package com.cescit.integrity;

import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.Signature;

import com.mabeijianxi.smallvideorecord2.Log;

import org.json.JSONObject;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

// apk完整性检验
class BaseIntegrity {

    private static final String MESSAGE_DIGEST_ALGORITHM = "SHA-256";

    // Collections.unmodifiableMap 使得返回的内容只能只读访问
    private static final Map<String, String> hashList = Collections.unmodifiableMap(
        new HashMap<String, String>()
    );

    public static JSONObject check(Context context) throws Exception {
        JSONObject result = new JSONObject();
        Map<String, String> nowHashList = getHashMap(context);

//        String ret = HttpUtil.getHttpRequestData((String) Config.getConfig(context,"APK_HASH_URL"),Config.getHeader(context));
//        JSONObject obj = new JSONObject(ret);
//        String upHash = obj.getString("apk");
        String upHash = Config.getConfig(context,"APK_HASH_KEY");
        String nowHash = nowHashList.get("apk");
        if (upHash==null || upHash.isEmpty() || !upHash.equals(nowHash)) {
            throw new Exception("Content of APK has been tampered");
        }
        result.put("res conunt", hashList.size());
        return result;
    }

//    // 获取文件对应的hash值
//    public static Map getHashMap(Context context) throws Exception{
//        File file = new File(context.getPackageCodePath());
//        InputStream fis = new FileInputStream(file);
//        String fileHash = getFileHash(fis);
//        // res资源（路径：文件hash）键值对
//        Map<String, String> nowHashList = new HashMap<String,String>();
//        Log.d(BaseIntegrity.class.getName(),"file hash: "+fileHash);
//        nowHashList.put("apk", fileHash);
//        return nowHashList;
//    }

    // 获取Res文件对应的hash值构造的String
    public static String getHashString(Context context) throws Exception{
        Map<String, String> nowHashList = getHashMap(context);
        String str = "";
        // 遍历对比文件hash
        for (Map.Entry<String, String> entry : nowHashList.entrySet()) {
            String fileName = entry.getKey();
            String presetHash = entry.getValue();
            if (!presetHash.equals("")) {
                str += "put(\"" + fileName + "\", \"" + presetHash + "\");";
            }
        }
        // 用默认字符编码解码字符串。
        byte[] bs = str.getBytes();
        str = new String(bs, StandardCharsets.UTF_8);
        return str;
    }

  private static Map<String, String> getHashMap(Context context) {
    PackageManager manager = context.getPackageManager();
    String pkgname = context.getPackageName();
    PackageInfo packageInfo = null;
    Map<String, String> nowHashList = new HashMap<String,String>();
    try {
      packageInfo = manager.getPackageInfo(pkgname, PackageManager.GET_SIGNATURES);
      Signature[] signatures = packageInfo.signatures;
      Signature sign = signatures[0];
      byte[] signByte = sign.toByteArray();
      nowHashList.put("apk", getHash(signByte));
    } catch (PackageManager.NameNotFoundException | IOException | NoSuchAlgorithmException e) {
    }
    return nowHashList;
  }

  private static String getHash(byte[] bytes) throws IOException, NoSuchAlgorithmException {
    byte[] buffer = new byte[1024]; // The buffer to read the file
    MessageDigest digest = MessageDigest.getInstance(MESSAGE_DIGEST_ALGORITHM);
    int numRead = 0; // Record how many bytes have been read
    digest.digest(bytes);
    byte [] sha1Bytes = digest.digest();
    StringBuffer hexString = new StringBuffer();
    for (int i = 0; i < sha1Bytes.length; i++) {
      hexString.append(Integer.toString(( sha1Bytes[i] & 0xff) + 0x100, 16).substring(1));
    }
    return new String(hexString);
  }
}