from datetime import datetime
import os
import shutil
import git
import argparse
import core.file_utils as file_utils
from git.repo import Repo
from core.argparse_utils import add_toggle_opt
from core.file_utils import SparkPaths


def _exit(code=0, msg=None):
    if msg is not None:
        print(msg)
    exit(code)


def _get_arg_parser():
    parser = argparse.ArgumentParser(description='Save git-changed files')

    parser.add_argument(
        '--o',
        '--output-dir',
        metavar='path',
        type=str,
        nargs=1,
        help='The directory in which to save files')

    add_toggle_opt(parser, 'modified', help='Backup modified files')
    add_toggle_opt(parser, 'untracked', help='Backup untracked files')

    parser.add_argument(
        '-p',
        '--path',
        metavar='targets',
        type=str,
        action='append',
        nargs='+',
        help='The path(s) whose changes to save')

    parser.set_defaults(modified=True, untracked=False)
    return parser


def _main():
    parser = _get_arg_parser()
    args = parser.parse_args()
    repo = Repo(SparkPaths.root())
    change_types = []
    if args.modified:
        change_types.append('M')
    if args.untracked:
        change_types.append('U')

    if len(change_types) == 0:
        _exit(1, 'No change types specified (no files would be saved)')
    paths = args.path or [['src'], ['tools']]
    # flatten paths
    print(args.path)
    print(repo.working_dir[-24:])
    paths = [
        os.path.realpath(path)[len(repo.working_dir) + 1:]
        for path_arg in paths for path in path_arg
    ]
    print(f'Evaluating: {", ".join(paths)}')
    diff_items = repo.index.diff(None, paths=paths)
    files_to_copy = []
    for di in diff_items:
        if type(di) is not git.Diff:
            continue
        if di.change_type not in change_types:
            continue
        files_to_copy.append(di.a_path)

    if 'U' in change_types:
        for u in repo.untracked_files:
            if any([os.path.commonpath([u, p]) == p for p in paths]):
                files_to_copy.append(u)

    dest = os.path.join(
        SparkPaths.root(), '.tmp', file_utils.fmt_datetime_suffix())
    dest = os.path.realpath(dest)
    dest = file_utils.get_unique_path(dest)
    file_utils.create_dir(dest)
    print(f'Copying files to {dest}')
    for f in files_to_copy:
        f = os.path.normpath(f)
        f = os.path.join(os.path.normpath(repo.working_dir), f)
        dname = os.path.dirname(f)[len(repo.working_dir) + 1:]
        fdest = os.path.join(dest, dname)
        file_utils.create_dir(fdest)
        print(f'copy {f} ({dname})-> {fdest}')
        shutil.copy(f, fdest)


if __name__ == '__main__':
    _main()