"""Deterministic queue arithmetic, not a database or load-test benchmark."""
import csv, heapq, json
from pathlib import Path
p=Path(__file__).parent
rows=[]
for scenario,size,borrow,hold,external_inside in [('held_remote',4,0,840,True),('larger_pool',8,0,840,True),('remote_first',4,800,40,False)]:
    slots=[(0,i) for i in range(size)];heapq.heapify(slots)
    for request in range(1,13):
        free,slot=heapq.heappop(slots);acquired=max(free,borrow);released=acquired+hold
        rows.append(dict(scenario=scenario,request=request,slot=slot,borrow_requested_ms=borrow,acquired_ms=acquired,released_ms=released,pool_wait_ms=acquired-borrow,hold_ms=hold,sql_ms=40,remote_start_ms=acquired+20 if external_inside else 0,remote_end_ms=acquired+820 if external_inside else 800))
        heapq.heappush(slots,(released,slot))
summary=[]
for name in ['held_remote','larger_pool','remote_first']:
    subset=[r for r in rows if r['scenario']==name]
    summary.append(dict(scenario=name,max_pool_wait_ms=max(r['pool_wait_ms'] for r in subset),last_completion_ms=max(r['released_ms'] for r in subset)))
assert [(r['max_pool_wait_ms'],r['last_completion_ms']) for r in summary]==[(1680,2520),(840,1680),(80,920)]
(p/'queue-results.json').write_text(json.dumps({'kind':'deterministic model','assumptions':{'requests':12,'arrival_ms':0,'sql_total_ms':40,'remote_ms':800,'database_contention':False,'external_concurrency_limit':None},'summary':summary,'requests':rows},indent=2)+'\n')
with (p/'queue-trace.csv').open('w',newline='') as f:
    writer=csv.DictWriter(f,fieldnames=rows[0]);writer.writeheader();writer.writerows(rows)
print(json.dumps(summary,indent=2))