"""Undetected Playwright launcher for FCC / USAC / BDC portals.

All automated filing handlers (RMD, CPNI, Form 499-A, BDC) go through this
helper instead of importing ``playwright`` directly. We prefer ``patchright``
(a drop-in Playwright replacement that patches ``navigator.webdriver``, CDP
leakage, runtime-enable fingerprints, and the ``--disable-blink-features=
AutomationControlled`` artifact) and fall back to vanilla Playwright with
the same stealth init scripts we use in ``scripts/formation/base.py`` if
patchright is not installed.

State formation portals that sit behind Incapsula/Akamai (Nevada, Delaware,
etc.) should also use this helper — see ``docs/state-automation-status.md``
for the list.

Optional residential proxy support: set ``UNDETECTED_PROXY_URL`` in the
environment (e.g. ``http://user:pass@proxy.example.com:8080``) and pass
``use_proxy=True`` when launching.
"""

from __future__ import annotations

import logging
import os
import random
from contextlib import asynccontextmanager
from typing import TYPE_CHECKING, AsyncIterator

if TYPE_CHECKING:
    from playwright.async_api import Browser, BrowserContext, Page, Playwright

logger = logging.getLogger(__name__)


# Prefer patchright; fall back to playwright with manual stealth patches.
_USING_PATCHRIGHT = False
try:
    from patchright.async_api import async_playwright  # type: ignore

    _USING_PATCHRIGHT = True
    logger.info("undetected_browser: using patchright")
except ImportError:
    from playwright.async_api import async_playwright  # type: ignore

    logger.warning(
        "undetected_browser: patchright not installed — falling back to "
        "vanilla playwright with home-grown stealth patches. Install with "
        "`pip install patchright` and run `patchright install chromium` "
        "for best results against bot-detection-heavy portals."
    )


# Common modern Chrome UAs. We rotate between a handful so that a burst of
# concurrent submissions doesn't all look like the same client.
_USER_AGENTS = [
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 "
    "(KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36",
    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 "
    "(KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36",
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 "
    "(KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36",
]

# Common viewports; mildly jittered per-launch to vary fingerprint.
_VIEWPORTS = [
    {"width": 1280, "height": 900},
    {"width": 1440, "height": 900},
    {"width": 1536, "height": 864},
    {"width": 1920, "height": 1080},
]

# Init script run on every page — only used on the vanilla-playwright path;
# patchright handles all of these patches (and many more) internally.
_STEALTH_INIT_SCRIPT = """
Object.defineProperty(navigator, 'webdriver', { get: () => undefined });
Object.defineProperty(navigator, 'plugins', {
    get: () => [1, 2, 3, 4, 5].map(() => ({ name: 'Chrome PDF Plugin' })),
});
Object.defineProperty(navigator, 'languages', { get: () => ['en-US', 'en'] });
window.chrome = { runtime: {} };
const originalQuery = window.navigator.permissions && window.navigator.permissions.query;
if (originalQuery) {
    window.navigator.permissions.query = (parameters) =>
        parameters.name === 'notifications'
            ? Promise.resolve({ state: Notification.permission })
            : originalQuery(parameters);
}
"""


def _proxy_config() -> dict | None:
    """Read UNDETECTED_PROXY_URL and turn it into a Playwright proxy dict."""
    url = os.environ.get("UNDETECTED_PROXY_URL", "").strip()
    if not url:
        return None

    # Playwright's proxy dict supports: server, username, password, bypass
    from urllib.parse import urlparse

    parsed = urlparse(url)
    server = f"{parsed.scheme}://{parsed.hostname}"
    if parsed.port:
        server += f":{parsed.port}"

    cfg: dict = {"server": server}
    if parsed.username:
        cfg["username"] = parsed.username
    if parsed.password:
        cfg["password"] = parsed.password
    return cfg


async def launch_context(
    playwright: "Playwright",
    *,
    headless: bool = True,
    use_proxy: bool = False,
    timezone_id: str = "America/New_York",
    locale: str = "en-US",
    storage_state: str | None = None,
) -> "tuple[Browser, BrowserContext]":
    """Launch a Chromium browser + context with stealth settings.

    Returns ``(browser, context)`` — caller is responsible for closing both
    (prefer the :func:`undetected_browser` context manager instead).
    """

    launch_args = [
        "--no-sandbox",
        "--disable-setuid-sandbox",
        "--disable-dev-shm-usage",
    ]
    # On the vanilla-playwright path we add the extra flag that hides the
    # AutomationControlled fingerprint. Patchright already does this (and
    # adding the flag with patchright is harmless but redundant).
    if not _USING_PATCHRIGHT:
        launch_args.append("--disable-blink-features=AutomationControlled")

    browser = await playwright.chromium.launch(
        headless=headless,
        args=launch_args,
    )

    context_kwargs: dict = {
        "viewport": random.choice(_VIEWPORTS),
        "user_agent": random.choice(_USER_AGENTS),
        "locale": locale,
        "timezone_id": timezone_id,
        "java_script_enabled": True,
    }
    if use_proxy:
        proxy = _proxy_config()
        if proxy:
            context_kwargs["proxy"] = proxy
        else:
            logger.warning(
                "undetected_browser: use_proxy=True but UNDETECTED_PROXY_URL is unset"
            )
    if storage_state:
        context_kwargs["storage_state"] = storage_state

    context = await browser.new_context(**context_kwargs)

    if not _USING_PATCHRIGHT:
        await context.add_init_script(_STEALTH_INIT_SCRIPT)

    return browser, context


@asynccontextmanager
async def undetected_browser(
    *,
    headless: bool = True,
    use_proxy: bool = False,
    timezone_id: str = "America/New_York",
    locale: str = "en-US",
    storage_state: str | None = None,
) -> AsyncIterator["tuple[BrowserContext, Page]"]:
    """Async context manager yielding a (context, page) pair.

    Example::

        async with undetected_browser(headless=False) as (ctx, page):
            await page.goto("https://apps.fcc.gov/rmd/")
            ...
    """
    async with async_playwright() as pw:
        browser, context = await launch_context(
            pw,
            headless=headless,
            use_proxy=use_proxy,
            timezone_id=timezone_id,
            locale=locale,
            storage_state=storage_state,
        )
        try:
            page = await context.new_page()
            yield context, page
        finally:
            await context.close()
            await browser.close()


# ─── Human-like interaction helpers (lifted from scripts/formation/base.py) ──

async def human_delay(min_s: float = 1.0, max_s: float = 3.0) -> None:
    """Random delay to appear human. Mirrors the formation base helper."""
    import asyncio

    await asyncio.sleep(random.uniform(min_s, max_s))


async def type_slowly(page: "Page", selector: str, text: str, delay_ms: int = 50) -> None:
    """Type text character-by-character with jitter."""
    await page.click(selector)
    for char in text:
        await page.type(selector, char, delay=delay_ms + random.randint(0, 30))


def is_using_patchright() -> bool:
    """Return True if patchright is the active backend."""
    return _USING_PATCHRIGHT