"""Read-only aggregation of explicitly selected existing alias decisions.

Never calls an LLM, changes an answer, infers aliases, or silently chooses a judge.
"""
import argparse,collections,json
from pathlib import Path

def summarize(rows, field, error_policy):
    groups=collections.defaultdict(lambda:dict(rows=0,scored=0,correct=0,errors=0,unscored=0))
    seen=set()
    for r in rows:
        qid=r.get('qa_id');condition=r.get('condition',r.get('setting'))
        if not qid or not condition:raise ValueError('Every answer must have qa_id and condition/setting')
        key=(qid,condition)
        if key in seen:raise ValueError(f'Duplicate answer key: {key}; resolve explicitly before scoring')
        seen.add(key)
        error=bool(r.get('error') or r.get('api_error'))
        value=r.get(field)
        for group in [(condition,'Overall'),(condition,str(r.get('subtype') or 'unknown'))]:
            g=groups[group];g['rows']+=1;g['errors']+=int(error)
            if error and error_policy=='exclude':continue
            if error and error_policy=='count_as_incorrect':value=False
            if not isinstance(value,bool):g['unscored']+=1;continue
            g['scored']+=1;g['correct']+=int(value)
    result=[]
    for (c,s),g in sorted(groups.items()):
        result.append(dict(condition=c,subtype=s,**g,accuracy_pct=100*g['correct']/g['scored'] if g['scored'] else None))
    return dict(correct_field=field,error_policy=error_policy,unique_answer_keys=len(seen),groups=result)

def main():
    p=argparse.ArgumentParser(description=__doc__)
    p.add_argument('--answers',required=True,type=Path)
    p.add_argument('--correct-field',required=True)
    p.add_argument('--error-policy',required=True,choices=['exclude','count_as_incorrect','stored'])
    p.add_argument('--qa',type=Path,help='Optional exact evaluation QA subset; joins source_medium_qa_id or qa_id')
    p.add_argument('--out',required=True,type=Path)
    a=p.parse_args(); qa={}
    if a.qa:
        with a.qa.open(encoding='utf-8-sig') as f:
            for line in f:
                if not line.strip():continue
                r=json.loads(line);qid=r.get('source_medium_qa_id') or r['qa_id']
                if qid in qa:raise ValueError(f'Duplicate QA subset ID: {qid}')
                qa[qid]=r
        if not qa:raise ValueError('Explicit QA subset is empty; refusing full-set fallback')
    def records():
        with a.answers.open(encoding='utf-8-sig') as f:
            for line in f:
                if not line.strip():continue
                r=json.loads(line)
                if qa:
                    qid=r.get('source_medium_qa_id') or r['qa_id']
                    if qid not in qa:continue
                    r=dict(r,subtype=qa[qid].get('subtype',r.get('subtype')))
                yield r
    result=summarize(records(),a.correct_field,a.error_policy)
    result['qa_subset_size']=len(qa) if a.qa else None
    a.out.parent.mkdir(parents=True,exist_ok=True)
    a.out.write_text(json.dumps(result,ensure_ascii=False,indent=2),encoding='utf-8')
    print(json.dumps({'output':str(a.out),'keys':result['unique_answer_keys']}))
if __name__=='__main__':main()