"""Regression tests for B-04 (and the "building" half of B-08): a transaction that
never made it onto the chain must give the coins back instead of freezing them.

Also covers B-41: existence/reconciliation checks go through
blockchain.scripthash.get_history rather than a verbose blockchain.transaction.get
reply, so the fake clients below implement get_history.
"""

import pytest
from embit import script
from embit.transaction import Transaction, TransactionInput, TransactionOutput
from sqlalchemy import select
from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine

from app.config import settings
from app.db.base import Base
from app.db.models import AuditLog, PendingTransaction, RoundParticipant, User, UtxoEvent, Withdrawal
from app.tx.reconcile import reconcile_once


class UnknownTxClient:
    """A server whose history for any address never includes our txid."""

    async def get_history(self, scripthash: str) -> list[dict]:
        return []


class KnownTxClient:
    """A server whose history for the address includes our txid — mined or
    still in the mempool doesn't matter for existence, only for confirmation
    (which is tx/confirmation.py's concern, not reconcile.py's)."""

    def __init__(self, txid: str = "betxid"):
        self._txid = txid

    async def get_history(self, scripthash: str) -> list[dict]:
        return [{"tx_hash": self._txid, "height": 100}]


class BrokenClient:
    """A transport failure — says nothing about whether the tx exists."""

    async def get_history(self, scripthash: str) -> list[dict]:
        raise ConnectionResetError("connection reset")


@pytest.fixture
async def session_factory(tmp_path, monkeypatch):
    # own_address_for (B-41) derives each row's address via the HD wallet rather
    # than trusting the DB's address column, so reconcile_once now needs a real
    # master key set up — same bootstrap test_broadcast.py uses.
    monkeypatch.setattr(settings, "master_key_path", str(tmp_path / "master.xprv.enc"))
    monkeypatch.setattr(
        settings,
        "xprv_encryption_key",
        __import__("cryptography.fernet", fromlist=["Fernet"]).Fernet.generate_key().decode(),
    )
    from app.wallet import hd

    hd._account_key = None
    hd.generate_master_key()

    engine = create_async_engine("sqlite+aiosqlite:///:memory:")
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)
    yield async_sessionmaker(engine, expire_on_commit=False)
    await engine.dispose()
    hd._account_key = None


# A real (unsigned) transaction spending one input, built rather than hand-written
# so it round-trips through Transaction.parse — that parse is how the reconciler
# discovers which UTXOs to release, so a fixture the parser rejects would test
# nothing.
_TX_INPUT_TXID = "11" * 32
_RAW_TX = (
    Transaction(
        vin=[TransactionInput(bytes.fromhex(_TX_INPUT_TXID), 0)],
        vout=[
            TransactionOutput(
                999_000_000, script.Script.from_address("plm1q0xcqpzrky6eff2g52qdye53xkk9jxkvraxkkwd")
            )
        ],
    )
    .serialize()
    .hex()
)


async def _seed_bet(
    session_factory,
    *,
    pending_status: str,
    participant_status: str,
    age_seconds: int,
    last_broadcast_age_seconds: int | None = None,
    derivation_index: int = 0,
):
    from datetime import datetime, timedelta, timezone

    from app.wallet.hd import derive_user_address

    async with session_factory() as session:
        user = User(
            username="u",
            password_hash="x",
            derivation_index=derivation_index,
            address=derive_user_address(derivation_index),
        )
        session.add(user)
        await session.flush()
        session.add(
            UtxoEvent(
                user_id=user.id,
                txid=_TX_INPUT_TXID,
                vout=0,
                amount_sats=1_000_000_000,
                confirmed_height=10,
                spent_txid="betxid",
            )
        )
        session.add(
            RoundParticipant(
                round_id=1,
                user_id=user.id,
                bet_amount_sats=999_000_000,
                bet_txid="betxid",
                status=participant_status,
            )
        )
        # last_broadcast_age_seconds defaults to age_seconds (never bumped): the two
        # timestamps only diverge in the B-27 regression test below, which simulates
        # a tx that's been bumped recently but first appeared long ago.
        last_age = age_seconds if last_broadcast_age_seconds is None else last_broadcast_age_seconds
        session.add(
            PendingTransaction(
                kind="bet",
                round_id=1,
                user_id=user.id,
                current_txid="betxid",
                fee_rate_sat_vb=1,
                raw_tx_hex=_RAW_TX,
                status=pending_status,
                broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=age_seconds),
                last_broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=last_age),
            )
        )
        await session.commit()
        return user.id


async def test_abandons_a_building_bet_and_gives_the_coins_back(session_factory):
    """The crash-mid-broadcast case: the tx isn't on the chain, so the UTXO must be
    released, the participant removed (they never entered the round) and the balance
    restored. Before this existed, spent_txid stayed set forever and the user simply
    lost the coins."""
    user_id = await _seed_bet(
        session_factory, pending_status="building", participant_status="building", age_seconds=300
    )

    resolved = await reconcile_once(session_factory, UnknownTxClient())
    assert resolved == 1

    async with session_factory() as session:
        utxo = (await session.scalars(select(UtxoEvent))).one()
        assert utxo.spent_txid is None  # spendable again
        assert (await session.scalars(select(RoundParticipant))).all() == []
        row = (await session.scalars(select(PendingTransaction))).one()
        assert row.status == "failed"
        assert row.failure_reason
        user = await session.get(User, user_id)
        assert user.cached_balance_sats == 1_000_000_000
        events = [e.event_type for e in (await session.scalars(select(AuditLog))).all()]
        assert "pending_tx_abandoned" in events


async def test_promotes_a_building_row_whose_tx_did_reach_the_chain(session_factory):
    """We died after the broadcast, not before: the tx is real, so the rows must be
    finished rather than rolled back."""
    await _seed_bet(
        session_factory, pending_status="building", participant_status="building", age_seconds=300
    )

    resolved = await reconcile_once(session_factory, KnownTxClient("betxid"))
    assert resolved == 1

    async with session_factory() as session:
        row = (await session.scalars(select(PendingTransaction))).one()
        assert row.status == "pending"
        participant = (await session.scalars(select(RoundParticipant))).one()
        assert participant.status == "broadcast"
        utxo = (await session.scalars(select(UtxoEvent))).one()
        assert utxo.spent_txid == "betxid"  # still legitimately spent


async def test_leaves_a_young_building_row_alone(session_factory):
    """A row written seconds ago may just be a broadcast still in flight."""
    await _seed_bet(
        session_factory, pending_status="building", participant_status="building", age_seconds=5
    )

    assert await reconcile_once(session_factory, UnknownTxClient()) == 0

    async with session_factory() as session:
        assert (await session.scalars(select(PendingTransaction))).one().status == "building"


async def test_leaves_a_recently_broadcast_pending_row_alone(session_factory):
    """A broadcast tx gets a wide grace window — absence from one server's mempool
    is not proof of death, and the RBF bumper should get its attempts first."""
    await _seed_bet(
        session_factory, pending_status="pending", participant_status="broadcast", age_seconds=3600
    )

    assert await reconcile_once(session_factory, UnknownTxClient()) == 0


async def test_abandons_a_repeatedly_bumped_tx_despite_a_recent_last_broadcast(session_factory):
    """B-27 regression: before last_broadcast_at existed, bump_fee overwrote
    broadcast_at on every bump, which is the same field the abandon grace period is
    measured from — so a tx first seen long ago but bumped minutes ago (exactly what
    a stuck-but-repeatedly-bumped tx looks like) reset its own clock forever and was
    never abandoned. The reconciler must still abandon it based on when it *first*
    appeared, ignoring how recently it was last bumped."""
    await _seed_bet(
        session_factory,
        pending_status="pending",
        participant_status="broadcast",
        age_seconds=7 * 3600,  # first broadcast 7h ago — past the 6h abandon window
        last_broadcast_age_seconds=60,  # bumped a minute ago
    )

    assert await reconcile_once(session_factory, UnknownTxClient()) == 1

    async with session_factory() as session:
        assert (await session.scalars(select(PendingTransaction))).one().status == "failed"


async def test_transport_failure_never_abandons_anything(session_factory):
    """A dead connection says nothing about the transaction. Treating it as "gone"
    would release coins for transactions that are perfectly alive."""
    await _seed_bet(
        session_factory, pending_status="building", participant_status="building", age_seconds=300
    )

    assert await reconcile_once(session_factory, BrokenClient()) == 0

    async with session_factory() as session:
        assert (await session.scalars(select(PendingTransaction))).one().status == "building"
        assert (await session.scalars(select(UtxoEvent))).one().spent_txid == "betxid"


async def test_abandoned_withdrawal_is_marked_failed_and_kept(session_factory):
    """Unlike a bet, a withdrawal is an instruction the user gave: the row stays so
    they can see it didn't go through."""
    from datetime import datetime, timedelta, timezone

    from app.wallet.hd import derive_user_address

    async with session_factory() as session:
        user = User(username="w", password_hash="x", derivation_index=1, address=derive_user_address(1))
        session.add(user)
        await session.flush()
        session.add(
            UtxoEvent(
                user_id=user.id,
                txid=_TX_INPUT_TXID,
                vout=0,
                amount_sats=500_000_000,
                confirmed_height=10,
                spent_txid="wdtxid",
            )
        )
        withdrawal = Withdrawal(
            user_id=user.id,
            external_address="plm1qexternal",
            amount_requested_sats=400_000_000,
            amount_sent_sats=399_000_000,
            txid="wdtxid",
            status="broadcast",
        )
        session.add(withdrawal)
        await session.flush()
        session.add(
            PendingTransaction(
                kind="withdrawal",
                withdrawal_id=withdrawal.id,
                user_id=user.id,
                current_txid="wdtxid",
                fee_rate_sat_vb=1,
                raw_tx_hex=_RAW_TX,
                status="pending",
                broadcast_at=datetime.now(timezone.utc) - timedelta(days=1),
            )
        )
        await session.commit()

    assert await reconcile_once(session_factory, UnknownTxClient()) == 1

    async with session_factory() as session:
        withdrawal = (await session.scalars(select(Withdrawal))).one()
        assert withdrawal.status == "failed"
        assert withdrawal.txid is None
        assert (await session.scalars(select(UtxoEvent))).one().spent_txid is None


# --- B-41: existence checks now use get_history and share it across candidates
# sharing the same address, instead of a per-tx verbose blockchain.transaction.get. --


async def test_reconcile_once_caches_history_per_scripthash(session_factory):
    """Two payout PendingTransaction rows always share the same pool address —
    fetching its history twice in one pass would be wasteful and, at scale
    across many candidates on one address, needlessly slow the whole tick."""
    from datetime import datetime, timedelta, timezone

    async with session_factory() as session:
        old = datetime.now(timezone.utc) - timedelta(hours=7)
        session.add(
            PendingTransaction(
                kind="payout", round_id=1, current_txid="payout-a", fee_rate_sat_vb=1,
                raw_tx_hex=_RAW_TX, status="pending", broadcast_at=old, last_broadcast_at=old,
            )
        )
        session.add(
            PendingTransaction(
                kind="payout", round_id=2, current_txid="payout-b", fee_rate_sat_vb=1,
                raw_tx_hex=_RAW_TX, status="pending", broadcast_at=old, last_broadcast_at=old,
            )
        )
        await session.commit()

    call_count = {"n": 0}

    class CountingClient:
        async def get_history(self, scripthash: str) -> list[dict]:
            call_count["n"] += 1
            return [{"tx_hash": "payout-a", "height": 100}, {"tx_hash": "payout-b", "height": 100}]

    resolved = await reconcile_once(session_factory, CountingClient())

    assert resolved == 0  # both exist — nothing to abandon or promote (already "pending")
    assert call_count["n"] == 1  # one call covered both rows sharing the pool address