package DNA.Core;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.math.BigInteger;

import org.bouncycastle.crypto.params.ECPrivateKeyParameters;

import org.bouncycastle.crypto.signers.ECDSASigner;

import org.bouncycastle.util.BigIntegers;

import DNA.UInt160;

import DNA.Cryptography.*;

import DNA.IO.*;

import DNA.Wallets.Account;

/**

* 为需要签名的数据提供一个接口

*/

public interface Signable extends Serializable {

/**

* 反序列化未签名的数据

* <param name="reader">数据来源</param>

* @throws IOException

*/

void deserializeUnsigned(BinaryReader reader) throws IOException;

/**

* 序列化未签名的数据

* <param name="writer">存放序列化后的结果</param>

* @throws IOException

*/

void serializeUnsigned(BinaryWriter writer) throws IOException;

/**

* 获得需要校验的脚本Hash值

* <returns>返回需要校验的脚本Hash值</returns>

*/

UInt160[] getScriptHashesForVerifying();

default byte[] getHashData() {

try (ByteArrayOutputStream ms = new ByteArrayOutputStream()) {

try (BinaryWriter writer = new BinaryWriter(ms)) {

serializeUnsigned(writer);

writer.flush();

return ms.toByteArray();

}

} catch (IOException ex) {

throw new UnsupportedOperationException(ex);

}

}

default byte[] sign(Account account) {

ECDSASigner signer = new ECDSASigner();

signer.init(true, new ECPrivateKeyParameters(new BigInteger(1, account.privateKey), ECC.secp256r1));

BigInteger[] bi = signer.generateSignature(Digest.sha256(getHashData()));// dna

byte[] signature = new byte[64];

System.arraycopy(BigIntegers.asUnsignedByteArray(32, bi[0]), 0, signature, 0, 32);

System.arraycopy(BigIntegers.asUnsignedByteArray(32, bi[1]), 0, signature, 32, 32);

return signature;

}

default boolean verifySignature() {

return true;

}

}