import os
import shlex
import subprocess
import ycm_core

def FlagsForFile( filename, **kwargs ):
  client_data = kwargs['client_data']
  cwd = client_data['getcwd()']
  # These are the compilation flags that will be used in case there's no
  # compilation database set (by default, one is not set).
  flags = [
  '-Wall',
  # '-Wextra',
  # '-Wshadow',
  # '-Werror',
  # '-Wc++98-compat',
  # '-Wno-long-long',
  # '-Wno-variadic-macros',
  # '-fexceptions',
  # '-DNDEBUG',
  '-std=c++11',
  '-stdlib=libstdc++',
  '-x', 'c++',
  '-I', '.',
  '-I', './include',
  ]
  flags += rospack()
  relative_to = cwd
  final_flags = MakeRelativePathsInFlagsAbsolute( flags, relative_to )

  return {
    'flags': final_flags,
    'do_cache': True
  }

# This function makes it easy to pull in additional flags from rospack
def rospack():
  cmd = ['rospack', 'cflags-only-I']
  try:
    out = subprocess.Popen(cmd, shell=False, stdout=subprocess.PIPE).stdout
  except:
    return []
  line = out.readline()[:-1].split(" ")
  includes = []
  for include in line:
    if include.startswith(os.path.expanduser('~')):
      includes += ['-I', include]
    else:
      includes += ['-isystem', include]
  return filter(lambda a: a != ' ', includes)


def DirectoryOfThisScript():
  return os.path.dirname( os.path.abspath( __file__ ) )

def MakeRelativePathsInFlagsAbsolute( flags, working_directory ):
  if not working_directory:
    return list( flags )
  new_flags = []
  make_next_absolute = False
  path_flags = [ '-isystem', '-I', '-iquote', '--sysroot=' ]
  for flag in flags:
    new_flag = flag

    if make_next_absolute:
      make_next_absolute = False
      if not flag.startswith( '/' ):
        new_flag = os.path.join( working_directory, flag )

    for path_flag in path_flags:
      if flag == path_flag:
        make_next_absolute = True
        break

      if flag.startswith( path_flag ):
        path = flag[ len( path_flag ): ]
        new_flag = path_flag + os.path.join( working_directory, path )
        break

    if new_flag:
      new_flags.append( new_flag )
  return new_flags