import os

from absl import flags

FLAGS = flags.FLAGS


def get_executable_path(py_binary_name):
  """Returns the executable path of a py_binary.

  This returns the executable path of a py_binary that is in another Bazel
  target's data dependencies.

  On Linux/macOS, the path and __file__ has the same root directory.
  On Windows, bazel builds an .exe file and we need to use the MANIFEST file
  the location the actual binary.

  Args:
    py_binary_name: string, the name of a py_binary that is in another Bazel
        target's data dependencies.

  Raises:
    RuntimeError: Raised when it cannot locate the executable path.
  """

  if os.name == 'nt':
    py_binary_name += '.exe'
    manifest_file = os.path.join(FLAGS.test_srcdir, 'MANIFEST')
    workspace_name = os.environ['TEST_WORKSPACE']
    manifest_entry = '{}/{}'.format(workspace_name, py_binary_name)
    with open(manifest_file, 'r') as manifest_fd:
      for line in manifest_fd:
        tokens = line.strip().split(' ')
        if len(tokens) != 2:
          continue
        if manifest_entry == tokens[0]:
          return tokens[1]
    raise RuntimeError(
        'Cannot locate executable path for {}, MANIFEST file: {}.'.format(
            py_binary_name, manifest_file))
  else:
    # NOTE: __file__ may be .py or .pyc, depending on how the module was
    # loaded and executed.
    path = __file__

    # Use the package name to find the root directory: every dot is
    # a directory, plus one for ourselves.
    for _ in range(__name__.count('.') + 1):
      path = os.path.dirname(path)

    root_directory = path
    return os.path.join(root_directory, py_binary_name)
