package gnu.mapping;

public class WrongArguments extends IllegalArgumentException {
  //-- negative indicates that the right number of arguments was used
  public int number;
  //-- usage description for procedure
  public String usage;
  //-- Procedure name that threw the exception
  public String procname;

  Procedure proc;

  /** Returns an error message if the number of arguments in a call is invalid.
    * @param proc the Procedure being called
    * @param argCount the number of arguments in the call
    * @return null, if the number of arguments is ok;
    *     otherwise a suitable error message
    */
  public static String checkArgCount (Procedure proc, int argCount)
  {
    int num = proc.numArgs();
    int min = num & 0xfff;
    int max = num >> 12;
    String pname = proc.getName();
    if (pname == null)
      pname = proc.getClass().getName();
    return checkArgCount(pname, min, max, argCount);
  }

  public static String checkArgCount (String pname, int min, int max, int argCount)
  {
    boolean tooMany;
    if (argCount < min)
      tooMany = false;
    else if (max >= 0 && argCount > max)
      tooMany = true;
    else
      return null;
    StringBuffer buf = new StringBuffer(100);
    buf.append("call to '");
    buf.append(pname);
    buf.append("' has too ");
    buf.append(tooMany ? "many" : "few");
    buf.append(" arguments (");
    buf.append(argCount);
    if (min == max)
      {
	buf.append("; must be ");
	buf.append(min);
      }
    else
      {
	buf.append("; min=");
	buf.append(min);
	if (max >= 0)
	  {
	    buf.append(", max=");
	    buf.append(max);
	  }
      }
    buf.append(')');
    return buf.toString();
  }

  public String getMessage()
  {
    if (proc != null)
      {
	String msg = checkArgCount(proc, number);
	if (msg != null)
	  return msg;
      }
    return super.getMessage();
  }

  public WrongArguments(Procedure proc, int argCount)
  {
    this.proc = proc;
    number = argCount;
  }

   public WrongArguments(java.lang.String name,int n,java.lang.String u) {
      procname = name;
      number = n;
      usage = u;
   }
}
