"""pool_starvation, row_lock_contention, poison_data -- phase-0-base-project-spec.md
§7. All three are owned by `ledger`.
"""
from common.chaos_flags import is_enabled
from common.redis_client import redis_client

# Populated once by scripts/seed.py: account_id -> id of that account's one
# deliberately NULL-currency transaction (§8). A Redis hash lookup, not a
# `transactions` scan by account_id -- that column has no supporting index
# on purpose (§5), and the poison_data pathology shouldn't have to pay for a
# full-table seq scan on every single request just to find its own trigger.
POISON_TX_KEY = "poison:tx_by_account"


async def pool_starvation_enabled() -> bool:
    return await is_enabled("pool_starvation")


async def row_lock_contention_enabled() -> bool:
    return await is_enabled("row_lock_contention")


async def poison_data_enabled() -> bool:
    return await is_enabled("poison_data")


async def find_poison_transaction_id(account_id: str) -> str | None:
    return await redis_client.hget(POISON_TX_KEY, account_id)