# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Run lint checks on the specified files."""

import os
import sys

from chromite.cbuildbot import constants
from chromite.lib import cros_build_lib
from chromite.lib import git

from chromite import cros


PYTHON_EXTENSIONS = frozenset(['.py'])

# Note these are defined to keep in line with cpplint.py. Technically, we could
# include additional ones, but cpplint.py would just filter them out.
CPP_EXTENSIONS = frozenset(['.cc', '.cpp', '.h'])


def _GetProjectPath(path):
  """Find the absolute path of the git checkout that contains |path|."""
  if git.FindRepoCheckoutRoot(path):
    manifest = git.ManifestCheckout.Cached(path)
    return manifest.FindCheckoutFromPath(path).GetPath(absolute=True)
  else:
    # Maybe they're running on a file outside of a checkout.
    # e.g. cros lint ~/foo.py /tmp/test.py
    return os.path.dirname(path)


def _GetPylintGroups(paths):
  """Return a dictionary mapping pylintrc files to lists of paths."""
  groups = {}
  for path in paths:
    if path.endswith('.py'):
      path = os.path.realpath(path)
      project_path = _GetProjectPath(path)
      parent = os.path.dirname(path)
      while project_path and parent.startswith(project_path):
        pylintrc = os.path.join(parent, 'pylintrc')
        if os.path.isfile(pylintrc):
          break
        parent = os.path.dirname(parent)
      if project_path is None or not os.path.isfile(pylintrc):
        pylintrc = os.path.join(constants.SOURCE_ROOT, 'chromite', 'pylintrc')
      groups.setdefault(pylintrc, []).append(path)
  return groups


def _GetPythonPath(paths):
  """Return the set of Python library paths to use."""
  return sys.path + [
    # Add the Portage installation inside the chroot to the Python path.
    # This ensures that scripts that need to import portage can do so.
    os.path.join(constants.SOURCE_ROOT, 'chroot', 'usr', 'lib', 'portage',
                 'pym'),

    # Scripts outside of chromite expect the scripts in src/scripts/lib to
    # be importable.
    os.path.join(constants.CROSUTILS_DIR, 'lib'),

    # Allow platform projects to be imported by name (e.g. crostestutils).
    os.path.join(constants.SOURCE_ROOT, 'src', 'platform'),

    # Ideally we'd modify meta_path in pylint to handle our virtual chromite
    # module, but that's not possible currently.  We'll have to deal with
    # that at some point if we want `cros lint` to work when the dir is not
    # named 'chromite'.
    constants.SOURCE_ROOT,

    # Also allow scripts to import from their current directory.
  ] + list(set(os.path.dirname(x) for x in paths))


def _CpplintFiles(files, debug):
  """Returns true if cpplint ran successfully on all files."""
  cmd = [os.path.join(constants.DEPOT_TOOLS_DIR, 'cpplint.py')] + files
  res = cros_build_lib.RunCommand(cmd,
                                  error_code_ok=True,
                                  print_cmd=debug)
  return res.returncode != 0


def _PylintFiles(files, debug):
  """Returns true if pylint ran successfully on all files."""
  errors = False
  for pylintrc, paths in sorted(_GetPylintGroups(files).items()):
    paths = sorted(list(set([os.path.realpath(x) for x in paths])))
    cmd = ['pylint', '--rcfile=%s' % pylintrc] + paths
    extra_env = {'PYTHONPATH': ':'.join(_GetPythonPath(paths))}
    res = cros_build_lib.RunCommand(cmd, extra_env=extra_env,
                                    error_code_ok=True,
                                    print_cmd=debug)
    if res.returncode != 0:
      errors = True

  return errors


def _BreakoutFilesByLinter(files):
  """Maps a linter method to the list of files to lint."""
  map_to_return = {}
  for f in files:
    extension = os.path.splitext(f)[1]
    if extension in PYTHON_EXTENSIONS:
      pylint_list = map_to_return.setdefault(_PylintFiles, [])
      pylint_list.append(f)
    elif extension in CPP_EXTENSIONS:
      cpplint_list = map_to_return.setdefault(_CpplintFiles, [])
      cpplint_list.append(f)

  return map_to_return


@cros.CommandDecorator('lint')
class LintCommand(cros.CrosCommand):
  """Run lint checks on the specified files."""

  EPILOG = """
Right now, only supports cpplint and pylint. We may also in the future
run other checks (e.g. pyflakes, etc.)
"""

  @classmethod
  def AddParser(cls, parser):
    super(LintCommand, cls).AddParser(parser)
    parser.add_argument('files', help='Files to lint', nargs='*')

  def Run(self):
    files = self.options.files
    if not files:
      # Running with no arguments is allowed to make the repo upload hook
      # simple, but print a warning so that if someone runs this manually
      # they are aware that nothing was linted.
      cros_build_lib.Warning('No files provided to lint.  Doing nothing.')

    errors = False
    linter_map = _BreakoutFilesByLinter(files)
    for linter, files in linter_map.iteritems():
      errors = linter(files, self.options.debug)

    if errors:
      sys.exit(1)