/*
    * Copyright (C) 2017, Markus Duft <markus.duft@ssi-schaefer.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.lfs;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintStream;
  
  import org.eclipse.jgit.annotations.Nullable;
  import org.eclipse.jgit.attributes.Attribute;
  import org.eclipse.jgit.hooks.PrePushHook;
  import org.eclipse.jgit.lib.ConfigConstants;
  import org.eclipse.jgit.lib.ObjectLoader;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.util.LfsFactory;
  
  /**
   * Implementation of {@link LfsFactory}, using built-in (optional) LFS support.
   *
   * @since 4.11
   */
  public class BuiltinLFS extends LfsFactory {
  
  	private BuiltinLFS() {
  		SmudgeFilter.register();
  		CleanFilter.register();
  	}
  
  	/**
  	 * Activates the built-in LFS support.
  	 */
  	public static void register() {
  		setInstance(new BuiltinLFS());
  	}
  
  	@Override
  	public boolean isAvailable() {
  		return true;
  	}
  
  	@Override
  	public ObjectLoaderlib/ObjectLoader.html#ObjectLoader">ObjectLoader applySmudgeFilter(Repository db, ObjectLoader loader,
  			Attribute attribute) throws IOException {
  		if (isEnabled(db) && (attribute == null || isEnabled(db, attribute))) {
  			return LfsBlobFilter.smudgeLfsBlob(db, loader);
  		}
  		return loader;
  	}
  
  	@Override
  	public LfsInputStream applyCleanFilter(Repository db, InputStream input,
  			long length, Attribute attribute) throws IOException {
  		if (isEnabled(db, attribute)) {
  			return new LfsInputStream(LfsBlobFilter.cleanLfsBlob(db, input));
  		}
  		return new LfsInputStream(input, length);
  	}
  
  	@Override
  	@Nullable
  	public PrePushHook getPrePushHook(Repository repo,
  			PrintStream outputStream) {
  		if (isEnabled(repo)) {
  			return new LfsPrePushHook(repo, outputStream);
  		}
  		return null;
  	}
  
  	@Override
  	@Nullable
  	public PrePushHook getPrePushHook(Repository repo, PrintStream outputStream,
  			PrintStream errorStream) {
  		if (isEnabled(repo)) {
  			return new LfsPrePushHook(repo, outputStream, errorStream);
  		}
  		return null;
  	}
  
  	/**
  	 * @param db
  	 *            the repository
  	 * @return whether LFS is requested for the given repo.
  	 */
  	@Override
  	public boolean isEnabled(Repository db) {
  		if (db == null) {
  			return false;
  		}
  		return db.getConfig().getBoolean(ConfigConstants.CONFIG_FILTER_SECTION,
  				ConfigConstants.CONFIG_SECTION_LFS,
  				ConfigConstants.CONFIG_KEY_USEJGITBUILTIN,
  				false);
 	}
 
 	/**
 	 * @param db
 	 *            the repository
 	 * @param attribute
 	 *            the attribute to check
 	 * @return whether LFS filter is enabled for the given .gitattribute
 	 *         attribute.
 	 */
 	private boolean isEnabled(Repository db, Attribute attribute) {
 		if (attribute == null) {
 			return false;
 		}
 		return isEnabled(db) && ConfigConstants.CONFIG_SECTION_LFS
 				.equals(attribute.getValue());
 	}
 
 	@Override
 	public LfsInstallCommand getInstallCommand() {
 		return new InstallBuiltinLfsCommand();
 	}
 
 }