import logging
import os
from shutil import which, move
import subprocess
import sys
import sysconfig
from pathlib import Path

from setuptools import Extension, find_packages, setup
from setuptools.command.build_ext import build_ext

logger = logging.getLogger(__name__)


def get_backend() -> str:
    if which("nvcc") is not None:
        return "cuda"
    return "cpu"


backend = get_backend()
ops_name = f"_{{ kernel_name }}_{backend}_{{ kernel_unique_id }}"


def is_sccache_available() -> bool:
    return which("sccache") is not None


def is_ccache_available() -> bool:
    return which("ccache") is not None


def is_ninja_available() -> bool:
    return which("ninja") is not None


class CMakeExtension(Extension):
    def __init__(self, name: str, sourcedir: str = "") -> None:
        super().__init__(name, sources=[], py_limited_api=False)
        self.sourcedir = os.fspath(Path(sourcedir).resolve())


class CMakeBuild(build_ext):
    def build_extension(self, ext: CMakeExtension) -> None:
        ext_fullpath = Path.cwd() / self.get_ext_fullpath(ext.name)
        extdir = ext_fullpath.parent.resolve()

        debug = int(os.environ.get("DEBUG", 0)) if self.debug is None else self.debug
        cfg = "Debug" if debug else "Release"

        cmake_generator = os.environ.get("CMAKE_GENERATOR", "")

        # Set Python3_EXECUTABLE instead if you use PYBIND11_FINDPYTHON
        # EXAMPLE_VERSION_INFO shows you how to pass a value into the C++ code
        # from Python.
        cmake_args = [
            f"-DCMAKE_LIBRARY_OUTPUT_DIRECTORY={extdir}{os.sep}",
            f"-DPython3_EXECUTABLE={sys.executable}",
            f"-DCMAKE_BUILD_TYPE={cfg}",  # not used on MSVC, but no harm
        ]
        build_args = []
        if "CMAKE_ARGS" in os.environ:
            cmake_args += [item for item in os.environ["CMAKE_ARGS"].split(" ") if item]

        if not cmake_generator or cmake_generator == "Ninja":
            try:
                import ninja

                ninja_executable_path = Path(ninja.BIN_DIR) / "ninja"
                cmake_args += [
                    "-GNinja",
                    f"-DCMAKE_MAKE_PROGRAM:FILEPATH={ninja_executable_path}",
                ]
            except ImportError:
                pass

        if is_sccache_available():
            cmake_args += [
                "-DCMAKE_C_COMPILER_LAUNCHER=sccache",
                "-DCMAKE_CXX_COMPILER_LAUNCHER=sccache",
                "-DCMAKE_CUDA_COMPILER_LAUNCHER=sccache",
                "-DCMAKE_HIP_COMPILER_LAUNCHER=sccache",
                "-DCMAKE_OBJC_COMPILER_LAUNCHER=sccache",
                "-DCMAKE_OBJCXX_COMPILER_LAUNCHER=sccache",
            ]
        elif is_ccache_available():
            cmake_args += [
                "-DCMAKE_C_COMPILER_LAUNCHER=ccache",
                "-DCMAKE_CXX_COMPILER_LAUNCHER=ccache",
                "-DCMAKE_CUDA_COMPILER_LAUNCHER=ccache",
                "-DCMAKE_HIP_COMPILER_LAUNCHER=ccache",
                "-DCMAKE_OBJC_COMPILER_LAUNCHER=ccache",
                "-DCMAKE_OBJCXX_COMPILER_LAUNCHER=ccache",
            ]

        num_jobs = os.getenv("MAX_JOBS", None)
        if num_jobs is not None:
            num_jobs = int(num_jobs)
            logger.info("Using MAX_JOBS=%d as the number of jobs.", num_jobs)
        else:
            try:
                # os.sched_getaffinity() isn't universally available, so fall
                #  back to os.cpu_count() if we get an error here.
                num_jobs = len(os.sched_getaffinity(0))
            except AttributeError:
                num_jobs = os.cpu_count()

        nvcc_threads = os.getenv("NVCC_THREADS", None)
        if nvcc_threads is not None:
            nvcc_threads = int(nvcc_threads)
            logger.info(
                "Using NVCC_THREADS=%d as the number of nvcc threads.", nvcc_threads
            )
            num_jobs = max(1, num_jobs // nvcc_threads)
            cmake_args += ["-DNVCC_THREADS={}".format(nvcc_threads)]

        build_args += [f"-j{num_jobs}"]
        if sys.platform == "win32":
            build_args += ["--config", cfg]

        build_temp = Path(self.build_temp) / ext.name
        if not build_temp.exists():
            build_temp.mkdir(parents=True)

        subprocess.run(
            ["cmake", ext.sourcedir, *cmake_args], cwd=build_temp, check=True
        )
        subprocess.run(
            ["cmake", "--build", ".", *build_args], cwd=build_temp, check=True
        )

        if sys.platform == "win32":
            # Move the dylib one folder up for discovery.
            for filename in os.listdir(extdir / cfg):
                move(extdir / cfg / filename, extdir / filename)

    def get_ext_filename(self, ext_name):
        # The dynamic library is not a real Python extension, so it does not have
        # the usual Python platform information.
        suffix = sysconfig.get_config_var("SHLIB_SUFFIX")
        return f"{ext_name.replace(".", "/")}/{ops_name}{suffix}"

setup(
    name="{{ python_name }}",
    # The version is just a stub, it's not used by the final build artefact.
    version="0.1.0",
    ext_modules=[CMakeExtension(f"{{ python_name }}.{ops_name}")],
    cmdclass={"build_ext": CMakeBuild},
    packages=find_packages(where="tvm-ffi-ext", include=["{{ python_name }}*"]),
    package_dir={"": "tvm-ffi-ext"},
{% if data_globs %}
    package_data={"{{ python_name }}": [ {{ data_globs }} ]},
{% endif %}
    zip_safe=False,
    install_requires=["tvm-ffi"],
    python_requires=">=3.9",
)
