package com.gitblit.utils;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;

import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.diff.DiffEntry;
import org.eclipse.jgit.diff.DiffEntry.ChangeType;
import org.eclipse.jgit.diff.DiffFormatter;
import org.eclipse.jgit.diff.RawTextComparator;
import org.eclipse.jgit.errors.ConfigInvalidException;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.errors.StopWalkException;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.FileMode;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectLoader;
import org.eclipse.jgit.lib.PersonIdent;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.lib.StoredConfig;
import org.eclipse.jgit.revwalk.RevBlob;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevObject;
import org.eclipse.jgit.revwalk.RevSort;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.revwalk.filter.RevFilter;
import org.eclipse.jgit.treewalk.TreeWalk;
import org.eclipse.jgit.treewalk.filter.AndTreeFilter;
import org.eclipse.jgit.treewalk.filter.OrTreeFilter;
import org.eclipse.jgit.treewalk.filter.PathFilter;
import org.eclipse.jgit.treewalk.filter.PathFilterGroup;
import org.eclipse.jgit.treewalk.filter.PathSuffixFilter;
import org.eclipse.jgit.treewalk.filter.TreeFilter;
import org.eclipse.jgit.util.io.DisabledOutputStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.gitblit.wicket.models.Metric;
import com.gitblit.wicket.models.PathModel;
import com.gitblit.wicket.models.PathModel.PathChangeModel;
import com.gitblit.wicket.models.RefModel;
import com.gitblit.wicket.models.TicketModel;
import com.gitblit.wicket.models.TicketModel.Comment;

public class JGitUtils {

	/** Prefix for notes refs */
	public static final String R_NOTES = "refs/notes/";

	/** Standard notes ref */
	public static final String R_NOTES_COMMITS = R_NOTES + "commits";

	private final static Logger LOGGER = LoggerFactory.getLogger(JGitUtils.class);

	public static Repository createRepository(File repositoriesFolder, String name, boolean bare) {
		Git git = Git.init().setDirectory(new File(repositoriesFolder, name)).setBare(bare).call();
		return git.getRepository();
	}

	public static List<String> getRepositoryList(File repositoriesFolder, boolean exportAll, boolean readNested) {
		List<String> list = new ArrayList<String>();
		list.addAll(getNestedRepositories(repositoriesFolder, repositoriesFolder, exportAll, readNested));
		Collections.sort(list);
		return list;
	}

	public static List<String> getNestedRepositories(File repositoriesFolder, File folder, boolean exportAll, boolean readNested) {
		String basefile = repositoriesFolder.getAbsolutePath();
		List<String> list = new ArrayList<String>();
		for (File file : folder.listFiles()) {
			if (file.isDirectory() && !file.getName().equalsIgnoreCase(Constants.DOT_GIT)) {
				// if this is a git repository add it to the list
				//
				// first look for standard folder/.git structure
				File gitFolder = new File(file, Constants.DOT_GIT);
				boolean isGitRepository = gitFolder.exists() && gitFolder.isDirectory();

				// then look for folder.git/HEAD or folder/HEAD and
				// folder/config
				if (!isGitRepository) {
					if ((file.getName().endsWith(Constants.DOT_GIT_EXT) && new File(file, Constants.HEAD).exists()) || (new File(file, "config").exists() && new File(file, Constants.HEAD).exists())) {
						gitFolder = file;
						isGitRepository = true;
					}
				}
				boolean exportRepository = isGitRepository && (exportAll || new File(gitFolder, "git-daemon-export-ok").exists());

				if (exportRepository) {
					// determine repository name relative to repositories folder
					String filename = file.getAbsolutePath();
					String repo = filename.substring(basefile.length()).replace('\\', '/');
					if (repo.charAt(0) == '/') {
						repo = repo.substring(1);
					}
					list.add(repo);
				}

				// look for nested repositories
				if (readNested) {
					list.addAll(getNestedRepositories(repositoriesFolder, file, exportAll, readNested));
				}
			}
		}
		return list;
	}

	public static RevCommit getFirstCommit(Repository r, String branch) {
		if (!hasCommits(r)) {
			return null;
		}
		if (StringUtils.isEmpty(branch)) {
			branch = Constants.HEAD;
		}
		try {
			RevWalk walk = new RevWalk(r);
			walk.sort(RevSort.REVERSE);
			RevCommit head = walk.parseCommit(r.resolve(branch));
			walk.markStart(head);
			RevCommit commit = walk.next();
			walk.dispose();
			return commit;
		} catch (Throwable t) {
			LOGGER.error("Failed to determine first commit", t);
		}
		return null;
	}

	public static Date getFirstChange(Repository r, String branch) {
		try {
			RevCommit commit = getFirstCommit(r, branch);
			if (commit == null) {
				// fresh repository
				return new Date(r.getDirectory().lastModified());
			}
			return getCommitDate(commit);
		} catch (Throwable t) {
			LOGGER.error("Failed to determine first change", t);
		}
		return null;
	}

	public static boolean hasCommits(Repository r) {
		return new File(r.getDirectory(), Constants.R_HEADS).list().length > 0;
	}

	public static Date getLastChange(Repository r) {
		if (!hasCommits(r)) {
			// fresh repository
			return new Date(r.getDirectory().lastModified());
		}
		RevCommit commit = getCommit(r, Constants.HEAD);
		return getCommitDate(commit);
	}

	public static RevCommit getCommit(Repository r, String objectId) {
		RevCommit commit = null;
		if (!hasCommits(r)) {
			return null;
		}
		try {
			if (objectId == null || objectId.trim().length() == 0) {
				objectId = Constants.HEAD;
			}
			ObjectId object = r.resolve(objectId);
			RevWalk walk = new RevWalk(r);
			RevCommit rev = walk.parseCommit(object);
			commit = rev;
			walk.dispose();
		} catch (Throwable t) {
			LOGGER.error("Failed to get commit " + objectId, t);
		}
		return commit;
	}

	public static Map<ObjectId, List<String>> getAllRefs(Repository r) {
		Map<ObjectId, List<String>> refs = new HashMap<ObjectId, List<String>>();
		Map<AnyObjectId, Set<Ref>> allRefs = r.getAllRefsByPeeledObjectId();
		for (AnyObjectId id : allRefs.keySet()) {
			List<String> list = new ArrayList<String>();
			for (Ref setRef : allRefs.get(id)) {
				String name = setRef.getName();
				list.add(name);
			}
			refs.put(id.toObjectId(), list);
		}
		return refs;
	}

	public static Map<ObjectId, List<String>> getRefs(Repository r, String baseRef) {
		Map<ObjectId, List<String>> refs = new HashMap<ObjectId, List<String>>();
		Map<AnyObjectId, Set<Ref>> allRefs = r.getAllRefsByPeeledObjectId();
		for (AnyObjectId id : allRefs.keySet()) {
			List<String> list = new ArrayList<String>();
			for (Ref setRef : allRefs.get(id)) {
				String name = setRef.getName();
				if (name.startsWith(baseRef)) {
					list.add(name);
				}
			}
			refs.put(id.toObjectId(), list);
		}
		return refs;
	}

	/**
	 * Lookup an entry stored in a tree, failing if not present.
	 * 
	 * @param tree
	 *            the tree to search.
	 * @param path
	 *            the path to find the entry of.
	 * @return the parsed object entry at this path
	 * @throws Exception
	 */
	public static RevObject getRevObject(Repository r, final RevTree tree, final String path) {
		RevObject ro = null;
		RevWalk rw = new RevWalk(r);
		TreeWalk tw = new TreeWalk(r);
		tw.setFilter(PathFilterGroup.createFromStrings(Collections.singleton(path)));
		try {
			tw.reset(tree);
			while (tw.next()) {
				if (tw.isSubtree() && !path.equals(tw.getPathString())) {
					tw.enterSubtree();
					continue;
				}
				ObjectId entid = tw.getObjectId(0);
				FileMode entmode = tw.getFileMode(0);
				ro = rw.lookupAny(entid, entmode.getObjectType());
				rw.parseBody(ro);
			}
		} catch (Throwable t) {
			LOGGER.error("Can't find " + path + " in tree " + tree.name(), t);
		} finally {
			if (rw != null) {
				rw.dispose();
			}
		}
		return ro;
	}

	public static byte[] getRawContent(Repository r, RevBlob blob) {
		ByteArrayOutputStream os = new ByteArrayOutputStream();
		try {
			ObjectLoader ldr = r.open(blob.getId(), Constants.OBJ_BLOB);
			byte[] tmp = new byte[1024];
			InputStream in = ldr.openStream();
			int n;
			while ((n = in.read(tmp)) > 0) {
				os.write(tmp, 0, n);
			}
			in.close();
		} catch (Throwable t) {
			LOGGER.error("Failed to read raw content", t);
		}
		return os.toByteArray();
	}

	public static String getRawContentAsString(Repository r, RevBlob blob) {
		byte[] content = getRawContent(r, blob);
		return new String(content, Charset.forName(Constants.CHARACTER_ENCODING));
	}

	public static String getRawContentAsString(Repository r, RevCommit commit, String blobPath) {
		RevObject obj = getRevObject(r, commit.getTree(), blobPath);
		byte[] content = getRawContent(r, (RevBlob) obj);
		return new String(content, Charset.forName(Constants.CHARACTER_ENCODING));
	}

	public static List<PathModel> getFilesInPath(Repository r, String basePath, String objectId) {
		RevCommit commit = getCommit(r, objectId);
		return getFilesInPath(r, basePath, commit);
	}

	public static List<PathModel> getFilesInPath(Repository r, String basePath, RevCommit commit) {
		List<PathModel> list = new ArrayList<PathModel>();
		if (commit == null) {
			return list;
		}
		final TreeWalk walk = new TreeWalk(r);
		try {
			walk.addTree(commit.getTree());
			if (basePath != null && basePath.length() > 0) {
				PathFilter f = PathFilter.create(basePath);
				walk.setFilter(f);
				walk.setRecursive(false);
				boolean foundFolder = false;
				while (walk.next()) {
					if (!foundFolder && walk.isSubtree()) {
						walk.enterSubtree();
					}
					if (walk.getPathString().equals(basePath)) {
						foundFolder = true;
						continue;
					}
					if (foundFolder) {
						list.add(getPathModel(walk, basePath, commit));
					}
				}
			} else {
				walk.setRecursive(false);
				while (walk.next()) {
					list.add(getPathModel(walk, null, commit));
				}
			}
		} catch (IOException e) {
			LOGGER.error("Failed to get files for commit " + commit.getName(), e);
		} finally {
			walk.release();
		}
		Collections.sort(list);
		return list;
	}

	public static List<PathChangeModel> getFilesInCommit(Repository r, String commitId) {
		RevCommit commit = getCommit(r, commitId);
		return getFilesInCommit(r, commit);
	}

	public static List<PathChangeModel> getFilesInCommit(Repository r, RevCommit commit) {
		List<PathChangeModel> list = new ArrayList<PathChangeModel>();
		if (commit == null) {
			LOGGER.warn("getFilesInCommit for NULL commit");
			return list;
		}
		try {
			final RevWalk rw = new RevWalk(r);
			RevCommit parent = rw.parseCommit(commit.getParent(0).getId());
			RevTree parentTree = parent.getTree();
			RevTree commitTree = commit.getTree();

			final TreeWalk walk = new TreeWalk(r);
			walk.reset();
			walk.setRecursive(true);
			walk.addTree(parentTree);
			walk.addTree(commitTree);
			walk.setFilter(TreeFilter.ANY_DIFF);

			RawTextComparator cmp = RawTextComparator.DEFAULT;
			DiffFormatter df = new DiffFormatter(DisabledOutputStream.INSTANCE);
			df.setRepository(r);
			df.setDiffComparator(cmp);
			df.setDetectRenames(true);
			List<DiffEntry> diffs = df.scan(parentTree, commitTree);
			for (DiffEntry diff : diffs) {
				if (diff.getChangeType().equals(ChangeType.DELETE)) {
					list.add(new PathChangeModel(diff.getOldPath(), diff.getOldPath(), 0, diff.getNewMode().getBits(), commit.getId().getName(), diff.getChangeType()));
				} else {
					list.add(new PathChangeModel(diff.getNewPath(), diff.getNewPath(), 0, diff.getNewMode().getBits(), commit.getId().getName(), diff.getChangeType()));
				}
			}
		} catch (Throwable t) {
			LOGGER.error("failed to determine files in commit!", t);
		}
		return list;
	}

	public static List<PathModel> getDocuments(Repository r, List<String> extensions) {
		List<PathModel> list = new ArrayList<PathModel>();
		RevCommit commit = getCommit(r, Constants.HEAD);
		final TreeWalk walk = new TreeWalk(r);
		try {
			walk.addTree(commit.getTree());
			if (extensions != null && extensions.size() > 0) {
				Collection<TreeFilter> suffixFilters = new ArrayList<TreeFilter>();
				for (String extension : extensions) {
					if (extension.charAt(0) == '.') {
						suffixFilters.add(PathSuffixFilter.create(extension));
					} else {
						// escape the . since this is a regexp filter
						suffixFilters.add(PathSuffixFilter.create("\\." + extension));
					}
				}
				TreeFilter filter = OrTreeFilter.create(suffixFilters);
				walk.setFilter(filter);
				walk.setRecursive(true);
				while (walk.next()) {
					list.add(getPathModel(walk, null, commit));
				}
			} else {
				while (walk.next()) {
					list.add(getPathModel(walk, null, commit));
				}
			}
		} catch (IOException e) {
			LOGGER.error("Failed to get files for commit " + commit.getName(), e);
		} finally {
			walk.release();
		}
		Collections.sort(list);
		return list;
	}

	public static Map<ChangeType, AtomicInteger> getChangedPathsStats(List<PathChangeModel> paths) {
		Map<ChangeType, AtomicInteger> stats = new HashMap<ChangeType, AtomicInteger>();
		for (PathChangeModel path : paths) {
			if (!stats.containsKey(path.changeType)) {
				stats.put(path.changeType, new AtomicInteger(0));
			}
			stats.get(path.changeType).incrementAndGet();
		}
		return stats;
	}

	public static enum DiffOutputType {
		PLAIN, GITWEB, GITBLIT;

		public static DiffOutputType forName(String name) {
			for (DiffOutputType type : values()) {
				if (type.name().equalsIgnoreCase(name)) {
					return type;
				}
			}
			return null;
		}
	}

	public static String getCommitDiff(Repository r, RevCommit commit, DiffOutputType outputType) {
		return getCommitDiff(r, null, commit, null, outputType);
	}

	public static String getCommitDiff(Repository r, RevCommit commit, String path, DiffOutputType outputType) {
		return getCommitDiff(r, null, commit, path, outputType);
	}

	public static String getCommitDiff(Repository r, RevCommit baseCommit, RevCommit commit, DiffOutputType outputType) {
		return getCommitDiff(r, baseCommit, commit, null, outputType);
	}

	public static String getCommitDiff(Repository r, RevCommit baseCommit, RevCommit commit, String path, DiffOutputType outputType) {
		try {
			RevTree baseTree;
			if (baseCommit == null) {
				final RevWalk rw = new RevWalk(r);
				RevCommit parent = rw.parseCommit(commit.getParent(0).getId());
				rw.dispose();
				baseTree = parent.getTree();
			} else {
				baseTree = baseCommit.getTree();
			}

			RevTree commitTree = commit.getTree();

			final TreeWalk walk = new TreeWalk(r);
			walk.reset();
			walk.setRecursive(true);
			walk.addTree(baseTree);
			walk.addTree(commitTree);
			walk.setFilter(TreeFilter.ANY_DIFF);

			final ByteArrayOutputStream os = new ByteArrayOutputStream();
			RawTextComparator cmp = RawTextComparator.DEFAULT;
			DiffFormatter df;
			switch (outputType) {
			case GITWEB:
				df = new GitWebDiffFormatter(os);
				break;
			case GITBLIT:
				df = new GitBlitDiffFormatter(os);
				break;
			case PLAIN:
			default:
				df = new DiffFormatter(os);
				break;
			}
			df.setRepository(r);
			df.setDiffComparator(cmp);
			df.setDetectRenames(true);
			List<DiffEntry> diffs = df.scan(baseTree, commitTree);
			if (path != null && path.length() > 0) {
				for (DiffEntry diff : diffs) {
					if (diff.getNewPath().equalsIgnoreCase(path)) {
						df.format(diff);
						break;
					}
				}
			} else {
				df.format(diffs);
			}
			String diff;
			if (df instanceof GitWebDiffFormatter) {
				// workaround for complex private methods in DiffFormatter
				diff = ((GitWebDiffFormatter) df).getHtml();
			} else {
				diff = os.toString();
			}
			df.flush();
			return diff;
		} catch (Throwable t) {
			LOGGER.error("failed to generate commit diff!", t);
		}
		return null;
	}

	public static String getCommitPatch(Repository r, RevCommit commit) {
		return getCommitPatch(r, commit);
	}

	public static String getCommitPatch(Repository r, RevCommit commit, String path) {
		return getCommitPatch(r, null, commit, path);
	}

	public static String getCommitPatch(Repository r, RevCommit baseCommit, RevCommit commit, String path) {
		try {
			RevTree baseTree;
			if (baseCommit == null) {
				final RevWalk rw = new RevWalk(r);
				RevCommit parent = rw.parseCommit(commit.getParent(0).getId());
				baseTree = parent.getTree();
			} else {
				baseTree = baseCommit.getTree();
			}
			RevTree commitTree = commit.getTree();

			final TreeWalk walk = new TreeWalk(r);
			walk.reset();
			walk.setRecursive(true);
			walk.addTree(baseTree);
			walk.addTree(commitTree);
			walk.setFilter(TreeFilter.ANY_DIFF);

			final ByteArrayOutputStream os = new ByteArrayOutputStream();
			RawTextComparator cmp = RawTextComparator.DEFAULT;
			PatchFormatter df = new PatchFormatter(os);
			df.setRepository(r);
			df.setDiffComparator(cmp);
			df.setDetectRenames(true);
			List<DiffEntry> diffs = df.scan(baseTree, commitTree);
			if (path != null && path.length() > 0) {
				for (DiffEntry diff : diffs) {
					if (diff.getNewPath().equalsIgnoreCase(path)) {
						df.format(diff);
						break;
					}
				}
			} else {
				df.format(diffs);
			}
			String diff = df.getPatch(commit);
			df.flush();
			return diff;
		} catch (Throwable t) {
			LOGGER.error("failed to generate commit diff!", t);
		}
		return null;
	}

	private static PathModel getPathModel(TreeWalk walk, String basePath, RevCommit commit) {
		String name;
		long size = 0;
		if (basePath == null) {
			name = walk.getPathString();
		} else {
			try {
				name = walk.getPathString().substring(basePath.length() + 1);
			} catch (Throwable t) {
				name = walk.getPathString();
			}
		}
		try {
			if (!walk.isSubtree()) {
				size = walk.getObjectReader().getObjectSize(walk.getObjectId(0), Constants.OBJ_BLOB);
			}
		} catch (Throwable t) {
			LOGGER.error("Failed to retrieve blob size", t);
		}
		return new PathModel(name, walk.getPathString(), size, walk.getFileMode(0).getBits(), commit.getName());
	}

	public static String getPermissionsFromMode(int mode) {
		if (FileMode.TREE.equals(mode)) {
			return "drwxr-xr-x";
		} else if (FileMode.REGULAR_FILE.equals(mode)) {
			return "-rw-r--r--";
		} else if (FileMode.EXECUTABLE_FILE.equals(mode)) {
			return "-rwxr-xr-x";
		} else if (FileMode.SYMLINK.equals(mode)) {
			// FIXME symlink permissions
			return "symlink";
		} else if (FileMode.GITLINK.equals(mode)) {
			// FIXME gitlink permissions
			return "gitlink";
		} else if (FileMode.MISSING.equals(mode)) {
			// FIXME missing permissions
			return "missing";
		}
		return "" + mode;
	}

	public static boolean isTreeFromMode(int mode) {
		return FileMode.TREE.equals(mode);
	}

	public static List<RevCommit> getRevLog(Repository r, int maxCount) {
		return getRevLog(r, Constants.HEAD, 0, maxCount);
	}

	public static List<RevCommit> getRevLog(Repository r, String objectId, int offset, int maxCount) {
		return getRevLog(r, objectId, null, offset, maxCount);
	}

	public static List<RevCommit> getRevLog(Repository r, String objectId, String path, int offset, int maxCount) {
		List<RevCommit> list = new ArrayList<RevCommit>();
		if (!hasCommits(r)) {
			return list;
		}
		try {
			if (objectId == null || objectId.trim().length() == 0) {
				objectId = Constants.HEAD;
			}
			RevWalk walk = new RevWalk(r);
			ObjectId object = r.resolve(objectId);
			walk.markStart(walk.parseCommit(object));
			if (!StringUtils.isEmpty(path)) {
				TreeFilter filter = AndTreeFilter.create(PathFilterGroup.createFromStrings(Collections.singleton(path)), TreeFilter.ANY_DIFF);
				walk.setTreeFilter(filter);
			}
			Iterable<RevCommit> revlog = walk;
			if (offset > 0) {
				int count = 0;
				for (RevCommit rev : revlog) {
					count++;
					if (count > offset) {
						list.add(rev);
						if (maxCount > 0 && list.size() == maxCount) {
							break;
						}
					}
				}
			} else {
				for (RevCommit rev : revlog) {
					list.add(rev);
					if (maxCount > 0 && list.size() == maxCount) {
						break;
					}
				}
			}
			walk.dispose();
		} catch (Throwable t) {
			LOGGER.error("Failed to determine last change", t);
		}
		return list;
	}

	public static enum SearchType {
		AUTHOR, COMMITTER, COMMIT;

		public static SearchType forName(String name) {
			for (SearchType type : values()) {
				if (type.name().equalsIgnoreCase(name)) {
					return type;
				}
			}
			return null;
		}

		public String toString() {
			return name().toLowerCase();
		}
	}

	public static List<RevCommit> searchRevlogs(Repository r, String objectId, String value, final SearchType type, int offset, int maxCount) {
		final String lcValue = value.toLowerCase();
		List<RevCommit> list = new ArrayList<RevCommit>();
		if (!hasCommits(r)) {
			return list;
		}
		try {
			if (objectId == null || objectId.trim().length() == 0) {
				objectId = Constants.HEAD;
			}
			RevWalk walk = new RevWalk(r);
			walk.setRevFilter(new RevFilter() {

				@Override
				public RevFilter clone() {
					return this;
				}

				@Override
				public boolean include(RevWalk walker, RevCommit commit) throws StopWalkException, MissingObjectException, IncorrectObjectTypeException, IOException {
					switch (type) {
					case AUTHOR:
						return (commit.getAuthorIdent().getName().toLowerCase().indexOf(lcValue) > -1) || (commit.getAuthorIdent().getEmailAddress().toLowerCase().indexOf(lcValue) > -1);
					case COMMITTER:
						return (commit.getCommitterIdent().getName().toLowerCase().indexOf(lcValue) > -1) || (commit.getCommitterIdent().getEmailAddress().toLowerCase().indexOf(lcValue) > -1);
					case COMMIT:
						return commit.getFullMessage().toLowerCase().indexOf(lcValue) > -1;
					}
					return false;
				}

			});
			ObjectId object = r.resolve(objectId);
			walk.markStart(walk.parseCommit(object));
			Iterable<RevCommit> revlog = walk;
			if (offset > 0) {
				int count = 0;
				for (RevCommit rev : revlog) {
					count++;
					if (count > offset) {
						list.add(rev);
						if (maxCount > 0 && list.size() == maxCount) {
							break;
						}
					}
				}
			} else {
				for (RevCommit rev : revlog) {
					list.add(rev);
					if (maxCount > 0 && list.size() == maxCount) {
						break;
					}
				}
			}
			walk.dispose();
		} catch (Throwable t) {
			LOGGER.error("Failed to determine last change", t);
		}
		return list;
	}

	public static List<RefModel> getTags(Repository r, int maxCount) {
		return getRefs(r, Constants.R_TAGS, maxCount);
	}

	public static List<RefModel> getLocalBranches(Repository r, int maxCount) {
		return getRefs(r, Constants.R_HEADS, maxCount);
	}

	public static List<RefModel> getRemoteBranches(Repository r, int maxCount) {
		return getRefs(r, Constants.R_REMOTES, maxCount);
	}

	public static List<RefModel> getRefs(Repository r, String refs, int maxCount) {
		List<RefModel> list = new ArrayList<RefModel>();
		try {
			Map<String, Ref> map = r.getRefDatabase().getRefs(refs);
			for (String name : map.keySet()) {
				Ref ref = map.get(name);
				RevCommit commit = getCommit(r, ref.getObjectId().getName());
				list.add(new RefModel(name, ref, commit));
			}
			Collections.sort(list);
			Collections.reverse(list);
			if (maxCount > 0 && list.size() > maxCount) {
				list = new ArrayList<RefModel>(list.subList(0, maxCount));
			}
		} catch (IOException e) {
			LOGGER.error("Failed to retrieve " + refs, e);
		}
		return list;
	}

	public static Ref getRef(Repository r, String id) {
		try {
			Map<String, Ref> map = r.getRefDatabase().getRefs(id);
			for (String name : map.keySet()) {
				return map.get(name);
			}
		} catch (IOException e) {
			LOGGER.error("Failed to retrieve ref " + id, e);
		}
		return null;
	}

	public static Date getCommitDate(RevCommit commit) {
		return new Date(commit.getCommitTime() * 1000l);
	}

	public static String getDisplayName(PersonIdent person) {
		final StringBuilder r = new StringBuilder();
		r.append(person.getName());
		r.append(" <");
		r.append(person.getEmailAddress());
		r.append(">");
		return r.toString();
	}

	public static StoredConfig readConfig(Repository r) {
		StoredConfig c = r.getConfig();
		if (c != null) {
			try {
				c.load();
			} catch (ConfigInvalidException cex) {
				LOGGER.error("Repository configuration is invalid!", cex);
			} catch (IOException cex) {
				LOGGER.error("Could not open repository configuration!", cex);
			}
			return c;
		}
		return null;
	}

	public static List<Metric> getDateMetrics(Repository r) {
		Metric total = new Metric("TOTAL");
		final Map<String, Metric> metricMap = new HashMap<String, Metric>();
		
		if (hasCommits(r)) {
			final List<RefModel> tags = getTags(r, -1);
			final Map<ObjectId, RefModel> tagMap = new HashMap<ObjectId, RefModel>();
			for (RefModel tag : tags) {
				tagMap.put(tag.getCommitId(), tag);
			}
			try {
				RevWalk walk = new RevWalk(r);
				ObjectId object = r.resolve(Constants.HEAD);

				RevCommit firstCommit = getFirstCommit(r, Constants.HEAD);
				RevCommit lastCommit = walk.parseCommit(object);
				int diffDays = (lastCommit.getCommitTime() - firstCommit.getCommitTime()) / (60 * 60 * 24);
				total.duration = diffDays;
				DateFormat df;
				if (diffDays <= 90) {
					// Days
					df = new SimpleDateFormat("yyyy-MM-dd");
				} else if (diffDays > 90 && diffDays < 365) {
					// Weeks
					df = new SimpleDateFormat("yyyy-MM (w)");
				} else {
					// Months
					df = new SimpleDateFormat("yyyy-MM");
				}
				walk.markStart(lastCommit);

				Iterable<RevCommit> revlog = walk;
				for (RevCommit rev : revlog) {
					Date d = getCommitDate(rev);
					String p = df.format(d);
					if (!metricMap.containsKey(p))
						metricMap.put(p, new Metric(p));
					Metric m = metricMap.get(p);
					m.count++;
					total.count++;
					if (tagMap.containsKey(rev.getId())) {
						m.tag++;
						total.tag++;
					}
				}
			} catch (Throwable t) {
				LOGGER.error("Failed to mine log history for metrics", t);
			}
		}
		List<String> keys = new ArrayList<String>(metricMap.keySet());
		Collections.sort(keys);
		List<Metric> metrics = new ArrayList<Metric>();
		for (String key : keys) {
			metrics.add(metricMap.get(key));
		}
		metrics.add(0, total);
		return metrics;
	}

	public static RefModel getTicketsBranch(Repository r) {
		RefModel ticgitBranch = null;
		try {
			// search for ticgit branch in local heads
			for (RefModel ref : getLocalBranches(r, -1)) {
				if (ref.getDisplayName().endsWith("ticgit")) {
					ticgitBranch = ref;
					break;
				}
			}

			// search for ticgit branch in remote heads
			if (ticgitBranch == null) {
				for (RefModel ref : getRemoteBranches(r, -1)) {
					if (ref.getDisplayName().endsWith("ticgit")) {
						ticgitBranch = ref;
						break;
					}
				}
			}
		} catch (Throwable t) {
			LOGGER.error("Failed to find ticgit branch!", t);
		}
		return ticgitBranch;
	}

	public static List<TicketModel> getTickets(Repository r) {
		RefModel ticgitBranch = getTicketsBranch(r);
		List<PathModel> paths = getFilesInPath(r, null, ticgitBranch.getCommit());
		List<TicketModel> tickets = new ArrayList<TicketModel>();
		for (PathModel ticketFolder : paths) {
			if (ticketFolder.isTree()) {
				try {
					TicketModel t = new TicketModel(ticketFolder.name);
					readTicketContents(r, ticgitBranch, t);
					tickets.add(t);
				} catch (Throwable t) {
					LOGGER.error("Failed to get a ticket!", t);
				}
			}
		}
		Collections.sort(tickets);
		Collections.reverse(tickets);
		return tickets;
	}

	public static TicketModel getTicket(Repository r, String ticketFolder) {
		RefModel ticketsBranch = getTicketsBranch(r);
		if (ticketsBranch != null) {
			try {
				TicketModel ticket = new TicketModel(ticketFolder);
				readTicketContents(r, ticketsBranch, ticket);
				return ticket;
			} catch (Throwable t) {
				LOGGER.error("Failed to get ticket " + ticketFolder, t);
			}
		}
		return null;
	}

	private static void readTicketContents(Repository r, RefModel ticketsBranch, TicketModel ticket) {
		List<PathModel> ticketFiles = getFilesInPath(r, ticket.name, ticketsBranch.getCommit());
		for (PathModel file : ticketFiles) {
			String content = getRawContentAsString(r, ticketsBranch.getCommit(), file.path).trim();
			if (file.name.equals("TICKET_ID")) {
				ticket.id = content;
			} else if (file.name.equals("TITLE")) {
				ticket.title = content;
			} else {
				String[] chunks = file.name.split("_");
				if (chunks[0].equals("ASSIGNED")) {
					ticket.handler = content;
				} else if (chunks[0].equals("COMMENT")) {
					try {
						Comment c = new Comment(file.name, content);
						ticket.comments.add(c);
					} catch (ParseException e) {
						e.printStackTrace();
					}
				} else if (chunks[0].equals("TAG")) {
					if (content.startsWith("TAG_")) {
						ticket.tags.add(content.substring(4));
					} else {
						ticket.tags.add(content);
					}
				} else if (chunks[0].equals("STATE")) {
					ticket.state = content;
				}
			}
		}
		Collections.sort(ticket.comments);
	}

	public static String getTicketContent(Repository r, String filePath) {
		RefModel ticketsBranch = getTicketsBranch(r);
		if (ticketsBranch != null) {
			return getRawContentAsString(r, ticketsBranch.getCommit(), filePath);
		}
		return "";
	}
}