package com.hx.util.rsa;

import com.hx.util.StringUtils;

import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.*;


/**
 * RSA签名验签类
 */
public class RSASignature{

    /**
     * 签名算法
     */
    public static final String SIGN_ALGORITHMS = "SHA1WithRSA";

    /**
     * RSA签名
     * @param content 待签名数据
     * @param privateKey 商户私钥
     * @param encode 字符集编码
     * @return 签名值
     */
    public static String createSign(String content, String privateKey, String encode) {
        try {
            PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec( Base64.decode(privateKey) );

            KeyFactory keyf = KeyFactory.getInstance("RSA");
            PrivateKey priKey = keyf.generatePrivate(priPKCS8);

            java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);

            signature.initSign(priKey);
            signature.update( content.getBytes(encode));

            byte[] signed = signature.sign();

            return Base64.encode(signed);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }

        return null;
    }

    public static String createSign(String content, String privateKey) {
        try{
            PKCS8EncodedKeySpec priPKCS8 	= new PKCS8EncodedKeySpec( Base64.decode(privateKey) );
            KeyFactory keyf = KeyFactory.getInstance("RSA");
            PrivateKey priKey = keyf.generatePrivate(priPKCS8);
            java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
            signature.initSign(priKey);
            signature.update( content.getBytes());
            byte[] signed = signature.sign();
            return Base64.encode(signed);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * RSA验签名检查
     * @param content 待签名数据
     * @param sign 签名值
     * @param publicKey 分配给开发商公钥
     * @param encode 字符集编码
     * @return 布尔值
     */
    public static boolean doCheck(String content, String sign, String publicKey,String encode) {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            byte[] encodedKey = Base64.decode(publicKey);
            PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));


            java.security.Signature signature = java.security.Signature
                    .getInstance(SIGN_ALGORITHMS);

            signature.initVerify(pubKey);
            signature.update( content.getBytes(encode) );

            boolean bverify = signature.verify( Base64.decode(sign) );
            return bverify;

        } catch (Exception e) {
            e.printStackTrace();
        }

        return false;
    }

    public static boolean doCheck(String content, String sign, String publicKey) {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            byte[] encodedKey = Base64.decode(publicKey);
            PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));


            java.security.Signature signature = java.security.Signature
                    .getInstance(SIGN_ALGORITHMS);

            signature.initVerify(pubKey);
            signature.update( content.getBytes() );

            boolean bverify = signature.verify( Base64.decode(sign) );
            return bverify;

        } catch (Exception e) {
            e.printStackTrace();
        }

        return false;
    }

    /**
     * ASCII码递增排序（剔除空值）
     * @param params
     * @return
     */
    public static String getSignCheckContent(Map<String, String> params) {
        if (params == null) {
            return null;
        } else {
            StringBuilder content = new StringBuilder();
            List<String> keys = new ArrayList(params.keySet());
            Collections.sort(keys);

            for(int i = 0; i < keys.size(); ++i) {
                String key = (String)keys.get(i);
                String value = String.valueOf(params.get(key));
                if(StringUtils.isEmpty(value)){
                    continue;
                }
                content.append(i == 0 ? "" : "&").append(key).append("=").append(value);
            }
            return content.toString();
        }
    }

}