package com.xy.jx.util;

import android.util.Log;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
/**
 * Created by xuxiang on 2017/6/10.
 */
public class FileAESUtil {
    /**
     * 加密用的Key 可以用26个字母和数字组成 此处使用AES-128-CBC加密模式，key需要为16位。
     **/
    private static String sKey = "写入您的加密key";//key，可自行修改
    private static String ivParameter = "写入您的偏移量";//偏移量,可自行修改
    /**
     * 算法/模式/填充
     **/
    private static final String CipherMode = "AES/CBC/PKCS5Padding";
    /**
     * 加密文件
     * @param readPath  源文件路径
     * @param writePath 加密后文件路径
     */
    public static void setAESFile(String readPath, String writePath) {
        File file = new File(readPath);
        if(!file.exists()) return;
        File writeFile = new File(writePath);
        InputStream inputStream = null;
        OutputStream outputStream = null;
        byte bt[] = new byte[(int) file.length()];
        try {
            if(!writeFile.exists()) writeFile.createNewFile();
            inputStream = new FileInputStream(file);
            outputStream = new FileOutputStream(writeFile);
            int byteread = 0;
            // 读入多个字节到字节数组中，byteread为一次读入的字节数
            while ((byteread = inputStream.read(bt)) != -1) {
                outputStream.write(encrypt(bt));
                outputStream.flush();
            }
            file.delete();
        }catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if(outputStream != null)
                    outputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (inputStream != null)
                    inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    /**
     * 解密文件
     * @param readPath   源文件路径
     * @param writePath  解密后文件路径
     */
    public static File readAESFile(String readPath, String writePath) {
        File file = new File(readPath);
        if(!file.exists()) return null;
        File writeFile = new File(writePath);
        InputStream inputStream = null;
        OutputStream outputStream = null;
        byte bt[] = new byte[(int) file.length()];
        try {
            if(!writeFile.exists()) writeFile.createNewFile();
            inputStream = new FileInputStream(file);
            outputStream = new FileOutputStream(writeFile);
            int byteread = 0;
            // 读入多个字节到字节数组中，byteread为一次读入的字节数
            while ((byteread = inputStream.read(bt)) != -1) {
                byte[] decrypt = decrypt(bt);
                Log.e("length", "decrypt ======" + decrypt.length);
                outputStream.write(decrypt);
                outputStream.flush();
            }
            return writeFile;
        }catch (IOException e) {
            e.printStackTrace();
            return null;
        } finally {
            try {
                if(outputStream != null)
                    outputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (inputStream != null)
                    inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    // 加密
    public static byte[] encrypt(byte[] bytes) {
        try {
            Cipher cipher = Cipher.getInstance(CipherMode);
            byte[] raw = sKey.getBytes();
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
            IvParameterSpec iv = new IvParameterSpec(ivParameter.getBytes());// 使用CBC模式，需要一个向量iv，可增加加密算法的强度
            cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
            byte[] encrypted = cipher.doFinal(bytes);
            return encrypted;
        } catch (Exception ex) {
            Log.e("AES", "加密异常：" + ex.getMessage());
            return null;
        }
    }
    // 解密
    public static byte[] decrypt(byte[] bytes) {
        try {
            byte[] raw = sKey.getBytes("ASCII");
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
            Cipher cipher = Cipher.getInstance(CipherMode);
            IvParameterSpec iv = new IvParameterSpec(ivParameter.getBytes());
            cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
            //byte[] encrypted1 = new BASE64Decoder().decodeBuffer(new String(bytes, "utf-8"));// 先用base64解密
            byte[] original = cipher.doFinal(bytes);
            return original;
        } catch (Exception ex) {
            Log.e("AES", "解密异常：" + ex.getMessage());
            return null;
        }
    }
}