package com.example.server.sysOss.service;

import cn.hutool.core.io.IoUtil;
import com.example.client.entity.RenException;
import com.example.client.utils.UUIDUtil;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Primary;
import org.springframework.stereotype.Service;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import java.io.*;
import java.security.Key;
import java.security.SecureRandom;

@Primary
@Service
public class OssEncryptService {

    private static final String CIPHER_ALGORITHM = "AES";
    private static final String KEY = "zhpt-key#%W";

    private final Key secureKey;

    @Value("${zt.oss.local-path}")
    private String localPath;

    public OssEncryptService() {
        this.secureKey = getKey(KEY);
    }

    public Key getKey(String strKey) {
        try {
            if (strKey == null) {
                strKey = "";
            }
            KeyGenerator _generator = KeyGenerator.getInstance(CIPHER_ALGORITHM);
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
            secureRandom.setSeed(strKey.getBytes());
            _generator.init(128, secureRandom);
            return _generator.generateKey();
        } catch (Exception e) {
           throw new RenException("密钥生成异常");
        }
    }

    public InputStream encryptStream(InputStream inputStream, Key key) throws Exception {
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, key);
        String tempUploadDir = localPath + "TEMP_UPLOAD" + File.separator + "TEMP_FILE";
        File dir = new File(tempUploadDir);
        if (!dir.exists()) {
            dir.mkdirs();
        }
        dir = new File(tempUploadDir);
        // 创建临时文件来保存加密后的数据
        File tempFile = File.createTempFile(UUIDUtil.generateId().toString(), ".tmp", dir);
        FileOutputStream outputStream = new FileOutputStream(tempFile);

        byte[] buffer = new byte[8192];
        int bytesRead;

        try {
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                byte[] encryptedBytes = cipher.update(buffer, 0, bytesRead);
                outputStream.write(encryptedBytes);
            }

            byte[] finalEncryptedBytes = cipher.doFinal();
            outputStream.write(finalEncryptedBytes);
        } finally {
            // 关闭资源
            try {
                inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                outputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        // 返回临时文件的输入流
        return new FileInputStream(tempFile);
    }

    public InputStream decryptStream(File file, Key key) throws Exception {

        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, key);

        // 创建临时文件来保存解密后的数据
        String tempUploadDir = localPath + "TEMP_UPLOAD" + File.separator + "TEMP_FILE";
        File dir = new File(tempUploadDir);
        if (!dir.exists()) {
            dir.mkdirs();
        }
        dir = new File(tempUploadDir);
        // 创建临时文件来保存加密后的数据
        File tempFile = File.createTempFile(UUIDUtil.generateId().toString(), ".tmp", dir);
        FileOutputStream outputStream = new FileOutputStream(tempFile);

        FileInputStream fileInputStream = new FileInputStream(file);
        BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream);

        byte[] buffer = new byte[8192];
        int bytesRead;

        try {
            while ((bytesRead = bufferedInputStream.read(buffer)) != -1) {
                byte[] decryptedBytes = cipher.update(buffer, 0, bytesRead);
                outputStream.write(decryptedBytes);
            }
            byte[] finalDecryptedBytes = cipher.doFinal();
            outputStream.write(finalDecryptedBytes);
        } finally {
            // 关闭资源
            try {
                bufferedInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                fileInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                outputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        // 返回临时文件的输入流
        return new FileInputStream(tempFile);
    }
}