static int fileOpBot_maxReadSize = 500000;
static int fileOpBot_maxWriteSize = 500000;

static S fileOpBot(S s) ctex {
  new Matches m;
  
  if "get user home"
    ret ok(userHome());
  
  if "list directory *"
    ret structure(listDirAwarenessStyle(new File(assertAbsolutePath(m.unq(0)))));
    
  if "mkdir *" {
    S dir = assertAbsolutePath(m.unq(0));
    mkdir(new File(dir));
    ret new File(dir).exists() ? "ok" : "problem";
  }
  
  if (matchOneOf(s, m, "rmdir *", "delete file *")) {
    S dir = assertAbsolutePath(m.unq(0));
    new File(dir).delete();
    ret !new File(dir).exists() ? "ok" : "problem";
  }
  
  if "load file * bin from * l *" {
    File f = new File(assertAbsolutePath(m.unq(0)));
    long from = parseLong(m.unq(1));
    int l = parseInt(m.unq(2));
    if (l > fileOpBot_maxReadSize)
      fail(format("Can't read more than * bytes per call", fileOpBot_maxReadSize));
    byte[] buf = new byte[l];
    RandomAccessFile raf = new RandomAccessFile(f, "r");
    try {
      raf.seek(from);
      raf.readFully(buf);
      ret "OK " + bytesToHex(buf);
    } finally {
      raf.close();
    }
  }
  
  if "get file * length" {
    File f = new File(assertAbsolutePath(m.unq(0)));
    ret str(f.length());
  }
  
  if "set file * length to *" {
    File f = new File(assertAbsolutePath(m.unq(0)));
    RandomAccessFile raf = new RandomAccessFile(f, "rw");
    try {
      raf.setLength(parseLong(m.unq(1)));
      ret "OK";
    } finally {
      raf.close();
    }
  }
    
  if "write file * bin from * data *" {
    print(shorten(s, 200));
    File f = new File(assertAbsolutePath(m.unq(0)));
    long from = parseLong(m.unq(1));
    byte[] data = hexToBytes(m.unq(2));
    if (l(data) > fileOpBot_maxWriteSize)
      fail(format("Can't write more than * bytes per call", fileOpBot_maxWriteSize));
    RandomAccessFile raf = new RandomAccessFile(f, "rw");
    try {
      raf.seek(from);
      raf.write(data);
      ret "OK";
    } finally {
      raf.close();
    }
  }
  
  null;
}