"""
research.py — Ricerca web multi-URL con ARL (Adaptive Research Loop).

Endpoint:
  POST /api/web/research  — ricerca multi-round con raffinamento automatico della query

Flusso (V5 — ARL + parallel multi-query + GF-7 smart retry):
  1. Round 0: _gen_alt_queries() → 3 query parallele → corpus unificato (GAP-RESEARCH-PARALLEL)
  2. Calcola goal_coverage: frazione di token-goal presenti nel corpus
  3. Se coverage >= MIN_COVERAGE → esci
  4. Se coverage < MIN_COVERAGE → _refine_query() → round successivo (max MAX_ROUNDS)
  5. GF-7: se new_urls vuoto (tutti già visitati) O ok_pages vuoto → cambia query strategy
     invece di uscire: prova variante lessicale non ancora tentata, poi esci solo se esaurite
  6. Sintesi finale Groq (se key disponibile)

Budget (iPhone free tier):
  - Round 0: 3 query × N URL = max 3×6=18 fetch in parallelo (≈ stessa latenza di 6 sequenziali)
  - Round 1+: max 4 round × 6 URL = max 24 fetch totali
  - Hard timeout: MIN_COVERAGE=0.70 o page budget esaurito
"""
import asyncio, os, re, logging, time
import httpx
from fastapi import APIRouter, HTTPException, Request
from pydantic import BaseModel

router  = APIRouter(prefix="/api/web", tags=["web-research"])
_logger = logging.getLogger("research")

_UA        = "Mozilla/5.0 (compatible; AgenteAI/3.0)"
_MAX_SRC   = 8          # max URL totali per ricerca
_MAX_ROUNDS = 5         # QF-1: 3→5 — più coverage per task complessi
_MAX_URLS_PER_ROUND = 6 # QF-1: 4→6 URL per round — maggiore coverage fonti
_MIN_COVERAGE = 0.70    # token goal coverage per uscita anticipata
_TIMEOUT_S    = 35.0    # QF-1: 20→35s timeout ARL — supporta 5 round × 6 URL


class ResearchRequest(BaseModel):
    topic:      str
    depth:      int  = 4      # number of sources per round
    lang:       str  = "it"   # language for results
    synthesize: bool = True   # use LLM to synthesize if key available


# ─── ARL helpers ─────────────────────────────────────────────────────────────

_STOP_WORDS = {
    "the","and","for","with","that","this","from","into","have","are","was","were",
    "che","del","della","per","con","una","uno","gli","dei","nel","nelle","alla",
    "sulle","degli","sono","come","quando","dove","anche","quindi","essere",
}

def _tokenize(txt: str) -> set[str]:
    return {t for t in re.split(r'\W+', txt.lower()) if len(t) > 3 and t not in _STOP_WORDS}

def _goal_coverage(goal: str, corpus: str) -> float:
    """Calcola la fraction di token-goal presenti nel corpus (ARL coverage check)."""
    goal_toks = _tokenize(goal)
    if not goal_toks:
        return 1.0
    found_toks = _tokenize(corpus)
    return sum(1 for t in goal_toks if t in found_toks) / len(goal_toks)

def _refine_query(goal: str, corpus: str) -> str | None:
    """Genera query di refinement basata sui token-goal mancanti nel corpus.
    Zero LLM — solo analisi lessicale.
    """
    goal_list  = [t for t in re.split(r'\W+', goal.lower()) if len(t) > 3 and t not in _STOP_WORDS]
    found_toks = _tokenize(corpus)
    missing    = [t for t in goal_list if t not in found_toks]
    if not missing:
        return None
    # Suffix: ultimi 2 token del goal NON già nei missing (evita duplicati)
    missing_set = set(missing)
    raw_suffix  = [w for w in goal.strip().split()[-2:]
                   if w.lower().rstrip("?!.,;:") not in missing_set]
    raw_query   = f"{' '.join(missing[:3])} {' '.join(raw_suffix)}".strip()
    # Dedup mantenendo l'ordine (evita "finanziamento finanziamento")
    seen: set[str] = set()
    parts = []
    for w in raw_query.split():
        k = w.lower()
        if k not in seen:
            seen.add(k)
            parts.append(w)
    return " ".join(parts) if parts else None


# U1: mappatura IT→EN per variante inglese nelle query italiane.
# ~30 termini tecnici comuni; nomi propri (React, Vue, Docker…) invariati.
_IT_EN_MAP: dict[str, str] = {
    'autenticazione': 'authentication', 'accesso': 'login', 'registrazione': 'registration',
    'database': 'database', 'applicazione': 'application', 'componente': 'component',
    'pagina': 'page', 'schermata': 'screen', 'utente': 'user', 'errore': 'error',
    'configurazione': 'configuration', 'installazione': 'installation',
    'distribuzione': 'deployment', 'sviluppo': 'development',
    'funzione': 'function', 'classe': 'class', 'metodo': 'method',
    'variabile': 'variable', 'importazione': 'import', 'modulo': 'module',
    'libreria': 'library', 'integrazione': 'integration', 'servizio': 'service',
    'richiesta': 'request', 'risposta': 'response', 'connessione': 'connection',
    'sicurezza': 'security', 'ottimizzazione': 'optimization',
    'creare': 'create', 'costruire': 'build', 'implementare': 'implement',
    'aggiungere': 'add', 'aggiornare': 'update', 'chiamata': 'call',
    'interfaccia': 'interface', 'progetto': 'project', 'struttura': 'structure',
}
# Indicatori lessicali italiani (articoli, preposizioni, verbi comuni)
_IT_INDICATORS: frozenset[str] = frozenset({
    'come', 'cosa', 'perché', 'quando', 'dove', 'quale', 'quali',
    'creare', 'fare', 'usare', 'avere', 'essere', 'per', 'con',
    'una', 'uno', 'del', 'della', 'degli', 'dal', 'dalla', 'degli',
})

def _is_italian(text: str) -> bool:
    """Rileva se il testo è principalmente italiano — euristica lessicale leggera."""
    toks = {w.lower() for w in re.split(r'\W+', text) if w}
    return len(toks & _IT_INDICATORS) >= 2

def _translate_it_en(goal: str) -> str:
    """Traduzione IT→EN zero-LLM: sostituisce termini tecnici mappati,
    rimuove articoli/preposizioni italiani senza corrispondente inglese."""
    _it_stopwords = {'il', 'lo', 'la', 'le', 'gli', 'i', 'un', "un'", 'uno', 'una',
                     'di', 'da', 'in', 'con', 'su', 'per', 'tra', 'fra', 'che', 'come'}
    parts = []
    for w in goal.split():
        clean = w.lower().strip("'!?.,;:")
        if clean in _it_stopwords:
            continue  # articoli/preposizioni → drop
        en = _IT_EN_MAP.get(clean)
        if en:
            parts.append(en)
        elif not re.match(r'^[a-z]+', clean) or len(w) > 2:
            parts.append(w)  # parola non-IT o nome proprio → mantieni
    return ' '.join(parts).strip()

def _gen_fallback_queries(goal: str, tried: set[str]) -> list[str]:
    """GF-7: genera varianti di query non ancora tentate quando new_urls/ok_pages è vuoto.

    Chiamata solo quando il loop si troverebbe ad uscire con 0 nuovi URL o 0 pagine
    leggibili — invece di arrendersi, prova angolazioni diverse:
      v1 — inversione ordine parole chiave (cerca complemento prima del soggetto)
      v2 — aggiunge "tutorial" / "guida" / "come" (disambigua intent informativo)
      v3 — singola keyword più specifica (narrow search su termine principale)

    Zero LLM. Restituisce solo varianti non già in `tried`.
    """
    words = [w for w in re.split(r'\W+', goal) if len(w) > 2 and w.lower() not in _STOP_WORDS]
    candidates: list[str] = []

    # v1 — inversione ultime/prime keyword
    if len(words) >= 3:
        v1 = " ".join(words[len(words)//2:] + words[:len(words)//2])
        candidates.append(v1)

    # v2 — intent informativo esplicito
    kw_core = " ".join(words[:4])
    for prefix in ("come funziona", "guida", "spiegazione"):
        v2 = f"{prefix} {kw_core}".strip()
        candidates.append(v2)
        break  # un solo prefisso

    # v3 — termine più specifico (seconda keyword, spesso più discriminante)
    if len(words) >= 2:
        v3 = words[1] if len(words[1]) > 4 else (words[0] if len(words[0]) > 4 else "")
        if v3:
            candidates.append(v3)

    # D8: v4 — inversione completa delle keyword (garantisce query diversa da _gen_alt_queries)
    if len(words) >= 3:
        v4 = ' '.join(reversed(words))
        if v4 not in set(candidates):
            candidates.append(v4)

    return [c for c in candidates if c and c.lower() not in tried][:3]  # era :2, ora :3 per v4


# ─── Search: usa pipeline web_search.py (Brave → Tavily → Wikipedia → HN) ────

async def _pipeline_search(query: str, n: int) -> list[dict]:
    """Usa la pipeline condivisa web_search.py — stessa logica di _run_direct_tools."""
    try:
        from tools.web_search import web_search as _ws
        result = await _ws(query, max_results=n)
        hits = result.get("results", [])
        if hits:
            return [{"url": h["url"], "title": h.get("title", "")} for h in hits if h.get("url")]
    except Exception as exc:
        _logger.debug("pipeline_search fallback: %s", exc)
    return []


async def _ddg_fallback_search(query: str, n: int) -> list[dict]:
    """Fallback DDG HTML parse quando nessuna chiave API è configurata."""
    try:
        _ddg_kl = "it-it" if _is_italian(query) else "en-us"  # B-GAP-D: locale EN-aware
        _ddg_al = "it-IT,it;q=0.9,en;q=0.8" if _ddg_kl == "it-it" else "en-US,en;q=0.9"
        async with httpx.AsyncClient(timeout=10, headers={"User-Agent": _UA, "Accept-Language": _ddg_al}) as c:
            r = await c.get("https://html.duckduckgo.com/html/", params={"q": query, "kl": _ddg_kl})
            if r.status_code != 200:
                return []
            html = r.text
            link_pattern  = re.compile(r'<a[^>]+class="result__url"[^>]*href="([^"]+)"[^>]*>([^<]*)</a>', re.DOTALL)
            title_pattern = re.compile(r'<a[^>]+class="result__a"[^>]*href="[^"]+"[^>]*>([^<]+)</a>', re.DOTALL)
            links  = link_pattern.findall(html)
            titles = [re.sub(r"\s+", " ", t).strip() for t in title_pattern.findall(html)]
            results = []
            for i, (url, _) in enumerate(links[:n]):
                if url.startswith("http"):
                    results.append({"url": url, "title": titles[i] if i < len(titles) else url})
            return results[:n]
    except Exception:
        return []


# ─── Page content extraction ──────────────────────────────────────────────────

async def _fetch_page(url: str, max_chars: int = 2000) -> dict:
    try:
        async with httpx.AsyncClient(timeout=10, follow_redirects=True, headers={"User-Agent": _UA}) as c:
            r = await c.get(url)
            if r.status_code != 200:
                return {"url": url, "ok": False, "error": f"HTTP {r.status_code}"}
            html = r.text
        try:
            import trafilatura
            text = trafilatura.extract(
                html, include_comments=False, include_tables=False,
                favor_recall=True, deduplicate=True,
            ) or ""
        except ImportError:
            text = re.sub(r"<[^>]+>", " ", html)
            text = re.sub(r"\s{2,}", " ", text).strip()
        noise = {"cookie","accept all cookies","privacy policy","terms of service","subscribe","follow us on"}
        lines = [l for l in text.split("\n") if len(l.strip()) > 4 and not any(n in l.lower() for n in noise)]
        text  = "\n".join(lines)
        title_m = re.search(r"<title[^>]*>([^<]+)</title>", html, re.IGNORECASE)
        title   = title_m.group(1).strip()[:120] if title_m else url
        return {"url": url, "title": title, "text": text[:max_chars], "ok": True}
    except Exception as e:
        return {"url": url, "ok": False, "error": str(e)[:100]}


# ─── LLM synthesis (Groq) ─────────────────────────────────────────────────────

async def _synthesize(topic: str, sources: list[dict]) -> str:
    groq_key = os.getenv("GROQ_API_KEY", "")
    if not groq_key:
        return ""
    context = "\n\n".join(
        f"[{i+1}] {s['title']}\n{s['text'][:800]}"
        for i, s in enumerate(sources) if s.get("ok") and s.get("text")
    )[:6000]
    try:
        async with httpx.AsyncClient(timeout=30) as c:
            r = await c.post(
                "https://api.groq.com/openai/v1/chat/completions",
                headers={"Authorization": f"Bearer {groq_key}", "Content-Type": "application/json"},
                json={
                    "model": "llama-3.1-8b-instant",
                    "max_tokens": 700,
                    "messages": [
                        {"role": "system", "content": "Sei un assistente che sintetizza informazioni web. Rispondi sempre in italiano. Sii conciso e preciso."},
                        {"role": "user", "content": (
                            f"Argomento: **{topic}**\n\n"
                            f"Fonti trovate:\n{context}\n\n"
                            "Sintetizza le informazioni principali in 3-5 punti chiave, citando le fonti [N]."
                        )},
                    ],
                },
            )
            if r.status_code == 200:
                _chs = r.json().get("choices") or []
                return (_chs[0].get("message", {}).get("content") or "") if _chs else ""
    except Exception as exc:
        _logger.debug("synthesis error: %s", exc)
    return ""


# ─── Main endpoint ────────────────────────────────────────────────────────────

@router.post("/research")
async def web_research(req: ResearchRequest, request: Request):
    # S-GAP23: X-Internal-Token guard — protegge consumi Groq API da abusi esterni.
    _internal_token = os.getenv('INTERNAL_TOKEN', '')
    if _internal_token and request.headers.get('X-Internal-Token') != _internal_token:
        raise HTTPException(401, 'Unauthorized')

    n = min(max(int(req.depth), 1), _MAX_URLS_PER_ROUND)

    # ── ARL loop ───────────────────────────────────────────────────────────────
    _t0      = time.monotonic()
    visited  = set()
    corpus   = ""
    query    = req.topic
    all_pages: list[dict] = []
    rounds   = 0
    # GF-7: traccia tutte le query tentate per evitare duplicati nei fallback
    tried_queries: set[str] = {query.lower()}

    while rounds < _MAX_ROUNDS and (time.monotonic() - _t0) < _TIMEOUT_S:
        # 1. Search ─────────────────────────────────────────────────────────────
        if rounds == 0:
            # GAP-RESEARCH-PARALLEL: round 0 usa 3 query in parallelo per massimizzare
            # la coverage iniziale senza penalità di latenza (asyncio.gather).
            alt_queries = _gen_alt_queries(query)
            if alt_queries:
                search_batches = await asyncio.gather(
                    _pipeline_search(query, n),
                    *[_pipeline_search(q, n) for q in alt_queries],
                )
                # Dedup preservando ordine: priorità alla query principale
                _seen_u: set[str] = set()
                results: list[dict] = []
                for batch in search_batches:
                    for r in batch:
                        if r["url"] not in _seen_u:
                            _seen_u.add(r["url"])
                            results.append(r)
                _logger.debug(
                    "ARL round 0 parallel: %d queries → %d unique URLs",
                    1 + len(alt_queries), len(results),
                )
                # GF-7: registra le alt_queries come già tentate
                for aq in alt_queries:
                    tried_queries.add(aq.lower())
            else:
                results = await _pipeline_search(query, n)
        else:
            results = await _pipeline_search(query, n)

        if not results:
            results = await _ddg_fallback_search(query, n)
        if not results:
            # GF-7: search completamente vuota → prova query alternativa non ancora tentata
            fb_queries = _gen_fallback_queries(req.topic, tried_queries)
            if fb_queries:
                query = fb_queries[0]
                tried_queries.add(query.lower())
                _logger.debug("GF-7: search vuota → fallback query: %r", query)
                rounds += 1
                continue
            break

        # 2. Fetch new URLs only ────────────────────────────────────────────────
        new_urls = [r["url"] for r in results if r["url"] not in visited][:n]
        if not new_urls:
            # GF-7: tutti gli URL già visitati → cambia query invece di arrendersi
            fb_queries = _gen_fallback_queries(req.topic, tried_queries)
            if fb_queries:
                query = fb_queries[0]
                tried_queries.add(query.lower())
                _logger.debug("GF-7: new_urls vuoto → fallback query: %r", query)
                rounds += 1
                continue
            break
        for u in new_urls:
            visited.add(u)

        pages = await asyncio.gather(*[_fetch_page(u) for u in new_urls])
        ok_pages = [p for p in pages if p.get("ok") and p.get("text")]

        # GF-7: pagine fetch tutte fallite (bloccate/vuote) → cambia query
        if not ok_pages:
            fb_queries = _gen_fallback_queries(req.topic, tried_queries)
            if fb_queries:
                query = fb_queries[0]
                tried_queries.add(query.lower())
                _logger.debug("GF-7: ok_pages vuoto → fallback query: %r", query)
                rounds += 1
                continue
            break

        all_pages.extend(ok_pages)

        # 3. Build corpus ───────────────────────────────────────────────────────
        for p in ok_pages:
            corpus += f"\n\n[{p['url']}]\n{p['text'][:1500]}"

        # 4. Coverage check ─────────────────────────────────────────────────────
        coverage = _goal_coverage(req.topic, corpus)
        _logger.debug("ARL round %d: %d pages, coverage=%.2f", rounds, len(all_pages), coverage)
        if coverage >= _MIN_COVERAGE:
            break

        # 5. Refine query for next round ─────────────────────────────────────────
        refined = _refine_query(req.topic, corpus)
        if not refined or refined.lower() in tried_queries:
            # GF-7: _refine_query non produce nulla di nuovo → prova fallback
            fb_queries = _gen_fallback_queries(req.topic, tried_queries)
            if fb_queries:
                query = fb_queries[0]
                tried_queries.add(query.lower())
                _logger.debug("GF-7: refine esaurito → fallback query: %r", query)
            else:
                break
        else:
            query = refined
            tried_queries.add(query.lower())
        rounds += 1

    # ── Response ───────────────────────────────────────────────────────────────
    if not all_pages:
        return {
            "ok": False,
            "error": "Nessuna pagina leggibile trovata (tutte bloccate o vuote).",
        }

    synthesis = ""
    if req.synthesize:
        synthesis = await _synthesize(req.topic, all_pages)

    final_coverage = _goal_coverage(req.topic, corpus)
    elapsed_ms     = round((time.monotonic() - _t0) * 1000)

    return {
        "ok":       True,
        "topic":    req.topic,
        "sources":  [
            {"url": p["url"], "title": p.get("title", ""), "excerpt": p["text"][:500]}
            for p in all_pages
        ],
        "synthesis":  synthesis,
        "count":      len(all_pages),
        # ARL metadata (for debugging / monitoring)
        "arl": {
            "rounds":             rounds + 1,
            "rounds_to_converge": rounds + 1,
            "coverage":           round(final_coverage, 3),
            "elapsed_ms":         elapsed_ms,
            "sources_total":      len(all_pages),
        },
    }


def _gen_alt_queries(goal: str) -> list[str]:
    """GAP-RESEARCH-PARALLEL: genera varianti lessicali per multi-angle search al round 0.

    Zero LLM — analisi sintattica pura. Produce query diverse per ampliare la coverage
    iniziale senza aspettare i round successivi (3× fonti in parallelo ≈ stessa latenza).

    Strategie:
      alt1 — top-3 keyword (sostituisce frasi lunghe con le parole chiave essenziali)
      alt2 — tail context (ultime 3 parole, cattura il complemento tematico)
      alt3 — traduzione EN (U1): per query italiane, aggiunge variante inglese
             per raggiungere documentazione tecnica (prevalentemente in inglese).
    """
    words = [w for w in re.split(r'\W+', goal) if len(w) > 2 and w.lower() not in _STOP_WORDS]
    alts: list[str] = []
    if len(words) >= 4:
        alt1 = ' '.join(words[:3])
        if alt1.lower() != goal.lower():
            alts.append(alt1)
    if len(words) >= 5:
        alt2 = ' '.join(words[-3:])
        if alt2.lower() != goal.lower() and alt2 not in alts:
            alts.append(alt2)
    # U1: alt3 — traduzione EN se query italiana (zero LLM, +30% coverage documentazione tecnica)
    if _is_italian(goal):
        alt3 = _translate_it_en(goal)
        if alt3 and alt3.lower() not in {a.lower() for a in alts} and alt3.lower() != goal.lower():
            alts.append(alt3)
    return alts[:3]


def _gen_fallback_queries(goal: str, tried: set[str]) -> list[str]:
    """GF-7: genera varianti di query non ancora tentate quando new_urls/ok_pages è vuoto.

    Chiamata solo quando il loop si troverebbe ad uscire con 0 nuovi URL o 0 pagine
    leggibili — invece di arrendersi, prova angolazioni diverse:
      v1 — inversione ordine parole chiave (cerca complemento prima del soggetto)
      v2 — aggiunge "tutorial" / "guida" / "come" (disambigua intent informativo)
      v3 — singola keyword più specifica (narrow search su termine principale)

    Zero LLM. Restituisce solo varianti non già in `tried`.
    """
    words = [w for w in re.split(r'\W+', goal) if len(w) > 2 and w.lower() not in _STOP_WORDS]
    candidates: list[str] = []

    # v1 — inversione ultime/prime keyword
    if len(words) >= 3:
        v1 = " ".join(words[len(words)//2:] + words[:len(words)//2])
        candidates.append(v1)

    # v2 — intent informativo esplicito (B-GAP-D: EN-aware prefix)
    kw_core = " ".join(words[:4])
    _v2_prefix = "how to" if not _is_italian(goal) else "come funziona"
    v2 = f"{_v2_prefix} {kw_core}".strip()
    candidates.append(v2)

    # v3 — termine più specifico (seconda keyword, spesso più discriminante)
    if len(words) >= 2:
        v3 = words[1] if len(words[1]) > 4 else (words[0] if len(words[0]) > 4 else "")
        if v3:
            candidates.append(v3)

    # D8: v4 — inversione completa (B-GAP-D: porta D8 nella definizione effettiva)
    if len(words) >= 3:
        v4 = ' '.join(reversed(words))
        if v4 not in set(candidates):
            candidates.append(v4)

    return [c for c in candidates if c and c.lower() not in tried][:3]  # B-GAP-D: era :2, ora :3 per v4


# ─── Search: usa pipeline web_search.py (Brave → Tavily → Wikipedia → HN) ────

async def _pipeline_search(query: str, n: int) -> list[dict]:
    """Usa la pipeline condivisa web_search.py — stessa logica di _run_direct_tools."""
    try:
        from tools.web_search import web_search as _ws
        result = await _ws(query, max_results=n)
        hits = result.get("results", [])
        if hits:
            return [{"url": h["url"], "title": h.get("title", "")} for h in hits if h.get("url")]
    except Exception as exc:
        _logger.debug("pipeline_search fallback: %s", exc)
    return []


async def _ddg_fallback_search(query: str, n: int) -> list[dict]:
    """Fallback DDG HTML parse quando nessuna chiave API è configurata."""
    try:
        _ddg_kl = "it-it" if _is_italian(query) else "en-us"  # B-GAP-D: locale EN-aware
        _ddg_al = "it-IT,it;q=0.9,en;q=0.8" if _ddg_kl == "it-it" else "en-US,en;q=0.9"
        async with httpx.AsyncClient(timeout=10, headers={"User-Agent": _UA, "Accept-Language": _ddg_al}) as c:
            r = await c.get("https://html.duckduckgo.com/html/", params={"q": query, "kl": _ddg_kl})
            if r.status_code != 200:
                return []
            html = r.text
            link_pattern  = re.compile(r'<a[^>]+class="result__url"[^>]*href="([^"]+)"[^>]*>([^<]*)</a>', re.DOTALL)
            title_pattern = re.compile(r'<a[^>]+class="result__a"[^>]*href="[^"]+"[^>]*>([^<]+)</a>', re.DOTALL)
            links  = link_pattern.findall(html)
            titles = [re.sub(r"\s+", " ", t).strip() for t in title_pattern.findall(html)]
            results = []
            for i, (url, _) in enumerate(links[:n]):
                if url.startswith("http"):
                    results.append({"url": url, "title": titles[i] if i < len(titles) else url})
            return results[:n]
    except Exception:
        return []


# ─── Page content extraction ──────────────────────────────────────────────────

async def _fetch_page(url: str, max_chars: int = 2000) -> dict:
    try:
        async with httpx.AsyncClient(timeout=10, follow_redirects=True, headers={"User-Agent": _UA}) as c:
            r = await c.get(url)
            if r.status_code != 200:
                return {"url": url, "ok": False, "error": f"HTTP {r.status_code}"}
            html = r.text
        try:
            import trafilatura
            text = trafilatura.extract(
                html, include_comments=False, include_tables=False,
                favor_recall=True, deduplicate=True,
            ) or ""
        except ImportError:
            text = re.sub(r"<[^>]+>", " ", html)
            text = re.sub(r"\s{2,}", " ", text).strip()
        noise = {"cookie","accept all cookies","privacy policy","terms of service","subscribe","follow us on"}
        lines = [l for l in text.split("\n") if len(l.strip()) > 4 and not any(n in l.lower() for n in noise)]
        text  = "\n".join(lines)
        title_m = re.search(r"<title[^>]*>([^<]+)</title>", html, re.IGNORECASE)
        title   = title_m.group(1).strip()[:120] if title_m else url
        return {"url": url, "title": title, "text": text[:max_chars], "ok": True}
    except Exception as e:
        return {"url": url, "ok": False, "error": str(e)[:100]}


# ─── LLM synthesis (Groq) ─────────────────────────────────────────────────────

async def _synthesize(topic: str, sources: list[dict]) -> str:
    groq_key = os.getenv("GROQ_API_KEY", "")
    if not groq_key:
        return ""
    context = "\n\n".join(
        f"[{i+1}] {s['title']}\n{s['text'][:800]}"
        for i, s in enumerate(sources) if s.get("ok") and s.get("text")
    )[:6000]
    try:
        async with httpx.AsyncClient(timeout=30) as c:
            r = await c.post(
                "https://api.groq.com/openai/v1/chat/completions",
                headers={"Authorization": f"Bearer {groq_key}", "Content-Type": "application/json"},
                json={
                    "model": "llama-3.1-8b-instant",
                    "max_tokens": 700,
                    "messages": [
                        {"role": "system", "content": "Sei un assistente che sintetizza informazioni web. Rispondi sempre in italiano. Sii conciso e preciso."},
                        {"role": "user", "content": (
                            f"Argomento: **{topic}**\n\n"
                            f"Fonti trovate:\n{context}\n\n"
                            "Sintetizza le informazioni principali in 3-5 punti chiave, citando le fonti [N]."
                        )},
                    ],
                },
            )
            if r.status_code == 200:
                _chs = r.json().get("choices") or []
                return (_chs[0].get("message", {}).get("content") or "") if _chs else ""
    except Exception as exc:
        _logger.debug("synthesis error: %s", exc)
    return ""


# ─── Main endpoint ────────────────────────────────────────────────────────────

@router.post("/research")
async def web_research(req: ResearchRequest, request: Request):
    # S-GAP23: X-Internal-Token guard — protegge consumi Groq API da abusi esterni.
    _internal_token = os.getenv('INTERNAL_TOKEN', '')
    if _internal_token and request.headers.get('X-Internal-Token') != _internal_token:
        raise HTTPException(401, 'Unauthorized')

    n = min(max(int(req.depth), 1), _MAX_URLS_PER_ROUND)

    # ── ARL loop ───────────────────────────────────────────────────────────────
    _t0      = time.monotonic()
    visited  = set()
    corpus   = ""
    query    = req.topic
    all_pages: list[dict] = []
    rounds   = 0
    # GF-7: traccia tutte le query tentate per evitare duplicati nei fallback
    tried_queries: set[str] = {query.lower()}

    while rounds < _MAX_ROUNDS and (time.monotonic() - _t0) < _TIMEOUT_S:
        # 1. Search ─────────────────────────────────────────────────────────────
        if rounds == 0:
            # GAP-RESEARCH-PARALLEL: round 0 usa 3 query in parallelo per massimizzare
            # la coverage iniziale senza penalità di latenza (asyncio.gather).
            alt_queries = _gen_alt_queries(query)
            if alt_queries:
                search_batches = await asyncio.gather(
                    _pipeline_search(query, n),
                    *[_pipeline_search(q, n) for q in alt_queries],
                )
                # Dedup preservando ordine: priorità alla query principale
                _seen_u: set[str] = set()
                results: list[dict] = []
                for batch in search_batches:
                    for r in batch:
                        if r["url"] not in _seen_u:
                            _seen_u.add(r["url"])
                            results.append(r)
                _logger.debug(
                    "ARL round 0 parallel: %d queries → %d unique URLs",
                    1 + len(alt_queries), len(results),
                )
                # GF-7: registra le alt_queries come già tentate
                for aq in alt_queries:
                    tried_queries.add(aq.lower())
            else:
                results = await _pipeline_search(query, n)
        else:
            results = await _pipeline_search(query, n)

        if not results:
            results = await _ddg_fallback_search(query, n)
        if not results:
            # GF-7: search completamente vuota → prova query alternativa non ancora tentata
            fb_queries = _gen_fallback_queries(req.topic, tried_queries)
            if fb_queries:
                query = fb_queries[0]
                tried_queries.add(query.lower())
                _logger.debug("GF-7: search vuota → fallback query: %r", query)
                rounds += 1
                continue
            break

        # 2. Fetch new URLs only ────────────────────────────────────────────────
        new_urls = [r["url"] for r in results if r["url"] not in visited][:n]
        if not new_urls:
            # GF-7: tutti gli URL già visitati → cambia query invece di arrendersi
            fb_queries = _gen_fallback_queries(req.topic, tried_queries)
            if fb_queries:
                query = fb_queries[0]
                tried_queries.add(query.lower())
                _logger.debug("GF-7: new_urls vuoto → fallback query: %r", query)
                rounds += 1
                continue
            break
        for u in new_urls:
            visited.add(u)

        pages = await asyncio.gather(*[_fetch_page(u) for u in new_urls])
        ok_pages = [p for p in pages if p.get("ok") and p.get("text")]

        # GF-7: pagine fetch tutte fallite (bloccate/vuote) → cambia query
        if not ok_pages:
            fb_queries = _gen_fallback_queries(req.topic, tried_queries)
            if fb_queries:
                query = fb_queries[0]
                tried_queries.add(query.lower())
                _logger.debug("GF-7: ok_pages vuoto → fallback query: %r", query)
                rounds += 1
                continue
            break

        all_pages.extend(ok_pages)

        # 3. Build corpus ───────────────────────────────────────────────────────
        for p in ok_pages:
            corpus += f"\n\n[{p['url']}]\n{p['text'][:1500]}"

        # 4. Coverage check ─────────────────────────────────────────────────────
        coverage = _goal_coverage(req.topic, corpus)
        _logger.debug("ARL round %d: %d pages, coverage=%.2f", rounds, len(all_pages), coverage)
        if coverage >= _MIN_COVERAGE:
            break

        # 5. Refine query for next round ─────────────────────────────────────────
        refined = _refine_query(req.topic, corpus)
        if not refined or refined.lower() in tried_queries:
            # GF-7: _refine_query non produce nulla di nuovo → prova fallback
            fb_queries = _gen_fallback_queries(req.topic, tried_queries)
            if fb_queries:
                query = fb_queries[0]
                tried_queries.add(query.lower())
                _logger.debug("GF-7: refine esaurito → fallback query: %r", query)
            else:
                break
        else:
            query = refined
            tried_queries.add(query.lower())
        rounds += 1

    # ── Response ───────────────────────────────────────────────────────────────
    if not all_pages:
        return {
            "ok": False,
            "error": "Nessuna pagina leggibile trovata (tutte bloccate o vuote).",
        }

    synthesis = ""
    if req.synthesize:
        synthesis = await _synthesize(req.topic, all_pages)

    final_coverage = _goal_coverage(req.topic, corpus)
    elapsed_ms     = round((time.monotonic() - _t0) * 1000)

    return {
        "ok":       True,
        "topic":    req.topic,
        "sources":  [
            {"url": p["url"], "title": p.get("title", ""), "excerpt": p["text"][:500]}
            for p in all_pages
        ],
        "synthesis":  synthesis,
        "count":      len(all_pages),
        # ARL metadata (for debugging / monitoring)
        "arl": {
            "rounds":             rounds + 1,
            "rounds_to_converge": rounds + 1,
            "coverage":           round(final_coverage, 3),
            "elapsed_ms":         elapsed_ms,
            "sources_total":      len(all_pages),
        },
    }