필드 근거·단위·사실 변경을 비교하는 합성 모듈

"""Synthetic price normalization and evidence-aware diff. No provider fetch."""
from decimal import Decimal,InvalidOperation
from datetime import date
import re
def normalized(value,unit):
 if not isinstance(value,str) or not re.fullmatch(r'\d{1,9}(?:\.\d{1,6})?',value):raise ValueError('bounded unsigned decimal text')
 if unit not in ('per_1k','per_1m'):raise ValueError('unit needs review')
 return format(Decimal(value)*(1000 if unit=='per_1k' else 1),'f')
def coverage(fields,evidence):
 if not isinstance(fields,dict) or not isinstance(evidence,list):raise ValueError('explicit fields and evidence')
 matched={k:[] for k in fields}
 for e in evidence:
  if set(e)!={'field','value','unit','reference','checked'} or not isinstance(e['reference'],str) or not e['reference'].strip():raise ValueError('evidence contract')
  date.fromisoformat(e['checked'])
  if e['field'] not in fields:raise ValueError('unknown field')
  row=fields[e['field']]
  if Decimal(normalized(row['value'],row['unit']))==Decimal(normalized(e['value'],e['unit'])):matched[e['field']].append(e['reference'])
 return dict(matches=matched,missing=sorted(k for k,v in matched.items() if not v),automatic_source_authentication=False)
def index(rows):
 result={}
 for r in rows:
  if set(r)!={'provider','model','input','output','checked','reference','note'}:raise ValueError('snapshot contract')
  if any(not isinstance(r[k],str) or not r[k].strip() for k in ('provider','model','reference')):raise ValueError('identifier/reference')
  key=(r['provider'],r['model'])
  if key in result:raise ValueError('duplicate composite identity')
  date.fromisoformat(r['checked'])
  for k in ('input','output'):normalized(r[k]['value'],r[k]['unit'])
  result[key]=r
 return result
def diff(before,after):
 a,b=index(before),index(after);changes=[]
 for key in sorted(a.keys()|b.keys()):
  if key not in a or key not in b:changes.append(dict(identity=list(key),kind='added' if key in b else 'removed'));continue
  values=[k for k in ('input','output') if Decimal(normalized(a[key][k]['value'],a[key][k]['unit']))!=Decimal(normalized(b[key][k]['value'],b[key][k]['unit']))]
  metadata=[k for k in ('checked','reference','note') if a[key][k]!=b[key][k]]
  representation=[k for k in ('input','output') if a[key][k]!=b[key][k]]
  if values or metadata or representation:changes.append(dict(identity=list(key),kind='value_changed' if values else 'verification_or_representation_only',value_fields=values,metadata_fields=metadata,representation_fields=representation))
 return changes