# Copyright 2017, The Android Open Source Project
#
# Licensed 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.

"""Utility functions for atest."""


# pylint: disable=import-outside-toplevel
# pylint: disable=too-many-lines

from __future__ import print_function

from dataclasses import dataclass
import datetime
import enum
import fnmatch
import hashlib
import html
import importlib
import itertools
import json
import logging
from multiprocessing import Process
import os
from pathlib import Path
import pickle
import platform
import re
import shutil
import subprocess
import sys
from threading import Thread
import traceback
from typing import Any, Dict, List, Set, Tuple
import urllib
import xml.etree.ElementTree as ET
import zipfile

from atest import atest_decorator
from atest import constants
from atest.atest_enum import DetectType, ExitCode, FilterType
from atest.metrics import metrics
from atest.metrics import metrics_utils
from atest.tf_proto import test_record_pb2

_BASH_RESET_CODE = '\033[0m\n'
DIST_OUT_DIR = Path(
    os.environ.get(constants.ANDROID_BUILD_TOP, os.getcwd()) + '/out/dist/'
)
MAINLINE_MODULES_EXT_RE = re.compile(r'\.(apex|apks|apk)$')
TEST_WITH_MAINLINE_MODULES_RE = re.compile(
    r'(?P<test>.*)\[(?P<mainline_modules>.*' r'[.](apk|apks|apex))\]$'
)

# Arbitrary number to limit stdout for failed runs in run_limited_output.
# Reason for its use is that the make command itself has its own carriage
# return output mechanism that when collected line by line causes the streaming
# full_output list to be extremely large.
_FAILED_OUTPUT_LINE_LIMIT = 100
# Regular expression to match the start of a ninja compile:
# ex: [ 99% 39710/39711]
_BUILD_COMPILE_STATUS = re.compile(r'\[\s*(\d{1,3}%\s+)?\d+/\d+\]')
_BUILD_FAILURE = 'FAILED: '
BUILD_TOP_HASH = hashlib.md5(
    os.environ.get(constants.ANDROID_BUILD_TOP, '').encode()
).hexdigest()
_DEFAULT_TERMINAL_WIDTH = 80
_DEFAULT_TERMINAL_HEIGHT = 25
_BUILD_CMD = 'build/soong/soong_ui.bash'
_FIND_MODIFIED_FILES_CMDS = (
    'cd {};'
    'local_branch=$(git rev-parse --abbrev-ref HEAD);'
    "remote_branch=$(git branch -r | grep '\\->' | awk '{{print $1}}');"
    # Get the number of commits from local branch to remote branch.
    'ahead=$(git rev-list --left-right --count $local_branch...$remote_branch '
    "| awk '{{print $1}}');"
    # Get the list of modified files from HEAD to previous $ahead generation.
    'git diff HEAD~$ahead --name-only'
)
_ANDROID_BUILD_EXT = ('.bp', '.mk')

# Set of special chars for various purposes.
_REGEX_CHARS = {'[', '(', '{', '|', '\\', '*', '?', '+', '^'}
_WILDCARD_CHARS = {'?', '*'}

_WILDCARD_FILTER_RE = re.compile(r'.*[?|*]$')
_REGULAR_FILTER_RE = re.compile(r'.*\w$')
# Printed before the html log line. May be used in tests to parse the html path.
_HTML_LOG_PRINT_PREFIX = 'To access logs, press "ctrl" and click on'

SUGGESTIONS = {
    # (b/177626045) If Atest does not install target application properly.
    'Runner reported an invalid method': 'Please reflash the device(s).',
}

_BUILD_ENV = {}

CACHE_VERSION = 1

_original_sys_stdout = sys.stdout


@dataclass
class BuildEnvProfiler:
  """Represents the condition before and after trigging build."""

  ninja_file: Path
  ninja_file_mtime: float
  variable_file: Path
  variable_file_md5: str
  clean_out: bool
  build_files_integrity: bool


@enum.unique
class BuildOutputMode(enum.Enum):
  'Represents the different ways to display build output.'

  STREAMED = 'streamed'
  LOGGED = 'logged'

  def __init__(self, arg_name: str):
    self._description = arg_name

  # pylint: disable=missing-function-docstring
  def description(self):
    return self._description


@dataclass
class AndroidVariables:
  """Class that stores the value of environment variables."""

  build_top: str
  product_out: str
  target_out_cases: str
  host_out: str
  host_out_cases: str
  target_product: str
  build_variant: str

  def __init__(self):
    self.build_top = os.getenv('ANDROID_BUILD_TOP')
    self.product_out = os.getenv('ANDROID_PRODUCT_OUT')
    self.target_out_cases = os.getenv('ANDROID_TARGET_OUT_TESTCASES')
    self.host_out = os.getenv('ANDROID_HOST_OUT')
    self.host_out_cases = os.getenv('ANDROID_HOST_OUT_TESTCASES')
    self.target_product = os.getenv('TARGET_PRODUCT')
    self.build_variant = os.getenv('TARGET_BUILD_VARIANT')


def get_build_top(*joinpaths: Any) -> Path:
  """Get the absolute path from the given repo path."""
  return Path(AndroidVariables().build_top, *joinpaths)


def get_host_out(*joinpaths: Any) -> Path:
  """Get the absolute host out path from the given path."""
  return Path(AndroidVariables().host_out, *joinpaths)


def get_product_out(*joinpaths: Any) -> Path:
  """Get the absolute product out path from the given path."""
  return Path(AndroidVariables().product_out, *joinpaths)


def get_index_path(*filename: Any) -> Path:
  """Get absolute path of the desired index file."""
  return get_host_out('indices', *filename)


def getenv_abs_path(env: str, suffix: str = None) -> Path:
  """Translate the environment variable to an absolute path.

  Args:
      env: string of the given environment variable.
      suffix: string that will be appended to.

  Returns:
      Absolute Path of the given environment variable.
  """
  env_value = os.getenv(env)
  if not env_value:
    return None

  env_path = Path(env_value)
  if env_path.is_absolute():
    return env_path.joinpath(suffix) if suffix else env_path

  return get_build_top(env_path, suffix) if suffix else get_build_top(env_path)


def get_build_cmd(dump=False):
  """Compose build command with no-absolute path and flag "--make-mode".

  Args:
      dump: boolean that determines the option of build/soong/soong_iu.bash.
            True: used to dump build variables, equivalent to printconfig. e.g.
              build/soong/soong_iu.bash --dumpvar-mode <VAR_NAME>
            False: (default) used to build targets in make mode. e.g.
              build/soong/soong_iu.bash --make-mode <MOD_NAME>

  Returns:
      A list of soong build command.
  """
  make_cmd = '%s/%s' % (
      os.path.relpath(
          os.environ.get(constants.ANDROID_BUILD_TOP, os.getcwd()), os.getcwd()
      ),
      _BUILD_CMD,
  )
  if dump:
    return [make_cmd, '--dumpvar-mode', 'report_config']
  return [make_cmd, '--make-mode', 'WRAPPER_TOOL=atest']


def _capture_fail_section(full_log):
  """Return the error message from the build output.

  Args:
      full_log: List of strings representing full output of build.

  Returns:
      capture_output: List of strings that are build errors.
  """
  am_capturing = False
  capture_output = []
  for line in full_log:
    if am_capturing and _BUILD_COMPILE_STATUS.match(line):
      break
    if am_capturing or line.startswith(_BUILD_FAILURE):
      capture_output.append(line)
      am_capturing = True
      continue
  return capture_output


def _capture_limited_output(full_log):
  """Return the limited error message from capture_failed_section.

  Args:
      full_log: List of strings representing full output of build.

  Returns:
      output: List of strings that are build errors.
  """
  # Parse out the build error to output.
  output = _capture_fail_section(full_log)
  if not output:
    output = full_log
  if len(output) >= _FAILED_OUTPUT_LINE_LIMIT:
    output = output[-_FAILED_OUTPUT_LINE_LIMIT:]
  output = 'Output (may be trimmed):\n%s' % ''.join(output)
  return output


# TODO: b/187122993 refine subprocess with 'with-statement' in fixit week.
def run_limited_output(cmd, env_vars=None):
  """Runs a given command and streams the output on a single line in stdout.

  Args:
      cmd: A list of strings representing the command to run.
      env_vars: Optional arg. Dict of env vars to set during build.

  Raises:
      subprocess.CalledProcessError: When the command exits with a non-0
          exitcode.
  """
  # Send stderr to stdout so we only have to deal with a single pipe.
  with subprocess.Popen(
      cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, env=env_vars
  ) as proc:
    sys.stdout.write('\n')
    term_width, _ = get_terminal_size()
    white_space = ' ' * int(term_width)
    full_output = []
    while proc.poll() is None:
      line = proc.stdout.readline().decode('utf-8')
      # Readline will often return empty strings.
      if not line:
        continue
      full_output.append(line)
      # Trim the line to the width of the terminal.
      # Note: Does not handle terminal resizing, which is probably not
      #       worth checking the width every loop.
      if len(line) >= term_width:
        line = line[: term_width - 1]
      # Clear the last line we outputted.
      sys.stdout.write('\r%s\r' % white_space)
      sys.stdout.write('%s' % line.strip())
      sys.stdout.flush()
    # Reset stdout (on bash) to remove any custom formatting and newline.
    sys.stdout.write(_BASH_RESET_CODE)
    sys.stdout.flush()
    # Wait for the Popen to finish completely before checking the
    # returncode.
    proc.wait()
    if proc.returncode != 0:
      raise subprocess.CalledProcessError(proc.returncode, cmd, full_output)


def get_build_out_dir(*joinpaths) -> Path:
  """Get android build out directory.

  The order of the rules are:
  1. OUT_DIR
  2. OUT_DIR_COMMON_BASE
  3. ANDROID_BUILD_TOP/out

  e.g. OUT_DIR='/disk1/out' -> '/disk1/out'
       OUT_DIR='out_dir'    -> '<build_top>/out_dir'

       Assume the branch name is 'aosp-main':
       OUT_DIR_COMMON_BASE='/disk2/out' -> '/disk1/out/aosp-main'
       OUT_DIR_COMMON_BASE='out_dir'    -> '<build_top>/out_dir/aosp-main'

  Returns:
      Absolute Path of the out directory.
  """
  out_dir = getenv_abs_path('OUT_DIR')
  if out_dir:
    return out_dir.joinpath(*joinpaths)

  # https://source.android.com/setup/build/initializing#using-a-separate-output-directory
  basename = get_build_top().name
  out_dir_common_base = getenv_abs_path('OUT_DIR_COMMON_BASE', basename)
  if out_dir_common_base:
    return out_dir_common_base.joinpath(*joinpaths)

  return get_build_top('out').joinpath(*joinpaths)


def update_build_env(env: Dict[str, str]):
  """Method that updates build environment variables."""
  # pylint: disable=global-statement, global-variable-not-assigned
  global _BUILD_ENV
  _BUILD_ENV.update(env)


def build(build_targets: Set[str]):
  """Shell out and invoke run_build_cmd to make build_targets.

  Args:
      build_targets: A set of strings of build targets to make.

  Returns:
      Boolean of whether build command was successful, True if nothing to
      build.
  """
  if not build_targets:
    logging.debug('No build targets, skipping build.')
    return True

  # pylint: disable=global-statement, global-variable-not-assigned
  global _BUILD_ENV
  full_env_vars = os.environ.copy()
  update_build_env(full_env_vars)
  print(
      '\n%s\n%s'
      % (mark_cyan('Building Dependencies...'), ', '.join(build_targets))
  )
  logging.debug('Building Dependencies: %s', ' '.join(build_targets))
  cmd = get_build_cmd() + list(build_targets)
  return _run_build_cmd(cmd, _BUILD_ENV)


def _run_build_cmd_with_limited_output(
    cmd: List[str], env_vars: Dict[str, str] = None
) -> None:
  """Runs the build command and streams the output on a single line in stdout.

  Args:
      cmd: A list of strings representing the command to run.
      env_vars: Optional arg. Dict of env vars to set during build.

  Raises:
      subprocess.CalledProcessError: When the command exits with a non-0
          exitcode.
  """
  try:
    run_limited_output(cmd, env_vars=env_vars)
  except subprocess.CalledProcessError as e:
    # get error log from "OUT_DIR/error.log"
    error_log_file = get_build_out_dir('error.log')
    output = []
    if error_log_file.is_file():
      if error_log_file.stat().st_size > 0:
        with open(error_log_file, encoding='utf-8') as f:
          output = f.read()
    if not output:
      output = _capture_limited_output(e.output)
    raise subprocess.CalledProcessError(e.returncode, e.cmd, output)


def _run_build_cmd(cmd: List[str], env_vars: Dict[str, str]):
  """The main process of building targets.

  Args:
      cmd: A list of soong command.
      env_vars: Dict of environment variables used for build.

  Returns:
      Boolean of whether build command was successful, True if nothing to
      build.
  """
  logging.debug('Executing command: %s', cmd)
  build_profiler = _build_env_profiling()
  try:
    if env_vars.get('BUILD_OUTPUT_MODE') == BuildOutputMode.STREAMED.value:
      print()
      subprocess.check_call(cmd, stderr=subprocess.STDOUT, env=env_vars)
    else:
      # Note that piping stdout forces Soong to switch to 'dumb terminal
      # mode' which only prints completed actions. This gives users the
      # impression that actions are taking longer than they really are.
      # See b/233044822 for more details.
      log_path = get_build_out_dir('verbose.log.gz')
      print(
          '\n(Build log may not reflect actual status in simple output'
          'mode; check {} for detail after build finishes.)'.format(
              mark_cyan(f'{log_path}')
          ),
          end='',
      )
      _run_build_cmd_with_limited_output(cmd, env_vars=env_vars)
    _send_build_condition_metrics(build_profiler, cmd)
    print_and_log_info('Build successful')
    return True
  except subprocess.CalledProcessError as err:
    print_and_log_error('Build failure when running: %s', ' '.join(cmd))
    if err.output:
      print_and_log_error(err.output)
    return False


# pylint: disable=unused-argument
def get_result_server_args(for_test_mapping=False):
  """Return list of args for communication with result server.

  Args:
      for_test_mapping: True if the test run is for Test Mapping to include
        additional reporting args. Default is False.
  """
  # Customize test mapping argument here if needed.
  return constants.RESULT_SERVER_ARGS


def sort_and_group(iterable, key):
  """Sort and group helper function."""
  return itertools.groupby(sorted(iterable, key=key), key=key)


def is_supported_mainline_module(installed_path: str) -> re.Match:
  """Determine whether the given path is supported."""
  return re.search(MAINLINE_MODULES_EXT_RE, installed_path)


def get_test_and_mainline_modules(test_name: str) -> re.Match:
  """Return test name and mainline modules from the given test."""
  return TEST_WITH_MAINLINE_MODULES_RE.match(test_name)


def is_test_mapping(args):
  """Check if the atest command intends to run tests in test mapping.

  When atest runs tests in test mapping, it must have at most one test
  specified. If a test is specified, it must be started with  `:`,
  which means the test value is a test group name in TEST_MAPPING file, e.g.,
  `:postsubmit`.

  If --host-unit-test-only or --smart-testing-local was applied, it doesn't
  intend to be a test_mapping test.
  If any test mapping options is specified, the atest command must also be
  set to run tests in test mapping files.

  Args:
      args: arg parsed object.

  Returns:
      True if the args indicates atest shall run tests in test mapping. False
      otherwise.
  """
  if args.host_unit_test_only:
    return False
  if any((args.test_mapping, args.include_subdirs, not args.tests)):
    return True
  # ':postsubmit' implicitly indicates running in test-mapping mode.
  return all((len(args.tests) == 1, args.tests[0][0] == ':'))


@atest_decorator.static_var('cached_has_colors', {})
def _has_colors(stream):
  """Check the output stream is colorful.

  Args:
      stream: The standard file stream.

  Returns:
      True if the file stream can interpreter the ANSI color code.
  """
  cached_has_colors = _has_colors.cached_has_colors
  if stream in cached_has_colors:
    return cached_has_colors[stream]
  cached_has_colors[stream] = True
  # Following from Python cookbook, #475186
  if not hasattr(stream, 'isatty'):
    cached_has_colors[stream] = False
    return False
  if not stream.isatty():
    # Auto color only on TTYs
    cached_has_colors[stream] = False
    return False
  # curses.tigetnum() cannot be used for telling supported color numbers
  # because it does not come with the prebuilt py3-cmd.
  return cached_has_colors[stream]


def colorize(text, color, bp_color=None):
  """Convert to colorful string with ANSI escape code.

  Args:
      text: A string to print.
      color: Forground(Text) color which is an ANSI code shift for colorful
        print. They are defined in constants_default.py.
      bp_color: Backgroud color which is an ANSI code shift for colorful print.

  Returns:
      Colorful string with ANSI escape code.
  """
  clr_pref = '\033[1;'
  clr_suff = '\033[0m'
  has_colors = _has_colors(_original_sys_stdout)
  if has_colors:
    background_color = ''
    if bp_color:
      # Foreground(Text) ranges from 30-37
      text_color = 30 + color
      # Background ranges from 40-47
      background_color = ';%d' % (40 + bp_color)
    else:
      text_color = 30 + color
    clr_str = '%s%d%sm%s%s' % (
        clr_pref,
        text_color,
        background_color,
        text,
        clr_suff,
    )
  else:
    clr_str = text
  return clr_str


def mark_red(text):
  """Wrap colorized function and print in red."""
  return colorize(text, constants.RED)


def mark_yellow(text):
  """Wrap colorized function and print in yellow."""
  return colorize(text, constants.YELLOW)


def mark_green(text):
  """Wrap colorized function and print in green."""
  return colorize(text, constants.GREEN)


def mark_magenta(text):
  """Wrap colorized function and print in magenta."""
  return colorize(text, constants.MAGENTA)


def mark_cyan(text):
  """Wrap colorized function and print in cyan."""
  return colorize(text, constants.CYAN)


def mark_blue(text):
  """Wrap colorized function and print in blue."""
  return colorize(text, constants.BLUE)


def colorful_print(text, color, bp_color=None, auto_wrap=True):
  """Print out the text with color.

  Args:
      text: A string to print.
      color: Forground(Text) color which is an ANSI code shift for colorful
        print. They are defined in constants_default.py.
      bp_color: Backgroud color which is an ANSI code shift for colorful print.
      auto_wrap: If True, Text wraps while print.
  """
  output = colorize(text, color, bp_color)
  if auto_wrap:
    print(output)
  else:
    print(output, end='')


def _print_to_console(
    prefix: str, color: int, msg: Any, *fmt_args: list[Any]
) -> None:
  """Print a message to the console.

  Args:
    msg: The message to format.
    *fmt_args: Format arguments for the message.
  """
  if not fmt_args:
    evaluated_msg = str(msg)
  else:
    try:
      evaluated_msg = msg % fmt_args
    except (TypeError, ValueError):
      traceback.print_exc()
      return
  colorful_print(f'{prefix}{evaluated_msg}', color)


def print_and_log_error(msg, *fmt_args):
  """Print error message to the console and log it.

  Args:
    msg: The message to print.
    *fmt_args: Format arguments for the message.
  """
  logging.error(msg, *fmt_args)
  _print_to_console('Error: ', constants.RED, msg, *fmt_args)


def print_and_log_warning(msg, *fmt_args):
  """Print warning message to the console and log it.

  Args:
    msg: The message to print.
    *fmt_args: Format arguments for the message.
  """
  logging.warning(msg, *fmt_args)
  _print_to_console('Warning: ', constants.YELLOW, msg, *fmt_args)


def print_and_log_info(msg, *fmt_args):
  """Print info message to the console and log it.

  Args:
    msg: The message to print.
    *fmt_args: Format arguments for the message.
  """
  logging.info(msg, *fmt_args)
  _print_to_console('Info: ', constants.WHITE, msg, *fmt_args)


def get_terminal_size():
  """Get terminal size and return a tuple.

  Returns:
      2 integers: the size of X(columns) and Y(lines/rows).
  """
  # Determine the width of the terminal. We'll need to clear this many
  # characters when carriage returning. Set default value as 80.
  columns, rows = shutil.get_terminal_size(
      fallback=(_DEFAULT_TERMINAL_WIDTH, _DEFAULT_TERMINAL_HEIGHT)
  )
  return columns, rows


def _get_hashed_file_name(main_file_name):
  """Convert the input string to a md5-hashed string.

  If file_extension is

     given, returns $(hashed_string).$(file_extension), otherwise
     $(hashed_string).cache.

  Args:
      main_file_name: The input string need to be hashed.

  Returns:
      A string as hashed file name with .cache file extension.
  """
  hashed_fn = hashlib.md5(str(main_file_name).encode())
  hashed_name = hashed_fn.hexdigest()
  return hashed_name + '.cache'


def md5sum(filename):
  """Generate MD5 checksum of a file.

  Args:
      name: A string of a filename.

  Returns:
      A string of hashed MD5 checksum.
  """
  filename = Path(filename)
  if not filename.is_file():
    return ''
  with open(filename, 'rb') as target:
    content = target.read()
  if not isinstance(content, bytes):
    content = content.encode('utf-8')
  return hashlib.md5(content).hexdigest()


def check_md5(check_file, missing_ok=False):
  """Method equivalent to 'md5sum --check /file/to/check'.

  Args:
      check_file: A string of filename that stores filename and its md5
        checksum.
      missing_ok: A boolean that considers OK even when the check_file does not
        exist. Using missing_ok=True allows ignoring md5 check especially for
        initial run that the check_file has not yet generated. Using
        missing_ok=False ensures the consistency of files, and guarantees the
        process is successfully completed.

  Returns:
      When missing_ok is True (soft check):
        - True if the checksum is consistent with the actual MD5, even the
          check_file is missing or not a valid JSON.
        - False when the checksum is inconsistent with the actual MD5.
      When missing_ok is False (ensure the process completed properly):
        - True if the checksum is consistent with the actual MD5.
        - False otherwise.
  """
  if not Path(check_file).is_file():
    if not missing_ok:
      logging.debug('Unable to verify: %s not found.', check_file)
    return missing_ok
  content = load_json_safely(check_file)
  if content:
    for filename, md5 in content.items():
      if md5sum(filename) != md5:
        logging.debug('%s has altered.', filename)
        return False
    return True
  return False


def save_md5(filenames, save_file):
  """Method equivalent to 'md5sum file1 file2 > /file/to/check'

  Args:
      filenames: A list of filenames.
      save_file: Filename for storing files and their md5 checksums.
  """
  data = {}
  for f in filenames:
    name = Path(f)
    if not name.is_file():
      print_and_log_warning(' ignore %s: not a file.', name)
    data.update({str(name): md5sum(name)})
  with open(save_file, 'w+', encoding='utf-8') as _file:
    json.dump(data, _file)


def get_cache_root():
  """Get the root path dir for cache.

  Use branch and target information as cache_root.
  The path will look like:
     $(ANDROID_PRODUCT_OUT)/atest_cache/$CACHE_VERSION

  Returns:
      A string of the path of the root dir of cache.
  """
  # Note that the cache directory is stored in the build output directory. We
  # do this because this directory is periodically cleaned and don't have to
  # worry about the files growing without bound. The files are also much
  # smaller than typical build output and less of an issue. Use build out to
  # save caches which is next to atest_bazel_workspace which is easy for user
  # to manually clean up if need. Use product out folder's base name as part
  # of directory because of there may be different module-info in the same
  # branch but different lunch target.
  return os.path.join(
      get_build_out_dir(),
      'atest_cache',
      f'ver_{CACHE_VERSION}',
      os.path.basename(
          os.environ.get(
              constants.ANDROID_PRODUCT_OUT, constants.ANDROID_PRODUCT_OUT
          )
      ),
  )


def get_test_info_cache_path(test_reference, cache_root=None):
  """Get the cache path of the desired test_infos.

  Args:
      test_reference: A string of the test.
      cache_root: Folder path where stores caches.

  Returns:
      A string of the path of test_info cache.
  """
  if not cache_root:
    cache_root = get_cache_root()
  return os.path.join(cache_root, _get_hashed_file_name(test_reference))


def update_test_info_cache(test_reference, test_infos, cache_root=None):
  """Update cache content which stores a set of test_info objects through

     pickle module, each test_reference will be saved as a cache file.

  Args:
      test_reference: A string referencing a test.
      test_infos: A set of TestInfos.
      cache_root: Folder path for saving caches.
  """
  if not cache_root:
    cache_root = get_cache_root()
  if not os.path.isdir(cache_root):
    os.makedirs(cache_root)
  cache_path = get_test_info_cache_path(test_reference, cache_root)
  # Save test_info to files.
  try:
    with open(cache_path, 'wb') as test_info_cache_file:
      logging.debug('Saving cache %s.', cache_path)
      pickle.dump(test_infos, test_info_cache_file, protocol=2)
  except (pickle.PicklingError, TypeError, IOError) as err:
    # Won't break anything, just log this error, and collect the exception
    # by metrics.
    logging.debug('Exception raised: %s', err)
    metrics_utils.handle_exc_and_send_exit_event(constants.ACCESS_CACHE_FAILURE)


def load_test_info_cache(test_reference, cache_root=None):
  """Load cache by test_reference to a set of test_infos object.

  Args:
      test_reference: A string referencing a test.
      cache_root: Folder path for finding caches.

  Returns:
      A list of TestInfo namedtuple if cache found, else None.
  """
  if not cache_root:
    cache_root = get_cache_root()

  cache_file = get_test_info_cache_path(test_reference, cache_root)
  if os.path.isfile(cache_file):
    logging.debug('Loading cache %s.', cache_file)
    try:
      with open(cache_file, 'rb') as config_dictionary_file:
        return pickle.load(config_dictionary_file, encoding='utf-8')
    except (
        pickle.UnpicklingError,
        ValueError,
        TypeError,
        EOFError,
        IOError,
        ImportError,
    ) as err:
      # Won't break anything, just remove the old cache, log this error,
      # and collect the exception by metrics.
      logging.debug('Exception raised: %s', err)
      os.remove(cache_file)
      metrics_utils.handle_exc_and_send_exit_event(
          constants.ACCESS_CACHE_FAILURE
      )
  return None


def clean_test_info_caches(tests, cache_root=None):
  """Clean caches of input tests.

  Args:
      tests: A list of test references.
      cache_root: Folder path for finding caches.
  """
  if not cache_root:
    cache_root = get_cache_root()
  for test in tests:
    cache_file = get_test_info_cache_path(test, cache_root)
    if os.path.isfile(cache_file):
      logging.debug('Removing cache: %s', cache_file)
      try:
        os.remove(cache_file)
      except IOError as err:
        logging.debug('Exception raised: %s', err)
        metrics_utils.handle_exc_and_send_exit_event(
            constants.ACCESS_CACHE_FAILURE
        )


def get_modified_files(root_dir):
  """Get the git modified files.

  The git path here is git top level of the root_dir. It's inevitable to utilise
  different commands to fulfill 2 scenario:

      1. locate unstaged/staged files
      2. locate committed files but not yet merged.
  the 'git_status_cmd' fulfils the former while the 'find_modified_files'
  fulfils the latter.

  Args:
      root_dir: the root where it starts finding.

  Returns:
      A set of modified files altered since last commit.
  """
  modified_files = set()
  try:
    # TODO: (@jimtang) abandon using git command within Atest.
    find_git_cmd = f'cd {root_dir}; git rev-parse --show-toplevel 2>/dev/null'
    git_paths = (
        subprocess.check_output(find_git_cmd, shell=True).decode().splitlines()
    )
    for git_path in git_paths:
      # Find modified files from git working tree status.
      git_status_cmd = (
          "repo forall {} -c git status --short | awk '{{print $NF}}'"
      ).format(git_path)
      modified_wo_commit = (
          subprocess.check_output(git_status_cmd, shell=True)
          .decode()
          .rstrip()
          .splitlines()
      )
      for change in modified_wo_commit:
        modified_files.add(os.path.normpath('{}/{}'.format(git_path, change)))
      # Find modified files that are committed but not yet merged.
      find_modified_files = _FIND_MODIFIED_FILES_CMDS.format(git_path)
      commit_modified_files = (
          subprocess.check_output(find_modified_files, shell=True)
          .decode()
          .splitlines()
      )
      for line in commit_modified_files:
        modified_files.add(os.path.normpath('{}/{}'.format(git_path, line)))
  except (OSError, subprocess.CalledProcessError) as err:
    logging.debug('Exception raised: %s', err)
  return modified_files


def delimiter(char, length=_DEFAULT_TERMINAL_WIDTH, prenl=0, postnl=0):
  """A handy delimiter printer.

  Args:
      char: A string used for delimiter.
      length: An integer for the replication.
      prenl: An integer that insert '\n' before delimiter.
      postnl: An integer that insert '\n' after delimiter.

  Returns:
      A string of delimiter.
  """
  return prenl * '\n' + char * length + postnl * '\n'


def find_files(path, file_name=constants.TEST_MAPPING, followlinks=False):
  """Find all files with given name under the given path.

  Args:
      path: A string of path in source.
      file_name: The file name pattern for finding matched files.
      followlinks: A boolean to indicate whether to follow symbolic links.

  Returns:
      A list of paths of the files with the matching name under the given
      path.
  """
  match_files = []
  for root, _, filenames in os.walk(path, followlinks=followlinks):
    try:
      for filename in fnmatch.filter(filenames, file_name):
        match_files.append(os.path.join(root, filename))
    except re.error as e:
      msg = 'Unable to locate %s among %s' % (file_name, filenames)
      logging.debug(msg)
      logging.debug('Exception: %s', e)
      metrics.AtestExitEvent(
          duration=metrics_utils.convert_duration(0),
          exit_code=ExitCode.COLLECT_ONLY_FILE_NOT_FOUND,
          stacktrace=msg,
          logs=str(e),
      )
  return match_files


def extract_zip_text(zip_path):
  """Extract the text files content for input zip file.

  Args:
      zip_path: The file path of zip.

  Returns:
      The string in input zip file.
  """
  content = ''
  try:
    with zipfile.ZipFile(zip_path) as zip_file:
      for filename in zip_file.namelist():
        if os.path.isdir(filename):
          continue
        # Force change line if multiple text files in zip
        content = content + '\n'
        # read the file
        with zip_file.open(filename) as extract_file:
          for line in extract_file:
            if matched_tf_error_log(line.decode()):
              content = content + line.decode()
  except zipfile.BadZipfile as err:
    logging.debug('Exception raised: %s', err)
  return content


def matched_tf_error_log(content):
  """Check if the input content matched tradefed log pattern.

  The format will look like this. 05-25 17:37:04 W/XXXXXX 05-25 17:37:04
  E/XXXXXX

  Args:
      content: Log string.

  Returns:
      True if the content matches the regular expression for tradefed error or
      warning log.
  """
  reg = (
      '^((0[1-9])|(1[0-2]))-((0[1-9])|([12][0-9])|(3[0-1])) '
      '(([0-1][0-9])|([2][0-3])):([0-5][0-9]):([0-5][0-9]) (E|W/)'
  )
  if re.search(reg, content):
    return True
  return False


def read_test_record(path):
  """A Helper to read test record proto.

  Args:
      path: The proto file path.

  Returns:
      The test_record proto instance.
  """
  with open(path, 'rb') as proto_file:
    msg = test_record_pb2.TestRecord()
    msg.ParseFromString(proto_file.read())
  return msg


def has_python_module(module_name):
  """Detect if the module can be loaded without importing it in real.

  Args:
      cmd: A string of the tested module name.

  Returns:
      True if found, False otherwise.
  """
  return bool(importlib.util.find_spec(module_name))


def load_json_safely(jsonfile):
  """Load the given json file as an object.

  Args:
      jsonfile: The json file path.

  Returns:
      The content of the give json file. Null dict when:
      1. the given path doesn't exist.
      2. the given path is not a json or invalid format.
  """
  if isinstance(jsonfile, bytes):
    jsonfile = jsonfile.decode('utf-8')
  if Path(jsonfile).is_file():
    try:
      with open(jsonfile, 'r', encoding='utf-8') as cache:
        return json.load(cache)
    except json.JSONDecodeError:
      logging.debug('Exception happened while loading %s.', jsonfile)
  else:
    logging.debug('%s: File not found.', jsonfile)
  return {}


def get_atest_version():
  """Get atest version.

  Returns:
      Version string from the VERSION file, e.g. prebuilt
          2022-11-24_9314547  (<release_date>_<build_id>)

      If VERSION does not exist (src or local built):
          2022-11-24_5d448c50 (<commit_date>_<commit_id>)

      If the git command fails for unexpected reason:
          2022-11-24_unknown  (<today_date>_unknown)
  """
  try:
    with importlib.resources.as_file(
        importlib.resources.files('atest').joinpath('VERSION')
    ) as version_file_path:
      return version_file_path.read_text(encoding='utf-8')
  except (ModuleNotFoundError, FileNotFoundError):
    logging.debug(
        'Failed to load package resource atest/VERSION, possibly due to running'
        ' from atest-dev, atest-src, a prebuilt without embedded launcher, or a'
        ' prebuilt not created by the asuite release tool. Falling back to'
        ' legacy source search.'
    )
    version_file = Path(__file__).resolve().parent.joinpath('VERSION')
    if Path(version_file).is_file():
      return open(version_file, encoding='utf-8').read()

  # Try fetching commit date (%ci) and commit hash (%h).
  git_cmd = 'git log -1 --pretty=format:"%ci;%h"'
  try:
    # commit date/hash are only available when running from the source
    # and the local built.
    result = subprocess.run(
        git_cmd,
        shell=True,
        check=False,
        capture_output=True,
        cwd=Path(os.getenv(constants.ANDROID_BUILD_TOP), '').joinpath(
            'tools/asuite/atest'
        ),
    )
    if result.stderr:
      raise subprocess.CalledProcessError(returncode=0, cmd=git_cmd)
    raw_date, commit = result.stdout.decode().split(';')
    date = datetime.datetime.strptime(raw_date, '%Y-%m-%d %H:%M:%S %z').date()
  # atest_dir doesn't exist will throw FileNotFoundError.
  except (subprocess.CalledProcessError, FileNotFoundError):
    # Use today as the commit date for unexpected conditions.
    date = datetime.datetime.today().date()
    commit = 'unknown'
  return f'{date}_{commit}'


def get_manifest_branch(show_aosp=False):
  """Get the manifest branch.

  Args:
      show_aosp: A boolean that shows 'aosp' prefix by checking the 'remote'
        attribute.

  Returns:
      The value of 'revision' of the included xml or default.xml.

      None when no ANDROID_BUILD_TOP or unable to access default.xml.
  """
  #      (portal xml)                            (default xml)
  # +--------------------+ _get_include() +-----------------------------+
  # | .repo/manifest.xml |--------------->| .repo/manifests/default.xml |
  # +--------------------+                +---------------+-------------+
  #                          <default revision="master" |
  #                                   remote="aosp"     | _get_revision()
  #                                   sync-j="4"/>      V
  #                                                 +--------+
  #                                                 | master |
  #                                                 +--------+
  build_top = os.getenv(constants.ANDROID_BUILD_TOP)
  if not build_top:
    return None
  portal_xml = Path(build_top).joinpath('.repo', 'manifest.xml')
  default_xml = Path(build_top).joinpath('.repo/manifests', 'default.xml')

  def _get_revision(xml):
    try:
      xml_root = ET.parse(xml).getroot()
    except (IOError, OSError, ET.ParseError):
      # TODO(b/274989179) Change back to warning once warning if not going
      # to be treat as test failure. Or test_get_manifest_branch unit test
      # could be fix if return None if portal_xml or default_xml not
      # exist.
      logging.info('%s could not be read.', xml)
      return ''
    default_tags = xml_root.findall('./default')
    if default_tags:
      prefix = ''
      for tag in default_tags:
        branch = tag.attrib.get('revision')
        if show_aosp and tag.attrib.get('remote') == 'aosp':
          prefix = 'aosp-'
        return f'{prefix}{branch}'
    return ''

  def _get_include(xml):
    try:
      xml_root = ET.parse(xml).getroot()
    except (IOError, OSError, ET.ParseError):
      # TODO(b/274989179) Change back to warning once warning if not going
      # to be treat as test failure. Or test_get_manifest_branch unit test
      # could be fix if return None if portal_xml or default_xml not
      # exist.
      logging.info('%s could not be read.', xml)
      return Path()
    include_tags = xml_root.findall('./include')
    if include_tags:
      for tag in include_tags:
        name = tag.attrib.get('name')
        if name:
          return Path(build_top).joinpath('.repo/manifests', name)
    return default_xml

  # 1. Try getting revision from .repo/manifests/default.xml
  if default_xml.is_file():
    return _get_revision(default_xml)
  # 2. Try getting revision from the included xml of .repo/manifest.xml
  include_xml = _get_include(portal_xml)
  if include_xml.is_file():
    return _get_revision(include_xml)
  # 3. Try getting revision directly from manifest.xml (unlikely to happen)
  return _get_revision(portal_xml)


def get_build_target():
  """Get the build target form system environment TARGET_PRODUCT."""
  build_target = '%s-%s-%s' % (
      os.getenv(constants.ANDROID_TARGET_PRODUCT, None),
      os.getenv('TARGET_RELEASE', None),
      os.getenv(constants.TARGET_BUILD_VARIANT, None),
  )
  return build_target


def has_wildcard(test_name):
  """Tell whether the test_name(either a list or string) contains wildcard

  symbols.

  Args:
      test_name: A list or a str.

  Return:
      True if test_name contains wildcard, False otherwise.
  """
  if isinstance(test_name, str):
    return any(char in test_name for char in _WILDCARD_CHARS)
  if isinstance(test_name, list):
    for name in test_name:
      if has_wildcard(name):
        return True
  return False


def is_build_file(path):
  """If input file is one of an android build file.

  Args:
      path: A string of file path.

  Return:
      True if path is android build file, False otherwise.
  """
  return bool(os.path.splitext(path)[-1] in _ANDROID_BUILD_EXT)


def quote(input_str):
  """If the input string -- especially in custom args -- contains shell-aware

  characters, insert a pair of "\" to the input string.

  e.g. unit(test|testing|testing) -> 'unit(test|testing|testing)'

  Args:
      input_str: A string from user input.

  Returns: A string with single quotes if regex chars were detected.
  """
  if has_chars(input_str, _REGEX_CHARS):
    return "'" + input_str + "'"
  return input_str


def has_chars(input_str, chars):
  """Check if the input string contains one of the designated characters.

  Args:
      input_str: A string from user input.
      chars: An iterable object.

  Returns:
      True if the input string contains one of the special chars.
  """
  for char in chars:
    if char in input_str:
      return True
  return False


def prompt_with_yn_result(msg, default=True):
  """Prompt message and get yes or no result.

  Args:
      msg: The question you want asking.
      default: boolean to True/Yes or False/No

  Returns:
      default value if get KeyboardInterrupt or ValueError exception.
  """
  suffix = '[Y/n]: ' if default else '[y/N]: '
  try:
    return strtobool(input(msg + suffix))
  except (ValueError, KeyboardInterrupt):
    return default


def strtobool(val):
  """Convert a string representation of truth to True or False.

  Args:
      val: a string of input value.

  Returns:
      True when values are 'y', 'yes', 't', 'true', 'on', and '1';
      False when 'n', 'no', 'f', 'false', 'off', and '0'.
      Raises ValueError if 'val' is anything else.
  """
  if val.lower() in ('y', 'yes', 't', 'true', 'on', '1'):
    return True
  if val.lower() in ('n', 'no', 'f', 'false', 'off', '0'):
    return False
  raise ValueError('invalid truth value %r' % (val,))


def get_android_junit_config_filters(test_config):
  """Get the dictionary of a input config for junit config's filters

  Args:
      test_config: The path of the test config.

  Returns:
      A dictionary include all the filters in the input config.
  """
  filter_dict = {}
  xml_root = ET.parse(test_config).getroot()
  option_tags = xml_root.findall('.//option')
  for tag in option_tags:
    name = tag.attrib['name'].strip()
    if name in constants.SUPPORTED_FILTERS:
      filter_values = filter_dict.get(name, [])
      value = tag.attrib['value'].strip()
      filter_values.append(value)
      filter_dict.update({name: filter_values})
  return filter_dict


def get_config_parameter(test_config):
  """Get all the parameter values for the input config

  Args:
      test_config: The path of the test config.

  Returns:
      A set include all the parameters of the input config.
  """
  parameters = set()
  xml_root = ET.parse(test_config).getroot()
  option_tags = xml_root.findall('.//option')
  for tag in option_tags:
    name = tag.attrib['name'].strip()
    if name == constants.CONFIG_DESCRIPTOR:
      key = tag.attrib['key'].strip()
      if key == constants.PARAMETER_KEY:
        value = tag.attrib['value'].strip()
        parameters.add(value)
  return parameters


def get_config_device(test_config):
  """Get all the device names from the input config

  Args:
      test_config: The path of the test config.

  Returns:
      A set include all the device name of the input config.
  """
  devices = set()
  try:
    xml_root = ET.parse(test_config).getroot()
    device_tags = xml_root.findall('.//device')
    for tag in device_tags:
      name = tag.attrib['name'].strip()
      devices.add(name)
  except ET.ParseError as e:
    colorful_print('Config has invalid format.', constants.RED)
    colorful_print('File %s : %s' % (test_config, str(e)), constants.YELLOW)
    sys.exit(ExitCode.CONFIG_INVALID_FORMAT)
  return devices


def get_mainline_param(test_config):
  """Get all the mainline-param values for the input config

  Args:
      test_config: The path of the test config.

  Returns:
      A set include all the parameters of the input config.
  """
  mainline_param = set()
  xml_root = ET.parse(test_config).getroot()
  option_tags = xml_root.findall('.//option')
  for tag in option_tags:
    name = tag.attrib['name'].strip()
    if name == constants.CONFIG_DESCRIPTOR:
      key = tag.attrib['key'].strip()
      if key == constants.MAINLINE_PARAM_KEY:
        value = tag.attrib['value'].strip()
        mainline_param.add(value)
  return mainline_param


def get_adb_devices():
  """Run `adb devices` and return a list of devices.

  Returns:
      A list of devices. e.g.
      ['127.0.0.1:40623', '127.0.0.1:40625']
  """
  probe_cmd = 'adb devices | egrep -v "^List|^$"||true'
  suts = subprocess.check_output(probe_cmd, shell=True).decode().splitlines()
  return [sut.split('\t')[0] for sut in suts]


def get_android_config():
  """Get Android config as "printconfig" shows.

  Returns:
      A dict of Android configurations.
  """
  dump_cmd = get_build_cmd(dump=True)
  raw_config = subprocess.check_output(dump_cmd).decode('utf-8')
  android_config = {}
  for element in raw_config.splitlines():
    if not element.startswith('='):
      key, value = tuple(element.split('=', 1))
      android_config.setdefault(key, value)
  return android_config


def get_config_gtest_args(test_config):
  """Get gtest's module-name and device-path option from the input config

  Args:
      test_config: The path of the test config.

  Returns:
      A string of gtest's module name.
      A string of gtest's device path.
  """
  module_name = ''
  device_path = ''
  xml_root = ET.parse(test_config).getroot()
  option_tags = xml_root.findall('.//option')
  for tag in option_tags:
    name = tag.attrib['name'].strip()
    value = tag.attrib['value'].strip()
    if name == 'native-test-device-path':
      device_path = value
    elif name == 'module-name':
      module_name = value
  return module_name, device_path


def get_arch_name(module_name, is_64=False):
  """Get the arch folder name for the input module.

  Scan the test case folders to get the matched arch folder name.

  Args:
      module_name: The module_name of test
      is_64: If need 64 bit arch name, False otherwise.

  Returns:
      A string of the arch name.
  """
  arch_32 = ['arm', 'x86']
  arch_64 = ['arm64', 'x86_64']
  arch_list = arch_32
  if is_64:
    arch_list = arch_64
  test_case_root = os.path.join(
      os.environ.get(constants.ANDROID_TARGET_OUT_TESTCASES, ''), module_name
  )
  if not os.path.isdir(test_case_root):
    logging.debug('%s does not exist.', test_case_root)
    return ''
  for f in os.listdir(test_case_root):
    if f in arch_list:
      return f
  return ''


def copy_single_arch_native_symbols(
    symbol_root, module_name, device_path, is_64=False
):
  """Copy symbol files for native tests which belong to input arch.

  Args:
      module_name: The module_name of test
      device_path: The device path define in test config.
      is_64: True if need to copy 64bit symbols, False otherwise.
  """
  src_symbol = os.path.join(symbol_root, 'data', 'nativetest', module_name)
  if is_64:
    src_symbol = os.path.join(symbol_root, 'data', 'nativetest64', module_name)
  dst_symbol = os.path.join(
      symbol_root,
      device_path[1:],
      module_name,
      get_arch_name(module_name, is_64),
  )
  if os.path.isdir(src_symbol):
    # TODO: Use shutil.copytree(src, dst, dirs_exist_ok=True) after
    #  python3.8
    if os.path.isdir(dst_symbol):
      shutil.rmtree(dst_symbol)
    shutil.copytree(src_symbol, dst_symbol)


def copy_native_symbols(module_name, device_path):
  """Copy symbol files for native tests to match with tradefed file structure.

  The original symbols will locate at
  $(PRODUCT_OUT)/symbols/data/nativetest(64)/$(module)/$(stem).
  From TF, the test binary will locate at
  /data/local/tmp/$(module)/$(arch)/$(stem).
  In order to make trace work need to copy the original symbol to
  $(PRODUCT_OUT)/symbols/data/local/tmp/$(module)/$(arch)/$(stem)

  Args:
      module_name: The module_name of test
      device_path: The device path define in test config.
  """
  symbol_root = os.path.join(
      os.environ.get(constants.ANDROID_PRODUCT_OUT, ''), 'symbols'
  )
  if not os.path.isdir(symbol_root):
    logging.debug('Symbol dir:%s not exist, skip copy symbols.', symbol_root)
    return
  # Copy 32 bit symbols
  if get_arch_name(module_name, is_64=False):
    copy_single_arch_native_symbols(
        symbol_root, module_name, device_path, is_64=False
    )
  # Copy 64 bit symbols
  if get_arch_name(module_name, is_64=True):
    copy_single_arch_native_symbols(
        symbol_root, module_name, device_path, is_64=True
    )


def get_config_preparer_options(test_config, class_name):
  """Get all the parameter values for the input config

  Args:
      test_config: The path of the test config.
      class_name: A string of target_preparer

  Returns:
      A set include all the parameters of the input config.
  """
  options = {}
  xml_root = ET.parse(test_config).getroot()
  option_tags = xml_root.findall(
      './/target_preparer[@class="%s"]/option' % class_name
  )
  for tag in option_tags:
    name = tag.attrib['name'].strip()
    value = tag.attrib['value'].strip()
    options[name] = value
  return options


def get_verify_key(tests, extra_args):
  """Compose test command key.

  Args:
      test_name: A list of input tests.
      extra_args: Dict of extra args to add to test run.

  Returns:
      A composed test commands.
  """
  # test_commands is a concatenated string of sorted test_ref+extra_args.
  # For example, "ITERATIONS=5 hello_world_test"
  test_commands = tests
  for key, value in extra_args.items():
    test_commands.append('%s=%s' % (key, str(value)))
  test_commands.sort()
  return ' '.join(test_commands)


def save_build_files_timestamp():
  """Method that generate timestamp of Android.{bp,mk} files.

  The checksum of build files are stores in
      $ANDROID_HOST_OUT/indices/buildfiles.stp
  """
  plocate_db = get_index_path(constants.LOCATE_CACHE)
  plocate_db_exist = plocate_db.is_file()
  logging.debug(
      'Build files timestamp db file %s exists: %s',
      plocate_db,
      plocate_db_exist,
  )

  if plocate_db_exist:
    cmd = f'locate -d{plocate_db} --existing ' r'--regex "/Android\.(bp|mk)$"'
    results = subprocess.getoutput(cmd)
    if results:
      timestamp = {}
      for build_file in results.splitlines():
        timestamp.update({build_file: Path(build_file).stat().st_mtime})

      timestamp_file = get_index_path(constants.BUILDFILES_STP)
      logging.debug('Writing to build files timestamp db %s', timestamp_file)
      with open(timestamp_file, 'w', encoding='utf-8') as _file:
        json.dump(timestamp, _file)


def run_multi_proc(func, *args, **kwargs):
  """Start a process with multiprocessing and return Process object.

  Args:
      func: A string of function name which will be the target name.
        args/kwargs: check doc page:
      https://docs.python.org/3.8/library/multiprocessing.html#process-and-exceptions

  Returns:
      multiprocessing.Process object.
  """
  proc = Process(target=func, *args, **kwargs)
  proc.start()
  return proc


def start_threading(target, *args, **kwargs):
  """Start a Thread-based parallelism.

  Args:
      func: A string of function name which will be the target name.
        args/kwargs: check doc page:
      https://docs.python.org/3/library/threading.html#threading.Thread

  Returns:
      threading.Thread object.
  """
  proc = Thread(target=target, *args, **kwargs)
  proc.start()
  return proc


def get_prebuilt_sdk_tools_dir():
  """Get the path for the prebuilt sdk tools root dir.

  Returns: The absolute path of prebuilt sdk tools directory.
  """
  build_top = Path(os.environ.get(constants.ANDROID_BUILD_TOP, ''))
  return build_top.joinpath(
      'prebuilts/sdk/tools/', str(platform.system()).lower(), 'bin'
  )


def is_writable(path):
  """Check if the given path is writable.

  Returns: True if input path is writable, False otherwise.
  """
  if not os.path.exists(path):
    return is_writable(os.path.dirname(path))
  return os.access(path, os.W_OK)


def get_misc_dir():
  """Get the path for the ATest data root dir.

  Returns: The absolute path of the ATest data root dir.
  """
  home_dir = os.path.expanduser('~')
  if is_writable(home_dir):
    return home_dir
  return get_build_out_dir()


def get_config_folder() -> Path:
  """Returns the config folder path where upload config is stored."""
  return Path(get_misc_dir()).joinpath('.atest')


def get_full_annotation_class_name(module_info, class_name):
  """Get fully qualified class name from a class name.

  If the given keyword(class_name) is "smalltest", this method can search
  among source codes and grep the accurate annotation class name:

      androidx.test.filters.SmallTest

  Args:
      module_info: A dict of module_info.
      class_name: A string of class name.

  Returns:
      A string of fully qualified class name, empty string otherwise.
  """
  fullname_re = re.compile(
      r'import\s+(?P<fqcn>{})(|;)$'.format(class_name), re.I
  )
  keyword_re = re.compile(
      r'import\s+(?P<fqcn>.*\.{})(|;)$'.format(class_name), re.I
  )
  build_top = Path(os.environ.get(constants.ANDROID_BUILD_TOP, ''))
  for f in module_info.get(constants.MODULE_SRCS, []):
    full_path = build_top.joinpath(f)
    with open(full_path, 'r', encoding='utf-8') as cache:
      for line in cache.readlines():
        # Accept full class name.
        match = fullname_re.match(line)
        if match:
          return match.group('fqcn')
        # Search annotation class from keyword.
        match = keyword_re.match(line)
        if match:
          return match.group('fqcn')
  return ''


def has_mixed_type_filters(test_infos):
  """There are different types in a test module.

  Dict test_to_types is mapping module name and the set of types.
  For example,
  {
      'module_1': {'wildcard class_method'},
      'module_2': {'wildcard class_method', 'regular class_method'},
      'module_3': set()
      }

  Args:
      test_infos: A set of TestInfos.

  Returns:
      True if more than one filter type in a test module, False otherwise.
  """
  test_to_types = {}
  for test_info in test_infos:
    filters = test_info.data.get(constants.TI_FILTER, [])
    filter_types = set()
    for flt in filters:
      filter_types |= get_filter_types(flt.to_list_of_tf_strings())
    filter_types |= test_to_types.get(test_info.test_name, set())
    test_to_types[test_info.test_name] = filter_types
  for _, types in test_to_types.items():
    if len(types) > 1:
      return True
  return False


def get_filter_types(tf_filter_set):
  """Get filter types.

  Args:
      tf_filter_set: A list of tf filter strings.

  Returns:
      A set of FilterType.
  """
  type_set = set()
  for tf_filter in tf_filter_set:
    if _WILDCARD_FILTER_RE.match(tf_filter):
      logging.debug(
          'Filter and type: (%s, %s)',
          tf_filter,
          FilterType.WILDCARD_FILTER.value,
      )
      type_set.add(FilterType.WILDCARD_FILTER.value)
    if _REGULAR_FILTER_RE.match(tf_filter):
      logging.debug(
          'Filter and type: (%s, %s)',
          tf_filter,
          FilterType.REGULAR_FILTER.value,
      )
      type_set.add(FilterType.REGULAR_FILTER.value)
  return type_set


def has_command(cmd: str) -> bool:
  """Detect if the command is available in PATH.

  Args:
      cmd: A string of the tested command.

  Returns:
      True if found, False otherwise.
  """
  return bool(shutil.which(cmd))


# pylint: disable=anomalous-backslash-in-string,too-many-branches
def get_bp_content(filename: Path, module_type: str) -> Dict:
  """Get essential content info from an Android.bp.

  By specifying module_type (e.g. 'android_test', 'android_app'), this method
  can parse the given starting point and grab 'name', 'instrumentation_for' and
  'manifest'.

  Returns:
      A dict of mapping test module and target module; e.g.
      {
       'FooUnitTests':
           {'manifest': 'AndroidManifest.xml', 'target_module': 'Foo'},
       'Foo':
           {'manifest': 'AndroidManifest-common.xml', 'target_module': ''}
      }
      Null dict if there is no content of the given module_type.
  """
  build_file = Path(filename)
  if not any((build_file.suffix == '.bp', build_file.is_file())):
    return {}
  start_from = re.compile(f'^{module_type}\s*\{{')
  end_with = re.compile(r'^\}$')
  context_re = re.compile(
      r'\s*(?P<key>(name|manifest|instrumentation_for))\s*:'
      r'\s*\"(?P<value>.*)\"\s*,',
      re.M,
  )
  with open(build_file, 'r', encoding='utf-8') as cache:
    data = cache.readlines()
  content_dict = {}
  start_recording = False
  for _line in data:
    line = _line.strip()
    if re.match(start_from, line):
      start_recording = True
      _dict = {}
      continue
    if start_recording:
      if not re.match(end_with, line):
        match = re.match(context_re, line)
        if match:
          _dict.update({match.group('key'): match.group('value')})
      else:
        start_recording = False
        module_name = _dict.get('name')
        if module_name:
          content_dict.update({
              module_name: {
                  'manifest': _dict.get('manifest', 'AndroidManifest.xml'),
                  'target_module': _dict.get('instrumentation_for', ''),
              }
          })
  return content_dict


def get_manifest_info(manifest: Path) -> Dict[str, Any]:
  """Get the essential info from the given manifest file.

  This method cares only three attributes:

      * package
      * targetPackage
      * persistent
  For an instrumentation test, the result will be like:
  {
      'package': 'com.android.foo.tests.unit',
      'targetPackage': 'com.android.foo',
      'persistent': False
  }
  For a target module of the instrumentation test:
  {
      'package': 'com.android.foo',
      'targetPackage': '',
      'persistent': True
  }
  """
  mdict = {'package': '', 'target_package': '', 'persistent': False}
  try:
    xml_root = ET.parse(manifest).getroot()
  except (ET.ParseError, FileNotFoundError):
    return mdict
  manifest_package_re = re.compile(r'[a-z][\w]+(\.[\w]+)*')
  # 1. Must probe 'package' name from the top.
  for item in xml_root.findall('.'):
    if 'package' in item.attrib.keys():
      pkg = item.attrib.get('package')
      match = manifest_package_re.match(pkg)
      if match:
        mdict['package'] = pkg
        break
  for item in xml_root.findall('*'):
    # 2. Probe 'targetPackage' in 'instrumentation' tag.
    if item.tag == 'instrumentation':
      for key, value in item.attrib.items():
        if 'targetPackage' in key:
          mdict['target_package'] = value
          break
    # 3. Probe 'persistent' in any tags.
    for key, value in item.attrib.items():
      if 'persistent' in key:
        mdict['persistent'] = value.lower() == 'true'
        break
  return mdict


# pylint: disable=broad-except
def generate_print_result_html(result_file: Path):
  """Generate a html that collects all log files."""
  result_file = Path(result_file)
  search_dir = Path(result_file).parent.joinpath('log')
  result_html = Path(search_dir, 'test_logs.html')
  try:
    logs = sorted(find_files(str(search_dir), file_name='*', followlinks=True))
    with open(result_html, 'w', encoding='utf-8') as cache:
      cache.write('<!DOCTYPE html><html><body>')
      result = load_json_safely(result_file)
      if result:
        cache.write(f'<h1>{"atest " + result.get("args")}</h1>')
        timestamp = datetime.datetime.fromtimestamp(result_file.stat().st_ctime)
        cache.write(f'<h2>{timestamp}</h2>')
      for log in logs:
        cache.write(
            f'<p><a href="{urllib.parse.quote(log)}">'
            f'{html.escape(Path(log).name)}</a></p>'
        )
      cache.write('</body></html>')
    print(
        f'\n{_HTML_LOG_PRINT_PREFIX}\n{mark_magenta(f"file://{result_html}")}\n'
    )
    send_tradeded_elapsed_time_metric(search_dir)
  except Exception as e:
    logging.debug('Did not generate log html for reason: %s', e)


def send_tradeded_elapsed_time_metric(search_dir: Path):
  """Method which sends Tradefed elapsed time to the metrics."""
  test, prep, teardown = get_tradefed_invocation_time(search_dir)
  metrics.LocalDetectEvent(
      detect_type=DetectType.TF_TOTAL_RUN_MS, result=test + prep + teardown
  )
  metrics.LocalDetectEvent(
      detect_type=DetectType.TF_PREPARATION_MS, result=prep
  )
  metrics.LocalDetectEvent(detect_type=DetectType.TF_TEST_MS, result=test)
  metrics.LocalDetectEvent(
      detect_type=DetectType.TF_TEARDOWN_MS, result=teardown
  )


def get_tradefed_invocation_time(search_dir: Path) -> Tuple[int, int, int]:
  """Return a tuple of testing, preparation and teardown time."""
  test, prep, teardown = 0, 0, 0
  end_host_log_files = find_files(
      path=search_dir, file_name='end_host_log_*.txt', followlinks=True
  )
  for log in end_host_log_files:
    with open(log, 'r', encoding='utf-8') as cache:
      contents = cache.read().splitlines()

    parse_test_time, parse_prep_time = False, False
    # ============================================
    # ================= Results ==================
    # =============== Consumed Time ==============
    #     x86_64 HelloWorldTests: 1s
    #     x86_64 hallo-welt: 866 ms
    # Total aggregated tests run time: 1s
    # ============== Modules Preparation Times ==============
    #     x86_64 HelloWorldTests => prep = 2483 ms || clean = 294 ms
    #     x86_64 hallo-welt => prep = 1845 ms || clean = 292 ms
    # Total preparation time: 4s  ||  Total tear down time: 586 ms
    # =======================================================
    # =============== Summary ===============
    # Total Run time: 6s
    # 2/2 modules completed
    # Total Tests       : 3
    # PASSED            : 3
    # FAILED            : 0
    # ============== End of Results ==============
    # ============================================
    for line in contents:
      if re.match(r'[=]+.*consumed.*time.*[=]+', line, re.I):
        parse_test_time, parse_prep_time = True, False
        continue
      if re.match(r'[=]+.*preparation.*time.*[=]+', line, re.I):
        parse_test_time, parse_prep_time = False, True
        continue
      # Close parsing when `Total` keyword starts at the beginning.
      if re.match(r'^(Total.*)', line, re.I):
        parse_test_time, parse_prep_time = False, False
        continue
      if parse_test_time:
        match = re.search(r'^[\s]+\w.*:\s+(?P<timestr>.*)$', line, re.I)
        if match:
          test += convert_timestr_to_ms(match.group('timestr'))
        continue
      if parse_prep_time:
        # SuiteResultReporter.java defines elapsed prep time only in ms.
        match = re.search(
            r'prep = (?P<prep>\d+ ms) \|\| clean = (?P<clean>\d+ ms)$',
            line,
            re.I,
        )
        if match:
          prep += convert_timestr_to_ms(match.group('prep'))
          teardown += convert_timestr_to_ms(match.group('clean'))
        continue

  return test, prep, teardown


def convert_timestr_to_ms(time_string: str = None) -> int:
  """Convert time string to an integer in millisecond.

  Possible time strings are:
      1h 21m 15s
      1m 5s
      25s
  If elapsed time is less than 1 sec, the time will be in millisecond.
      233 ms
  """
  if not time_string:
    return 0

  hours, minutes, seconds = 0, 0, 0
  # Extract hour(<h>), minute(<m>), second(<s>), or millisecond(<ms>).
  match = re.match(
      r'(((?P<h>\d+)h\s+)?(?P<m>\d+)m\s+)?(?P<s>\d+)s|(?P<ms>\d+)\s*ms',
      time_string,
  )
  if match:
    hours = int(match.group('h')) if match.group('h') else 0
    minutes = int(match.group('m')) if match.group('m') else 0
    seconds = int(match.group('s')) if match.group('s') else 0
    milliseconds = int(match.group('ms')) if match.group('ms') else 0

  return (
      hours * 3600 * 1000 + minutes * 60 * 1000 + seconds * 1000 + milliseconds
  )


# pylint: disable=broad-except
def prompt_suggestions(result_file: Path):
  """Generate suggestions when detecting keywords in logs."""
  result_file = Path(result_file)
  search_dir = Path(result_file).parent.joinpath('log')
  logs = sorted(find_files(str(search_dir), file_name='*'))
  for log in logs:
    for keyword, suggestion in SUGGESTIONS.items():
      try:
        with open(log, 'r', encoding='utf-8') as cache:
          content = cache.read()
          if keyword in content:
            colorful_print('[Suggestion] ' + suggestion, color=constants.RED)
            break
      # If the given is not a plain text, just ignore it.
      except Exception:
        pass


# pylint: disable=invalid-name
def get_rbe_and_customized_out_state() -> int:
  """Return decimal state of RBE and customized out.

  Customizing out dir (OUT_DIR/OUT_DIR_COMMON_BASE) dramatically slows down
  the RBE performance; by collecting the combined state of the two states,
  we can profile the performance relationship between RBE and the build time.

  Returns:
      An integer that describes the combined state.
  """
  #    RBE  | out_dir |  decimal
  # --------+---------+---------
  #     0   |    0    |    0
  #     0   |    1    |    1
  #     1   |    0    |    2
  #     1   |    1    |    3    --> Caution for poor performance.
  ON = '1'
  OFF = '0'
  # 1. ensure RBE is enabled during the build.
  actual_out_dir = get_build_out_dir()
  log_path = actual_out_dir.joinpath('soong.log')
  rbe_enabled = not bool(
      subprocess.call(f'grep -q USE_RBE=true {log_path}'.split())
  )
  rbe_state = ON if rbe_enabled else OFF

  # 2. The customized out path will be different from the regular one.
  regular_out_dir = Path(os.getenv(constants.ANDROID_BUILD_TOP), 'out')
  customized_out = OFF if actual_out_dir == regular_out_dir else ON

  return int(rbe_state + customized_out, 2)


def build_files_integrity_is_ok() -> bool:
  """Return Whether the integrity of build files is OK."""
  # 0. Missing timestamp file or plocate.db means a fresh repo sync.
  timestamp_file = get_index_path(constants.BUILDFILES_STP)
  locate_cache = get_index_path(constants.LOCATE_CACHE)
  if not timestamp_file.is_file():
    logging.debug('timestamp_file %s is missing', timestamp_file)
    return False
  if not locate_cache.is_file():
    logging.debug('locate_cache file %s is missing', locate_cache)
    return False

  # 1. Ensure no build files were added/deleted.
  recorded_amount = len(load_json_safely(timestamp_file).keys())
  cmd_out = subprocess.getoutput(
      f'locate -e -d{locate_cache} --regex ' r'"/Android\.(bp|mk)$" | wc -l'
  )
  if int(cmd_out) != recorded_amount:
    logging.debug(
        'Some build files are added/deleted. Recorded number of files: %s,'
        ' actual: %s',
        recorded_amount,
        cmd_out,
    )
    return False

  # 2. Ensure the consistency of all build files.
  for file, timestamp in load_json_safely(timestamp_file).items():
    if Path(file).exists() and Path(file).stat().st_mtime != timestamp:
      logging.debug(
          'A build file is changed: %s. Recorded timestamp: %s, actual'
          ' timestamp: %s',
          file,
          timestamp,
          Path(file).stat().st_mtime,
      )
      return False
  return True


def _build_env_profiling() -> BuildEnvProfiler:
  """Determine the status profile before build.

  The BuildEnvProfiler object can help use determine whether a build is:
      1. clean build. (empty out/ dir)
      2. Build files Integrity (Android.bp/Android.mk changes).
      3. Environment variables consistency.
      4. New Ninja file generated. (mtime of soong/build.ninja)

  Returns:
      the BuildProfile object.
  """
  out_dir = get_build_out_dir()
  ninja_file = out_dir.joinpath('soong/build.ninja')
  mtime = ninja_file.stat().st_mtime if ninja_file.is_file() else 0
  variables_file = out_dir.joinpath('soong/soong.environment.used.build')

  return BuildEnvProfiler(
      ninja_file=ninja_file,
      ninja_file_mtime=mtime,
      variable_file=variables_file,
      variable_file_md5=md5sum(variables_file),
      clean_out=not ninja_file.exists(),
      build_files_integrity=build_files_integrity_is_ok(),
  )


def _send_build_condition_metrics(
    build_profile: BuildEnvProfiler, cmd: List[str]
):
  """Send build conditions by comparing build env profilers."""

  # when build module-info.json only, 'module-info.json' will be
  # the last element.
  m_mod_info_only = 'module-info.json' in cmd.pop()

  def ninja_file_is_changed(env_profiler: BuildEnvProfiler) -> bool:
    """Determine whether the ninja file had been renewal."""
    if not env_profiler.ninja_file.is_file():
      return True
    return (
        env_profiler.ninja_file.stat().st_mtime != env_profiler.ninja_file_mtime
    )

  def env_var_is_changed(env_profiler: BuildEnvProfiler) -> bool:
    """Determine whether soong-related variables had changed."""
    return md5sum(env_profiler.variable_file) != env_profiler.variable_file_md5

  def send_data(detect_type, value=1):
    """A simple wrapper of metrics.LocalDetectEvent."""
    metrics.LocalDetectEvent(detect_type=detect_type, result=value)

  send_data(DetectType.RBE_STATE, get_rbe_and_customized_out_state())

  # Determine the correct detect type before profiling.
  # (build module-info.json or build dependencies.)
  clean_out = (
      DetectType.MODULE_INFO_CLEAN_OUT
      if m_mod_info_only
      else DetectType.BUILD_CLEAN_OUT
  )
  ninja_generation = (
      DetectType.MODULE_INFO_GEN_NINJA
      if m_mod_info_only
      else DetectType.BUILD_GEN_NINJA
  )
  bpmk_change = (
      DetectType.MODULE_INFO_BPMK_CHANGE
      if m_mod_info_only
      else DetectType.BUILD_BPMK_CHANGE
  )
  env_change = (
      DetectType.MODULE_INFO_ENV_CHANGE
      if m_mod_info_only
      else DetectType.BUILD_ENV_CHANGE
  )
  src_change = (
      DetectType.MODULE_INFO_SRC_CHANGE
      if m_mod_info_only
      else DetectType.BUILD_SRC_CHANGE
  )
  other = (
      DetectType.MODULE_INFO_OTHER
      if m_mod_info_only
      else DetectType.BUILD_OTHER
  )
  incremental = (
      DetectType.MODULE_INFO_INCREMENTAL
      if m_mod_info_only
      else DetectType.BUILD_INCREMENTAL
  )

  if build_profile.clean_out:
    send_data(clean_out)
  else:
    send_data(incremental)

  if ninja_file_is_changed(build_profile):
    send_data(ninja_generation)

  other_condition = True
  if not build_profile.build_files_integrity:
    send_data(bpmk_change)
    other_condition = False
  if env_var_is_changed(build_profile):
    send_data(env_change)
    other_condition = False
  if bool(get_modified_files(os.getcwd())):
    send_data(src_change)
    other_condition = False
  if other_condition:
    send_data(other)