#!/usr/bin/env python3

import argparse
from os import path, makedirs, walk, listdir, remove, stat, chmod
from shutil import copy, rmtree
from subprocess import run
from shlex import quote

from folder import folder


def make_executable(path): # thanks to Jonathon Reinhart on SO
    mode = stat(path).st_mode
    mode |= (mode & 0o444) >> 2    # copy R bits to X
    chmod(path, mode)

def relpath(dest, src):
    return path.relpath(path.abspath(dest), path.abspath(src))

def path_to_script(script_name, from_worktree):
    script_path = path.join(path.dirname(__file__), script_name)
    return relpath(script_path, from_worktree)


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')

with open(path.join(args.worktree, '.build'), 'w') as f:
    print('#!/bin/sh', file=f)
    print('exec ' + quote(path_to_script('build', args.worktree)) + ' . "$@"', file=f)
    make_executable(f.name)

with open(path.join(args.worktree, '.flatten'), 'w') as f:
    print('#!/bin/sh', file=f)
    print('exec ' + quote(path_to_script('flatten', args.worktree)) + ' . ' + relpath(args.patchset, args.worktree) + ' "$@"', file=f)
    make_executable(f.name)

git('init')
git('add', '-f', '.gitignore', '.build', '.flatten')
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)