content: package com.termux.shared.termux.file;
  
  import static com.termux.shared.termux.TermuxConstants.TERMUX_PREFIX_DIR_PATH;
  
  import android.content.Context;
  import android.os.Environment;
  
  import androidx.annotation.NonNull;
  
  import com.termux.shared.file.FileUtils;
  import com.termux.shared.logger.Logger;
  import com.termux.shared.markdown.MarkdownUtils;
  import com.termux.shared.shell.command.ExecutionCommand;
  import com.termux.shared.errors.Error;
  import com.termux.shared.file.FileUtilsErrno;
  import com.termux.shared.termux.shell.command.environment.TermuxShellEnvironment;
  import com.termux.shared.shell.command.runner.app.AppShell;
  import com.termux.shared.android.AndroidUtils;
  import com.termux.shared.termux.TermuxConstants;
  import com.termux.shared.termux.TermuxUtils;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.regex.Pattern;
  
  public class TermuxFileUtils {
  
      private static final String LOG_TAG = "TermuxFileUtils";
  
      /**
       * Replace "$PREFIX/" or "~/" prefix with termux absolute paths.
       *
       * @param paths The {@code paths} to expand.
       * @return Returns the {@code expand paths}.
       */
      public static List<String> getExpandedTermuxPaths(List<String> paths) {
          if (paths == null) return null;
          List<String> expandedPaths = new ArrayList<>();
  
          for (int i = 0; i < paths.size(); i++) {
              expandedPaths.add(getExpandedTermuxPath(paths.get(i)));
          }
  
          return expandedPaths;
      }
  
      /**
       * Replace "$PREFIX/" or "~/" prefix with termux absolute paths.
       *
       * @param path The {@code path} to expand.
       * @return Returns the {@code expand path}.
       */
      public static String getExpandedTermuxPath(String path) {
          if (path != null && !path.isEmpty()) {
              path = path.replaceAll("^\\$PREFIX$", TermuxConstants.TERMUX_PREFIX_DIR_PATH);
              path = path.replaceAll("^\\$PREFIX/", TermuxConstants.TERMUX_PREFIX_DIR_PATH + "/");
              path = path.replaceAll("^~/$", TermuxConstants.TERMUX_HOME_DIR_PATH);
              path = path.replaceAll("^~/", TermuxConstants.TERMUX_HOME_DIR_PATH + "/");
          }
  
          return path;
      }
  
      /**
       * Replace termux absolute paths with "$PREFIX/" or "~/" prefix.
       *
       * @param paths The {@code paths} to unexpand.
       * @return Returns the {@code unexpand paths}.
       */
      public static List<String> getUnExpandedTermuxPaths(List<String> paths) {
          if (paths == null) return null;
          List<String> unExpandedPaths = new ArrayList<>();
  
          for (int i = 0; i < paths.size(); i++) {
              unExpandedPaths.add(getUnExpandedTermuxPath(paths.get(i)));
          }
  
          return unExpandedPaths;
      }
  
      /**
       * Replace termux absolute paths with "$PREFIX/" or "~/" prefix.
       *
       * @param path The {@code path} to unexpand.
       * @return Returns the {@code unexpand path}.
       */
      public static String getUnExpandedTermuxPath(String path) {
          if (path != null && !path.isEmpty()) {
              path = path.replaceAll("^" + Pattern.quote(TermuxConstants.TERMUX_PREFIX_DIR_PATH) + "/", "\\$PREFIX/");
              path = path.replaceAll("^" + Pattern.quote(TermuxConstants.TERMUX_HOME_DIR_PATH) + "/", "~/");
          }
  
          return path;
      }
  
      /**
       * Get canonical path.
       *
       * @param path The {@code path} to convert.
       * @param prefixForNonAbsolutePath Optional prefix path to prefix before non-absolute paths. This
       *                                 can be set to {@code null} if non-absolute paths should
       *                                 be prefixed with "/". The call to {@link File#getCanonicalPath()}
       *                                 will automatically do this anyways.
       * @param expandPath The {@code boolean} that decides if input path is first attempted to be expanded by calling
       *                   {@link TermuxFileUtils#getExpandedTermuxPath(String)} before its passed to
       *                   {@link FileUtils#getCanonicalPath(String, String)}.
  
       * @return Returns the {@code canonical path}.
       */
      public static String getCanonicalPath(String path, final String prefixForNonAbsolutePath, final boolean expandPath) {
          if (path == null) path = "";
  
          if (expandPath)
              path = getExpandedTermuxPath(path);
  
          return FileUtils.getCanonicalPath(path, prefixForNonAbsolutePath);
      }
  
      /**
       * Check if {@code path} is under the allowed termux working directory paths. If it is, then
       * allowed parent path is returned.
       *
       * @param path The {@code path} to check.
       * @return Returns the allowed path if it {@code path} is under it, otherwise {@link TermuxConstants#TERMUX_FILES_DIR_PATH}.
       */
      public static String getMatchedAllowedTermuxWorkingDirectoryParentPathForPath(String path) {
          if (path == null || path.isEmpty()) return TermuxConstants.TERMUX_FILES_DIR_PATH;
  
          if (path.startsWith(TermuxConstants.TERMUX_STORAGE_HOME_DIR_PATH + "/")) {
              return TermuxConstants.TERMUX_STORAGE_HOME_DIR_PATH;
          } if (path.startsWith(Environment.getExternalStorageDirectory().getAbsolutePath() + "/")) {
              return Environment.getExternalStorageDirectory().getAbsolutePath();
          } else if (path.startsWith("/sdcard/")) {
              return "/sdcard";
          } else {
              return TermuxConstants.TERMUX_FILES_DIR_PATH;
          }
      }
  
      /**
       * Validate the existence and permissions of directory file at path as a working directory for
       * termux app.
       *
       * The creation of missing directory and setting of missing permissions will only be done if
       * {@code path} is under paths returned by {@link #getMatchedAllowedTermuxWorkingDirectoryParentPathForPath(String)}.
       *
       * The permissions set to directory will be {@link FileUtils#APP_WORKING_DIRECTORY_PERMISSIONS}.
       *
       * @param label The optional label for the directory file. This can optionally be {@code null}.
       * @param filePath The {@code path} for file to validate or create. Symlinks will not be followed.
       * @param createDirectoryIfMissing The {@code boolean} that decides if directory file
       *                                 should be created if its missing.
       * @param setPermissions The {@code boolean} that decides if permissions are to be
       *                              automatically set defined by {@code permissionsToCheck}.
       * @param setMissingPermissionsOnly The {@code boolean} that decides if only missing permissions
       *                                  are to be set or if they should be overridden.
       * @param ignoreErrorsIfPathIsInParentDirPath The {@code boolean} that decides if existence
       *                                  and permission errors are to be ignored if path is
       *                                  in {@code parentDirPath}.
       * @param ignoreIfNotExecutable The {@code boolean} that decides if missing executable permission
       *                              error is to be ignored. This allows making an attempt to set
       *                              executable permissions, but ignoring if it fails.
       * @return Returns the {@code error} if path is not a directory file, failed to create it,
       * or validating permissions failed, otherwise {@code null}.
       */
      public static Error validateDirectoryFileExistenceAndPermissions(String label, final String filePath, final boolean createDirectoryIfMissing,
                                                                       final boolean setPermissions, final boolean setMissingPermissionsOnly,
                                                                       final boolean ignoreErrorsIfPathIsInParentDirPath, final boolean ignoreIfNotExecutable) {
          return FileUtils.validateDirectoryFileExistenceAndPermissions(label, filePath,
              TermuxFileUtils.getMatchedAllowedTermuxWorkingDirectoryParentPathForPath(filePath), createDirectoryIfMissing,
              FileUtils.APP_WORKING_DIRECTORY_PERMISSIONS, setPermissions, setMissingPermissionsOnly,
              ignoreErrorsIfPathIsInParentDirPath, ignoreIfNotExecutable);
      }
  
      /**
       * Validate if {@link TermuxConstants#TERMUX_FILES_DIR_PATH} exists and has
       * {@link FileUtils#APP_WORKING_DIRECTORY_PERMISSIONS} permissions.
       *
       * This is required because binaries compiled for termux are hard coded with
       * {@link TermuxConstants#TERMUX_PREFIX_DIR_PATH} and the path must be accessible.
       *
       * The permissions set to directory will be {@link FileUtils#APP_WORKING_DIRECTORY_PERMISSIONS}.
       *
       * This function does not create the directory manually but by calling {@link Context#getFilesDir()}
       * so that android itself creates it. However, the call will not create its parent package
       * data directory `/data/user/0/[package_name]` if it does not already exist and a `logcat`
       * error will be logged by android.
       * {@code Failed to ensure /data/user/0/<package_name>/files: mkdir failed: ENOENT (No such file or directory)}
       * An android app normally can't create the package data directory since its parent `/data/user/0`
       * is owned by `system` user and is normally created at app install or update time and not at app startup.
       *
       * Note that the path returned by {@link Context#getFilesDir()} may
       * be under `/data/user/[id]/[package_name]` instead of `/data/data/[package_name]`
       * defined by default by {@link TermuxConstants#TERMUX_FILES_DIR_PATH} where id will be 0 for
       * primary user and a higher number for other users/profiles. If app is running under work profile
       * or secondary user, then {@link TermuxConstants#TERMUX_FILES_DIR_PATH} will not be accessible
       * and will not be automatically created, unless there is a bind mount from `/data/data` to
       * `/data/user/[id]`, ideally in the right namespace.
       * https://source.android.com/devices/tech/admin/multi-user
       *
       *
       * On Android version `<=10`, the `/data/user/0` is a symlink to `/data/data` directory.
       * https://cs.android.com/android/platform/superproject/+/android-10.0.0_r47:system/core/rootdir/init.rc;l=589
       * {@code
       * symlink /data/data /data/user/0
       * }
       *
       * {@code
       * /system/bin/ls -lhd /data/data /data/user/0
       * drwxrwx--x 179 system system 8.0K 2021-xx-xx xx:xx /data/data
       * lrwxrwxrwx   1 root   root     10 2021-xx-xx xx:xx /data/user/0 -> /data/data
       * }
       *
       * On Android version `>=11`, the `/data/data` directory is bind mounted at `/data/user/0`.
       * https://cs.android.com/android/platform/superproject/+/android-11.0.0_r40:system/core/rootdir/init.rc;l=705
       * https://cs.android.com/android/_/android/platform/system/core/+/3cca270e95ca8d8bc8b800e2b5d7da1825fd7100
       * {@code
       * # Unlink /data/user/0 if we previously symlink it to /data/data
       * rm /data/user/0
       *
       * # Bind mount /data/user/0 to /data/data
       * mkdir /data/user/0 0700 system system encryption=None
       * mount none /data/data /data/user/0 bind rec
       * }
       *
       * {@code
       * /system/bin/grep -E '( /data )|( /data/data )|( /data/user/[0-9]+ )' /proc/self/mountinfo 2>&1 | /system/bin/grep -v '/data_mirror' 2>&1
       * 87 32 253:5 / /data rw,nosuid,nodev,noatime shared:27 - ext4 /dev/block/dm-5 rw,seclabel,resgid=1065,errors=panic
       * 91 87 253:5 /data /data/user/0 rw,nosuid,nodev,noatime shared:27 - ext4 /dev/block/dm-5 rw,seclabel,resgid=1065,errors=panic
       * }
       *
       * The column 4 defines the root of the mount within the filesystem.
       * Basically, `/dev/block/dm-5/` is mounted at `/data` and `/dev/block/dm-5/data` is mounted at
       * `/data/user/0`.
       * https://www.kernel.org/doc/Documentation/filesystems/proc.txt (section 3.5)
       * https://www.kernel.org/doc/Documentation/filesystems/sharedsubtree.txt
       * https://unix.stackexchange.com/a/571959
       *
       *
       * Also note that running `/system/bin/ls -lhd /data/user/0/com.termux` as secondary user will result
       * in `ls: /data/user/0/com.termux: Permission denied` where `0` is primary user id but running
       * `/system/bin/ls -lhd /data/user/10/com.termux` will result in
       * `drwx------ 6 u10_a149 u10_a149 4.0K 2021-xx-xx xx:xx /data/user/10/com.termux` where `10` is
       * secondary user id. So can't stat directory (not contents) of primary user from secondary user
       * but can the other way around. However, this is happening on android 10 avd, but not on android
       * 11 avd.
       *
       * @param context The {@link Context} for operations.
       * @param createDirectoryIfMissing The {@code boolean} that decides if directory file
       *                                 should be created if its missing.
       * @param setMissingPermissions The {@code boolean} that decides if permissions are to be
       *                              automatically set.
       * @return Returns the {@code error} if path is not a directory file, failed to create it,
       * or validating permissions failed, otherwise {@code null}.
       */
      public static Error isTermuxFilesDirectoryAccessible(@NonNull final Context context, boolean createDirectoryIfMissing, boolean setMissingPermissions) {
          if (createDirectoryIfMissing)
              context.getFilesDir();
  
          if (!FileUtils.directoryFileExists(TermuxConstants.TERMUX_FILES_DIR_PATH, true))
              return FileUtilsErrno.ERRNO_FILE_NOT_FOUND_AT_PATH.getError("termux files directory", TermuxConstants.TERMUX_FILES_DIR_PATH);
  
          if (setMissingPermissions)
              FileUtils.setMissingFilePermissions("termux files directory", TermuxConstants.TERMUX_FILES_DIR_PATH,
                  FileUtils.APP_WORKING_DIRECTORY_PERMISSIONS);
  
          return FileUtils.checkMissingFilePermissions("termux files directory", TermuxConstants.TERMUX_FILES_DIR_PATH,
              FileUtils.APP_WORKING_DIRECTORY_PERMISSIONS, false);
      }
  
      /**
       * Validate if {@link TermuxConstants#TERMUX_PREFIX_DIR_PATH} exists and has
       * {@link FileUtils#APP_WORKING_DIRECTORY_PERMISSIONS} permissions.
       * .
       *
       * The {@link TermuxConstants#TERMUX_PREFIX_DIR_PATH} directory would not exist if termux has
       * not been installed or the bootstrap setup has not been run or if it was deleted by the user.
       *
       * @param createDirectoryIfMissing The {@code boolean} that decides if directory file
       *                                 should be created if its missing.
       * @param setMissingPermissions The {@code boolean} that decides if permissions are to be
       *                              automatically set.
       * @return Returns the {@code error} if path is not a directory file, failed to create it,
       * or validating permissions failed, otherwise {@code null}.
       */
      public static Error isTermuxPrefixDirectoryAccessible(boolean createDirectoryIfMissing, boolean setMissingPermissions) {
             return FileUtils.validateDirectoryFileExistenceAndPermissions("termux prefix directory", TermuxConstants.TERMUX_PREFIX_DIR_PATH,
                  null, createDirectoryIfMissing,
                  FileUtils.APP_WORKING_DIRECTORY_PERMISSIONS, setMissingPermissions, true,
                  false, false);
      }
  
      /**
       * Validate if {@link TermuxConstants#TERMUX_STAGING_PREFIX_DIR_PATH} exists and has
       * {@link FileUtils#APP_WORKING_DIRECTORY_PERMISSIONS} permissions.
       *
       * @param createDirectoryIfMissing The {@code boolean} that decides if directory file
       *                                 should be created if its missing.
       * @param setMissingPermissions The {@code boolean} that decides if permissions are to be
       *                              automatically set.
       * @return Returns the {@code error} if path is not a directory file, failed to create it,
       * or validating permissions failed, otherwise {@code null}.
       */
      public static Error isTermuxPrefixStagingDirectoryAccessible(boolean createDirectoryIfMissing, boolean setMissingPermissions) {
          return FileUtils.validateDirectoryFileExistenceAndPermissions("termux prefix staging directory", TermuxConstants.TERMUX_STAGING_PREFIX_DIR_PATH,
              null, createDirectoryIfMissing,
              FileUtils.APP_WORKING_DIRECTORY_PERMISSIONS, setMissingPermissions, true,
              false, false);
      }
  
      /**
       * Validate if {@link TermuxConstants.TERMUX_APP#APPS_DIR_PATH} exists and has
       * {@link FileUtils#APP_WORKING_DIRECTORY_PERMISSIONS} permissions.
       *
       * @param createDirectoryIfMissing The {@code boolean} that decides if directory file
       *                                 should be created if its missing.
       * @param setMissingPermissions The {@code boolean} that decides if permissions are to be
       *                              automatically set.
       * @return Returns the {@code error} if path is not a directory file, failed to create it,
       * or validating permissions failed, otherwise {@code null}.
       */
      public static Error isAppsTermuxAppDirectoryAccessible(boolean createDirectoryIfMissing, boolean setMissingPermissions) {
          return FileUtils.validateDirectoryFileExistenceAndPermissions("apps/termux-app directory", TermuxConstants.TERMUX_APP.APPS_DIR_PATH,
              null, createDirectoryIfMissing,
              FileUtils.APP_WORKING_DIRECTORY_PERMISSIONS, setMissingPermissions, true,
              false, false);
      }
  
      /**
       * If {@link TermuxConstants#TERMUX_PREFIX_DIR_PATH} doesn't exist, is empty or only contains
       * files in {@link TermuxConstants#TERMUX_PREFIX_DIR_IGNORED_SUB_FILES_PATHS_TO_CONSIDER_AS_EMPTY}.
       */
      public static boolean isTermuxPrefixDirectoryEmpty() {
          Error error = FileUtils.validateDirectoryFileEmptyOrOnlyContainsSpecificFiles("termux prefix",
              TERMUX_PREFIX_DIR_PATH, TermuxConstants.TERMUX_PREFIX_DIR_IGNORED_SUB_FILES_PATHS_TO_CONSIDER_AS_EMPTY, true);
          if (error == null)
              return true;
  
          if (!FileUtilsErrno.ERRNO_NON_EMPTY_DIRECTORY_FILE.equalsErrorTypeAndCode(error))
              Logger.logErrorExtended(LOG_TAG, "Failed to check if termux prefix directory is empty:\n" + error.getErrorLogString());
          return false;
      }
  
      /**
       * Get a markdown {@link String} for stat output for various Termux app files paths.
       *
       * @param context The context for operations.
       * @return Returns the markdown {@link String}.
       */
      public static String getTermuxFilesStatMarkdownString(@NonNull final Context context) {
          Context termuxPackageContext = TermuxUtils.getTermuxPackageContext(context);
          if (termuxPackageContext == null) return null;
  
          // Also ensures that termux files directory is created if it does not already exist
          String filesDir = termuxPackageContext.getFilesDir().getAbsolutePath();
  
          // Build script
          StringBuilder statScript = new StringBuilder();
          statScript
              .append("echo 'ls info:'\n")
              .append("/system/bin/ls -lhdZ")
              .append(" '/data/data'")
              .append(" '/data/user/0'")
              .append(" '" + TermuxConstants.TERMUX_INTERNAL_PRIVATE_APP_DATA_DIR_PATH + "'")
              .append(" '/data/user/0/" + TermuxConstants.TERMUX_PACKAGE_NAME + "'")
              .append(" '" + TermuxConstants.TERMUX_FILES_DIR_PATH + "'")
              .append(" '" + filesDir + "'")
              .append(" '/data/user/0/" + TermuxConstants.TERMUX_PACKAGE_NAME + "/files'")
              .append(" '/data/user/" + TermuxConstants.TERMUX_PACKAGE_NAME + "/files'")
              .append(" '" + TermuxConstants.TERMUX_STAGING_PREFIX_DIR_PATH + "'")
              .append(" '" + TermuxConstants.TERMUX_PREFIX_DIR_PATH + "'")
              .append(" '" + TermuxConstants.TERMUX_HOME_DIR_PATH + "'")
              .append(" '" + TermuxConstants.TERMUX_BIN_PREFIX_DIR_PATH + "/login'")
              .append(" 2>&1")
              .append("\necho; echo 'mount info:'\n")
              .append("/system/bin/grep -E '( /data )|( /data/data )|( /data/user/[0-9]+ )' /proc/self/mountinfo 2>&1 | /system/bin/grep -v '/data_mirror' 2>&1");
  
          // Run script
          ExecutionCommand executionCommand = new ExecutionCommand(-1, "/system/bin/sh", null,
              statScript.toString() + "\n", "/", ExecutionCommand.Runner.APP_SHELL.getName(), true);
          executionCommand.commandLabel = TermuxConstants.TERMUX_APP_NAME + " Files Stat Command";
          executionCommand.backgroundCustomLogLevel = Logger.LOG_LEVEL_OFF;
          AppShell appShell = AppShell.execute(context, executionCommand, null, new TermuxShellEnvironment(), null, true);
          if (appShell == null || !executionCommand.isSuccessful()) {
              Logger.logErrorExtended(LOG_TAG, executionCommand.toString());
              return null;
          }
  
          // Build script output
          StringBuilder statOutput = new StringBuilder();
          statOutput.append("$ ").append(statScript.toString());
          statOutput.append("\n\n").append(executionCommand.resultData.stdout.toString());
  
          boolean stderrSet = !executionCommand.resultData.stderr.toString().isEmpty();
          if (executionCommand.resultData.exitCode != 0 || stderrSet) {
              Logger.logErrorExtended(LOG_TAG, executionCommand.toString());
              if (stderrSet)
                  statOutput.append("\n").append(executionCommand.resultData.stderr.toString());
              statOutput.append("\n").append("exit code: ").append(executionCommand.resultData.exitCode.toString());
          }
  
          // Build markdown output
          StringBuilder markdownString = new StringBuilder();
          markdownString.append("## ").append(TermuxConstants.TERMUX_APP_NAME).append(" Files Info\n\n");
          AndroidUtils.appendPropertyToMarkdown(markdownString,"TERMUX_REQUIRED_FILES_DIR_PATH ($PREFIX)", TermuxConstants.TERMUX_FILES_DIR_PATH);
          AndroidUtils.appendPropertyToMarkdown(markdownString,"ANDROID_ASSIGNED_FILES_DIR_PATH", filesDir);
          markdownString.append("\n\n").append(MarkdownUtils.getMarkdownCodeForString(statOutput.toString(), true));
          markdownString.append("\n##\n");
  
          return markdownString.toString();
      }
  
  }
  