executor.js

const { getContainer, docker, languages, releaseContainer } = require("./containerManager");

async function executeCodeInContainer(language, code, input) {
  const container = await getContainer(language);
  const { extension, interpreted, compileCmd, runCmd, command } = languages[language];

  try {
    const filePath = `/code/Main.${extension}`;
    const safeCode = code.replace(/'/g, "'\\''");
    const writeCodeCmd = `echo '${safeCode}' > ${filePath}`;

    let finalCommand = interpreted ? command : `${compileCmd} && ${runCmd}`;

    const exec = await container.exec({
      AttachStdout: true,
      AttachStderr: true,
      AttachStdin: !!input,
      Tty: false,
      Cmd: ["/bin/sh", "-c", `${writeCodeCmd} && ${finalCommand}`],
    });

    return new Promise((resolve, reject) => {
      exec.start({ hijack: true, stdin: !!input }, (err, stream) => {
        if (err) return reject({ success: false, error: `Execution failed: ${err.message}` });

        let outputBuffers = [];
        let errorBuffers = [];

        docker.modem.demuxStream(
          stream,
          { write: (chunk) => outputBuffers.push(chunk) },
          { write: (chunk) => errorBuffers.push(chunk) }
        );

        const startTime = Date.now();

        stream.on("error", (error) => {
          reject({ success: false, error: `Stream error: ${error.message}` });
        });

        if (input) {
          stream.write(input + "\n");
        }

        stream.on("end", () => {
          const executionTime = Date.now() - startTime;
          const output = Buffer.concat(outputBuffers).toString().trim();
          const error = Buffer.concat(errorBuffers).toString().trim();

          resolve({
            success: error.length === 0,
            output,
            error,
            executionTime,
          });
        });

        stream.on("close", () => {
          if (outputBuffers.length === 0 && errorBuffers.length === 0) {
            reject({ success: false, error: "No output received, possible execution failure." });
          }
        });
      });
    });
  } catch (error) {
    return { success: false, error: `Execution failed: ${error.message}` };
  } finally {
    releaseContainer(language, container.id);
  }
}

module.exports = {
  executeCodeInContainer,
};