#!/usr/bin/python
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU Library General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# enforce_licence.py
# Copyright (C) 2013 Simon Newton

from __future__ import print_function
import difflib
import getopt
import glob
import os
import pprint
import re
import sys
import textwrap

CPP, JS, PROTOBUF, PYTHON = xrange(4)

IGNORED_DIRECTORIES = [
  'javascript/new-src/node_modules/',
]

IGNORED_FILES = [
  'common/rdm/testdata/duplicate_manufacturer.proto',
  'common/rdm/testdata/duplicate_pid_name.proto',
  'common/rdm/testdata/duplicate_pid_value.proto',
  'common/rdm/testdata/inconsistent_pid.proto',
  'common/rdm/testdata/invalid_esta_pid.proto',
  'common/rdm/testdata/test_pids.proto',
  'common/rdm/testdata/pids/overrides.proto',
  'common/rdm/testdata/pids/pids1.proto',
  'common/rdm/testdata/pids/pids2.proto',
  'examples/ola-dmxconsole.cpp',
  'examples/ola-dmxmonitor.cpp',
  'include/ola/gen_callbacks.py',
  'olad/www/mobile.js',
  'olad/www/ola.js',
  'javascript/new-src/Gruntfile.js',
  'olad/www/new/js/app.min.js',
  'olad/www/new/js/app.min.js.map',
  'python/ola/PidStoreLocation.py',
  'python/ola/Version.py',
  'tools/ola_trigger/config.tab.cpp',
  'tools/ola_trigger/config.tab.h',
  'tools/ola_trigger/lex.yy.cpp',
  'tools/rdm/DataLocation.py',
  'tools/rdm/static/ui.multiselect.js',
]


def Usage(arg0):
  print(textwrap.dedent("""\
  Usage: %s

  Walk the directory tree from the current directory, and make sure all .cpp,
  .h, .js, .proto and .py files have the appropriate Licence. The licence is
  determined from the LICENCE file in each branch of the directory tree.

    --diff               Print the diffs.
    --fix                Fix the files.
    --help               Display this message.""" % arg0))


def ParseArgs():
  """Extract the options."""
  try:
    opts, args = getopt.getopt(sys.argv[1:], '',
                               ['diff', 'fix', 'help'])
  except getopt.GetoptError as e:
    print(str(e))
    Usage(sys.argv[0])
    sys.exit(2)

  help = False
  fix = False
  diff = False
  for o, a in opts:
    if o in ('--diff'):
      diff = True
    elif o in ('--fix'):
      fix = True
    elif o in ('-h', '--help'):
      Usage(sys.argv[0])
      sys.exit()

  if help:
    Usage(sys.argv[0])
    sys.exit(0)
  return diff, fix


def IgnoreFile(file_name):
  for ignored_dir in IGNORED_DIRECTORIES:
    if file_name.rfind(ignored_dir) != -1:
      return True
  for ignored_file in IGNORED_FILES:
    if file_name.endswith(ignored_file):
      return True
  return False


def TransformCppLine(line):
  """Transform a line to within a C++ multiline style comment"""
  line = line.strip()
  if line:
    return ' * %s' % line
  else:
    return ' *'


def TransformLicence(licence):
  """Wrap a licence in C++ style comments"""
  output = []
  output.append('/*')
  output.extend(map(TransformCppLine, licence))
  output.append(TransformCppLine(''))
  return '\n'.join(output)


def TransformJsLine(line):
  """Transform a line to within a JS multiline style comment"""
  return TransformCppLine(line)


def TransformCppToJsLicence(licence):
  """Change a C++ licence to JS style"""
  lines = licence.split('\n')
  output = []
  output.append('/**')
  for line in lines[1:]:
    output.append(TransformJsLine(line[2:]))
  return '\n'.join(output)


def TransformPythonLine(line):
  """Transform a line to within a Python multiline style comment"""
  line = line.strip()
  if line:
    return '# %s' % line
  else:
    return '#'


def TransformCppToPythonLicence(licence):
  """Change a C++ licence to Python style"""
  lines = licence.split('\n')
  output = []
  for line in lines[1:]:
    output.append(TransformPythonLine(line[3:]))
  return '\n'.join(output)


def TransformLine(line, lang):
  if lang == CPP or lang == PROTOBUF:
    return TransformCppLine(line)
  elif lang == JS:
    return TransformJsLine(line)
  elif lang == PYTHON:
    return TransformPythonLine(line)
  else:
    return line


def ReplaceHeader(file_name, new_header, lang):
  f = open(file_name)
  breaks = 0
  line = f.readline()
  while line != '':
    if (lang == CPP or lang == JS or lang == PROTOBUF) and \
       re.match(r'^ \*\s*\n$', line):
      breaks += 1
    if lang == PYTHON and re.match(r'^#\s*\n$', line):
      breaks += 1
    if breaks == 3:
      break
    line = f.readline()

  if breaks < 3:
    print("Couldn't find header for %s so couldn't fix it" % file_name)
    f.close()
    return

  remainder = f.read()
  f.close()

  f = open(file_name, 'w')
  f.write(new_header)
  f.write('\n')
  f.write(remainder)
  f.close()


def GetDirectoryLicences(root_dir):
  """Walk the directory tree and determine the licence for each directory."""
  LICENCE_FILE = 'LICENCE'
  licences = {}

  for dir_name, subdirs, files in os.walk(root_dir):
    # skip the root_dir since the licence file is different there
    if dir_name == root_dir:
      continue

    # skip ignored dirs since we don't check them anyways
    skip = False
    for ignored_dir in IGNORED_DIRECTORIES:
      if dir_name.rfind(ignored_dir) != -1:
        skip = True

    if skip:
      continue

    # don't descend into hidden dirs like .libs and .deps
    subdirs[:] = [d for d in subdirs if not d.startswith('.')]

    if LICENCE_FILE in files:
      f = open(os.path.join(dir_name, LICENCE_FILE))
      lines = f.readlines()
      f.close()
      licences[dir_name] = TransformLicence(lines)
      print('Found LICENCE for directory %s' % dir_name)

    # use this licence for all subdirs
    licence = licences.get(dir_name)
    if licence is not None:
      for sub_dir in subdirs:
        licences[os.path.join(dir_name, sub_dir)] = licence
  return licences


def CheckLicenceForDir(dir_name, licence, diff, fix):
  """Check all files in a directory contain the correct licence."""
  errors = 0
  # glob doesn't support { } so we iterate instead
  for match in ['*.h', '*.cpp']:
    for file_name in glob.glob(os.path.join(dir_name, match)):
      # skip the generated protobuf code
      if '.pb.' in file_name:
        continue
      errors += CheckLicenceForFile(file_name, licence, CPP, diff, fix)

  js_licence = TransformCppToJsLicence(licence)
  for file_name in glob.glob(os.path.join(dir_name, '*.js')):
    errors += CheckLicenceForFile(file_name, js_licence, JS, diff, fix)

  for file_name in glob.glob(os.path.join(dir_name, '*.proto')):
    errors += CheckLicenceForFile(file_name, licence, PROTOBUF, diff, fix)

  python_licence = TransformCppToPythonLicence(licence)
  for file_name in glob.glob(os.path.join(dir_name, '*.py')):
    # skip the generated protobuf code
    if file_name.endswith('__init__.py') or file_name.endswith('pb2.py'):
      continue
    errors += CheckLicenceForFile(file_name, python_licence, PYTHON, diff, fix)

  return errors


def CheckLicenceForFile(file_name, licence, lang, diff, fix):
  """Check a file contains the correct licence."""
  if IgnoreFile(file_name):
    return 0

  f = open(file_name)
  # + 1 to include the newline to have a complete line
  header_size = len(licence) + 1
  first_line = None
  if lang == PYTHON:
    first_line = f.readline()
    if not first_line.startswith('#!') and not first_line.startswith('# !'):
      # First line isn't a shebang, ignore it.
      f.seek(0, os.SEEK_SET)
      first_line = None
  # strip the trailing newline off as we don't actually want it
  header = f.read(header_size).rstrip('\n')
  file_name_line = f.readline()
  f.close()
  if header == licence:
    expected_line = TransformLine(os.path.basename(file_name), lang)
    if lang != JS and file_name_line.rstrip('\n') != expected_line:
      print("File %s does not have a filename line after the licence; found "
            "\"%s\" expected \"%s\"" %
            (file_name, file_name_line.rstrip('\n'), expected_line))
      return 1
    return 0

  if fix:
    print('Fixing %s' % file_name)
    if lang == PYTHON and first_line is not None:
      licence = first_line + licence
    ReplaceHeader(file_name, licence, lang)
    return 1
  else:
    print("File %s does not start with \"%s...\"" % (
        file_name,
        licence.split('\n')[(0 if (lang == PYTHON) else 1)]))
    if diff:
      d = difflib.Differ()
      result = list(d.compare(header.splitlines(1), licence.splitlines(1)))
      pprint.pprint(result)
    return 1


def main():
  diff, fix = ParseArgs()
  licences = GetDirectoryLicences(os.getcwd())
  errors = 0
  for dir_name, licence in licences.iteritems():
    errors += CheckLicenceForDir(dir_name, licence, diff=diff, fix=fix)
  print('Found %d files with incorrect licences' % errors)
  if errors > 0:
    sys.exit(1)
  else:
    sys.exit()


if __name__ == '__main__':
  main()