package com.kidgrow.jwt.utils;

import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

/**
 * 石家庄喜高科技有限责任公司 版权所有 © Copyright 2020<br>
 *
 * @Description: RsaKey 帮助类<br>
 * @Project: <br>
 * @CreateDate: Created in 2020/2/11 11:08 <br>
 * @Author: <a href="4345453@kidgrow.com">liuke</a>
 */
public class RsaKeyHelper {
    /**
     * 获取公钥,用于解析token
     *
     * @param filename
     * @return
     * @throws Exception
     */
    public PublicKey getPublicKey(String filename) throws IOException, NoSuchAlgorithmException, InvalidKeySpecException {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream(filename);
        try (DataInputStream dis = new DataInputStream(resourceAsStream)) {
            byte[] keyBytes = new byte[resourceAsStream.available()];
            dis.readFully(keyBytes);
            X509EncodedKeySpec spec = new X509EncodedKeySpec(keyBytes);
            KeyFactory kf = KeyFactory.getInstance("RSA");
            return kf.generatePublic(spec);
        }
    }

    /**
     * 获取密钥 用于生成token
     *
     * @param filename
     * @return
     * @throws Exception
     */
    public PrivateKey getPrivateKey(String filename) throws IOException, NoSuchAlgorithmException, InvalidKeySpecException {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream(filename);
        try (DataInputStream dis = new DataInputStream(resourceAsStream)) {
            byte[] keyBytes = new byte[resourceAsStream.available()];
            dis.readFully(keyBytes);

            PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
            KeyFactory kf = KeyFactory.getInstance("RSA");
            return kf.generatePrivate(spec);
        }
    }

}