package civitas.common.votercapabilitysharesandproofs;
   
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.stereotype.Controller;
   
   import civitas.crypto.ciphertext.ElGamalCiphertext;
   import civitas.crypto.ciphertext.ElGamalEncrypt;
   import civitas.crypto.messagedigest.CryptoHash;
   import civitas.crypto.parameters.ElGamalParameters;
  import civitas.crypto.proofdvr.ElGamalProofDVR;
  import civitas.crypto.proofdvr.VerifyElGamalProofDVR;
  import civitas.crypto.publickey.ElGamalPublicKey;
  import civitas.crypto.reencryptfactor.ElGamalReencryptFactor;
  import civitas.crypto.signature.VerifyElGamalSignature;
  import civitas.crypto.signedciphertext.ElGamalSignedCiphertext;
  import civitas.crypto.votecapabilityshare.VoteCapabilityShare;
  import jakarta.annotation.Nonnull;
  
  @Controller
  public class VerifyVoterCapabilitySharesAndProof {
  
  	@Autowired
  	VerifyElGamalSignature verifyElGamalSignature;
  
  	@Autowired
  	CryptoHash cryptoHash;
  
  	@Autowired
  	ElGamalEncrypt elGamalEncrypt;
  
  	@Autowired
  	VerifyElGamalProofDVR verifyElGamalProofDVR;
  
  	public boolean apply(
  			@Nonnull final VoterCapabilitySharesAndProof that,
  			@Nonnull final ElGamalSignedCiphertext[] postedCapabilities,
  			@Nonnull final ElGamalPublicKey voterPublicKey,
  			@Nonnull final ElGamalPublicKey tabTellerSharedPublicKey,
  			final String voterName,
  			final int tellerIndex) {
  		if (null == voterPublicKey) {
  			throw new NullPointerException();
  		}
  		if (that.capabilities.length != that.rencryptFactors.length
  				|| that.capabilities.length != that.proofs.length
  				|| postedCapabilities.length != that.capabilities.length) {
  			return false;
  		}
  
  		ElGamalParameters params = tabTellerSharedPublicKey.params;
  		byte[] hash = cryptoHash.apply((tellerIndex + voterName).getBytes());
  
  		for (int i = 0; i < that.capabilities.length; i++) {
  			VoteCapabilityShare vc = that.capabilities[i];
  			ElGamalReencryptFactor r = that.rencryptFactors[i];
  			ElGamalProofDVR p = that.proofs[i];
  			if (!p.e().equals(postedCapabilities[i])
  					|| !verifyElGamalSignature.apply(params, postedCapabilities[i], hash)) {
  				return false;
  			}
  
  			ElGamalCiphertext encrypted = elGamalEncrypt.apply(tabTellerSharedPublicKey, vc, r);
  			if (!encrypted.equals(p.eprime())
  					|| !verifyElGamalProofDVR.apply(p, tabTellerSharedPublicKey, voterPublicKey)) {
  				return false;
  			}
  		}
  		return true;
  	}
  }