import sysconfig
import os
import shutil
import subprocess

from .. import knobs


def _build(name: str, src: str, srcdir: str, library_dirs: list[str], include_dirs: list[str],
           libraries: list[str]) -> str:
    if impl := knobs.build.impl:
        return impl(name, src, srcdir, library_dirs, include_dirs, libraries)
    suffix = sysconfig.get_config_var('EXT_SUFFIX')
    so = os.path.join(srcdir, '{name}{suffix}'.format(name=name, suffix=suffix))
    # try to avoid setuptools if possible
    cc = os.environ.get("CC")
    if cc is None:
        clang = shutil.which("clang")
        gcc = shutil.which("gcc")
        cc = gcc if gcc is not None else clang
        if cc is None:
            raise RuntimeError(
                "Failed to find C compiler. Please specify via CC environment variable or set triton.knobs.build.impl.")
    # This function was renamed and made public in Python 3.10
    if hasattr(sysconfig, 'get_default_scheme'):
        scheme = sysconfig.get_default_scheme()
    else:
        scheme = sysconfig._get_default_scheme()  # type: ignore
    # 'posix_local' is a custom scheme on Debian. However, starting Python 3.10, the default install
    # path changes to include 'local'. This change is required to use triton with system-wide python.
    if scheme == 'posix_local':
        scheme = 'posix_prefix'
    py_include_dir = sysconfig.get_paths(scheme=scheme)["include"]
    custom_backend_dirs = knobs.build.backend_dirs
    include_dirs = include_dirs + [srcdir, py_include_dir, *custom_backend_dirs]
    # for -Wno-psabi, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111047
    cc_cmd = [cc, src, "-O3", "-shared", "-fPIC", "-Wno-psabi", "-o", so]
    cc_cmd += [f'-l{lib}' for lib in libraries]
    cc_cmd += [f"-L{dir}" for dir in library_dirs]
    cc_cmd += [f"-I{dir}" for dir in include_dirs if dir is not None]
    subprocess.check_call(cc_cmd, stdout=subprocess.DEVNULL)
    return so