import os
import ycm_core
from clang_helpers import PrepareClangFlags

# Set this to the absolute path to the folder containing the
# compilation_database.json file to use that instead of 'flags'. See here for
# more details: http://clang.llvm.org/docs/JSONCompilationDatabase.html
compilation_database_folder = ''

# These are the compilation flags that will be used in case there's no
# compilation database set.
flags = [
'-Wall',
'-Wextra',
'-Werror',
'-Wc++98-compat',
'-Wno-long-long',
'-Wno-variadic-macros',
'-fexceptions',
'-DNDEBUG',
# THIS IS IMPORTANT! Without a "-std=<something>" flag, clang won't know which
# language to use when compiling headers. So it will guess. Badly. So C++
# headers will be compiled as C headers. You don't want that so ALWAYS specify
# a "-std=<something>"
'-std=c++11',
# ...and the same thing goes for the magic -x option which specifies the
# language that the files to be compiled are written in. This is mostly
# relevant for c++ headers.
'-x',
'c++',
'-isystem',
'../BoostParts',
'-isystem',
# This path will only work on OS X, but extra paths that don't exist are not
# harmful
'/System/Library/Frameworks/Python.framework/Headers',
'-isystem',
'../llvm/include',
'-isystem',
'../llvm/tools/clang/include',
'-I',
'.',
'-isystem',
'./tests/gmock/gtest',
'-isystem',
'./tests/gmock/gtest/include',
'-isystem',
'./tests/gmock',
'-isystem',
'./tests/gmock/include'
]

if compilation_database_folder:
  database = ycm_core.CompilationDatabase( compilation_database_folder )
else:
  database = None


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


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

    if make_next_absolute:
      make_next_absolute = False
      if not flag.startswith( '/' ):
        to_append = 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 ): ]
        to_append = path_flag + os.path.join( working_directory, path )
        break

    if to_append:
      new_flags.append( to_append )
  return new_flags


def FlagsForFile( filename ):
  if database:
    # Bear in mind that database.FlagsForFile does NOT return a python list, but
    # a "list-like" StringVec object
    working_directory = database.CompileCommandWorkingDirectoryForFile(
        filename )
    raw_flags = database.FlagsForFile( filename )
    final_flags = PrepareClangFlags(
        MakeRelativePathsInFlagsAbsolute( raw_flags,
                                          working_directory ),
        filename )

    # NOTE: This is just for YouCompleteMe; it's highly likely that your project
    # does NOT need to remove the stdlib flag. DO NOT USE THIS IN YOUR
    # ycm_clang_options IF YOU'RE NOT 100% YOU NEED IT.
    try:
      final_flags.remove( '-stdlib=libc++' )
    except ValueError:
      pass
  else:
    relative_to = DirectoryOfThisScript()
    final_flags = MakeRelativePathsInFlagsAbsolute( flags, relative_to )

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