const readline = require("node:readline");

function send(message) {
  process.stdout.write(`${JSON.stringify(message)}\n`);
}

const rl = readline.createInterface({
  input: process.stdin,
  crlfDelay: Infinity,
});
const heldInspections = [];
let inspectionCount = 0;
let activeInspections = 0;

rl.on("line", (line) => {
  if (!line.trim()) return;
  const message = JSON.parse(line);
  const method = message && typeof message.method === "string" ? message.method : null;

  if (method === "initialize") {
    send({
      jsonrpc: "2.0",
      id: message.id,
      result: {
        ok: true,
        supportedMethods: ["environmentExecute", "configChanged", "environmentInspectLease", "health"],
      },
    });
    return;
  }

  if (method === "environmentExecute") {
    const delayMs = Number(message.params?.delayMs ?? 0);
    setTimeout(() => {
      send({
        jsonrpc: "2.0",
        id: message.id,
        result: {
          exitCode: 0,
          signal: null,
          timedOut: false,
          stdout: "ok\n",
          stderr: "",
        },
      });
    }, delayMs);
    return;
  }

  if (method === "configChanged") {
    if (message.params.config.releaseInspections) {
      for (const complete of heldInspections.splice(0)) complete();
    }
    setTimeout(() => send({
      jsonrpc: "2.0", id: message.id,
      ...(message.params.config.fail
        ? { error: { code: -32000, message: "configuration rejected" } }
        : { result: {} }),
    }), Number(message.params.config.delayMs ?? 0));
    return;
  }

  if (method === "environmentInspectLease") {
    inspectionCount++;
    activeInspections++;
    const complete = () => { activeInspections--; send({ jsonrpc: "2.0", id: message.id,
      result: { providerLeaseId: message.params.providerLeaseId, state: "destroyed" } }); };
    if (message.params.leaseMetadata?.holdInspection) heldInspections.push(complete);
    else complete();
    return;
  }
  if (method === "health") {
    send({ jsonrpc: "2.0", id: message.id, result: { status: "ok", details: { inspectionCount, activeInspections } } });
    return;
  }

  if (method === "shutdown") {
    send({
      jsonrpc: "2.0",
      id: message.id,
      result: {},
    });
    setImmediate(() => process.exit(0));
    return;
  }

  send({
    jsonrpc: "2.0",
    id: message.id,
    error: {
      code: -32601,
      message: `Unhandled method: ${method}`,
    },
  });
});