/*
 * Copyright (C) 2008, Marek Zawirski <marek.zawirski@gmail.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.transport;

import java.io.IOException;
import java.io.OutputStream;
import java.text.MessageFormat;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.errors.NotSupportedException;
import org.eclipse.jgit.errors.TransportException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ProgressMonitor;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevObject;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.transport.RemoteRefUpdate.Status;

Class performing push operation on remote repository.
See Also:
push.push(ProgressMonitor, Collection, OutputStream)/**
 * Class performing push operation on remote repository.
 *
 * @see Transport#push(ProgressMonitor, Collection, OutputStream)
 */
class PushProcess {
	
Task name for ProgressMonitor used during opening connection. /** Task name for {@link ProgressMonitor} used during opening connection. */
	static final String PROGRESS_OPENING_CONNECTION = JGitText.get().openingConnection;

	
Transport used to perform this operation. /** Transport used to perform this operation. */
	private final Transport transport;

	
Push operation connection created to perform this operation /** Push operation connection created to perform this operation */
	private PushConnection connection;

	
Refs to update on remote side. /** Refs to update on remote side. */
	private final Map<String, RemoteRefUpdate> toPush;

	
Revision walker for checking some updates properties. /** Revision walker for checking some updates properties. */
	private final RevWalk walker;

	
an outputstream to write messages to /** an outputstream to write messages to */
	private final OutputStream out;

	
A list of option strings associated with this push /** A list of option strings associated with this push */
	private List<String> pushOptions;

	
Create process for specified transport and refs updates specification.
Params:
transport – 
           transport between remote and local repository, used to create
           connection.
toPush – 
           specification of refs updates (and local tracking branches).
Throws:
TransportException – /**
	 * Create process for specified transport and refs updates specification.
	 *
	 * @param transport
	 *            transport between remote and local repository, used to create
	 *            connection.
	 * @param toPush
	 *            specification of refs updates (and local tracking branches).
	 *
	 * @throws TransportException
	 */
	PushProcess(final Transport transport,
			final Collection<RemoteRefUpdate> toPush) throws TransportException {
		this(transport, toPush, null);
	}

	
Create process for specified transport and refs updates specification.
Params:
transport – 
           transport between remote and local repository, used to create
           connection.
toPush – 
           specification of refs updates (and local tracking branches).
out – 
           OutputStream to write messages to
Throws:
TransportException – /**
	 * Create process for specified transport and refs updates specification.
	 *
	 * @param transport
	 *            transport between remote and local repository, used to create
	 *            connection.
	 * @param toPush
	 *            specification of refs updates (and local tracking branches).
	 * @param out
	 *            OutputStream to write messages to
	 * @throws TransportException
	 */
	PushProcess(final Transport transport,
			final Collection<RemoteRefUpdate> toPush, OutputStream out)
			throws TransportException {
		this.walker = new RevWalk(transport.local);
		this.transport = transport;
		this.toPush = new LinkedHashMap<>();
		this.out = out;
		this.pushOptions = transport.getPushOptions();
		for (RemoteRefUpdate rru : toPush) {
			if (this.toPush.put(rru.getRemoteName(), rru) != null)
				throw new TransportException(MessageFormat.format(
						JGitText.get().duplicateRemoteRefUpdateIsIllegal, rru.getRemoteName()));
		}
	}

	
Perform push operation between local and remote repository - set remote
refs appropriately, send needed objects and update local tracking refs.
 When Transport.isDryRun() is true, result of this operation is just estimation of real operation result, no real action is performed. 
Params:
monitor – 
           progress monitor used for feedback about operation.
Throws:
NotSupportedException – 
            when push operation is not supported by provided transport.
TransportException – 
            when some error occurred during operation, like I/O, protocol
            error, or local database consistency error.
Returns:
result of push operation with complete status description./**
	 * Perform push operation between local and remote repository - set remote
	 * refs appropriately, send needed objects and update local tracking refs.
	 * <p>
	 * When {@link Transport#isDryRun()} is true, result of this operation is
	 * just estimation of real operation result, no real action is performed.
	 *
	 * @param monitor
	 *            progress monitor used for feedback about operation.
	 * @return result of push operation with complete status description.
	 * @throws NotSupportedException
	 *             when push operation is not supported by provided transport.
	 * @throws TransportException
	 *             when some error occurred during operation, like I/O, protocol
	 *             error, or local database consistency error.
	 */
	PushResult execute(ProgressMonitor monitor)
			throws NotSupportedException, TransportException {
		try {
			monitor.beginTask(PROGRESS_OPENING_CONNECTION,
					ProgressMonitor.UNKNOWN);

			final PushResult res = new PushResult();
			connection = transport.openPush();
			try {
				res.setAdvertisedRefs(transport.getURI(), connection
						.getRefsMap());
				res.peerUserAgent = connection.getPeerUserAgent();
				res.setRemoteUpdates(toPush);
				monitor.endTask();

				final Map<String, RemoteRefUpdate> preprocessed = prepareRemoteUpdates();
				if (transport.isDryRun())
					modifyUpdatesForDryRun();
				else if (!preprocessed.isEmpty())
					connection.push(monitor, preprocessed, out);
			} finally {
				connection.close();
				res.addMessages(connection.getMessages());
			}
			if (!transport.isDryRun())
				updateTrackingRefs();
			for (RemoteRefUpdate rru : toPush.values()) {
				final TrackingRefUpdate tru = rru.getTrackingRefUpdate();
				if (tru != null)
					res.add(tru);
			}
			return res;
		} finally {
			walker.close();
		}
	}

	private Map<String, RemoteRefUpdate> prepareRemoteUpdates()
			throws TransportException {
		boolean atomic = transport.isPushAtomic();
		final Map<String, RemoteRefUpdate> result = new LinkedHashMap<>();
		for (RemoteRefUpdate rru : toPush.values()) {
			final Ref advertisedRef = connection.getRef(rru.getRemoteName());
			ObjectId advertisedOld = null;
			if (advertisedRef != null) {
				advertisedOld = advertisedRef.getObjectId();
			}
			if (advertisedOld == null) {
				advertisedOld = ObjectId.zeroId();
			}

			if (rru.getNewObjectId().equals(advertisedOld)) {
				if (rru.isDelete()) {
					// ref does exist neither locally nor remotely
					rru.setStatus(Status.NON_EXISTING);
				} else {
					// same object - nothing to do
					rru.setStatus(Status.UP_TO_DATE);
				}
				continue;
			}

			// caller has explicitly specified expected old object id, while it
			// has been changed in the mean time - reject
			if (rru.isExpectingOldObjectId()
					&& !rru.getExpectedOldObjectId().equals(advertisedOld)) {
				rru.setStatus(Status.REJECTED_REMOTE_CHANGED);
				if (atomic) {
					return rejectAll();
				}
				continue;
			}
			if (!rru.isExpectingOldObjectId()) {
				rru.setExpectedOldObjectId(advertisedOld);
			}

			// create ref (hasn't existed on remote side) and delete ref
			// are always fast-forward commands, feasible at this level
			if (advertisedOld.equals(ObjectId.zeroId()) || rru.isDelete()) {
				rru.setFastForward(true);
				result.put(rru.getRemoteName(), rru);
				continue;
			}

			// check for fast-forward:
			// - both old and new ref must point to commits, AND
			// - both of them must be known for us, exist in repository, AND
			// - old commit must be ancestor of new commit
			boolean fastForward = true;
			try {
				RevObject oldRev = walker.parseAny(advertisedOld);
				final RevObject newRev = walker.parseAny(rru.getNewObjectId());
				if (!(oldRev instanceof RevCommit)
						|| !(newRev instanceof RevCommit)
						|| !walker.isMergedInto((RevCommit) oldRev,
								(RevCommit) newRev))
					fastForward = false;
			} catch (MissingObjectException x) {
				fastForward = false;
			} catch (Exception x) {
				throw new TransportException(transport.getURI(), MessageFormat.format(
						JGitText.get().readingObjectsFromLocalRepositoryFailed, x.getMessage()), x);
			}
			rru.setFastForward(fastForward);
			if (!fastForward && !rru.isForceUpdate()) {
				rru.setStatus(Status.REJECTED_NONFASTFORWARD);
				if (atomic) {
					return rejectAll();
				}
			} else {
				result.put(rru.getRemoteName(), rru);
			}
		}
		return result;
	}

	private Map<String, RemoteRefUpdate> rejectAll() {
		for (RemoteRefUpdate rru : toPush.values()) {
			if (rru.getStatus() == Status.NOT_ATTEMPTED) {
				rru.setStatus(RemoteRefUpdate.Status.REJECTED_OTHER_REASON);
				rru.setMessage(JGitText.get().transactionAborted);
			}
		}
		return Collections.emptyMap();
	}

	private void modifyUpdatesForDryRun() {
		for (RemoteRefUpdate rru : toPush.values())
			if (rru.getStatus() == Status.NOT_ATTEMPTED)
				rru.setStatus(Status.OK);
	}

	private void updateTrackingRefs() {
		for (RemoteRefUpdate rru : toPush.values()) {
			final Status status = rru.getStatus();
			if (rru.hasTrackingRefUpdate()
					&& (status == Status.UP_TO_DATE || status == Status.OK)) {
				// update local tracking branch only when there is a chance that
				// it has changed; this is possible for:
				// -updated (OK) status,
				// -up to date (UP_TO_DATE) status
				try {
					rru.updateTrackingRef(walker);
				} catch (IOException e) {
					// ignore as RefUpdate has stored I/O error status
				}
			}
		}
	}

	
Gets the list of option strings associated with this push.
Returns:
pushOptions
Since:
4.5/**
	 * Gets the list of option strings associated with this push.
	 *
	 * @return pushOptions
	 * @since 4.5
	 */
	public List<String> getPushOptions() {
		return pushOptions;
	}
}