# Copyright (C) 2007 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""An adapter between a Git Branch and a Bazaar Branch"""

from bzrlib import (
    branch,
    config,
    revision,
    tag,
    )
from bzrlib.decorators import needs_read_lock
from bzrlib.trace import mutter

from bzrlib.plugins.git.foreign import ForeignBranch
from bzrlib.plugins.git.errors import LightWeightCheckoutsNotSupported

from dulwich.objects import (
        Commit,
        Tag,
        )

class GitTagDict(tag.BasicTags):

    def __init__(self, branch):
        self.branch = branch
        self.repository = branch.repository

    def get_tag_dict(self):
        ret = {}
        for k,v in self.repository._git.tags.iteritems():
            obj = self.repository._git.get_object(v)
            while isinstance(obj, Tag):
                v = obj.object[1]
                obj = self.repository._git.get_object(v)
            if not isinstance(obj, Commit):
                mutter("Tag %s points at object %r that is not a commit, ignoring", k, obj)
                continue
            ret[k] = self.branch.mapping.revision_id_foreign_to_bzr(v)
        return ret

    def set_tag(self, name, revid):
        self.repository._git.tags[name] = revid


class GitBranchConfig(config.BranchConfig):
    """BranchConfig that uses locations.conf in place of branch.conf"""

    def __init__(self, branch):
        config.BranchConfig.__init__(self, branch)
        # do not provide a BranchDataConfig
        self.option_sources = self.option_sources[0], self.option_sources[2]

    def set_user_option(self, name, value, store=config.STORE_BRANCH, warn_masked=False):
        """Force local to True"""
        config.BranchConfig.set_user_option(self, name, value, store=config.STORE_LOCATION, warn_masked=warn_masked)


class GitBranchFormat(branch.BranchFormat):

    def get_format_description(self):
        return 'Git Branch'

    def supports_tags(self):
        return True


class GitBranch(ForeignBranch):
    """An adapter to git repositories for bzr Branch objects."""

    def __init__(self, bzrdir, repository, name, head, lockfiles):
        self.repository = repository
        super(GitBranch, self).__init__(repository.get_mapping())
        self.control_files = lockfiles
        self.bzrdir = bzrdir
        self.name = name
        self.head = head
        self.base = bzrdir.transport.base
        self._format = GitBranchFormat()

    def dpull(self, source, stop_revision=None):
        if stop_revision is None:
            stop_revision = source.last_revision()
        # FIXME: Check for diverged branches
        revidmap = self.repository.dfetch(source.repository, stop_revision)
        self.head, self.mapping = self.mapping.revision_id_bzr_to_foreign(revidmap[stop_revision])
        return revidmap

    def lock_write(self):
        self.control_files.lock_write()

    def get_stacked_on_url(self):
        # Git doesn't do stacking (yet...)
        return None

    def get_parent(self):
        """See Branch.get_parent()."""
        return None

    def set_parent(self, url):
        pass

    def lock_read(self):
        self.control_files.lock_read()

    def unlock(self):
        self.control_files.unlock()

    def get_physical_lock_status(self):
        return False

 
class LocalGitBranch(GitBranch):

    @needs_read_lock
    def last_revision(self):
        # perhaps should escape this ?
        if self.head is None:
            return revision.NULL_REVISION
        return self.mapping.revision_id_foreign_to_bzr(self.head)

    def create_checkout(self, to_location, revision_id=None, 
                        lightweight=False, accelerator_tree=None, hardlink=False):
        if lightweight:
            raise LightWeightCheckoutsNotSupported()
        return self._create_heavyweight_checkout(to_location, revision_id, hardlink)

    def _create_heavyweight_checkout(self, to_location, revision_id=None, 
                                     hardlink=False):
        """Create a new heavyweight checkout of this branch.

        :param to_location: URL of location to create the new checkout in.
        :param revision_id: Revision that should be the tip of the checkout.
        :param hardlink: Whether to hardlink
        :return: WorkingTree object of checkout.
        """
        checkout_branch = BzrDir.create_branch_convenience(
            to_location, force_new_tree=False, format=get_rich_root_format())
        checkout = checkout_branch.bzrdir
        checkout_branch.bind(self)
        # pull up to the specified revision_id to set the initial 
        # branch tip correctly, and seed it with history.
        checkout_branch.pull(self, stop_revision=revision_id)
        return checkout.create_workingtree(revision_id, hardlink=hardlink)

    def _make_tags(self):
        return GitTagDict(self)

    def _gen_revision_history(self):
        if self.head is None:
            return []
        ret = list(self.repository.iter_reverse_revision_history(self.last_revision()))
        ret.reverse()
        return ret

    def get_config(self):
        return GitBranchConfig(self)

    def get_push_location(self):
        """See Branch.get_push_location."""
        push_loc = self.get_config().get_user_option('push_location')
        return push_loc

    def set_push_location(self, location):
        """See Branch.set_push_location."""
        self.get_config().set_user_option('push_location', location,
                                          store=config.STORE_LOCATION)

    def supports_tags(self):
        return True

    def sprout(self, to_bzrdir, revision_id=None):
        """See Branch.sprout()."""
        result = to_bzrdir.create_branch()
        self.copy_content_into(result, revision_id=revision_id)
        result.set_parent(self.bzrdir.root_transport.base)
        return result