#!/usr/bin/env python3
#
# Copyright (C) 2016 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.

"""Module containing common logic from python testing tools."""

import abc
import os
import signal
import shlex
import shutil
import time

from enum import Enum
from enum import unique

from subprocess import DEVNULL
from subprocess import check_call
from subprocess import PIPE
from subprocess import Popen
from subprocess import STDOUT
from subprocess import TimeoutExpired

from tempfile import mkdtemp
from tempfile import NamedTemporaryFile

# Temporary directory path on device.
DEVICE_TMP_PATH = '/data/local/tmp'

# Architectures supported in dalvik cache.
DALVIK_CACHE_ARCHS = ['arm', 'arm64', 'x86', 'x86_64']


@unique
class RetCode(Enum):
  """Enum representing normalized return codes."""
  SUCCESS = 0
  TIMEOUT = 1
  ERROR = 2
  NOTCOMPILED = 3
  NOTRUN = 4


@unique
class LogSeverity(Enum):
  VERBOSE = 0
  DEBUG = 1
  INFO = 2
  WARNING = 3
  ERROR = 4
  FATAL = 5
  SILENT = 6

  @property
  def symbol(self):
    return self.name[0]

  @classmethod
  def FromSymbol(cls, s):
    for log_severity in LogSeverity:
      if log_severity.symbol == s:
        return log_severity
    raise ValueError("{0} is not a valid log severity symbol".format(s))

  def __ge__(self, other):
    if self.__class__ is other.__class__:
      return self.value >= other.value
    return NotImplemented

  def __gt__(self, other):
    if self.__class__ is other.__class__:
      return self.value > other.value
    return NotImplemented

  def __le__(self, other):
    if self.__class__ is other.__class__:
      return self.value <= other.value
    return NotImplemented

  def __lt__(self, other):
    if self.__class__ is other.__class__:
      return self.value < other.value
    return NotImplemented


def GetEnvVariableOrError(variable_name):
  """Gets value of an environmental variable.

  If the variable is not set raises FatalError.

  Args:
    variable_name: string, name of variable to get.

  Returns:
    string, value of requested variable.

  Raises:
    FatalError: Requested variable is not set.
  """
  top = os.environ.get(variable_name)
  if top is None:
    raise FatalError('{0} environmental variable not set.'.format(
        variable_name))
  return top


def _DexArchCachePaths(android_data_path):
  """Returns paths to architecture specific caches.

  Args:
    android_data_path: string, path dalvik-cache resides in.

  Returns:
    Iterable paths to architecture specific caches.
  """
  return ('{0}/dalvik-cache/{1}'.format(android_data_path, arch)
          for arch in DALVIK_CACHE_ARCHS)


def RunCommandForOutput(cmd, env, stdout, stderr, timeout=60):
  """Runs command piping output to files, stderr or stdout.

  Args:
    cmd: list of strings, command to run.
    env: shell environment to run the command with.
    stdout: file handle or one of Subprocess.PIPE, Subprocess.STDOUT,
      Subprocess.DEVNULL, see Popen.
    stderr: file handle or one of Subprocess.PIPE, Subprocess.STDOUT,
      Subprocess.DEVNULL, see Popen.
    timeout: int, timeout in seconds.

  Returns:
    tuple (string, string, RetCode) stdout output, stderr output, normalized
      return code.
  """
  proc = Popen(cmd, stdout=stdout, stderr=stderr, env=env,
               universal_newlines=True, start_new_session=True)
  try:
    (output, stderr_output) = proc.communicate(timeout=timeout)
    if proc.returncode == 0:
      retcode = RetCode.SUCCESS
    else:
      retcode = RetCode.ERROR
  except TimeoutExpired:
    os.killpg(os.getpgid(proc.pid), signal.SIGTERM)
    (output, stderr_output) = proc.communicate()
    retcode = RetCode.TIMEOUT
  return (output, stderr_output, retcode)


def _LogCmdOutput(logfile, cmd, output, retcode):
  """Logs output of a command.

  Args:
    logfile: file handle to logfile.
    cmd: list of strings, command.
    output: command output.
    retcode: RetCode, normalized retcode.
  """
  logfile.write('Command:\n{0}\n{1}\nReturn code: {2}\n'.format(
      CommandListToCommandString(cmd), output, retcode))


def RunCommand(cmd, out, err, timeout=5):
  """Executes a command, and returns its return code.

  Args:
    cmd: list of strings, a command to execute
    out: string, file name to open for stdout (or None)
    err: string, file name to open for stderr (or None)
    timeout: int, time out in seconds
  Returns:
    RetCode, return code of running command (forced RetCode.TIMEOUT
    on timeout)
  """
  devnull = DEVNULL
  outf = devnull
  if out is not None:
    outf = open(out, mode='w')
  errf = devnull
  if err is not None:
    errf = open(err, mode='w')
  (_, _, retcode) = RunCommandForOutput(cmd, None, outf, errf, timeout)
  if outf != devnull:
    outf.close()
  if errf != devnull:
    errf.close()
  return retcode


def CommandListToCommandString(cmd):
  """Converts shell command represented as list of strings to a single string.

  Each element of the list is wrapped in double quotes.

  Args:
    cmd: list of strings, shell command.

  Returns:
    string, shell command.
  """
  return ' '.join([shlex.quote(segment) for segment in cmd])


class FatalError(Exception):
  """Fatal error in script."""


class ITestEnv(object):
  """Test environment abstraction.

  Provides unified interface for interacting with host and device test
  environments. Creates a test directory and expose methods to modify test files
  and run commands.
  """
  __meta_class__ = abc.ABCMeta

  @abc.abstractmethod
  def CreateFile(self, name=None):
    """Creates a file in test directory.

    Returned path to file can be used in commands run in the environment.

    Args:
      name: string, file name. If None file is named arbitrarily.

    Returns:
      string, environment specific path to file.
    """

  @abc.abstractmethod
  def WriteLines(self, file_path, lines):
    """Writes lines to a file in test directory.

    If file exists it gets overwritten. If file doest not exist it is created.

    Args:
      file_path: string, environment specific path to file.
      lines: list of strings to write.
    """

  @abc.abstractmethod
  def RunCommand(self, cmd, log_severity=LogSeverity.ERROR):
    """Runs command in environment.

    Args:
      cmd: list of strings, command to run.
      log_severity: LogSeverity, minimum severity of logs included in output.
    Returns:
      tuple (string, int) output, return code.
    """

  @abc.abstractproperty
  def logfile(self):
    """Gets file handle to logfile residing on host."""


class HostTestEnv(ITestEnv):
  """Host test environment. Concrete implementation of ITestEnv.

  Maintains a test directory in /tmp/. Runs commands on the host in modified
  shell environment. Mimics art script behavior.

  For methods documentation see base class.
  """

  def __init__(self, directory_prefix, cleanup=True, logfile_path=None,
               timeout=60, x64=False):
    """Constructor.

    Args:
      directory_prefix: string, prefix for environment directory name.
      cleanup: boolean, if True remove test directory in destructor.
      logfile_path: string, can be used to specify custom logfile location.
      timeout: int, seconds, time to wait for single test run to finish.
      x64: boolean, whether to setup in x64 mode.
    """
    self._cleanup = cleanup
    self._timeout = timeout
    self._env_path = mkdtemp(dir='/tmp/', prefix=directory_prefix)
    if logfile_path is None:
      self._logfile = open('{0}/log'.format(self._env_path), 'w+')
    else:
      self._logfile = open(logfile_path, 'w+')
    os.mkdir('{0}/dalvik-cache'.format(self._env_path))
    for arch_cache_path in _DexArchCachePaths(self._env_path):
      os.mkdir(arch_cache_path)
    lib = 'lib64' if x64 else 'lib'
    android_root = GetEnvVariableOrError('ANDROID_HOST_OUT')
    android_runtime_root = android_root + '/com.android.runtime'
    android_tzdata_root = android_root + '/com.android.tzdata'
    library_path = android_root + '/' + lib
    path = android_root + '/bin'
    self._shell_env = os.environ.copy()
    self._shell_env['ANDROID_DATA'] = self._env_path
    self._shell_env['ANDROID_ROOT'] = android_root
    self._shell_env['ANDROID_RUNTIME_ROOT'] = android_runtime_root
    self._shell_env['ANDROID_TZDATA_ROOT'] = android_tzdata_root
    self._shell_env['LD_LIBRARY_PATH'] = library_path
    self._shell_env['DYLD_LIBRARY_PATH'] = library_path
    self._shell_env['PATH'] = (path + ':' + self._shell_env['PATH'])
    # Using dlopen requires load bias on the host.
    self._shell_env['LD_USE_LOAD_BIAS'] = '1'

  def __del__(self):
    if self._cleanup:
      shutil.rmtree(self._env_path)

  def CreateFile(self, name=None):
    if name is None:
      f = NamedTemporaryFile(dir=self._env_path, delete=False)
    else:
      f = open('{0}/{1}'.format(self._env_path, name), 'w+')
    return f.name

  def WriteLines(self, file_path, lines):
    with open(file_path, 'w') as f:
      f.writelines('{0}\n'.format(line) for line in lines)
    return

  def RunCommand(self, cmd, log_severity=LogSeverity.ERROR):
    self._EmptyDexCache()
    env = self._shell_env.copy()
    env.update({'ANDROID_LOG_TAGS':'*:' + log_severity.symbol.lower()})
    (output, err_output, retcode) = RunCommandForOutput(
        cmd, env, PIPE, PIPE, self._timeout)
    # We append err_output to output to stay consistent with DeviceTestEnv
    # implementation.
    output += err_output
    _LogCmdOutput(self._logfile, cmd, output, retcode)
    return (output, retcode)

  @property
  def logfile(self):
    return self._logfile

  def _EmptyDexCache(self):
    """Empties dex cache.

    Iterate over files in architecture specific cache directories and remove
    them.
    """
    for arch_cache_path in _DexArchCachePaths(self._env_path):
      for file_path in os.listdir(arch_cache_path):
        file_path = '{0}/{1}'.format(arch_cache_path, file_path)
        if os.path.isfile(file_path):
          os.unlink(file_path)


class DeviceTestEnv(ITestEnv):
  """Device test environment. Concrete implementation of ITestEnv.

  For methods documentation see base class.
  """

  def __init__(self, directory_prefix, cleanup=True, logfile_path=None,
               timeout=60, specific_device=None):
    """Constructor.

    Args:
      directory_prefix: string, prefix for environment directory name.
      cleanup: boolean, if True remove test directory in destructor.
      logfile_path: string, can be used to specify custom logfile location.
      timeout: int, seconds, time to wait for single test run to finish.
      specific_device: string, serial number of device to use.
    """
    self._cleanup = cleanup
    self._timeout = timeout
    self._specific_device = specific_device
    self._host_env_path = mkdtemp(dir='/tmp/', prefix=directory_prefix)
    if logfile_path is None:
      self._logfile = open('{0}/log'.format(self._host_env_path), 'w+')
    else:
      self._logfile = open(logfile_path, 'w+')
    self._device_env_path = '{0}/{1}'.format(
        DEVICE_TMP_PATH, os.path.basename(self._host_env_path))
    self._shell_env = os.environ.copy()

    self._AdbMkdir('{0}/dalvik-cache'.format(self._device_env_path))
    for arch_cache_path in _DexArchCachePaths(self._device_env_path):
      self._AdbMkdir(arch_cache_path)

  def __del__(self):
    if self._cleanup:
      shutil.rmtree(self._host_env_path)
      check_call(shlex.split(
          'adb shell if [ -d "{0}" ]; then rm -rf "{0}"; fi'
          .format(self._device_env_path)))

  def CreateFile(self, name=None):
    with NamedTemporaryFile(mode='w') as temp_file:
      self._AdbPush(temp_file.name, self._device_env_path)
      if name is None:
        name = os.path.basename(temp_file.name)
      return '{0}/{1}'.format(self._device_env_path, name)

  def WriteLines(self, file_path, lines):
    with NamedTemporaryFile(mode='w') as temp_file:
      temp_file.writelines('{0}\n'.format(line) for line in lines)
      temp_file.flush()
      self._AdbPush(temp_file.name, file_path)
    return

  def _ExtractPid(self, brief_log_line):
    """Extracts PID from a single logcat line in brief format."""
    pid_start_idx = brief_log_line.find('(') + 2
    if pid_start_idx == -1:
      return None
    pid_end_idx = brief_log_line.find(')', pid_start_idx)
    if pid_end_idx == -1:
      return None
    return brief_log_line[pid_start_idx:pid_end_idx]

  def _ExtractSeverity(self, brief_log_line):
    """Extracts LogSeverity from a single logcat line in brief format."""
    if not brief_log_line:
      return None
    return LogSeverity.FromSymbol(brief_log_line[0])

  def RunCommand(self, cmd, log_severity=LogSeverity.ERROR):
    self._EmptyDexCache()
    env_vars_cmd = 'ANDROID_DATA={0} ANDROID_LOG_TAGS=*:i'.format(
        self._device_env_path)
    adb_cmd = ['adb']
    if self._specific_device:
      adb_cmd += ['-s', self._specific_device]
    logcat_cmd = adb_cmd + ['logcat', '-v', 'brief', '-s', '-b', 'main',
                            '-T', '1', 'dex2oat:*', 'dex2oatd:*']
    logcat_proc = Popen(logcat_cmd, stdout=PIPE, stderr=STDOUT,
                        universal_newlines=True)
    cmd_str = CommandListToCommandString(cmd)
    # Print PID of the shell and exec command. We later retrieve this PID and
    # use it to filter dex2oat logs, keeping those with matching parent PID.
    device_cmd = ('echo $$ && ' + env_vars_cmd + ' exec ' + cmd_str)
    cmd = adb_cmd + ['shell', device_cmd]
    (output, _, retcode) = RunCommandForOutput(cmd, self._shell_env, PIPE,
                                               STDOUT, self._timeout)
    # We need to make sure to only kill logcat once all relevant logs arrive.
    # Sleep is used for simplicity.
    time.sleep(0.5)
    logcat_proc.kill()
    end_of_first_line = output.find('\n')
    if end_of_first_line != -1:
      parent_pid = output[:end_of_first_line]
      output = output[end_of_first_line + 1:]
      logcat_output, _ = logcat_proc.communicate()
      logcat_lines = logcat_output.splitlines(keepends=True)
      dex2oat_pids = []
      for line in logcat_lines:
        # Dex2oat was started by our runtime instance.
        if 'Running dex2oat (parent PID = ' + parent_pid in line:
          dex2oat_pids.append(self._ExtractPid(line))
          break
      if dex2oat_pids:
        for line in logcat_lines:
          if (self._ExtractPid(line) in dex2oat_pids and
              self._ExtractSeverity(line) >= log_severity):
            output += line
    _LogCmdOutput(self._logfile, cmd, output, retcode)
    return (output, retcode)

  @property
  def logfile(self):
    return self._logfile

  def PushClasspath(self, classpath):
    """Push classpath to on-device test directory.

    Classpath can contain multiple colon separated file paths, each file is
    pushed. Returns analogous classpath with paths valid on device.

    Args:
      classpath: string, classpath in format 'a/b/c:d/e/f'.
    Returns:
      string, classpath valid on device.
    """
    paths = classpath.split(':')
    device_paths = []
    for path in paths:
      device_paths.append('{0}/{1}'.format(
          self._device_env_path, os.path.basename(path)))
      self._AdbPush(path, self._device_env_path)
    return ':'.join(device_paths)

  def _AdbPush(self, what, where):
    check_call(shlex.split('adb push "{0}" "{1}"'.format(what, where)),
               stdout=self._logfile, stderr=self._logfile)

  def _AdbMkdir(self, path):
    check_call(shlex.split('adb shell mkdir "{0}" -p'.format(path)),
               stdout=self._logfile, stderr=self._logfile)

  def _EmptyDexCache(self):
    """Empties dex cache."""
    for arch_cache_path in _DexArchCachePaths(self._device_env_path):
      cmd = 'adb shell if [ -d "{0}" ]; then rm -f "{0}"/*; fi'.format(
          arch_cache_path)
      check_call(shlex.split(cmd), stdout=self._logfile, stderr=self._logfile)