# Copyright 2014 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import logging

from telemetry.testing import run_tests


def RunChromeOSTests(browser_type, tests_to_run):
  """ Run ChromeOS tests.
  Args:
    |browser_type|: string specifies which browser type to use.
    |tests_to_run|: a list of tuples (top_level_dir, unit_tests), whereas
      |top_level_dir| specifies the top level directory for running tests, and
      |unit_tests| is a list of string test names to run.
  """
  stream = _LoggingOutputStream()
  error_string = ''

  for (top_level_dir, unit_tests) in tests_to_run:
    logging.info('Running unit tests in %s with browser_type "%s".' %
                 (top_level_dir, browser_type))

    ret = _RunOneSetOfTests(browser_type, top_level_dir, unit_tests, stream)
    if ret:
      error_string += 'The unit tests of %s failed.\n' % top_level_dir
  return error_string


def _RunOneSetOfTests(browser_type, top_level_dir, tests, stream):
  args = ['--browser', browser_type,
          '--top-level-dir', top_level_dir,
          '--jobs', '1',
          '--disable-logging-config'] + tests
  return run_tests.RunTestsCommand.main(args, stream=stream)


class _LoggingOutputStream(object):

  def __init__(self):
    self._buffer = []

  def write(self, s):
    """Buffer a string write. Log it when we encounter a newline."""
    if '\n' in s:
      segments = s.split('\n')
      segments[0] = ''.join(self._buffer + [segments[0]])
      log_level = logging.getLogger().getEffectiveLevel()
      try:  # TODO(dtu): We need this because of crbug.com/394571
        logging.getLogger().setLevel(logging.INFO)
        for line in segments[:-1]:
          logging.info(line)
      finally:
        logging.getLogger().setLevel(log_level)
      self._buffer = [segments[-1]]
    else:
      self._buffer.append(s)

  def flush(self):
    pass