#!/usr/bin/env python3
"""Shared intercept / title / extractability heuristics. No secrets."""
from __future__ import annotations

import re
from urllib.parse import urlparse

BLOCK_TITLE = re.compile(
    r"(just a moment|attention required|access denied|access to this page has been denied|"
    r"verify you are human|are you a human|robot check|pardon our interruption|"
    r"please enable cookies|security check|sorry.? something went wrong|"
    r"click the button below|continue shopping|unusual traffic)",
    re.I,
)


def _blob(*parts: str) -> str:
    return "\n".join(p or "" for p in parts).lower()


def classify_intercept(
    *,
    http_status: int | None,
    final_url: str,
    start_url: str,
    title: str,
    text: str,
    html_head: str,
    headers: dict | None = None,
    error: str | None = None,
    redirect_hops: int = 0,
) -> str:
    headers = {str(k).lower(): str(v) for k, v in (headers or {}).items()}
    blob = _blob(title, text, html_head, " ".join(headers.values()), error or "")
    hdrs = " ".join(f"{k}:{v}" for k, v in headers.items())

    if BLOCK_TITLE.search(title or "") or "cf-challenge" in blob or "cf-turnstile" in blob:
        if "cloudflare" in blob or "cf-ray" in hdrs.lower() or "cf-mitigated" in hdrs.lower():
            return "cloudflare"
    if "cloudflare" in blob and ("just a moment" in blob or "attention required" in blob):
        return "cloudflare"
    if "cf-ray" in hdrs.lower() and (http_status in (403, 503, 429) or "just a moment" in blob):
        return "cloudflare"

    if any(x in blob for x in ("recaptcha", "hcaptcha", "cf-turnstile", "geetest", "验证码")):
        if any(x in blob for x in ("captcha", "turnstile", "verify you are", "人机验证", "安全验证")):
            return "captcha"
    if re.search(r"\bcaptcha\b", blob) and any(
        x in blob for x in ("robot", "verify", "human", "enter the characters", "opfcaptcha")
    ):
        return "captcha"

    if any(
        x in blob
        for x in (
            "opfcaptcha",
            "validatecaptcha",
            "amazon.com/errors",
            "click the button below to continue shopping",
            "datadome",
            "captcha-delivery",
            "akamai",
            "access denied",
            "request blocked",
            "robot check",
        )
    ):
        return "waf"
    if http_status in (403, 429) and any(x in blob for x in ("waf", "forbidden", "blocked", "denied")):
        return "waf"
    if http_status == 403 and ("reddit" in (start_url or "") or "www.reddit.com" in (final_url or "")):
        return "waf"

    if any(x in blob for x in ("paywall", "subscribe to continue", "become a member to", "metered paywall")):
        return "paywall"

    start_host = (urlparse(start_url).hostname or "").lower().removeprefix("www.")
    final_host = (urlparse(final_url or start_url).hostname or "").lower().removeprefix("www.")
    path = (urlparse(final_url or "").path or "").lower()
    loginish = any(x in path for x in ("/login", "/signin", "/checkpoint", "/account/login", "/passport"))
    if loginish and (http_status in (200, 302, 301, 303, 307, 308) or redirect_hops):
        # login wall after hop is still a redirect-class block for our matrix
        return "redirect"
    if start_host and final_host and start_host != final_host:
        # stay on same brand (bbc.com -> bbc.co.uk etc.) is not always a block
        if not (start_host in final_host or final_host in start_host):
            return "redirect"
    if http_status in (301, 302, 303, 307, 308) and redirect_hops >= 1:
        return "redirect"

    if error and any(x in error.lower() for x in ("timed out", "timeout", "timedout")):
        return "empty"
    if not http_status or http_status == 0:
        return "empty"
    if http_status >= 400:
        # unclassified error page with no vendor fingerprint
        if len((text or "").strip()) < 80:
            return "empty"
        return "waf" if http_status in (401, 403, 406, 429, 451, 503) else "empty"

    text_len = len((text or "").strip())
    if text_len < 80:
        return "empty"
    return "none"


def title_ok(title: str, needles: list[str], intercept: str) -> bool:
    if intercept in {"cloudflare", "waf", "captcha"}:
        return False
    t = (title or "").lower()
    if not t.strip():
        return False
    if BLOCK_TITLE.search(title or ""):
        return False
    for n in needles or []:
        if n.lower() in t:
            return True
    # X/Twitter homepage often titles exactly "X"
    if t.strip() in {"x", "x.com"}:
        return True
    return False


def extractable(intercept: str, text_len: int, title_is_ok: bool) -> bool:
    if intercept != "none":
        return False
    if text_len >= 200:
        return True
    if text_len >= 80 and title_is_ok:
        return True
    return False