# -*- coding: utf-8 -*-
#
# Copyright (C) 2012 Edgewall Software
# Copyright (C) 2006-2011, Herbert Valerio Riedel <hvr@gnu.org>
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://trac.edgewall.org/wiki/TracLicense.
#
# This software consists of voluntary contributions made by many
# individuals. For the exact contribution history, see the revision
# history and logs, available at http://trac.edgewall.org/log/.

from __future__ import with_statement

from datetime import datetime
import itertools
import os
import sys

from genshi.builder import tag
from genshi.core import Markup

from trac.cache import cached
from trac.config import BoolOption, IntOption, PathOption, Option
from trac.core import *
from trac.util import TracError, shorten_line
from trac.util.datefmt import FixedOffset, to_timestamp, format_datetime
from trac.util.text import to_unicode, exception_to_unicode
from trac.util.translation import _
from trac.versioncontrol.api import Changeset, Node, Repository, \
                                    IRepositoryConnector, NoSuchChangeset, \
                                    NoSuchNode, IRepositoryProvider
from trac.versioncontrol.cache import CACHE_YOUNGEST_REV, CachedRepository, \
                                      CachedChangeset
from trac.versioncontrol.web_ui import IPropertyRenderer
from trac.web.chrome import Chrome
from trac.wiki import IWikiSyntaxProvider

from tracopt.versioncontrol.git import PyGIT


class GitCachedRepository(CachedRepository):
    """Git-specific cached repository."""

    def display_rev(self, rev):
        return self.short_rev(rev)

    def short_rev(self, path):
        return self.repos.short_rev(path)

    def normalize_rev(self, rev):
        if not rev:
            return self.get_youngest_rev()
        normrev = self.repos.git.verifyrev(rev)
        if normrev is None:
            raise NoSuchChangeset(rev)
        return normrev

    def get_youngest_rev(self):
        # return None if repository is empty
        return CachedRepository.get_youngest_rev(self) or None

    def child_revs(self, rev):
        return self.repos.child_revs(rev)

    def get_changesets(self, start, stop):
        for key, csets in itertools.groupby(
                CachedRepository.get_changesets(self, start, stop),
                key=lambda cset: cset.date):
            csets = list(csets)
            if len(csets) == 1:
                yield csets[0]
                continue
            rev_csets = dict((cset.rev, cset) for cset in csets)
            while rev_csets:
                revs = [rev for rev in rev_csets
                            if not any(r in rev_csets
                                       for r in self.repos.child_revs(rev))]
                for rev in sorted(revs):
                    yield rev_csets.pop(rev)

    def get_changeset(self, rev):
        return GitCachedChangeset(self, self.normalize_rev(rev), self.env)

    def sync(self, feedback=None, clean=False):
        if clean:
            self.remove_cache()

        metadata = self.metadata
        self.save_metadata(metadata)
        meta_youngest = metadata.get(CACHE_YOUNGEST_REV)
        repos = self.repos

        def is_synced(rev):
            for count, in self.env.db_query("""
                    SELECT COUNT(*) FROM revision WHERE repos=%s AND rev=%s
                    """, (self.id, rev)):
                return count > 0
            return False

        def traverse(rev, seen, revs=None):
            if revs is None:
                revs = []
            while True:
                if rev in seen:
                    return revs
                seen.add(rev)
                if is_synced(rev):
                    return revs
                revs.append(rev)
                parent_revs = repos.parent_revs(rev)
                if not parent_revs:
                    return revs
                if len(parent_revs) == 1:
                    rev = parent_revs[0]
                    continue
                idx = len(revs)
                traverse(parent_revs.pop(), seen, revs)
                for parent in parent_revs:
                    revs[idx:idx] = traverse(parent, seen)

        while True:
            repos.sync()
            repos_youngest = repos.youngest_rev
            updated = False
            seen = set()

            for rev in repos.git.all_revs():
                if repos.child_revs(rev):
                    continue
                revs = traverse(rev, seen)  # topology ordered
                while revs:
                    # sync revision from older revision to newer revision
                    rev = revs.pop()
                    self.log.info("Trying to sync revision [%s]", rev)
                    cset = repos.get_changeset(rev)
                    with self.env.db_transaction as db:
                        try:
                            self._insert_changeset(db, rev, cset)
                            updated = True
                        except self.env.db_exc.IntegrityError, e:
                            self.log.info('Revision %s already cached: %r',
                                          rev, e)
                            db.rollback()
                            continue
                    if feedback:
                        feedback(rev)

            if updated:
                continue  # sync again

            if meta_youngest != repos_youngest:
                with self.env.db_transaction as db:
                    db("""
                        UPDATE repository SET value=%s WHERE id=%s AND name=%s
                        """, (repos_youngest, self.id, CACHE_YOUNGEST_REV))
                    del self.metadata
            return


class GitCachedChangeset(CachedChangeset):
    """Git-specific cached changeset.

    Handles get_branches()
    """
    def get_branches(self):
        _rev = self.rev

        return [(k, v == _rev) for k, v in
                 self.repos.repos.git.get_branch_contains(_rev, resolve=True)]


def _last_iterable(iterable):
    """helper for detecting last iteration in for-loop"""
    i = iter(iterable)
    v = i.next()
    for nextv in i:
        yield False, v
        v = nextv
    yield True, v

def intersperse(sep, iterable):
    """The 'intersperse' generator takes an element and an iterable and
    intersperses that element between the elements of the iterable.

    inspired by Haskell's ``Data.List.intersperse``
    """

    for i, item in enumerate(iterable):
        if i: yield sep
        yield item

# helper
def _parse_user_time(s):
    """Parse author or committer attribute lines and return
    corresponding ``(user, timestamp)`` pair.
    """

    user, time, tz_str = s.rsplit(None, 2)
    tz = FixedOffset((int(tz_str) * 6) / 10, tz_str)
    time = datetime.fromtimestamp(float(time), tz)
    return user, time


class GitConnector(Component):

    implements(IRepositoryConnector, IWikiSyntaxProvider)

    def __init__(self):
        self._version = None

        try:
            self._version = PyGIT.Storage.git_version(git_bin=self.git_bin)
        except PyGIT.GitError, e:
            self.log.error("GitError: " + str(e))

        if self._version:
            self.log.info("detected GIT version %s" % self._version['v_str'])
            self.env.systeminfo.append(('GIT', self._version['v_str']))
            if not self._version['v_compatible']:
                self.log.error("GIT version %s installed not compatible"
                               "(need >= %s)" %
                               (self._version['v_str'],
                                self._version['v_min_str']))

    # IWikiSyntaxProvider methods

    def _format_sha_link(self, formatter, sha, label):
        # FIXME: this function needs serious rethinking...

        reponame = ''

        context = formatter.context
        while context:
            if context.resource.realm in ('source', 'changeset'):
                reponame = context.resource.parent.id
                break
            context = context.parent

        try:
            repos = self.env.get_repository(reponame)

            if not repos:
                raise Exception("Repository '%s' not found" % reponame)

            sha = repos.normalize_rev(sha) # in case it was abbreviated
            changeset = repos.get_changeset(sha)
            return tag.a(label, class_='changeset',
                         title=shorten_line(changeset.message),
                         href=formatter.href.changeset(sha, repos.reponame))
        except Exception, e:
            return tag.a(label, class_='missing changeset',
                         title=to_unicode(e), rel='nofollow')

    def get_wiki_syntax(self):
        yield (r'(?:\b|!)r?[0-9a-fA-F]{%d,40}\b' % self.wiki_shortrev_len,
               lambda fmt, sha, match:
                    self._format_sha_link(fmt, sha.startswith('r')
                                          and sha[1:] or sha, sha))

    def get_link_resolvers(self):
        yield ('sha', lambda fmt, _, sha, label, match=None:
                        self._format_sha_link(fmt, sha, label))

    # IRepositoryConnector methods

    persistent_cache = BoolOption('git', 'persistent_cache', 'false',
        """Enable persistent caching of commit tree.""")

    cached_repository = BoolOption('git', 'cached_repository', 'false',
        """Wrap `GitRepository` in `CachedRepository`.""")

    shortrev_len = IntOption('git', 'shortrev_len', 7,
        """The length at which a sha1 should be abbreviated to (must
        be >= 4 and <= 40).
        """)

    wiki_shortrev_len = IntOption('git', 'wikishortrev_len', 40,
        """The minimum length of an hex-string for which
        auto-detection as sha1 is performed (must be >= 4 and <= 40).
        """)

    trac_user_rlookup = BoolOption('git', 'trac_user_rlookup', 'false',
        """Enable reverse mapping of git email addresses to trac user ids
        (costly if you have many users).""")

    use_committer_id = BoolOption('git', 'use_committer_id', 'true',
        """Use git-committer id instead of git-author id for the
        changeset ''Author'' field.
        """)

    use_committer_time = BoolOption('git', 'use_committer_time', 'true',
        """Use git-committer timestamp instead of git-author timestamp
        for the changeset ''Timestamp'' field.
        """)

    git_fs_encoding = Option('git', 'git_fs_encoding', 'utf-8',
        """Define charset encoding of paths within git repositories.""")

    git_bin = Option('git', 'git_bin', 'git',
        """Path to the git executable.""")


    def get_supported_types(self):
        yield ('git', 8)

    def get_repository(self, type, dir, params):
        """GitRepository factory method"""
        assert type == 'git'

        if not (4 <= self.shortrev_len <= 40):
            raise TracError("[git] shortrev_len setting must be within [4..40]")

        if not (4 <= self.wiki_shortrev_len <= 40):
            raise TracError("[git] wikishortrev_len must be within [4..40]")

        if not self._version:
            raise TracError("GIT backend not available")
        elif not self._version['v_compatible']:
            raise TracError("GIT version %s installed not compatible"
                            "(need >= %s)" %
                            (self._version['v_str'],
                             self._version['v_min_str']))

        if self.trac_user_rlookup:
            def rlookup_uid(email):
                """Reverse map 'real name <user@domain.tld>' addresses to trac
                user ids.

                :return: `None` if lookup failed
                """

                try:
                    _, email = email.rsplit('<', 1)
                    email, _ = email.split('>', 1)
                    email = email.lower()
                except Exception:
                    return None

                for _uid, _name, _email in self.env.get_known_users():
                    try:
                        if email == _email.lower():
                            return _uid
                    except Exception:
                        continue

        else:
            def rlookup_uid(_):
                return None

        repos = GitRepository(self.env, dir, params, self.log,
                              persistent_cache=self.persistent_cache,
                              git_bin=self.git_bin,
                              git_fs_encoding=self.git_fs_encoding,
                              shortrev_len=self.shortrev_len,
                              rlookup_uid=rlookup_uid,
                              use_committer_id=self.use_committer_id,
                              use_committer_time=self.use_committer_time,
                              )

        if self.cached_repository:
            repos = GitCachedRepository(self.env, repos, self.log)
            self.log.debug("enabled CachedRepository for '%s'" % dir)
        else:
            self.log.debug("disabled CachedRepository for '%s'" % dir)

        return repos


class CsetPropertyRenderer(Component):

    implements(IPropertyRenderer)

    # relied upon by GitChangeset
    def match_property(self, name, mode):
        # default renderer has priority 1
        return (name in ('Parents',
                         'Children',
                         'Branches',
                         'git-committer',
                         'git-author',
                         ) and mode == 'revprop') and 4 or 0

    def render_property(self, name, mode, context, props):

        def sha_link(sha, label=None):
            # sha is assumed to be a non-abbreviated 40-chars sha id
            try:
                reponame = context.resource.parent.id
                repos = self.env.get_repository(reponame)
                cset = repos.get_changeset(sha)
                if label is None:
                    label = repos.display_rev(sha)

                return tag.a(label, class_='changeset',
                             title=shorten_line(cset.message),
                             href=context.href.changeset(sha, repos.reponame))

            except Exception, e:
                return tag.a(sha, class_='missing changeset',
                             title=to_unicode(e), rel='nofollow')

        if name == 'Branches':
            branches = props[name]

            # simple non-merge commit
            return tag(*intersperse(', ', (sha_link(rev, label)
                                           for label, rev in branches)))

        elif name in ('Parents', 'Children'):
            revs = props[name] # list of commit ids

            if name == 'Parents' and len(revs) > 1:
                # we got a merge...
                current_sha = context.resource.id
                reponame = context.resource.parent.id

                parent_links = intersperse(', ', \
                    ((sha_link(rev),
                      ' (',
                      tag.a(_("diff"),
                            title=_("Diff against this parent (show the "
                                    "changes merged from the other parents)"),
                            href=context.href.changeset(current_sha, reponame,
                                                        old=rev)),
                      ')')
                     for rev in revs))

                return tag(list(parent_links),
                           tag.br(),
                           tag.span(Markup(_("Note: this is a <strong>merge"
                                             "</strong> changeset, the "
                                             "changes displayed below "
                                             "correspond to the merge "
                                             "itself.")),
                                    class_='hint'),
                           tag.br(),
                           tag.span(Markup(_("Use the <tt>(diff)</tt> links "
                                             "above to see all the changes "
                                             "relative to each parent.")),
                                    class_='hint'))

            # simple non-merge commit
            return tag(*intersperse(', ', map(sha_link, revs)))

        elif name in ('git-committer', 'git-author'):
            user_, time_ = props[name]
            _str = "%s (%s)" % (
                Chrome(self.env).format_author(context.req, user_),
                format_datetime(time_, tzinfo=context.req.tz))
            return unicode(_str)

        raise TracError("Internal error")


class GitRepository(Repository):
    """Git repository"""

    def __init__(self, env, path, params, log,
                 persistent_cache=False,
                 git_bin='git',
                 git_fs_encoding='utf-8',
                 shortrev_len=7,
                 rlookup_uid=lambda _: None,
                 use_committer_id=False,
                 use_committer_time=False,
                 ):

        self.env = env
        self.logger = log
        self.gitrepo = path
        self.params = params
        self.persistent_cache = persistent_cache
        self.shortrev_len = max(4, min(shortrev_len, 40))
        self.rlookup_uid = rlookup_uid
        self.use_committer_time = use_committer_time
        self.use_committer_id = use_committer_id

        try:
            factory = PyGIT.StorageFactory(path, log, not persistent_cache,
                                           git_bin=git_bin,
                                           git_fs_encoding=git_fs_encoding)
            self._git = factory.getInstance()
        except PyGIT.GitError, e:
            log.error(exception_to_unicode(e))
            raise TracError("%s does not appear to be a Git "
                            "repository." % path)

        Repository.__init__(self, 'git:' + path, self.params, log)
        self._cached_git_id = str(self.id)

    def close(self):
        self._git = None

    @property
    def git(self):
        if self.persistent_cache:
            return self._cached_git
        else:
            return self._git

    @cached('_cached_git_id')
    def _cached_git(self):
        self._git.invalidate_rev_cache()
        return self._git

    def get_youngest_rev(self):
        return self.git.youngest_rev()

    def get_oldest_rev(self):
        return self.git.oldest_rev()

    def normalize_path(self, path):
        return path and path.strip('/') or '/'

    def normalize_rev(self, rev):
        if not rev:
            return self.get_youngest_rev()
        normrev = self.git.verifyrev(rev)
        if normrev is None:
            raise NoSuchChangeset(rev)
        return normrev

    def display_rev(self, rev):
        return self.short_rev(rev)

    def short_rev(self, rev):
        return self.git.shortrev(self.normalize_rev(rev),
                                 min_len=self.shortrev_len)

    def get_node(self, path, rev=None, historian=None):
        return GitNode(self, path, rev, self.log, None, historian)

    def get_quickjump_entries(self, rev):
        for bname, bsha in self.git.get_branches():
            yield 'branches', bname, '/', bsha
        for t in self.git.get_tags():
            yield 'tags', t, '/', t

    def get_path_url(self, path, rev):
        return self.params.get('url')

    def get_changesets(self, start, stop):
        for rev in self.git.history_timerange(to_timestamp(start),
                                              to_timestamp(stop)):
            yield self.get_changeset(rev)

    def get_changeset(self, rev):
        """GitChangeset factory method"""
        return GitChangeset(self, rev)

    def get_changeset_uid(self, rev):
        return self.normalize_rev(rev)

    def get_changes(self, old_path, old_rev, new_path, new_rev,
                    ignore_ancestry=0):
        # TODO: handle renames/copies, ignore_ancestry
        if old_path != new_path:
            raise TracError("not supported in git_fs")

        with self.git.get_historian(old_rev,
                                    old_path.strip('/')) as old_historian:
            with self.git.get_historian(new_rev,
                                        new_path.strip('/')) as new_historian:
                for chg in self.git.diff_tree(old_rev, new_rev,
                                              self.normalize_path(new_path)):
                    mode1, mode2, obj1, obj2, action, path, path2 = chg

                    kind = Node.FILE
                    if mode2.startswith('04') or mode1.startswith('04'):
                        kind = Node.DIRECTORY

                    change = GitChangeset.action_map[action]

                    old_node = None
                    new_node = None

                    if change != Changeset.ADD:
                        old_node = self.get_node(path, old_rev, old_historian)
                    if change != Changeset.DELETE:
                        new_node = self.get_node(path, new_rev, new_historian)

                    yield old_node, new_node, kind, change

    def next_rev(self, rev, path=''):
        return self.git.hist_next_revision(rev)

    def previous_rev(self, rev, path=''):
        return self.git.hist_prev_revision(rev)

    def parent_revs(self, rev):
        return self.git.parents(rev)

    def child_revs(self, rev):
        return self.git.children(rev)

    def rev_older_than(self, rev1, rev2):
        return self.git.rev_is_anchestor_of(self.normalize_rev(rev1),
                                            self.normalize_rev(rev2))

    # def clear(self, youngest_rev=None):
    #     self.youngest = None
    #     if youngest_rev is not None:
    #         self.youngest = self.normalize_rev(youngest_rev)
    #     self.oldest = None

    def clear(self, youngest_rev=None):
        self.sync()

    def sync(self, rev_callback=None, clean=None):
        if rev_callback:
            revs = set(self.git.all_revs())

        if self.persistent_cache:
            del self._cached_git  # invalidate persistent cache
        if not self.git.sync():
            return None # nothing expected to change

        if rev_callback:
            revs = set(self.git.all_revs()) - revs
            for rev in revs:
                rev_callback(rev)


class GitNode(Node):

    def __init__(self, repos, path, rev, log, ls_tree_info=None,
                 historian=None):
        self.log = log
        self.repos = repos
        self.fs_sha = None # points to either tree or blobs
        self.fs_perm = None
        self.fs_size = None
        if rev:
            rev = repos.normalize_rev(to_unicode(rev))
        else:
            rev = repos.youngest_rev

        kind = Node.DIRECTORY
        p = path.strip('/')
        if p:  # ie. not the root-tree
            if not rev:
                raise NoSuchNode(path, rev)
            if not ls_tree_info:
                ls_tree_info = repos.git.ls_tree(rev, p) or None
                if ls_tree_info:
                    [ls_tree_info] = ls_tree_info

            if not ls_tree_info:
                raise NoSuchNode(path, rev)

            self.fs_perm, k, self.fs_sha, self.fs_size, _ = ls_tree_info

            # fix-up to the last commit-rev that touched this node
            rev = repos.git.last_change(rev, p, historian)

            if k == 'tree':
                pass
            elif k == 'commit':
                # FIXME: this is a workaround for missing git submodule
                #        support in the plugin
                pass
            elif k == 'blob':
                kind = Node.FILE
            else:
                raise TracError("Internal error (got unexpected object " \
                                "kind '%s')" % k)

        self.created_path = path
        self.created_rev = rev

        Node.__init__(self, repos, path, rev, kind)

    def __git_path(self):
        """return path as expected by PyGIT"""
        p = self.path.strip('/')
        if self.isfile:
            assert p
            return p
        if self.isdir:
            return p and (p + '/')

        raise TracError("internal error")

    def get_content(self):
        if not self.isfile:
            return None

        return self.repos.git.get_file(self.fs_sha)

    def get_properties(self):
        return self.fs_perm and {'mode': self.fs_perm } or {}

    def get_annotations(self):
        if not self.isfile:
            return

        return [rev for rev, lineno in \
                self.repos.git.blame(self.rev,self.__git_path())]

    def get_entries(self):
        if not self.rev:  # if empty repository
            return
        if not self.isdir:
            return

        with self.repos.git.get_historian(self.rev,
                                          self.path.strip('/')) as historian:
            for ent in self.repos.git.ls_tree(self.rev, self.__git_path()):
                yield GitNode(self.repos, ent[-1], self.rev, self.log, ent,
                              historian)

    def get_content_type(self):
        if self.isdir:
            return None

        return ''

    def get_content_length(self):
        if not self.isfile:
            return None

        if self.fs_size is None:
            self.fs_size = self.repos.git.get_obj_size(self.fs_sha)

        return self.fs_size

    def get_history(self, limit=None):
        if not self.rev:  # if empty repository
            return
        # TODO: find a way to follow renames/copies
        for is_last, rev in _last_iterable(self.repos.git.history(self.rev,
                                                self.__git_path(), limit)):
            yield (self.path, rev, Changeset.EDIT if not is_last else
                                   Changeset.ADD)

    def get_last_modified(self):
        if not self.isfile:
            return None

        try:
            msg, props = self.repos.git.read_commit(self.rev)
            user, ts = _parse_user_time(props['committer'][0])
        except:
            self.log.error("internal error (could not get timestamp from "
                           "commit '%s')" % self.rev)
            return None

        return ts


class GitChangeset(Changeset):
    """A Git changeset in the Git repository.

    Corresponds to a Git commit blob.
    """

    action_map = { # see also git-diff-tree(1) --diff-filter
        'A': Changeset.ADD,
        'M': Changeset.EDIT, # modified
        'T': Changeset.EDIT, # file type (mode) change
        'D': Changeset.DELETE,
        'R': Changeset.MOVE, # renamed
        'C': Changeset.COPY
        } # TODO: U, X, B

    def __init__(self, repos, sha):
        if sha is None:
            raise NoSuchChangeset(sha)

        try:
            msg, props = repos.git.read_commit(sha)
        except PyGIT.GitErrorSha:
            raise NoSuchChangeset(sha)

        self.props = props

        assert 'children' not in props
        _children = list(repos.git.children(sha))
        if _children:
            props['children'] = _children

        committer, author = self._get_committer_and_author()
        # use 1st author/committer as changeset owner/timestamp
        c_user = a_user = c_time = a_time = None
        if committer:
            c_user, c_time = _parse_user_time(committer)
        if author:
            a_user, a_time = _parse_user_time(author)

        if repos.use_committer_time:
            time = c_time or a_time
        else:
            time = a_time or c_time

        if repos.use_committer_id:
            user = c_user or a_user
        else:
            user = a_user or c_user

        # try to resolve email address to trac uid
        user = repos.rlookup_uid(user) or user

        Changeset.__init__(self, repos, rev=sha, message=msg, author=user,
                           date=time)

    def _get_committer_and_author(self):
        committer = author = None
        if 'committer' in self.props:
            committer = self.props['committer'][0]
        if 'author' in self.props:
            author = self.props['author'][0]
        return committer, author

    def get_properties(self):
        properties = {}

        if 'parent' in self.props:
            properties['Parents'] = self.props['parent']

        if 'children' in self.props:
            properties['Children'] = self.props['children']

        committer, author = self._get_committer_and_author()
        if author != committer:
            properties['git-committer'] = _parse_user_time(committer)
            properties['git-author'] = _parse_user_time(author)

        branches = list(self.repos.git.get_branch_contains(self.rev,
                                                           resolve=True))
        if branches:
            properties['Branches'] = branches

        return properties

    def get_changes(self):
        paths_seen = set()
        for parent in self.props.get('parent', [None]):
            for mode1, mode2, obj1, obj2, action, path1, path2 in \
                    self.repos.git.diff_tree(parent, self.rev,
                                             find_renames=True):
                path = path2 or path1
                p_path, p_rev = path1, parent

                kind = Node.FILE
                if mode2.startswith('04') or mode1.startswith('04'):
                    kind = Node.DIRECTORY

                action = GitChangeset.action_map[action[0]]

                if action == Changeset.ADD:
                    p_path = ''
                    p_rev = None

                # CachedRepository expects unique (rev, path, change_type) key
                # this is only an issue in case of merges where files required
                # editing
                if path in paths_seen:
                    continue

                paths_seen.add(path)

                yield path, kind, action, p_path, p_rev


    def get_branches(self):
        _rev = self.rev

        return [(k, v == _rev)
                for k, v in self.repos.git.get_branch_contains(_rev,
                                                               resolve=True)]


class GitwebProjectsRepositoryProvider(Component):

    implements(IRepositoryProvider)

    projects_list = PathOption('git', 'projects_list', doc=
        """Path to a gitweb-formatted projects.list""")

    projects_base = PathOption('git', 'projects_base', doc=
        """Path to the base of your git projects""")

    projects_url = Option('git', 'projects_url', doc=
        """Template for project URLs. %s will be replaced with the repo
        name""")

    def get_repositories(self):
        if not self.projects_list:
            return

        for line in open(self.projects_list):
            line = line.strip()
            name = line
            if name.endswith('.git'):
                name = name[:-4]
            repo = {
                'dir': os.path.join(self.projects_base, line),
                'type': 'git',
            }
            description_path = os.path.join(repo['dir'], 'description')
            if os.path.exists(description_path):
                repo['description'] = open(description_path).read().strip()
            if self.projects_url:
                repo['url'] = self.projects_url % name
            yield name, repo