#!/usr/bin/env python3

import argparse
from os import path, makedirs, walk, listdir, remove
from shutil import copy, rmtree
from subprocess import run


def folder(default_search, user_input):
    if path.sep in user_input:
        return user_input
    else:
        the_path = path.dirname(path.dirname(path.abspath(__file__)))
        the_path = path.join(the_path, default_search, user_input)
        return the_path


parser = argparse.ArgumentParser(description='''
    Expand a patchset into a git repository (based on git-am)
''')

parser.add_argument('patchset', metavar='PATCHSET', action='store', type=lambda x: folder('patchset', x), help='Patchset (assumed in ../patchset/)')
parser.add_argument('worktree', metavar='WORKTREE', action='store', type=lambda x: folder('worktree', x), help='Destination worktree (assumed in ../worktree/)')
group = parser.add_mutually_exclusive_group()
group.add_argument('--base', metavar='SRC', action='store', default='SuperMarioProj.1994-02-09', type=lambda x: folder('base', x), help='Base source tree (default=SuperMarioProj.1994-02-09, assumed in ../base/)')

args = parser.parse_args()


assert path.exists(args.patchset)
assert not path.exists(path.join(args.patchset, '.git')) # protect against argument swap


horst = ['-c', 'user.name=Horst Beepmanh', '-c', 'user.email=<>']
def git(*gitargs):
    run(['git', *horst, *gitargs], cwd=args.worktree, check=True)


try:
    rmtree(args.worktree)
except FileNotFoundError:
    pass
makedirs(args.worktree)

with open(path.join(args.worktree, '.gitignore'), 'a') as f:
    f.write('.*\n*.dmg\nBuild*/\n')

git('init')
git('add', '-f', '.gitignore')
git('commit', '-m', 'Useful non-source things')

for walk_base, walk_dirs, walk_files in walk(args.base):
    walk_dirs[:] = [x for x in walk_dirs if not x.startswith('.')]
    walk_files[:] = [x for x in walk_files if not x.startswith('.')]

    other_dir = path.join(args.worktree, path.relpath(walk_base, args.base))

    makedirs(other_dir, exist_ok=True)

    for this_file in walk_files:
        copy(path.join(walk_base, this_file), other_dir)

git('add', '.')
git('commit', '-m', path.basename(args.base))
git('tag', 'patchset-base')

patchfiles = [path.join(args.patchset, x) for x in sorted(listdir(args.patchset)) if path.splitext(x)[1].lower() == '.patch']
git('am', *patchfiles)