# Copyright 2022 the V8 project authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

from contextlib import contextmanager
import os
import signal

import subprocess
import sys

from ..local.android import Driver
from .command import AndroidCommand, PosixCommand, WindowsCommand, taskkill_windows
from .pool import DefaultExecutionPool
from ..testproc.util import list_processes_linux


class DefaultOSContext:

  def __init__(self, command, pool=None):
    self.command = command
    self.pool = pool or DefaultExecutionPool(self)

  @contextmanager
  def handle_context(self, options):
    yield

  def list_processes(self):
    return []

  def terminate_process(self, process):
    pass


class LinuxContext(DefaultOSContext):

  def __init__(self):
    super().__init__(PosixCommand)

  def list_processes(self):
    return list_processes_linux()

  def terminate_process(self, process):
    os.kill(process.pid, signal.SIGTERM)


class WindowsContext(DefaultOSContext):

  def __init__(self):
    super().__init__(WindowsCommand)

  def terminate_process(self, process):
    taskkill_windows(process, verbose=True, force=False)


class AndroidOSContext(DefaultOSContext):

  def __init__(self):
    super().__init__(AndroidCommand)

  @contextmanager
  def handle_context(self, options):
    try:
      AndroidCommand.driver = Driver.instance(options.device)
      yield
    finally:
      AndroidCommand.driver.tear_down()


# TODO(liviurau): Add documentation with diagrams to describe how context and
# its components gets initialized and eventually teared down and how does it
# interact with both tests and underlying platform specific concerns.
def find_os_context_factory(target_os):
  registry = dict(android=AndroidOSContext, windows=WindowsContext)
  default = LinuxContext
  return registry.get(target_os, default)


@contextmanager
def os_context(target_os, options):
  factory = find_os_context_factory(target_os)
  context_instance = factory()
  with context_instance.handle_context(options):
    yield context_instance