"""Integration tests for the auth endpoints (register + login).

These tests hit the real FastAPI app against the real configured database
(DATABASE_URL -- Postgres via Alembic migrations in CI/dev, not an isolated
in-memory DB), so they exercise the full stack: Pydantic validation → DB →
JWT → response. Requires migrations already applied (alembic upgrade head)
before running.
"""

import pytest
from fastapi.testclient import TestClient
from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
from sqlalchemy.pool import NullPool

from app.config import settings
from app.main import app
from app.database import get_db
from app.routers.auth import pwd_context


# ---------------------------------------------------------------------------
# Test fixtures
# ---------------------------------------------------------------------------

@pytest.fixture(autouse=True)
def _override_db():
    """Override get_db so the app uses a fresh session per test.

    Deliberately does NOT reuse app.database's shared engine: FastAPI's
    (sync) TestClient runs each request through anyio's blocking-portal
    machinery, which can hand different requests different event loops.
    asyncpg connections are bound to the loop they were created on, so
    reusing one from the shared engine's connection pool across requests
    raises "cannot perform operation: another operation is in progress" the
    moment a test makes more than one request (register-then-login,
    register-twice, etc.) -- confirmed this is the actual cause, not a bug
    in the endpoints themselves. NullPool sidesteps it: every checkout is a
    brand-new connection, never handed to a different loop than the one
    that opened it.
    """
    test_engine = create_async_engine(settings.DATABASE_URL, poolclass=NullPool)
    test_session_factory = async_sessionmaker(test_engine, expire_on_commit=False)

    async def _get_db():
        async_session = test_session_factory()
        try:
            yield async_session
            await async_session.commit()
        except Exception:
            await async_session.rollback()
            raise
        finally:
            await async_session.close()

    app.dependency_overrides[get_db] = _get_db
    yield
    app.dependency_overrides.clear()


# ---------------------------------------------------------------------------
# Register endpoint
# ---------------------------------------------------------------------------

class TestRegister:
    """Tests for POST /api/auth/register."""

    def test_register_success(self):
        """A valid registration returns 201 with a token."""
        client = TestClient(app)
        resp = client.post(
            "/api/auth/register",
            json={
                "username": "newuser",
                "email": "new@example.com",
                "password": "secret123",
                "date_of_birth": "1990-01-01",
            },
        )
        assert resp.status_code == 201
        data = resp.json()
        assert "access_token" in data
        assert data["token_type"] == "bearer"

    def test_register_rejects_under_18(self):
        """A DOB that computes to under 18 gets a 403 (see test_auth_age_gate
        for the age-math coverage)."""
        from datetime import date
        client = TestClient(app)
        minor_dob = date.today().replace(year=date.today().year - 14).isoformat()
        resp = client.post(
            "/api/auth/register",
            json={
                "username": "kid",
                "email": "kid@example.com",
                "password": "secret123",
                "date_of_birth": minor_dob,
            },
        )
        assert resp.status_code == 403
        assert "at least 18" in resp.json()["detail"]

    def test_register_rejects_duplicate_username(self):
        """Registering the same username twice returns 409."""
        client = TestClient(app)
        # First registration
        client.post(
            "/api/auth/register",
            json={
                "username": "duplicate",
                "email": "dup1@example.com",
                "password": "secret123",
                "date_of_birth": "1990-01-01",
            },
        )
        # Second registration with same username, different email
        resp = client.post(
            "/api/auth/register",
            json={
                "username": "duplicate",
                "email": "dup2@example.com",
                "password": "secret123",
                "date_of_birth": "1990-01-01",
            },
        )
        assert resp.status_code == 409
        assert "Username already registered" in resp.json()["detail"]

    def test_register_rejects_duplicate_email(self):
        """Registering the same email twice returns 409."""
        client = TestClient(app)
        client.post(
            "/api/auth/register",
            json={
                "username": "user1",
                "email": "same@example.com",
                "password": "secret123",
                "date_of_birth": "1990-01-01",
            },
        )
        resp = client.post(
            "/api/auth/register",
            json={
                "username": "user2",
                "email": "same@example.com",
                "password": "secret123",
                "date_of_birth": "1990-01-01",
            },
        )
        assert resp.status_code == 409
        assert "Email already registered" in resp.json()["detail"]

    def test_register_missing_dob(self):
        """Missing the required date_of_birth field returns 422."""
        client = TestClient(app)
        resp = client.post(
            "/api/auth/register",
            json={
                "username": "user",
                "email": "user@example.com",
                "password": "secret123",
            },
        )
        assert resp.status_code == 422


# ---------------------------------------------------------------------------
# Login endpoint
# ---------------------------------------------------------------------------

class TestLogin:
    """Tests for POST /api/auth/login."""

    def _create_user(self, username: str, password: str, email: str = None):
        """Helper to create a user via register."""
        client = TestClient(app)
        if email is None:
            email = f"{username}@example.com"
        resp = client.post(
            "/api/auth/register",
            json={
                "username": username,
                "email": email,
                "password": password,
                "date_of_birth": "1990-01-01",
            },
        )
        assert resp.status_code == 201
        return resp.json()["access_token"]

    def test_login_success(self):
        """Correct credentials return a token."""
        self._create_user("loginuser", "correctpass")
        client = TestClient(app)
        resp = client.post(
            "/api/auth/login",
            data={"username": "loginuser", "password": "correctpass"},
        )
        assert resp.status_code == 200
        data = resp.json()
        assert "access_token" in data
        assert data["token_type"] == "bearer"

    def test_login_wrong_password(self):
        """Wrong password returns 401."""
        # Distinct username from test_login_success -- there's no per-test
        # DB rollback/isolation here (real Postgres via the app's own
        # dependency-overridden session), so reusing "loginuser" collided
        # with the user that test already created (409 on register instead
        # of the intended 401-on-login assertion this test is actually for).
        self._create_user("loginuser_wrongpass", "correctpass")
        client = TestClient(app)
        resp = client.post(
            "/api/auth/login",
            data={"username": "loginuser_wrongpass", "password": "wrongpass"},
        )
        assert resp.status_code == 401
        assert "Incorrect username or password" in resp.json()["detail"]

    def test_login_nonexistent_user(self):
        """Non-existent user returns 401 (not 404)."""
        client = TestClient(app)
        resp = client.post(
            "/api/auth/login",
            data={"username": "nobody", "password": "any"},
        )
        assert resp.status_code == 401
        assert "Incorrect username or password" in resp.json()["detail"]

    def test_login_accepts_form_encoded(self):
        """Login accepts application/x-www-form-urlencoded (OAuth2)."""
        self._create_user("formuser", "formpass")
        client = TestClient(app)
        resp = client.post(
            "/api/auth/login",
            data={"username": "formuser", "password": "formpass"},
        )
        assert resp.status_code == 200
        assert "access_token" in resp.json()

    def test_login_token_is_valid_jwt(self):
        """The returned token is a valid JWT that can be decoded."""
        self._create_user("jwttoken", "jwt123")
        client = TestClient(app)
        resp = client.post(
            "/api/auth/login",
            data={"username": "jwttoken", "password": "jwt123"},
        )
        token = resp.json()["access_token"]
        # Verify it's a 3-part JWT
        parts = token.split(".")
        assert len(parts) == 3