"""Real-browser tests: Playwright drives Chromium against Django's live server.

Needs the browser once per machine: `uv run playwright install chromium`. Without it these
tests skip, so the rest of the suite still runs anywhere.
"""

import os
from pathlib import Path

import pytest
from django.conf import settings

# Playwright's sync API runs an event loop; the ORM calls in fixtures are still synchronous.
os.environ.setdefault("DJANGO_ALLOW_ASYNC_UNSAFE", "true")

from playwright.sync_api import Error as PlaywrightError  # noqa: E402
from playwright.sync_api import sync_playwright  # noqa: E402

AXE = (Path(__file__).parent.parent / "vendor" / "axe.min.js").read_text()


@pytest.fixture(scope="session")
def browser():
    with sync_playwright() as p:
        try:
            browser = p.chromium.launch()
        except PlaywrightError as exc:
            pytest.skip(f"Chromium isn't installed (uv run playwright install chromium): {exc}")
        yield browser
        browser.close()


@pytest.fixture
def page(browser, live_server):
    """A fresh page. `page.problems` collects script errors and CSP violations.

    The CSP is enforced, except on `axe_page`, where axe has to be injected inline.
    """
    context = browser.new_context(base_url=live_server.url)
    page = context.new_page()
    page.problems = []
    page.on("pageerror", lambda e: page.problems.append(f"script error: {e}"))
    page.on(
        "console",
        lambda m: (
            page.problems.append(f"console: {m.text}")
            if m.type == "error" and "Content Security Policy" in m.text
            else None
        ),
    )
    yield page
    context.close()


@pytest.fixture
def axe_page(browser, live_server):
    context = browser.new_context(base_url=live_server.url, bypass_csp=True)
    page = context.new_page()
    yield page
    context.close()


def share_session(client, page, live_server, user):
    client.force_login(user)
    page.context.add_cookies(
        [
            {
                "name": settings.SESSION_COOKIE_NAME,
                "value": client.cookies[settings.SESSION_COOKIE_NAME].value,
                "url": live_server.url,
            }
        ]
    )


@pytest.fixture
def sign_in(client, page, live_server):
    """Sign the browser in as `user` by sharing a test-client session."""

    def as_user(user):
        share_session(client, page, live_server, user)

    return as_user


def axe_violations(page, scheme: str) -> list[str]:
    """Run axe on the current page with WCAG 2.1 A and AA rules."""
    page.emulate_media(color_scheme=scheme)
    page.add_script_tag(content=AXE)
    result = page.evaluate(
        """async () => {
            const r = await axe.run(document, {
                runOnly: {type: "tag", values: ["wcag2a", "wcag2aa", "wcag21a", "wcag21aa"]},
            });
            return r.violations.map(v =>
                `${v.id} (${v.impact}): ${v.help} — ${v.nodes.slice(0, 3)
                    .map(n => n.target.join(" ")).join(", ")}`);
        }"""
    )
    return result