"""修复 reserved_balance 冻结漂移(审计 I2)存量坏账。

根因:CreditReservation.task 是 OneToOneField(on_delete=CASCADE) —— 删任务/删项目
级联删掉 ACTIVE 预留行,但 account.reserved_balance 冻结的份额永不归还。代码侧已由
apps/billing/signals.py 的 pre_delete 守护堵住;本脚本回填历史漂移:
    对每个账户,在行锁事务内令 reserved_balance = Σ(ACTIVE 预留),差额落一条 RELEASE
    流水(task/user 为空,reason 注明修复),与 release_credit 的记账口径一致。

跑法(默认 dry-run 只报告;--apply 才写库):
  cd backend && DJANGO_SETTINGS_MODULE=airshelf.settings.development \
      .venv/bin/python ../qa/repair_reserved_drift.py [--apply]
"""
import os
import sys
from decimal import Decimal

sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "backend"))
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "airshelf.settings.development")
import django  # noqa: E402

django.setup()

from django.db import transaction  # noqa: E402
from django.db.models import Sum  # noqa: E402

from apps.billing.models import CreditAccount, CreditLedger, CreditReservation  # noqa: E402

apply_mode = "--apply" in sys.argv
fixed = 0
for account_id in CreditAccount.objects.values_list("id", flat=True):
    with transaction.atomic():
        account = CreditAccount.objects.select_for_update().get(id=account_id)
        active_sum = (
            CreditReservation.objects.filter(team=account.team, status=CreditReservation.Status.ACTIVE)
            .aggregate(s=Sum("amount"))["s"] or Decimal("0")
        )
        drift = account.reserved_balance - active_sum
        if drift == 0:
            continue
        print(f"[{account.team}] reserved={account.reserved_balance} ACTIVEΣ={active_sum} 漂移={drift}"
              f" -> {'修复' if apply_mode else 'dry-run 不写'}")
        if drift < 0:
            # reserved 比 ACTIVE 还小属另一种坏账(理论不该出现),不自动动,人工核
            print("  !! 漂移为负,跳过(需人工核查)")
            continue
        if not apply_mode:
            continue
        account.reserved_balance = active_sum
        account.save(update_fields=["reserved_balance", "updated_at"])
        CreditLedger.objects.create(
            team=account.team,
            ledger_type=CreditLedger.Type.RELEASE,
            amount=drift,
            balance_after=account.balance,
            reason="修复:任务删除级联吞预留的历史漂移回填(I2)",
            metadata={"kind": "repair_reserved_drift"},
        )
        fixed += 1
print(f"\n{'已修复' if apply_mode else '待修复(dry-run)'}账户数:{fixed if apply_mode else '见上'}")