const http = require("http");

function dockerRequest(path, method, body = null) {
  return new Promise((resolve, reject) => {
    const options = {
      socketPath: "/var/run/docker.sock",
      path: path,
      method: method,
      headers: {
        "Content-Type": "application/json",
      },
    };

    const req = http.request(options, (res) => {
      let data = "";
      res.on("data", (chunk) => (data += chunk));
      res.on("end", () => {
        if (res.statusCode >= 200 && res.statusCode < 300) {
          try {
            resolve(data ? JSON.parse(data) : null);
          } catch (e) {
            resolve(data);
          }
        } else {
          reject(new Error(`Docker API Error ${res.statusCode}: ${data}`));
        }
      });
    });

    req.on("error", (err) => reject(err));
    if (body) {
      req.write(JSON.stringify(body));
    }
    req.end();
  });
}

async function runExec(containerName, cmd) {
  try {
    // 1. Create exec instance
    const execConfig = {
      AttachStdout: true,
      AttachStderr: true,
      Cmd: cmd,
    };
    const createRes = await dockerRequest(`/containers/${containerName}/exec`, "POST", execConfig);
    const execId = createRes.Id;
    
    // 2. Start exec instance
    // Note: Start API returns raw stream, so we use http.request directly to read it
    return new Promise((resolve, reject) => {
      const options = {
        socketPath: "/var/run/docker.sock",
        path: `/exec/${execId}/start`,
        method: "POST",
        headers: {
          "Content-Type": "application/json",
        },
      };

      const req = http.request(options, (res) => {
        let output = "";
        res.on("data", (chunk) => (output += chunk));
        res.on("end", () => {
          // Docker multiplexes stdout/stderr in the stream.
          // First 8 bytes of each frame contain header info: [stream_type, 0, 0, 0, size1, size2, size3, size4]
          // For simple outputs, we can clean up non-printable characters or parse directly
          resolve(output);
        });
      });

      req.on("error", (err) => reject(err));
      req.write(JSON.stringify({ Detach: false, Tty: false }));
      req.end();
    });
  } catch (err) {
    throw err;
  }
}

async function main() {
  const result = await runExec("paddleocr-vllm-server", ["nvidia-smi", "--query-gpu=index,name,utilization.gpu,utilization.memory,memory.total,memory.used,memory.free,uuid", "--format=csv,noheader,nounits"]);
  console.log("Exec output:");
  console.log(result);
}

main().catch(console.error);