import hashlib
import json
from pathlib import Path

MODEL=Path(__file__).resolve().parent
CFG=json.loads((MODEL/'config.json').read_text(encoding='utf-8'))
ROOT=Path(CFG['root']);EXP=ROOT/CFG['experiment'];AC=ROOT/CFG['prior_experiment']

def digest(path):
    h=hashlib.sha256()
    with Path(path).open('rb') as f:
        for b in iter(lambda:f.read(8<<20),b''):h.update(b)
    return h.hexdigest()

def save(path,value):
    path=Path(path);path.parent.mkdir(parents=True,exist_ok=True)
    with path.open('x',encoding='utf-8') as f:json.dump(value,f,indent=2,ensure_ascii=False,allow_nan=False);f.write('\n')

def source_hashes():
    return {p.name:digest(p) for p in sorted(MODEL.iterdir()) if p.is_file() and p.name not in ('manifest.json','checksums.sha256')}

def check_prereg():
    pre=json.loads((EXP/'protocol/preregistered.json').read_text())
    assert pre['source_hashes']==source_hashes(),'Source changed after preregistration'
    for r in pre['input_hashes']:
        assert digest(ROOT/r['path'])==r['sha256'],r['path']
    return pre