bridge.mjs

import { spawn } from "node:child_process";
import { execFileSync } from "node:child_process";
import process from "node:process";
import { fileURLToPath } from "node:url";
import { radialToAxes, shouldResetStaleInput } from "./joystick.mjs";
import { WorkLouderRPC } from "./worklouder-rpc.mjs";

const debug = process.argv.includes("--debug");
const staleInputTimeoutMs = 350;

try {
  execFileSync("pgrep", ["-x", "input"], { stdio: "ignore" });
  throw new Error(
    "Work Louder Input is running. Quit Input before starting the scroll bridge " +
      "or it will restore the RADIAL mapping.",
  );
} catch (error) {
  if (error?.status === undefined) throw error;
}

const rpc = new WorkLouderRPC();
let emitter;
let shuttingDown = false;
let lastInputTime = Date.now();
let axesActive = false;

function writeAxes(x, y) {
  if (emitter?.stdin.writable) emitter.stdin.write(`${x} ${y}\n`);
}

function resetAxes(reason) {
  axesActive = false;
  writeAxes(0, 0);
  if (debug && reason) console.log(`axis x=0.000 y=0.000 ${reason}`);
}

rpc.on("disconnect", (error) => {
  resetAxes("device disconnected");
  console.error(`Creator Micro 2 disconnected: ${error.message}`);
  if (!shuttingDown) emitter?.kill("SIGTERM");
});
await rpc.open();

const extraArguments = process.argv.slice(2).filter((argument) => argument !== "--debug");
emitter = spawn(
  fileURLToPath(new URL(".build/release/codex-micro-scroll", import.meta.url)),
  ["--stream", ...extraArguments],
  { stdio: ["pipe", "inherit", "inherit"] },
);

emitter.on("error", async (error) => {
  console.error(`Could not start the scroll emitter: ${error.message}`);
  await rpc.close().catch(() => {});
  process.exit(1);
});

emitter.on("exit", async (code, signal) => {
  await rpc.close().catch(() => {});
  if (signal && !shuttingDown) {
    console.error(`Scroll emitter stopped by ${signal}`);
  } else if (code !== null && code !== 0) {
    console.error(`Scroll emitter exited with code ${code}`);
  }
  process.exit(shuttingDown ? 0 : code ?? 1);
});

let lastX = 0;
let lastY = 0;
let lastDebugTime = 0;

rpc.onNotification("kb.radial", (params) => {
  const operation = params?.o;
  lastInputTime = Date.now();
  if (operation === 0) {
    resetAxes("released");
    return;
  }

  const angle = params?.a;
  const distance = params?.d;
  if (!Number.isFinite(angle) || !Number.isFinite(distance)) return;

  ({ x: lastX, y: lastY } = radialToAxes(angle, distance));
  axesActive = lastX !== 0 || lastY !== 0;
  writeAxes(lastX, lastY);

  const now = Date.now();
  if (debug && now - lastDebugTime >= 100) {
    console.log(
      `axis x=${lastX.toFixed(3)} y=${lastY.toFixed(3)} ` +
        `angle=${angle.toFixed(3)} distance=${distance.toFixed(3)} op=${operation}`,
    );
    lastDebugTime = now;
  }
});

const watchdog = setInterval(() => {
  if (
    shouldResetStaleInput({
      active: axesActive,
      lastInputTime,
      now: Date.now(),
      timeoutMs: staleInputTimeoutMs,
    })
  ) {
    resetAxes("input timeout");
  }
}, 50);

for (const signal of ["SIGINT", "SIGTERM"]) {
  process.on(signal, async () => {
    if (shuttingDown) return;
    shuttingDown = true;
    clearInterval(watchdog);
    resetAxes();
    await rpc.close().catch(() => {});
    emitter.kill(signal);
  });
}

console.log(
  "Creator Micro 2 radial stream connected over USB/Bluetooth. Press Control-C to stop.",
);