#!/usr/bin/env python

# Copyright (c) 2017-present, Facebook, Inc.
# All rights reserved.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
#

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals

from setuptools import setup, Extension
from setuptools.command.build_ext import build_ext
import sys
import setuptools
import os
import subprocess
import platform

FASTTEXT_SRC = "src"

# Based on https://github.com/pybind/python_example


class get_pybind_include:
    """Helper class to determine the pybind11 include path

    The purpose of this class is to postpone importing pybind11
    until it is actually installed, so that the ``get_include()``
    method can be invoked."""

    def __init__(self, user=False):
        try:
            pass
        except ImportError:
            if subprocess.call([sys.executable, "-m", "pip", "install", "pybind11"]):
                raise RuntimeError("pybind11 install failed.")

        self.user = user

    def __str__(self):
        import pybind11

        return pybind11.get_include(self.user)


try:
    coverage_index = sys.argv.index("--coverage")
except ValueError:
    coverage = False
else:
    del sys.argv[coverage_index]
    coverage = True

fasttext_src_files = map(str, os.listdir(FASTTEXT_SRC))
fasttext_src_cc = list(filter(lambda x: x.endswith(".cc"), fasttext_src_files))

fasttext_src_cc = list(
    map(lambda x: str(os.path.join(FASTTEXT_SRC, x)), fasttext_src_cc)
)

ext_modules = [
    Extension(
        str("fasttext_pybind"),
        [
            str("python/fasttext_module/fasttext/pybind/fasttext_pybind.cc"),
        ]
        + fasttext_src_cc,
        include_dirs=[
            # Path to pybind11 headers
            get_pybind_include(),
            get_pybind_include(user=True),
            # Path to fasttext source code
            FASTTEXT_SRC,
        ],
        language="c++",
    ),
]


# As of Python 3.6, CCompiler has a `has_flag` method.
# cf http://bugs.python.org/issue26689
def has_flag(compiler, flags):
    """Return a boolean indicating whether a flag name is supported on
    the specified compiler.
    """
    import tempfile

    with tempfile.NamedTemporaryFile("w", suffix=".cpp") as f:
        f.write("int main (int argc, char **argv) { return 0; }")
        try:
            compiler.compile([f.name], extra_postargs=flags)
        except setuptools.distutils.errors.CompileError:
            return False
    return True


def cpp_flag(compiler):
    """Return the -std=c++17 compiler flag."""
    standards = ["-std=c++17"]
    for standard in standards:
        if has_flag(compiler, [standard]):
            return standard
    raise RuntimeError("Unsupported compiler -- at least C++17 support " "is needed!")


class BuildExt(build_ext):
    """A custom build extension for adding compiler-specific options."""

    c_opts = {
        "msvc": ["/EHsc", "/O2"],
        "unix": ["-O3", "-funroll-loops", "-pthread"],
    }

    def build_extensions(self):
        if sys.platform == "darwin":
            # Only set if not already provided by the environment (CI/User)
            if "MACOSX_DEPLOYMENT_TARGET" not in os.environ:
                mac_osx_version = ".".join(platform.mac_ver()[0].split(".")[:2])
                os.environ["MACOSX_DEPLOYMENT_TARGET"] = mac_osx_version
            all_flags = ["-stdlib=libc++", "-mmacosx-version-min=10.7"]
            if has_flag(self.compiler, [all_flags[0]]):
                self.c_opts["unix"] += [all_flags[0]]
            elif has_flag(self.compiler, all_flags):
                self.c_opts["unix"] += all_flags
            else:
                raise RuntimeError(
                    "libc++ is needed! Failed to compile with {} and {}.".format(
                        " ".join(all_flags), all_flags[0]
                    )
                )
        ct = self.compiler.compiler_type
        opts = self.c_opts.get(ct, [])
        extra_link_args = []

        if coverage:
            opts = [o for o in opts if o not in ("-O3", "-funroll-loops")]
            opts += ["-O0", "-fno-inline", "-fprofile-arcs"]
            coverage_option = "--coverage"
            opts.append(coverage_option)
            extra_link_args.append(coverage_option)

        if ct == "unix":
            opts.append('-DVERSION_INFO="%s"' % self.distribution.get_version())
            opts.append(cpp_flag(self.compiler))
            if has_flag(self.compiler, ["-fvisibility=hidden"]):
                opts.append("-fvisibility=hidden")
        elif ct == "msvc":
            opts.append('/DVERSION_INFO=\\"%s\\"' % self.distribution.get_version())
            opts.append("/std:c++17")
        for ext in self.extensions:
            ext.extra_compile_args = opts
            ext.extra_link_args = extra_link_args
        build_ext.build_extensions(self)


setup(
    ext_modules=ext_modules,
    cmdclass={"build_ext": BuildExt},
)
