#!/usr/bin/python3
# -*- coding: utf-8 -*-

# Copyright (C) 2018 SUSE LLC
#
# 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.

from git_sort import pygit2_wrapper as pygit2
from git_sort.git_sort import *
import argparse
import pprint
import sys


parser = argparse.ArgumentParser(
    description="Sort input lines according to the upstream order of "
    "commits that each line represents, with the first word on the line "
    "taken to be a commit id.")
parser.add_argument("-d", "--dump-heads", action="store_true",
                    help="Print the branch heads used for sorting "
                    "(debugging).")
args = parser.parse_args()

try:
    path = os.environ["GIT_DIR"]
except KeyError:
    try:
        # depending on the pygit2 version, discover_repository() will either
        # raise KeyError or return None if a repository is not found.
        path = pygit2.discover_repository(os.getcwd())
    except KeyError:
        path = None
if path is None:
    print("Error: Not a git repository", file=sys.stderr)
    sys.exit(1)
repo = pygit2.Repository(path)

if args.dump_heads:
    needs_rebuild = False
    try:
        with Cache() as cache:
            try:
                print("Cached heads (version %d):" % cache["version"])
            except CKeyError:
                print("No usable cache")
                needs_rebuild = True
            else:
                try:
                    history = cache["history"]
                except CUnsupported:
                    print("Unsupported cache version")
                    needs_rebuild = True
                except CInconsistent:
                    print("Inconsistent cache content")
                    needs_rebuild = True
                else:
                    pprint.pprint(list(history.keys()))
    except CAbsent:
        print("No usable cache")
        needs_rebuild = True
    except CNeedsRebuild:
        needs_rebuild = True
    except CError as err:
        print("Error: %s" % (err,), file=sys.stderr)
        sys.exit(1)

    try:
        repo_heads = get_heads(repo)
    except GSError as err:
        print("Error: %s" % (err,), file=sys.stderr)
        sys.exit(1)
    if not needs_rebuild and list(history.keys()) != list(repo_heads.items()):
        needs_rebuild = True
    print("Current heads (version %d):" % Cache.version)
    pprint.pprint(list(repo_heads.items()))
    if needs_rebuild:
        action = "Will"
    else:
        action = "Will not"
    print("%s rebuild history" % (action,))
    sys.exit(0)

index = SortIndex(repo)
dest = {}
oot = []
num = 0
for line in sys.stdin.readlines():
    num = num + 1
    tokens = line.strip().split(None, 1)
    if not tokens:
        continue
    try:
        commit = repo.revparse_single(tokens[0])
    except ValueError:
        print("Error: did not find a commit hash on line %d:\n%s" %
              (num, line.strip(),), file=sys.stderr)
        sys.exit(1)
    except KeyError:
        print("Error: commit hash on line %d not found in the repository:\n%s" %
              (num, line.strip(),), file=sys.stderr)
        sys.exit(1)
    h = str(commit.id)
    if h in dest:
        dest[h][1].append(line)
    else:
        try:
            ic = index.lookup(h)
        except GSKeyError:
            oot.append(line)
        else:
            dest[h] = (ic, [line],)

print("".join([line
               for ic, lines in sorted(dest.values(),
                                       key=operator.itemgetter(0))
                   for line in lines
              ]), end="")

if oot:
    print("Error: the following entries were not found in the indexed heads:",
          file=sys.stderr)
    print("".join(oot), end="")
    sys.exit(1)