/**
 * useConversationManager.ts — S-CM1
 *
 * Estratto da MainWorkspace.tsx (S761-CM1).
 * Gestisce il ciclo vita della conversazione: sendMessage, streaming, handlers.
 *
 * Riduzione MainWorkspace: ~1267 → ~720 righe (-43%).
 * Invariante PR2: solo frontend, zero side-effect backend.
 */
import { useState, useRef, useCallback, useEffect } from "react";
import type * as React from "react";
import { toast } from "sonner";

import type { ConfirmRequest } from "@/lib/agentLoop";
import type { Suggestion }     from "@/lib/agent/SmartSuggestions";
import type { PreviewRuntimeError } from "@/components/PreviewSandbox";
import {
  getMessages, getConversations, saveConversations, saveMessages,
  createConversation, updateConversationTitle, touchConversation,
  type Message,
} from "@/lib/storage";
import {
  getAnyToken, buildMessages, buildRawMessages, guessCategory,
} from "@/lib/messageBuilders";
import { streamWithFallback } from "@/lib/providerChain";
import { getCurrentSegment }   from "@/lib/topicBoundary";
import { buildFileContext }     from "@/lib/fileReader";
import { exportAsJSON, importFromJSON } from "@/lib/export";
import { saveSession }          from "@/lib/sessionMemory";
import { classifyTask, getTopInterpretations } from "@/lib/taskClassifier";
import { detectAmbiguity }      from "@/lib/ambiguityDetector";
import { useUIStore }           from "@/store/uiStore";
import { useConversationStore } from "@/store/conversationStore";
import { useWorkspaceStore }    from "@/store/workspaceStore";
import { useChatStore }         from "@/store/chatStore";
import { useTaskStore, RESUME_WINDOW_MS } from "@/store/taskStore";
import { useSlashCommands }     from "@/hooks/useSlashCommands";

// S439: lazy singleton — identico al pattern MainWorkspace (module-level cache)
let _agentLoopPromise: Promise<typeof import("@/lib/agentLoop")> | null = null;
const _loadAgentLoop = (): Promise<typeof import("@/lib/agentLoop")> =>
  (_agentLoopPromise ??= import("@/lib/agentLoop"));

export interface ConversationManagerResult {
  /** S713: streaming content separato — aggiorna solo il componente streaming */
  streamingContent: string;
  streamingMsgIdRef: React.MutableRefObject<string | null>;
  /** S296: SmartSuggestions chips */
  suggestions: Suggestion[];
  setSuggestions: React.Dispatch<React.SetStateAction<Suggestion[]>>;
  /** S352: resume task interrotto */
  resumeTask: { id: string; goal: string } | null;
  setResumeTask: React.Dispatch<React.SetStateAction<{ id: string; goal: string } | null>>;
  /** InlineConfirmation */
  pendingConfirm: ConfirmRequest | null;
  setPendingConfirm: React.Dispatch<React.SetStateAction<ConfirmRequest | null>>;
  confirmResolverRef: React.MutableRefObject<((v: boolean) => void) | null>;
  /** Refs esposti per il render di MainWorkspace */
  abortRef: React.MutableRefObject<AbortController | null>;
  importFileRef: React.MutableRefObject<HTMLInputElement | null>;
  /** Handlers */
  sendMessage: (text: string, prefixContext?: string, opts?: { resumeTaskId?: string }) => Promise<void>;
  handleRetry: () => void;
  handleAutoFix: (error: string, code: string, filename: string) => void;
  handleExport: () => void;
  handleImport: () => void;
  handleImportFile: (e: React.ChangeEvent<HTMLInputElement>) => Promise<void>;
  handlePreviewRuntimeError: (errors: PreviewRuntimeError[]) => void;
  handlePreviewVerified: () => void;
  handleRunRequest: (code: string, filename: string) => void;
  executeSlashCommand: ReturnType<typeof useSlashCommands>;
}

export function useConversationManager(): ConversationManagerResult {

  // ── Streaming display state (S713) ────────────────────────────────────────
  const [_streamContent, _setStreamContent] = useState("");
  const _streamMsgIdRef = useRef<string | null>(null);

  // ── UI state ───────────────────────────────────────────────────────────────
  const [suggestions,  setSuggestions]  = useState<Suggestion[]>([]);
  const [resumeTask,   setResumeTask]   = useState<{ id: string; goal: string } | null>(null);

  // ── InlineConfirmation ─────────────────────────────────────────────────────
  const [pendingConfirm, setPendingConfirm] = useState<ConfirmRequest | null>(null);
  const confirmResolverRef = useRef<((v: boolean) => void) | null>(null);

  // ── Streaming refs ─────────────────────────────────────────────────────────
  const abortRef               = useRef<AbortController | null>(null);
  const importFileRef          = useRef<HTMLInputElement | null>(null);
  const streamingConvIdRef     = useRef<string | null>(null);
  const streamingMsgIdRef      = useRef<string | null>(null);
  const hasFirstChunkRef       = useRef(false);
  const agentLiveStatusRef     = useRef("");
  const _lastSaveRef           = useRef(0);
  const _sendMsgRef            = useRef<((text: string, prefix?: string) => Promise<void>) | null>(null);
  const _previewAutoRepairFired = useRef(false);
  const _isSafariAbortRef      = useRef<boolean>(false);
  const _pendingSteerRef       = useRef<string | null>(null); // V7-5

  // ── Store subscriptions ────────────────────────────────────────────────────
  const isStreaming        = useChatStore(s => s.isStreaming);
  const setIsStreaming     = useChatStore(s => s.setIsStreaming);
  const setAgentMode       = useChatStore(s => s.setAgentMode);
  const setThinkMode       = useChatStore(s => s.setThinkMode);
  const setPendingDisambig = useChatStore(s => s.setPendingDisambig);
  const setAgentLiveStatus = useChatStore(s => s.setAgentLiveStatus);
  const setInput           = useChatStore(s => s.setInput);
  const setAttachedFiles   = useChatStore(s => s.setAttachedFiles);

  const activeId         = useConversationStore(s => s.activeId);
  const messages         = useConversationStore(s => s.messages);
  const setMessages      = useConversationStore(s => s.setMessages);
  const setConversations = useConversationStore(s => s.setConversations);
  const setActiveId      = useConversationStore(s => s.setActiveId);

  const previewHtml  = useWorkspaceStore(s => s.previewHtml);
  const setRunCode   = useWorkspaceStore(s => s.setRunCode);

  const setTab    = useUIStore(s => s.setActiveTab);
  const addAlert  = useUIStore(s => s.addAlert);

  // ── _persistMsgs — stable callback ────────────────────────────────────────
  const _persistMsgs = useCallback(
    (id: string, msgs: Message[], opts?: { skipLocalStorage?: boolean }) =>
      saveMessages(id, msgs, opts),
    [],
  );

  // ── executeSlashCommand ────────────────────────────────────────────────────
  const executeSlashCommand = useSlashCommands({
    setAgentMode,
    persistMsgs: _persistMsgs,
    sendMsgRef:  _sendMsgRef,
  });

  // ── sendMessage ────────────────────────────────────────────────────────────
  const sendMessage = useCallback(async (
    text: string,
    prefixContext?: string,
    opts?: { resumeTaskId?: string },
  ) => {
    const _chat = useChatStore.getState();
    const _conv = useConversationStore.getState();
    const _ws   = useWorkspaceStore.getState();

    const fileCtx  = buildFileContext(_chat.attachedFiles);
    // V7-5: prepend pending steer hint se non streaming
    const _sh = _pendingSteerRef.current;
    if (_sh) _pendingSteerRef.current = null;
    const userText = (prefixContext ? prefixContext + "\n\n" : "") +
      (_sh ? `[Contesto: ${_sh}]\n` : "") + text.trim() + fileCtx;
    if (!userText) return;

    // S400-MANUS: live guidance — inietta istruzione nel loop in esecuzione
    if (_chat.isStreaming) {
      if (_chat.agentMode && text.trim()) {
        const _cid = _conv.activeId;
        if (_cid) {
          const _guidanceMsg: Message = {
            id: crypto.randomUUID(), role: "user",
            content: text.trim(), createdAt: Date.now(), isGuidance: true,
          };
          const _withGuidance = [..._conv.messages, _guidanceMsg];
          setMessages(_withGuidance);
          _persistMsgs(_cid, _withGuidance);
          import("@/lib/liveGuidanceStore").then(m => m.liveGuidanceStore.push(text.trim())).catch(() => {});
          setInput(""); setAttachedFiles([]);
        }
      }
      return;
    }

    const _isPending    = !!_chat.pendingDisambig;
    const _disambigOrig = _chat.pendingDisambig?.originalQuery ?? "";
    if (_isPending) setPendingDisambig(null);
    setInput(""); setAttachedFiles([]);

    let convId       = _conv.activeId;
    let currentConvs = _conv.conversations;

    if (!convId) {
      const conv   = createConversation();
      currentConvs = [conv, ..._conv.conversations];
      setConversations(currentConvs);
      saveConversations(currentConvs);
      setActiveId(conv.id);
      convId = conv.id;
    }

    const userMsg: Message  = { id: crypto.randomUUID(), role: "user", content: userText, createdAt: Date.now() };
    const currentMsgs       = _conv.activeId === convId ? _conv.messages : getMessages(convId);
    const withUser          = [...currentMsgs, userMsg];

    // S97-Bug2: topic boundary cut
    const _prevSeg    = getCurrentSegment();
    const _newCat     = guessCategory(userText);
    const INCOMPAT    = new Set(["realtime:coding","coding:realtime","news:coding","coding:news"]);
    const _isNewTopic = _prevSeg && INCOMPAT.has(`${_prevSeg.category}:${_newCat}`);
    let msgsForLLM    = _isNewTopic ? [userMsg] : withUser;
    if (_isPending && _disambigOrig) {
      const enriched = `[Query originale]: ${_disambigOrig}\n\n[Chiarimento]: ${userText}`;
      msgsForLLM = msgsForLLM.map(m => m.id === userMsg.id ? { ...m, content: enriched } : m);
    }
    setMessages(withUser);
    _persistMsgs(convId, withUser);

    // S264: smart title sincrono
    if (currentMsgs.length === 0) {
      const _FILLER = /^(ciao|hey|hei|salve|ok|okay|allora|quindi|comunque|per favore|per piacere|grazie|perfavore|puoi|potresti|riesci|dimmi|spiegami|vorrei|voglio|ho bisogno|aiutami|aiuto|please|can you|could you|tell me|explain|help me|i need|i want|what is|what are|how do|how to|come|cosa|chi|quando|dove|perch[eé]|qual[ei]|in che|in modo|fammi|fai|crea|scrivi|genera|fatti|devo|mi serv[ei]|ho un|ho una|[ée] possibile|sai|hai|conosci|sai dirmi|c['']s*[eè]|come funziona|come si|mi puoi|mi potresti)\s+/i;
      const _raw  = text.trim().replace(/^[\s\u2022\u2019""''«»]+/, '');
      const _clean = _raw.replace(_FILLER, '').trim();
      const _src  = (_clean.length > 4 ? _clean : _raw);
      const _words = _src.split(/\s+/).filter(w => w.length > 1).slice(0, 6).join(' ');
      const _smartTitle = _words.length > 0
        ? (_words.charAt(0).toUpperCase() + _words.slice(1)).slice(0, 54)
        : 'Nuova conversazione';
      const updated = updateConversationTitle(currentConvs, convId, _smartTitle);
      setConversations(updated); saveConversations(updated);
    }

    // S435: Auto-detection modalità
    const _AUTO_AGENT_TYPES = new Set([
      "full_app","architecture","search_and_report","code_generation",
      "debug","refactor","data_analysis","realtime_query",
    ]);
    const _AUTO_THINK_TYPES = new Set(["explanation","math_calculation"]);
    const _isAutoMode = !_chat.agentMode && !_chat.thinkMode;
    let _effectiveAgentMode = _chat.agentMode;
    let _effectiveThinkMode = _chat.thinkMode;
    if (_isAutoMode) {
      const _autoCls = classifyTask(text);
      _effectiveAgentMode = _autoCls.complexity >= 6 || _autoCls.needsPlan ||
        _AUTO_AGENT_TYPES.has(_autoCls.type);
      _effectiveThinkMode = !_effectiveAgentMode && (
        _AUTO_THINK_TYPES.has(_autoCls.type) || _autoCls.complexity >= 7
      );
      if (_effectiveAgentMode) setAgentMode(true);
      else if (_effectiveThinkMode) setThinkMode(true);
    }

    // S99: Ambiguity Detector
    if (_effectiveAgentMode && !_isPending) {
      const _topInterps = getTopInterpretations(text, 3);
      const _primaryCls = classifyTask(text);
      const _amb        = detectAmbiguity(text, _primaryCls, _topInterps);
      if (_amb.isAmbiguous && _amb.question) {
        const qaMsg: Message = { id: crypto.randomUUID(), role: "assistant", content: `🤔 ${_amb.question}`, createdAt: Date.now() };
        const withQA = [...withUser, qaMsg];
        setMessages(withQA); _persistMsgs(convId, withQA);
        setPendingDisambig({ originalQuery: text });
        return;
      }
    }

    const assistantMsg: Message = { id: crypto.randomUUID(), role: "assistant", content: "…", createdAt: Date.now() };
    setMessages([...withUser, assistantMsg]);
    setIsStreaming(true);
    setTab("chat");
    streamingConvIdRef.current = convId;
    streamingMsgIdRef.current  = assistantMsg.id;
    _streamMsgIdRef.current    = assistantMsg.id;
    hasFirstChunkRef.current   = false;

    const abort = new AbortController();
    abortRef.current = abort;

    let accumulated       = "";
    let rafId: number | null = null;
    let _lastPersistedLen = 0;
    const PERSIST_CHUNK   = 500;
    let _taskId: string | null = null;

    const flushChunk = () => {
      rafId = null;
      if (streamingConvIdRef.current !== convId) return;
      _setStreamContent(accumulated);
      if (accumulated.length - _lastPersistedLen >= PERSIST_CHUNK) {
        _lastPersistedLen = accumulated.length;
        _persistMsgs(convId, withUser.concat({ ...assistantMsg, content: accumulated }), { skipLocalStorage: true });
      }
    };

    try {
      const _onChunk = (chunk: string) => {
        accumulated += chunk;
        if (!hasFirstChunkRef.current) {
          hasFirstChunkRef.current = true;
          const ws = "Scrittura risposta in tempo reale...";
          agentLiveStatusRef.current = ws;
          setAgentLiveStatus(ws);
        }
        if (rafId !== null) return;
        rafId = requestAnimationFrame(flushChunk);
      };

      const _onAgentStatus = (t: string) => {
        agentLiveStatusRef.current = t;
        setAgentLiveStatus(t);
        if (streamingMsgIdRef.current)
          setMessages(prev => prev.map(m => m.id === streamingMsgIdRef.current ? { ...m, agentStatus: t } : m));
      };

      if (_effectiveAgentMode) {
        const ts0 = useTaskStore.getState();

        // P4-1: se VITE_BACKEND_URL è configurato e il backend è healthy → SSE Railway
        const _backendUrl = (import.meta.env.VITE_BACKEND_URL ?? "").replace(/\/$/, "");
        const { isBackendHealthy: _isBH } = await import("@/lib/backendClient");
        const _useBackendSSE = !!_backendUrl && _isBH() && !opts?.resumeTaskId;

        if (_useBackendSSE) {
          // ── P4-1: Backend SSE path ────────────────────────────────────────
          const { startAgentTaskSSE } = await import("@/lib/agentSSE");
          const _sseCtx = buildRawMessages(msgsForLLM, _ws.openFile, _ws.settings) as unknown as import('@/lib/apiTypes').ApiMsg[];
          // P17-F3-FIX: userText include fileCtx con visionDescription — il backend SSE
          // riceve la descrizione AI delle immagini allegate (buildFileContext già formatta
          // visionDescription/visionTags/visionTextInImage come testo strutturato).
          // Prima: text (grezzo) → backend cieco sulle immagini. Ora: userText → contesto pieno.
          const sseHandle = startAgentTaskSSE(userText, _sseCtx, 8);

          // P16-F1: S399-GUARD ha rifiutato il task (SSE già attivo) — fallback locale
          if (sseHandle.rejected) {
            /* [UCM] SSE rejected fallback */
            // Re-route verso il path locale senza SSE (agentLoop in-browser)
            throw new Error("SSE_REJECTED");
          }

          _taskId = sseHandle.taskId;

          // Quando l'utente clicca "Stop" → cancella anche il task SSE
          abort.signal.addEventListener("abort", () => sseHandle.cancel(), { once: true });

          // Token streaming dal backend → stessa pipeline UI del local agent
          const _sseOnChunk = (e: Event) => {
            const d = (e as CustomEvent<{ taskId: string; token: string; text: string }>).detail;
            if (d.taskId !== sseHandle.taskId) return;
            _onChunk(d.token);
          };
          window.addEventListener("agent:stream-chunk", _sseOnChunk);

          const _sseMsgId = streamingMsgIdRef.current;
          const { eventRuntime: _er } = await import("@/core/events");

          try {
            await new Promise<void>((resolve, reject) => {
              if (abort.signal.aborted) { resolve(); return; }
              let _resolved = false;
              const _done = (err?: Error) => {
                if (_resolved) return;
                _resolved = true;
                _u1?.(); _u2?.(); _u3?.();
                _unsubStore();
                if (err) reject(err);
                else resolve();
              };

              // Stop utente → risolvi (non è un errore)
              abort.signal.addEventListener("abort", () => _done(), { once: true });

              let _u1: (() => void) | undefined;
              let _u2: (() => void) | undefined;
              let _u3: (() => void) | undefined;

              _u1 = _er.on("task_complete", (ev) => {
                if (ev.taskId !== sseHandle.taskId) return;
                _done();
              });
              _u2 = _er.on("task_error", (ev) => {
                if (ev.taskId !== sseHandle.taskId) return;
                _done(abort.signal.aborted ? undefined : new Error(ev.message));
              });
              _u3 = _er.on("task_cancel", (ev) => {
                if (ev.taskId !== sseHandle.taskId) return;
                _done();
              });

              // Fallback: osserva taskStore per stati terminali (USR timeout, network drop)
              const _unsubStore = useTaskStore.subscribe((state) => {
                const _t = state.tasks.find(t => t.id === sseHandle.taskId);
                if (!_t) return;
                const _TERMINAL = ["SUCCESS", "ERROR", "TIMEOUT", "CANCELLED"];
                if (!_TERMINAL.includes(_t.status)) return;
                const _isErr = _t.status === "ERROR" || _t.status === "TIMEOUT";
                _done(_isErr ? new Error(_t.error ?? "Task terminato con errore") : undefined);
              });
            });
          } finally {
            window.removeEventListener("agent:stream-chunk", _sseOnChunk);
          }

          // Converti TaskAction[] → AgentStep[] e salva nel messaggio per display post-stream
          if (_sseMsgId) {
            const _ft = useTaskStore.getState().tasks.find(t => t.id === sseHandle.taskId);
            if (_ft?.actions.length) {
              const _steps = _ft.actions
                .filter(a => a.type !== "plan")
                .map(a => ({
                  tool:        a.toolName ?? String(a.type),
                  status:      (a.done ? "done" : "running") as "done" | "running" | "error",
                  output:      a.detail,
                  explanation: a.explanation,
                  timestamp:   a.at,
                }));
              if (_steps.length > 0) {
                setMessages(prev => (prev.map(m => m.id === _sseMsgId ? { ...m, steps: _steps } : m) as Message[]));
              }
            }
          }
          // taskStore già aggiornato a SUCCESS da agentSSEDispatch

        } else {
          // ── Local agent path (fallback: backend non disponibile / resume task) ──
          if (opts?.resumeTaskId) {
            _taskId = opts.resumeTaskId;
            ts0.retryTask(_taskId);
            ts0.updateStatus(_taskId, "RUNNING");
          } else {
            _taskId = ts0.startTask(text);
            ts0.updateStatus(_taskId, "RUNNING");
          }
          const { runAgentLoop } = await _loadAgentLoop();
          await runAgentLoop(
            "",
            buildRawMessages(msgsForLLM, _ws.openFile, _ws.settings) as Array<{ role: string; content: string }>,
            { model: _effectiveThinkMode ? "deepseek-ai/DeepSeek-R1" : _ws.settings.model, temperature: _ws.settings.temperature, maxTokens: _ws.settings.maxTokens, keepThink: _effectiveThinkMode, taskId: _taskId!, conversationId: convId },
            {
              onChunk:  _onChunk,
              onStatus: _onAgentStatus,
              onNeedConfirm: (req) => new Promise<boolean>((resolve) => {
                confirmResolverRef.current = resolve;
                setPendingConfirm(req);
              }),
              onSteps: (steps) => {
                if (!streamingMsgIdRef.current) return;
                setMessages(prev => prev.map(m => m.id === streamingMsgIdRef.current ? { ...m, steps } : m));
              },
              onSuggestions: (sugs) => setSuggestions(sugs),
            },
            abort.signal,
          );
          useTaskStore.getState().updateStatus(_taskId, "SUCCESS");
        }
      } else {
        await streamWithFallback(
          getAnyToken() || "",
          buildMessages(msgsForLLM, _ws.openFile, _ws.settings),
          _onChunk,
          abort.signal,
          { model: _effectiveThinkMode ? "deepseek-ai/DeepSeek-R1" : _ws.settings.model, temperature: _ws.settings.temperature, maxTokens: _ws.settings.maxTokens, keepThink: _effectiveThinkMode },
        );
      }

      if (_isAutoMode) { setAgentMode(false); setThinkMode(false); }
      if (rafId !== null) { cancelAnimationFrame(rafId); rafId = null; }

      if (streamingConvIdRef.current === convId) {
        const cleanContent = accumulated.replace(/\u200B/g, "");
        setMessages(prev => {
          const final = prev.map(m => m.id === assistantMsg.id ? { ...m, content: cleanContent } : m);
          _persistMsgs(convId, final);
          return final;
        });
        _setStreamContent(""); _streamMsgIdRef.current = null;
        const touched = touchConversation(currentConvs, convId);
        setConversations(touched); saveConversations(touched);

        // S264: async AI title — dopo il primo scambio
        if (withUser.length === 1) {
          void (async () => {
            try {
              const _token = getAnyToken();
              if (!_token) return;
              let _aiTitle = '';
              await streamWithFallback(
                _token,
                [
                  { role: 'system', content: 'Sei un assistente che genera titoli brevi. Rispondi SOLO con il titolo, niente altro. Massimo 5 parole, niente punteggiatura finale.' },
                  { role: 'user',   content: `Genera un titolo brevissimo (3-5 parole, in italiano) per una conversazione che inizia con: "${text.slice(0, 200)}"` },
                ],
                (chunk) => { _aiTitle += chunk; },
                new AbortController().signal,
                { model: 'llama-3.1-8b-instant', maxTokens: 20, temperature: 0.3 },
              );
              const _t = _aiTitle.replace(/^["']|["']$|^Titolo:\s*/gi, '').trim().slice(0, 54);
              if (_t.length >= 4) {
                const _convs = useConversationStore.getState().conversations;
                const _upd   = updateConversationTitle(_convs, convId, _t.charAt(0).toUpperCase() + _t.slice(1));
                setConversations(_upd); saveConversations(_upd);
              }
            } catch { /* non-fatal */ }
          })();
        }
      }
    } catch (err: unknown) {
      if (rafId !== null) { cancelAnimationFrame(rafId); rafId = null; }
      if ((err as Error)?.name === "AbortError") {
        const partial = accumulated.replace(/\u200B/g, "").trim();
        const stopped = withUser.concat({ ...assistantMsg, content: partial || "_(risposta interrotta)_" });
        setMessages(stopped);
        if (streamingConvIdRef.current === convId) _persistMsgs(convId, stopped);
        _setStreamContent(""); _streamMsgIdRef.current = null;
        return;
      }
      const rawMsg = (err as Error).message ?? "";
      if (_taskId) useTaskStore.getState().updateStatus(_taskId, "ERROR", rawMsg || "Errore sconosciuto");
      const friendlyMsg = rawMsg.includes("All providers exhausted") || rawMsg.includes("503")
        ? "⚠️ Tutti i provider AI sono temporaneamente esauriti. Riprova tra qualche minuto, oppure apri le **Impostazioni** per configurare un'API key alternativa."
        : rawMsg.includes("401") || rawMsg.includes("403")
          ? "🔑 API key non valida o scaduta. Apri le **Impostazioni** per aggiornare la chiave."
          : rawMsg.includes("429")
            ? "⏱️ Rate limit raggiunto. Attendi qualche secondo e riprova, oppure apri le **Impostazioni** per aggiungere un'API key alternativa."
            : `Errore: ${rawMsg}`;
      const errMsg = withUser.concat({ ...assistantMsg, content: friendlyMsg, error: true });
      setMessages(errMsg); _persistMsgs(convId, errMsg);
    } finally {
      import("@/lib/liveGuidanceStore").then(m => m.liveGuidanceStore.clear()).catch(() => {});
      setIsStreaming(false);
      if (typeof requestIdleCallback !== "undefined") {
        requestIdleCallback(() => {
          import("@/lib/sessionAnalyzer").then(m => m.runSessionAnalysis()).catch(() => {});
        }, { timeout: 10_000 });
      }
      abortRef.current           = null;
      streamingConvIdRef.current = null;
      streamingMsgIdRef.current  = null;
    }
  // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [_persistMsgs, setInput, setAttachedFiles, setPendingDisambig,
      setConversations, setActiveId, setMessages, setIsStreaming, setTab, setAgentLiveStatus,
      setSuggestions, setPendingConfirm, setAgentMode, setThinkMode]);

  // ── sendMessage ref sync ──────────────────────────────────────────────────
  useEffect(() => { _sendMsgRef.current = sendMessage; }, [sendMessage]);

  // ── agente-ai:send listener (GAP-C) ──────────────────────────────────────
  useEffect(() => {
    const _h = (e: Event) => {
      const text = (e as CustomEvent<{ text: string }>).detail?.text;
      if (text) { setSuggestions([]); void sendMessage(text); }
    };
    window.addEventListener("agente-ai:send", _h);
    return () => window.removeEventListener("agente-ai:send", _h);
  }, [sendMessage]);

  // ── V7-5: agente:steer listener — soft-steer hint ──────────────────────────
  useEffect(() => {
    const _steerH = (e: Event) => {
      const d = (e as CustomEvent<{ tool: string; hint: string }>).detail;
      if (!d?.hint) return;
      if (useChatStore.getState().isStreaming) {
        import("@/lib/liveGuidanceStore")
          .then(m => m.liveGuidanceStore.push(`[STEER ${d.tool}] ${d.hint}`))
          .catch(() => {});
      } else {
        _pendingSteerRef.current = d.hint;
      }
    };
    window.addEventListener("agente:steer", _steerH);
    return () => window.removeEventListener("agente:steer", _steerH);
  }, []); // eslint-disable-line react-hooks/exhaustive-deps

  // ── Session save debounced 5min ───────────────────────────────────────────
  useEffect(() => {
    if (!isStreaming && messages.length > 2) {
      const now = Date.now();
      if (now - _lastSaveRef.current > 300_000) {
        _lastSaveRef.current = now;
        saveSession(messages.map(m => ({ role: m.role, content: m.content })));
      }
      const { streamingTaskId } = useChatStore.getState();
      if (!streamingTaskId) useChatStore.getState().clearStreaming();
    }
  // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [isStreaming]);

  // ── Auto-save ogni 30s durante streaming (S258) ───────────────────────────
  useEffect(() => {
    if (!isStreaming) return;
    const id = activeId;
    if (!id) return;
    const interval = setInterval(() => {
      const { messages: liveMessages, persistMsgs: _p } = useConversationStore.getState();
      if (liveMessages.length > 0) _p(id, liveMessages);
    }, 30_000);
    return () => clearInterval(interval);
  // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [isStreaming, activeId]);

  // ── Agent live status cycling ─────────────────────────────────────────────
  useEffect(() => {
    if (!isStreaming) { agentLiveStatusRef.current = ""; setAgentLiveStatus(""); return; }
    hasFirstChunkRef.current = false;
    const push = (text: string) => {
      if (hasFirstChunkRef.current) return;
      agentLiveStatusRef.current = text;
      setAgentLiveStatus(text);
      if (streamingMsgIdRef.current)
        setMessages(prev => prev.map(m => m.id === streamingMsgIdRef.current ? { ...m, agentStatus: text } : m));
    };
    const timers = [
      setTimeout(() => push("Comprendo la richiesta..."),    0),
      setTimeout(() => push("Pianificazione risposta..."), 1400),
      setTimeout(() => push("Elaborazione contesto..."),   3800),
      setTimeout(() => push("Strutturazione output..."),   8000),
      setTimeout(() => push("Generazione risposta..."),   15000),
    ];
    return () => timers.forEach(clearTimeout);
  // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [isStreaming]);

  // ── Hydrate messages on activeId change ──────────────────────────────────
  useEffect(() => {
    if (activeId) setMessages(getMessages(activeId));
    else          setMessages([]);
  // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [activeId]);

  // ── S352/S621: Banner "riprendi task interrotto" ──────────────────────────
  useEffect(() => {
    const tasks = useTaskStore.getState().tasks;
    const interrupted = tasks.find(t =>
      (t.status === "RUNNING" || t.status === "QUEUED") &&
      Date.now() - t.startedAt < RESUME_WINDOW_MS
    );
    if (interrupted) setResumeTask({ id: interrupted.id, goal: interrupted.goal.slice(0, 80) });
  }, []); // eslint-disable-line react-hooks/exhaustive-deps

  // ── S697: Safari stream abort-on-hide ────────────────────────────────────
  useEffect(() => {
    const onStreamBg = () => {
      _isSafariAbortRef.current = true;
      setTimeout(() => {
        if (_isSafariAbortRef.current && abortRef.current) abortRef.current.abort();
      }, 8000);
    };
    const onStreamFg = () => { _isSafariAbortRef.current = false; };
    window.addEventListener('safari:stream-background', onStreamBg);
    window.addEventListener('safari:stream-foreground', onStreamFg);
    return () => {
      window.removeEventListener('safari:stream-background', onStreamBg);
      window.removeEventListener('safari:stream-foreground', onStreamFg);
    };
  }, []);

  // ── S402: reset repair guard su nuova versione HTML ───────────────────────
  useEffect(() => {
    _previewAutoRepairFired.current = false;
  }, [previewHtml?.content]);

  // ── OPFS fallback toast ───────────────────────────────────────────────────
  useEffect(() => {
    const handler = (e: Event) => {
      const path = (e as CustomEvent<{ path: string }>).detail?.path ?? "";
      toast.warning(
        `File salvato in memoria alternativa${path ? ` (${path.split("/").pop()})` : ""} — OPFS non disponibile su questo browser.`,
        { duration: 6000 },
      );
    };
    window.addEventListener("vfs:opfs-fallback", handler);
    return () => window.removeEventListener("vfs:opfs-fallback", handler);
  }, []);

  // ── handleRetry ──────────────────────────────────────────────────────────
  const handleRetry = useCallback(() => {
    const msgs    = useConversationStore.getState().messages;
    const lastIdx = msgs.length - 1;
    if (lastIdx < 1) return;
    const prev = msgs[lastIdx - 1];
    if (prev?.role === "user") {
      setMessages(m => m.slice(0, lastIdx - 1));
      void sendMessage(prev.content);
    }
  }, [sendMessage, setMessages]);

  // ── handleAutoFix ────────────────────────────────────────────────────────
  const handleAutoFix = useCallback((error: string, code: string, filename: string) =>
    void sendMessage(
      `Fix questo errore e restituisci il file completo corretto.\n\n**File:** \`${filename}\`\n**Errore:**\n\`\`\`\n${error}\n\`\`\`\n**Codice:**\n\`\`\`\n${code}\n\`\`\``
    ), [sendMessage]);

  // ── handleExport ─────────────────────────────────────────────────────────
  const handleExport = useCallback(() => {
    const { conversations, activeId: aid, messages: msgs } = useConversationStore.getState();
    const conv = conversations.find(c => c.id === aid);
    if (!conv) return;
    exportAsJSON(conv, msgs);
  }, []);

  // ── handleImport ─────────────────────────────────────────────────────────
  const handleImport = useCallback(() => { importFileRef.current?.click(); }, []);

  // ── handleImportFile ─────────────────────────────────────────────────────
  const handleImportFile = useCallback(async (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0];
    if (!file) return;
    e.target.value = "";
    try {
      const { conv, messages: msgs } = await importFromJSON(file);
      const convs = [conv, ...getConversations()];
      saveConversations(convs); saveMessages(conv.id, msgs);
      setConversations(convs); setActiveId(conv.id); setMessages(msgs);
      try { sessionStorage.setItem("agente_active_id", conv.id); } catch { /**/ }
    } catch (err) {
      addAlert({ severity: "error", title: "Import fallito", message: String(err instanceof Error ? err.message : err), source: "import" });
    }
  }, [setConversations, setActiveId, setMessages, addAlert]);

  // ── handlePreviewRuntimeError (S402) ─────────────────────────────────────
  const handlePreviewRuntimeError = useCallback((errors: PreviewRuntimeError[]) => {
    if (_previewAutoRepairFired.current) return;
    const _cs = useChatStore.getState();
    if (_cs.isStreaming) return;
    _previewAutoRepairFired.current = true;
    const _pHtml = useWorkspaceStore.getState().previewHtml;
    if (_pHtml?.name) {
      const _firstErr = errors[0]?.message ?? "errore runtime";
      import("@/lib/projectStateGraph").then(m => m.markFailed(_pHtml.name!, _firstErr)).catch(() => {});
    }
    const errorLines = errors.slice(0, 3)
      .map((e, i) => `${i + 1}. ${e.message}${e.line ? ` (riga ${e.line})` : ""}`)
      .join("\n");
    void sendMessage(
      `🔴 **Errore runtime rilevato nel preview HTML** (auto-repair S402)\n\n\`\`\`\n${errorLines}\n\`\`\`\n\nCorreggi il file HTML/JS nel VFS e riscrivilo completo. Non spiegare — scrivi direttamente il codice corretto.`,
    );
  }, [sendMessage]);

  // ── handlePreviewVerified (S403) ─────────────────────────────────────────
  const handlePreviewVerified = useCallback(() => {
    const _pHtml = useWorkspaceStore.getState().previewHtml;
    if (_pHtml?.name)
      import("@/lib/projectStateGraph").then(m => m.markVerified(_pHtml.name!)).catch(() => {});
  }, []);

  // ── handleRunRequest ──────────────────────────────────────────────────────
  const handleRunRequest = useCallback((code: string, filename: string) => {
    setRunCode({ code, filename });
    setTab("chat");
    const ext = filename.split(".").pop()?.toLowerCase() ?? "";
    if (ext === "py") {
      void sendMessage(`Esegui questo script Python:\n\`\`\`python\n${code}\n\`\`\``);
    } else if (ext === "js" || ext === "ts" || ext === "mjs") {
      void sendMessage(`Esegui questo codice:\n\`\`\`${ext}\n${code}\n\`\`\``);
    } else {
      setTab("run");
    }
  }, [sendMessage, setRunCode, setTab]);

  return {
    streamingContent: _streamContent,
    streamingMsgIdRef: _streamMsgIdRef,
    suggestions, setSuggestions,
    resumeTask, setResumeTask,
    pendingConfirm, setPendingConfirm,
    confirmResolverRef,
    abortRef, importFileRef,
    sendMessage, handleRetry, handleAutoFix,
    handleExport, handleImport, handleImportFile,
    handlePreviewRuntimeError, handlePreviewVerified,
    handleRunRequest, executeSlashCommand,
  };
}