package civitas.crypto.votecapabilityshare;
   
   import civitas.crypto.parameters.ElGamalParameters;
   import civitas.crypto.votecapability.VoteCapability;
   import civitas.util.CivitasBigInteger;
   
   public class CombineVoteCapabilityShares {
   
   	public VoteCapability[] apply(final VoteCapabilityShare[][] shares, final ElGamalParameters params) {
  		if (shares == null || shares[0] == null) {
  			return new VoteCapability[0];
  		}
  
  		CivitasBigInteger[] product = new CivitasBigInteger[shares[0].length];
  		for (VoteCapabilityShare[] share : shares) {
  			for (int index = 0; index < share.length; index++) {
  				VoteCapabilityShare s = share[index];
  				if (product[index] == null) {
  					product[index] = s.m();
  				} else {
  					product[index] = product[index].modMultiply(s.m(), params.p);
  				}
  			}
  		}
  		VoteCapability[] capabilities = new VoteCapability[product.length];
  		for (int index = 0; index < product.length; index++) {
  			capabilities[index] = new VoteCapability(product[index]);
  		}
  		return capabilities;
  	}
  }