"""Shared Playwright auth helper (phase 16).

``login`` drives the REAL form login on /login.html (fill → submit →
redirect) so every story that needs the admin does exactly what a human
would — no cookie surgery. ``password=None`` uses the shared E2E admin
password (success path); pass a wrong value to drive the error state
(no redirect, ``#login-error`` role=alert visible, still anonymous).
"""
from __future__ import annotations

from playwright.sync_api import Page, expect

from e2e.conftest import ADMIN_PASSWORD  # noqa: F401  (re-exported for tests)

DEFAULT_NEXT = "/sources.html"


def login(page: Page, app_url: str, password: str | None = None, next: str | None = None) -> None:
    """Perform the real form login and wait for its outcome.

    * correct password (or ``password=None`` → the shared admin password)
      → redirects to ``next`` (default ``/sources.html``);
    * wrong password → ``#login-error`` (role=alert) is visible, the URL
      never changes, and the visitor is still anonymous.
    """
    attempt = ADMIN_PASSWORD if password is None else password
    url = f"{app_url}/login.html"
    if next is not None:
        url += f"?next={next}"
    page.goto(url)
    expect(page.locator("#login-password")).to_be_visible()
    page.fill("#login-password", attempt)
    page.click("#login-form button[type=submit]")
    if attempt != ADMIN_PASSWORD:
        expect(page.locator("#login-error")).to_be_visible(timeout=15_000)
        expect(page).to_have_url(url)  # no redirect on failure
        return
    expect(page).to_have_url(app_url + (next or DEFAULT_NEXT), timeout=30_000)