from __future__ import annotations

from dataclasses import dataclass
from typing import Iterable

import httpx

# High-traffic destinations that often reveal proxy bans quickly.
POPULAR_SITES: tuple[tuple[str, str], ...] = (
    ("Google", "https://www.google.com/generate_204"),
    ("YouTube", "https://www.youtube.com/"),
    ("Facebook", "https://www.facebook.com/"),
    ("Instagram", "https://www.instagram.com/"),
    ("X", "https://x.com/"),
    ("Reddit", "https://www.reddit.com/"),
    ("Wikipedia", "https://www.wikipedia.org/"),
    ("Amazon", "https://www.amazon.com/"),
    ("Netflix", "https://www.netflix.com/"),
    ("GitHub", "https://github.com/"),
    ("Cloudflare", "https://www.cloudflare.com/"),
    ("Microsoft", "https://www.microsoft.com/"),
    ("TikTok", "https://www.tiktok.com/"),
    ("BBC", "https://www.bbc.com/"),
    ("DuckDuckGo", "https://duckduckgo.com/"),
)

_BANNED_STATUS_CODES = {401, 403, 407, 418, 429, 451}
_BANNED_TEXT_HINTS = (
    "access denied",
    "forbidden",
    "temporarily blocked",
    "request blocked",
    "unusual traffic",
    "captcha",
    "challenge required",
)


@dataclass(frozen=True)
class BanTestResult:
    site: str
    url: str
    status: str  # ok | banned | error
    code: int | None
    detail: str


def _looks_banned_body(body: str) -> bool:
    t = (body or "").lower()
    return any(h in t for h in _BANNED_TEXT_HINTS)


def _test_one(proxy_url: str, site: str, url: str, timeout_seconds: float) -> BanTestResult:
    timeout = httpx.Timeout(timeout_seconds, connect=min(8.0, timeout_seconds))
    try:
        with httpx.Client(
            proxy=proxy_url,
            timeout=timeout,
            verify=False,
            follow_redirects=True,
            headers={"User-Agent": "Mozilla/5.0"},
        ) as c:
            r = c.get(url)
            body = r.text[:1800] if r.text else ""
            if r.status_code in _BANNED_STATUS_CODES or _looks_banned_body(body):
                return BanTestResult(site, url, "banned", r.status_code, f"HTTP {r.status_code}")
            if 200 <= r.status_code < 400:
                return BanTestResult(site, url, "ok", r.status_code, f"HTTP {r.status_code}")
            return BanTestResult(site, url, "error", r.status_code, f"HTTP {r.status_code}")
    except Exception as e:
        return BanTestResult(site, url, "error", None, f"{type(e).__name__}: {e}")


def run_ban_tests(
    proxy_url: str,
    timeout_seconds: float = 12.0,
    sites: Iterable[tuple[str, str]] = POPULAR_SITES,
) -> list[BanTestResult]:
    out: list[BanTestResult] = []
    for site, url in sites:
        out.append(_test_one(proxy_url, site, url, timeout_seconds))
    return out


def test_single_site(
    proxy_url: str,
    site: str,
    url: str,
    timeout_seconds: float = 10.0,
) -> BanTestResult:
    """Probe one URL through the proxy. Used by pre-flight checks."""
    return _test_one(proxy_url, site, url, timeout_seconds)