package com.yohoufo.common.utils;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

public class RSAUtils {
	public static final String SIGN_ALGORITHMS = "SHA1WithRSA";

    /**
     * RSA签名
     *
     * @param content       待签名数据
     * @param privateKey    商户私钥
     * @param input_charset 编码格式
     * @return 签名值
     */
    public static String sign(String content, String privateKey, String input_charset) {
        try {
            PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(Base64.decodeBase64(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(input_charset));

            byte[] signed = signature.sign();

            return Base64.encodeBase64String(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 ali_public_key 支付宝公钥
     * @param input_charset  编码格式
     * @return 布尔值
     */
    public static boolean verify(String content, String sign, String ali_public_key, String input_charset) {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            byte[] encodedKey = Base64.decodeBase64(ali_public_key);
            PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));


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

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

            boolean bverify = signature.verify(Base64.decodeBase64(sign));


            return bverify;

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

        return false;
    }


   /* public static void main(String[] args) {
        boolean hh = verify("app_id=2016091401906455&auth_app_id=2016091401906455&body=有货订单-967466860544&buyer_id=2088202230034730&buyer_logon_id=ma_***@126.com&buyer_pay_amount=0.01&charset=utf-8&fund_bill_list=[{\"amount\":\"0.01\",\"fundChannel\":\"ALIPAYACCOUNT\"}]&gmt_create=2018-09-28 21:16:37&gmt_payment=2018-09-28 21:16:38&invoice_amount=0.01&notify_id=2018092800222211638034730536853642&notify_time=2018-09-28 21:16:38&notify_type=trade_status_sync&out_trade_no=967466860544&point_amount=0.00&receipt_amount=0.01&seller_email=ouyin@yoho.cn&seller_id=2088421850636193&subject=有货订单-967466860544&total_amount=0.01&trade_no=2018092822001434730531453002&trade_status=TRADE_SUCCESS&version=1.0", "Ttg4ccpwuapdbtWv6GRoNGWFYqxvkm6QS1TV+5riZgOzehafhUnxup6jO+d0wZOT0vUkylUg/SUqwKHDqUCCl/XPPNVXEK2U8OFBZ/YrgekZkJ+p1IvwRgbbgeE2pGmzuDL7IiqAXidKzrr6dsLLM1YBMS2crVxLD2nL+WW449A=", "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDDI6d306Q8fIfCOaTXyiUeJHkrIvYISRcc73s3vF1ZT7XN8RNPwJxo8pWaJMmvyTn9N4HQ632qJBVHf8sxHi/fEsraprwCtzvzQETrNRwVxLO5jVmRGi60j8Ue1efIlzPXV9je9mkjzOmdssymZkh2QhUrCmZYI/FCEa3/cNMW0QIDAQAB", "utf-8");
        System.out.println(hh);
    }*/

    /**
     * 解密
     *
     * @param content       密文
     * @param private_key   商户私钥
     * @param input_charset 编码格式
     * @return 解密后的字符串
     */
    public static String decrypt(String content, String private_key, String input_charset) throws Exception {
        PrivateKey prikey = getPrivateKey(private_key);

        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, prikey);

        InputStream ins = new ByteArrayInputStream(Base64.decodeBase64(content));
        ByteArrayOutputStream writer = new ByteArrayOutputStream();
        //rsa解密的字节大小最多是128，将需要解密的内容，按128位拆开解密
        byte[] buf = new byte[128];
        int bufl;

        while ((bufl = ins.read(buf)) != -1) {
            byte[] block = null;

            if (buf.length == bufl) {
                block = buf;
            } else {
                block = new byte[bufl];
                for (int i = 0; i < bufl; i++) {
                    block[i] = buf[i];
                }
            }

            writer.write(cipher.doFinal(block));
        }

        return new String(writer.toByteArray(), input_charset);
    }


    /**
     * 得到私钥
     *
     * @param key 密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static PrivateKey getPrivateKey(String key) throws Exception {

        byte[] keyBytes;

        keyBytes = Base64.decodeBase64(key);

        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);

        KeyFactory keyFactory = KeyFactory.getInstance("RSA");

        PrivateKey privateKey = keyFactory.generatePrivate(keySpec);

        return privateKey;
    }
}