/*
 * Copyright (C) 2010, Chris Aniszczyk <caniszczyk@gmail.com>
 * and other copyright owners as documented in the project's IP log.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
 * available at http://www.eclipse.org/org/documents/edl-v10.php
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * - Neither the name of the Eclipse Foundation, Inc. nor the
 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.eclipse.jgit.api;

import static java.util.stream.Collectors.toList;

import java.io.IOException;
import java.net.URISyntaxException;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.eclipse.jgit.annotations.Nullable;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.api.errors.InvalidConfigurationException;
import org.eclipse.jgit.api.errors.InvalidRemoteException;
import org.eclipse.jgit.api.errors.JGitInternalException;
import org.eclipse.jgit.errors.ConfigInvalidException;
import org.eclipse.jgit.errors.NoRemoteRepositoryException;
import org.eclipse.jgit.errors.NotSupportedException;
import org.eclipse.jgit.errors.TransportException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.ConfigConstants;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.NullProgressMonitor;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ProgressMonitor;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.lib.StoredConfig;
import org.eclipse.jgit.lib.SubmoduleConfig.FetchRecurseSubmodulesMode;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.submodule.SubmoduleWalk;
import org.eclipse.jgit.transport.FetchResult;
import org.eclipse.jgit.transport.RefSpec;
import org.eclipse.jgit.transport.TagOpt;
import org.eclipse.jgit.transport.Transport;

/**
 * A class used to execute a {@code Fetch} command. It has setters for all
 * supported options and arguments of this command and a {@link #call()} method
 * to finally execute the command.
 *
 * @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-fetch.html"
 *      >Git documentation about Fetch</a>
 */
public class FetchCommand extends TransportCommand<FetchCommand, FetchResult> {
	private String remote = Constants.DEFAULT_REMOTE_NAME;

	private List<RefSpec> refSpecs;

	private ProgressMonitor monitor = NullProgressMonitor.INSTANCE;

	private boolean checkFetchedObjects;

	private Boolean removeDeletedRefs;

	private boolean dryRun;

	private boolean thin = Transport.DEFAULT_FETCH_THIN;

	private TagOpt tagOption;

	private FetchRecurseSubmodulesMode submoduleRecurseMode = null;

	private Callback callback;

	/**
	 * Callback for status of fetch operation.
	 *
	 * @since 4.8
	 *
	 */
	public interface Callback {
		/**
		 * Notify fetching a submodule.
		 *
		 * @param name
		 *            the submodule name.
		 */
		void fetchingSubmodule(String name);
	}

	/**
	 * @param repo
	 */
	protected FetchCommand(Repository repo) {
		super(repo);
		refSpecs = new ArrayList<>(3);
	}

	private FetchRecurseSubmodulesMode getRecurseMode(String path) {
		// Use the caller-specified mode, if set
		if (submoduleRecurseMode != null) {
			return submoduleRecurseMode;
		}

		// Fall back to submodule.name.fetchRecurseSubmodules, if set
		FetchRecurseSubmodulesMode mode = repo.getConfig().getEnum(
				FetchRecurseSubmodulesMode.values(),
				ConfigConstants.CONFIG_SUBMODULE_SECTION, path,
				ConfigConstants.CONFIG_KEY_FETCH_RECURSE_SUBMODULES, null);
		if (mode != null) {
			return mode;
		}

		// Fall back to fetch.recurseSubmodules, if set
		mode = repo.getConfig().getEnum(FetchRecurseSubmodulesMode.values(),
				ConfigConstants.CONFIG_FETCH_SECTION, null,
				ConfigConstants.CONFIG_KEY_RECURSE_SUBMODULES, null);
		if (mode != null) {
			return mode;
		}

		// Default to on-demand mode
		return FetchRecurseSubmodulesMode.ON_DEMAND;
	}

	private void fetchSubmodules(FetchResult results)
			throws org.eclipse.jgit.api.errors.TransportException,
			GitAPIException, InvalidConfigurationException {
		try (SubmoduleWalk walk = new SubmoduleWalk(repo);
				RevWalk revWalk = new RevWalk(repo)) {
			// Walk over submodules in the parent repository's FETCH_HEAD.
			ObjectId fetchHead = repo.resolve(Constants.FETCH_HEAD);
			if (fetchHead == null) {
				return;
			}
			walk.setTree(revWalk.parseTree(fetchHead));
			while (walk.next()) {
				Repository submoduleRepo = walk.getRepository();

				// Skip submodules that don't exist locally (have not been
				// cloned), are not registered in the .gitmodules file, or
				// not registered in the parent repository's config.
				if (submoduleRepo == null || walk.getModulesPath() == null
						|| walk.getConfigUrl() == null) {
					continue;
				}

				FetchRecurseSubmodulesMode recurseMode = getRecurseMode(
						walk.getPath());

				// When the fetch mode is "yes" we always fetch. When the mode
				// is "on demand", we only fetch if the submodule's revision was
				// updated to an object that is not currently present in the
				// submodule.
				if ((recurseMode == FetchRecurseSubmodulesMode.ON_DEMAND
						&& !submoduleRepo.hasObject(walk.getObjectId()))
						|| recurseMode == FetchRecurseSubmodulesMode.YES) {
					FetchCommand f = new FetchCommand(submoduleRepo)
							.setProgressMonitor(monitor).setTagOpt(tagOption)
							.setCheckFetchedObjects(checkFetchedObjects)
							.setRemoveDeletedRefs(isRemoveDeletedRefs())
							.setThin(thin).setRefSpecs(refSpecs)
							.setDryRun(dryRun)
							.setRecurseSubmodules(recurseMode);
					configure(f);
					if (callback != null) {
						callback.fetchingSubmodule(walk.getPath());
					}
					results.addSubmodule(walk.getPath(), f.call());
				}
			}
		} catch (IOException e) {
			throw new JGitInternalException(e.getMessage(), e);
		} catch (ConfigInvalidException e) {
			throw new InvalidConfigurationException(e.getMessage(), e);
		}
	}

	/**
	 * Executes the {@code fetch} command with all the options and parameters
	 * collected by the setter methods of this class. Each instance of this
	 * class should only be used for one invocation of the command (means: one
	 * call to {@link #call()})
	 *
	 * @return a {@link FetchResult} object representing the successful fetch
	 *         result
	 * @throws InvalidRemoteException
	 *             when called with an invalid remote uri
	 * @throws org.eclipse.jgit.api.errors.TransportException
	 *             when an error occurs during transport
	 */
	@Override
	public FetchResult call() throws GitAPIException, InvalidRemoteException,
			org.eclipse.jgit.api.errors.TransportException {
		checkCallable();

		try (Transport transport = Transport.open(repo, remote)) {
			transport.setCheckFetchedObjects(checkFetchedObjects);
			transport.setRemoveDeletedRefs(isRemoveDeletedRefs());
			transport.setDryRun(dryRun);
			if (tagOption != null)
				transport.setTagOpt(tagOption);
			transport.setFetchThin(thin);
			configure(transport);

			FetchResult result = transport.fetch(monitor, refSpecs);
			if (!repo.isBare()) {
				fetchSubmodules(result);
			}

			return result;
		} catch (NoRemoteRepositoryException e) {
			throw new InvalidRemoteException(MessageFormat.format(
					JGitText.get().invalidRemote, remote), e);
		} catch (TransportException e) {
			throw new org.eclipse.jgit.api.errors.TransportException(
					e.getMessage(), e);
		} catch (URISyntaxException e) {
			throw new InvalidRemoteException(MessageFormat.format(
					JGitText.get().invalidRemote, remote));
		} catch (NotSupportedException e) {
			throw new JGitInternalException(
					JGitText.get().exceptionCaughtDuringExecutionOfFetchCommand,
					e);
		}

	}

	/**
	 * Set the mode to be used for recursing into submodules.
	 *
	 * @param recurse
	 *            corresponds to the
	 *            --recurse-submodules/--no-recurse-submodules options. If
	 *            {@code null} use the value of the
	 *            {@code submodule.name.fetchRecurseSubmodules} option
	 *            configured per submodule. If not specified there, use the
	 *            value of the {@code fetch.recurseSubmodules} option configured
	 *            in git config. If not configured in either, "on-demand" is the
	 *            built-in default.
	 * @return {@code this}
	 * @since 4.7
	 */
	public FetchCommand setRecurseSubmodules(
			@Nullable FetchRecurseSubmodulesMode recurse) {
		checkCallable();
		submoduleRecurseMode = recurse;
		return this;
	}

	/**
	 * The remote (uri or name) used for the fetch operation. If no remote is
	 * set, the default value of <code>Constants.DEFAULT_REMOTE_NAME</code> will
	 * be used.
	 *
	 * @see Constants#DEFAULT_REMOTE_NAME
	 * @param remote
	 * @return {@code this}
	 */
	public FetchCommand setRemote(String remote) {
		checkCallable();
		this.remote = remote;
		return this;
	}

	/**
	 * @return the remote used for the remote operation
	 */
	public String getRemote() {
		return remote;
	}

	/**
	 * @return the timeout used for the fetch operation
	 */
	public int getTimeout() {
		return timeout;
	}

	/**
	 * @return whether to check received objects checked for validity
	 */
	public boolean isCheckFetchedObjects() {
		return checkFetchedObjects;
	}

	/**
	 * If set to true, objects received will be checked for validity
	 *
	 * @param checkFetchedObjects
	 * @return {@code this}
	 */
	public FetchCommand setCheckFetchedObjects(boolean checkFetchedObjects) {
		checkCallable();
		this.checkFetchedObjects = checkFetchedObjects;
		return this;
	}

	/**
	 * @return whether or not to remove refs which no longer exist in the source
	 */
	public boolean isRemoveDeletedRefs() {
		if (removeDeletedRefs != null)
			return removeDeletedRefs.booleanValue();
		else { // fall back to configuration
			boolean result = false;
			StoredConfig config = repo.getConfig();
			result = config.getBoolean(ConfigConstants.CONFIG_FETCH_SECTION,
					null, ConfigConstants.CONFIG_KEY_PRUNE, result);
			result = config.getBoolean(ConfigConstants.CONFIG_REMOTE_SECTION,
					remote, ConfigConstants.CONFIG_KEY_PRUNE, result);
			return result;
		}
	}

	/**
	 * If set to true, refs are removed which no longer exist in the source
	 *
	 * @param removeDeletedRefs
	 * @return {@code this}
	 */
	public FetchCommand setRemoveDeletedRefs(boolean removeDeletedRefs) {
		checkCallable();
		this.removeDeletedRefs = Boolean.valueOf(removeDeletedRefs);
		return this;
	}

	/**
	 * @return the progress monitor for the fetch operation
	 */
	public ProgressMonitor getProgressMonitor() {
		return monitor;
	}

	/**
	 * The progress monitor associated with the fetch operation. By default,
	 * this is set to <code>NullProgressMonitor</code>
	 *
	 * @see NullProgressMonitor
	 *
	 * @param monitor
	 * @return {@code this}
	 */
	public FetchCommand setProgressMonitor(ProgressMonitor monitor) {
		checkCallable();
		if (monitor == null) {
			monitor = NullProgressMonitor.INSTANCE;
		}
		this.monitor = monitor;
		return this;
	}

	/**
	 * @return the ref specs
	 */
	public List<RefSpec> getRefSpecs() {
		return refSpecs;
	}

	/**
	 * The ref specs to be used in the fetch operation
	 *
	 * @param specs
	 * @return {@code this}
	 * @since 4.9
	 */
	public FetchCommand setRefSpecs(String... specs) {
		return setRefSpecs(
				Arrays.stream(specs).map(RefSpec::new).collect(toList()));
	}

	/**
	 * The ref specs to be used in the fetch operation
	 *
	 * @param specs
	 * @return {@code this}
	 */
	public FetchCommand setRefSpecs(RefSpec... specs) {
		return setRefSpecs(Arrays.asList(specs));
	}

	/**
	 * The ref specs to be used in the fetch operation
	 *
	 * @param specs
	 * @return {@code this}
	 */
	public FetchCommand setRefSpecs(List<RefSpec> specs) {
		checkCallable();
		this.refSpecs.clear();
		this.refSpecs.addAll(specs);
		return this;
	}

	/**
	 * @return the dry run preference for the fetch operation
	 */
	public boolean isDryRun() {
		return dryRun;
	}

	/**
	 * Sets whether the fetch operation should be a dry run
	 *
	 * @param dryRun
	 * @return {@code this}
	 */
	public FetchCommand setDryRun(boolean dryRun) {
		checkCallable();
		this.dryRun = dryRun;
		return this;
	}

	/**
	 * @return the thin-pack preference for fetch operation
	 */
	public boolean isThin() {
		return thin;
	}

	/**
	 * Sets the thin-pack preference for fetch operation.
	 *
	 * Default setting is Transport.DEFAULT_FETCH_THIN
	 *
	 * @param thin
	 * @return {@code this}
	 */
	public FetchCommand setThin(boolean thin) {
		checkCallable();
		this.thin = thin;
		return this;
	}

	/**
	 * Sets the specification of annotated tag behavior during fetch
	 *
	 * @param tagOpt
	 * @return {@code this}
	 */
	public FetchCommand setTagOpt(TagOpt tagOpt) {
		checkCallable();
		this.tagOption = tagOpt;
		return this;
	}

	/**
	 * Register a progress callback.
	 *
	 * @param callback
	 *            the callback
	 * @return {@code this}
	 * @since 4.8
	 */
	public FetchCommand setCallback(Callback callback) {
		this.callback = callback;
		return this;
	}
}