/*
    * Copyright (C) 2017, Google Inc. 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.pgm.debug;
  
  import java.io.FileInputStream;
  import java.io.IOException;
  
  import org.eclipse.jgit.internal.storage.io.BlockSource;
  import org.eclipse.jgit.internal.storage.reftable.RefCursor;
  import org.eclipse.jgit.internal.storage.reftable.ReftableReader;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.Ref;
  import org.eclipse.jgit.pgm.Command;
  import org.eclipse.jgit.pgm.TextBuiltin;
  import org.kohsuke.args4j.Argument;
  
  @Command
  class ReadReftable extends TextBuiltin {
  	@Argument(index = 0)
  	private String input;
  
  	@Argument(index = 1, required = false)
  	private String ref;
  
  	/** {@inheritDoc} */
  	@Override
  	protected void run() throws Exception {
  		try (FileInputStream in = new FileInputStream(input);
  				BlockSource src = BlockSource.from(in);
  				ReftableReader reader = new ReftableReader(src)) {
  			try (RefCursor rc = ref != null
  					? reader.seekRefsWithPrefix(ref)
  					: reader.allRefs()) {
  				while (rc.next()) {
  					write(rc.getRef());
  				}
  			}
  		}
  	}
  
  	private void write(Ref r) throws IOException {
  		if (r.isSymbolic()) {
  			outw.println(r.getTarget().getName() + '\t' + r.getName());
  			return;
  		}
  
  		ObjectId id1 = r.getObjectId();
  		if (id1 != null) {
  			outw.println(id1.name() + '\t' + r.getName());
  		}
  
  		ObjectId id2 = r.getPeeledObjectId();
  		if (id2 != null) {
  			outw.println('^' + id2.name());
  		}
  	}
  }