import hashlib
import os

from app import app
from auth import hash_password
from tests.support import ApiTestCase, db_execute


class AuthTests(ApiTestCase):
    def session_token(self, client=None) -> str:
        return (
            (client or self.client)
            .get_cookie("sid", domain="localhost", path="/api")
            .value
        )

    def test_register_logs_in_and_me_returns_user(self):
        response = self.register("Alice")
        self.assertEqual(response.get_json(), {"id": 1, "username": "Alice"})
        me = self.call("GET", "/api/auth/me")
        self.assertEqual(me.status_code, 200)
        self.assertEqual(me.get_json(), {"id": 1, "username": "Alice"})

    def test_session_cookie_flags(self):
        cookie = self.register().headers["Set-Cookie"]
        for flag in ("HttpOnly", "Secure", "SameSite=Lax", "Path=/api"):
            self.assertIn(flag, cookie)

    def test_session_token_is_stored_hashed(self):
        self.register()
        digest = hashlib.sha256(self.session_token().encode()).digest()
        self.assertEqual(
            db_execute(
                "SELECT count(*) FROM sessions WHERE token_hash = %s", (digest,)
            )[0][0],
            1,
        )

    def test_duplicate_username_is_case_insensitive(self):
        self.register("Alice")
        response = self.call(
            "POST",
            "/api/auth/register",
            {"username": "alice", "password": "another long password"},
        )
        self.assertEqual(response.status_code, 409)
        self.assertEqual(response.get_json()["field"], "username")

    def test_register_validation(self):
        cases = [
            ({"username": "al", "password": "long enough password"}, "username"),
            ({"username": "al ice", "password": "long enough password"}, "username"),
            ({"username": "alice", "password": "short"}, "password"),
            ({"username": "alice", "password": "x" * 1025}, "password"),
            ({"username": "alice", "password": "\ud800" * 12}, "password"),
            (
                {
                    "username": "alice",
                    "password": "long enough password",
                    "is_admin": True,
                },
                "is_admin",
            ),
        ]
        for payload, field in cases:
            with self.subTest(payload=payload):
                response = self.call("POST", "/api/auth/register", payload)
                self.assertEqual(response.status_code, 400)
                self.assertEqual(response.get_json()["field"], field)

    def test_login_is_case_insensitive_on_username(self):
        self.register("Alice")
        self.client = app.test_client()  # fresh cookie jar: signed out
        response = self.call(
            "POST",
            "/api/auth/login",
            {"username": "ALICE", "password": "correct horse battery"},
        )
        self.assertEqual(response.status_code, 200)
        self.assertEqual(response.get_json(), {"id": 1, "username": "Alice"})

    def test_wrong_password_and_unknown_user_are_indistinguishable(self):
        self.register()
        wrong = self.call(
            "POST",
            "/api/auth/login",
            {"username": "alice", "password": "not the password"},
        )
        unknown = self.call(
            "POST",
            "/api/auth/login",
            {"username": "nobody", "password": "not the password"},
        )
        self.assertEqual(wrong.status_code, 401)
        self.assertEqual(unknown.status_code, 401)
        self.assertEqual(wrong.get_json(), unknown.get_json())
        self.assertEqual(wrong.get_json(), {"error": "Invalid username or password"})

    def test_login_with_malformed_username_is_401_not_500(self):
        response = self.call(
            "POST",
            "/api/auth/login",
            {"username": "a\x00b", "password": "whatever password"},
        )
        self.assertEqual(response.status_code, 401)

    def test_me_without_session_is_401(self):
        response = self.call("GET", "/api/auth/me")
        self.assertEqual(response.status_code, 401)
        self.assertEqual(
            response.get_json(),
            {"error": "Not signed in or session expired; log in again"},
        )

    def test_logout_revokes_token_server_side(self):
        self.register()
        token = self.session_token()
        self.assertEqual(self.call("POST", "/api/auth/logout").status_code, 204)
        self.client.set_cookie(
            "sid", token, domain="localhost", path="/api"
        )  # replay the stolen cookie
        self.assertEqual(self.call("GET", "/api/auth/me").status_code, 401)

    def test_idle_session_expires(self):
        self.register()
        db_execute("UPDATE sessions SET expires_at = now() - interval '1 second'")
        self.assertEqual(self.call("GET", "/api/auth/me").status_code, 401)

    def test_absolute_cap_applies_even_inside_idle_window(self):
        self.register()
        db_execute(
            "UPDATE sessions SET created_at = now() - interval '12 hours 1 second'"
        )
        self.assertEqual(self.call("GET", "/api/auth/me").status_code, 401)

    def test_activity_slides_idle_expiry(self):
        self.register()
        db_execute("UPDATE sessions SET expires_at = now() + interval '1 minute'")
        self.assertEqual(self.call("GET", "/api/auth/me").status_code, 200)
        remaining = db_execute(
            "SELECT expires_at - now() > interval '29 minutes' FROM sessions"
        )[0][0]
        self.assertTrue(remaining)

    def test_old_hash_is_upgraded_on_login(self):
        self.register()
        pepper = os.environ["PASSWORD_PEPPER"].encode()
        old = hash_password("correct horse battery", pepper, iterations=1000)
        db_execute("UPDATE users SET password_hash = %s", (old,))
        response = self.call(
            "POST",
            "/api/auth/login",
            {"username": "alice", "password": "correct horse battery"},
        )
        self.assertEqual(response.status_code, 200)
        self.assertTrue(
            db_execute("SELECT password_hash FROM users")[0][0].startswith(
                "pbkdf2_sha256$600000$"
            )
        )