// SPEC: pikasTech/unidesk#1436 WEB-PROBE performance analyzer.
// Responsibility: Source string for offline frontend long-task/LoAF/profile hotspot analysis.

export function nodeWebObserveAnalyzerPerformanceSource(): string {
  return String.raw`
var frontendPerformanceSourceMapper = null;

async function buildFrontendPerformanceReport(rows, artifacts, samples, network) {
  const sourceRows = Array.isArray(rows) ? rows : [];
  const sourceSamples = Array.isArray(samples) ? samples : [];
  const sourceNetwork = Array.isArray(network) ? network : [];
  const sourceMapState = await buildFrontendPerformanceSourceMapState(artifacts);
  frontendPerformanceSourceMapper = createFrontendPerformanceSourceMapper(sourceMapState.maps);
  const events = [];
  const drainErrors = [];
  const captures = [];
  const scriptGroups = new Map();
  const profileFunctionGroups = new Map();
  const profileStackGroups = new Map();
  for (const row of sourceRows) {
    if (!row || typeof row !== "object") continue;
    if (row.type === "performance-drain-error") {
      drainErrors.push(compactPerformanceDrainError(row));
      continue;
    }
    if (row.type === "performance-capture-completed") {
      const capture = compactPerformanceCapture(row);
      captures.push(capture);
      for (const fn of Array.isArray(row.summary?.topFunctions) ? row.summary.topFunctions : []) mergeProfileFunction(profileFunctionGroups, fn, capture);
      for (const stack of Array.isArray(row.summary?.topStacks) ? row.summary.topStacks : []) mergeProfileStack(profileStackGroups, stack, capture);
      continue;
    }
    if (row.type !== "performance-event") continue;
    const perf = row.performance && typeof row.performance === "object" ? row.performance : {};
    const event = compactPerformanceEventRow(row, perf);
    if (!event.kind) continue;
    events.push(event);
    for (const script of Array.isArray(perf.scripts) ? perf.scripts : []) mergeLoafScript(scriptGroups, script, event);
  }
  await attachCpuProfileTimelines(captures);
  const longTasks = events.filter((item) => item.kind === "longtask");
  const loafs = events.filter((item) => item.kind === "long-animation-frame");
  const gaps = events.filter((item) => item.kind === "event-loop-gap");
  const scriptHotspots = Array.from(scriptGroups.values())
    .map(finalizeScriptHotspot)
    .sort((left, right) => Number(right.totalDurationMs ?? 0) - Number(left.totalDurationMs ?? 0) || Number(right.count ?? 0) - Number(left.count ?? 0))
    .slice(0, 40);
  const profileHotspots = Array.from(profileFunctionGroups.values())
    .map(finalizeProfileFunctionHotspot)
    .sort((left, right) => Number(right.selfTimeMs ?? 0) - Number(left.selfTimeMs ?? 0) || Number(right.totalTimeMs ?? 0) - Number(left.totalTimeMs ?? 0))
    .slice(0, 40);
  const profileStacks = Array.from(profileStackGroups.values())
    .map(finalizeProfileStackHotspot)
    .sort((left, right) => Number(right.selfTimeMs ?? 0) - Number(left.selfTimeMs ?? 0))
    .slice(0, 30);
  const performanceWindows = buildFrontendPerformanceWindows({ events, captures, profileHotspots, profileStacks, scriptHotspots, samples: sourceSamples, network: sourceNetwork });
  const sourceAttribution = buildFrontendSourceAttribution({ scriptHotspots, profileHotspots, profileStacks, sourceMapState });
  const attribution = frontendPerformanceAttributionStatus({ captures, profileHotspots, profileStacks, scriptHotspots, longTasks, loafs, gaps, performanceWindows });
  return {
    summary: {
      rowCount: sourceRows.length,
      eventCount: events.length,
      longTaskCount: longTasks.length,
      longAnimationFrameCount: loafs.length,
      eventLoopGapCount: gaps.length,
      drainErrorCount: drainErrors.length,
      captureCount: captures.length,
      profileHotspotCount: profileHotspots.length,
      scriptHotspotCount: scriptHotspots.length,
      longTaskRedMs: alertThresholds.longTaskRedMs,
      longAnimationFrameRedMs: alertThresholds.longAnimationFrameRedMs,
      eventLoopGapRedMs: alertThresholds.eventLoopGapRedMs,
      maxLongTaskMs: frontendPerformanceMaxNumber(longTasks, (item) => item.durationMs),
      maxLongAnimationFrameMs: frontendPerformanceMaxNumber(loafs, (item) => item.durationMs),
      maxEventLoopGapMs: frontendPerformanceMaxNumber(gaps, (item) => item.durationMs),
      cpuProfileStatus: attribution.cpuProfileStatus,
      attributionMode: attribution.attributionMode,
      noCpuProfile: attribution.noCpuProfile,
      loafOnly: attribution.loafOnly,
      cpuProfileHotspotEvidence: attribution.cpuProfileHotspotEvidence,
      evidenceNote: attribution.evidenceNote,
      windowCorrelationCount: performanceWindows.length,
      cpuProfileWindowCoveredCount: performanceWindows.filter((item) => item.cpuProfileCoverageStatus === "covered").length,
      cpuProfileWindowOverlappedCount: performanceWindows.filter((item) => item.cpuProfileCoverageStatus === "overlapped").length,
      cpuProfileWindowMissedCount: performanceWindows.filter((item) => item.cpuProfileCoverageStatus === "missed").length,
      cpuProfileWindowMissingCount: performanceWindows.filter((item) => item.cpuProfileCoverageStatus === "no-cpu-profile").length,
      sourceMapStatus: sourceAttribution.sourceMapStatus,
      captureArtifacts: performanceCaptureArtifacts(artifacts),
      valuesRedacted: true,
    },
    longTasks: longTasks.sort(descDuration).slice(0, 40),
    longAnimationFrames: loafs.sort(descDuration).slice(0, 40),
    eventLoopGaps: gaps.sort(descDuration).slice(0, 40),
    scriptHotspots,
    profileHotspots,
    profileStacks,
    performanceWindows,
    sourceAttribution,
    captures: captures.slice(-20),
    drainErrors: drainErrors.slice(-20),
    valuesRedacted: true,
  };
}

function buildFrontendPerformanceFindings(report) {
  const findings = [];
  const summary = report?.summary || {};
  const severeLongTasks = (report?.longTasks || []).filter((item) => Number(item.durationMs ?? 0) >= alertThresholds.longTaskRedMs);
  if (severeLongTasks.length > 0) findings.push({
    id: "frontend-longtask-red",
    severity: "red",
    summary: "PerformanceObserver captured long tasks over YAML budget; use LoAF scripts or CPU profile hotspots for function attribution",
    count: severeLongTasks.length,
    budgetMs: alertThresholds.longTaskRedMs,
    maxDurationMs: summary.maxLongTaskMs,
    events: severeLongTasks.slice(0, 20),
    topScripts: (report?.scriptHotspots || []).slice(0, 8),
    topProfileFunctions: (report?.profileHotspots || []).slice(0, 8),
    valuesRedacted: true,
  });
  const severeLoafs = (report?.longAnimationFrames || []).filter((item) => Number(item.durationMs ?? 0) >= alertThresholds.longAnimationFrameRedMs || Number(item.blockingDurationMs ?? 0) >= alertThresholds.longAnimationFrameRedMs);
  if (severeLoafs.length > 0) findings.push({
    id: "frontend-long-animation-frame-red",
    severity: "red",
    summary: "Long Animation Frame entries exceeded YAML budget and include script attribution when Chromium exposes it",
    count: severeLoafs.length,
    budgetMs: alertThresholds.longAnimationFrameRedMs,
    maxDurationMs: summary.maxLongAnimationFrameMs,
    events: severeLoafs.slice(0, 20),
    topScripts: (report?.scriptHotspots || []).slice(0, 12),
    valuesRedacted: true,
  });
  const severeGaps = (report?.eventLoopGaps || []).filter((item) => Number(item.durationMs ?? 0) >= alertThresholds.eventLoopGapRedMs);
  if (severeGaps.length > 0) findings.push({
    id: "frontend-event-loop-gap-red",
    severity: "red",
    summary: "web-probe page-side event loop gap probe observed main-thread stalls over YAML budget",
    count: severeGaps.length,
    budgetMs: alertThresholds.eventLoopGapRedMs,
    maxDurationMs: summary.maxEventLoopGapMs,
    events: severeGaps.slice(0, 20),
    valuesRedacted: true,
  });
  if ((report?.profileHotspots || []).length > 0) findings.push({
    id: "frontend-cpu-profile-hotspots",
    severity: severeLongTasks.length > 0 || severeLoafs.length > 0 || severeGaps.length > 0 ? "red" : "info",
    summary: "CDP CPU profile capture produced function-level hotspots for offline attribution",
    count: report.profileHotspots.length,
    captures: (report?.captures || []).slice(-8),
    topFunctions: report.profileHotspots.slice(0, 12),
    topStacks: (report?.profileStacks || []).slice(0, 8),
    valuesRedacted: true,
  });
  if (summary.noCpuProfile === true && (severeLongTasks.length > 0 || severeLoafs.length > 0 || severeGaps.length > 0)) findings.push({
    id: "frontend-performance-loaf-only-no-cpu-profile",
    severity: "amber",
    summary: "frontend performance evidence is LoAF/LongTask/event-loop only because no completed CPU profile capture is present; do not cite CPU profile hotspots for this run",
    count: 1,
    attributionMode: summary.attributionMode || "loaf-only-no-cpu-profile",
    cpuProfileStatus: summary.cpuProfileStatus || "missing",
    captureCount: summary.captureCount ?? 0,
    windowCorrelations: (report?.performanceWindows || []).slice(0, 8),
    longTaskCount: summary.longTaskCount ?? 0,
    longAnimationFrameCount: summary.longAnimationFrameCount ?? 0,
    eventLoopGapCount: summary.eventLoopGapCount ?? 0,
    topScripts: (report?.scriptHotspots || []).slice(0, 12),
    nextAction: "Run an explicit performanceCapture command and re-run observe analyze before making CPU-profile hotspot claims; existing LoAF scripts remain valid browser-side attribution.",
    valuesRedacted: true,
  });
  if ((report?.drainErrors || []).length > 0) findings.push({
    id: "frontend-performance-probe-drain-errors",
    severity: "amber",
    summary: "page-side performance probe had drain errors; improve probe visibility before relying on absence of long-task events",
    count: report.drainErrors.length,
    errors: report.drainErrors.slice(0, 12),
    valuesRedacted: true,
  });
  return findings;
}

function frontendPerformanceAttributionStatus(input) {
  const captureCount = Array.isArray(input?.captures) ? input.captures.length : 0;
  const profileHotspotCount = Array.isArray(input?.profileHotspots) ? input.profileHotspots.length : 0;
  const profileStackCount = Array.isArray(input?.profileStacks) ? input.profileStacks.length : 0;
  const scriptHotspotCount = Array.isArray(input?.scriptHotspots) ? input.scriptHotspots.length : 0;
  const eventCount =
    (Array.isArray(input?.longTasks) ? input.longTasks.length : 0) +
    (Array.isArray(input?.loafs) ? input.loafs.length : 0) +
    (Array.isArray(input?.gaps) ? input.gaps.length : 0);
  const hasCpuProfile = captureCount > 0;
  const hasCpuProfileHotspots = profileHotspotCount > 0 || profileStackCount > 0;
  const windowRows = Array.isArray(input?.performanceWindows) ? input.performanceWindows : [];
  const coveredWindowCount = windowRows.filter((item) => item?.cpuProfileCoverageStatus === "covered" || item?.cpuProfileCoverageStatus === "overlapped").length;
  const missedWindowCount = windowRows.filter((item) => item?.cpuProfileCoverageStatus === "missed").length;
  if (hasCpuProfile) {
    return {
      cpuProfileStatus: hasCpuProfileHotspots ? (coveredWindowCount > 0 ? "captured-with-window-hotspots" : "captured-hotspots-outside-performance-window") : "captured-no-hotspots",
      attributionMode: missedWindowCount > 0 && coveredWindowCount === 0 ? "cpu-profile-missed-performance-window" : "cpu-profile-and-performance-observer",
      noCpuProfile: false,
      loafOnly: false,
      cpuProfileHotspotEvidence: hasCpuProfileHotspots,
      evidenceNote: hasCpuProfileHotspots
        ? coveredWindowCount > 0
          ? "completed performanceCapture artifacts overlap severe frontend performance windows; attached CPU hotspots are same-capture candidates"
          : "completed performanceCapture artifacts produced CPU profile hotspots, but none overlap the severe frontend performance windows"
        : "completed performanceCapture artifacts exist, but no CPU profile hotspots were extracted",
      valuesRedacted: true,
    };
  }
  return {
    cpuProfileStatus: "missing",
    attributionMode: eventCount > 0 || scriptHotspotCount > 0 ? "loaf-only-no-cpu-profile" : "no-frontend-performance-evidence",
    noCpuProfile: true,
    loafOnly: eventCount > 0 || scriptHotspotCount > 0,
    cpuProfileHotspotEvidence: false,
    evidenceNote: eventCount > 0 || scriptHotspotCount > 0
      ? "LongTask/LoAF/event-loop evidence is present, but no completed performanceCapture CPU profile exists"
      : "no frontend performance events or completed performanceCapture CPU profile exist",
    valuesRedacted: true,
  };
}

function compactPerformanceEventRow(row, perf) {
  const window = performanceEventWindow(row, perf);
  return {
    ts: row.ts ?? null,
    seq: row.seq ?? null,
    sampleSeq: row.sampleSeq ?? null,
    sampleGroupSeq: row.sampleGroupSeq ?? null,
    commandId: row.commandId ?? null,
    pageRole: row.pageRole ?? null,
    pageId: row.pageId ?? null,
    pageEpoch: numberOrNull(row.pageEpoch),
    kind: perf.kind ?? null,
    name: limitText(perf.name ?? "", 120),
    durationMs: numberOrNull(perf.duration),
    blockingDurationMs: numberOrNull(perf.blockingDuration),
    startTime: numberOrNull(perf.startTime),
    thresholdMs: numberOrNull(perf.thresholdMs),
    timeOrigin: numberOrNull(perf.timeOrigin),
    observedAt: numberOrNull(perf.observedAt),
    startEpochMs: window.startEpochMs,
    endEpochMs: window.endEpochMs,
    startAt: window.startAt,
    endAt: window.endAt,
    windowSource: window.source,
    path: limitText(perf.path ?? "", 160),
    url: safeReportUrl(perf.url),
    scriptCount: Array.isArray(perf.scripts) ? perf.scripts.length : 0,
    attributionCount: Array.isArray(perf.attribution) ? perf.attribution.length : 0,
    scripts: (Array.isArray(perf.scripts) ? perf.scripts : []).slice(0, 8).map(compactLoafScript),
    valuesRedacted: true,
  };
}

function compactPerformanceDrainError(row) {
  return {
    ts: row?.ts ?? null,
    sampleSeq: row?.sampleSeq ?? null,
    pageRole: row?.pageRole ?? null,
    pageId: row?.pageId ?? null,
    reason: row?.drain?.reason ?? row?.reason ?? null,
    message: limitText(row?.drain?.error?.message ?? row?.error?.message ?? "", 200),
    valuesRedacted: true,
  };
}

function compactPerformanceCapture(row) {
  const artifact = row.artifact && typeof row.artifact === "object" ? row.artifact : {};
  const summary = row.summary && typeof row.summary === "object" ? row.summary : {};
  const durationMs = numberOrNull(artifact.durationMs ?? summary.durationMs);
  const endEpochMs = performanceTimestampMs(row.ts);
  const startEpochMs = Number.isFinite(endEpochMs) && Number.isFinite(durationMs) ? endEpochMs - Number(durationMs) : null;
  return {
    ts: row.ts ?? null,
    commandId: row.commandId ?? null,
    captureId: row.captureId ?? artifact.captureId ?? null,
    pageRole: row.pageRole ?? artifact.pageRole ?? null,
    pageId: row.pageId ?? artifact.pageId ?? null,
    durationMs,
    startEpochMs,
    endEpochMs,
    startAt: startEpochMs === null ? null : new Date(startEpochMs).toISOString(),
    endAt: endEpochMs === null ? null : new Date(endEpochMs).toISOString(),
    windowSource: startEpochMs === null ? "missing-capture-window" : "completed-event-ts-minus-artifact-duration",
    profileTotalTimeMs: numberOrNull(summary.totalTimeMs),
    profileSampleCount: numberOrNull(summary.sampleCount),
    profileTimelineStatus: "not-loaded",
    profileTimelineSampleCount: null,
    profileTimelineTotalTimeMs: null,
    profileTimelineStartAt: null,
    profileTimelineEndAt: null,
    profileTimeline: null,
    path: artifact.path ?? null,
    summaryPath: artifact.summaryPath ?? null,
    sha256: artifact.sha256 ?? null,
    summarySha256: artifact.summarySha256 ?? null,
    valuesRedacted: true,
  };
}

function compactLoafScript(script) {
  const value = script && typeof script === "object" ? script : {};
  const source = sourceAttributionFor(value.sourceURL, value.sourceFunctionName, value.lineNumber, value.columnNumber, value.sourceCharPosition);
  return {
    invoker: limitText(value.invoker ?? "", 160),
    invokerType: limitText(value.invokerType ?? "", 80),
    sourceURL: safeReportUrl(value.sourceURL),
    sourceFunctionName: limitText(value.sourceFunctionName ?? "", 160),
    sourceFile: source.sourceFile,
    sourceLine: source.sourceLine,
    sourceColumn: source.sourceColumn,
    sourceCharPosition: numberOrNull(value.sourceCharPosition),
    sourceMapStatus: source.sourceMapStatus,
    sourceAttributionMode: source.sourceAttributionMode,
    lineNumber: numberOrNull(value.lineNumber),
    columnNumber: numberOrNull(value.columnNumber),
    startTime: numberOrNull(value.startTime),
    executionStart: numberOrNull(value.executionStart),
    durationMs: numberOrNull(value.duration),
    forcedStyleAndLayoutDurationMs: numberOrNull(value.forcedStyleAndLayoutDuration),
    pauseDurationMs: numberOrNull(value.pauseDuration),
    valuesRedacted: true,
  };
}

function mergeLoafScript(groups, script, event) {
  const compact = compactLoafScript(script);
  const key = loafScriptKey(compact);
  const group = groups.get(key) || { ...compact, key, count: 0, totalDurationMs: 0, maxDurationMs: 0, firstAt: event.ts, lastAt: event.ts, examples: [], valuesRedacted: true };
  const duration = Number(compact.durationMs || 0);
  group.count += 1;
  group.totalDurationMs += duration;
  group.maxDurationMs = Math.max(group.maxDurationMs, duration);
  group.lastAt = event.ts;
  if (group.examples.length < 8) group.examples.push({ ts: event.ts, startAt: event.startAt, endAt: event.endAt, sampleSeq: event.sampleSeq, durationMs: event.durationMs, scriptDurationMs: compact.durationMs, pageRole: event.pageRole, sourceCharPosition: compact.sourceCharPosition, valuesRedacted: true });
  groups.set(key, group);
}

function loafScriptKey(script) {
  if (!script || typeof script !== "object") return "";
  return [script.sourceFunctionName || script.invoker || "(anonymous)", script.sourceURL || "", script.lineNumber ?? "", script.columnNumber ?? ""].join("@");
}

function finalizeScriptHotspot(group) {
  return {
    ...group,
    totalDurationMs: roundMs(group.totalDurationMs),
    maxDurationMs: roundMs(group.maxDurationMs),
    valuesRedacted: true,
  };
}

function mergeProfileFunction(groups, fn, capture) {
  const value = fn && typeof fn === "object" ? fn : {};
  const source = sourceAttributionFor(value.url, value.functionName, value.lineNumber, value.columnNumber, null);
  const key = [value.functionName || "(anonymous)", value.url || value.scriptId || "", value.lineNumber ?? "", value.columnNumber ?? ""].join("@");
  const group = groups.get(key) || { functionName: value.functionName || "(anonymous)", url: safeReportUrl(value.url), scriptId: value.scriptId ?? null, sourceFile: source.sourceFile, sourceLine: source.sourceLine, sourceColumn: source.sourceColumn, sourceMapStatus: source.sourceMapStatus, sourceAttributionMode: source.sourceAttributionMode, lineNumber: numberOrNull(value.lineNumber), columnNumber: numberOrNull(value.columnNumber), key, captureCount: 0, sampleCount: 0, selfTimeMs: 0, totalTimeMs: 0, maxSelfTimeMs: 0, captures: [], valuesRedacted: true };
  const selfTime = Number(value.selfTimeMs || 0);
  const totalTime = Number(value.totalTimeMs || 0);
  group.captureCount += 1;
  group.sampleCount += Number(value.sampleCount || 0);
  group.selfTimeMs += selfTime;
  group.totalTimeMs += totalTime;
  group.maxSelfTimeMs = Math.max(group.maxSelfTimeMs, selfTime);
  if (group.captures.length < 8) group.captures.push({ captureId: capture.captureId, commandId: capture.commandId, selfTimeMs: roundMs(selfTime), totalTimeMs: roundMs(totalTime), valuesRedacted: true });
  groups.set(key, group);
}

function finalizeProfileFunctionHotspot(group) {
  return {
    ...group,
    selfTimeMs: roundMs(group.selfTimeMs),
    totalTimeMs: roundMs(group.totalTimeMs),
    maxSelfTimeMs: roundMs(group.maxSelfTimeMs),
    valuesRedacted: true,
  };
}

function mergeProfileStack(groups, stack, capture) {
  const value = stack && typeof stack === "object" ? stack : {};
  const key = String(value.key || "").slice(0, 800);
  if (!key) return;
  const frames = Array.isArray(value.frames) ? value.frames.slice(-10).map(annotateProfileFrameSource) : [];
  const group = groups.get(key) || { key, sampleCount: 0, selfTimeMs: 0, maxSelfTimeMs: 0, leaf: annotateProfileFrameSource(value.leaf), frames, captures: [], valuesRedacted: true };
  const selfTime = Number(value.selfTimeMs || 0);
  group.sampleCount += Number(value.sampleCount || 0);
  group.selfTimeMs += selfTime;
  group.maxSelfTimeMs = Math.max(group.maxSelfTimeMs, selfTime);
  if (group.captures.length < 6) group.captures.push({ captureId: capture.captureId, commandId: capture.commandId, selfTimeMs: roundMs(selfTime), valuesRedacted: true });
  groups.set(key, group);
}

function finalizeProfileStackHotspot(group) {
  return {
    ...group,
    selfTimeMs: roundMs(group.selfTimeMs),
    maxSelfTimeMs: roundMs(group.maxSelfTimeMs),
    valuesRedacted: true,
  };
}

function performanceCaptureArtifacts(artifacts) {
  return (Array.isArray(artifacts) ? artifacts : [])
    .filter((item) => item && item.kind === "performance-cpu-profile")
    .slice(-20)
    .map((item) => ({ ts: item.ts ?? null, captureId: item.captureId ?? null, commandId: item.commandId ?? null, path: item.path ?? null, summaryPath: item.summaryPath ?? null, sha256: item.sha256 ?? null, summarySha256: item.summarySha256 ?? null, valuesRedacted: true }));
}

async function attachCpuProfileTimelines(captures) {
  for (const capture of Array.isArray(captures) ? captures : []) {
    const profilePath = typeof capture?.path === "string" && capture.path ? capture.path : null;
    if (!profilePath) {
      capture.profileTimelineStatus = "missing-profile-path";
      continue;
    }
    const profile = await readJson(profilePath);
    const timeline = buildCpuProfileSampleTimeline(profile, capture);
    capture.profileTimelineStatus = timeline.status;
    capture.profileTimelineSampleCount = timeline.sampleCount;
    capture.profileTimelineTotalTimeMs = timeline.totalTimeMs;
    capture.profileTimelineStartAt = timeline.startAt;
    capture.profileTimelineEndAt = timeline.endAt;
    capture.profileTimeline = timeline.samples;
  }
}

function buildCpuProfileSampleTimeline(profile, capture) {
  if (!profile || typeof profile !== "object") return emptyCpuProfileTimeline("profile-read-failed");
  const nodes = Array.isArray(profile.nodes) ? profile.nodes : [];
  const sampleIds = Array.isArray(profile.samples) ? profile.samples : [];
  if (nodes.length === 0 || sampleIds.length === 0) return emptyCpuProfileTimeline("profile-has-no-samples");
  const byId = new Map();
  const parentById = new Map();
  for (const node of nodes) {
    const id = Number(node?.id);
    if (!Number.isFinite(id)) continue;
    byId.set(id, node);
    for (const childId of Array.isArray(node?.children) ? node.children : []) {
      const child = Number(childId);
      if (Number.isFinite(child)) parentById.set(child, id);
    }
  }
  const profileStart = Number(profile.startTime);
  const profileEnd = Number(profile.endTime);
  const profileDurationMs = Number.isFinite(profileStart) && Number.isFinite(profileEnd) && profileEnd > profileStart ? (profileEnd - profileStart) / 1000 : null;
  const captureStart = Number(capture?.startEpochMs);
  const captureEnd = Number(capture?.endEpochMs);
  const baseEpochMs = Number.isFinite(captureStart)
    ? captureStart
    : Number.isFinite(captureEnd) && Number.isFinite(profileDurationMs)
      ? captureEnd - Number(profileDurationMs)
      : null;
  if (!Number.isFinite(baseEpochMs)) return emptyCpuProfileTimeline("missing-capture-timebase");
  const deltas = Array.isArray(profile.timeDeltas) ? profile.timeDeltas : [];
  const fallbackDeltaMs = Number.isFinite(profileDurationMs) && sampleIds.length > 0 ? Number(profileDurationMs) / sampleIds.length : 0;
  const samples = [];
  let cursor = Number(baseEpochMs);
  for (let index = 0; index < sampleIds.length; index += 1) {
    const nodeId = Number(sampleIds[index]);
    const rawDelta = Number(deltas[index]);
    const durationMs = Number.isFinite(rawDelta) && rawDelta > 0 ? rawDelta / 1000 : fallbackDeltaMs;
    const startEpochMs = cursor;
    const endEpochMs = cursor + (Number.isFinite(durationMs) && durationMs > 0 ? durationMs : 0);
    cursor = endEpochMs;
    const frames = cpuProfileFramesForNode(nodeId, byId, parentById).map(annotateProfileFrameSource).filter(Boolean);
    samples.push({
      index,
      nodeId: Number.isFinite(nodeId) ? nodeId : null,
      startEpochMs: roundMs(startEpochMs),
      endEpochMs: roundMs(endEpochMs),
      durationMs: roundMs(endEpochMs - startEpochMs),
      leaf: frames[frames.length - 1] || null,
      frames,
      valuesRedacted: true,
    });
  }
  const totalTimeMs = samples.reduce((sum, sample) => sum + Number(sample.durationMs || 0), 0);
  const startAt = samples.length > 0 ? new Date(Number(samples[0].startEpochMs)).toISOString() : null;
  const endAt = samples.length > 0 ? new Date(Number(samples[samples.length - 1].endEpochMs)).toISOString() : null;
  return {
    status: "loaded",
    sampleCount: samples.length,
    totalTimeMs: roundMs(totalTimeMs),
    startAt,
    endAt,
    samples,
    valuesRedacted: true,
  };
}

function emptyCpuProfileTimeline(status) {
  return { status, sampleCount: 0, totalTimeMs: null, startAt: null, endAt: null, samples: [], valuesRedacted: true };
}

function cpuProfileFramesForNode(nodeId, byId, parentById) {
  const frames = [];
  const seen = new Set();
  let current = nodeId;
  while (Number.isFinite(current) && byId.has(current) && !seen.has(current)) {
    seen.add(current);
    const node = byId.get(current);
    const callFrame = node?.callFrame && typeof node.callFrame === "object" ? node.callFrame : {};
    frames.push(compactCpuProfileTimelineFrame(callFrame, node));
    current = parentById.get(current);
  }
  return frames.reverse();
}

function compactCpuProfileTimelineFrame(callFrame, node) {
  return {
    functionName: limitText(callFrame?.functionName || "(anonymous)", 160),
    url: safeReportUrl(callFrame?.url || ""),
    scriptId: callFrame?.scriptId ?? node?.callFrame?.scriptId ?? null,
    lineNumber: numberOrNull(callFrame?.lineNumber),
    columnNumber: numberOrNull(callFrame?.columnNumber),
    valuesRedacted: true,
  };
}

function sameWindowProfileEvidence(event, capture, input) {
  const timeline = Array.isArray(capture?.profileTimeline) ? capture.profileTimeline : [];
  const eventStart = Number(event?.startEpochMs);
  const eventEnd = Number(event?.endEpochMs);
  if (!capture) return null;
  if (timeline.length === 0 || ![eventStart, eventEnd].every(Number.isFinite)) {
    return {
      captureId: capture.captureId ?? null,
      commandId: capture.commandId ?? null,
      evidenceScope: "same-capture-aggregate-context",
      timelineStatus: capture.profileTimelineStatus || "missing-profile-timeline",
      topFunctions: (Array.isArray(input?.profileHotspots) ? input.profileHotspots : []).slice(0, 5),
      topStacks: (Array.isArray(input?.profileStacks) ? input.profileStacks : []).slice(0, 3),
      note: "CPU profile sample timeline is unavailable; hotspot rows are capture-level context, not same-window evidence.",
      valuesRedacted: true,
    };
  }
  const functionGroups = new Map();
  const stackGroups = new Map();
  let sampleCount = 0;
  let totalTimeMs = 0;
  for (const sample of timeline) {
    const start = Number(sample?.startEpochMs);
    const end = Number(sample?.endEpochMs);
    if (![start, end].every(Number.isFinite)) continue;
    const overlapMs = Math.max(0, Math.min(end, eventEnd) - Math.max(start, eventStart));
    if (overlapMs <= 0) continue;
    sampleCount += 1;
    totalTimeMs += overlapMs;
    const frames = Array.isArray(sample?.frames) ? sample.frames : [];
    const leaf = sample?.leaf || frames[frames.length - 1] || null;
    mergeWindowProfileFunction(functionGroups, leaf, overlapMs, overlapMs);
    for (const frame of frames) mergeWindowProfileFunction(functionGroups, frame, 0, overlapMs);
    mergeWindowProfileStack(stackGroups, frames, leaf, overlapMs);
  }
  const topFunctions = Array.from(functionGroups.values())
    .map(finalizeWindowProfileFunction)
    .sort((left, right) => Number(right.selfTimeMs ?? 0) - Number(left.selfTimeMs ?? 0) || Number(right.totalTimeMs ?? 0) - Number(left.totalTimeMs ?? 0))
    .slice(0, 8);
  const topStacks = Array.from(stackGroups.values())
    .map(finalizeWindowProfileStack)
    .sort((left, right) => Number(right.selfTimeMs ?? 0) - Number(left.selfTimeMs ?? 0))
    .slice(0, 5);
  return {
    captureId: capture.captureId ?? null,
    commandId: capture.commandId ?? null,
    evidenceScope: "same-window-cpu-samples",
    timelineStatus: sampleCount > 0 ? "window-samples" : "no-window-samples",
    sampleCount,
    totalTimeMs: roundMs(totalTimeMs),
    windowStartAt: Number.isFinite(eventStart) ? new Date(eventStart).toISOString() : null,
    windowEndAt: Number.isFinite(eventEnd) ? new Date(eventEnd).toISOString() : null,
    topFunctions,
    topStacks,
    valuesRedacted: true,
  };
}

function mergeWindowProfileFunction(groups, frame, selfTimeMs, totalTimeMs) {
  if (!frame || typeof frame !== "object") return;
  const source = frame.sourceMapStatus ? {
    sourceFile: frame.sourceFile ?? sourceFileFromUrl(frame.url),
    sourceLine: frame.sourceLine ?? numberOrNull(frame.lineNumber),
    sourceColumn: frame.sourceColumn ?? numberOrNull(frame.columnNumber),
    sourceMapStatus: frame.sourceMapStatus,
    sourceAttributionMode: frame.sourceAttributionMode ?? "browser-raw-url-line-column",
  } : sourceAttributionFor(frame.url, frame.functionName, frame.lineNumber, frame.columnNumber, null);
  const key = [frame.functionName || "(anonymous)", frame.url || frame.scriptId || "", frame.lineNumber ?? "", frame.columnNumber ?? ""].join("@");
  const group = groups.get(key) || {
    functionName: limitText(frame.functionName || "(anonymous)", 160),
    url: safeReportUrl(frame.url || ""),
    scriptId: frame.scriptId ?? null,
    sourceFile: source.sourceFile,
    sourceLine: source.sourceLine,
    sourceColumn: source.sourceColumn,
    sourceMapStatus: source.sourceMapStatus,
    sourceAttributionMode: source.sourceAttributionMode,
    lineNumber: numberOrNull(frame.lineNumber),
    columnNumber: numberOrNull(frame.columnNumber),
    sampleCount: 0,
    selfTimeMs: 0,
    totalTimeMs: 0,
    valuesRedacted: true,
  };
  group.sampleCount += selfTimeMs > 0 ? 1 : 0;
  group.selfTimeMs += Number(selfTimeMs || 0);
  group.totalTimeMs += Number(totalTimeMs || 0);
  groups.set(key, group);
}

function finalizeWindowProfileFunction(group) {
  return { ...group, selfTimeMs: roundMs(group.selfTimeMs), totalTimeMs: roundMs(group.totalTimeMs), valuesRedacted: true };
}

function mergeWindowProfileStack(groups, frames, leaf, selfTimeMs) {
  const stackFrames = Array.isArray(frames) ? frames.filter(Boolean) : [];
  if (stackFrames.length === 0) return;
  const key = stackFrames.map((frame) => [frame.functionName || "(anonymous)", frame.url || frame.scriptId || "", frame.lineNumber ?? "", frame.columnNumber ?? ""].join("@")).join(" <- ");
  const group = groups.get(key) || { key, leaf: annotateProfileFrameSource(leaf), frames: stackFrames.slice(-10).map(annotateProfileFrameSource), sampleCount: 0, selfTimeMs: 0, valuesRedacted: true };
  group.sampleCount += 1;
  group.selfTimeMs += Number(selfTimeMs || 0);
  groups.set(key, group);
}

function finalizeWindowProfileStack(group) {
  return { ...group, selfTimeMs: roundMs(group.selfTimeMs), valuesRedacted: true };
}

function buildFrontendPerformanceWindows(input) {
  const aggregatedLoafHotspotKeys = new Set(
    (Array.isArray(input?.scriptHotspots) ? input.scriptHotspots : [])
      .filter((item) => Number(item?.totalDurationMs ?? 0) >= alertThresholds.longAnimationFrameRedMs)
      .map(loafScriptKey)
      .filter(Boolean)
  );
  const events = (Array.isArray(input?.events) ? input.events : [])
    .filter((item) => item && (item.kind === "longtask" || item.kind === "long-animation-frame" || item.kind === "event-loop-gap"))
    .filter((item) => Number(item.durationMs ?? 0) >= frontendPerformanceWindowBudget(item) || hasAggregatedLoafHotspot(item, aggregatedLoafHotspotKeys))
    .sort(descDuration)
    .slice(0, 20);
  return events.map((event) => correlateFrontendPerformanceWindow(event, input)).filter(Boolean);
}

function hasAggregatedLoafHotspot(event, keys) {
  if (event?.kind !== "long-animation-frame" || !(keys instanceof Set) || keys.size === 0) return false;
  for (const script of Array.isArray(event?.scripts) ? event.scripts : []) {
    if (keys.has(loafScriptKey(script))) return true;
  }
  return false;
}

function correlateFrontendPerformanceWindow(event, input) {
  const captures = Array.isArray(input?.captures) ? input.captures : [];
  const matchingCaptures = captures.filter((capture) => samePageContext(event, capture));
  const overlapping = matchingCaptures.filter((capture) => windowsOverlap(event, capture));
  const covering = overlapping.filter((capture) => windowCovers(capture, event));
  const selectedCapture = covering[0] || overlapping[0] || nearestCapture(event, matchingCaptures) || nearestCapture(event, captures);
  const coverageStatus = selectedCapture
    ? covering.length > 0 ? "covered" : overlapping.length > 0 ? "overlapped" : "missed"
    : "no-cpu-profile";
  const profileEvidence = coverageStatus === "covered" || coverageStatus === "overlapped"
    ? sameWindowProfileEvidence(event, selectedCapture, input)
    : null;
  const sourceHint = event.kind === "long-animation-frame" ? topLoafScriptHint(event) : null;
  return {
    kind: event.kind,
    ts: event.ts ?? null,
    startAt: event.startAt ?? null,
    endAt: event.endAt ?? null,
    startEpochMs: event.startEpochMs ?? null,
    endEpochMs: event.endEpochMs ?? null,
    durationMs: event.durationMs ?? null,
    blockingDurationMs: event.blockingDurationMs ?? null,
    sampleSeq: event.sampleSeq ?? null,
    pageRole: event.pageRole ?? null,
    pageId: event.pageId ?? null,
    pageEpoch: event.pageEpoch ?? null,
    path: event.path ?? null,
    url: event.url ?? null,
    scriptCount: event.scriptCount ?? null,
    topLoafScript: sourceHint,
    cpuProfileCoverageStatus: coverageStatus,
    coverageReason: cpuProfileCoverageReason(event, selectedCapture, coverageStatus),
    capture: selectedCapture ? compactWindowCapture(selectedCapture, event) : null,
    relatedNetwork: relatedNetworkRows(event, input?.network),
    relatedSamples: relatedSampleRows(event, input?.samples),
    profileEvidence,
    valuesRedacted: true,
  };
}

function frontendPerformanceWindowBudget(event) {
  if (event?.kind === "longtask") return alertThresholds.longTaskRedMs;
  if (event?.kind === "long-animation-frame") return alertThresholds.longAnimationFrameRedMs;
  if (event?.kind === "event-loop-gap") return alertThresholds.eventLoopGapRedMs;
  return 0;
}

function performanceEventWindow(row, perf) {
  const timeOrigin = Number(perf?.timeOrigin);
  const startTime = Number(perf?.startTime);
  const duration = Number(perf?.duration);
  if (Number.isFinite(timeOrigin) && timeOrigin > 0 && Number.isFinite(startTime)) {
    const startEpochMs = timeOrigin + startTime;
    const endEpochMs = startEpochMs + (Number.isFinite(duration) ? duration : 0);
    return { startEpochMs: roundMs(startEpochMs), endEpochMs: roundMs(endEpochMs), startAt: new Date(startEpochMs).toISOString(), endAt: new Date(endEpochMs).toISOString(), source: "performance-timeOrigin-startTime" };
  }
  const observedAt = Number(perf?.observedAt);
  if (Number.isFinite(observedAt) && observedAt > 0) {
    const endEpochMs = observedAt;
    const startEpochMs = endEpochMs - (Number.isFinite(duration) ? duration : 0);
    return { startEpochMs: roundMs(startEpochMs), endEpochMs: roundMs(endEpochMs), startAt: new Date(startEpochMs).toISOString(), endAt: new Date(endEpochMs).toISOString(), source: "observedAt-minus-duration" };
  }
  const rowMs = performanceTimestampMs(row?.ts);
  if (Number.isFinite(rowMs)) {
    const endEpochMs = rowMs;
    const startEpochMs = endEpochMs - (Number.isFinite(duration) ? duration : 0);
    return { startEpochMs: roundMs(startEpochMs), endEpochMs: roundMs(endEpochMs), startAt: new Date(startEpochMs).toISOString(), endAt: new Date(endEpochMs).toISOString(), source: "row-ts-minus-duration" };
  }
  return { startEpochMs: null, endEpochMs: null, startAt: null, endAt: null, source: "missing-window" };
}

function performanceTimestampMs(value) {
  const ms = Date.parse(String(value || ""));
  return Number.isFinite(ms) ? ms : null;
}

function samePageContext(event, capture) {
  if (!capture) return false;
  if (event.pageRole && capture.pageRole && event.pageRole !== capture.pageRole) return false;
  if (event.pageId && capture.pageId && event.pageId !== capture.pageId) return false;
  return true;
}

function windowsOverlap(left, right) {
  const leftStart = Number(left?.startEpochMs);
  const leftEnd = Number(left?.endEpochMs);
  const rightStart = Number(right?.startEpochMs);
  const rightEnd = Number(right?.endEpochMs);
  if (![leftStart, leftEnd, rightStart, rightEnd].every(Number.isFinite)) return false;
  return leftStart <= rightEnd && rightStart <= leftEnd;
}

function windowCovers(outer, inner) {
  const outerStart = Number(outer?.startEpochMs);
  const outerEnd = Number(outer?.endEpochMs);
  const innerStart = Number(inner?.startEpochMs);
  const innerEnd = Number(inner?.endEpochMs);
  if (![outerStart, outerEnd, innerStart, innerEnd].every(Number.isFinite)) return false;
  return outerStart <= innerStart && outerEnd >= innerEnd;
}

function nearestCapture(event, captures) {
  const rows = Array.isArray(captures) ? captures : [];
  const eventStart = Number(event?.startEpochMs);
  const eventEnd = Number(event?.endEpochMs);
  if (![eventStart, eventEnd].every(Number.isFinite) || rows.length === 0) return null;
  return rows
    .map((capture) => ({ capture, distanceMs: captureWindowDistanceMs(eventStart, eventEnd, capture) }))
    .filter((item) => Number.isFinite(item.distanceMs))
    .sort((left, right) => left.distanceMs - right.distanceMs)[0]?.capture || null;
}

function captureWindowDistanceMs(eventStart, eventEnd, capture) {
  const start = Number(capture?.startEpochMs);
  const end = Number(capture?.endEpochMs);
  if (![start, end].every(Number.isFinite)) return Number.POSITIVE_INFINITY;
  if (eventEnd < start) return start - eventEnd;
  if (end < eventStart) return eventStart - end;
  return 0;
}

function cpuProfileCoverageReason(event, capture, status) {
  if (status === "no-cpu-profile") return "no completed performanceCapture artifact is present";
  if (!capture) return "no comparable capture window is present";
  if (status === "covered") return "performanceCapture window fully covers this frontend performance event";
  if (status === "overlapped") return "performanceCapture window overlaps this frontend performance event, but does not fully cover it";
  const eventStart = Number(event?.startEpochMs);
  const eventEnd = Number(event?.endEpochMs);
  const captureStart = Number(capture?.startEpochMs);
  const captureEnd = Number(capture?.endEpochMs);
  if (Number.isFinite(captureStart) && Number.isFinite(eventEnd) && captureStart > eventEnd) return "nearest performanceCapture started after this frontend performance window ended";
  if (Number.isFinite(captureEnd) && Number.isFinite(eventStart) && captureEnd < eventStart) return "nearest performanceCapture ended before this frontend performance window started";
  return "completed performanceCapture exists but its window could not be matched to this frontend event";
}

function compactWindowCapture(capture, event) {
  const distanceMs = captureWindowDistanceMs(Number(event?.startEpochMs), Number(event?.endEpochMs), capture);
  return {
    captureId: capture.captureId ?? null,
    commandId: capture.commandId ?? null,
    pageRole: capture.pageRole ?? null,
    pageId: capture.pageId ?? null,
    startAt: capture.startAt ?? null,
    endAt: capture.endAt ?? null,
    durationMs: capture.durationMs ?? null,
    windowDistanceMs: Number.isFinite(distanceMs) ? roundMs(distanceMs) : null,
    profileSampleCount: capture.profileSampleCount ?? null,
    profileTotalTimeMs: capture.profileTotalTimeMs ?? null,
    profileTimelineStatus: capture.profileTimelineStatus ?? null,
    profileTimelineSampleCount: capture.profileTimelineSampleCount ?? null,
    profileTimelineTotalTimeMs: capture.profileTimelineTotalTimeMs ?? null,
    profileTimelineStartAt: capture.profileTimelineStartAt ?? null,
    profileTimelineEndAt: capture.profileTimelineEndAt ?? null,
    valuesRedacted: true,
  };
}

function relatedNetworkRows(event, network) {
  const rows = Array.isArray(network) ? network : [];
  const start = Number(event?.startEpochMs);
  const end = Number(event?.endEpochMs);
  const toleranceMs = Math.max(1000, Math.min(10000, Number(event?.durationMs || 0) + 1000));
  if (![start, end].every(Number.isFinite)) return [];
  return rows
    .filter((item) => {
      const ms = performanceTimestampMs(item?.ts);
      if (!Number.isFinite(ms)) return false;
      return ms >= start - toleranceMs && ms <= end + toleranceMs;
    })
    .sort((left, right) => Math.abs(Number(performanceTimestampMs(left?.ts)) - start) - Math.abs(Number(performanceTimestampMs(right?.ts)) - start))
    .slice(0, 8)
    .map(compactRelatedNetworkRow);
}

function compactRelatedNetworkRow(item) {
  const url = item?.url ?? item?.request?.url ?? item?.response?.url ?? item?.detail?.url ?? "";
  return {
    ts: item?.ts ?? null,
    sampleSeq: item?.sampleSeq ?? null,
    phase: item?.phase ?? item?.type ?? null,
    method: item?.method ?? item?.request?.method ?? null,
    status: item?.status ?? item?.response?.status ?? null,
    urlPath: urlPathOnly(url),
    bodyByteCount: numberOrNull(item?.bodyByteCount ?? item?.response?.bodyByteCount ?? item?.bodySummary?.byteCount ?? item?.bodySummary?.bodyByteCount),
    durationMs: numberOrNull(item?.durationMs ?? item?.response?.durationMs),
    routeSessionId: item?.routeSessionId ?? item?.sessionId ?? null,
    traceId: item?.traceId ?? item?.bodySummary?.traceId ?? null,
    valuesRedacted: true,
  };
}

function relatedSampleRows(event, samples) {
  const rows = Array.isArray(samples) ? samples : [];
  const start = Number(event?.startEpochMs);
  const end = Number(event?.endEpochMs);
  const toleranceMs = Math.max(1000, Math.min(10000, Number(event?.durationMs || 0) + 1000));
  if (![start, end].every(Number.isFinite)) return [];
  return rows
    .filter((item) => {
      const ms = performanceTimestampMs(item?.ts);
      if (!Number.isFinite(ms)) return false;
      return ms >= start - toleranceMs && ms <= end + toleranceMs;
    })
    .slice(-6)
    .map((sample) => ({
      ts: sample?.ts ?? null,
      sampleSeq: sample?.seq ?? sample?.sampleSeq ?? null,
      pageRole: sample?.pageRole ?? null,
      path: limitText(sample?.path ?? "", 160),
      routeSessionId: sample?.routeSessionId ?? null,
      activeSessionId: sample?.activeSessionId ?? null,
      traceIds: sampleTraceIdsForPerformance(sample).slice(0, 6),
      valuesRedacted: true,
    }));
}

function sampleTraceIdsForPerformance(sample) {
  const ids = new Set();
  for (const group of [sample?.messages, sample?.traceRows, sample?.turns, sample?.diagnostics]) {
    if (!Array.isArray(group)) continue;
    for (const item of group) if (item?.traceId) ids.add(String(item.traceId));
  }
  if (sample?.traceId) ids.add(String(sample.traceId));
  return Array.from(ids);
}

function topLoafScriptHint(event) {
  const scripts = Array.isArray(event?.scripts) ? event.scripts : [];
  return scripts
    .slice()
    .sort((left, right) => Number(right.durationMs ?? 0) - Number(left.durationMs ?? 0))[0] || null;
}

async function buildFrontendPerformanceSourceMapState(artifacts) {
  const candidates = sourceMapArtifactCandidates(artifacts);
  const maps = [];
  let failedCount = 0;
  for (const candidate of candidates) {
    const parsed = await readJson(candidate.path);
    const map = parseFrontendSourceMap(parsed, candidate);
    if (map) maps.push(map);
    else failedCount += 1;
  }
  return { artifactCount: candidates.length, loadedCount: maps.length, failedCount, maps, valuesRedacted: true };
}

function sourceMapArtifactCandidates(artifacts) {
  const rows = [];
  const seen = new Set();
  for (const item of Array.isArray(artifacts) ? artifacts : []) {
    if (!item || typeof item !== "object") continue;
    const paths = [item.path, item.sourceMapPath, item.mapPath, item.summaryPath].filter((value) => typeof value === "string" && value);
    for (const candidatePath of paths) {
      const kind = String(item.kind || item.type || "").toLowerCase();
      const url = String(item.url || item.sourceURL || item.sourceMapUrl || "");
      const pathText = String(candidatePath);
      const looksLikeMap = kind.includes("source-map") || kind.includes("sourcemap") || pathText.endsWith(".map") || url.endsWith(".map");
      if (!looksLikeMap || seen.has(pathText)) continue;
      seen.add(pathText);
      rows.push({ path: pathText, url: url || null, kind: item.kind ?? null, ts: item.ts ?? null, valuesRedacted: true });
    }
  }
  return rows.slice(-40);
}

function parseFrontendSourceMap(raw, candidate) {
  if (!raw || typeof raw !== "object" || typeof raw.mappings !== "string" || !Array.isArray(raw.sources)) return null;
  const parsedMappings = parseSourceMapMappings(raw.mappings, raw.sources, Array.isArray(raw.names) ? raw.names : []);
  return {
    path: candidate.path,
    url: candidate.url ?? null,
    file: typeof raw.file === "string" ? raw.file : null,
    sources: raw.sources,
    names: Array.isArray(raw.names) ? raw.names : [],
    lines: parsedMappings.lines,
    mappingCount: parsedMappings.mappingCount,
    valuesRedacted: true,
  };
}

function parseSourceMapMappings(mappings, sources, names) {
  const lines = [];
  let sourceIndex = 0;
  let originalLine = 0;
  let originalColumn = 0;
  let nameIndex = 0;
  const rawLines = String(mappings || "").split(";");
  for (let generatedLine = 0; generatedLine < rawLines.length; generatedLine += 1) {
    let generatedColumn = 0;
    const segments = [];
    for (const segmentText of rawLines[generatedLine].split(",")) {
      if (!segmentText) continue;
      const values = decodeSourceMapVlqSegment(segmentText);
      if (values.length === 0) continue;
      generatedColumn += Number(values[0] || 0);
      if (values.length >= 4) {
        sourceIndex += Number(values[1] || 0);
        originalLine += Number(values[2] || 0);
        originalColumn += Number(values[3] || 0);
        if (values.length >= 5) nameIndex += Number(values[4] || 0);
        if (sources[sourceIndex]) {
          segments.push({
            generatedColumn,
            source: String(sources[sourceIndex]),
            originalLine,
            originalColumn,
            name: names[nameIndex] ? String(names[nameIndex]) : null,
            valuesRedacted: true,
          });
        }
      }
    }
    lines[generatedLine] = segments;
  }
  return { lines, mappingCount: lines.reduce((sum, line) => sum + (Array.isArray(line) ? line.length : 0), 0), valuesRedacted: true };
}

function decodeSourceMapVlqSegment(segmentText) {
  const chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  const values = [];
  let value = 0;
  let shift = 0;
  for (const char of String(segmentText || "")) {
    const digit = chars.indexOf(char);
    if (digit < 0) return [];
    const continuation = (digit & 32) !== 0;
    value += (digit & 31) << shift;
    if (continuation) {
      shift += 5;
      continue;
    }
    const negative = (value & 1) === 1;
    const decoded = value >> 1;
    values.push(negative ? -decoded : decoded);
    value = 0;
    shift = 0;
  }
  return values;
}

function createFrontendPerformanceSourceMapper(maps) {
  const loadedMaps = Array.isArray(maps) ? maps.filter((item) => item && Array.isArray(item.lines)) : [];
  return {
    loadedCount: loadedMaps.length,
    resolve(url, lineNumber, columnNumber, sourceCharPosition) {
      if (loadedMaps.length === 0) return null;
      const matching = loadedMaps.filter((map) => sourceMapMatchesUrl(map, url));
      if (matching.length === 0) return { status: "missing", mapped: null };
      const generatedLine = sourceMapGeneratedLine(lineNumber);
      const generatedColumn = sourceMapGeneratedColumn(columnNumber, sourceCharPosition);
      if (![generatedLine, generatedColumn].every(Number.isFinite)) return { status: "unmapped", mapped: null };
      for (const map of matching) {
        const mapped = lookupSourceMapPosition(map, generatedLine, generatedColumn);
        if (mapped) return { status: "mapped", mapped, map };
      }
      return { status: "unmapped", mapped: null };
    },
  };
}

function sourceMapMatchesUrl(map, url) {
  const raw = String(url || "");
  if (!raw) return false;
  const urlBase = sourceFileFromUrl(raw);
  const mapFile = sourceFileFromUrl(map?.file || "");
  const mapPathBase = sourceFileFromUrl(map?.path || "");
  const mapUrlBase = sourceFileFromUrl(map?.url || "");
  const expectedMapBase = urlBase ? urlBase + ".map" : "";
  return Boolean(
    (mapFile && urlBase && mapFile === urlBase) ||
    (mapPathBase && expectedMapBase && mapPathBase === expectedMapBase) ||
    (mapUrlBase && expectedMapBase && mapUrlBase === expectedMapBase) ||
    (mapPathBase && urlBase && mapPathBase.replace(/\.map$/u, "") === urlBase) ||
    (mapUrlBase && urlBase && mapUrlBase.replace(/\.map$/u, "") === urlBase)
  );
}

function sourceMapGeneratedLine(lineNumber) {
  const line = Number(lineNumber);
  return Number.isFinite(line) && line >= 0 ? Math.floor(line) : 0;
}

function sourceMapGeneratedColumn(columnNumber, sourceCharPosition) {
  if (sourceCharPosition !== null && sourceCharPosition !== undefined) {
    const charPosition = Number(sourceCharPosition);
    if (Number.isFinite(charPosition) && charPosition >= 0) return Math.floor(charPosition);
  }
  const column = Number(columnNumber);
  return Number.isFinite(column) && column >= 0 ? Math.floor(column) : null;
}

function lookupSourceMapPosition(map, generatedLine, generatedColumn) {
  const line = Array.isArray(map?.lines?.[generatedLine]) ? map.lines[generatedLine] : [];
  let selected = null;
  for (const segment of line) {
    if (Number(segment?.generatedColumn) <= generatedColumn) selected = segment;
    else break;
  }
  if (!selected) return null;
  return {
    sourceFile: limitText(selected.source || "", 180),
    sourceLine: Number.isFinite(Number(selected.originalLine)) ? Number(selected.originalLine) + 1 : null,
    sourceColumn: numberOrNull(selected.originalColumn),
    sourceName: selected.name ? limitText(selected.name, 160) : null,
    generatedLine,
    generatedColumn,
    valuesRedacted: true,
  };
}

function buildFrontendSourceAttribution(input) {
  const sourceFiles = new Map();
  const add = (row) => {
    const file = row?.sourceFile || sourceFileFromUrl(row?.sourceURL || row?.url);
    if (!file) return;
    const existing = sourceFiles.get(file) || { sourceFile: file, count: 0, sourceMapStatus: row?.sourceMapStatus || "missing", valuesRedacted: true };
    existing.count += 1;
    if (existing.sourceMapStatus !== "mapped") existing.sourceMapStatus = row?.sourceMapStatus || existing.sourceMapStatus;
    sourceFiles.set(file, existing);
  };
  for (const row of Array.isArray(input?.scriptHotspots) ? input.scriptHotspots : []) add(row);
  for (const row of Array.isArray(input?.profileHotspots) ? input.profileHotspots : []) add(row);
  for (const stack of Array.isArray(input?.profileStacks) ? input.profileStacks : []) {
    for (const frame of Array.isArray(stack?.frames) ? stack.frames : []) add(frame);
  }
  const rows = Array.from(sourceFiles.values());
  const mappedCount = rows.filter((item) => item.sourceMapStatus === "mapped").length;
  const unmappedCount = rows.filter((item) => item.sourceMapStatus === "unmapped").length;
  const state = input?.sourceMapState && typeof input.sourceMapState === "object" ? input.sourceMapState : {};
  const loadedCount = Number(state.loadedCount ?? 0);
  const status = mappedCount > 0 ? "mapped" : loadedCount > 0 || unmappedCount > 0 ? "unmapped" : "missing";
  const note = status === "mapped"
    ? "Source-map artifact was loaded; mapped rows include original source file and line while raw browser locations remain present."
    : loadedCount > 0
      ? "Source-map artifact was loaded, but observed browser locations did not resolve to original source positions."
      : "No source-map artifact is loaded by this analyzer; function/file/line fields are raw browser URLs or CPU profile callFrame locations.";
  return {
    sourceMapStatus: status,
    note,
    sourceMapArtifactCount: numberOrNull(state.artifactCount),
    sourceMapLoadedCount: numberOrNull(state.loadedCount),
    sourceMapFailedCount: numberOrNull(state.failedCount),
    sourceFiles: rows.sort((left, right) => Number(right.count ?? 0) - Number(left.count ?? 0)).slice(0, 20),
    valuesRedacted: true,
  };
}

function annotateProfileFrameSource(frame) {
  if (!frame || typeof frame !== "object") return frame ?? null;
  const source = sourceAttributionFor(frame.url, frame.functionName, frame.lineNumber, frame.columnNumber, null);
  return { ...frame, sourceFile: source.sourceFile, sourceLine: source.sourceLine, sourceColumn: source.sourceColumn, sourceMapStatus: source.sourceMapStatus, sourceAttributionMode: source.sourceAttributionMode, valuesRedacted: true };
}

function sourceAttributionFor(url, functionName, lineNumber, columnNumber, sourceCharPosition) {
  const resolved = frontendPerformanceSourceMapper?.resolve ? frontendPerformanceSourceMapper.resolve(url, lineNumber, columnNumber, sourceCharPosition) : null;
  if (resolved?.status === "mapped" && resolved.mapped) {
    return {
      functionName: limitText(resolved.mapped.sourceName || functionName || "", 160),
      sourceFile: resolved.mapped.sourceFile,
      sourceLine: resolved.mapped.sourceLine,
      sourceColumn: resolved.mapped.sourceColumn,
      sourceCharPosition: numberOrNull(sourceCharPosition),
      sourceMapStatus: "mapped",
      sourceAttributionMode: "source-map-original-position",
      rawSourceFile: sourceFileFromUrl(url),
      rawLineNumber: numberOrNull(lineNumber),
      rawColumnNumber: numberOrNull(columnNumber),
      valuesRedacted: true,
    };
  }
  return {
    functionName: limitText(functionName ?? "", 160),
    sourceFile: sourceFileFromUrl(url),
    sourceLine: numberOrNull(lineNumber),
    sourceColumn: numberOrNull(columnNumber),
    sourceCharPosition: numberOrNull(sourceCharPosition),
    sourceMapStatus: resolved?.status === "unmapped" ? "unmapped" : "missing",
    sourceAttributionMode: resolved?.status === "unmapped" ? "source-map-loaded-no-match" : "browser-raw-url-line-column",
    valuesRedacted: true,
  };
}

function sourceFileFromUrl(value) {
  const text = String(value || "");
  if (!text) return null;
  try {
    const parsed = new URL(text, "http://local.invalid");
    const path = parsed.pathname || "";
    const parts = path.split("/").filter(Boolean);
    return limitText(parts[parts.length - 1] || path || text, 160);
  } catch {
    const clean = text.split(/[?#]/u)[0];
    const parts = clean.split("/").filter(Boolean);
    return limitText(parts[parts.length - 1] || clean, 160);
  }
}

function urlPathOnly(value) {
  const text = String(value || "");
  if (!text) return null;
  try {
    const parsed = new URL(text, "http://local.invalid");
    return limitText(parsed.pathname || "/", 180);
  } catch {
    return limitText(text.split("?")[0] || text, 180);
  }
}

function frontendPerformanceMaxNumber(items, getter) {
  const selected = maxByNumber(items, getter);
  return selected ? numberOrNull(getter(selected)) : null;
}

function descDuration(left, right) {
  return Number(right.durationMs ?? 0) - Number(left.durationMs ?? 0) || String(right.ts || "").localeCompare(String(left.ts || ""));
}

function roundMs(value) {
  return Number((Number(value || 0)).toFixed(2));
}
`;
}