import os
import ycm_core
from clang_helpers import PrepareClangFlags

# Set this to the absolute path to the folder (NOT the file!) containing the
# compile_commands.json file to use that instead of 'flags'. See here for
# more details: http://clang.llvm.org/docs/JSONCompilationDatabase.html
# Most projects will NOT need to set this to anything; you can just change the
# 'flags' list of compilation flags. Notice that YCM itself uses that approach.
compilation_database_folder = ''

repl_tmpl = '(int)((x)[a]?(((long)((x)[a])<<a)^!):0)'
csh_lookup_str = '!'

for num in range(31):
    t_str = repl_tmpl.replace('a', str(num))
    csh_lookup_str = csh_lookup_str.replace('!', t_str)

csh_lookup_str = csh_lookup_str.replace('!', '0')

# These are the compilation flags that will be used in case there's no
# compilation database set.
flags = [
    '-g',
    '-Wall',
    '-Wstrict-prototypes',
    '-Wshadow',
    '-pthread',
    '-fno-strict-aliasing',
    '-I/usr/include/glib-2.0',
    '-I/usr/lib/x86_64-linux-gnu/glib-2.0/include',
    '-I/usr/include/json-glib-1.0',
    '-I/usr/include/mysql',
    '-pthread',
    '-I../kernel-module/',
    '-I../lib/',
    '-I../include/',
    '-I../daemon/',
    '-D_GNU_SOURCE',
    '-D__DEBUG=1',
    '-D__YCM=1',
    '-DPCRE2_CODE_UNIT_WIDTH=8',
    '-DRTPENGINE_VERSION="dummy"',
    '-DRE_PLUGIN_DIR="/usr/lib/rtpengine"',
    '-DWITH_IPTABLES_OPTION',
    '-DWITH_TRANSCODING',
    '-DHAVE_BCG729',
    '-DHAVE_MQTT',
    '-DHAVE_CODEC_CHAIN',
    '-DHAVE_LIBURING',
    '-D__csh_lookup(x)=str_hash(x)',
    '-DCSH_LOOKUP(x)=' + csh_lookup_str,
    '-O2',
    '-fstack-protector',
    '--param=ssp-buffer-size=4',
    '-Wformat',
    '-Werror=format-security',
    '-D_FORTIFY_SOURCE=2',
    # 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>".
    # For a C project, you would set this to something like 'c99' instead of
    # 'c++11'.
    '-std=c11',
    # ...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.
    # For a C project, you would set this to 'c' instead of 'c++'.
    '-x',
    'c',
]

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:
        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


def FlagsForFile(filename):
    if database:
        # Bear in mind that compilation_info.compiler_flags_ does NOT return a
        # python list, but a "list-like" StringVec object
        compilation_info = database.GetCompilationInfoForFile(filename)
        final_flags = PrepareClangFlags(
            MakeRelativePathsInFlagsAbsolute(
                compilation_info.compiler_flags_,
                compilation_info.compiler_working_dir_),
            filename)
    else:
        relative_to = DirectoryOfThisScript()
        final_flags = MakeRelativePathsInFlagsAbsolute(flags, relative_to)

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