# Copyright (C) 2018 Jelmer Vernooij <jelmer@jelmer.uk>
#
# 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Annotate."""

from __future__ import absolute_import

from dulwich.object_store import (
    tree_lookup_path,
    )

from ..errors import (
    NoSuchRevision,
    UnavailableRepresentation,
    )
from ..graph import Graph
from ..revision import (
    NULL_REVISION,
    )


class GitFulltextContentFactory(object):
    """Static data content factory.

    This takes a fulltext when created and just returns that during
    get_bytes_as('fulltext').

    :ivar sha1: None, or the sha1 of the content fulltext.
    :ivar storage_kind: The native storage kind of this factory. Always
        'fulltext'.
    :ivar key: The key of this content. Each key is a tuple with a single
        string in it.
    :ivar parents: A tuple of parent keys for self.key. If the object has
        no parent information, None (as opposed to () for an empty list of
        parents).
     """

    def __init__(self, store, path, revision, blob_id):
        """Create a ContentFactory."""
        self.store = store
        self.key = (path, revision)
        self.storage_kind = 'fulltext'
        self.parents = None
        self.blob_id = blob_id

    def get_bytes_as(self, storage_kind):
        if storage_kind == 'fulltext':
            return self.store[self.blob_id].as_raw_string()
        elif storage_kind == 'chunked':
            return self.store[self.blob_id].as_raw_chunks()
        raise UnavailableRepresentation(self.key, storage_kind,
                                        'fulltext')


class GitAbsentContentFactory(object):
    """Absent data content factory.

    :ivar sha1: None, or the sha1 of the content fulltext.
    :ivar storage_kind: The native storage kind of this factory. Always
        'fulltext'.
    :ivar key: The key of this content. Each key is a tuple with a single
        string in it.
    :ivar parents: A tuple of parent keys for self.key. If the object has
        no parent information, None (as opposed to () for an empty list of
        parents).
     """

    def __init__(self, store, path, revision):
        """Create a ContentFactory."""
        self.store = store
        self.key = (path, revision)
        self.storage_kind = 'absent'
        self.parents = None

    def get_bytes_as(self, storage_kind):
        raise ValueError


class AnnotateProvider(object):

    def __init__(self, change_scanner):
        self.change_scanner = change_scanner
        self.store = self.change_scanner.repository._git.object_store

    def _get_parents(self, path, text_revision):
        commit_id, mapping = (
            self.change_scanner.repository.lookup_bzr_revision_id(
                text_revision))
        text_parents = []
        path = path.encode('utf-8')
        for commit_parent in self.store[commit_id].parents:
            try:
                (path, text_parent) = (
                    self.change_scanner.find_last_change_revision(
                        path, commit_parent))
            except KeyError:
                continue
            if text_parent not in text_parents:
                text_parents.append(text_parent)
        return tuple([
            (path.decode('utf-8'),
                self.change_scanner.repository.lookup_foreign_revision_id(p))
            for p in text_parents])

    def get_parent_map(self, keys):
        ret = {}
        for key in keys:
            (path, text_revision) = key
            if text_revision == NULL_REVISION:
                ret[key] = ()
                continue
            try:
                ret[key] = self._get_parents(path, text_revision)
            except KeyError:
                pass
        return ret

    def get_record_stream(self, keys, ordering, include_delta_closure):
        if ordering == 'topological':
            graph = Graph(self)
            keys = graph.iter_topo_order(keys)
        store = self.change_scanner.repository._git.object_store
        for (path, text_revision) in keys:
            try:
                commit_id, mapping = (
                    self.change_scanner.repository.lookup_bzr_revision_id(
                        text_revision))
            except NoSuchRevision:
                yield GitAbsentContentFactory(store, path, text_revision)
                continue

            try:
                tree_id = store[commit_id].tree
            except KeyError:
                yield GitAbsentContentFactory(store, path, text_revision)
                continue
            try:
                (mode, blob_sha) = tree_lookup_path(
                    store.__getitem__, tree_id, path.encode('utf-8'))
            except KeyError:
                yield GitAbsentContentFactory(store, path, text_revision)
            else:
                yield GitFulltextContentFactory(
                    store, path, text_revision, blob_sha)
