// handles mounting/unmounting the USB drive
import { execSync } from 'node:child_process';
import { mkdirSync, rmdirSync, readFileSync, realpathSync, existsSync } from 'node:fs';

export function isMounted(mountPath) {
  try {
    return readFileSync('/proc/mounts', 'utf8').includes(` ${mountPath} `);
  } catch {
    return false;
  }
}

export function mountDrive(devNode, mountPath) {
  if (isMounted(mountPath)) {
    console.log(`[MOUNT] ${mountPath} is already mounted.`);
    return true;
  }
  
  try {
    // ensure the directory exists first
    mkdirSync(mountPath, { recursive: true });
    
    // mount with open permissions so copyparty/rsync don't hit EACCES
    execSync(`mount -o umask=000,uid=1000,gid=1000 ${devNode} ${mountPath}`);
    console.log(`[MOUNT] success: ${devNode} -> ${mountPath}`);
    return true;
  } catch (err) {
    console.error(`[MOUNT] failed:`, err.message);
    return false;
  }
}

export function unmountDrive(mountPath) {
  if (!isMounted(mountPath)) {
    // cleanup orphaned directory just in case
    try { rmdirSync(mountPath); } catch {}
    return;
  }

  try {
    console.log(`[UNMOUNT] flushing buffers and unmounting ${mountPath}...`);
    execSync('sync'); // force kernel to write any pending data to the usb
    execSync(`umount -l ${mountPath}`); // lazy unmount in case a process is stuck reading
    rmdirSync(mountPath);
    console.log(`[UNMOUNT] cleanly unmounted and removed directory.`);
  } catch (err) {
    console.error(`[UNMOUNT] failed:`, err.message);
  }
}

export function driveExists(targetuid) {
    const linuidpath = '/dev/disk/by-uid/${targetuid}'
    if (!existsSync(linuidpath)) {
        return null;
    }
    try {
        return realpathSync(linuidpath)
    } catch {
        return null;
    }
}