# Copyright (C) 2009 Jelmer Vernooij <jelmer@samba.org>
#
# 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

"""Map from Git sha's to Bazaar objects."""

from dulwich.objects import (
    Blob,
    Tree,
    )
import stat

from bzrlib import (
    errors,
    ui,
    )

from bzrlib.plugins.git.mapping import (
    inventory_to_tree_and_blobs,
    mapping_registry,
    revision_to_commit,
    )
from bzrlib.plugins.git.shamap import (
    SqliteGitShaMap,
    )


class BazaarObjectStore(object):
    """A Git-style object store backed onto a Bazaar repository."""

    def __init__(self, repository, mapping=None):
        self.repository = repository
        if mapping is None:
            self.mapping = self.repository.get_mapping()
        else:
            self.mapping = mapping
        self._idmap = SqliteGitShaMap(self.repository._transport)

    def _update_sha_map(self):
        all_revids = self.repository.all_revision_ids()
        graph = self.repository.get_graph()
        present_revids = set(self._idmap.revids())
        pb = ui.ui_factory.nested_progress_bar()
        try:
            for i, revid in enumerate(graph.iter_topo_order(all_revids)):
                if revid in present_revids:
                    continue
                pb.update("updating git map", i, len(all_revids))
                self._update_sha_map_revision(revid)
        finally:
            self._idmap.commit()
            pb.finished()

    def _update_sha_map_revision(self, revid):
        inv = self.repository.get_inventory(revid)
        objects = inventory_to_tree_and_blobs(self.repository, self.mapping,
            revid)
        for sha, o, path in objects:
            if path == "":
                tree_sha = sha
            ie = inv[inv.path2id(path)]
            if ie.kind in ("file", "symlink"):
                self._idmap.add_entry(sha, "blob", (ie.file_id, ie.revision))
            elif ie.kind == "directory":
                self._idmap.add_entry(sha, "tree", (path, ie.revision))
            else:
                raise AssertionError()
        rev = self.repository.get_revision(revid)
        commit_obj = revision_to_commit(rev, tree_sha,
            self._idmap._parent_lookup)
        try:
            foreign_revid, mapping = mapping_registry.parse_revision_id(revid)
        except errors.InvalidRevisionId:
            pass
        else:
            if foreign_revid != commit_obj.id:
                raise AssertionError("recreated git commit had different sha1: expected %s, got %s" % (foreign_revid, commit_obj.id))
        self._idmap.add_entry(commit_obj.id, "commit", (revid, tree_sha))

    def _get_blob(self, fileid, revision):
        """Return a Git Blob object from a fileid and revision stored in bzr.
        
        :param fileid: File id of the text
        :param revision: Revision of the text
        """
        text = self.repository.texts.get_record_stream([(fileid, revision)],
            "unordered", True).next().get_bytes_as("fulltext")
        blob = Blob()
        blob._text = text
        return blob

    def _get_tree(self, path, revid, inv=None):
        """Return a Git Tree object from a path and a revision stored in bzr.

        :param path: path in the tree.
        :param revision: Revision of the tree.
        """
        if inv is None:
            inv = self.repository.get_inventory(revid)
        tree = Tree()
        fileid = inv.path2id(path)
        for name, ie in inv[fileid].children.iteritems():
            if ie.kind == "directory":
                subtree = self._get_tree(inv.id2path(ie.file_id), revid, inv)
                tree.add(stat.S_IFDIR, name.encode('UTF-8'), subtree.id)
            elif ie.kind == "file":
                blob = self._get_blob(ie.file_id, ie.revision)
                mode = stat.S_IFREG | 0644
                if ie.executable:
                    mode |= 0111
                tree.add(mode, name.encode('UTF-8'), blob.id)
            elif ie.kind == "symlink":
                raise AssertionError("Symlinks not yet supported")
        tree.serialize()
        return tree

    def _get_commit(self, revid, tree_sha):
        rev = self.repository.get_revision(revid)
        return revision_to_commit(rev, tree_sha, self._idmap._parent_lookup)

    def get_raw(self, sha):
        obj = self[sha]
        assert obj.id == sha
        return obj._text

    def __getitem__(self, sha):
        # See if sha is in map
        try:
            (type, type_data) = self._idmap.lookup_git_sha(sha)
        except KeyError:
            # if not, see if there are any unconverted revisions and add them 
            # to the map, search for sha in map again
            self._update_sha_map()
            (type, type_data) = self._idmap.lookup_git_sha(sha)
        # convert object to git object
        if type == "commit":
            return self._get_commit(*type_data)
        elif type == "blob":
            return self._get_blob(*type_data)
        elif type == "tree":
            return self._get_tree(*type_data)
        else:
            raise AssertionError("Unknown object type '%s'" % type)