import pytest
from sqlalchemy import select
from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine

from app.db.base import Base
from app.db.models import AuditLog, User, UtxoEvent
from app.deposits.service import credit_confirmed_utxos, detect_external_spends


@pytest.fixture
async def session_factory():
    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()


@pytest.fixture
async def user_id(session_factory):
    async with session_factory() as session:
        user = User(username="alice", password_hash="x", derivation_index=0, address="plm1qxxx")
        session.add(user)
        await session.commit()
        return user.id


async def test_credits_confirmed_utxo_and_updates_balance(session_factory, user_id):
    entries = [{"tx_hash": "aa" * 32, "tx_pos": 0, "height": 100, "value": 10_000_000}]
    async with session_factory() as session:
        credited = await credit_confirmed_utxos(session, user_id, entries)
        assert credited == 1
        user = await session.get(User, user_id)
        assert user.cached_balance_sats == 10_000_000


async def test_unconfirmed_entry_is_ignored(session_factory, user_id):
    entries = [{"tx_hash": "bb" * 32, "tx_pos": 0, "height": 0, "value": 5_000_000}]
    async with session_factory() as session:
        credited = await credit_confirmed_utxos(session, user_id, entries)
        assert credited == 0
        user = await session.get(User, user_id)
        assert user.cached_balance_sats == 0


async def test_idempotent_on_repeated_notification(session_factory, user_id):
    entries = [{"tx_hash": "cc" * 32, "tx_pos": 0, "height": 100, "value": 7_000_000}]
    async with session_factory() as session:
        first = await credit_confirmed_utxos(session, user_id, entries)
    async with session_factory() as session:
        second = await credit_confirmed_utxos(session, user_id, entries)
        user = await session.get(User, user_id)
        assert first == 1
        assert second == 0
        assert user.cached_balance_sats == 7_000_000


async def test_external_spend_marks_utxo_spent_and_corrects_balance(session_factory, user_id):
    entries = [{"tx_hash": "dd" * 32, "tx_pos": 0, "height": 100, "value": 20_000_000}]
    async with session_factory() as session:
        await credit_confirmed_utxos(session, user_id, entries)

    async with session_factory() as session:
        spent = await detect_external_spends(session, user_id, [])
        assert spent == 1
        user = await session.get(User, user_id)
        assert user.cached_balance_sats == 0

        utxo = (await session.scalars(select(UtxoEvent).where(UtxoEvent.user_id == user_id))).one()
        assert utxo.spent_txid == "external-spend"

        audit_events = (await session.scalars(select(AuditLog))).all()
        assert any(e.event_type == "utxo_spent_externally" for e in audit_events)


async def test_no_spend_detected_when_utxo_still_unspent(session_factory, user_id):
    entries = [{"tx_hash": "ee" * 32, "tx_pos": 0, "height": 100, "value": 3_000_000}]
    async with session_factory() as session:
        await credit_confirmed_utxos(session, user_id, entries)

    async with session_factory() as session:
        spent = await detect_external_spends(session, user_id, entries)
        assert spent == 0
        user = await session.get(User, user_id)
        assert user.cached_balance_sats == 3_000_000