#!/usr/bin/env python3
"""Reconstruct the MIT JEI source fork from an immutable upstream commit and patch."""
from pathlib import Path
import hashlib, io, shutil, subprocess, tarfile
ROOT=Path(__file__).resolve().parents[1]
COMMIT='aae2dfcfb82e6b5bce787ba72bb2eda7339b274f'
PATCH=ROOT/'mods/jei/patches/26.3.patch'
DEST=ROOT/'build/jei-fork'
STAMP=COMMIT+':'+hashlib.sha256(PATCH.read_bytes()+Path(__file__).read_bytes()).hexdigest()
if (DEST/'.sanctuary-source').exists() and (DEST/'.sanctuary-source').read_text()==STAMP:
    raise SystemExit(0)
mirror=ROOT/'build/jei-26.2-upstream'
if not (mirror/'.git').exists():
    subprocess.run(['git','clone','--no-checkout','https://github.com/mezz/JustEnoughItems.git',str(mirror)],check=True)
subprocess.run(['git','-C',str(mirror),'cat-file','-e',COMMIT+'^{commit}'],check=True)
archive=subprocess.check_output(['git','-C',str(mirror),'archive',COMMIT])
tmp=ROOT/'build/jei-fork-preparing'
if tmp.exists(): shutil.rmtree(tmp)
tmp.mkdir(parents=True)
with tarfile.open(fileobj=io.BytesIO(archive)) as tar:
    for entry in tar:
        target=(tmp/entry.name).resolve()
        if tmp.resolve() not in target.parents or not (entry.isfile() or entry.isdir()):
            raise RuntimeError('Unexpected upstream archive entry: '+entry.name)
        if entry.isdir(): target.mkdir(parents=True,exist_ok=True)
        else:
            target.parent.mkdir(parents=True,exist_ok=True)
            target.write_bytes(tar.extractfile(entry).read())
subprocess.run(['patch','-E','-p1','--batch','--forward','-i',str(PATCH)],cwd=tmp,check=True,stdout=subprocess.DEVNULL)
(tmp/'.sanctuary-source').write_text(STAMP)
if DEST.exists(): shutil.rmtree(DEST)
tmp.rename(DEST)
print('JEI source verified and patched: '+COMMIT)