"use client";

import React, { useState, useRef, useEffect, useMemo } from "react";
import DiagnosticsView from "@/components/diagnostics-view";
import GraphUpdateView from "@/components/graph-update-view";
import SituationGraphView from "@/components/situation-graph-view";
import InvestigationSummaryPanel from "@/components/investigation-summary-panel";
import InvestigationSummaryPanelV2 from "@/components/investigation-summary-panel-v2";
import InvestigationSummaryPanelV3 from "@/components/investigation-summary-panel-v3";
import InvestigationMap from "@/components/investigation-map";

// ── Technical summary detector (main view filters these) ───
const TECHNICAL_PATTERNS = [
  /nodes?\s*[:\d]/i,
  /edges?\s*[:\d]/i,
  /\b(?:unknown|observation|conclusion)\b\s/i,
  /\bsorted\b/i,
  /by_kind/i,
  /\b(?:node|edge|unknown|state)\s+count/i,
];

function isTechnicalSummary(summary) {
  if (!summary || typeof summary !== "string") return false;
  const trimmed = summary.trim();
  if (!trimmed) return false;
  for (const p of TECHNICAL_PATTERNS) {
    if (p.test(trimmed)) return true;
  }
  return false;
}

// ── Recovery state components (Phase 2) ───────────────────────

function ProviderUnavailableCard({ onRestart }) {
  return (
    <div className="rounded-lg border border-amber-300 bg-amber-50 px-5 py-6 text-center">
      <h2 className="mb-1 text-sm font-bold uppercase tracking-wide text-amber-700">Provider unavailable</h2>
      <p className="text-sm text-amber-800 mb-4">
        The reasoning service could not be reached. This is usually temporary — check that the local model is running and try again.
      </p>
      {onRestart && (
        <button
          onClick={onRestart}
          className="rounded-lg border border-amber-300 bg-white px-4 py-2 text-sm font-medium text-amber-800 hover:bg-amber-100"
        >
          Restart investigation
        </button>
      )}
    </div>
  );
}

function MalformedResponseCard({ onRestart }) {
  return (
    <div className="rounded-lg border border-orange-300 bg-orange-50 px-5 py-6 text-center">
      <h2 className="mb-1 text-sm font-bold uppercase tracking-wide text-orange-700">Unexpected response</h2>
      <p className="text-sm text-orange-800 mb-4">
        The reasoning service returned a response we could not interpret. This may indicate a temporary issue with the model output format.
      </p>
      {onRestart && (
        <button
          onClick={onRestart}
          className="rounded-lg border border-orange-300 bg-white px-4 py-2 text-sm font-medium text-orange-800 hover:bg-orange-100"
        >
          Try again
        </button>
      )}
    </div>
  );
}

function UnexpectedStateCard({ stateName, onRetry, onRestart }) {
  return (
    <div className="rounded-lg border border-red-300 bg-red-50 px-5 py-6 text-center">
      <h2 className="mb-1 text-sm font-bold uppercase tracking-wide text-red-700">Unexpected state</h2>
      <p className="text-sm text-red-800 mb-4">
        {stateName ? `The system is in an unexpected state (${stateName}).` : "An unexpected internal error occurred."}
        Please restart the investigation to continue.
      </p>
      <div className="flex items-center justify-center gap-3">
        {onRetry && (
          <button
            onClick={onRetry}
            className="rounded-lg border border-red-300 bg-white px-4 py-2 text-sm font-medium text-red-800 hover:bg-red-100"
          >
            Retry update
          </button>
        )}
        {onRestart && (
          <button
            onClick={onRestart}
            className="rounded-lg bg-red-700 px-4 py-2 text-sm font-medium text-white hover:bg-red-600"
          >
            Restart investigation
          </button>
        )}
      </div>
    </div>
  );
}

function ContinueLaterBanner({ onRestart }) {
  return (
    <div className="rounded-lg border border-blue-200/60 bg-blue-50/40 px-5 py-4 text-center">
      <p className="text-sm text-blue-700/70">
        Your previous investigation state is still saved. You can continue where you left off or start fresh.
      </p>
      {onRestart && (
        <button
          onClick={onRestart}
          className="mt-2 text-sm font-medium text-blue-700 underline hover:text-blue-900"
        >
          Restart investigation
        </button>
      )}
    </div>
  );
}

// ── Session persistence hook (Phase 3) ────────────────────────

function useSessionPersistence() {
  const [sessionReady, setSessionReady] = useState(false);
  const sessionKey = "confidence-engine-session";

  function saveSession(state) {
    if (typeof sessionStorage === "undefined") return;
    try {
      sessionStorage.setItem(sessionKey, JSON.stringify(state));
    } catch (_) { /* quota or disabled — ignore silently */ }
  }

  function loadSession() {
    if (typeof sessionStorage === "undefined") return null;
    try {
      const raw = sessionStorage.getItem(sessionKey);
      return raw ? JSON.parse(raw) : null;
    } catch (_) {
      return null;
    }
  }

  function clearSession() {
    if (typeof sessionStorage === "undefined") return;
    try { sessionStorage.removeItem(sessionKey); } catch (_) {}
  }

  return { saveSession, loadSession, clearSession, sessionReady: true };
}

// ── Current understanding card ────────────────────────────────

// Evidence-limit text that must not appear inside Current understanding
// when the terminal outcome already communicates that state.
const EVIDENCE_LIMIT_PHRASES = [
  "The available evidence has reached its current limit",
  "evidence has reached its current limit",
  "evidence limit reached",
  "has reached its current limit",
];

function resolveCurrentSummary(currentSummary) {
  if (!currentSummary || typeof currentSummary !== "string") return null;
  const trimmed = currentSummary.trim();
  if (!trimmed) return null;

  // Filter out technical graph summaries
  for (const p of TECHNICAL_PATTERNS) {
    if (p.test(trimmed)) return null;
  }

  // Don't show evidence-limit text in Current understanding when
  // the terminal outcome card already communicates that state.
  const lower = trimmed.toLowerCase();
  for (const phrase of EVIDENCE_LIMIT_PHRASES) {
    if (lower.includes(phrase)) return null;
  }

  return trimmed;
}

// ── Status message pools for loading feedback ────────────────
const INITIAL_MESSAGES = [
  { min: 0, text: "Reading your situation" },
  { min: 10, text: "Building a structured understanding" },
  { min: 25, text: "Identifying what is known and still unclear" },
  { min: 45, text: "Selecting the next useful question" },
];

const UPDATE_MESSAGES = [
  { min: 0, text: "Considering your answer" },
  { min: 10, text: "Updating the situation" },
  { min: 25, text: "Checking what changed" },
  { min: 45, text: "Choosing the next question" },
];

function useLoadingStatus(messages, isLoading) {
  const [elapsed, setElapsed] = useState(0);
  const startRef = useRef(null);

  useEffect(() => {
    if (isLoading) {
      startRef.current = Date.now();
      const iv = setInterval(() => {
        setElapsed(Math.floor((Date.now() - startRef.current) / 1000));
      }, 1000);
      return () => clearInterval(iv);
    } else {
      setElapsed(0);
      startRef.current = null;
    }
  }, [isLoading]);

  const currentMessage = useMemo(() => {
    if (!messages || messages.length === 0) return "";
    let msg = messages[0].text;
    for (const m of messages) {
      if (elapsed >= m.min) msg = m.text;
    }
    return msg;
  }, [messages, elapsed]);

  return { elapsed, currentMessage };
}

// ── Spinner component ───────────────────────────────────────
function ActivitySpinner() {
  return (
    <span
      className="inline-block h-4 w-4 border-[2px] border-gray-300 border-t-gray-600 rounded-full"
      style={{ animation: "spin 1s linear infinite" }}
    />
  );
}

// ── Current investigation card (prominent hero section) ──────
function CurrentInvestigationCard({ selectedQuestion, graph }) {
  if (!selectedQuestion) return null;

  const q = typeof selectedQuestion === "string" ? selectedQuestion : selectedQuestion.question;
  if (!q) return null;

  // Derive meaningful context from the active node only when it adds value
  let whyMattersText = null;
  if (graph?.activeUnknownNodeId && graph.nodes) {
    const activeNode = graph.nodes.find((n) => n.id === graph.activeUnknownNodeId);
    if (activeNode?.description && activeNode.description !== activeNode.label) {
      whyMattersText = activeNode.description;
    }
  }

  return (
    <div className="investigation-card rounded-lg border-[2.5px] border-green-400 bg-gradient-to-b from-green-50 to-white p-8 shadow-sm">
      <h2 className="mb-3 text-xs font-bold tracking-widest uppercase text-green-600/70">
        Investigation
      </h2>
      <p className="text-2xl font-semibold leading-tight text-gray-900">{q}</p>
      {whyMattersText && (
        <p className="mt-5 text-sm leading-relaxed text-green-800/80">
          {whyMattersText}
        </p>
      )}
    </div>
  );
}

// ── Outcome helpers ───────────────────────────────────────────

function hasGenuineCompletion(graph) {
  if (!graph || !graph.nodes?.length) return false;
  const resolvedIds = new Set(graph.resolvedNodeIds || []);
  const unresolvedCount = graph.nodes.filter(
    (n) => n.kind === "unknown" && n.status !== "resolved" && !resolvedIds.has(n.id),
  ).length;
  if (unresolvedCount > 0) return false;
  if (graph.activeUnknownNodeId) {
    const active = graph.nodes.find((n) => n.id === graph.activeUnknownNodeId);
    if (active && active.status !== "resolved" && !resolvedIds.has(active.id)) return false;
  }
  return true;
}

// ── Completion card (terminal state when all unknowns resolved) ─
function CompletionCard({ summary }) {
  return (
    <div className="rounded-lg border border-green-300 bg-green-50 px-5 py-6 text-center">
      <h2 className="mb-1 text-sm font-bold uppercase tracking-wide text-green-700">Investigation complete</h2>
      <p className="text-base text-gray-800 mb-3">The available evidence supports the following understanding.</p>
      {summary && (
        <div className="mt-4 text-left rounded-md bg-white/60 px-4 py-3 border border-green-100">
          <p className="text-sm leading-relaxed text-gray-700">{summary}</p>
        </div>
      )}
    </div>
  );
}

// ── Evidence-limit card (terminal state: no next question) ───────
function EvidenceLimitCard({ summary }) {
  return (
    <div className="rounded-lg border border-gray-200 bg-gray-50 px-5 py-6 text-center">
      <h2 className="mb-1 text-sm font-bold uppercase tracking-wide text-gray-500">Current evidence limit reached</h2>
      {summary && (
        <div className="mt-4 text-left rounded-md bg-white/60 px-4 py-3 border border-gray-100">
          <p className="text-sm leading-relaxed text-gray-700">{summary}</p>
        </div>
      )}
      <p className="mt-3 text-base text-gray-700">Further progress requires additional evidence.</p>
    </div>
  );
}

// ── Quiet facilitator state (experiment mode) ─────────────────────

function QuietStateCard() {
  return (
    <div className="rounded-lg border border-gray-200/60 bg-gray-50/40 px-5 py-5 text-center">
      <p className="text-sm leading-relaxed text-gray-500 mb-1">
        Nothing more to add here right now
      </p>
      <p className="text-xs leading-relaxed text-gray-400">
        You can continue with another question, switch branches, or return when
        you have more information.
      </p>
    </div>
  );
}

// ── New connection / late-result indicator ────────────────────────

function UpdatedConnectionCard({ update }) {
  return (
    <div className="space-y-2">
      <h2 className="text-[11px] font-semibold tracking-widest uppercase text-gray-500">
        New update
      </h2>
      <div className="rounded-lg border border-blue-200/60 bg-blue-50/40 px-4 py-3">
        <p className="text-sm leading-relaxed text-blue-800/80">{update.text}</p>
      </div>
    </div>
  );
}

// ── Branch notebook content (RTO.27A) ────────────────────────────
// Smallest useful branch-scoped composition from fixture data.
// Only renders sections grounded in existing records.

function BranchNotebookContent({
  branchContext,
  contributions,
  openQuestions,
  lateResults,
  inactiveBranchNewResults,
  doneForNowBranchIds,
  onDoneForNow,
  branchId,
}) {
  const hasOpenItems = openQuestions && openQuestions.length > 0;
  const hasContributions = contributions && contributions.length > 0;
  const isPaused = doneForNowBranchIds?.includes(branchId) || false;
  const isBranchActive = !isPaused;

  return (
    <div className="space-y-6">
      {/* Why this branch exists — origin question is primary */}
      {branchContext && (
        <div className="rounded-lg border border-blue-200/60 bg-blue-50/40 px-5 py-4">
          <h2 className="mb-1 text-[11px] font-semibold tracking-widest uppercase text-gray-500">
            Investigating
          </h2>
          {branchContext.originQuestion ? (
            <>
              <p className="text-base leading-relaxed text-gray-900">{branchContext.originQuestion.text}</p>
              {branchContext.label && branchContext.originQuestion.text !== branchContext.label && (
                <p className="mt-2 text-xs text-gray-500/70">Branch: {branchContext.label}</p>
              )}
            </>
          ) : branchContext.origin ? (
            <>
              <p className="text-base font-medium leading-tight text-gray-900">{branchContext.label}</p>
              <p className="mt-2 text-sm leading-relaxed text-gray-600">
                Trying to understand: {branchContext.origin}
              </p>
            </>
          ) : (
            <p className="text-base font-medium leading-tight text-gray-900">{branchContext.label}</p>
          )}
        </div>
      )}

      {/* What we know here */}
      {hasContributions && (
        <div className="space-y-2">
          <h2 className="text-[11px] font-semibold tracking-widest uppercase text-gray-500">
            What we know here
          </h2>
          <div className="space-y-2">
            {contributions.map((c, i) => (
              <div key={i} className="rounded-lg border border-gray-200/80 bg-gray-50/60 px-4 py-3">
                <p className="text-sm leading-relaxed text-gray-700">{c.text}</p>
              </div>
            ))}
          </div>
        </div>
      )}

      {/* Still uncertain here */}
      {hasOpenItems && (
        <div className="space-y-2">
          <h2 className="text-[11px] font-semibold tracking-widest uppercase text-gray-500">
            Still uncertain / open questions
          </h2>
          <div className="space-y-1">
            {openQuestions.map((q, i) => (
              <QuestionRow key={q.id} question={q} />
            ))}
          </div>
        </div>
      )}

      {/* New connection / updates (active branch) */}
      {lateResults && lateResults.length > 0 && (
        <UpdatedConnectionCard update={lateResults[0]} />
      )}

      {/* Done for now control — only when branch is not already paused */}
      {isBranchActive && onDoneForNow && contributions.length > 0 && (
        <div className="flex justify-end pt-1">
          <button
            onClick={(e) => { e.stopPropagation(); onDoneForNow(); }}
            style={{ cursor: "pointer" }}
            className="rounded-lg border border-gray-300 bg-white px-4 py-2 text-sm font-medium text-gray-600 hover:bg-gray-50 transition whitespace-nowrap"
          >
            Done for now
          </button>
        </div>
      )}

      {/* Quiet state */}
      {!hasOpenItems && !lateResults?.length && (
        <div className="rounded-lg border border-gray-200/60 bg-gray-50/40 px-5 py-5 text-center">
          {isPaused ? (
            <>
              <p className="text-sm leading-relaxed text-gray-500 mb-1">
                Nothing more to add here right now
              </p>
              <p className="text-xs leading-relaxed text-gray-400">
                This branch is paused. Reasoning preserved — return when you have more information.
              </p>
            </>
          ) : (
            <QuietStateCard />
          )}
        </div>
      )}
    </div>
  );
}

// ── Question row (renders clickable card with optional focused content) ─

function QuestionRow({ question }) {
  const [isFocused, setIsFocused] = useState(false);

  if (!isFocused) {
    return (
      <button
        onClick={() => setIsFocused(true)}
        style={{ cursor: "pointer" }}
        className="w-full text-left rounded-lg border border-gray-200 px-4 py-3 transition hover:border-gray-300 hover:bg-white"
      >
        <p className="text-sm leading-snug text-gray-600">{question.label}</p>
      </button>
    );
  }

  return (
    <div className="rounded-lg border border-gray-200 bg-white px-4 py-4 space-y-3">
      <p className="text-sm font-medium text-gray-900 leading-snug">{question.label}</p>
      <div className="space-y-2">
        <p className="text-sm leading-relaxed text-gray-500">
          We have not explored this yet. Do you want to work through it?
        </p>
        <button
          onClick={(e) => {
            e.stopPropagation();
            // Placeholder — production would call API for focused investigation
          }}
          style={{ cursor: "pointer" }}
          className="rounded-lg border border-blue-600 bg-white px-4 py-2 text-sm font-medium text-blue-700 hover:bg-blue-50 transition"
        >
          Work through this
        </button>
      </div>
      <button
        onClick={() => setIsFocused(false)}
        style={{ cursor: "pointer" }}
        className="text-xs text-gray-400 underline hover:text-gray-600 transition"
      >
        Back to open questions
      </button>
    </div>
  );
}

// ── Current understanding card ────────────────────────────────
function CurrentUnderstandingCard({ currentSummary, plainLanguage }) {
  if (plainLanguage) return <PlainLanguageCard summary={plainLanguage} />;

  const summary = resolveCurrentSummary(currentSummary);

  if (!summary) return null;

  return (
    <div className="rounded-lg border border-gray-100/80 bg-transparent px-6 pt-5 pb-6">
      <h2 className="mb-3 text-[11px] font-semibold tracking-widest uppercase text-gray-500">
        Understanding
      </h2>
      <p className="text-sm leading-relaxed text-gray-600">{summary}</p>
    </div>
  );
}

// ── Plain-language understanding card (from pipeline summary) ──
function PlainLanguageCard({ summary }) {
  if (!summary) return null;

  return (
    <div className="rounded-lg border border-gray-100/80 bg-transparent px-6 pt-5 pb-6">
      <h2 className="mb-3 text-[11px] font-semibold tracking-widest uppercase text-gray-500">
        Understanding
      </h2>
      <p className="text-sm leading-relaxed text-gray-600">{summary}</p>
    </div>
  );
}

// ── Investigation history card (readable notebook style) ──────
function InvestigationHistoryCard({ turn }) {
  const isCollapsed = turn._collapsed;
  const isAnswered = Boolean(turn.answer?.trim());

  const displayedQuestion = turn.question;

  return (
    <details
      className="rounded-lg border border-gray-200/60 bg-gray-50/30"
      key={turn.id}
      open={!isCollapsed}
      data-testid="investigation-turn"
    >
      <summary className="cursor-pointer px-4 py-2 text-sm font-medium text-gray-700 hover:text-gray-900">
        {isAnswered && <span aria-hidden="true">✓ </span>}
        {displayedQuestion}
      </summary>

      <div className="space-y-2 px-4 pb-4 pt-2">
        <p className="text-gray-700">{turn.answer}</p>

        {turn.acknowledgement && (
          <p className="italic text-gray-500">
            {turn.acknowledgement}
          </p>
        )}
      </div>
    </details>
  );
}

// ── Investigation history section ─────────────────────────────
function InvestigationHistory({ turns }) {
  if (!turns || turns.length === 0) return null;

  const latestId = turns[turns.length - 1].id;

  return (
    <div className="space-y-3" data-testid="investigation-history">
      <h2 className="text-[11px] font-semibold tracking-widest uppercase text-gray-500">
        History
      </h2>
      <div className="space-y-2">
        {turns.map((turn) => (
          <InvestigationHistoryCard key={turn.id} data-testid="investigation-turn" turn={{ ...turn, _collapsed: turn.id !== latestId }} />
        ))}
      </div>
    </div>
  );
}

// ── Original situation (always-visible reference card) ────────
function OriginalSituation({ scenario, centralStatement }) {
  const text = scenario || centralStatement;

  if (!text) return null;

  return (
    <div className="rounded-lg border border-gray-200/60 bg-gray-50/40 px-5 py-4">
      <h2 className="mb-2 text-[11px] font-semibold tracking-widest uppercase text-gray-500">
        Situation
      </h2>

      <p className="whitespace-pre-wrap text-sm leading-relaxed text-gray-600">
        {text}
      </p>
    </div>
  );
}

// ── Transient acknowledgement (auto-dismisses after 3s) ─────────

function useAutoDismiss(duration = 3000) {
  const [visible, setVisible] = useState(true);

  useEffect(() => {
    if (!visible) return;
    const timer = setTimeout(() => setVisible(false), duration);
    return () => clearTimeout(timer);
  }, [visible, duration]);

  return visible;
}

function UpdateAcknowledgement({ updateResult }) {
  const visible = useAutoDismiss(3000);

  if (!updateResult || !visible) return null;

  const summary = updateResult.summary;

  return (
    <div
      className="transition-all duration-1500 ease-in"
      style={{ opacity: visible ? 0.7 : 0, maxHeight: visible ? "4rem" : "0", marginBottom: visible ? "1rem" : "0" }}
    >
      <div className="rounded-md border border-blue-200/60 bg-blue-50/30 px-4 py-2 text-xs text-blue-700/60">
        {summary}
      </div>
    </div>
  );
}

// ── Developer details disclosure ──────────────────────────────
function DeveloperDetails({ graph, selectedQuestion, diagnostics, newlySurfacedNodeIds, updateResult }) {
  return (
    <details className="rounded-lg border border-gray-200/60 bg-gray-50/30">
      <summary className="cursor-pointer px-5 py-3 text-sm font-medium text-gray-400 hover:text-gray-600">
        Developer details
      </summary>
      <div className="border-t border-gray-200/60 px-5 pb-4 pt-3 space-y-4">
        {graph && (
          <SituationGraphView
            situationGraph={graph}
            selectedQuestion={selectedQuestion}
            newlySurfacedNodeIds={newlySurfacedNodeIds}
          />
        )}
        {updateResult && (
          <GraphUpdateView updateResult={{ ...updateResult, previousSituationGraph: graph }} />
        )}
        {diagnostics && <DiagnosticsView result={{ diagnostics }} />}
      </div>
    </details>
  );
}

// ── Loading overlay (for both start and update) ───────────────
function LoadingOverlay({ isLoading, elapsed, currentMessage, variant }) {
  if (!isLoading) return null;

  const messages = variant === "update" ? UPDATE_MESSAGES : INITIAL_MESSAGES;
  let statusText = messages[0].text;
  for (const m of messages) {
    if (elapsed >= m.min) statusText = m.text;
  }

  return (
    <div className="rounded-lg border border-blue-200/60 bg-blue-50/40 px-6 py-7" role="status" aria-busy="true" data-testid="loading-overlay">
      <div className="flex items-center gap-3">
        <ActivitySpinner />
        <span className="text-base font-medium text-blue-800/70">Working through your situation</span>
      </div>
      <p className="mt-3 text-sm text-blue-600/60">{statusText}</p>
      <p className="mt-2 text-xs text-blue-400/50" aria-live="polite">
        This has been running for {elapsed}s.
        {variant === "initial" && elapsed >= 45 && (
          <span className="block mt-1">This can take around a minute with the current local model.</span>
        )}
      </p>
    </div>
  );
}

// ── Main workspace component ──────────────────────────────────

function getErrorType(errorStr, stage, hasGraph) {
  if (!errorStr && !stage) return null;
  const lower = (errorStr || "").toLowerCase();
  if (/provider|unavailable|network|timeout/.test(lower)) return "provider-unavailable";
  if (/malformed|invalid.*format|parse|structured/.test(lower)) return "malformed-response";
  if (stage === "provider") return "provider-error";
  if (stage === "unexpected") return "unexpected-state";
  if (/validation/.test(lower) && !hasGraph) return "no-graph";
  return null;
}

// ── Open questions panel (production, non-experiment mode) ────────

function OpenQuestionsPanel({
  graph, selectedPresentationItemId, focusedPresentationItemId, hasFocusedContent,
  focused, formulationStep, formulateMsg, processingStep, deconstructMsg, doneForNowIds,
  startFocused, handleDeconstructSubmit, retryFormulation, setSelectedPresentationItemId,
  setFocusedPresentationItemId, setFocusedAnswer, focusedAnswer, setDoneForNowIds,
}) {
  const openNodes = (graph?.nodes || []).filter(
    (n) => n.kind === "unknown" && n.status !== "resolved" && !doneForNowIds.includes(n.id),
  );
  if (openNodes.length <= 1) return null;

  return (
    <div className="space-y-4">
      <h2 className="text-[11px] font-semibold tracking-widest uppercase text-gray-500">
        Open questions
      </h2>
      <div className="space-y-1">
        {openNodes.map((node) => {
          const isSelected = selectedPresentationItemId === node.id;
          const isFocused = focusedPresentationItemId === node.id;

          return (
            <div key={node.id}>
              <div
                onClick={() => {
                  if (!focused?.question?.trim() || (focused && !hasFocusedContent())) {
                    setSelectedPresentationItemId(
                      selectedPresentationItemId === node.id ? null : node.id,
                    );
                  }
                }}
                style={{ cursor: "pointer" }}
                className="w-full text-left rounded-lg border border-gray-200 px-4 py-3 transition hover:border-gray-300 hover:bg-white"
              >
                <p className={`leading-snug ${isSelected ? "text-sm font-medium text-gray-900" : "text-sm text-gray-600"}`}>
                  {node.label}
                </p>

                {isSelected && !hasFocusedContent() && (
                  <div className="mt-3 space-y-3">
                    <p className="text-sm leading-relaxed text-gray-500">
                      We have not explored this yet. Do you want to work through it?
                    </p>
                    <button
                      onClick={(e) => { e.stopPropagation(); startFocused(node.id); }}
                      style={{ cursor: "pointer" }}
                      className="rounded-lg border border-blue-600 bg-white px-4 py-2 text-sm font-medium text-blue-700 hover:bg-blue-50 transition"
                    >
                      Work through this
                    </button>
                  </div>
                )}

                {isFocused && (() => {
                  const focusedNode = graph?.nodes.find((n) => n.id === node.id);
                  return (
                    <div className="mt-4 space-y-4">
                      {hasFocusedContent() && (
                        <div className="space-y-4 rounded-lg border border-gray-200 bg-white p-5">
                          {focused?.question?.trim() ? (
                            <div>
                              <h3 className="mb-1 text-[11px] font-semibold tracking-widest uppercase text-gray-500">Question</h3>
                              <p className="text-base font-medium leading-relaxed text-gray-900">{focused.question}</p>
                            </div>
                          ) : formulationStep === "active" ? (
                            <p className="text-sm text-blue-600/70">{formulateMsg}</p>
                          ) : null}

                          {focused?.question?.trim() && processingStep !== "active" && focused.status === "formulated" && (
                            <div>
                              <label htmlFor={`rw-answer-${node.id}`} className="mb-2 block text-sm font-medium text-gray-700">Your response</label>
                              <textarea id={`rw-answer-${node.id}`} value={focusedAnswer} onChange={(e) => setFocusedAnswer(e.target.value)} rows={4} data-testid="response-textarea" className="w-full rounded-lg border border-gray-300 px-4 py-3 text-sm focus:border-gray-500 focus:outline-none focus:ring-2 focus:ring-gray-400 disabled:cursor-not-allowed disabled:opacity-60" placeholder="What do you know about this?" />
                              <button onClick={(e) => { e.stopPropagation(); handleDeconstructSubmit(focusedPresentationItemId, focusedAnswer); }} disabled={!focusedAnswer.trim() || processingStep === "active"} style={{ cursor: !focusedAnswer.trim() || processingStep === "active" ? "not-allowed" : "pointer" }} className="mt-3 rounded-lg border border-green-600 bg-white px-4 py-2 text-sm font-medium text-green-700 hover:bg-green-50 transition disabled:opacity-50">Submit response</button>
                            </div>
                          )}

                          {processingStep === "active" && <p className="text-sm text-blue-600/70">{deconstructMsg}</p>}

                          {focused?.result && (
                            <>
                              <div><h3 className="mb-1 text-[11px] font-semibold tracking-widest uppercase text-gray-500">What we learned</h3><ul className="list-disc pl-5 space-y-1">{focused.result.observations.map((o, i) => (<li key={i} className="text-sm leading-relaxed text-gray-700">{o}</li>))}</ul></div>
                              <div><h3 className="mb-1 text-[11px] font-semibold tracking-widest uppercase text-gray-500">Still unclear</h3><ul className="list-disc pl-5 space-y-1">{focused.result.uncertainties.map((u, i) => (<li key={i} className="text-sm leading-relaxed text-gray-700">{u}</li>))}</ul></div>
                              {focused.result.assumptions?.length > 0 && <div><h3 className="mb-1 text-[11px] font-semibold tracking-widest uppercase text-gray-500">Assumptions in this response</h3><ul className="list-disc pl-5 space-y-1">{focused.result.assumptions.map((a, i) => (<li key={i} className="text-sm leading-relaxed text-gray-700">{a}</li>))}</ul></div>}
                              {focused.result.relationships?.length > 0 && <div><h3 className="mb-1 text-[11px] font-semibold tracking-widest uppercase text-gray-500">Connections</h3><ul className="list-disc pl-5 space-y-1">{focused.result.relationships.map((r, i) => (<li key={i} className="text-sm leading-relaxed text-gray-700">{r.from} → {r.to} ({r.type})</li>))}</ul></div>}
                              {focused.result.possibleFollowUpQuestions?.length > 0 && <div><h3 className="mb-1 text-[11px] font-semibold tracking-widest uppercase text-gray-500">Questions this raises</h3><ul className="list-disc pl-5 space-y-1">{focused.result.possibleFollowUpQuestions.map((q, i) => (<li key={i} className="text-sm leading-relaxed text-gray-700">{q}</li>))}</ul></div>}
                            </>
                          )}

                          {focused?.error && processingStep !== "active" && (
                            <div className="rounded-md border border-amber-200 bg-amber-50 px-4 py-3 text-sm text-amber-800">We were unable to process your request right now. Please try again later.<button onClick={(e) => { e.stopPropagation(); retryFormulation(); }} className="ml-2 font-medium underline">Retry</button></div>
                          )}
                        </div>
                      )}

                      <div className="mt-4 mb-3 flex items-center justify-between gap-4">
                        <button onClick={(e) => { e.stopPropagation(); setFocusedPresentationItemId(null); }} style={{ cursor: "pointer" }} className="text-sm text-gray-400 underline hover:text-gray-600 transition whitespace-nowrap">Back to open questions</button>
                        <button onClick={(e) => { e.stopPropagation(); setFocusedPresentationItemId(null); setDoneForNowIds((prev) => [...prev, node.id]); }} style={{ cursor: "pointer" }} className="rounded-lg border border-gray-300 bg-white px-4 py-2 text-sm font-medium text-gray-600 hover:bg-gray-50 transition whitespace-nowrap">Done for now</button>
                      </div>
                    </div>
                  );
                })()}
              </div>
            </div>
          );
        })}
      </div>

      {doneForNowIds.length > 0 && (
        <div className="pt-3 border-t border-gray-200">
          <h3 className="mb-2 text-[11px] font-semibold tracking-widest uppercase text-gray-500">Done for now</h3>
          <div className="space-y-1">
            {graph.nodes.filter((n) => doneForNowIds.includes(n.id)).map((node) => (
              <div key={node.id} className="rounded-lg border border-gray-200/60 bg-gray-50/40 px-4 py-3">
                <p className="text-sm text-gray-500 leading-snug">{node.label}</p>
                <button onClick={() => setDoneForNowIds(doneForNowIds.filter(id => id !== node.id))} style={{ cursor: "pointer" }} className="mt-2 rounded border border-gray-300 px-3 py-1 text-xs font-medium text-gray-500 hover:bg-white transition">Reopen</button>
              </div>
            ))}
          </div>
        </div>
      )}
    </div>
  );
}

export default function ReasoningWorkspace({
  scenario,
  status,
  updateStatus,
  currentUnderstanding: propUnderstanding,
  result,
  answer,
  setAnswer,
  onAnswerSubmit,
  lastSubmittedAnswer,
  onRestart,
}) {
  const [investigationHistory, setInvestigationHistory] = useState([]);
  const turnCounter = useRef(0);
  const pendingTurnRef = useRef(null);
  // ── Experiment 12: toggle between progress panel versions (temporary experimental UI) ──
  const [panelVariant, setPanelVariant] = useState("c");

  // ── RTO.01 — presentation-only selection for open investigation items ──
  const [selectedPresentationItemId, setSelectedPresentationItemId] = useState(null);

  // ── RTO.02 — case / question workspace lifecycle (presentation only) ──
  const [focusedPresentationItemId, setFocusedPresentationItemId] = useState(null);
  const [doneForNowIds, setDoneForNowIds] = useState([]);

  // ── RTO.29D — post-Analyse initial reflection surface ─────────
  const [initialReflectionActive, setInitialReflectionActive] = useState(false);
  const [postAnalyseStatus, setPostAnalyseStatus] = useState(null);

  const { saveSession, loadSession } = useSessionPersistence();

  // Persist workspace state on every successful update (Phase 3)
  useEffect(() => {
    if (updateStatus === "success" && result?.situationGraph) {
      saveSession({
        scenario,
        situationGraph: result.situationGraph,
        selectedQuestion: result.selectedQuestion,
        summary: result.summary || propUnderstanding,
        updatedAt: new Date().toISOString(),
      });
    }
  }, [updateStatus, result]);

  // Capture the current selected question at submit time (not from a stale ref)
  const capturePendingTurn = (selectedQuestion, answerText) => {
    if (!selectedQuestion || !answerText?.trim()) return null;
    const q = typeof selectedQuestion === "string" ? selectedQuestion : selectedQuestion.question;
    if (!q) return null;
    turnCounter.current += 1;
    return {
      id: `turn-${turnCounter.current}`,
      question: q,
      answer: answerText.trim(),
      acknowledgement: null,
    };
  };

  // Append the captured pending turn to history after a successful update only
  useEffect(() => {
    const pending = pendingTurnRef.current;
    if (!pending || updateStatus !== "success") return;

    setInvestigationHistory((prev) => [
      ...prev,
      { ...pending, acknowledgement: result?.summary || null },
    ]);
    pendingTurnRef.current = null;
  }, [updateStatus, result]);

  const handleUpdateCaptureAndSubmit = async (e) => {
    e.preventDefault();
    if (!answer?.trim() || !result?.selectedQuestion) return;
    pendingTurnRef.current = capturePendingTurn(result.selectedQuestion, answer);
    await onAnswerSubmit(e);
  };

  const graph = result?.situationGraph ?? null;
  const hasGraph = Boolean(graph);
  const diagnostics = result?.diagnostics ?? null;
  const newlySurfacedNodeIds = result?.newlySurfacedNodeIds || [];
  const genuineCompletion = hasGenuineCompletion(graph);

  const errorType = getErrorType(
    result?.error || (result?.updateError ? result.updateError.error : null),
    result?.stage,
    Boolean(graph)
  );

  const isProviderUnavailable =
    errorType === "provider-unavailable" || errorType === "provider-error";
  const isMalformedResponse = errorType === "malformed-response";

  // ── RTO.13B — focused investigation localized state ───────────

  const [formulationStep, setFormulationStep] = useState("idle");
  const [processingStep, setProcessingStep] = useState("idle");

  const { elapsed: startElapsed, currentMessage: startMsg } = useLoadingStatus(
    INITIAL_MESSAGES,
    status === "loading"
  );

  const { elapsed: updateElapsed, currentMessage: updateMsg } = useLoadingStatus(
    UPDATE_MESSAGES,
    updateStatus === "loading"
  );

  // ── RTO.13B — focused investigation loading hooks ─────────────

  const FORMULATING_MESSAGES = [
    { min: 0, text: "Working out a question…" },
    { min: 15, text: "Still working on that question" },
    { min: 30, text: "Formulating the right question for this" },
    { min: 45, text: "A moment longer — this can take around a minute" },
  ];

  const DECONSTRUCT_MESSAGES = [
    { min: 0, text: "Working through your response…" },
    { min: 15, text: "Still working on that response" },
    { min: 30, text: "A moment longer — this can take around a minute" },
  ];

  const { elapsed: formulateElapsed, currentMessage: formulateMsg } = useLoadingStatus(
    FORMULATING_MESSAGES,
    formulationStep === "active",
  );

  const { elapsed: deconstructElapsed, currentMessage: deconstructMsg } = useLoadingStatus(
    DECONSTRUCT_MESSAGES,
    processingStep === "active",
  );

  const isUpdating = updateStatus === "loading";
  const hasSelectedQuestion = Boolean(result?.selectedQuestion);

  // ── RTO.13B — focused investigation localized state (keyed by node ID) ──
  const [focusedInvestigations, setFocusedInvestigations] = useState({});
  const [focusedAnswer, setFocusedAnswer] = useState("");

  function getFocusedInvestigation() {
    if (!focusedPresentationItemId) return null;
    return focusedInvestigations[focusedPresentationItemId] || null;
  }

  function focusItem(nodeId) {
    setSelectedPresentationItemId(nodeId);
    setFocusedPresentationItemId(nodeId);
  }

  const focused = getFocusedInvestigation();

  // ── RTO.13B — workflow handlers ──────────────────────────────

  function startFocused(nodeId) {
    const target = nodeId || focusedPresentationItemId;
    if (!target) return;
    setFocusedPresentationItemId(target);
    setFocusedAnswer("");
    setFormulationStep("active");
    setFocusedInvestigations((prev) => ({
      ...prev,
      [target]: { status: "formulating", question: "", answer: null, result: null, error: null },
    }));
    doFormulate(target);
  }

  async function doFormulate(targetNodeId) {
    const nodeId = targetNodeId || focusedPresentationItemId;
    if (!nodeId || !hasGraph) return;
    try {
      const url = "/api/focused-investigation/formulate";
      const res = await fetch(url, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ situationGraph: graph, targetNodeId: nodeId }),
      });
      const data = await res.json();
      if (!data.success) throw new Error(data.error || "Formulation failed");
      setFocusedInvestigations((prev) => ({
        ...prev,
        [nodeId]: { ...prev[nodeId], question: data.question, status: "formulated", error: null },
      }));
      setFormulationStep("idle");
    } catch (err) {
      setFocusedInvestigations((prev) => ({
        ...prev,
        [focusedPresentationItemId]: { ...prev[focusedPresentationItemId], question: "", error: err.message || "Formulation failed" },
      }));
    }
  }

  async function handleDeconstructSubmit(targetNodeId, answerText) {
    if (!hasGraph) return;

    const targetNode = graph?.nodes?.find((n) => n.id === targetNodeId);
    const centralStmt = graph?.centralStatement || scenario || "";

    setProcessingStep("active");

    try {
      const url = "/api/focused-investigation/deconstruct";

      const res = await fetch(url, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          targetNodeId: targetNodeId,
          targetLabel: targetNode?.label || "",
          targetDescription: targetNode?.description || "",
          centralStatement: centralStmt,
          question: focused.question,
          answer: answerText,
        }),
      });

      const data = await res.json();

      if (!data.success) throw new Error(data.error || "Deconstruction failed");

      setProcessingStep("idle");
      setFocusedInvestigations((prev) => ({
        ...prev,
        [targetNodeId]: { ...prev[targetNodeId], result: data, answer: answerText, error: null },
      }));
    } catch (err) {
      setProcessingStep("idle");
      setFocusedInvestigations((prev) => ({
        ...prev,
        [targetNodeId]: { ...prev[targetNodeId], result: null, error: err.message || "Deconstruction failed" },
      }));
    }
  }

  async function submitFocusedAnswer() {
    if (!focused?.question?.trim() || !hasGraph) return;
    const targetNodeId = focusedPresentationItemId;
    await handleDeconstructSubmit(targetNodeId, focusedAnswer);
  }

  function retryFormulation() {
    const target = focusedPresentationItemId;
    if (!target) return;
    setFocusedInvestigations((prev) => ({
      ...prev,
      [target]: { ...prev[target], question: "", error: null },
    }));
    doFormulate(target);
  }

  function hasFocusedContent() {
    if (!focused) return false;
    const q = focused.question;
    return Boolean(q?.trim()) || formulationStep === "active" || processingStep === "active" || focused.error;
  }

  // ── End RTO.13B ──────────────────────────────────────────────

  const canAnswer =
    status === "success" &&
    !isUpdating &&
    Boolean(result?.situationGraph) &&
    hasSelectedQuestion;

  const selectedQ = result?.selectedQuestion ?? null;

  // Determine whether the Current Understanding card should render:
  // — when there is a durable plain-language understanding, or
  // — when there is an actual summary from any graph snapshot, or
  // — when the investigation has reached a terminal state with no active question.
  const hasCurrentSummaryCondition =
    Boolean(propUnderstanding || graph?.currentSummary || result?.updatedSituationGraph?.currentSummary) || !hasSelectedQuestion;

  // ── RTO.29D — manage initial reflection lifecycle ────────────
  useEffect(() => {
    const entering = status === "success" && hasGraph && propUnderstanding && !hasSelectedQuestion;
    if (entering) {
      setPostAnalyseStatus("success");
      setInitialReflectionActive(true);
    } else if (!entering && initialReflectionActive) {
      // Leave initial reflection when something changes (user interacts, status shifts)
      setInitialReflectionActive(false);
      setPostAnalyseStatus(null);
    }
  }, [status, result, hasGraph]);

  // Deactivate initial reflection when user does anything meaningful
  useEffect(() => {
    if (!initialReflectionActive) return;
    if (selectedPresentationItemId || focusedPresentationItemId || investigationHistory.length > 0 || formulationStep !== "idle" || processingStep !== "idle") {
      setInitialReflectionActive(false);
      setPostAnalyseStatus(null);
    }
  }, [selectedPresentationItemId, focusedPresentationItemId, investigationHistory, formulationStep, processingStep]);

  return (
    <div className="space-y-6" data-testid="reasoning-workspace">
      {/* ── Loading overlays ─────────────────────────────── */}
      {status === "loading" && (
        <LoadingOverlay
          isLoading={true}
          elapsed={startElapsed}
          currentMessage={startMsg}
          variant="initial"
        />
      )}

      {/* ── Provider unavailable recovery (always visible) ───────────── */}
      {isProviderUnavailable && (
        <ProviderUnavailableCard onRestart={onRestart} />
      )}

      {/* ── Malformed response recovery (always visible) ──────────────── */}
      {isMalformedResponse && (
        <MalformedResponseCard onRestart={onRestart} />
      )}

      {/* ── Unexpected state recovery ──────────────────── */}
      {(errorType === "unexpected-state") && result && (
        <UnexpectedStateCard
          stateName={result.stage || null}
          onRetry={updateStatus === "error" ? onRestart : null}
          onRestart={onRestart}
        />
      )}

      {/* ── No graph produced after initial analysis ───────── */}
      {(status === "success" || status === "error") && !graph ? (
        <div className="rounded-lg border border-yellow-300 bg-yellow-50 px-4 py-3 text-sm text-yellow-800">
          {diagnostics?.noQuestionReason
            ? "Validation failed — no structured graph output was produced."
            : "The analysis completed but did not produce a structured result."}
        </div>
      ) : (
        <>
          {/* ── RTO.29D — initial post-Analyse reflection ──────── */}
          {postAnalyseStatus === "success" && (
            <div className="space-y-6" data-testid="initial-reflection-surface">
              {/* What I understood */}
              <div className="rounded-lg border border-blue-200/60 bg-blue-50/40 px-6 pt-5 pb-6">
                <h2 className="mb-3 text-[11px] font-semibold tracking-widest uppercase text-gray-500">
                  What I understood
                </h2>
                <p className="text-sm leading-relaxed text-gray-700">{propUnderstanding}</p>
              </div>

              {/* Initial proposed findings */}
              <div className="space-y-3" data-testid="initial-proposed-findings">
                <h2 className="text-[11px] font-semibold tracking-widest uppercase text-gray-500">
                  Initial proposed findings
                </h2>
                {(() => {
                  const resolvedIds = new Set(graph?.resolvedNodeIds || []);
                  return (
                    graph?.nodes?.map((node) =>
                      node.kind === "unknown" && node.status !== "resolved" && !resolvedIds.has(node.id) ? (
                        <button
                          key={node.id}
                          onClick={() => startFocused(node.id)}
                          style={{ cursor: "pointer" }}
                          className="w-full text-left rounded-lg border border-gray-200 bg-white px-5 py-4 transition hover:border-gray-300 hover:bg-gray-50"
                        >
                          <span className="block text-sm leading-relaxed text-gray-900">{node.label}</span>
                          {node.description && node.description !== node.label && (
                            <p className="mt-1.5 text-xs leading-snug text-gray-500">{node.description}</p>
                          )}
                        </button>
                      ) : null,
                    ) || []
                  );
                })()}
              </div>
            </div>
          )}

          {/* ── Workspace grid: persistent whenever a graph exists ─── */}
          {hasGraph && (
            <div className="grid grid-cols-1 gap-6 lg:grid-cols-3">
              {/* ── Left lane: active conversation & notebook ───────── */}
              <div className={`space-y-6 ${hasGraph ? 'lg:col-span-2' : 'lg:col-span-full'}`}>
                {/* Current investigation (prominent hero section) */}
                {postAnalyseStatus !== "success" && (
                  <CurrentInvestigationCard selectedQuestion={result?.selectedQuestion} graph={graph} />
                )}

                {/* ── Open questions (case workspace) — no ranking bias ── */}
                {postAnalyseStatus !== "success" && (
                  <OpenQuestionsPanel
                    graph={graph}
                    selectedPresentationItemId={selectedPresentationItemId}
                    focusedPresentationItemId={focusedPresentationItemId}
                    hasFocusedContent={hasFocusedContent}
                    focused={getFocusedInvestigation()}
                    formulationStep={formulationStep}
                    formulateMsg={formulateMsg}
                    processingStep={processingStep}
                    deconstructMsg={deconstructMsg}
                    doneForNowIds={doneForNowIds}
                    startFocused={startFocused}
                    handleDeconstructSubmit={handleDeconstructSubmit}
                    retryFormulation={retryFormulation}
                    setSelectedPresentationItemId={setSelectedPresentationItemId}
                    setFocusedPresentationItemId={setFocusedPresentationItemId}
                    setFocusedAnswer={setFocusedAnswer}
                    focusedAnswer={focusedAnswer}
                    setDoneForNowIds={setDoneForNowIds}
                  />
                )}

                {/* Terminal state — suppressed during initial reflection */}
                {postAnalyseStatus !== "success" && status === "success" && !hasSelectedQuestion && (
                  <>
                    {genuineCompletion && (
                      <CompletionCard summary={resolveCurrentSummary(propUnderstanding || graph?.currentSummary || result?.updatedSituationGraph?.currentSummary)} />
                    )}
                    {!genuineCompletion ? (
                      <EvidenceLimitCard summary={resolveCurrentSummary(propUnderstanding || graph?.currentSummary || result?.updatedSituationGraph?.currentSummary)} />
                    ) : null}
                  </>
                )}

                {investigationHistory.length > 0 && (
                  <InvestigationHistory turns={investigationHistory} />
                )}

                {/* Supporting context within conversation lane */}
                {hasCurrentSummaryCondition && (
                  <>
                    {postAnalyseStatus !== "success" && (
                      <CurrentUnderstandingCard currentSummary={graph?.currentSummary || result?.updatedSituationGraph?.currentSummary} plainLanguage={propUnderstanding || null} />
                    )}
                    {/* ── Experiment 12: progress panel A / B / C toggle (temporary experimental UI) — de-emphasised by branch-as-context experiment RTO.25D */}
                    {hasGraph && (
                      <div className="hidden space-y-2">
                        <div className="flex items-center gap-2" role="radiogroup" aria-label="Progress panel variant">
                          <button
                            role="radio"
                            aria-checked={panelVariant === "a"}
                            onClick={() => setPanelVariant("a")}
                            onKeyDown={(e) => {
                              if (e.key === "ArrowRight") setPanelVariant("b");
                              if (e.key === "ArrowLeft") setPanelVariant("c");
                            }}
                            className={`text-xs transition ${panelVariant === "a" ? "font-medium text-gray-700 underline" : "text-gray-400 hover:text-gray-500"}`}
                          >
                            A
                          </button>
                          <span className="text-gray-300">/</span>
                          <button
                            role="radio"
                            aria-checked={panelVariant === "b"}
                            onClick={() => setPanelVariant("b")}
                            onKeyDown={(e) => {
                              if (e.key === "ArrowRight") setPanelVariant("c");
                              if (e.key === "ArrowLeft") setPanelVariant("a");
                            }}
                            className={`text-xs transition ${panelVariant === "b" ? "font-medium text-gray-700 underline" : "text-gray-400 hover:text-gray-500"}`}
                          >
                            B
                          </button>
                          <span className="text-gray-300">/</span>
                          <button
                            role="radio"
                            aria-checked={panelVariant === "c"}
                            onClick={() => setPanelVariant("c")}
                            onKeyDown={(e) => {
                              if (e.key === "ArrowRight") setPanelVariant("a");
                              if (e.key === "ArrowLeft") setPanelVariant("b");
                            }}
                            className={`text-xs transition ${panelVariant === "c" ? "font-medium text-gray-700 underline" : "text-gray-400 hover:text-gray-500"}`}
                          >
                            C (exp)
                          </button>
                        </div>
                        <div className="opacity-75">
                          {panelVariant === "a"
                            ? <InvestigationSummaryPanel graph={graph} selectedQuestion={selectedQ} result={result} updateStatus={updateStatus} />
                            : panelVariant === "b"
                              ? <InvestigationSummaryPanelV2 graph={graph} selectedQuestion={selectedQ} result={result} updateStatus={updateStatus} />
                              : <InvestigationSummaryPanelV3 graph={graph} selectedQuestion={selectedQ} result={result} />
                          }
                        </div>
                      </div>
                    )}
                  </>
                )}
              </div>

              {/* ── Right lane: stable supporting reference ───────── */}
              {hasCurrentSummaryCondition && (
                <div className="space-y-6 lg:col-span-1">
                  {/* RTO.26B — situation card from scenario text when no graph */}
                  {!graph && scenario && (
                    <div className="rounded-lg border border-gray-200/60 bg-gray-50/40 px-5 py-4">
                      <h2 className="mb-2 text-[11px] font-semibold tracking-widest uppercase text-gray-500">
                        Situation
                      </h2>
                      <p className="whitespace-pre-wrap text-sm leading-relaxed text-gray-600">
                        {scenario}
                      </p>
                    </div>
                  )}
                  {graph && postAnalyseStatus !== "success" && <OriginalSituation scenario={scenario} centralStatement={graph?.centralStatement} />}
                  {/* RTO.25B — temporarily hidden to reduce competing navigation while branch-experiment is active */}
                  <div className="hidden">
                    <InvestigationMap turnCount={investigationHistory.length} />
                  </div>
                </div>
              )}
            </div>
          )}

          {/* Developer details — full-width beneath workspace */}
          {(status === "success" || status === "error") && graph && (
            <DeveloperDetails
              graph={graph}
              selectedQuestion={selectedQ}
              diagnostics={diagnostics}
              newlySurfacedNodeIds={newlySurfacedNodeIds}
              updateResult={updateStatus === "success" ? result : null}
            />
          )}
        </>
      )}

      {/* ── Errors (always visible above debug) ─────────── */}
      {(status === "error" || updateStatus === "error") && (
        <div className="space-y-3">
          {status === "error" && result?.error && (
            <div className="rounded-lg border border-red-300 bg-red-50 px-4 py-3 text-sm text-red-700 whitespace-pre-wrap">
              Error: {result.error}
            </div>
          )}
          {updateStatus === "error" && !isProviderUnavailable && !isMalformedResponse && result?.updateError && (
            <div className="rounded-lg border border-red-300 bg-red-50 px-4 py-3 text-sm text-red-700">
              Update error: {result.updateError.error || JSON.stringify(result.updateError)}
            </div>
          )}
        </div>
      )}
    </div>
  );
}

export { useLoadingStatus, INITIAL_MESSAGES, UPDATE_MESSAGES, LoadingOverlay, resolveCurrentSummary, isTechnicalSummary, ContinueLaterBanner };