import * as Cause from "effect/Cause";

const MAX_ERROR_TRACE_NODES = 128;

export function findErrorTraceId(error: unknown): string | null {
  const seen = new Set<object>();
  const pending: Array<unknown> = [error];
  let inspectedNodeCount = 0;

  while (pending.length > 0 && inspectedNodeCount < MAX_ERROR_TRACE_NODES) {
    const current = pending.pop();
    inspectedNodeCount += 1;
    if (typeof current !== "object" || current === null || seen.has(current)) {
      continue;
    }
    seen.add(current);
    const record = current as {
      readonly cause?: unknown;
      readonly errors?: unknown;
      readonly traceId?: unknown;
    };
    if (typeof record.traceId === "string" && record.traceId.trim().length > 0) {
      return record.traceId;
    }

    if (Array.isArray(record.errors)) {
      for (let index = record.errors.length - 1; index >= 0; index -= 1) {
        pending.push(record.errors[index]);
      }
    }
    if (Cause.isCause(current)) {
      for (let index = current.reasons.length - 1; index >= 0; index -= 1) {
        const reason = current.reasons[index];
        switch (reason?._tag) {
          case "Fail":
            pending.push(reason.error);
            break;
          case "Die":
            pending.push(reason.defect);
            break;
        }
      }
    }
    if ("cause" in record) {
      pending.push(record.cause);
    }
  }

  return null;
}