const TRACEPARENT_VERSION = "00";

const DEFAULT_TRACE_FLAGS = "01";

const MAX_TRACEPARENT_LENGTH = 128;

const TRACE_ID_RE = /^[0-9a-f]{32}$/;

const SPAN_ID_RE = /^[0-9a-f]{16}$/;

const TRACE_FLAGS_RE = /^[0-9a-f]{2}$/;

const TRACEPARENT_VERSION_RE = /^[0-9a-f]{2}$/;

export type DiagnosticTraceContext = {

/** W3C trace id, 32 lowercase hex chars. */

return !/^0+$/.test(value);

}

function randomTraceId(): string {

let traceId = randomHex(16);

while (!isNonZeroHex(traceId)) {

traceId = randomHex(16);

}

return traceId;

}

function randomSpanId(): string {

let spanId = randomHex(8);

while (!isNonZeroHex(spanId)) {

spanId = randomHex(8);

}

return spanId;

}

export function isValidDiagnosticTraceId(value: unknown): value is string {

return typeof value === "string" && TRACE_ID_RE.test(value) && isNonZeroHex(value);

}

export function parseDiagnosticTraceparent(

traceparent: string | undefined,

): DiagnosticTraceContext | undefined {

const parts = traceparent?.trim().toLowerCase().split("-");

if (!parts || parts.length !== 4) {

if (typeof traceparent !== "string" || traceparent.length > MAX_TRACEPARENT_LENGTH) {

return undefined;

}

const parts = traceparent.trim().toLowerCase().split("-");

if (!parts || parts.length < 4) {

return undefined;

}

const [version, traceId, spanId, traceFlags] = parts;

if (version !== TRACEPARENT_VERSION) {

if (

!TRACEPARENT_VERSION_RE.test(version) ||

version === "ff" ||

(version === TRACEPARENT_VERSION && parts.length !== 4)

) {

return undefined;

}

const normalizedTraceId = normalizeTraceId(traceId);

input: DiagnosticTraceContextInput = {},

): DiagnosticTraceContext {

const parsed = parseDiagnosticTraceparent(input.traceparent);

const traceId = normalizeTraceId(input.traceId) ?? parsed?.traceId ?? randomHex(16);

const spanId = normalizeSpanId(input.spanId) ?? parsed?.spanId ?? randomHex(8);

const traceId = normalizeTraceId(input.traceId) ?? parsed?.traceId ?? randomTraceId();

const spanId = normalizeSpanId(input.spanId) ?? parsed?.spanId ?? randomSpanId();

const parentSpanId = normalizeSpanId(input.parentSpanId);

return {

traceId,