# Copyright (C) 2007-2008 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

"""Converters, etc for going between Bazaar and Git ids."""

from bzrlib import errors, foreign
from bzrlib.inventory import ROOT_ID
from bzrlib.foreign import (
        ForeignVcs, 
        VcsMappingRegistry, 
        ForeignRevision,
        )

def escape_file_id(file_id):
    return file_id.replace('_', '__').replace(' ', '_s')


def unescape_file_id(file_id):
    return file_id.replace("_s", " ").replace("__", "_")


class BzrGitMapping(foreign.VcsMapping):
    """Class that maps between Git and Bazaar semantics."""
    experimental = False

    def __init__(self):
        super(BzrGitMapping, self).__init__(foreign_git)

    def __eq__(self, other):
        return type(self) == type(other) and self.revid_prefix == other.revid_prefix

    @classmethod
    def revision_id_foreign_to_bzr(cls, git_rev_id):
        """Convert a git revision id handle to a Bazaar revision id."""
        return "%s:%s" % (cls.revid_prefix, git_rev_id)

    @classmethod
    def revision_id_bzr_to_foreign(cls, bzr_rev_id):
        """Convert a Bazaar revision id to a git revision id handle."""
        if not bzr_rev_id.startswith("%s:" % cls.revid_prefix):
            raise errors.InvalidRevisionId(bzr_rev_id, cls)
        return bzr_rev_id[len(cls.revid_prefix)+1:], cls()

    def generate_file_id(self, path):
        if path == "":
            return ROOT_ID
        return escape_file_id(path.encode('utf-8'))

    def import_commit(self, commit):
        """Convert a git commit to a bzr revision.

        :return: a `bzrlib.revision.Revision` object.
        """
        if commit is None:
            raise AssertionError("Commit object can't be None")
        rev = ForeignRevision(commit.id, self, self.revision_id_foreign_to_bzr(commit.id))
        rev.parent_ids = tuple([self.revision_id_foreign_to_bzr(p) for p in commit.parents])
        rev.message = commit.message.decode("utf-8", "replace")
        rev.committer = str(commit.committer).decode("utf-8", "replace")
        if commit.committer != commit.author:
            rev.properties['author'] = str(commit.author).decode("utf-8", "replace")
        rev.timestamp = commit.commit_time
        rev.timezone = 0
        return rev

    def export_commit(self, rev, tree_sha):
        """Turn a Bazaar revision in to a Git commit

        :param tree_sha: HACK parameter (until we can retrieve this from the mapping)
        :return dulwich.objects.Commit represent the revision:
        """
        from dulwich.objects import Commit
        commit = Commit()
        commit._tree = tree_sha
        for p in rev.parent_ids:
            commit._parents.append(self.revision_id_bzr_to_foreign(p))
        commit._message = rev.message
        commit._committer = rev.committer
        if 'author' in rev.properties:
            commit._author = rev.properties['author']
        else:
            commit._author = rev.committer
        commit._commit_time = long(rev.timestamp)
        commit.serialize()
        return commit


class BzrGitMappingv1(BzrGitMapping):
    revid_prefix = 'git-v1'
    experimental = False


class BzrGitMappingExperimental(BzrGitMappingv1):
    revid_prefix = 'git-experimental'
    experimental = True


class GitMappingRegistry(VcsMappingRegistry):

    def revision_id_bzr_to_foreign(self, bzr_revid):
        if not bzr_revid.startswith("git-"):
            raise errors.InvalidRevisionId(bzr_revid, None)
        (mapping_version, git_sha) = bzr_revid.split(":", 1)
        mapping = self.get(mapping_version)
        return mapping.revision_id_bzr_to_foreign(bzr_revid)

    parse_revision_id = revision_id_bzr_to_foreign


mapping_registry = GitMappingRegistry()
mapping_registry.register_lazy('git-v1', "bzrlib.plugins.git.mapping",
                                   "BzrGitMappingv1")
mapping_registry.register_lazy('git-experimental', "bzrlib.plugins.git.mapping",
                                   "BzrGitMappingExperimental")


class ForeignGit(ForeignVcs):
    """Foreign Git."""

    def __init__(self):
        super(ForeignGit, self).__init__(mapping_registry)

    @classmethod
    def show_foreign_revid(cls, foreign_revid):
        return { "git commit": foreign_revid }


foreign_git = ForeignGit()
default_mapping = BzrGitMappingv1()