import os
import re
import subprocess
import sys
from pathlib import Path

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

# Convert distutils Windows platform specifiers to CMake -A arguments
PLAT_TO_CMAKE = {
    "win32": "Win32",
    "win-amd64": "x64",
    "win-arm32": "ARM",
    "win-arm64": "ARM64",
}


# A CMakeExtension needs a sourcedir instead of a file list.
# The name must be the _single_ output extension from the CMake build.
# If you need multiple extensions, see scikit-build.
class CMakeExtension(Extension):
    def __init__(self, name: str, sourcedir: str = "") -> None:
        super().__init__(name, sources=[])
        self.sourcedir = os.fspath(Path(sourcedir).resolve())


class CMakeBuild(build_ext):
    def build_extension(self, ext: CMakeExtension) -> None:
        # Must be in this form due to bug in .resolve() only fixed in Python 3.10+
        ext_fullpath = Path.cwd() / self.get_ext_fullpath(ext.name)
        extdir = ext_fullpath.parent.resolve()

        # Using this requires trailing slash for auto-detection & inclusion of
        # auxiliary "native" libs

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

        # CMake lets you override the generator - we need to check this.
        # Can be set with Conda-Build, for example.
        cmake_generator = os.environ.get("CMAKE_GENERATOR", "")

        # Set Python_EXECUTABLE instead if you use PYBIND11_FINDPYTHON
        # CUALGO_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"-DPYTHON_EXECUTABLE={sys.executable}",
            f"-DCMAKE_BUILD_TYPE={cfg}",  # not used on MSVC, but no harm
        ]
        build_args = []
        # Adding CMake arguments set as environment variable
        # (needed e.g. to build for ARM OSx on conda-forge)
        if "CMAKE_ARGS" in os.environ:
            cmake_args += [item for item in os.environ["CMAKE_ARGS"].split(" ") if item]
        cmake_args += [f"-DCUALGO_VERSION_INFO={self.distribution.get_version()}"]

        if self.compiler.compiler_type != "msvc":
            # Using Ninja-build since it a) is available as a wheel and b)
            # multithreads automatically. MSVC would require all variables be
            # exported for Ninja to pick it up, which is a little tricky to do.
            # Users can override the generator with CMAKE_GENERATOR in CMake
            # 3.15+.
            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

        else:
            # Single config generators are handled "normally"
            single_config = any(x in cmake_generator for x in {"NMake", "Ninja"})

            # CMake allows an arch-in-generator style for backward compatibility
            contains_arch = any(x in cmake_generator for x in {"ARM", "Win64"})

            # Specify the arch if using MSVC generator, but only if it doesn't
            # contain a backward-compatibility arch spec already in the
            # generator name.
            if not single_config and not contains_arch:
                cmake_args += ["-A", PLAT_TO_CMAKE[self.plat_name]]

            # Multi-config generators have a different way to specify configs
            if not single_config:
                cmake_args += [
                    f"-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_{cfg.upper()}={extdir}"
                ]
                build_args += ["--config", cfg]

        if sys.platform.startswith("darwin"):
            # Cross-compile support for macOS - respect ARCHFLAGS if set
            archs = re.findall(r"-arch (\S+)", os.environ.get("ARCHFLAGS", ""))
            if archs:
                cmake_args += ["-DCMAKE_OSX_ARCHITECTURES={}".format(";".join(archs))]

        # Set CMAKE_BUILD_PARALLEL_LEVEL to control the parallel build level
        # across all generators.
        if "CMAKE_BUILD_PARALLEL_LEVEL" not in os.environ:
            # self.parallel is a Python 3 only way to set parallel jobs by hand
            # using -j in the build_ext call, not supported by pip or PyPA-build.
            if hasattr(self, "parallel") and self.parallel:
                # CMake 3.12+ only.
                build_args += [f"-j{self.parallel}"]

        build_temp = Path(self.build_temp) / ext.name
        if not build_temp.exists():
            build_temp.mkdir(parents=True)
        #find cmake from python package
        cmake = find_cmake()
        if sys.platform != 'win32':
            #find c++ compiler
            if not shutil.which('gcc'): #clang doesn't work with nvcc for now.
                raise FileNotFoundError('"gcc" not found')
            if not shutil.which('g++'):
                raise FileNotFoundError('"g++" not found')
            if not shutil.which('make'):
                raise FileNotFoundError('"make" not found')
        else:
            pass #For Windows: let cmake decide.. TODO: make it better
        
        #find pybind11
        import pybind11            
        cmake_args += [f'-Dpybind11_DIR={pybind11.get_cmake_dir()}']
        subprocess.run(
            [cmake, ext.sourcedir, *cmake_args], cwd=build_temp, check=True
        )
        subprocess.run(
            [cmake, "--build", ".", *build_args], cwd=build_temp, check=True
        )

def find_cmake():
    cmake_path = shutil.which('cmake')
    if not cmake_path:
        import cmake
        executable = next((name for name in os.listdir(cmake.CMAKE_BIN_DIR) if name == 'cmake' or name.lower() == 'cmake.exe'), None)
        if not executable:
            raise FileNotFoundError('"cmake" not found')
        cmake_path = os.fspath(Path(cmake.CMAKE_BIN_DIR) / executable)
    return cmake_path

extras_require = {
    'test': [
        # 4.2 <= pytest < 6.2 is slow collecting tests and times out on CI.
        'pytest>=7.2',
        'numpy',
    ],
}
setup(
    name = 'cualgo',
    version = '0.2.0',
    license='MIT',
    description = 'A Pytnon library containing basic algorithm with GPU-accelerated computing.',
    long_description=(Path(__file__).parent  / "README.md").read_text(),
    long_description_content_type='text/markdown',
    author = 'Anderson Meng',
    author_email = 'andersonchi1018@gmail.com',
    url = 'https://github.com/anderson101866/cualgo',
    download_url = 'https://github.com/anderson101866/cualgo/archive/refs/tags/v0.2.0.tar.gz',
    keywords = ['python', 'cuda', 'gpu', 'algorithm', 'numpy'],
    classifiers=[
    'Development Status :: 4 - Beta',
    'Intended Audience :: Developers', 
    'Intended Audience :: Education',
    'Intended Audience :: Science/Research',
    'Topic :: Software Development :: Libraries',
    'Topic :: Software Development :: Libraries :: Python Modules',
    'Topic :: Software Development :: Libraries',
    'License :: OSI Approved :: MIT License',
    'Programming Language :: Python :: 3',
    'Programming Language :: Python :: 3 :: Only',
    'Programming Language :: Python :: 3.7',
    'Programming Language :: Python :: 3.8',
    'Programming Language :: Python :: 3.9',
    'Programming Language :: Python :: 3.10',
    'Programming Language :: Python :: 3.11',
    'Programming Language :: Python :: 3.12',
    'Programming Language :: Python :: Implementation :: CPython',
    'Programming Language :: C++',
    'Environment :: GPU :: NVIDIA CUDA',
    ],
    ext_modules=[CMakeExtension("cualgo")],
    cmdclass={"build_ext": CMakeBuild},
    zip_safe=False,
    python_requires=">=3.7",
    setup_requires=['cmake >= 3.9', 'wheel', 'pybind11'],
    extras_require = extras_require,
)
