// SPEC: PJ2026-01040111 long-running Workbench observation.
// Responsibility: Analyzer browser process, memory, responsiveness, and root-cause signal source fragment.

export function nodeWebObserveAnalyzerBrowserProcessSource(): string {
  return String.raw`function buildBrowserProcessReport(rows) {
  const blockerEvents = (Array.isArray(rows) ? rows : [])
    .filter((item) => item && item.type === "browser-freeze-blocker")
    .map(compactBrowserFreezeBlockerEvent)
    .filter(Boolean);
  const samples = (Array.isArray(rows) ? rows : [])
    .filter((item) => item && (item.type === "browser-process-sample" || item.process || item.pages))
    .map((item) => ({ ...item, tsMs: Date.parse(String(item.ts || "")) }))
    .filter((item) => Number.isFinite(item.tsMs))
    .sort((a, b) => a.tsMs - b.tsMs);
  const memorySamples = samples.map((item) => {
    const process = item.process && typeof item.process === "object" ? item.process : {};
    const growth = item.growth && typeof item.growth === "object" ? item.growth : {};
    const totalRssBytes = browserMetricNumber(process.totalRssBytes);
    const maxProcessRssBytes = browserMetricNumber(process.maxProcessRssBytes);
    return {
      ts: item.ts,
      tsMs: item.tsMs,
      seq: item.seq ?? null,
      sampleSeq: item.sampleSeq ?? null,
      commandId: item.commandId ?? null,
      processCount: browserMetricNumber(process.chromiumProcessCount),
      totalRssBytes,
      totalRssMb: bytesToMb(totalRssBytes),
      maxProcessRssBytes,
      maxProcessRssMb: bytesToMb(maxProcessRssBytes),
      maxProcess: compactBrowserProcessRow(process.maxProcess),
      totalRssGrowthBytes: browserMetricNumber(growth.totalRssGrowthBytes),
      totalRssGrowthMb: bytesToMb(growth.totalRssGrowthBytes),
      maxProcessRssGrowthBytes: browserMetricNumber(growth.maxProcessRssGrowthBytes),
      maxProcessRssGrowthMb: bytesToMb(growth.maxProcessRssGrowthBytes),
      roles: process.roles && typeof process.roles === "object" ? process.roles : {},
      valuesRedacted: true,
    };
  });
  const computedGrowth = computeBrowserProcessGrowth(memorySamples, alertThresholds.browserRssGrowthWindowMs);
  const pageEvents = [];
  const cdpTimeoutEvents = [];
  for (const sample of samples) {
    for (const page of Array.isArray(sample.pages) ? sample.pages : []) {
      const responsiveness = page?.responsiveness && typeof page.responsiveness === "object" ? page.responsiveness : {};
      const cdp = page?.cdp && typeof page.cdp === "object" ? page.cdp : {};
      const calls = Array.isArray(cdp.calls) ? cdp.calls : [];
      const event = {
        ts: sample.ts,
        tsMs: sample.tsMs,
        seq: sample.seq ?? null,
        sampleSeq: sample.sampleSeq ?? null,
        commandId: sample.commandId ?? null,
        pageRole: page?.pageRole ?? null,
        pageId: page?.pageId ?? null,
        pageEpoch: page?.pageEpoch ?? null,
        url: safeReportUrl(page?.url),
        timeoutMs: browserMetricNumber(page?.timeoutMs),
        responsivenessOk: responsiveness.ok === true,
        responsivenessTimeout: responsiveness.timeout === true,
        responsivenessLatencyMs: browserMetricNumber(responsiveness.latencyMs),
        cdpTimeoutCount: browserMetricNumber(cdp.timeoutCount),
        cdpErrorCount: browserMetricNumber(cdp.errorCount),
        heapUsedMb: page?.heapUsage ? bytesToMb(page.heapUsage.usedSize) : null,
        heapTotalMb: page?.heapUsage ? bytesToMb(page.heapUsage.totalSize) : null,
        effectiveHeapUsedMb: page?.effectiveMemory ? browserMetricNumber(page.effectiveMemory.effectiveHeapUsedMb) : null,
        effectiveJsHeapUsedMb: page?.effectiveMemory ? browserMetricNumber(page.effectiveMemory.effectiveJsHeapUsedMb) : null,
        heapUsedGrowthMb: page?.effectiveMemory ? browserMetricNumber(page.effectiveMemory.heapUsedGrowthMb) : null,
        jsHeapUsedGrowthMb: page?.effectiveMemory ? browserMetricNumber(page.effectiveMemory.jsHeapUsedGrowthMb) : null,
        baselineCapturedAt: page?.baseline?.capturedAt ?? null,
        domNodes: page?.domCounters ? browserMetricNumber(page.domCounters.nodes) : null,
        valuesRedacted: true,
      };
      pageEvents.push(event);
      for (const call of calls) {
        if (call?.timeout !== true || call?.method === "Runtime.evaluate") continue;
        cdpTimeoutEvents.push({
          ...event,
          method: call.method ?? null,
          latencyMs: browserMetricNumber(call.latencyMs),
          errorMessage: limitText(call.error?.message ?? "", 180),
          valuesRedacted: true,
        });
      }
      const callTimeoutCount = calls.filter((call) => call?.timeout === true && call?.method !== "Runtime.evaluate").length;
      if (Number(event.cdpTimeoutCount || 0) > callTimeoutCount && calls.length === 0) {
        cdpTimeoutEvents.push({ ...event, method: "cdp-session", latencyMs: event.responsivenessLatencyMs, errorMessage: "CDP session or metric collection timed out", valuesRedacted: true });
      }
    }
  }
  const responsivenessEvents = pageEvents.filter((item) => item.responsivenessTimeout === true || Number(item.responsivenessLatencyMs ?? 0) >= alertThresholds.playwrightResponsivenessRedMs);
  const maxTotal = maxByNumber(memorySamples, (item) => item.totalRssBytes);
  const maxProcess = maxByNumber(memorySamples, (item) => item.maxProcessRssBytes);
  const maxGrowth = maxByNumber(computedGrowth, (item) => item.totalRssGrowthBytes);
  const maxProcessGrowth = maxByNumber(computedGrowth, (item) => item.maxProcessRssGrowthBytes);
  return {
    summary: {
      sampleCount: samples.length,
      memorySampleCount: memorySamples.length,
      pageMetricCount: pageEvents.length,
      cdpMetricsTimeoutCount: cdpTimeoutEvents.length,
      responsivenessSlowCount: responsivenessEvents.length,
      responsivenessTimeoutCount: responsivenessEvents.filter((item) => item.responsivenessTimeout === true).length,
      maxTotalRssMb: maxTotal ? bytesToMb(maxTotal.totalRssBytes) : null,
      maxProcessRssMb: maxProcess ? bytesToMb(maxProcess.maxProcessRssBytes) : null,
      maxTotalRssGrowthMb: maxGrowth ? bytesToMb(maxGrowth.totalRssGrowthBytes) : null,
      maxProcessRssGrowthMb: maxProcessGrowth ? bytesToMb(maxProcessGrowth.maxProcessRssGrowthBytes) : null,
      totalRssRedMb: alertThresholds.browserTotalRssRedMb,
      processRssRedMb: alertThresholds.browserProcessRssRedMb,
      growthRedMb: alertThresholds.browserRssGrowthRedMb,
      growthWindowMs: alertThresholds.browserRssGrowthWindowMs,
      responsivenessRedMs: alertThresholds.playwrightResponsivenessRedMs,
      memoryRedPolicyScope: "per-page-effective-memory",
      freezeBlockerCount: blockerEvents.length,
      browserFreezePolicy,
      valuesRedacted: true,
    },
    blockerEvents: blockerEvents.slice(-20),
    memorySamples: memorySamples.slice(-60),
    growthSamples: computedGrowth.slice(-60),
    maxTotalRssSample: maxTotal,
    maxProcessRssSample: maxProcess,
    maxGrowthSample: maxGrowth,
    maxProcessGrowthSample: maxProcessGrowth,
    responsivenessEvents: responsivenessEvents.slice(-80),
    cdpTimeoutEvents: cdpTimeoutEvents.slice(-80),
    latestPageEvents: pageEvents.slice(-20),
    valuesRedacted: true,
  };
}

function compactBrowserFreezeBlockerEvent(item) {
  if (!item || typeof item !== "object") return null;
  const observed = objectValue(item.observed);
  const threshold = objectValue(item.threshold);
  const sample = objectValue(item.sample);
  const page = objectValue(item.page);
  const browserKill = objectValue(item.browserKill);
  return {
    ts: item.ts ?? null,
    seq: item.seq ?? null,
    sampleSeq: item.sampleSeq ?? sample.sampleSeq ?? null,
    kind: item.kind ?? null,
    severity: item.severity ?? "red",
    blocking: item.blocking === true,
    summary: item.summary ? String(item.summary).slice(0, 240) : null,
    rootCause: item.rootCause ?? null,
    rootCauseStatus: item.rootCauseStatus ?? null,
    rootCauseConfidence: item.rootCauseConfidence ?? null,
    policySource: item.policySource ?? null,
    fallbackAllowed: item.fallbackAllowed === true,
    observerRefreshAllowed: item.observerRefreshAllowed === true,
    observed: {
      totalRssMb: numberOrNull(observed.totalRssMb),
      processRssMb: numberOrNull(observed.processRssMb),
      totalGrowthMb: numberOrNull(observed.totalGrowthMb),
      processGrowthMb: numberOrNull(observed.processGrowthMb),
      effectiveHeapUsedMb: numberOrNull(observed.effectiveHeapUsedMb),
      effectiveJsHeapUsedMb: numberOrNull(observed.effectiveJsHeapUsedMb),
      heapGrowthMb: numberOrNull(observed.heapGrowthMb),
      jsHeapGrowthMb: numberOrNull(observed.jsHeapGrowthMb),
      responsivenessLatencyMs: numberOrNull(observed.responsivenessLatencyMs),
      responsivenessTimeout: observed.responsivenessTimeout === true,
      cdpMetricsTimeoutCount: numberOrNull(observed.cdpMetricsTimeoutCount),
      methods: arrayStrings(observed.methods).slice(0, 8),
      valuesRedacted: true,
    },
    threshold: {
      totalRssBlockerMb: numberOrNull(threshold.totalRssBlockerMb),
      processRssBlockerMb: numberOrNull(threshold.processRssBlockerMb),
      growthBlockerMb: numberOrNull(threshold.growthBlockerMb),
      latencyBlockerMs: numberOrNull(threshold.latencyBlockerMs),
      eventBlockerCount: numberOrNull(threshold.eventBlockerCount),
      metricsTimeoutBlockerCount: numberOrNull(threshold.metricsTimeoutBlockerCount),
      windowMs: numberOrNull(threshold.windowMs),
      valuesRedacted: true,
    },
    sample: {
      ts: sample.ts ?? null,
      seq: sample.seq ?? null,
      sampleSeq: sample.sampleSeq ?? null,
      browserPid: numberOrNull(sample.browserPid),
      totalRssMb: numberOrNull(sample.totalRssMb),
      maxProcessRssMb: numberOrNull(sample.maxProcessRssMb),
      totalRssGrowthMb: numberOrNull(sample.totalRssGrowthMb),
      maxProcessRssGrowthMb: numberOrNull(sample.maxProcessRssGrowthMb),
      valuesRedacted: true,
    },
    page: {
      pageRole: page.pageRole ?? null,
      pageId: page.pageId ?? null,
      pageEpoch: numberOrNull(page.pageEpoch),
      timeoutMs: numberOrNull(page.timeoutMs),
      responsivenessLatencyMs: numberOrNull(page.responsivenessLatencyMs),
      responsivenessTimeout: page.responsivenessTimeout === true,
      cdpTimeoutCount: numberOrNull(page.cdpTimeoutCount),
      cdpErrorCount: numberOrNull(page.cdpErrorCount),
      effectiveHeapUsedMb: numberOrNull(page.effectiveHeapUsedMb),
      effectiveJsHeapUsedMb: numberOrNull(page.effectiveJsHeapUsedMb),
      heapUsedGrowthMb: numberOrNull(page.heapUsedGrowthMb),
      jsHeapUsedGrowthMb: numberOrNull(page.jsHeapUsedGrowthMb),
      baselineCapturedAt: page.baselineCapturedAt ?? null,
      valuesRedacted: true,
    },
    browserKill: {
      ok: browserKill.ok === true,
      pending: browserKill.pending === true,
      skipped: browserKill.skipped === true,
      reason: browserKill.reason ?? null,
      pid: numberOrNull(browserKill.pid),
      gracefulSignal: browserKill.gracefulSignal ?? null,
      forceSignal: browserKill.forceSignal ?? null,
      gracefulSent: browserKill.gracefulSent === true,
      forceSent: browserKill.forceSent === true,
      exitedAfterGrace: browserKill.exitedAfterGrace === true,
      exitedAfterForce: browserKill.exitedAfterForce === true,
      valuesRedacted: true,
    },
    valuesRedacted: true,
  };
}

function buildBrowserProcessFindings(report, runtimeAlerts = null) {
  const summary = report?.summary || {};
  const findings = [];
  const blockerEvents = Array.isArray(report?.blockerEvents) ? report.blockerEvents : [];
  if (blockerEvents.length > 0) {
    const first = blockerEvents[0] || {};
    findings.push({
      id: "frontend-browser-freeze-runner-blocker",
      severity: "red",
      summary: "web-probe runner matched YAML browserFreezePolicy, killed/stopped Chromium, and failed the observer run; do not clear this by refresh or fallback",
      count: blockerEvents.length,
      blocking: true,
      rootCause: first.rootCause ?? "frontend_browser_freeze_policy_blocker",
      rootCauseStatus: "confirmed-from-runner-browser-freeze-policy",
      rootCauseConfidence: "high",
      policySource: first.policySource ?? "config/hwlab-node-lanes.yaml#webProbe.browserFreezePolicy",
      fallbackAllowed: false,
      observerRefreshAllowed: false,
      browserKilled: first.browserKill ?? null,
      events: blockerEvents.slice(0, 20),
      valuesRedacted: true,
    });
  }
  if (!summary || Number(summary.sampleCount ?? 0) <= 0) return findings;
  const rootCauseSignals = browserRootCauseSignals(report, runtimeAlerts);
  const pageEvents = Array.isArray(report.latestPageEvents) ? report.latestPageEvents : [];
  const maxEffectiveHeapEvent = maxByNumber(pageEvents, (item) => Math.max(Number(item.effectiveHeapUsedMb ?? 0), Number(item.effectiveJsHeapUsedMb ?? 0)));
  const maxEffectiveHeapMb = maxEffectiveHeapEvent ? Math.max(Number(maxEffectiveHeapEvent.effectiveHeapUsedMb ?? 0), Number(maxEffectiveHeapEvent.effectiveJsHeapUsedMb ?? 0)) : 0;
  if (maxEffectiveHeapMb >= alertThresholds.browserProcessRssRedMb) {
    findings.push({
      id: "frontend-browser-memory-rss-red",
      severity: "red",
      summary: "Page effective memory exceeded YAML red threshold after subtracting page baseline; process RSS remains diagnostic evidence only",
      maxEffectiveHeapMb,
      processRssRedMb: alertThresholds.browserProcessRssRedMb,
      memoryRedPolicyScope: "per-page-effective-memory",
      maxEffectiveHeapEvent,
      maxTotalRssSample: report.maxTotalRssSample,
      maxProcessRssSample: report.maxProcessRssSample,
      rootCause: "frontend_browser_page_effective_memory_pressure",
      rootCauseStatus: "confirmed-from-runner-page-effective-memory",
      rootCauseConfidence: "high",
      rootCauseSignals,
      fallbackAllowed: false,
      valuesRedacted: true,
    });
  }
  const maxEffectiveGrowthEvent = maxByNumber(pageEvents, (item) => Math.max(Number(item.heapUsedGrowthMb ?? 0), Number(item.jsHeapUsedGrowthMb ?? 0)));
  const maxEffectiveGrowthMb = maxEffectiveGrowthEvent ? Math.max(Number(maxEffectiveGrowthEvent.heapUsedGrowthMb ?? 0), Number(maxEffectiveGrowthEvent.jsHeapUsedGrowthMb ?? 0)) : 0;
  if (maxEffectiveGrowthMb >= alertThresholds.browserRssGrowthRedMb) {
    findings.push({
      id: "frontend-browser-memory-growth-red",
      severity: "red",
      summary: "Page effective memory grew beyond YAML window budget; this matches the reported freeze pattern without counting multi-page startup RSS",
      maxEffectiveGrowthMb,
      growthRedMb: alertThresholds.browserRssGrowthRedMb,
      windowMs: alertThresholds.browserRssGrowthWindowMs,
      memoryRedPolicyScope: "per-page-effective-memory",
      maxEffectiveGrowthEvent,
      maxGrowthSample: report.maxGrowthSample,
      maxProcessGrowthSample: report.maxProcessGrowthSample,
      rootCause: "frontend_browser_page_memory_leak_or_unbounded_render_growth",
      rootCauseStatus: "confirmed-from-runner-page-effective-memory-growth",
      rootCauseConfidence: "high",
      rootCauseSignals,
      fallbackAllowed: false,
      valuesRedacted: true,
    });
  }
  const responsivenessEvents = Array.isArray(report.responsivenessEvents) ? report.responsivenessEvents : [];
  const severeLatencyEvents = responsivenessEvents.filter((item) => item.responsivenessTimeout !== true && Number(item.responsivenessLatencyMs ?? 0) >= alertThresholds.playwrightResponsivenessRedMs);
  const responsivenessTimeoutBurst = firstBurst(
    responsivenessEvents.filter((item) => item.responsivenessTimeout === true),
    alertThresholds.playwrightResponsivenessTimeoutRedCount,
    alertThresholds.domEvaluateTimeoutRedWindowMs,
  );
  if (severeLatencyEvents.length > 0 || responsivenessTimeoutBurst) {
    const events = severeLatencyEvents.length > 0 ? severeLatencyEvents : responsivenessTimeoutBurst;
    findings.push({
      id: "frontend-playwright-responsiveness-red",
      severity: "red",
      summary: "Playwright/CDP responsiveness probe exceeded YAML budget; treat the browser page as frozen instead of refreshing or falling back",
      count: events.length,
      latencyRedMs: alertThresholds.playwrightResponsivenessRedMs,
      timeoutThresholdCount: alertThresholds.playwrightResponsivenessTimeoutRedCount,
      windowMs: alertThresholds.domEvaluateTimeoutRedWindowMs,
      events: events.slice(0, 20).map(browserProcessEventRef),
      rootCause: "frontend_browser_page_unresponsive_to_playwright",
      rootCauseStatus: "confirmed-from-cdp-runtime-evaluate",
      rootCauseConfidence: "high",
      rootCauseSignals,
      fallbackAllowed: false,
      valuesRedacted: true,
    });
  }
  const cdpTimeoutEvents = Array.isArray(report.cdpTimeoutEvents) ? report.cdpTimeoutEvents : [];
  const cdpTimeoutBurst = firstBurst(cdpTimeoutEvents, alertThresholds.cdpMetricsTimeoutRedCount, alertThresholds.domEvaluateTimeoutRedWindowMs);
  if (cdpTimeoutBurst) {
    findings.push({
      id: "frontend-cdp-metrics-timeout-red",
      severity: "red",
      summary: "CDP browser metrics timed out repeatedly; the sentinel has direct browser-side evidence of a hung page/runtime",
      count: cdpTimeoutBurst.length,
      thresholdCount: alertThresholds.cdpMetricsTimeoutRedCount,
      windowMs: alertThresholds.domEvaluateTimeoutRedWindowMs,
      events: cdpTimeoutBurst.slice(0, 20).map(browserProcessEventRef),
      rootCause: "frontend_browser_cdp_metrics_unresponsive",
      rootCauseStatus: "confirmed-from-cdp-metrics-timeouts",
      rootCauseConfidence: "high",
      rootCauseSignals,
      fallbackAllowed: false,
      valuesRedacted: true,
    });
  }
  return findings;
}

function browserRootCauseSignals(report, runtimeAlerts) {
  const browserSummary = report?.summary || {};
  const runtimeSummary = runtimeAlerts?.summary || {};
  const sampleCount = Number(browserSummary.sampleCount ?? 0);
  const sessionListReadCount = Number(runtimeSummary.workbenchSessionListReadCount ?? 0);
  const traceEventsReadCount = Number(runtimeSummary.workbenchTraceEventsReadCount ?? 0);
  const webPerformanceBeaconFailureCount = Number(runtimeSummary.webPerformanceBeaconFailureCount ?? 0);
  const eventSourceFailureCount = Number(runtimeSummary.workbenchEventSourceFailureCount ?? 0);
  const suspectedFrontendRefreshStorm = sessionListReadCount >= Math.max(20, sampleCount * 2);
  return {
    suspectedFrontendRefreshStorm,
    sessionListReadCount,
    traceEventsReadCount,
    webPerformanceBeaconFailureCount,
    eventSourceFailureCount,
    requestFailedCount: runtimeSummary.significantRequestFailedCount ?? runtimeSummary.requestFailedCount ?? 0,
    httpErrorCount: runtimeSummary.httpErrorCount ?? 0,
    topRequestFailedPaths: (runtimeAlerts?.networkSignificantRequestFailedByPath ?? runtimeAlerts?.networkRequestFailedByPath ?? []).slice(0, 5),
    topHttpErrorPaths: (runtimeAlerts?.networkHttpErrorsByPath ?? []).slice(0, 5),
    note: suspectedFrontendRefreshStorm
      ? "suspected frontend refresh storm: session list reads exceed the sample-derived budget during a browser red finding"
      : "root-cause signals are included so memory/responsiveness/CDP red findings can be correlated without manual grep",
    valuesRedacted: true,
  };
}

function computeBrowserProcessGrowth(samples, windowMs) {
  const budgetMs = Math.max(1000, Number(windowMs || 0));
  const sorted = (samples || []).filter((item) => Number.isFinite(item.tsMs)).sort((a, b) => a.tsMs - b.tsMs);
  return sorted.map((item, index) => {
    const candidates = sorted.slice(0, index + 1).filter((candidate) => item.tsMs - candidate.tsMs <= budgetMs);
    const totalBaseline = minByNumber(candidates, (candidate) => candidate.totalRssBytes);
    const processBaseline = minByNumber(candidates, (candidate) => candidate.maxProcessRssBytes);
    const totalGrowth = Number(item.totalRssBytes || 0) - Number(totalBaseline?.totalRssBytes || 0);
    const processGrowth = Number(item.maxProcessRssBytes || 0) - Number(processBaseline?.maxProcessRssBytes || 0);
    return {
      ...item,
      windowMs: budgetMs,
      totalBaselineAt: totalBaseline?.ts ?? null,
      processBaselineAt: processBaseline?.ts ?? null,
      totalRssGrowthBytes: totalGrowth,
      totalRssGrowthMb: bytesToMb(totalGrowth),
      maxProcessRssGrowthBytes: processGrowth,
      maxProcessRssGrowthMb: bytesToMb(processGrowth),
      valuesRedacted: true,
    };
  });
}

function browserProcessEventRef(item) {
  return {
    ts: item?.ts ?? null,
    seq: item?.seq ?? null,
    sampleSeq: item?.sampleSeq ?? null,
    commandId: item?.commandId ?? null,
    pageRole: item?.pageRole ?? null,
    pageId: item?.pageId ?? null,
    pageEpoch: item?.pageEpoch ?? null,
    timeoutMs: item?.timeoutMs ?? null,
    responsivenessLatencyMs: item?.responsivenessLatencyMs ?? item?.latencyMs ?? null,
    responsivenessTimeout: item?.responsivenessTimeout === true,
    cdpTimeoutCount: item?.cdpTimeoutCount ?? null,
    method: item?.method ?? null,
    errorMessage: item?.errorMessage ?? null,
    valuesRedacted: true,
  };
}

function compactBrowserProcessRow(item) {
  if (!item || typeof item !== "object") return null;
  return {
    pid: item.pid ?? null,
    role: item.role ?? null,
    name: item.name ?? null,
    rssMb: bytesToMb(item.rssBytes),
    vmSizeMb: bytesToMb(item.vmSizeBytes),
    commandHash: item.commandHash ?? null,
    valuesRedacted: true,
  };
}

function browserMetricNumber(value) {
  const numeric = Number(value);
  return Number.isFinite(numeric) ? numeric : null;
}

function bytesToMb(value) {
  const numeric = Number(value);
  if (!Number.isFinite(numeric)) return null;
  return Number((numeric / 1024 / 1024).toFixed(1));
}

function maxByNumber(items, getter) {
  let selected = null;
  let selectedValue = Number.NEGATIVE_INFINITY;
  for (const item of Array.isArray(items) ? items : []) {
    const value = Number(getter(item));
    if (!Number.isFinite(value)) continue;
    if (!selected || value > selectedValue) {
      selected = item;
      selectedValue = value;
    }
  }
  return selected;
}

function minByNumber(items, getter) {
  let selected = null;
  let selectedValue = Number.POSITIVE_INFINITY;
  for (const item of Array.isArray(items) ? items : []) {
    const value = Number(getter(item));
    if (!Number.isFinite(value)) continue;
    if (!selected || value < selectedValue) {
      selected = item;
      selectedValue = value;
    }
  }
  return selected;
}

function safeReportUrl(value) {
  if (!value) return null;
  try {
    const url = new URL(String(value));
    return url.origin + url.pathname;
  } catch {
    return limitText(String(value), 200);
  }
}

function frontendFreezeErrorEvent(item, promptTimes) {
  const details = objectValue(item?.error?.details);
  const message = String(item?.error?.message ?? item?.message ?? item?.error ?? "");
  const type = String(item?.type || "");
  const tsMs = Date.parse(String(item?.ts || ""));
  if (!Number.isFinite(tsMs)) return null;
  const kind = classifyFrontendFreezeError(type, message);
  if (!kind) return null;
  return {
    ts: item.ts ?? null,
    tsMs,
    promptIndex: promptIndexForTs(promptTimes, item.ts),
    kind,
    type: item.type ?? null,
    pageRole: stringOrNull(item?.pageRole) ?? stringOrNull(details.pageRole) ?? pageRoleFromErrorType(type),
    pageId: stringOrNull(item?.pageId) ?? stringOrNull(details.pageId),
    routeSessionId: stringOrNull(item?.routeSessionId) ?? stringOrNull(details.routeSessionId),
    activeSessionId: stringOrNull(item?.activeSessionId) ?? stringOrNull(details.activeSessionId),
    commandId: stringOrNull(item?.commandId) ?? stringOrNull(details.commandId),
    sampleSeq: numberOrNull(item?.sampleSeq ?? details.sampleSeq),
    timeoutMs: timeoutMsFromMessage(message),
    messageHash: message ? sha256(message) : null,
    preview: limitText(message, 240),
    valuesRedacted: true,
  };
}

function pageRoleFromErrorType(type) {
  const value = String(type || "");
  if (/^control-/iu.test(value)) return "control";
  if (/^observer-/iu.test(value)) return "observer";
  return null;
}

function classifyFrontendFreezeError(type, message) {
  const value = String(message || "");
  if (/sampleOnePage\s+DOM\s+evaluate\s+exceeded/iu.test(value) && /(?:control|observer)-sample-error/iu.test(type)) return "dom-evaluate-timeout";
  if (/screenshot|captureScreenshot|page\.screenshot/iu.test(type + " " + value) && /timeout|timed\s*out|exceeded/iu.test(value)) return "screenshot-timeout";
  if (/pageerror|uncaught|unhandledrejection/iu.test(type) || /^(?:Error|TypeError|ReferenceError|RangeError|SyntaxError):/u.test(value)) return "page-error";
  return null;
}

function firstBurst(events, thresholdCount, windowMs) {
  const count = Math.max(1, Math.floor(Number(thresholdCount || 0)));
  const budgetMs = Math.max(1, Number(windowMs || 0));
  const sorted = (events || []).filter((item) => Number.isFinite(item?.tsMs)).sort((a, b) => a.tsMs - b.tsMs);
  if (sorted.length < count) return null;
  for (let start = 0; start <= sorted.length - count; start += 1) {
    const end = start + count - 1;
    if (sorted[end].tsMs - sorted[start].tsMs <= budgetMs) return sorted.slice(start, end + 1);
  }
  return null;
}

function frontendFreezeBurstFinding({ id, summary, burst, thresholdCount, windowMs, pageRole }) {
  const first = burst[0];
  const last = burst[burst.length - 1];
  const pageIds = uniqueStrings(burst.map((item) => item.pageId));
  const routeSessionIds = uniqueStrings(burst.map((item) => item.routeSessionId));
  const activeSessionIds = uniqueStrings(burst.map((item) => item.activeSessionId));
  return {
    id,
    severity: "red",
    summary,
    count: burst.length,
    thresholdCount,
    windowMs,
    firstAt: first?.ts ?? null,
    lastAt: last?.ts ?? null,
    pageRole,
    pageIds,
    routeSessionIds,
    activeSessionIds,
    timeoutMsMax: maxPresentNumber(burst.map((item) => item.timeoutMs)),
    rootCause: "frontend_page_freeze_or_runtime_exception",
    rootCauseStatus: "confirmed-from-browser-observer-errors",
    rootCauseConfidence: "high",
    fallbackAllowed: false,
    observerRefreshMayNotClear: true,
    nextAction: "Keep this run red; do not auto-refresh, fallback, or mark healthy until OTel/browser evidence explains why the page stopped responding.",
    events: burst.map((item) => ({
      ts: item.ts,
      promptIndex: item.promptIndex,
      type: item.type,
      pageRole: item.pageRole,
      pageId: item.pageId,
      routeSessionId: item.routeSessionId,
      activeSessionId: item.activeSessionId,
      commandId: item.commandId,
      sampleSeq: item.sampleSeq,
      timeoutMs: item.timeoutMs,
      messageHash: item.messageHash,
      preview: item.preview,
      valuesRedacted: true,
    })),
    valuesRedacted: true,
  };
}

function stopCommandWindows(control) {
  return (control || [])
    .filter((item) => /^(?:stop|forceStop|cancel|close)$/iu.test(String(item?.type || item?.command || "")))
    .map((item) => {
      const tsMs = Date.parse(String(item?.ts || ""));
      return Number.isFinite(tsMs) ? { fromMs: tsMs - 1000, toMs: tsMs + 10000 } : null;
    })
    .filter(Boolean);
}

function errorInsideStopWindow(event, windows) {
  return (windows || []).some((window) => event.tsMs >= window.fromMs && event.tsMs <= window.toMs);
}

function timeoutMsFromMessage(value) {
  const match = String(value || "").match(/\b(?:exceeded|timeout|timed\s*out\s*after)\s+(\d{2,})\s*ms\b/iu)
    || String(value || "").match(/\b(\d{2,})\s*ms\b/iu);
  return match ? Number(match[1]) : null;
}

function uniqueStrings(values) {
  return Array.from(new Set((values || []).filter((item) => typeof item === "string" && item.length > 0))).slice(0, 12);
}

function maxPresentNumber(values) {
  const numbers = (values || []).filter((item) => item !== null && item !== undefined && Number.isFinite(Number(item))).map((item) => Number(item));
  return numbers.length > 0 ? Math.max(...numbers) : null;
}
`;
}