/*
    * Copyright (C) 2008, Marek Zawirski <marek.zawirski@gmail.com>
    * Copyright (C) 2008, 2022 Shawn O. Pearce <spearce@spearce.org> 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 static org.eclipse.jgit.transport.GitProtocolConstants.CAPABILITY_ATOMIC;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.text.MessageFormat;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  import org.eclipse.jgit.errors.NoRemoteRepositoryException;
  import org.eclipse.jgit.errors.NotSupportedException;
  import org.eclipse.jgit.errors.PackProtocolException;
  import org.eclipse.jgit.errors.TooLargeObjectInPackException;
  import org.eclipse.jgit.errors.TooLargePackException;
  import org.eclipse.jgit.errors.TransportException;
  import org.eclipse.jgit.internal.JGitText;
  import org.eclipse.jgit.internal.storage.pack.PackWriter;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.ProgressMonitor;
  import org.eclipse.jgit.lib.Ref;
  import org.eclipse.jgit.transport.RemoteRefUpdate.Status;
  
  /**
   * Push implementation using the native Git pack transfer service.
   * <p>
   * This is the canonical implementation for transferring objects to the remote
   * repository from the local repository by talking to the 'git-receive-pack'
   * service. Objects are packed on the local side into a pack file and then sent
   * to the remote repository.
   * <p>
   * This connection requires only a bi-directional pipe or socket, and thus is
   * easily wrapped up into a local process pipe, anonymous TCP socket, or a
   * command executed through an SSH tunnel.
   * <p>
   * This implementation honors
   * {@link org.eclipse.jgit.transport.Transport#isPushThin()} option.
   * <p>
   * Concrete implementations should just call
   * {@link #init(java.io.InputStream, java.io.OutputStream)} and
   * {@link #readAdvertisedRefs()} methods in constructor or before any use. They
   * should also handle resources releasing in {@link #close()} method if needed.
   */
  public abstract class BasePackPushConnection extends BasePackConnection implements
  		PushConnection {
  	/**
  	 * The client expects a status report after the server processes the pack.
  	 * @since 2.0
  	 */
  	public static final String CAPABILITY_REPORT_STATUS = GitProtocolConstants.CAPABILITY_REPORT_STATUS;
  
  	/**
  	 * The server supports deleting refs.
  	 * @since 2.0
  	 */
  	public static final String CAPABILITY_DELETE_REFS = GitProtocolConstants.CAPABILITY_DELETE_REFS;
  
  	/**
  	 * The server supports packs with OFS deltas.
  	 * @since 2.0
  	 */
  	public static final String CAPABILITY_OFS_DELTA = GitProtocolConstants.CAPABILITY_OFS_DELTA;
  
  	/**
  	 * The client supports using the 64K side-band for progress messages.
  	 * @since 2.0
  	 */
  	public static final String CAPABILITY_SIDE_BAND_64K = GitProtocolConstants.CAPABILITY_SIDE_BAND_64K;
  
  	/**
  	 * The server supports the receiving of push options.
  	 * @since 4.5
  	 */
  	public static final String CAPABILITY_PUSH_OPTIONS = GitProtocolConstants.CAPABILITY_PUSH_OPTIONS;
  
  	private final boolean thinPack;
  	private final boolean atomic;
  
  	/** A list of option strings associated with this push. */
  	private List<String> pushOptions;
  
  	private boolean capableAtomic;
  	private boolean capableDeleteRefs;
  	private boolean capableReport;
 	private boolean capableSideBand;
 	private boolean capableOfsDelta;
 	private boolean capablePushOptions;
 
 	private boolean sentCommand;
 	private boolean writePack;
 
 	/** Time in milliseconds spent transferring the pack data. */
 	private long packTransferTime;
 
 	/**
 	 * Create a new connection to push using the native git transport.
 	 *
 	 * @param packTransport
 	 *            the transport.
 	 */
 	public BasePackPushConnection(PackTransport packTransport) {
 		super(packTransport);
 		thinPack = transport.isPushThin();
 		atomic = transport.isPushAtomic();
 		pushOptions = transport.getPushOptions();
 	}
 
 	/** {@inheritDoc} */
 	@Override
 	public void push(final ProgressMonitor monitor,
 			final Map<String, RemoteRefUpdate> refUpdates)
 			throws TransportException {
 		push(monitor, refUpdates, null);
 	}
 
 	/** {@inheritDoc} */
 	@Override
 	public void push(final ProgressMonitor monitor,
 			final Map<String, RemoteRefUpdate> refUpdates, OutputStream outputStream)
 			throws TransportException {
 		markStartedOperation();
 		doPush(monitor, refUpdates, outputStream);
 	}
 
 	/** {@inheritDoc} */
 	@Override
 	protected TransportException noRepository(Throwable cause) {
 		// Sadly we cannot tell the "invalid URI" case from "push not allowed".
 		// Opening a fetch connection can help us tell the difference, as any
 		// useful repository is going to support fetch if it also would allow
 		// push. So if fetch throws NoRemoteRepositoryException we know the
 		// URI is wrong. Otherwise we can correctly state push isn't allowed
 		// as the fetch connection opened successfully.
 		//
 		TransportException te;
 		try {
 			transport.openFetch().close();
 			te = new TransportException(uri, JGitText.get().pushNotPermitted);
 		} catch (NoRemoteRepositoryException e) {
 			// Fetch concluded the repository doesn't exist.
 			te = e;
 		} catch (NotSupportedException | TransportException e) {
 			te = new TransportException(uri, JGitText.get().pushNotPermitted, e);
 		}
 		te.addSuppressed(cause);
 		return te;
 	}
 
 	/**
 	 * Push one or more objects and update the remote repository.
 	 *
 	 * @param monitor
 	 *            progress monitor to receive status updates.
 	 * @param refUpdates
 	 *            update commands to be applied to the remote repository.
 	 * @param outputStream
 	 *            output stream to write sideband messages to
 	 * @throws org.eclipse.jgit.errors.TransportException
 	 *             if any exception occurs.
 	 * @since 3.0
 	 */
 	protected void doPush(final ProgressMonitor monitor,
 			final Map<String, RemoteRefUpdate> refUpdates,
 			OutputStream outputStream) throws TransportException {
 		try {
 			writeCommands(refUpdates.values(), monitor, outputStream);
 
 			if (pushOptions != null && capablePushOptions)
 				transmitOptions();
 			if (writePack)
 				writePack(refUpdates, monitor);
 			if (sentCommand) {
 				if (capableReport)
 					readStatusReport(refUpdates);
 				if (capableSideBand) {
 					// Ensure the data channel is at EOF, so we know we have
 					// read all side-band data from all channels and have a
 					// complete copy of the messages (if any) buffered from
 					// the other data channels.
 					//
 					int b = in.read();
 					if (0 <= b) {
 						throw new TransportException(uri, MessageFormat.format(
 								JGitText.get().expectedEOFReceived,
 								Character.valueOf((char) b)));
 					}
 				}
 			}
 		} catch (TransportException e) {
 			throw e;
 		} catch (Exception e) {
 			throw new TransportException(uri, e.getMessage(), e);
 		} finally {
 			if (in instanceof SideBandInputStream) {
 				((SideBandInputStream) in).drainMessages();
 			}
 			close();
 		}
 	}
 
 	private void writeCommands(final Collection<RemoteRefUpdate> refUpdates,
 			final ProgressMonitor monitor, OutputStream outputStream) throws IOException {
 		final String capabilities = enableCapabilities(monitor, outputStream);
 		if (atomic && !capableAtomic) {
 			throw new TransportException(uri,
 					JGitText.get().atomicPushNotSupported);
 		}
 
 		if (pushOptions != null && !capablePushOptions) {
 			throw new TransportException(uri,
 					MessageFormat.format(JGitText.get().pushOptionsNotSupported,
 							pushOptions.toString()));
 		}
 
 		for (RemoteRefUpdate rru : refUpdates) {
 			if (!capableDeleteRefs && rru.isDelete()) {
 				rru.setStatus(Status.REJECTED_NODELETE);
 				continue;
 			}
 
 			final StringBuilder sb = new StringBuilder();
 			ObjectId oldId = rru.getExpectedOldObjectId();
 			if (oldId == null) {
 				final Ref advertised = getRef(rru.getRemoteName());
 				oldId = advertised != null ? advertised.getObjectId() : null;
 				if (oldId == null) {
 					oldId = ObjectId.zeroId();
 				}
 			}
 			sb.append(oldId.name());
 			sb.append(' ');
 			sb.append(rru.getNewObjectId().name());
 			sb.append(' ');
 			sb.append(rru.getRemoteName());
 			if (!sentCommand) {
 				sentCommand = true;
 				sb.append(capabilities);
 			}
 
 			pckOut.writeString(sb.toString());
 			rru.setStatus(Status.AWAITING_REPORT);
 			if (!rru.isDelete())
 				writePack = true;
 		}
 
 		if (monitor.isCancelled())
 			throw new TransportException(uri, JGitText.get().pushCancelled);
 		pckOut.end();
 		outNeedsEnd = false;
 	}
 
 	private void transmitOptions() throws IOException {
 		for (String pushOption : pushOptions) {
 			pckOut.writeString(pushOption);
 		}
 
 		pckOut.end();
 	}
 
 	private String enableCapabilities(final ProgressMonitor monitor,
 			OutputStream outputStream) {
 		final StringBuilder line = new StringBuilder();
 		if (atomic)
 			capableAtomic = wantCapability(line, CAPABILITY_ATOMIC);
 		capableReport = wantCapability(line, CAPABILITY_REPORT_STATUS);
 		capableDeleteRefs = wantCapability(line, CAPABILITY_DELETE_REFS);
 		capableOfsDelta = wantCapability(line, CAPABILITY_OFS_DELTA);
 
 		if (pushOptions != null) {
 			capablePushOptions = wantCapability(line, CAPABILITY_PUSH_OPTIONS);
 		}
 
 		capableSideBand = wantCapability(line, CAPABILITY_SIDE_BAND_64K);
 		if (capableSideBand) {
 			in = new SideBandInputStream(in, monitor, getMessageWriter(),
 					outputStream);
 			pckIn = new PacketLineIn(in);
 		}
 		addUserAgentCapability(line);
 
 		if (line.length() > 0)
 			line.setCharAt(0, '\0');
 		return line.toString();
 	}
 
 	private void writePack(final Map<String, RemoteRefUpdate> refUpdates,
 			final ProgressMonitor monitor) throws IOException {
 		Set<ObjectId> remoteObjects = new HashSet<>();
 		Set<ObjectId> newObjects = new HashSet<>();
 
 		try (PackWriter writer = new PackWriter(transport.getPackConfig(),
 				local.newObjectReader())) {
 
 			for (Ref r : getRefs()) {
 				// only add objects that we actually have
 				ObjectId oid = r.getObjectId();
 				if (local.getObjectDatabase().has(oid))
 					remoteObjects.add(oid);
 			}
 			remoteObjects.addAll(additionalHaves);
 			for (RemoteRefUpdate r : refUpdates.values()) {
 				if (!ObjectId.zeroId().equals(r.getNewObjectId()))
 					newObjects.add(r.getNewObjectId());
 			}
 
 			writer.setIndexDisabled(true);
 			writer.setUseCachedPacks(true);
 			writer.setUseBitmaps(true);
 			writer.setThin(thinPack);
 			writer.setReuseValidatingObjects(false);
 			writer.setDeltaBaseAsOffset(capableOfsDelta);
 			writer.preparePack(monitor, newObjects, remoteObjects);
 
 			OutputStream packOut = out;
 			if (capableSideBand) {
 				packOut = new CheckingSideBandOutputStream(in, out);
 			}
 			writer.writePack(monitor, monitor, packOut);
 
 			packTransferTime = writer.getStatistics().getTimeWriting();
 		}
 	}
 
 	private void readStatusReport(Map<String, RemoteRefUpdate> refUpdates)
 			throws IOException {
 		final String unpackLine = readStringLongTimeout();
 		if (!unpackLine.startsWith("unpack ")) //$NON-NLS-1$
 			throw new PackProtocolException(uri, MessageFormat
 					.format(JGitText.get().unexpectedReportLine, unpackLine));
 		final String unpackStatus = unpackLine.substring("unpack ".length()); //$NON-NLS-1$
 		if (unpackStatus.startsWith("error Pack exceeds the limit of")) {//$NON-NLS-1$
 			throw new TooLargePackException(uri,
 					unpackStatus.substring("error ".length())); //$NON-NLS-1$
 		} else if (unpackStatus.startsWith("error Object too large")) {//$NON-NLS-1$
 			throw new TooLargeObjectInPackException(uri,
 					unpackStatus.substring("error ".length())); //$NON-NLS-1$
 		} else if (!unpackStatus.equals("ok")) { //$NON-NLS-1$
 			throw new TransportException(uri, MessageFormat.format(
 					JGitText.get().errorOccurredDuringUnpackingOnTheRemoteEnd, unpackStatus));
 		}
 
 		for (String refLine : pckIn.readStrings()) {
 			boolean ok = false;
 			int refNameEnd = -1;
 			if (refLine.startsWith("ok ")) { //$NON-NLS-1$
 				ok = true;
 				refNameEnd = refLine.length();
 			} else if (refLine.startsWith("ng ")) { //$NON-NLS-1$
 				ok = false;
 				refNameEnd = refLine.indexOf(' ', 3);
 			}
 			if (refNameEnd == -1)
 				throw new PackProtocolException(MessageFormat.format(JGitText.get().unexpectedReportLine2
 						, uri, refLine));
 			final String refName = refLine.substring(3, refNameEnd);
 			final String message = (ok ? null : refLine
 					.substring(refNameEnd + 1));
 
 			final RemoteRefUpdate rru = refUpdates.get(refName);
 			if (rru == null)
 				throw new PackProtocolException(MessageFormat.format(JGitText.get().unexpectedRefReport, uri, refName));
 			if (ok) {
 				rru.setStatus(Status.OK);
 			} else {
 				rru.setStatus(Status.REJECTED_OTHER_REASON);
 				rru.setMessage(message);
 			}
 		}
 		for (RemoteRefUpdate rru : refUpdates.values()) {
 			if (rru.getStatus() == Status.AWAITING_REPORT)
 				throw new PackProtocolException(MessageFormat.format(
 						JGitText.get().expectedReportForRefNotReceived , uri, rru.getRemoteName()));
 		}
 	}
 
 	private String readStringLongTimeout() throws IOException {
 		if (timeoutIn == null)
 			return pckIn.readString();
 
 		// The remote side may need a lot of time to choke down the pack
 		// we just sent them. There may be many deltas that need to be
 		// resolved by the remote. Its hard to say how long the other
 		// end is going to be silent. Taking 10x the configured timeout
 		// or the time spent transferring the pack, whichever is larger,
 		// gives the other side some reasonable window to process the data,
 		// but this is just a wild guess.
 		//
 		final int oldTimeout = timeoutIn.getTimeout();
 		final int sendTime = (int) Math.min(packTransferTime, 28800000L);
 		try {
 			int timeout = 10 * Math.max(sendTime, oldTimeout);
 			timeoutIn.setTimeout((timeout < 0) ? Integer.MAX_VALUE : timeout);
 			return pckIn.readString();
 		} finally {
 			timeoutIn.setTimeout(oldTimeout);
 		}
 	}
 
 	/**
 	 * Gets the list of option strings associated with this push.
 	 *
 	 * @return pushOptions
 	 * @since 4.5
 	 */
 	public List<String> getPushOptions() {
 		return pushOptions;
 	}
 
 	private static class CheckingSideBandOutputStream extends OutputStream {
 		private final InputStream in;
 		private final OutputStream out;
 
 		CheckingSideBandOutputStream(InputStream in, OutputStream out) {
 			this.in = in;
 			this.out = out;
 		}
 
 		@Override
 		public void write(int b) throws IOException {
 			write(new byte[] { (byte) b });
 		}
 
 		@Override
 		public void write(byte[] buf, int ptr, int cnt) throws IOException {
 			try {
 				out.write(buf, ptr, cnt);
 			} catch (IOException e) {
 				throw checkError(e);
 			}
 		}
 
 		@Override
 		public void flush() throws IOException {
 			try {
 				out.flush();
 			} catch (IOException e) {
 				throw checkError(e);
 			}
 		}
 
 		private IOException checkError(IOException e1) {
 			try {
 				in.read();
 			} catch (TransportException e2) {
 				return e2;
 			} catch (IOException e2) {
 				return e1;
 			}
 			return e1;
 		}
 	}
 }