src/lib/agentLoop/case2Block.ts

/**
 * case2Block.ts — S504: extracted from agentLoop.ts
 *
 * Gestisce il Case 2 completo: text-based ReAct actions (HF/text models).
 * Pipeline:
 *   1. Stripping blocchi <think>…</think> da rawText → cleanRawText
 *   2. Parse textActions da cleanRawText
 *   3. Se textActions.length > 0 && iter < MAX_ITER-1:
 *      - Esecuzione sequenziale tool con CB + stall detection
 *      - Error recovery, live debug fix, belief revision, exec-reinject tracking
 *      - Stagnation guard (3 iters consecutive fallite → return)
 *      → action "continue"
 *   4. Altrimenti: action "skip" (il caller processa Case 3 con cleanRawText)
 *
 * Muta steps e loopMessages per reference.
 * Restituisce cleanRawText sempre (usato da Case 3 per candidateText).
 *
 * @module case2Block
 */

import type { AgentStep } from "../storage";
import { narrativeLabel } from "./toolStatusLabels"; // S766
import { parseTextActions } from "./intentParser";
import { _tryLiveDebugFix } from "./toolExecutor";
import { verifyToolResult, annotateWithProof } from "../agent/verifier";
import { updateWorldModel } from "../worldModel";
import { selfLearning } from "../selfLearning";
import { recordErrorAsync } from "../selfLearningAsync"; // S649
import { errorLog } from "../agentBrain";
import { recordAndSuggestFix, notifyToolSuccess } from "../agent/errorRecovery";
import { persistBeliefState, handleToolFailureBelief, shouldReviseBeliefs, buildRevisionPrompt } from "../beliefRevision";
import { predictOutcome, shouldReviseImmediately } from "./actionSimulator"; // S-PRED
import { EXEC_REINJECT_TOOLS } from "./toolGate";
import { infraCategory } from "./stallDetector"; // P32-GE-1
import { buildExecReinjectMessage } from "./execLoopGate";
import type { ApiMsg } from "./networkTools";

// ─── Interfaces ────────────────────────────────────────────────────────────────

export interface Case2BlockCtx {
  rawText: string;
  iter: number;
  MAX_ITER: number;
  // Mutable state (returned updated)
  steps: AgentStep[];
  loopMessages: ApiMsg[];
  consecutiveAllFailIters: number;
  effectiveMaxIter: number;
  sessStats: { autoFixed: number; propagated: number; verifyFails: number };
  lastExecTool: string;
  lastExecOutput: string;
  lastExecResultIter: number;
  // Read-only context
  lastUserMsg: string;
  loopTaskId: string | null;
  route: string;
  routeStart: number;
  taskPlan: unknown;
  preCls: { type: string } | null;
  // Callbacks
  onStatus: (msg: string) => void;
  onSteps: (steps: AgentStep[]) => void;
  onChunk: (chunk: string) => void;
  // Closures
  executeToolGated: (name: string, args: unknown) => Promise<string>;
  epistemicTag: (toolName: string) => string;
  cbIsOpen: (name: string, iter: number) => boolean;
  cbUpdate: (name: string, result: string, iter: number) => void;
  cbSkipMsg: (name: string) => string;
  stallCheck: (name: string, args: Record<string, unknown>) => number;
  writeSess: () => void;
  recordTaskOutcome: (type: string, outcome: string) => void;
  onRouteRecord: (success: boolean) => void;
}

export type Case2BlockAction = "continue" | "return" | "skip";

export interface Case2BlockResult {
  action: Case2BlockAction;
  cleanRawText: string;
  consecutiveAllFailIters: number;
  effectiveMaxIter: number;
  sessStats: { autoFixed: number; propagated: number; verifyFails: number };
  lastExecTool: string;
  lastExecOutput: string;
  lastExecResultIter: number;
}

// ─── Main export ───────────────────────────────────────────────────────────────

/** Processa il Case 2 (ReAct text actions). Ritorna "skip" se non ci sono azioni → il caller processa Case 3. */
export async function processCase2Block(ctx: Case2BlockCtx): Promise<Case2BlockResult> {
  const {
    rawText, iter, MAX_ITER, lastUserMsg, loopTaskId, route: _route, routeStart: _routeStart, taskPlan: _taskPlan, preCls,
    onStatus, onSteps, onChunk, executeToolGated, epistemicTag, cbIsOpen, cbUpdate, cbSkipMsg,
    stallCheck, writeSess, recordTaskOutcome, onRouteRecord,
  } = ctx;

  const steps      = ctx.steps;
  const loopMessages = ctx.loopMessages;
  let consecutiveAllFailIters = ctx.consecutiveAllFailIters;
  let effectiveMaxIter        = ctx.effectiveMaxIter;
  const sessStats             = { ...ctx.sessStats };
  let lastExecTool            = ctx.lastExecTool;
  let lastExecOutput          = ctx.lastExecOutput;
  let lastExecResultIter      = ctx.lastExecResultIter;

  // ── 1. Stripping <think>…</think> + parse textActions ─────────────────────
  // S188: estrai + rimuovi tutti i blocchi <think> (ovunque, non solo in testa)
  const _thinkBlocks  = rawText.match(/<think>([\s\S]*?)<\/think>/gi) ?? [];
  const _thinkContent = _thinkBlocks.map(b => b.replace(/<\/?think>/gi, "").trim()).filter(t => t.length > 50).join("\n\n");
  // S188+S189: strip blocchi chiusi + blocco aperto/incompleto (finish_reason=length)
  const cleanRawText = rawText.replace(/<think>[\s\S]*?<\/think>/gi, "").replace(/<think>[\s\S]*/gi, "").trim();

  if (_thinkContent.length > 50 && !steps.some(s => s.tool === "__thinking__")) {
    const thinkStep: AgentStep = { tool: "__thinking__", args: {}, result: _thinkContent, status: "done" };
    steps.push(thinkStep); onSteps([...steps]);
  }
  const textActions = parseTextActions(cleanRawText);

  // ── 2. Guard: solo se ci sono azioni e siamo prima dell'ultima iter ─────────
  if (!(textActions.length > 0 && iter < MAX_ITER - 1)) {
    return { action: "skip", cleanRawText, consecutiveAllFailIters, effectiveMaxIter, sessStats, lastExecTool, lastExecOutput, lastExecResultIter };
  }

  // ── 3. Esecuzione sequenziale tool ────────────────────────────────────────
  // Show reasoning text (stripped of action tags) as status
  const thinkingText = rawText.replace(/<action>[\s\S]*?<\/input>/gi, "").trim();
  if (thinkingText.length > 10) onStatus(thinkingText.slice(0, 120) + (thinkingText.length > 120 ? "…" : ""));

  loopMessages.push({ role: "assistant", content: rawText } as ApiMsg);

  let _beliefRevisionDoneThisIter = false; // S-GAP2a guard: al massimo 1 revisione per iterazione
  for (const ta of textActions) {
    // S766: label contestuale invece del tipo tool generico
    onStatus(narrativeLabel(ta.name, ta.args as Record<string, unknown>));
    // S766: context-aware explanation field
    const step: AgentStep = { tool: ta.name, args: ta.args, result: "", status: "running", explanation: narrativeLabel(ta.name, ta.args as Record<string, unknown>) };
    steps.push(step);
    onSteps([...steps]);

    // S-PRED: pre-esecuzione prediction — avvisa su tool rischiosi con precedenti non risolti
    const _pred = (() => {
      try { return predictOutcome(ta.name, ta.args as Record<string, unknown>, errorLog.recent(50)); }
      catch { return null; }
    })();
    if (_pred?.predictedOutcome === "likely_fail") {
      onStatus(`⚠️ Predizione rischio: ${_pred.reason}`);
      loopMessages.push({
        role: "user",
        content: `[PRE-EXECUTION WARNING] ${_pred.reason}. Valuta un approccio alternativo prima di procedere con "${ta.name}".`,
      } as ApiMsg);
    }

    // Circuit breaker + stall detection
    const _c2StallN = stallCheck(ta.name, ta.args as Record<string, unknown>);
    // S444: hint cross-sessione per messaggio stallo ReAct
    const _c2ErrHint = _c2StallN >= 3 ? (() => {
      try {
        const _wf = errorLog.resolvedWithFix().find(e => e.context.includes(ta.name));
        return _wf ? `\n💡 Fix noto (${_wf.count}× visto): ${_wf.fix!.slice(0, 200)}` : "";
      } catch { return ""; }
    })() : "";
    const result: string = _c2StallN >= 3
      ? `❌ Stallo rilevato — "${ta.name}" chiamato ${_c2StallN}× con gli stessi argomenti. Cambia approccio o scrivi DONE: se il task è completato.${_c2ErrHint}`
      : cbIsOpen(ta.name, iter)
      ? cbSkipMsg(ta.name)
      : await (executeToolGated(ta.name, ta.args) as Promise<string>)
          .then(r => { cbUpdate(ta.name, r, iter); return r; });
    step.result = result;
    step.status = result.startsWith("❌") ? "error" : "done";
    onSteps([...steps]);

    let _reactRecovery: ReturnType<typeof recordAndSuggestFix> | null = null;

    if (result.startsWith("❌")) {
      // S444: registra su errorLog per hint cross-sessione (ReAct path)
      try { errorLog.record(result.slice(0, 300), `tool:${ta.name}`, undefined, (typeof ta.args === "object" && ta.args !== null && "code" in ta.args) ? String((ta.args as Record<string, unknown>).code).slice(0, 500) : undefined); } catch { /* non-blocking */ }
      // S204 GAP1: deriva fix dall'alternativa nota
      const _g1bfix = (() => {
        try { const _a = selfLearning.getAlternative(ta.name, result.slice(0, 80)); return _a ? `Usa ${_a.tool}: ${_a.hint.slice(0, 200)}` : ""; } catch { return ""; }
      })();
      recordErrorAsync(result, `tool:${ta.name}`, _g1bfix); // S649
      // S103/S351: belief revision ReAct path — S495: extracted to beliefRevision.ts
      handleToolFailureBelief({ taskId: loopTaskId ?? "", lastUserMsg, toolName: ta.name, errorResult: result, iter, path: "ReAct", loopMessages, steps, onSteps, onStatus });
      // S-PRED: se la predizione era "likely_fail" e l'esito reale è errore → revisione immediata
      if (_pred && shouldReviseImmediately(_pred, true) && !_beliefRevisionDoneThisIter) {
        onStatus("⚠️ Predizione confermata — revisione strategia immediata");
      }
      try { persistBeliefState(loopTaskId ?? "", lastUserMsg.slice(0, 40)); } catch { /* non-blocking */ } // S351: persist dopo Case 2 belief revision
      // S-GAP2a: belief revision narrative — rende visibile il cambio di strategia
      try {
        if (!_beliefRevisionDoneThisIter && shouldReviseBeliefs(loopTaskId ?? "")) {
          const _br = buildRevisionPrompt(loopTaskId ?? "", lastUserMsg);
          if (_br.shouldRevise) {
            const _cats = _br.distinctErrorCategories;
            let _narrativeMsg = "Sto ripensando l’approccio al task";
            if (_cats.includes("format_error"))    _narrativeMsg = "Formato incompatibile — rianalizzando il task da zero";
            else if (_cats.includes("not_found"))  _narrativeMsg = "Risorse non trovate — ridefinendo la strategia";
            else if (_cats.includes("logic_error")) _narrativeMsg = "Errore logico identificato — riparto dall’analisi";
            else if (_cats.includes("network_error")) _narrativeMsg = "Problema connessione — cambio approccio";
            onStatus(_narrativeMsg);
            // Emetti uno step visibile con explanation per AgentNarration / AgentStepCards
            steps.push({
              tool:        "__belief_revision__",
              args:        { categories: _cats },
              result:      `Revisione attivata: ${_cats.join(", ")}`,
              status:      "done",
              explanation: _narrativeMsg,
              durationMs:  0,
            } as AgentStep);
            _beliefRevisionDoneThisIter = true;
            onSteps([...steps]);
            loopMessages.push({ role: "user", content: _br.revisionPrompt } as ApiMsg);
          }
        }
      } catch { /* non-blocking */ }
      try { _reactRecovery = recordAndSuggestFix({ toolName: ta.name, errorMsg: result }); } catch { /* non-blocking */ }
      // S59: live debug-fix per code execution tools
      const _reactFixed = await _tryLiveDebugFix(ta.name, ta.args as Record<string, unknown>, result, `react${iter}`, onStatus);
      if (_reactFixed) {
        // S204+: registra fix immediatamente anche nel ReAct path
        try {
          recordErrorAsync(result.slice(0, 100), `livefix:react:${ta.name}`, _reactFixed.slice(0, 250)); // S649
        } catch { /* non-blocking */ }
        // S444: marca errorLog come risolto (ReAct path, cross-sessione)
        try { errorLog.markFixed(errorLog.hashOf(result.slice(0, 300)), _reactFixed.slice(0, 500)); } catch { /* non-blocking */ }
        step.result = _reactFixed; step.status = "done";
        sessStats.autoFixed++; // S205: error resolved autonomously (ReAct)
        // Fix 8 (S421): extra iteration in repair intensivo
        if (sessStats.autoFixed >= 2 && effectiveMaxIter < MAX_ITER) {
          effectiveMaxIter = Math.min(effectiveMaxIter + 1, MAX_ITER);
        }
      } else {
        sessStats.propagated++; // S205: error reaches model unchanged (ReAct)
      }
    }
    // S83: track exec result for loop closure (Case 2 - ReAct)
    if (EXEC_REINJECT_TOOLS.has(ta.name)) {
      lastExecResultIter = iter;
      lastExecOutput     = (step.result || result).slice(0, 1000);
      lastExecTool       = ta.name;
      loopMessages.push({ role: "user", content: buildExecReinjectMessage(lastExecTool, lastExecOutput) } as ApiMsg);
    }
    if (!result.startsWith("❌")) {
      try { notifyToolSuccess(ta.name); } catch { /* non-blocking */ }
    }

    // Annotate with verifier proof + epistemic tag prima di inviare al modello
    const _tvr = verifyToolResult(ta.name, ta.args as Record<string, unknown>, result);
    const _tannotated = annotateWithProof(ta.name, result, _tvr);
    const _reactFixHint = _reactRecovery?.hadFix
      ? `\n💡 Fix noto (${_reactRecovery.count}x): ${_reactRecovery.fix}`
      : (_reactRecovery?.hint ? `\n⚡ ${_reactRecovery.hint}` : "");
    // Step2: epistemic tag su OBSERVATION; Step5: update world model
    const _epTag2 = epistemicTag(ta.name);
    loopMessages.push({ role: "user", content: `OBSERVATION [${ta.name}|${_epTag2}]:\n${_tannotated}${_reactFixHint}` } as ApiMsg);
    updateWorldModel(ta.name, ta.args as Record<string, unknown>, step.result || result).catch(() => {});
  }

  // ── 4. Stagnation guard ────────────────────────────────────────────────────
  {
    const _c2StartIdx  = Math.max(0, steps.length - textActions.length);
    const _c2AllFailed = steps.slice(_c2StartIdx).every(s => s.status === "error");
    consecutiveAllFailIters = (textActions.length > 0 && _c2AllFailed) ? consecutiveAllFailIters + 1 : 0;
    if (consecutiveAllFailIters >= 3) {
      onChunk("_(Stagnazione rilevata: " + consecutiveAllFailIters + " iterazioni consecutive con tutti i tool falliti. Interrompo il loop. Prova a riformulare il task o cambia provider.)_");
      try { recordTaskOutcome(preCls?.type ?? "unknown", "failure"); } catch { /* non-blocking */ }
      onRouteRecord(false);
      writeSess(); // S205
      return { action: "return", cleanRawText, consecutiveAllFailIters, effectiveMaxIter, sessStats, lastExecTool, lastExecOutput, lastExecResultIter };
    }
  }


  // ── P32-GE-1: Infra error graceful exit (ReAct path) ─────────────────────
  // Scansiona le OBSERVATION messages recenti: ≥3 errori infra consecutivi
  // della stessa categoria → exit onesto prima che il loop si inceppi.
  {
    const _c2ObsMsgs = (loopMessages as Array<{ role: string; content?: unknown }>)
      .filter(m => m.role === "user" && typeof m.content === "string" &&
                   (m.content as string).startsWith("OBSERVATION"))
      .slice(-9); // ultime 9 osservazioni ReAct
    let _c2InfraCount = 0;
    let _c2InfraCat: string | null = null;
    for (let _i = _c2ObsMsgs.length - 1; _i >= 0; _i--) {
      const _obs = _c2ObsMsgs[_i].content as string;
      const _obsContent = _obs.slice(_obs.indexOf(":\n") + 3).trimStart();
      if (!_obsContent.startsWith("❌")) break;
      const _cat = infraCategory(_obsContent);
      if (_cat === null) break;
      if (_c2InfraCat === null) _c2InfraCat = _cat;
      if (_cat !== _c2InfraCat) break;
      _c2InfraCount++;
    }
    if (_c2InfraCount >= 3 && _c2InfraCat) {
      const _infraMsgMap2: Record<string, string> = {
        rate_limit:   "Il provider è in rate limit (429) ripetuto",
        timeout:      "Timeout ripetuto dal provider o backend",
        server_5xx:   "Errore server 5xx ripetuto dal backend",
        network_fail: "Errore di rete persistente",
      };
      const _infraLabel2 = _infraMsgMap2[_c2InfraCat] ?? "Errore infrastrutturale ripetuto";
      onChunk(`_(${_infraLabel2} — rilevato ${_c2InfraCount}× di seguito. Il servizio è temporaneamente non disponibile. Riprova tra qualche minuto o cambia provider nelle impostazioni.)_`);
      try { recordTaskOutcome(preCls?.type ?? "unknown", "failure"); } catch { /* non-blocking */ }
      onRouteRecord(false);
      writeSess();
      return { action: "return", cleanRawText, consecutiveAllFailIters, effectiveMaxIter, sessStats, lastExecTool, lastExecOutput, lastExecResultIter };
    }
  }

  return { action: "continue", cleanRawText, consecutiveAllFailIters, effectiveMaxIter, sessStats, lastExecTool, lastExecOutput, lastExecResultIter };
}