import pytest
from itsdangerous import Signer

def _cookie_value(response, name="session"):
    header = response.headers.get("Set-Cookie")
    assert header is not None, "no Set-Cookie header was sent"
    assert header.startswith(f"{name}=")
    return header[len(name) + 1:].split(";", 1)[0]

@pytest.mark.asyncio
async def test_unsigned_cookie_is_plain_sid(app_factory):
    """Regression: str sid used to blow up with AttributeError on .decode()."""
    app = app_factory(SESSION_USE_SIGNER=False)
    client = app.test_client()

    response = await client.get("/")

    assert response.status_code == 200
    data = await response.get_json()
    assert data["hits"] == 1
    assert _cookie_value(response) == data["sid"]

@pytest.mark.asyncio
async def test_signed_cookie_is_signed_sid(app_factory):
    app = app_factory(SESSION_USE_SIGNER=True)
    client = app.test_client()

    response = await client.get("/")

    assert response.status_code == 200
    data = await response.get_json()
    cookie = _cookie_value(response)
    assert cookie != data["sid"]

    signer = Signer(app.secret_key, salt="quart-session",
                    key_derivation="hmac")
    assert signer.unsign(cookie).decode() == data["sid"]

@pytest.mark.asyncio
@pytest.mark.parametrize("use_signer", [False, True])
async def test_session_survives_next_request(app_factory, use_signer):
    app = app_factory(SESSION_USE_SIGNER=use_signer)
    client = app.test_client()

    first = await client.get("/")
    second = await client.get("/")

    assert (await first.get_json())["hits"] == 1
    assert (await second.get_json())["hits"] == 2

@pytest.mark.asyncio
async def test_signer_without_secret_key_sets_no_cookie(app_factory):
    app = app_factory(SESSION_USE_SIGNER=True)
    app.secret_key = None
    client = app.test_client()

    response = await client.get("/")

    assert response.status_code == 200
    assert response.headers.get("Set-Cookie") is None