#!/usr/bin/env python3
#
# This file is part of GCC.
#
# GCC 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 3, or (at your option) any later
# version.
#
# GCC 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 GCC; see the file COPYING3.  If not see
# <http://www.gnu.org/licenses/>.  */

from datetime import datetime

try:
    from git import Repo
except ImportError:
    print('Cannot import GitPython package, please install the package:')
    print('  Fedora, openSUSE: python3-GitPython')
    print('  Debian, Ubuntu: python3-git')
    exit(1)

from git_commit import GitCommit, GitInfo, decode_path


def parse_git_revisions(repo_path, revisions, ref_name=None):
    repo = Repo(repo_path)

    def commit_to_info(commit):
        try:
            c = repo.commit(commit)
            diff = repo.commit(commit + '~').diff(commit)

            modified_files = []
            for file in diff:
                if hasattr(file, 'renamed_file'):
                    is_renamed = file.renamed_file
                else:
                    is_renamed = file.renamed
                if file.new_file:
                    t = 'A'
                elif file.deleted_file:
                    t = 'D'
                elif is_renamed:
                    # Consider that renamed files are two operations:
                    # the deletion of the original name
                    # and the addition of the new one.
                    modified_files.append((decode_path(file.a_path), 'D'))
                    t = 'A'
                else:
                    t = 'M'
                modified_files.append((decode_path(file.b_path), t))

            date = datetime.utcfromtimestamp(c.committed_date)
            author = '%s  <%s>' % (c.author.name, c.author.email)
            git_info = GitInfo(c.hexsha, date, author,
                               c.message.split('\n'), modified_files)
            return git_info
        except ValueError:
            return None

    parsed_commits = []
    if '..' in revisions:
        commits = list(repo.iter_commits(revisions))
    else:
        commits = [repo.commit(revisions)]

    for commit in commits:
        git_commit = GitCommit(commit_to_info(commit.hexsha),
                               commit_to_info_hook=commit_to_info,
                               ref_name=ref_name)
        parsed_commits.append(git_commit)
    return parsed_commits