/*
    * Copyright (C) 2010, Garmin International
    * Copyright (C) 2010, Matt Fischer <matt.fischer@garmin.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.revwalk;
  
  import java.io.IOException;
  import java.util.Collections;
  import java.util.List;
  import java.util.Objects;
  
  import org.eclipse.jgit.errors.IncorrectObjectTypeException;
  import org.eclipse.jgit.errors.MissingObjectException;
  import org.eclipse.jgit.lib.AnyObjectId;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.ObjectReader;
  import org.eclipse.jgit.lib.Repository;
  
  /**
   * Interface for revision walkers that perform depth filtering.
   */
  public interface DepthWalk {
  	/**
  	 * Get depth to filter to.
  	 *
  	 * @return Depth to filter to.
  	 */
  	int getDepth();
  
  	/**
  	 * @return the deepen-since value; if not 0, this walk only returns commits
  	 *         whose commit time is at or after this limit
  	 * @since 5.2
  	 */
  	default int getDeepenSince() {
  		return 0;
  	}
  
  	/**
  	 * @return the objects specified by the client using --shallow-exclude
  	 * @since 5.2
  	 */
  	default List<ObjectId> getDeepenNots() {
  		return Collections.emptyList();
  	}
  
  	/** @return flag marking commits that should become unshallow. */
  	/**
  	 * Get flag marking commits that should become unshallow.
  	 *
  	 * @return flag marking commits that should become unshallow.
  	 */
  	RevFlag getUnshallowFlag();
  
  	/**
  	 * Get flag marking commits that are interesting again.
  	 *
  	 * @return flag marking commits that are interesting again.
  	 */
  	RevFlag getReinterestingFlag();
  
  	/**
  	 * @return flag marking commits that are to be excluded because of --shallow-exclude
  	 * @since 5.2
  	 */
  	RevFlag getDeepenNotFlag();
  
  	/** RevCommit with a depth (in commits) from a root. */
  	public static class Commit extends RevCommit {
  		/** Depth of this commit in the graph, via shortest path. */
  		int depth;
  
  		boolean isBoundary;
  
  		/**
  		 * True if this commit was excluded due to a shallow fetch
  		 * setting. All its children are thus boundary commits.
  		 */
  		boolean makesChildBoundary;
  
  		/** @return depth of this commit, as found by the shortest path. */
  		public int getDepth() {
  			return depth;
  		}
  
  		/**
  		 * @return true if at least one of this commit's parents was excluded
  		 *         due to a shallow fetch setting, false otherwise
  		 * @since 5.2
  		 */
  		public boolean isBoundary() {
  			return isBoundary;
 		}
 
 		/**
 		 * Initialize a new commit.
 		 *
 		 * @param id
 		 *            object name for the commit.
 		 */
 		protected Commit(AnyObjectId id) {
 			super(id);
 			depth = -1;
 		}
 	}
 
 	/** Subclass of RevWalk that performs depth filtering. */
 	public class RevWalk extends org.eclipse.jgit.revwalk.RevWalk implements DepthWalk {
 		private final int depth;
 
 		private int deepenSince;
 
 		private List<ObjectId> deepenNots;
 
 		private final RevFlag UNSHALLOW;
 
 		private final RevFlag REINTERESTING;
 
 		private final RevFlag DEEPEN_NOT;
 
 		/**
 		 * @param repo Repository to walk
 		 * @param depth Maximum depth to return
 		 */
 		public RevWalk(Repository repo, int depth) {
 			super(repo);
 
 			this.depth = depth;
 			this.deepenNots = Collections.emptyList();
 			this.UNSHALLOW = newFlag("UNSHALLOW"); //$NON-NLS-1$
 			this.REINTERESTING = newFlag("REINTERESTING"); //$NON-NLS-1$
 			this.DEEPEN_NOT = newFlag("DEEPEN_NOT"); //$NON-NLS-1$
 		}
 
 		/**
 		 * @param or ObjectReader to use
 		 * @param depth Maximum depth to return
 		 */
 		public RevWalk(ObjectReader or, int depth) {
 			super(or);
 
 			this.depth = depth;
 			this.deepenNots = Collections.emptyList();
 			this.UNSHALLOW = newFlag("UNSHALLOW"); //$NON-NLS-1$
 			this.REINTERESTING = newFlag("REINTERESTING"); //$NON-NLS-1$
 			this.DEEPEN_NOT = newFlag("DEEPEN_NOT"); //$NON-NLS-1$
 		}
 
 		/**
 		 * Mark a root commit (i.e., one whose depth should be considered 0.)
 		 *
 		 * @param c
 		 *            Commit to mark
 		 * @throws IOException
 		 * @throws IncorrectObjectTypeException
 		 * @throws MissingObjectException
 		 */
 		public void markRoot(RevCommit c) throws MissingObjectException,
 				IncorrectObjectTypeException, IOException {
 			if (c instanceof Commit)
 				((Commit) c).depth = 0;
 			super.markStart(c);
 		}
 
 		@Override
 		protected RevCommit createCommit(AnyObjectId id) {
 			return new Commit(id);
 		}
 
 		@Override
 		public int getDepth() {
 			return depth;
 		}
 
 		@Override
 		public int getDeepenSince() {
 			return deepenSince;
 		}
 
 		/**
 		 * Sets the deepen-since value.
 		 *
 		 * @param limit
 		 *            new deepen-since value
 		 * @since 5.2
 		 */
 		public void setDeepenSince(int limit) {
 			deepenSince = limit;
 		}
 
 		@Override
 		public List<ObjectId> getDeepenNots() {
 			return deepenNots;
 		}
 
 		/**
 		 * Mark objects that the client specified using
 		 * --shallow-exclude. Objects that are not commits have no
 		 * effect.
 		 *
 		 * @param deepenNots specified objects
 		 * @since 5.2
 		 */
 		public void setDeepenNots(List<ObjectId> deepenNots) {
 			this.deepenNots = Objects.requireNonNull(deepenNots);
 		}
 
 		@Override
 		public RevFlag getUnshallowFlag() {
 			return UNSHALLOW;
 		}
 
 		@Override
 		public RevFlag getReinterestingFlag() {
 			return REINTERESTING;
 		}
 
 		@Override
 		public RevFlag getDeepenNotFlag() {
 			return DEEPEN_NOT;
 		}
 
 		/**
 		 * @since 4.5
 		 */
 		@Override
 		public ObjectWalk toObjectWalkWithSameObjects() {
 			ObjectWalk ow = new ObjectWalk(reader, depth);
 			ow.deepenSince = deepenSince;
 			ow.deepenNots = deepenNots;
 			ow.objects = objects;
 			ow.freeFlags = freeFlags;
 			return ow;
 		}
 	}
 
 	/** Subclass of ObjectWalk that performs depth filtering. */
 	public class ObjectWalk extends org.eclipse.jgit.revwalk.ObjectWalk implements DepthWalk {
 		private final int depth;
 
 		private int deepenSince;
 
 		private List<ObjectId> deepenNots;
 
 		private final RevFlag UNSHALLOW;
 
 		private final RevFlag REINTERESTING;
 
 		private final RevFlag DEEPEN_NOT;
 
 		/**
 		 * @param repo Repository to walk
 		 * @param depth Maximum depth to return
 		 */
 		public ObjectWalk(Repository repo, int depth) {
 			super(repo);
 
 			this.depth = depth;
 			this.deepenNots = Collections.emptyList();
 			this.UNSHALLOW = newFlag("UNSHALLOW"); //$NON-NLS-1$
 			this.REINTERESTING = newFlag("REINTERESTING"); //$NON-NLS-1$
 			this.DEEPEN_NOT = newFlag("DEEPEN_NOT"); //$NON-NLS-1$
 		}
 
 		/**
 		 * @param or Object Reader
 		 * @param depth Maximum depth to return
 		 */
 		public ObjectWalk(ObjectReader or, int depth) {
 			super(or);
 
 			this.depth = depth;
 			this.deepenNots = Collections.emptyList();
 			this.UNSHALLOW = newFlag("UNSHALLOW"); //$NON-NLS-1$
 			this.REINTERESTING = newFlag("REINTERESTING"); //$NON-NLS-1$
 			this.DEEPEN_NOT = newFlag("DEEPEN_NOT"); //$NON-NLS-1$
 		}
 
 		/**
 		 * Mark a root commit (i.e., one whose depth should be considered 0.)
 		 *
 		 * @param o
 		 *            Commit to mark
 		 * @throws IOException
 		 * @throws IncorrectObjectTypeException
 		 * @throws MissingObjectException
 		 */
 		public void markRoot(RevObject o) throws MissingObjectException,
 				IncorrectObjectTypeException, IOException {
 			RevObject c = o;
 			while (c instanceof RevTag) {
 				c = ((RevTag) c).getObject();
 				parseHeaders(c);
 			}
 			if (c instanceof Commit)
 				((Commit) c).depth = 0;
 			super.markStart(o);
 		}
 
 		/**
 		 * Mark an element which used to be shallow in the client, but which
 		 * should now be considered a full commit. Any ancestors of this commit
 		 * should be included in the walk, even if they are the ancestor of an
 		 * uninteresting commit.
 		 *
 		 * @param c
 		 *            Commit to mark
 		 * @throws MissingObjectException
 		 * @throws IncorrectObjectTypeException
 		 * @throws IOException
 		 */
 		public void markUnshallow(RevObject c) throws MissingObjectException,
 				IncorrectObjectTypeException, IOException {
 			if (c instanceof RevCommit)
 				c.add(UNSHALLOW);
 			super.markStart(c);
 		}
 
 		@Override
 		protected RevCommit createCommit(AnyObjectId id) {
 			return new Commit(id);
 		}
 
 		@Override
 		public int getDepth() {
 			return depth;
 		}
 
 		@Override
 		public int getDeepenSince() {
 			return deepenSince;
 		}
 
 		@Override
 		public List<ObjectId> getDeepenNots() {
 			return deepenNots;
 		}
 
 		@Override
 		public RevFlag getUnshallowFlag() {
 			return UNSHALLOW;
 		}
 
 		@Override
 		public RevFlag getReinterestingFlag() {
 			return REINTERESTING;
 		}
 
 		@Override
 		public RevFlag getDeepenNotFlag() {
 			return DEEPEN_NOT;
 		}
 	}
 }