"""Integration test fixtures (TEST-02).

The configured DB user lacks `CREATE DATABASE` privilege, so a literal
second MySQL schema isn't available here. Instead, each test runs inside a
SAVEPOINT-nested transaction against the real configured database that is
*always rolled back* at the end of the test (SQLAlchemy's documented
"join a Session into an external transaction" recipe) -- route handlers'
internal `db.commit()` calls only release the savepoint, they never commit
the outer transaction, so nothing a test writes is ever actually persisted.
This achieves the requirement's real goal (integration tests never leave
data behind in the database other code reads) without needing a schema the
credentials can't create.

Note: the app's lifespan startup calls `seed_officer_if_missing`, which
runs against the *real* engine (via `session_scope()`), not the
savepoint-wrapped test session -- so the seed officer row is a genuine,
persistent row (idempotent: it no-ops if already present), not test data
that gets rolled back. That's intentional and matches production behavior.
"""

from __future__ import annotations

import app.auth as auth_module
import pytest
from fastapi.testclient import TestClient
from sqlalchemy import event

from app.config import settings
from app.db.session import SessionLocal, engine, get_session
from app.main import app

# TestClient's default base URL is http://testserver -- a "Secure" cookie
# (correct for the real deployment behind an HTTPS reverse proxy) would
# never be sent back over that scheme, breaking every authenticated request
# in tests. Same fix as local dev: force it off for the test process.
auth_module.COOKIE_SECURE = False


@pytest.fixture()
def db_session():
    connection = engine.connect()
    outer_transaction = connection.begin()
    session = SessionLocal(bind=connection, autoflush=False, autocommit=False)

    nested = connection.begin_nested()

    @event.listens_for(session, "after_transaction_end")
    def _restart_savepoint(sess, transaction):
        nonlocal nested
        if not nested.is_active:
            nested = connection.begin_nested()

    try:
        yield session
    finally:
        session.close()
        outer_transaction.rollback()
        connection.close()


@pytest.fixture()
def api_client(db_session):
    def _override_get_session():
        yield db_session

    app.dependency_overrides[get_session] = _override_get_session
    with TestClient(app) as test_client:
        yield test_client
    app.dependency_overrides.pop(get_session, None)


def login(api_client: TestClient, email: str, password: str) -> dict:
    """Logs in and returns `{"cookies": {...}}` for use as
    `api_client.get(url, cookies=identity["cookies"])` -- lets a single
    TestClient (one shared DB transaction) act as several logged-in
    identities at once without re-running the (expensive, model-loading)
    lifespan per identity.
    """
    res = api_client.post("/api/auth/login", json={"email": email, "password": password})
    assert res.status_code == 200, res.text
    token = res.cookies.get("session_token")
    return {"cookies": {"session_token": token}, "user": res.json()}


@pytest.fixture()
def officer_identity(api_client):
    return login(api_client, settings.SEED_OFFICER_EMAIL, settings.SEED_OFFICER_PASSWORD)


def create_client(api_client: TestClient, officer_identity: dict, *, email: str, name: str, balance: float = 5000) -> dict:
    res = api_client.post(
        "/api/officer/clients",
        json={
            "name": name,
            "email": email,
            "temp_password": "TempPass123!",
            "starting_balance": balance,
            "account_type": "checking",
        },
        cookies=officer_identity["cookies"],
    )
    assert res.status_code == 200, res.text
    body = res.json()
    identity = login(api_client, email, "TempPass123!")
    identity["client_id"] = body["client"]["id"]
    return identity


@pytest.fixture()
def two_clients(api_client, officer_identity):
    """Two client identities with distinct starting balances, per the
    role-separation testing requirement (one seeded officer, two seeded
    clients)."""
    client_a = create_client(
        api_client, officer_identity, email="fixture.alpha@fakebankmail.com", name="Fixture Alpha", balance=5000
    )
    client_b = create_client(
        api_client, officer_identity, email="fixture.beta@fakebankmail.com", name="Fixture Beta", balance=3000
    )
    return client_a, client_b


TRANSFER_FRAUD_PATTERN = {
    "step": 5,
    "type": "TRANSFER",
    "amount": 181.0,
    "nameOrig": "CTEST_FRAUD_ORIG",
    "oldbalanceOrg": 181.0,
    "newbalanceOrig": 0.0,
    "nameDest": "CTEST_FRAUD_DEST",
    "oldbalanceDest": 0.0,
    "newbalanceDest": 0.0,
}

PAYMENT_LEGIT_PATTERN = {
    "step": 5,
    "type": "PAYMENT",
    "amount": 50.0,
    "nameOrig": "CTEST_LEGIT_ORIG",
    "oldbalanceOrg": 5000.0,
    "newbalanceOrig": 4950.0,
    "nameDest": "MTEST_MERCHANT",
    "oldbalanceDest": 0.0,
    "newbalanceDest": 0.0,
}