"""Stage 4 orchestration: the seven-intent routing pipeline (_agent_query_inner) and D1 logging."""
import asyncio
import html
import json
import logging
import os
import re
import time
import uuid
from collections import deque
from datetime import datetime
from typing import Any, Dict, List, Literal, Optional, Tuple
from urllib.parse import quote

import httpx
from pydantic import BaseModel, ConfigDict, Field

from src.config import get_settings, LIBBEE_VERSION
from src.services.staff_service import (
    STAFF_DIRECTORY,
    match_staff_name,
    match_staff_role,
    should_attempt_staff_lookup,
    staff_name_answer,
    staff_role_answer,
)

from src.agentcore.models import AgentResponse, SearchContextPayload
from src.agentcore.constants import (
    ALT_TERMS_RE,
    ASK_LIBRARIAN_URL,
    BOOLEAN_STRATEGY_RE,
    CITATION_CHAIN_RE,
    DUAL_RESOURCE_RE,
    EVENTS_RE,
    FULLTEXT_REQUEST_RE,
    HIGHLY_CITED_RE,
    LIBRARY_HOURS_URL,
    PARTIAL_TITLE_RE,
    PREDATORY_RE,
    PURE_GREETING_RE,
    THESES_RE,
    _INJECTION_RE,
)
from src.agentcore.access_routing import ACCESS_RETRIEVAL_HINT, _is_access_problem
from src.agentcore.utils import (
    _escape,
    _isbn_search_value,
    _get_runtime_config,
    _light_strip_retrieval_boilerplate,
    _normalize_whitespace,
    _primo_clean_url,
    _safe_metrics_bucket,
    _safe_metrics_increment,
    _title_case_topic,
)
from src.agentcore.classify import (
    _is_greeting_menu_followup,
    _is_summary_request,
    _llm_classify,
    _looks_campus_question,
    _looks_library_hours_question,
)
from src.agentcore.libcal import _events_answer, _hours_answer
from src.agentcore.rendering import (
    _ai_tools_footer,
    _contact_footer_for_query,
    _search_trace_block,
    _source_badge,
    _thought_block,
    _tool_urls,
)
from src.agentcore.intents_library import (
    _campus_answer,
    _catalogue_topic,
    _rag_retrieval_query,
    _database_recommendation_answer,
    _fulltext_chain_answer,
    _greeting_menu_clarify_answer,
    _is_database_recommendation_question,
    _library_follow_up,
    _rag_answer,
    _theses_answer,
)
from src.agentcore.intents_search import (
    _alternative_terms_answer,
    _apply_follow_up_action,
    _citation_chain_answer,
    _context_to_dict,
    _derive_resource_type,
    _detect_follow_up,
    _extract_topic,
    _highly_cited_note,
    _parse_year_filters,
    _predatory_eval_answer,
    _prepare_queries,
    _research_snapshot,
    _run_search_mode,
    _search_follow_up,
    _search_strategy_answer,
)
from src.agentcore.intents_general import (
    _general_follow_up,
    _libbee_casual_response,
    _social_follow_up,
    _web_search_result,
)

logger = logging.getLogger(__name__)

_EMAIL_RE = re.compile(r"[\w.+-]+@[\w-]+\.[\w.-]+")
_LONG_DIGITS_RE = re.compile(r"\d{6,}")
_TAG_RE = re.compile(r"<[^>]+>")


# Strong references to in-flight analytics POSTs.
#
# asyncio keeps only WEAK references to tasks: a task created with
# create_task() and then dropped can be garbage-collected before it finishes,
# silently cancelling the request. That is invisible when the network is fast
# and drops writes unpredictably when the handshake is slow. Holding a
# reference until the task completes is the documented fix.
_ANALYTICS_TASKS = set()


def _spawn_background(coro) -> bool:
    """Run coro in the background, keeping a strong reference. True if scheduled."""
    try:
        loop = asyncio.get_running_loop()
    except RuntimeError:
        try:
            loop = asyncio.get_event_loop()
        except Exception:
            return False
    if not loop.is_running():
        return False
    task = loop.create_task(coro)
    _ANALYTICS_TASKS.add(task)
    task.add_done_callback(_ANALYTICS_TASKS.discard)
    return True


def _redact_for_analytics(text: str, max_len: int = 200) -> str:
    """Privacy pass before anything reaches the analytics store: e-mail
    addresses and long digit runs (IDs, phone numbers) are masked and the
    text is truncated. Raw personal identifiers must never be persisted."""
    text = _EMAIL_RE.sub("[email]", text or "")
    text = _LONG_DIGITS_RE.sub("[number]", text)
    return text[:max_len]


def _answer_excerpt(answer_html: str, max_len: int = 800) -> str:
    """Plain-text excerpt of the rendered answer for offline relevance grading
    by the daily KB-gap agent. HTML is stripped and the same redaction applied."""
    text = _TAG_RE.sub(" ", answer_html or "")
    text = re.sub(r"\s+", " ", text).strip()
    return _redact_for_analytics(text, max_len)


# ── Analytics retry buffer ───────────────────────────────────────────────────
# Transient failures reaching the Worker (rate limiting, connection resets)
# previously meant the row was lost for good. Failed payloads are parked here
# and re-attempted on subsequent queries, so a blocked window costs a delay
# rather than data. Bounded so a long outage cannot grow memory without limit.

_PENDING_LOGS: "deque" = deque(maxlen=200)
_PENDING_DROPPED = {"count": 0}

# Rolling record of the last few analytics-write attempts, so the outcome can be
# inspected through /admin/log-status without access to container logs.
_LOG_ATTEMPTS: "deque" = deque(maxlen=15)


def _record_attempt(outcome: str, detail: str = "") -> None:
    _LOG_ATTEMPTS.append({
        "at": datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S"),
        "outcome": outcome,
        "detail": detail[:200],
    })


def analytics_log_status() -> dict:
    """Snapshot of the analytics write path for the admin dashboard."""
    return {
        "pending_buffered": len(_PENDING_LOGS),
        "buffer_capacity": _PENDING_LOGS.maxlen,
        "recent_attempts": list(_LOG_ATTEMPTS)[::-1],
    }


async def _send_with_retry(worker_url: str, token: str, payload: dict,
                           attempts: int = 2, backoff: float = 2.0):
    """_send_log_payload with one retry after a short backoff. Connectivity to
    workers.dev from this host drops for short windows; a single immediate
    retry recovers a meaningful fraction of those without involving the buffer."""
    last_exc = None
    for i in range(attempts):
        try:
            return await _send_log_payload(worker_url, token, payload)
        except Exception as exc:
            last_exc = exc
            if i + 1 < attempts:
                await asyncio.sleep(backoff)
    raise last_exc


async def _send_log_payload(worker_url: str, token: str, payload: dict):
    """POST one analytics payload.

    Returns (status_code, report) where report is the Worker's own JSON verdict.
    This matters because the Worker answers HTTP 200 even when the D1 INSERT
    itself failed, reporting the problem in a 'warning' field - so a status code
    alone cannot distinguish a stored row from a dropped one.
    """
    from src.services.http_client import make_client as _mk
    headers = {"Authorization": f"Bearer {token}"} if token else {}
    async with _mk(timeout=10) as client:
        resp = await client.post(worker_url.rstrip("/") + "/log",
                                 json=payload, headers=headers)
    report = {}
    try:
        body = resp.json()
        if isinstance(body, dict):
            report = {k: body.get(k) for k in ("status", "logged", "schema", "warning")
                      if body.get(k) is not None}
    except Exception:
        report = {"raw": resp.text[:120]}
    return resp.status_code, report


_FLUSHER_STARTED = {"on": False}


def _ensure_periodic_flusher(worker_url: str, token: str) -> None:
    """Start (once) a background loop that retries buffered rows every 90s, so
    parked writes land as soon as connectivity returns instead of waiting for
    the next user query. The task holds a strong reference via _spawn_background.
    Lost on container restart - like the buffer itself - which the keep-alive
    pings are there to make rare."""
    if _FLUSHER_STARTED["on"]:
        return

    async def _loop():
        while True:
            await asyncio.sleep(90)
            if _PENDING_LOGS:
                try:
                    n = await _flush_pending(worker_url, token, max_items=10)
                    if n:
                        _record_attempt("flushed", f"{n} buffered row(s) delivered")
                except Exception:
                    pass

    if _spawn_background(_loop()):
        _FLUSHER_STARTED["on"] = True
        logger.info("Analytics flusher started (90s interval)")


async def _flush_pending(worker_url: str, token: str, max_items: int = 5):
    """Re-attempt parked payloads oldest-first; stop at the first failure so a
    still-blocked Worker is not hammered."""
    sent = 0
    while _PENDING_LOGS and sent < max_items:
        payload = _PENDING_LOGS[0]
        try:
            status, report = await _send_log_payload(worker_url, token, payload)
        except Exception:
            return sent
        if status >= 400 or report.get("logged") is False:
            return sent
        _PENDING_LOGS.popleft()
        sent += 1
    if sent:
        logger.info(f"D1 logging: flushed {sent} buffered row(s); "
                    f"{len(_PENDING_LOGS)} still pending")
    return sent


def _log_agent_query(question: str, response: AgentResponse, start_time: float) -> None:
    """Keep only local operational counters.

    Persistent analytics is written by the Cloudflare gateway after it receives
    the origin response. This prevents duplicate rows and removes the old public
    /log dependency.
    """
    elapsed = time.time() - start_time
    intent = response.intent or ""
    tool = ", ".join(response.tools_used or [])[:60]
    model_used = response.model_used or ""
    result_count = len(response.search_results or [])
    try:
        from app import get_metrics_service
        get_metrics_service().log_query(
            question=_redact_for_analytics(question),
            intent=intent,
            tool=tool,
            model=model_used,
            response_time=elapsed,
            result_count=result_count,
        )
    except Exception:
        pass


async def _library_rag_response(
    question: str,
    history,
    model: str,
    start_time: float,
    *,
    retrieval_hint: str = "",
    top_k: int = 4,
    extra_tools: Tuple[str, ...] = (),
) -> AgentResponse:
    """Answer a library_info question from the knowledge base (RAG).

    Used for classifier-routed library_info questions and, with a retrieval
    hint, for access problems detected before classification.
    """
    query = _rag_retrieval_query(question, history)
    if retrieval_hint:
        query = f"{query} {retrieval_hint}"
    rag_results = []
    try:
        from app import get_rag_service
        rag_results = await get_rag_service().hybrid_search(query, top_k=top_k)
    except Exception as e:
        logger.error(f"RAG search failed: {e}")

    if not rag_results:
        answer = (
            "I couldn't find specific information on that in my knowledge base.<br><br>"
            "Please contact our librarians directly:<br>"
            '📧 <a href="mailto:libse@ku.ac.ae">libse@ku.ac.ae</a><br>'
            f'🔗 <a href="{ASK_LIBRARIAN_URL}" target="_blank">Ask a Librarian</a>'
        )
        answer += _source_badge("ku_library", ASK_LIBRARIAN_URL)
        sources = []
        tools_used = ["rag_no_results"]
        thought = _thought_block("library_info", "rag_no_results", question,
                                 "No matching content was found — I am directing you to Ask a Librarian.")
    else:
        answer = await _rag_answer(question, rag_results, history, model)
        answer += _source_badge("rag", "https://library.ku.ac.ae/")
        sources = list({
            r["source"]: {"title": r.get("title", "Library KB"), "url": r["source"]}
            for r in rag_results if r.get("source")
        }.values())
        retrieval_mode = rag_results[0].get("retrieval_mode", "hybrid")
        tools_used = ["rag_hybrid_search" if retrieval_mode == "hybrid" else "rag_keyword_search"]
        thought = _thought_block("rag_search", tools_used[0], question,
                                 f"The {retrieval_mode} search returned {len(rag_results)} matching passages.")

    follow_up_question, follow_up_suggestions = _library_follow_up(question)
    return AgentResponse(
        answer=thought + answer,
        intent="library_info",
        tools_used=list(extra_tools) + tools_used,
        sources=sources,
        ask_librarian=not bool(rag_results),
        model_used=model,
        response_time=time.time() - start_time,
        follow_up_question=follow_up_question,
        follow_up_suggestions=follow_up_suggestions,
    )


async def _agent_query_inner(
    question: str,
    history,
    model: str,
    client_state,
    start_time: float,
) -> AgentResponse:

    settings = get_settings()
    if model == "gpt" and not settings.openai_api_key and settings.anthropic_api_key:
        model = "claude"
    elif model == "claude" and not settings.anthropic_api_key and settings.openai_api_key:
        model = "gpt"

    # ── Prompt injection detection ────────────────────────────────────────────
    if question and _INJECTION_RE.search(question):
        _safe_metrics_bucket("intents", "injection_blocked")
        return AgentResponse(
            answer=(
                "I'm sorry, but I can't process that request. "
                "I'm LibBee, the KU Library AI Assistant — here to help with "
                "library services, research, and academic resources. "
                f'How can I help you today? <a href="{ASK_LIBRARIAN_URL}" target="_blank">Ask a Librarian</a>'
            ),
            intent="blocked",
            tools_used=["injection_guard"],
            model_used=model,
            response_time=time.time() - start_time,
        )

    if not question:
        follow_up_question, follow_up_suggestions = _social_follow_up()
        return AgentResponse(
            answer="Please type a question and I'll do my best to help!" + _source_badge("libbee"),
            intent="social",
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if PURE_GREETING_RE.match(question):
        follow_up_question, follow_up_suggestions = _social_follow_up()
        return AgentResponse(
            answer=(
                _get_runtime_config().get("welcome_message", "").strip()
                or (
                    "Hi! I'm <strong>LibBee</strong>, the Khalifa University Library AI Assistant.<br><br>"
                    "I can help you find articles and books, search databases, access full text, "
                    "request Interlibrary Loan (ILL), and answer questions about library services and staff."
                )
                + _source_badge("libbee")
            ),
            intent="social_greeting",
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    staff_match = match_staff_name(question) if should_attempt_staff_lookup(question) else None
    if staff_match:
        _safe_metrics_bucket("intents", "staff_lookup")
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        return AgentResponse(
            answer=_thought_block("staff_lookup", "staff_name_match", question) + staff_name_answer(staff_match) + _source_badge("ku_library", "https://library.ku.ac.ae/librarystaff"),
            intent="library_info",
            tools_used=["staff_name_match"],
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    staff_role_match = match_staff_role(question) if should_attempt_staff_lookup(question) else None
    if staff_role_match:
        _safe_metrics_bucket("intents", "staff_lookup")
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        return AgentResponse(
            answer=_thought_block("staff_lookup", "staff_role_match", question) + staff_role_answer(staff_role_match, question) + _source_badge("ku_library", "https://library.ku.ac.ae/librarystaff"),
            intent="library_info",
            tools_used=["staff_role_match"],
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if _is_greeting_menu_followup(question, history):
        follow_up_question, follow_up_suggestions = _social_follow_up()
        return AgentResponse(
            answer=_thought_block("social_greeting", "greeting_menu", question) + _greeting_menu_clarify_answer() + _source_badge("libbee"),
            intent="social_greeting",
            is_follow_up=True,
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if _looks_library_hours_question(question):
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        hours_html = await _hours_answer()
        return AgentResponse(
            answer=_thought_block("hours", "libcal_live", question) + hours_html + _source_badge("ku_library", LIBRARY_HOURS_URL),
            intent="library_info",
            tools_used=["libcal_hours_lookup"],
            ask_librarian=False,
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if EVENTS_RE.search(question):
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        events_html = await _events_answer()
        return AgentResponse(
            answer=_thought_block("events", "libcal_events", question)
                   + events_html + _source_badge("ku_library", "https://kustar.libcal.com/calendar/events"),
            intent="library_info",
            tools_used=["libcal_events_lookup"],
            ask_librarian=False,
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if _looks_campus_question(question):
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        return AgentResponse(
            answer=_thought_block("campus", "campus_hardcoded", question) + _campus_answer() + _source_badge("ku_library", "https://library.ku.ac.ae/"),
            intent="library_info",
            tools_used=["campus_hardcoded"],
            ask_librarian=False,
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    # ── E-resource access problems → knowledge base ───────────────────────────
    # Checked before the database-recommendation and full-text handlers, whose
    # regexes would otherwise catch "access to databases off campus" or
    # "can't access ScienceDirect". Skips the LLM classifier entirely.
    if _is_access_problem(question):
        _safe_metrics_bucket("intents", "access_problem")
        return await _library_rag_response(
            question, history, model, start_time,
            retrieval_hint=ACCESS_RETRIEVAL_HINT, top_k=5,
            extra_tools=("access_problem_rag",),
        )

    if _is_database_recommendation_question(question):
        answer = _database_recommendation_answer(question)
        answer += _contact_footer_for_query(question, None)
        answer += _source_badge("ku_library", "https://library.ku.ac.ae/eresources")
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        return AgentResponse(
            answer=_thought_block("database_rec", "database_recommendation", question) + answer,
            intent="library_info",
            tools_used=["database_recommendation"],
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    is_follow_up, follow_up_action, base_context = _detect_follow_up(question, client_state)

    # ── Catalogue availability ────────────────────────────────────────────────
    _CATALOGUE_RE = re.compile(
        r"\b("
        r"available in (the )?(ku|khalifa) library"
        r"|in (the )?(ku|khalifa) library"
        r"|does (the )?(ku|khalifa) library have"
        r"|does (the )?library (have|carry|stock|hold)"
        r"|(ku|khalifa) library (has|have|carry|holds?|stocks?)"
        r"|ku library (books?|copies|titles?)"
        r")\b",
        re.IGNORECASE,
    )
    _BOOK_RE = re.compile(r"\b(e[- ]?books?|text[- ]?books?|books?|copy|copies|titles?)\b", re.IGNORECASE)

    catalogue_books_request = bool(_CATALOGUE_RE.search(question) and _BOOK_RE.search(question))

    if is_follow_up and base_context:
        _safe_metrics_increment("follow_up_hits")
        context = _apply_follow_up_action(base_context, follow_up_action)

        if follow_up_action == "alt_terms":
            alt_answer = await _alternative_terms_answer(question, base_context, model)
            follow_up_question, follow_up_suggestions = await _search_follow_up(base_context, model)
            return AgentResponse(
                answer=_thought_block("library_info", "alt_terms", question) + alt_answer + _source_badge("libbee"),
                intent="library_info",
                tools_used=["alt_terms"],
                model_used=model,
                response_time=time.time() - start_time,
                follow_up_question=follow_up_question,
                follow_up_suggestions=follow_up_suggestions,
                search_context=_context_to_dict(base_context),
                is_follow_up=True,
            )

        if follow_up_action in {"summarize_topic", "deep_research_tools", "best_databases"}:
            context = await _prepare_queries(question, context, model, True)
            if follow_up_action == "summarize_topic":
                answer, search_results, sources = await _research_snapshot(context, model)
            else:
                answer = (
                    f"{_search_trace_block(question, context)}"
                    f"<strong>Research guide for {_escape(context.display_topic or context.topic)}</strong><br><br>"
                    f"Here are the best AI tools and resources for a deep dive on this topic."
                    + _source_badge("libbee")
                    + _ai_tools_footer(context)
                )
                search_results = []
                sources = []
            follow_up_question, follow_up_suggestions = await _search_follow_up(context, model, summary_mode=True)
            _safe_metrics_increment("search_handoffs")
            return AgentResponse(
                answer=answer,
                intent=context.intent,
                tools_used=["follow_up_resolution", follow_up_action],
                search_results=search_results,
                sources=sources,
                model_used=model,
                response_time=time.time() - start_time,
                corrected_query=context.topic,
                natural_query=context.ai_tool_query,
                database_query=context.primo_boolean_query,
                ai_tool_query=context.ai_tool_query,
                primo_boolean_query=context.primo_boolean_query,
                primo_search_url=_primo_clean_url(context),
                primo_ai_url=_tool_urls(context).get("primo_ai"),
                pubmed_search_url=_tool_urls(context).get("pubmed"),
                follow_up_question=follow_up_question,
                follow_up_suggestions=follow_up_suggestions,
                search_context=_context_to_dict(context),
                is_follow_up=True,
            )

        context = await _prepare_queries(question, context, model, True)
        search_output, follow_up_output = await asyncio.gather(
            _run_search_mode(question, context, model, True),
            _search_follow_up(context, model),
        )
        answer, search_results, sources, source_url = search_output
        follow_up_question, follow_up_suggestions = follow_up_output
        if follow_up_action == "review_articles_only":
            answer += "<br><br>Use the destination database’s publication-type filter to select review articles. A review article and a peer-reviewed article are different categories."
        return AgentResponse(
            answer=answer,
            intent=context.intent,
            tools_used=["follow_up_resolution", follow_up_action or "contextual_refinement"] + (["primo_api_search"] if context.source == "primo" and search_results else []),
            search_results=search_results,
            sources=sources,
            model_used=model,
            response_time=time.time() - start_time,
            corrected_query=context.topic,
            natural_query=context.ai_tool_query,
            database_query=context.primo_boolean_query,
            ai_tool_query=context.ai_tool_query,
            primo_boolean_query=context.primo_boolean_query,
            primo_search_url=_primo_clean_url(context),
            primo_ai_url=_tool_urls(context).get("primo_ai"),
            pubmed_search_url=_tool_urls(context).get("pubmed"),
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
            search_context=_context_to_dict(context),
            is_follow_up=True,
        )

    # ── Pre-classifier specialist handlers ───────────────────────────────────

    if FULLTEXT_REQUEST_RE.search(question):
        ft_answer = _fulltext_chain_answer(question)
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        return AgentResponse(
            answer=_thought_block("library_info", "fulltext_chain", question,
                                  "Identified a full-text access request. Returning the KU full-text access chain.") + ft_answer + _source_badge("ku_library", "https://library.ku.ac.ae/ill/"),
            intent="library_info",
            tools_used=["fulltext_chain"],
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if THESES_RE.search(question):
        th_answer = _theses_answer()
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        return AgentResponse(
            answer=_thought_block("library_info", "theses_guide", question,
                                  "Identified a theses/repository question.") + th_answer + _source_badge("ku_library", "https://khazna.ku.ac.ae"),
            intent="library_info",
            tools_used=["theses_guide"],
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if PREDATORY_RE.search(question):
        pr_answer = _predatory_eval_answer()
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        return AgentResponse(
            answer=_thought_block("library_info", "predatory_eval", question,
                                  "Identified a question about evaluating journals/peer review.") + pr_answer + _source_badge("ku_library", "https://library.ku.ac.ae/eresources"),
            intent="library_info",
            tools_used=["predatory_eval"],
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if CITATION_CHAIN_RE.search(question):
        cc_answer = _citation_chain_answer()
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        return AgentResponse(
            answer=_thought_block("library_info", "citation_chain", question,
                                  "Identified a citation tracing / forward-backward search question.") + cc_answer + _source_badge("ku_library", "https://library.ku.ac.ae/eresources"),
            intent="library_info",
            tools_used=["citation_chain"],
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if BOOLEAN_STRATEGY_RE.search(question):
        strategy_answer, _plan = await _search_strategy_answer(question, model)
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        return AgentResponse(
            answer=_thought_block("library_info", "search_strategy", question,
                                  "Identified a search strategy / boolean building request.") + strategy_answer + _source_badge("libbee"),
            intent="library_info",
            tools_used=["search_strategy_explain"],
            model_used=model,
            response_time=time.time() - start_time,
            database_query=_plan.get("boolean"),
            natural_query=_plan.get("natural"),
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if ALT_TERMS_RE.search(question):
        alt_answer = await _alternative_terms_answer(question, None, model)
        follow_up_question, follow_up_suggestions = _library_follow_up(question)
        return AgentResponse(
            answer=_thought_block("library_info", "alt_terms", question) + alt_answer + _source_badge("libbee"),
            intent="library_info",
            tools_used=["alt_terms"],
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    # Catalogue requests use the same planner, filters and records as subject searches.
    cls_result = ({"intent": "search_academic"} if catalogue_books_request or _isbn_search_value(question)
                  else await _llm_classify(question, history, model))
    intent = cls_result.get("intent", "general")
    _safe_metrics_bucket("intents", intent)
    casual_hint = cls_result.get("casual_answer", "")

    if intent == "social":
        answer = (
            casual_hint
            if casual_hint and len(casual_hint.strip()) > 20
            else await _libbee_casual_response(question, history, model, casual_hint)
        )
        follow_up_question, follow_up_suggestions = _social_follow_up()
        return AgentResponse(
            answer=_thought_block("social", "libbee_casual", question) + answer + _source_badge("libbee"),
            intent="social_greeting",
            tools_used=["libbee_casual"],
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if intent == "sensitive":
        _safe_metrics_bucket("intents", "sensitive_blocked")
        follow_up_question, follow_up_suggestions = _social_follow_up()
        return AgentResponse(
            answer=(
                "That's not something I'm able to comment on. "
                "As the KU Library AI Assistant, I'm here to support your academic "
                "and research needs — finding articles, accessing databases, "
                "library services, and research tools.<br><br>"
                "Is there something I can help you with today? "
                f'<a href="{ASK_LIBRARIAN_URL}" target="_blank">💬 Ask a Librarian</a>'
            ),
            intent="sensitive_blocked",
            tools_used=["sensitive_intent_guard"],
            model_used=model,
            response_time=time.time() - start_time,
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
        )

    if intent == "library_info":
        return await _library_rag_response(question, history, model, start_time)

    if intent in ("search_academic", "search_medical"):
        topic = await _extract_topic(question, model)
        topic = _title_case_topic(topic)
        year_from, year_to = _parse_year_filters(question)

        context = SearchContextPayload(
            context_id=str(uuid.uuid4()),
            topic=topic,
            display_topic=topic,
            intent=intent,
            source="pubmed" if re.search(r"\bpubmed\b", question, re.I) else "primo",
            resource_type="books" if catalogue_books_request else _derive_resource_type(question),
            peer_reviewed=bool(re.search(r"\bpeer[- ]reviewed\b", question, re.IGNORECASE)),
            open_access=bool(re.search(r"\bopen access\b", question, re.IGNORECASE)),
            year_from=year_from,
            year_to=year_to,
        )

        context = await _prepare_queries(question, context, model, False)
        summary_mode = _is_summary_request(question)
        deep_research_mode = bool(re.search(
            r"\b(deep research|deep dive|systematic review|full literature review|exhaustive)\b",
            question, re.IGNORECASE,
        ))
        is_highly_cited = bool(HIGHLY_CITED_RE.search(question))

        if summary_mode or deep_research_mode:
            snapshot_output, follow_up_output = await asyncio.gather(
                _research_snapshot(context, model),
                _search_follow_up(context, model, summary_mode=True),
            )
            answer, search_results, sources = snapshot_output
            follow_up_question, follow_up_suggestions = follow_up_output
            if deep_research_mode and "Research guide" not in answer and "AI tools" not in answer:
                answer += f"<br><br>{_ai_tools_footer(context)}"
            if is_highly_cited:
                answer += _highly_cited_note(_escape(topic))
            _safe_metrics_increment("search_handoffs")
            return AgentResponse(
                answer=answer,
                intent=intent,
                tools_used=["research_snapshot"] + (["primo_api_search"] if context.source == "primo" and search_results else []),
                search_results=search_results,
                sources=sources,
                model_used=model,
                response_time=time.time() - start_time,
                corrected_query=context.topic,
                natural_query=context.ai_tool_query,
                database_query=context.primo_boolean_query,
                ai_tool_query=context.ai_tool_query,
                primo_boolean_query=context.primo_boolean_query,
                primo_search_url=_primo_clean_url(context),
                primo_ai_url=_tool_urls(context).get("primo_ai"),
                pubmed_search_url=_tool_urls(context).get("pubmed"),
                follow_up_question=follow_up_question,
                follow_up_suggestions=follow_up_suggestions,
                search_context=_context_to_dict(context),
            )

        search_output, follow_up_output = await asyncio.gather(
            _run_search_mode(question, context, model, False),
            _search_follow_up(context, model),
        )
        answer, search_results, sources, source_url = search_output
        follow_up_question, follow_up_suggestions = follow_up_output
        if is_highly_cited:
            answer += _highly_cited_note(_escape(topic))
        return AgentResponse(
            answer=answer,
            intent=intent,
            tools_used=["primo_browser_link" if context.source == "primo" else "pubmed_browser_link"] + (["primo_api_search" if context.source == "primo" else "scholarly_evidence"] if search_results else []),
            search_results=search_results,
            sources=sources,
            model_used=model,
            response_time=time.time() - start_time,
            corrected_query=context.topic,
            natural_query=context.ai_tool_query,
            database_query=context.primo_boolean_query,
            ai_tool_query=context.ai_tool_query,
            primo_boolean_query=context.primo_boolean_query,
            primo_search_url=_primo_clean_url(context),
            primo_ai_url=_tool_urls(context).get("primo_ai"),
            pubmed_search_url=_tool_urls(context).get("pubmed"),
            follow_up_question=follow_up_question,
            follow_up_suggestions=follow_up_suggestions,
            search_context=_context_to_dict(context),
        )

    # Preserve the provider's actual source metadata. A failed web tool must
    # never make an ordinary model answer appear live or source-verified.
    web_result = await _web_search_result(question, history, model)
    live = bool(web_result.get("live_search"))
    badge = "web_live" if live and intent == "general_recent" else "web" if live else "llm"
    approach = intent if live else "general_knowledge"
    answer = web_result["answer"] + _source_badge(badge)
    follow_up_question, follow_up_suggestions = _general_follow_up(question)
    return AgentResponse(
        answer=_thought_block(approach, "web_search" if live else "llm_fallback", question) + answer,
        intent="general_recent" if intent == "general_recent" else "general",
        tools_used=web_result.get("tools_used", ["llm_fallback"]),
        sources=web_result.get("sources", []),
        model_used=web_result.get("model_used", model),
        response_time=time.time() - start_time,
        follow_up_question=follow_up_question,
        follow_up_suggestions=follow_up_suggestions,
    )