"""
Scout-Logik: Domain scannen, Links extrahieren, via OpenRouter Publikations-URL identifizieren.
Mit Stealth und HTTP/2-Fallback gegen extreme Bot-Detection.
"""
import json
import re
from typing import Any
from urllib.parse import urlparse

import httpx
from playwright.async_api import async_playwright
from playwright_stealth import Stealth

# OpenRouter Base-URL und Modell
OPENROUTER_BASE = "https://openrouter.ai/api/v1"
DEFAULT_MODEL = "google/gemini-flash-1.5-8b"

# Browser-Konfiguration gegen Bot-Detection (z. B. McKinsey) und HTTP/2-Fehler
USER_AGENT = (
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 "
    "(KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36"
)
EXTRA_HEADERS = {
    "Accept-Language": "de-DE,de;q=0.9,en-US;q=0.8,en;q=0.7",
    "Referer": "https://www.google.com/",
}
VIEWPORT = {"width": 1920, "height": 1080}
GOTO_TIMEOUT = 60_000  # ms


def _normalize_domain(domain: str) -> str:
    """Extrahiert die reine Domain (Host) ohne Schema und Pfad."""
    s = domain.strip()
    if s.startswith("http://"):
        s = s[7:]
    elif s.startswith("https://"):
        s = s[8:]
    if "/" in s:
        s = s.split("/", 1)[0]
    return s.lower() or domain


def _url_with_www(domain: str) -> str:
    """Immer https://www.{domain} für einheitlichen Aufruf."""
    host = _normalize_domain(domain)
    return f"https://www.{host}"


def _url_without_www(domain: str) -> str:
    """https://{domain} für Fallback ohne www."""
    host = _normalize_domain(domain)
    return f"https://{host}"


async def _fetch_links_impl(domain: str, disable_http2: bool = False) -> list[dict[str, str]]:
    """
    Interne Implementierung: Browser starten, Stealth anwenden, Zielseite laden, Links extrahieren.
    Bei disable_http2=True wird Chromium mit args=['--disable-http2'] gestartet (Fallback bei ERR_HTTP2_PROTOCOL_ERROR).
    """
    url_primary = _url_with_www(domain)
    url_insights = f"{url_primary.rstrip('/')}/featured-insights"  # Direkt zur Insights-Seite (z. B. McKinsey)
    url_fallback = _url_without_www(domain)
    links: list[dict[str, str]] = []

    launch_options: dict[str, Any] = {"headless": True}
    if disable_http2:
        launch_options["args"] = ["--disable-http2"]

    async with async_playwright() as p:
        browser = await p.chromium.launch(**launch_options)
        try:
            # Kontext: aktueller User-Agent, JavaScript an, Headers, Viewport (Bot-Detection umgehen)
            context = await browser.new_context(
                user_agent=USER_AGENT,
                extra_http_headers=EXTRA_HEADERS,
                viewport=VIEWPORT,
                java_script_enabled=True,
            )
            # Stealth auf Kontext anwenden (API 2.x: apply_stealth_async(context))
            await Stealth().apply_stealth_async(context)
            page = await context.new_page()

            # Versuch 1: Direkt zur Zielseite (z. B. https://www.mckinsey.com/featured-insights)
            try:
                await page.goto(
                    url_insights,
                    wait_until="networkidle",
                    timeout=GOTO_TIMEOUT,
                )
            except Exception:
                # Versuch 2: Startseite mit www
                try:
                    await page.goto(
                        url_primary,
                        wait_until="networkidle",
                        timeout=GOTO_TIMEOUT,
                    )
                except Exception:
                    # Versuch 3: ohne www
                    try:
                        await page.goto(
                            url_fallback,
                            wait_until="networkidle",
                            timeout=GOTO_TIMEOUT,
                        )
                    except Exception:
                        # Versuch 4: domcontentloaded als letzter Fallback
                        try:
                            await page.goto(
                                url_primary,
                                wait_until="domcontentloaded",
                                timeout=30_000,
                            )
                        except Exception:
                            await page.goto(
                                url_fallback,
                                wait_until="domcontentloaded",
                                timeout=30_000,
                            )

            # Alle <a href="..."> auslesen
            links = await page.evaluate(
                """() => {
                const anchors = document.querySelectorAll('a[href]');
                return Array.from(anchors).map(a => ({
                    text: (a.textContent || '').trim().slice(0, 200),
                    href: a.getAttribute('href') || ''
                })).filter(x => x.href);
            }"""
            )
            await context.close()
        finally:
            await browser.close()

    return links


async def _fetch_links_with_playwright(domain: str) -> list[dict[str, str]]:
    """
    Lädt die Domain mit Playwright (Stealth, Kontext gegen Bot-Detection), extrahiert <a>-Tags.
    Bei ERR_HTTP2_PROTOCOL_ERROR: erneuter Versuch mit --disable-http2.
    """
    try:
        return await _fetch_links_impl(domain, disable_http2=False)
    except Exception as e:
        err_msg = str(e)
        if "ERR_HTTP2_PROTOCOL_ERROR" in err_msg or "net::ERR_" in err_msg:
            return await _fetch_links_impl(domain, disable_http2=True)
        raise


def _make_absolute(href: str, base_url: str) -> str:
    """Macht relative URLs absolut (einfache Heuristik)."""
    if not href or href.startswith("#"):
        return ""
    if href.startswith("http://") or href.startswith("https://"):
        return href
    base = base_url.rstrip("/")
    if href.startswith("/"):
        parsed = urlparse(base)
        return f"{parsed.scheme}://{parsed.netloc}{href}"
    return f"{base}/{href}"


async def _ask_openrouter(api_key: str, links: list[dict[str, str]], domain: str) -> str | None:
    """
    Sendet die Link-Liste an OpenRouter und fordert die beste Publikations-URL an.
    Erwartet Antwort im Format: {"url": "..."} – unverändert.
    """
    base_url = _url_with_www(domain)
    prompt = (
        "Analysiere diese Links einer Unternehmensberatung. "
        "Welcher Link führt zur Seite mit Reports, Insights oder Fachartikeln? "
        "Antworte NUR mit der absoluten URL im JSON-Format: {'url': '...'}"
    )
    links_text = "\n".join(
        f"- {l.get('text', '')} -> {_make_absolute(l.get('href', ''), base_url)}"
        for l in links[:80]  # Begrenzen, um Token-Limit zu schonen
    )
    user_content = f"Links von {domain}:\n{links_text}"

    async with httpx.AsyncClient(timeout=30.0) as client:
        resp = await client.post(
            f"{OPENROUTER_BASE}/chat/completions",
            headers={
                "Authorization": f"Bearer {api_key}",
                "Content-Type": "application/json",
                "HTTP-Referer": base_url,
            },
            json={
                "model": DEFAULT_MODEL,
                "messages": [
                    {"role": "system", "content": prompt},
                    {"role": "user", "content": user_content},
                ],
                "max_tokens": 256,
            },
        )
        resp.raise_for_status()
        data = resp.json()
        choice = (data.get("choices") or [None])[0]
        if not choice:
            return None
        content = (choice.get("message") or {}).get("content") or ""
        if not content.strip():
            return None

    # JSON aus Antwort extrahieren (falls von Markdown umgeben)
    content = content.strip()
    json_match = re.search(r"\{[^{}]*\"url\"[^{}]*\}", content)
    if json_match:
        try:
            obj = json.loads(json_match.group())
            return (obj.get("url") or "").strip() or None
        except json.JSONDecodeError:
            pass
    try:
        obj = json.loads(content)
        return (obj.get("url") or "").strip() or None
    except json.JSONDecodeError:
        return None


async def get_publication_url(domain: str, *, api_key: str | None = None) -> dict[str, Any]:
    """
    Hauptfunktion: Domain scannen, Links an OpenRouter senden,
    gefundene Publikations-URL zurückgeben.
    """
    import os
    key = api_key or os.getenv("OPENROUTER_API_KEY")
    if not key:
        return {"url": None, "error": "OPENROUTER_API_KEY nicht gesetzt"}

    try:
        links = await _fetch_links_with_playwright(domain)
    except Exception as e:
        return {"url": None, "error": f"Playwright/Scrape-Fehler: {e!s}"}

    if not links:
        return {"url": None, "error": "Keine Links auf der Seite gefunden"}

    try:
        url = await _ask_openrouter(key, links, domain)
        return {"url": url, "error": None}
    except Exception as e:
        return {"url": None, "error": f"OpenRouter-Fehler: {e!s}"}