import os
from unittest import mock

import pytest
from fastapi.testclient import TestClient
from sqlalchemy import StaticPool, create_engine, event
from sqlalchemy.orm import sessionmaker

from allmende_payment_system.api.dependencies import get_session
from allmende_payment_system.app import app
from allmende_payment_system.models import Base

engine = create_engine(
    "sqlite:///:memory:",
    connect_args={"check_same_thread": False},
    poolclass=StaticPool,
)

# Create a single connection and an outer transaction which we can rollback
# at the end of the test run. Individual tests will use nested transactions
# (SAVEPOINTs) for isolation. This ensures the TestClient (app) and the
# test fixture sessions see the same in-memory database state.
connection = engine.connect()
transaction = connection.begin()

Base.metadata.create_all(bind=connection)

# Bind sessions to the single connection so all sessions share the same DB
TestSessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=connection)

test_session = None


def get_test_session():
    """Dependency override for get_session"""
    assert test_session is not None, "test_session is not set"
    yield test_session
    test_session.flush()


app.dependency_overrides[get_session] = get_test_session


@pytest.fixture(scope="session")
def client():
    os.environ["APS_username"] = "test"
    return TestClient(app)


@pytest.fixture(scope="session")
def unauthorized_client():
    os.environ.pop("APS_username", None)
    return TestClient(app)


@pytest.fixture(scope="function")
def test_db():
    """Provides a database session for direct test usage"""
    db = TestSessionLocal()
    global test_session
    test_session = db
    try:
        yield db
    finally:
        test_session = None
        db.rollback()
        db.close()