package civitas.crypto.parameters.encoder;
   
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.stereotype.Controller;
   
   import civitas.crypto.parameters.ElGamalParameters;
   import civitas.crypto.parameters.LegendreSymbol;
   import civitas.util.CivitasBigInteger;
   
  @Controller
  public class SafePrimeEncode {
  
  	@Autowired
  	LegendreSymbol legendreSymbol;
  
  	public CivitasBigInteger apply(final CivitasBigInteger x, final ElGamalParameters elGamalParameters) {
  		CivitasBigInteger encoding = x;
  		if (legendreSymbol.apply(encoding, elGamalParameters.p, elGamalParameters.q) == -1) {
  			encoding = elGamalParameters.p.subtract(encoding); // encoding = -m
  		}
  		return encoding;
  	}
  }