/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.arialyy.aria.util;

import android.app.ActivityManager;
import android.content.Context;
import android.os.Build;
import android.os.Environment;
import android.os.StatFs;
import android.os.storage.StorageManager;
import android.os.storage.StorageVolume;
import android.text.TextUtils;
import com.arialyy.aria.core.AriaConfig;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Properties;
import java.util.Scanner;
import java.util.regex.Pattern;

/**
 * 文件操作工具类
 */
public class FileUtil {
  private static final String TAG = "FileUtil";
  private static final Pattern DIR_SEPORATOR = Pattern.compile("/");
  private static final String EXTERNAL_STORAGE_PATH =
      Environment.getExternalStorageDirectory().getPath();

  /**
   * 获取文件后缀名
   * @return 获取不到文件名后缀,返回null
   */
  public static String getFileExtensionName(String fileName) {
    if (TextUtils.isEmpty(fileName)) {
      return null;
    }
    int endP = fileName.lastIndexOf(".");
    return endP > -1 ? fileName.substring(endP + 1) : null;
  }

  /**
   * 通过流创建文件
   *
   * @param dest 输出路径
   */
  public static void createFileFormInputStream(InputStream is, String dest) {
    try {
      FileOutputStream fos = new FileOutputStream(dest);
      byte[] buf = new byte[1024];
      int len;
      while ((len = is.read(buf)) > 0) {
        fos.write(buf, 0, len);
      }
      is.close();
      fos.flush();
      fos.close();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  /**
   * 获取m3u8 ts文件的缓存目录。
   * 缓存文件夹格式:父文件夹/.文件名_码率
   *
   * @param path m3u8 文件下载路径
   * @return m3u8 ts文件的缓存目录
   */
  public static String getTsCacheDir(String path, int bandWidth) {
    if (TextUtils.isEmpty(path)) {
      throw new NullPointerException("m3u8文保存路径为空");
    }
    File file = new File(path);
    return String.format("%s/.%s_%s", file.getParent(), file.getName(), bandWidth);
  }

  /**
   * 创建目录 当目录不存在的时候创建文件,否则返回false
   */
  public static boolean createDir(String path) {
    File file = new File(path);
    if (!file.exists()) {
      if (!file.mkdirs()) {
        ALog.d(TAG, "创建失败,请检查路径和是否配置文件权限!");
        return false;
      }
      return true;
    }
    return false;
  }

  /**
   * 创建文件 当文件不存在的时候就创建一个文件。 如果文件存在,先删除原文件,然后重新创建一个新文件
   *
   * @return {@code true} 创建成功、{@code false} 创建失败
   */
  public static boolean createFile(String path) {
    if (TextUtils.isEmpty(path)) {
      ALog.e(TAG, "文件路径不能为null");
      return false;
    }
    return createFile(new File(path));
  }

  /**
   * 创建文件 当文件不存在的时候就创建一个文件。 如果文件存在,先删除原文件,然后重新创建一个新文件
   *
   * @return {@code true} 创建成功、{@code false} 创建失败
   */
  public static boolean createFile(File file) {
    if (file.getParentFile() == null || !file.getParentFile().exists()) {
      ALog.d(TAG, "目标文件所在路径不存在,准备创建……");
      if (!createDir(file.getParent())) {
        ALog.d(TAG, "创建目录文件所在的目录失败!文件路径【" + file.getPath() + "】");
      }
    }
    // 文件存在,删除文件
    deleteFile(file);
    try {
      if (file.createNewFile()) {
        //ALog.d(TAG, "创建文件成功:" + file.getAbsolutePath());
        return true;
      }
    } catch (IOException e) {
      e.printStackTrace();
      return false;
    }
    return false;
  }

  /**
   * 创建文件名,如果url链接有后缀名,则使用url中的后缀名
   *
   * @return url 的 hashKey
   */
  public static String createFileName(String url) {
    int end = url.indexOf("?");
    String tempUrl, fileName = "";
    if (end > 0) {
      tempUrl = url.substring(0, end);
      int tempEnd = tempUrl.lastIndexOf("/");
      if (tempEnd > 0) {
        fileName = tempUrl.substring(tempEnd + 1);
      }
    } else {
      int tempEnd = url.lastIndexOf("/");
      if (tempEnd > 0) {
        fileName = url.substring(tempEnd + 1);
      }
    }
    if (TextUtils.isEmpty(fileName)) {
      fileName = CommonUtil.keyToHashKey(url);
    }
    return fileName;
  }

  /**
   * 删除文件
   *
   * @param path 文件路径
   * @return {@code true}删除成功、{@code false}删除失败
   */
  public static boolean deleteFile(String path) {
    if (TextUtils.isEmpty(path)) {
      ALog.e(TAG, "删除文件失败,路径为空");
      return false;
    }
    return deleteFile(new File(path));
  }

  /**
   * 删除文件
   *
   * @param file 文件路径
   * @return {@code true}删除成功、{@code false}删除失败
   */
  public static boolean deleteFile(File file) {
    if (file.exists()) {
      final File to = new File(file.getAbsolutePath() + System.currentTimeMillis());
      if (file.renameTo(to)) {
        return to.delete();
      } else {
        return file.delete();
      }
    }
    return false;
  }

  /**
   * 删除文件夹
   */
  public static boolean deleteDir(File dirFile) {
    // 如果dir对应的文件不存在,则退出
    if (!dirFile.exists()) {
      return false;
    }

    if (dirFile.isFile()) {
      return dirFile.delete();
    } else {

      for (File file : dirFile.listFiles()) {
        deleteDir(file);
      }
    }

    return dirFile.delete();
  }

  /**
   * 将对象写入文件
   *
   * @param filePath 文件路径
   * @param data data数据必须实现{@link Serializable}接口
   */
  public static void writeObjToFile(String filePath, Object data) {
    if (!(data instanceof Serializable)) {
      ALog.e(TAG, "对象写入文件失败,data数据必须实现Serializable接口");
      return;
    }
    FileOutputStream ops = null;
    try {
      if (!createFile(filePath)) {
        return;
      }
      ops = new FileOutputStream(filePath);
      ObjectOutputStream oops = new ObjectOutputStream(ops);
      oops.writeObject(data);
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      if (ops != null) {
        try {
          ops.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    }
  }

  /**
   * 从文件中读取对象
   *
   * @param filePath 文件路径
   * @return 如果读取成功,返回相应的Obj对象,读取失败,返回null
   */
  public static Object readObjFromFile(String filePath) {
    if (TextUtils.isEmpty(filePath)) {
      ALog.e(TAG, "文件路径为空");
      return null;
    }
    File file = new File(filePath);
    if (!file.exists()) {
      ALog.e(TAG, String.format("文件【%s】不存在", filePath));
      return null;
    }
    FileInputStream fis = null;
    try {
      fis = new FileInputStream(filePath);
      ObjectInputStream oois = new ObjectInputStream(fis);
      return oois.readObject();
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } catch (ClassNotFoundException e) {
      e.printStackTrace();
    } finally {
      if (fis != null) {
        try {
          fis.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    }
    return null;
  }

  /**
   * 合并文件
   *
   * @param targetPath 目标文件
   * @param subPaths 碎片文件路径
   * @return {@code true} 合并成功,{@code false}合并失败
   */
  public static boolean mergeFile(String targetPath, List<String> subPaths) {
    File file = new File(targetPath);
    FileOutputStream fos = null;
    FileChannel foc = null;
    long startTime = System.currentTimeMillis();
    try {
      if (file.exists() && file.isDirectory()) {
        ALog.w(TAG, String.format("路径【%s】是文件夹,将删除该文件夹", targetPath));
        FileUtil.deleteDir(file);
      }
      if (!file.exists()) {
        FileUtil.createFile(file);
      }

      fos = new FileOutputStream(targetPath);
      foc = fos.getChannel();
      List<FileInputStream> streams = new LinkedList<>();
      long fileLen = 0;
      for (String subPath : subPaths) {
        File f = new File(subPath);
        if (!f.exists()) {
          ALog.d(TAG, String.format("合并文件失败,文件【%s】不存在", subPath));
          for (FileInputStream fis : streams) {
            fis.close();
          }
          streams.clear();

          return false;
        }
        FileInputStream fis = new FileInputStream(subPath);
        FileChannel fic = fis.getChannel();
        foc.transferFrom(fic, fileLen, f.length());
        fileLen += f.length();
        fis.close();
      }
      ALog.d(TAG, String.format("合并文件耗时:%sms", (System.currentTimeMillis() - startTime)));
      return true;
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      try {
        if (foc != null) {
          foc.close();
        }
        if (fos != null) {
          fos.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    return false;
  }

  /**
   * 合并sftp的分块文件,sftp的分块可能会超出规定的长度,因此需要使用本方法
   *
   * @param targetPath 目标文件
   * @param subPaths 碎片文件路径
   * @param targetFileSize 文件长度
   * @return {@code true} 合并成功,{@code false}合并失败
   */
  public static boolean mergeSFtpFile(String targetPath, List<String> subPaths,
      long targetFileSize) {
    File file = new File(targetPath);
    FileOutputStream fos = null;
    FileChannel foc = null;
    long startTime = System.currentTimeMillis();
    try {
      if (file.exists() && file.isDirectory()) {
        ALog.w(TAG, String.format("路径【%s】是文件夹,将删除该文件夹", targetPath));
        FileUtil.deleteDir(file);
      }
      if (!file.exists()) {
        FileUtil.createFile(file);
      }

      fos = new FileOutputStream(targetPath);
      foc = fos.getChannel();
      List<FileInputStream> streams = new LinkedList<>();
      int i = 0;
      int threadNum = subPaths.size();
      long tempLen = targetFileSize / threadNum;
      for (String subPath : subPaths) {
        File f = new File(subPath);
        if (!f.exists()) {
          ALog.d(TAG, String.format("合并文件失败,文件【%s】不存在", subPath));
          for (FileInputStream fis : streams) {
            fis.close();
          }
          streams.clear();

          return false;
        }

        long blockLen = i == (threadNum - 1) ? targetFileSize - tempLen * i : tempLen;
        FileInputStream fis = new FileInputStream(subPath);
        FileChannel fic = fis.getChannel();
        foc.transferFrom(fic, blockLen * i, blockLen);
        fis.close();
        i++;
      }

      ALog.d(TAG, String.format("合并文件耗时:%sms,合并后的文件长度:%s", (System.currentTimeMillis() - startTime),
          file.length()));
      return true;
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      try {
        if (foc != null) {
          foc.close();
        }
        if (fos != null) {
          fos.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    return false;
  }

  /**
   * 分割文件
   *
   * @param filePath 被分割的文件路径
   * @param num 分割的块数
   */
  public static void splitFile(String filePath, int num) {
    try {
      final File file = new File(filePath);
      long size = file.length();
      FileInputStream fis = new FileInputStream(file);
      FileChannel fic = fis.getChannel();
      long j = 0;
      long block = size / num;
      for (int i = 0; i < num; i++) {
        if (i == num - 1) {
          block = size - block * (num - 1);
        }
        String subPath = file.getPath() + "." + i + ".part";
        ALog.d(TAG, String.format("block = %s", block));
        File subFile = new File(subPath);
        if (!subFile.exists()) {
          createFile(subFile);
        }
        FileOutputStream fos = new FileOutputStream(subFile);
        FileChannel sfoc = fos.getChannel();
        ByteBuffer bf = ByteBuffer.allocate(8196);
        int len;
        //fis.skip(block * i);
        while ((len = fic.read(bf)) != -1) {
          bf.flip();
          sfoc.write(bf);
          bf.compact();
          j += len;
          if (j >= block * (i + 1)) {
            break;
          }
        }
        ALog.d(TAG, String.format("len = %s", subFile.length()));
        fos.close();
        sfoc.close();
      }
      fis.close();
      fic.close();
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  /**
   * 检查内存空间是否充足
   *
   * @param path 文件路径
   * @param fileSize 下载的文件的大小
   * @return true 空间足够
   */
  public static boolean checkMemorySpace(String path, long fileSize) {
    File temp = new File(path);
    if (!temp.exists()) {
      if (!temp.getParentFile().exists()) {
        FileUtil.createDir(temp.getParentFile().getPath());
      }
      path = temp.getParentFile().getPath();
    }

    StatFs stat = new StatFs(path);
    long blockSize = stat.getBlockSize();
    long availableBlocks = stat.getAvailableBlocks();
    return fileSize <= availableBlocks * blockSize;
  }

  /**
   * 读取下载配置文件
   */
  public static Properties loadConfig(File file) {
    Properties properties = new Properties();
    FileInputStream fis = null;
    if (!file.exists()) {
      createFile(file.getPath());
    }
    try {
      fis = new FileInputStream(file);
      properties.load(fis);
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      try {
        if (fis != null) {
          fis.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    return properties;
  }

  /**
   * 保存配置文件
   */
  public static void saveConfig(File file, Properties properties) {
    FileOutputStream fos = null;
    try {
      fos = new FileOutputStream(file, false);
      properties.store(fos, null);
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      try {
        if (fos != null) {
          fos.flush();
          fos.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }

  /**
   * 检查SD内存空间是否充足
   *
   * @param filePath 文件保存路径
   * @param fileSize 文件大小
   * @return {@code false} 内存空间不足,{@code true}内存空间足够
   */
  @Deprecated
  private static boolean checkSDMemorySpace(String filePath, long fileSize) {
    List<String> dirs = FileUtil.getSDPathList(AriaConfig.getInstance().getAPP());
    if (dirs == null || dirs.isEmpty()) {
      return true;
    }
    for (String path : dirs) {
      if (filePath.contains(path)) {
        if (fileSize > 0 && fileSize > getAvailableExternalMemorySize(path)) {
          return false;
        }
      }
    }
    return true;
  }

  /**
   * sdcard 可用大小
   *
   * @param sdcardPath sdcard 根路径
   * @return 单位为:byte
   */
  private static long getAvailableExternalMemorySize(String sdcardPath) {
    StatFs stat = new StatFs(sdcardPath);
    long blockSize = stat.getBlockSize();
    long availableBlocks = stat.getAvailableBlocks();
    return availableBlocks * blockSize;
  }

  /**
   * sdcard 总大小
   *
   * @param sdcardPath sdcard 根路径
   * @return 单位为:byte
   */
  private static long getTotalExternalMemorySize(String sdcardPath) {
    StatFs stat = new StatFs(sdcardPath);
    long blockSize = stat.getBlockSize();
    long totalBlocks = stat.getBlockCount();
    return totalBlocks * blockSize;
  }

  /**
   * 获取SD卡目录列表
   */
  private static List<String> getSDPathList(Context context) {
    List<String> paths = null;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
      try {
        paths = getVolumeList(context);
      } catch (NoSuchMethodException e) {
        e.printStackTrace();
      } catch (IllegalAccessException e) {
        e.printStackTrace();
      } catch (InvocationTargetException e) {
        e.printStackTrace();
      }
    } else {
      List<String> mounts = readMountsFile();
      List<String> volds = readVoldFile();
      paths = compareMountsWithVold(mounts, volds);
    }
    return paths;
  }

  /**
   * getSDPathList
   */
  private static List<String> getVolumeList(final Context context)
      throws NoSuchMethodException, InvocationTargetException,
      IllegalAccessException {
    List<String> pathList = new ArrayList<>();

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
      StorageManager manager = (StorageManager) context.getSystemService(Context.STORAGE_SERVICE);
      List<StorageVolume> volumes = manager.getStorageVolumes();

      Class<?> volumeClass = StorageVolume.class;
      Method getPath = volumeClass.getDeclaredMethod("getPath");
      //Method isRemovable = volumeClass.getDeclaredMethod("isRemovable");
      getPath.setAccessible(true);
      //isRemovable.setAccessible(true);

      for (StorageVolume volume : volumes) {
        String state = volume.getState();

        if (state.equals(Environment.MEDIA_MOUNTED)) {
          pathList.add((String) getPath.invoke(volume));
        }
      }
    } else {
      pathList.addAll(getStorageDirectories());
    }

    if (pathList.isEmpty()) {
      pathList = new ArrayList<>();
      pathList.add(EXTERNAL_STORAGE_PATH);
    }
    LinkedHashMap<Integer, String> paths = new LinkedHashMap<>();
    for (String path : pathList) {
      File root = new File(path);
      if (!root.exists() || !root.isDirectory() || !canWrite(path)) {
        continue;
      }
      //去除mount的相同目录
      int key = (root.getTotalSpace() + "-" + root.getUsableSpace()).hashCode();
      String prevPath = paths.get(key);
      if (!TextUtils.isEmpty(prevPath) && prevPath.length() < path.length()) {
        continue;
      }
      paths.put(key, path);
    }
    List<String> list = new ArrayList<>();
    for (Integer key : paths.keySet()) {
      list.add(paths.get(key));
    }
    return list;
  }

  private static boolean canWrite(String dirPath) {
    File dir = new File(dirPath);
    if (dir.canWrite()) {
      return true;
    }
    boolean canWrite;
    File testWriteFile = null;
    try {
      testWriteFile = new File(dirPath, "tw.txt");
      if (testWriteFile.exists()) {
        testWriteFile.delete();
      }
      testWriteFile.createNewFile();
      FileWriter writer = new FileWriter(testWriteFile);
      writer.write(1);
      writer.close();
      canWrite = true;
    } catch (Exception e) {
      e.printStackTrace();
      canWrite = false;
    } finally {
      try {
        if (testWriteFile != null && testWriteFile.exists()) {
          testWriteFile.delete();
        }
      } catch (Exception e) {
        e.printStackTrace();
      }
    }
    return canWrite;
  }

  /**
   * Raturns all available SD-Cards in the system (include emulated) Warning: Hack! Based on Android
   * source code of version 4.3
   * (API 18) Because there is no standard way to get it.
   * 4.2+
   *
   * @return paths to all available SD-Cards in the system (include emulated)
   */
  private static List<String> getStorageDirectories() {
    // Final set of paths
    final List<String> rv = new ArrayList<>();
    // Primary physical SD-CARD (not emulated)
    final String rawExternalStorage = System.getenv("EXTERNAL_STORAGE");
    // All Secondary SD-CARDs (all exclude primary) separated by ":"
    final String rawSecondaryStoragesStr = System.getenv("SECONDARY_STORAGE");
    // Primary emulated SD-CARD
    final String rawEmulatedStorageTarget = System.getenv("EMULATED_STORAGE_TARGET");
    if (TextUtils.isEmpty(rawEmulatedStorageTarget)) {
      // Device has physical external storage; use plain paths.
      if (TextUtils.isEmpty(rawExternalStorage)) {
        // EXTERNAL_STORAGE undefined; falling back to default.
        rv.add("/storage/sdcard0");
      } else {
        rv.add(rawExternalStorage);
      }
    } else {
      // Device has emulated storage; external storage paths should have
      // userId burned into them.
      final String rawUserId;

      //if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
      final String path = Environment.getExternalStorageDirectory().getAbsolutePath();
      final String[] folders = DIR_SEPORATOR.split(path);
      final String lastFolder = folders[folders.length - 1];
      boolean isDigit = false;
      if (!TextUtils.isEmpty(lastFolder) && TextUtils.isDigitsOnly(lastFolder)) {
        isDigit = true;
      }
      rawUserId = isDigit ? lastFolder : "";
      //} else {
      //  rawUserId = "";
      //}
      // /storage/emulated/0[1,2,...]
      if (TextUtils.isEmpty(rawUserId)) {
        rv.add(rawExternalStorage);
      } else {
        rv.add(rawEmulatedStorageTarget + File.separator + rawUserId);
      }
    }
    // Add all secondary storages
    if (!TextUtils.isEmpty(rawSecondaryStoragesStr)) {
      // All Secondary SD-CARDs splited into array
      final String[] rawSecondaryStorages = rawSecondaryStoragesStr.split(File.pathSeparator);
      Collections.addAll(rv, rawSecondaryStorages);
    }
    // checkout SD-CARDs writable
    for (int i = rv.size() - 1; i >= 0; i--) {
      String path = rv.get(i);
      File root = new File(path);
      if (!root.exists() || !root.isDirectory() || !canWrite(path)) {
        rv.remove(i);
      }
    }
    return rv;
  }

  /**
   * Scan the /proc/mounts file and look for lines like this: /dev/block/vold/179:1 /mnt/sdcard
   * vfat
   * rw,dirsync,nosuid,nodev,noexec ,relatime,uid=1000,gid=1015,fmask=0602,dmask=0602,allow_utime=0020,
   * codepage=cp437,iocharset= iso8859-1,shortname=mixed,utf8,errors=remount-ro 0 0 When one is
   * found, split it into its
   * elements and then pull out the path to the that mount point and add it to the arraylist
   */
  private static List<String> readMountsFile() {
    // some mount files don't list the default
    // path first, so we add it here to
    // ensure that it is first in our list
    List<String> mounts = new ArrayList<>();
    mounts.add(EXTERNAL_STORAGE_PATH);
    try {
      Scanner scanner = new Scanner(new File("/proc/mounts"));
      while (scanner.hasNext()) {
        String line = scanner.nextLine();
        if (line.startsWith("/dev/block/vold/") || line.startsWith("/dev/block//vold/")) {//
          String[] lineElements = line.split(" ");
          // String partition = lineElements[0];
          String element = lineElements[1];
          // don't add the default mount path
          // it's already in the list.
          if (!element.equals(EXTERNAL_STORAGE_PATH)) {
            mounts.add(element);
          }
        }
      }
      scanner.close();
    } catch (Exception e) {
      // e.printStackTrace();
    }
    return mounts;
  }

  private static List<String> readVoldFile() {
    // read /etc/vold.conf or /etc/vold.fstab (it depends on version what
    // clientConfig file is present)
    List<String> vold = null;
    Scanner scanner = null;
    try {
      try {
        scanner = new Scanner(new File("/system/etc/vold.fstab"));
      } catch (FileNotFoundException e1) {
        // e1.printStackTrace();
        scanner = new Scanner(new File("/system/etc/vold.conf"));
      }
      vold = new ArrayList<String>();
      vold.add(EXTERNAL_STORAGE_PATH);
      while (scanner.hasNext()) {
        String line = scanner.nextLine();
        if (TextUtils.isEmpty(line)) {
          continue;
        }
        line = line.trim();
        if (line.startsWith("dev_mount")) {
          String[] lineElements = line.split(" ");
          if (lineElements.length < 3) {
            continue;
          }
          String element = lineElements[2];
          if (element.contains(":")) {
            element = element.substring(0, element.indexOf(":"));
          }
          // ignore default path
          if (!element.equals(EXTERNAL_STORAGE_PATH)) {
            vold.add(element);
          }
        } else if (line.startsWith("mount_point")) {
          String element = line.replaceAll("mount_point", "").trim();
          if (!element.equals(EXTERNAL_STORAGE_PATH)) {
            vold.add(element);
          }
        }
      }
    } catch (Exception e) {
      // e.printStackTrace();
    }
    return vold;
  }

  private static List<String> compareMountsWithVold(List<String> mounts, List<String> volds) {
    /*
     * 有时候这两个list中的数据并不相同,我们只需要取两个list的交集部分。
     */
    for (int i = mounts.size() - 1; i >= 0; i--) {
      String mount = mounts.get(i);
      File root = new File(mount);
      // 判断目录是否存在并且可读
      if (!root.exists() || !root.isDirectory() || !root.canWrite()) {
        mounts.remove(i);
        continue;
      }
      if (volds != null && !volds.contains(mount)) {
        mounts.remove(i);
      }
    }
    // 清除无用数据
    if (volds != null) {
      volds.clear();
    }
    return mounts;
  }

  public static long getTotalMemory() {
    String file_path = "/proc/meminfo";// 系统内存信息文件
    String ram_info;
    String[] arrayOfRam;
    long initial_memory = 0L;
    try {
      FileReader fr = new FileReader(file_path);
      BufferedReader localBufferedReader = new BufferedReader(fr, 8192);
      // 读取meminfo第一行,系统总内存大小
      ram_info = localBufferedReader.readLine();
      arrayOfRam = ram_info.split("\\s+");// 实现多个空格切割的效果
      initial_memory =
          Integer.valueOf(arrayOfRam[1]) * 1024;// 获得系统总内存,单位是KB,乘以1024转换为Byte
      localBufferedReader.close();
    } catch (IOException e) {
      e.printStackTrace();
    }
    return initial_memory;
  }

  public static long getAvailMemory(Context context) {
    ActivityManager activityManager =
        (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    ActivityManager.MemoryInfo memoryInfo = new ActivityManager.MemoryInfo();
    activityManager.getMemoryInfo(memoryInfo);
    return memoryInfo.availMem;
  }
}