectCommand setPrunePreserved(boolean prunePreserved) {
 		if (pconfig == null)
 			pconfig = new PackConfig(repo);
 
 		pconfig.setPrunePreserved(prunePreserved);
 		return this;
 	}
 
 	/** {@inheritDoc} */
 	@Override
 	public Properties call() throws GitAPIException {
 		checkCallable();
 
 		try {
 			if (repo instanceof FileRepository) {
 				GC gc = new GC((FileRepository) repo);
 				gc.setPackConfig(pconfig);
 				gc.setProgressMonitor(monitor);
 				if (this.expire != null)
 					gc.setExpire(expire);
 
 				try {
 					gc.gc().get();
 					return toProperties(gc.getStatistics());
 				} catch (ParseException | InterruptedException
 						| ExecutionException e) {
 					throw new JGitInternalException(JGitText.get().gcFailed, e);
 				}
 			} else if (repo instanceof DfsRepository) {
 				DfsGarbageCollector gc =
 					new DfsGarbageCollector((DfsRepository) repo);
 				gc.setPackConfig(pconfig);
 				gc.pack(monitor);
 				return new Properties();
 			} else {
 				throw new UnsupportedOperationException(MessageFormat.format(
 						JGitText.get().unsupportedGC,
 						repo.getClass().toString()));
 			}
 		} catch (IOException e) {
 			throw new JGitInternalException(JGitText.get().gcFailed, e);
 		}
 	}
 
 	/**
 	 * Computes and returns the repository statistics.
 	 *
 	 * @return the repository statistics
 	 * @throws org.eclipse.jgit.api.errors.GitAPIException
 	 *             thrown if the repository statistics cannot be computed
 	 * @since 3.0
 	 */
 	public Properties getStatistics() throws GitAPIException {
 		try {
 			if (repo instanceof FileRepository) {
 				GC gc = new GC((FileRepository) repo);
 				return toProperties(gc.getStatistics());
 			}
 			return new Properties();
 		} catch (IOException e) {
 			throw new JGitInternalException(
 					JGitText.get().couldNotGetRepoStatistics, e);
 		}
 	}
 
 	@SuppressWarnings("boxing")
 	private static Properties toProperties(RepoStatistics stats) {
 		Properties p = new Properties();
 		p.put("numberOfBitmaps", stats.numberOfBitmaps); //$NON-NLS-1$
 		p.put("numberOfLooseObjects", stats.numberOfLooseObjects); //$NON-NLS-1$
 		p.put("numberOfLooseRefs", stats.numberOfLooseRefs); //$NON-NLS-1$
 		p.put("numberOfPackedObjects", stats.numberOfPackedObjects); //$NON-NLS-1$
 		p.put("numberOfPackedRefs", stats.numberOfPackedRefs); //$NON-NLS-1$
 		p.put("numberOfPackFiles", stats.numberOfPackFiles); //$NON-NLS-1$
 		p.put("sizeOfLooseObjects", stats.sizeOfLooseObjects); //$NON-NLS-1$
 		p.put("sizeOfPackedObjects", stats.sizeOfPackedObjects); //$NON-NLS-1$
 		return p;
 	}
 }