from pathlib import Path
from fractions import Fraction as F
import json, hashlib, datetime
ROOT=Path(__file__).resolve().parent.parent
E,P,J=F(25,23),F(70,69),F(300,299)
def inv(n):
    if not isinstance(n,int) or n<0: raise ValueError('nonnegative integer duration required')
    if n==0:return 0
    k=1
    while n%10==0:n//=10;k*=10
    return k*int(str(n)[::-1])
def clean(x):
    if isinstance(x,F):return x.numerator if x.denominator==1 else str(x)
    if isinstance(x,dict):return {str(k):clean(v) for k,v in x.items()}
    if isinstance(x,(list,tuple)):return [clean(v) for v in x]
    return x
def begin(n,title,question,inputs,sources):
    previous=ROOT/'journal.json'
    rows=json.loads(previous.read_text()) if previous.exists() else []
    if n!=482+len(rows):raise ValueError('Sequential research step required')
    pending=ROOT/'pending.json'
    if pending.exists():
        saved=json.loads(pending.read_text())
        assert (saved['step'],saved['title'],saved['question'],saved['inputs'],saved['sources'])==(n,title,question,clean(inputs),sources)
        return saved
    item=dict(step=n,title=title,question=question,inputs=clean(inputs),sources=sources,
              opened_utc=datetime.datetime.now(datetime.timezone.utc).isoformat(),
              predecessor_sha256=rows[-1]['sha256'] if rows else 'C481:4d7a97cf35348c8ea23a23079b0682f739bb5b4b0cc734e24e7b9bc6e0b19455')
    (ROOT/'pending.json').write_text(json.dumps(item,indent=2)+'\n')
    return item
def finish(item,results,finding,next_question,checks):
    assert all(checks.values()),checks
    item.update(results=clean(results),finding=finding,reassessment=next_question,checks=checks,
                closed_utc=datetime.datetime.now(datetime.timezone.utc).isoformat())
    item['sha256']=hashlib.sha256(json.dumps(item,sort_keys=True).encode()).hexdigest()
    p=ROOT/'journal.json'; rows=json.loads(p.read_text()) if p.exists() else []
    rows.append(item);p.write_text(json.dumps(rows,indent=2,ensure_ascii=False)+'\n')
    (ROOT/'pending.json').unlink()
    print(json.dumps(dict(step=item['step'],results=item['results'],finding=finding,next=next_question),ensure_ascii=False))