#!/usr/bin/python
#

# Copyright (C) 2011, 2014 Google Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
# IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


"""Script to verify file header.

"""

# pylint: disable=C0103
# [C0103] Invalid name

import sys
import re
import itertools

from ganeti import constants
from ganeti import utils
from ganeti import compat


#: Assume header is always in the first 8kB of a file
_READ_SIZE = 8 * 1024

_BSD2 = [
  "All rights reserved.",
  "",
  "Redistribution and use in source and binary forms, with or without",
  "modification, are permitted provided that the following conditions are",
  "met:",
  "",
  "1. Redistributions of source code must retain the above copyright notice,",
  "this list of conditions and the following disclaimer.",
  "",
  "2. Redistributions in binary form must reproduce the above copyright",
  "notice, this list of conditions and the following disclaimer in the",
  "documentation and/or other materials provided with the distribution.",
  "",
  "THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS \"AS",
  "IS\" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED",
  "TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR",
  "PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR",
  "CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,",
  "EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,",
  "PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR",
  "PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF",
  "LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING",
  "NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS",
  "SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.",
  ]


_SHEBANG = re.compile(r"^#(?:|!(?:/usr/bin/python(?:| -u)|/bin/(?:|ba)sh))$")
_COPYRIGHT_YEAR = r"20[01][0-9]"
_COPYRIGHT = re.compile(r"# Copyright \(C\) (%s(?:, %s)*) Google Inc\.$" %
                        (_COPYRIGHT_YEAR, _COPYRIGHT_YEAR))
_COPYRIGHT_DESC = "Copyright (C) <year>[, <year> ...] Google Inc."
_AUTOGEN = "# This file is automatically generated, do not edit!"


class HeaderError(Exception):
  pass


def _Fail(lineno, msg):
  raise HeaderError("Line %s: %s" % (lineno, msg))


def _CheckHeader(getline_fn):
  (lineno, line) = getline_fn()

  if line == _AUTOGEN:
    return

  if not _SHEBANG.match(line):
    _Fail(lineno, ("Must contain nothing but a hash character (#) or a"
                   " shebang line (e.g. #!/bin/bash)"))

  (lineno, line) = getline_fn()

  if line == _AUTOGEN:
    return

  if line != "#":
    _Fail(lineno, "Must contain nothing but hash character (#)")

  (lineno, line) = getline_fn()
  if line:
    _Fail(lineno, "Must be empty")

  (lineno, line) = getline_fn()
  if not _COPYRIGHT.match(line):
    _Fail(lineno, "Must contain copyright information (%s)" % _COPYRIGHT_DESC)

  for licence_line in _BSD2:
    (lineno, line) = getline_fn()
    if line != ("# %s" % licence_line).rstrip():
      _Fail(lineno, "Does not match expected licence line (%s)" % licence_line)

  (lineno, line) = getline_fn()
  if line:
    _Fail(lineno, "Must be empty")


def Main():
  """Main program.

  """
  fail = False

  for filename in sys.argv[1:]:
    content = utils.ReadFile(filename, size=_READ_SIZE)
    lines = zip(itertools.count(1), content.splitlines())

    try:
      _CheckHeader(compat.partial(lines.pop, 0))
    except HeaderError, err:
      report = str(err)
      print "%s: %s" % (filename, report)
      fail = True

  if fail:
    sys.exit(constants.EXIT_FAILURE)
  else:
    sys.exit(constants.EXIT_SUCCESS)


if __name__ == "__main__":
  Main()