"""Tests for the auth router (POST /api/auth/login, POST /api/auth/logout)."""

from __future__ import annotations

import asyncio
from collections.abc import Generator
from unittest.mock import patch

import pytest
from httpx import AsyncClient

from app.utils.constants import SESSION_COOKIE_NAME

# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

_SETUP_PAYLOAD = {
    "master_password": "Mysecretpass1!",
    "database_path": "bangui.db",
    "fail2ban_socket": "/var/run/fail2ban/fail2ban.sock",
    "timezone": "UTC",
    "session_duration_minutes": 60,
}


async def _do_setup(client: AsyncClient) -> None:
    """Run the setup wizard so auth endpoints are reachable."""
    resp = await client.post("/api/v1/setup", json=_SETUP_PAYLOAD)
    assert resp.status_code == 201


async def _login(client: AsyncClient, password: str = "Mysecretpass1!") -> str:
    """Helper: perform login and return the session token from the cookie.

    Note: The token is returned in the HttpOnly cookie, not in the JSON body.
    For testing Bearer token auth, we extract it from the cookie.
    """
    resp = await client.post("/api/v1/auth/login", json={"password": password})
    assert resp.status_code == 200
    token = resp.cookies.get(SESSION_COOKIE_NAME)
    assert token is not None
    return str(token)


# ---------------------------------------------------------------------------
# Login
# ---------------------------------------------------------------------------


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

    async def test_login_succeeds_with_correct_password(
        self, client: AsyncClient
    ) -> None:
        """Login returns 200 and sets a session cookie for the correct password."""
        await _do_setup(client)
        response = await client.post(
            "/api/v1/auth/login", json={"password": "Mysecretpass1!"}
        )
        assert response.status_code == 200
        body = response.json()
        # Token is not returned in the JSON body; it's set as an HttpOnly cookie
        assert "token" not in body
        assert "expires_at" in body

    async def test_login_sets_cookie(self, client: AsyncClient) -> None:
        """Login sets the bangui_session HttpOnly cookie."""
        await _do_setup(client)
        response = await client.post(
            "/api/v1/auth/login", json={"password": "Mysecretpass1!"}
        )
        assert response.status_code == 200
        assert SESSION_COOKIE_NAME in response.cookies
        assert "." in response.cookies[SESSION_COOKIE_NAME]
        set_cookie = response.headers.get("set-cookie", "")
        assert "HttpOnly" in set_cookie
        assert "SameSite=lax" in set_cookie

    async def test_login_sets_secure_cookie_when_enabled(
        self, client: AsyncClient
    ) -> None:
        """Login sets the Secure flag when session cookies are configured for HTTPS."""
        client._transport.app.state.settings.session_cookie_secure = True
        await _do_setup(client)
        response = await client.post(
            "/api/v1/auth/login", json={"password": "Mysecretpass1!"}
        )
        assert response.status_code == 200
        set_cookie = response.headers.get("set-cookie", "")
        assert "Secure" in set_cookie

    async def test_login_fails_with_wrong_password(
        self, client: AsyncClient
    ) -> None:
        """Login returns 401 for an incorrect password."""
        await _do_setup(client)
        response = await client.post(
            "/api/v1/auth/login", json={"password": "wrongpassword"}
        )
        assert response.status_code == 401

    async def test_login_rejects_empty_password(self, client: AsyncClient) -> None:
        """Login returns 422 when password field is missing."""
        await _do_setup(client)
        response = await client.post("/api/v1/auth/login", json={})
        assert response.status_code == 422

    async def test_login_rate_limit_returns_429_after_5_attempts(
        self, client: AsyncClient
    ) -> None:
        """Login is blocked immediately after first failed attempt due to exponential backoff."""
        await _do_setup(client)
        limiter = client._transport.app.state.login_rate_limiter
        limiter.reset()

        # First failed attempt is allowed
        response = await client.post(
            "/api/v1/auth/login", json={"password": "wrongpassword"}
        )
        assert response.status_code == 401

        # Second attempt immediately after is blocked by 1s penalty
        response = await client.post(
            "/api/v1/auth/login", json={"password": "wrongpassword"}
        )
        assert response.status_code == 429
        assert response.json()["detail"] == "Too many login attempts. Please try again later."

        # Verify the failure count is correct
        state = limiter.get_state()
        assert "127.0.0.1" in state
        assert state["127.0.0.1"] >= 1

    async def test_login_rate_limit_includes_retry_after_header(
        self, client: AsyncClient
    ) -> None:
        """Rate-limited response includes Retry-After header."""
        await _do_setup(client)
        limiter = client._transport.app.state.login_rate_limiter
        limiter.reset()

        # First attempt fails
        response = await client.post("/api/v1/auth/login", json={"password": "wrong"})
        assert response.status_code == 401

        # Second immediate attempt is rate-limited
        response = await client.post("/api/v1/auth/login", json={"password": "wrong"})
        assert response.status_code == 429
        assert "retry-after" in response.headers
        assert response.headers["retry-after"] == "60"

    async def test_login_rate_limit_per_ip(
        self, client: AsyncClient
    ) -> None:
        """Rate limit is tracked separately per IP address."""
        await _do_setup(client)
        limiter = client._transport.app.state.login_rate_limiter
        limiter.reset()

        # Make 1 failed attempt with default IP
        response = await client.post("/api/v1/auth/login", json={"password": "wrong"})
        assert response.status_code == 401

        # 2nd attempt is blocked
        response = await client.post(
            "/api/v1/auth/login", json={"password": "correct"}
        )
        assert response.status_code == 429

        # Verify the failure count is correct
        state = limiter.get_state()
        assert "127.0.0.1" in state
        assert state["127.0.0.1"] >= 1

    async def test_login_rate_limit_reset_after_window(
        self, client: AsyncClient
    ) -> None:
        """Rate limit counter resets after the window expires."""
        await _do_setup(client)
        limiter = client._transport.app.state.login_rate_limiter
        limiter.reset()

        # Make 1 failed attempt (enough to trigger exponential backoff)
        response = await client.post("/api/v1/auth/login", json={"password": "wrong"})
        assert response.status_code == 401

        # 2nd attempt is blocked
        response = await client.post(
            "/api/v1/auth/login", json={"password": "wrong"}
        )
        assert response.status_code == 429

        # Reset the limiter (simulate window expiry)
        limiter.reset()

        # Now a fresh login attempt should succeed (use correct password)
        response = await client.post(
            "/api/v1/auth/login", json={"password": "Mysecretpass1!"}
        )
        assert response.status_code == 200

    async def test_login_exponential_backoff(self, client: AsyncClient) -> None:
        """Exponential backoff accumulates with each consecutive failure."""
        await _do_setup(client)
        limiter = client._transport.app.state.login_rate_limiter
        limiter.reset()

        # 1st failure: 1 * 2^1 = 2s penalty
        response = await client.post("/api/v1/auth/login", json={"password": "wrong"})
        assert response.status_code == 401
        state = limiter.get_state()
        assert state["127.0.0.1"] == 1

        # 2nd attempt blocked immediately by 2s penalty
        response = await client.post("/api/v1/auth/login", json={"password": "wrong"})
        assert response.status_code == 429

        # After 2.1s, the penalty expires and we can try again
        # (this will record a 2nd failure, creating a 1 * 2^2 = 4s penalty)
        await asyncio.sleep(2.1)
        response = await client.post("/api/v1/auth/login", json={"password": "wrong"})
        assert response.status_code == 401
        state = limiter.get_state()
        assert state["127.0.0.1"] == 2

        # Now blocked by 4s penalty
        response = await client.post("/api/v1/auth/login", json={"password": "wrong"})
        assert response.status_code == 429


# ---------------------------------------------------------------------------
# Logout
# ---------------------------------------------------------------------------


class TestLogout:
    """POST /api/auth/logout."""

    async def test_logout_returns_200(self, client: AsyncClient) -> None:
        """Logout returns 200 with a confirmation message."""
        await _do_setup(client)
        await _login(client)
        response = await client.post("/api/v1/auth/logout")
        assert response.status_code == 200
        assert "message" in response.json()

    async def test_logout_clears_cookie(self, client: AsyncClient) -> None:
        """Logout clears the bangui_session cookie."""
        await _do_setup(client)
        await _login(client)  # sets cookie on client
        response = await client.post("/api/v1/auth/logout")
        assert response.status_code == 200
        # Cookie should be set to empty / deleted in the Set-Cookie header.
        set_cookie = response.headers.get("set-cookie", "")
        assert SESSION_COOKIE_NAME in set_cookie

    async def test_logout_is_idempotent(self, client: AsyncClient) -> None:
        """Logout succeeds even when called without a session token."""
        await _do_setup(client)
        response = await client.post("/api/v1/auth/logout")
        assert response.status_code == 200

    async def test_session_invalid_after_logout(
        self, client: AsyncClient
    ) -> None:
        """A session token is rejected after logout."""
        await _do_setup(client)
        token = await _login(client)

        await client.post("/api/v1/auth/logout")

        # Now try to use the invalidated token via Bearer header.  The health
        # endpoint is unprotected so we validate against a hypothetical
        # protected endpoint by inspecting the auth service directly.
        # Here we just confirm the token is no longer in the DB by trying
        # to re-use it on logout (idempotent — still 200, not an error).
        response = await client.post(
            "/api/v1/auth/logout",
            headers={"Authorization": f"Bearer {token}"},
        )
        assert response.status_code == 200


# ---------------------------------------------------------------------------
# Auth dependency (protected route guard)
# ---------------------------------------------------------------------------


class TestRequireAuth:
    """Verify the require_auth dependency rejects unauthenticated requests."""

    async def test_health_endpoint_requires_no_auth(
        self, client: AsyncClient
    ) -> None:
        """Health endpoint is accessible without authentication."""
        response = await client.get("/api/v1/health")
        assert response.status_code == 200

    async def test_session_cache_is_disabled_by_default(
        self, client: AsyncClient
    ) -> None:
        """Session validation does not use the in-memory cache unless enabled."""
        from app.repositories import session_repo

        await _do_setup(client)
        token = await _login(client)

        call_count = 0
        original_get_session = session_repo.get_session

        async def _tracking(db, tok):  # type: ignore[no-untyped-def]
            nonlocal call_count
            call_count += 1
            return await original_get_session(db, tok)

        with patch.object(session_repo, "get_session", side_effect=_tracking):
            resp1 = await client.get(
                "/api/v1/dashboard/status",
                headers={"Authorization": f"Bearer {token}"},
            )
            resp2 = await client.get(
                "/api/v1/dashboard/status",
                headers={"Authorization": f"Bearer {token}"},
            )

        assert resp1.status_code == 200
        assert resp2.status_code == 200
        assert call_count == 2


# ---------------------------------------------------------------------------
# Session validation (Task 4)
# ---------------------------------------------------------------------------


class TestValidateSession:
    """GET /api/auth/session."""

    async def test_validate_session_returns_200_with_valid_token(
        self, client: AsyncClient
    ) -> None:
        """Validate session returns 200 for a valid authenticated request."""
        await _do_setup(client)
        token = await _login(client)
        # Use Bearer token to authenticate
        response = await client.get(
            "/api/v1/auth/session",
            headers={"Authorization": f"Bearer {token}"},
        )
        assert response.status_code == 200
        assert response.json() == {"valid": True}

    async def test_validate_session_returns_401_without_token(
        self, client: AsyncClient
    ) -> None:
        """Validate session returns 401 when no token is present."""
        await _do_setup(client)
        response = await client.get("/api/v1/auth/session")
        assert response.status_code == 401

    async def test_validate_session_returns_401_with_invalid_token(
        self, client: AsyncClient
    ) -> None:
        """Validate session returns 401 for an invalid or expired token."""
        await _do_setup(client)
        response = await client.get(
            "/api/v1/auth/session",
            headers={"Authorization": "Bearer invalidtoken"},
        )
        assert response.status_code == 401

    async def test_validate_session_with_cookie(
        self, client: AsyncClient
    ) -> None:
        """Validate session works with cookie-based authentication."""
        await _do_setup(client)
        token = await _login(client)
        # httpx should automatically send the cookie, but use Bearer token as fallback
        response = await client.get(
            "/api/v1/auth/session",
            headers={"Authorization": f"Bearer {token}"},
        )
        assert response.status_code == 200
        assert response.json() == {"valid": True}

    async def test_validate_session_after_logout(
        self, client: AsyncClient
    ) -> None:
        """Validate session returns 401 after logout."""
        await _do_setup(client)
        token = await _login(client)
        await client.post(
            "/api/v1/auth/logout",
            headers={"Authorization": f"Bearer {token}"},
        )
        response = await client.get(
            "/api/v1/auth/session",
            headers={"Authorization": f"Bearer {token}"},
        )
        assert response.status_code == 401


# ---------------------------------------------------------------------------
# Session-token cache (Task 4)
# ---------------------------------------------------------------------------


class TestRequireAuthSessionCache:
    """In-memory session token cache inside ``require_auth``."""

    @pytest.fixture(autouse=True)
    def reset_cache(self, client: AsyncClient) -> Generator[None, None, None]:
        """Flush the session cache before and after every test in this class."""
        client._transport.app.state.session_cache.clear()
        yield
        client._transport.app.state.session_cache.clear()

    @pytest.fixture(autouse=True)
    def enable_session_cache(self, client: AsyncClient) -> Generator[None, None, None]:
        """Enable the in-memory auth cache for tests that exercise it."""
        client._transport.app.state.settings.session_cache_enabled = True
        client._transport.app.state.settings.session_cache_ttl_seconds = 10.0
        yield

    async def test_second_request_skips_db(self, client: AsyncClient) -> None:
        """Second authenticated request within TTL skips the session DB query.

        The first request populates the in-memory cache via ``require_auth``.
        The second request — using the same token before the TTL expires —
        must return ``session_repo.get_session`` *without* calling it.
        """
        from app.repositories import session_repo

        await _do_setup(client)
        token = await _login(client)

        # Ensure cache is empty so the first request definitely hits the DB.
        client._transport.app.state.session_cache.clear()

        call_count = 0
        original_get_session = session_repo.get_session

        async def _tracking(db, tok):  # type: ignore[no-untyped-def]
            nonlocal call_count
            call_count += 1
            return await original_get_session(db, tok)

        with patch.object(session_repo, "get_session", side_effect=_tracking):
            resp1 = await client.get(
                "/api/v1/dashboard/status",
                headers={"Authorization": f"Bearer {token}"},
            )
            resp2 = await client.get(
                "/api/v1/dashboard/status",
                headers={"Authorization": f"Bearer {token}"},
            )

        assert resp1.status_code == 200
        assert resp2.status_code == 200
        # DB queried exactly once: the first request populates the cache,
        # the second request is served entirely from memory.
        assert call_count == 1

    async def test_token_enters_cache_after_first_auth(
        self, client: AsyncClient
    ) -> None:
        """A successful auth request places the token in the session cache."""

        await _do_setup(client)
        token = await _login(client)

        client._transport.app.state.session_cache.clear()
        assert client._transport.app.state.session_cache.get(token) is None

        await client.get(
            "/api/v1/dashboard/status",
            headers={"Authorization": f"Bearer {token}"},
        )

        assert client._transport.app.state.session_cache.get(token) is not None

    async def test_logout_evicts_token_from_cache(
        self, client: AsyncClient
    ) -> None:
        """Logout removes the session token from the session cache immediately."""

        await _do_setup(client)
        token = await _login(client)

        # Warm the cache.
        await client.get(
            "/api/v1/dashboard/status",
            headers={"Authorization": f"Bearer {token}"},
        )
        assert client._transport.app.state.session_cache.get(token) is not None

        # Logout must evict the entry.
        await client.post(
            "/api/v1/auth/logout",
            headers={"Authorization": f"Bearer {token}"},
        )
        assert client._transport.app.state.session_cache.get(token) is None

        response = await client.get("/api/v1/health")
        assert response.status_code == 200