TypeScript contracts

import http from "node:http";
import {
  CapabilitiesDigest, RequestSchema, ReasonControlAlreadyOwned,
  type Description, type Grant, type Response,
} from "./rt_control_api_generated.ts";

const socketPath = "/run/rosie-rt-core/control.sock";

function call(method: string, path: string, body?: object): Promise<Response> {
  return new Promise((resolve, reject) => {
    const req = http.request({ socketPath, method, path, headers: { "Content-Type": "application/json" } }, (res) => {
      let text = "";
      res.setEncoding("utf8");
      res.on("data", (chunk) => (text += chunk));
      res.on("end", () => resolve(JSON.parse(text) as Response));
    });
    req.on("error", reject);
    if (body) req.write(JSON.stringify(body));
    req.end();
  });
}

const d = (await call("GET", "/v1/describe")).data as Description;
if (d.capabilities_digest !== CapabilitiesDigest) throw new Error("contract mismatch");
console.log(d.backend, d.axes.map((a) => `${a.id} [${a.min_position}, ${a.max_position}] ${a.position_unit}`));

const r = await call("POST", "/v1/control", {
  schema: RequestSchema, operation: "acquire", controller: "ts-demo",
  binding: { pair_id: "cell-a", revision: 1, configuration_sha256: d.configuration_sha256, machine_sha256: d.machine_sha256 },
});
if (r.error === ReasonControlAlreadyOwned) console.log("someone else has control");
else if (!r.error) console.log("generation", (r.data as Grant).generation);

import {
  decodeTelemetryBatchHeaderV1, decodeCycleCaptureRecordV2,
  TelemetryBatchHeaderV1Bytes, CycleCaptureRecordV2Bytes,
} from "./rt_protocol_generated.ts";

// Feed raw chunks from GET /v1/telemetry/stream?after=<cursor>. HTTP chunks need
// not line up with batches, so buffer until a whole batch is available.
let pending = new Uint8Array(0);
let cursor = 0n;

export function onChunk(chunk: Uint8Array) {
  const joined = new Uint8Array(pending.length + chunk.length);
  joined.set(pending);
  joined.set(chunk, pending.length);
  pending = joined;
  for (;;) {
    if (pending.length < TelemetryBatchHeaderV1Bytes) return;
    const h = decodeTelemetryBatchHeaderV1(pending.subarray(0, TelemetryBatchHeaderV1Bytes));
    if (h.Magic !== 0x31425452 || h.Version !== 1 || h.RecordBytes !== CycleCaptureRecordV2Bytes) throw new Error("bad header");
    const size = TelemetryBatchHeaderV1Bytes + h.RecordCount * CycleCaptureRecordV2Bytes;
    if (pending.length < size) return;
    if (h.Dropped !== 0n) console.warn(`lost ${h.Dropped} records`);
    for (let i = 0; i < h.RecordCount; i++) {
      const at = TelemetryBatchHeaderV1Bytes + i * CycleCaptureRecordV2Bytes;
      const rec = decodeCycleCaptureRecordV2(pending.subarray(at, at + CycleCaptureRecordV2Bytes));
      console.log(rec.Seq, rec.Ax[0].Position); // Position is in drive counts
    }
    cursor = h.LastSequence; // resume point
    pending = pending.slice(size);
  }
}