# Copyright 2015 gRPC authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Provides distutils command classes for the GRPC Python setup process."""

# NOTE(https://github.com/grpc/grpc/issues/24028): allow setuptools to monkey
# patch distutils
import setuptools  # isort:skip

import glob
import os
import os.path
import shutil
import subprocess
import sys
import sysconfig
import traceback

from setuptools.command import build_ext
from setuptools.command import build_py
import support

PYTHON_STEM = os.path.dirname(os.path.abspath(__file__))
GRPC_STEM = os.path.abspath(PYTHON_STEM + '../../../../')
PROTO_STEM = os.path.join(GRPC_STEM, 'src', 'proto')
PROTO_GEN_STEM = os.path.join(GRPC_STEM, 'src', 'python', 'gens')
CYTHON_STEM = os.path.join(PYTHON_STEM, 'grpc', '_cython')


class CommandError(Exception):
    """Simple exception class for GRPC custom commands."""


# TODO(atash): Remove this once PyPI has better Linux bdist support. See
# https://bitbucket.org/pypa/pypi/issues/120/binary-wheels-for-linux-are-not-supported
def _get_grpc_custom_bdist(decorated_basename, target_bdist_basename):
    """Returns a string path to a bdist file for Linux to install.

  If we can retrieve a pre-compiled bdist from online, uses it. Else, emits a
  warning and builds from source.
  """
    # TODO(atash): somehow the name that's returned from `wheel` is different
    # between different versions of 'wheel' (but from a compatibility standpoint,
    # the names are compatible); we should have some way of determining name
    # compatibility in the same way `wheel` does to avoid having to rename all of
    # the custom wheels that we build/upload to GCS.

    # Break import style to ensure that setup.py has had a chance to install the
    # relevant package.
    from urllib import request
    decorated_path = decorated_basename + GRPC_CUSTOM_BDIST_EXT
    try:
        url = BINARIES_REPOSITORY + '/{target}'.format(target=decorated_path)
        bdist_data = request.urlopen(url).read()
    except IOError as error:
        raise CommandError('{}\n\nCould not find the bdist {}: {}'.format(
            traceback.format_exc(), decorated_path, error.message))
    # Our chosen local bdist path.
    bdist_path = target_bdist_basename + GRPC_CUSTOM_BDIST_EXT
    try:
        with open(bdist_path, 'w') as bdist_file:
            bdist_file.write(bdist_data)
    except IOError as error:
        raise CommandError('{}\n\nCould not write grpcio bdist: {}'.format(
            traceback.format_exc(), error.message))
    return bdist_path


class SphinxDocumentation(setuptools.Command):
    """Command to generate documentation via sphinx."""

    description = 'generate sphinx documentation'
    user_options = []

    def initialize_options(self):
        pass

    def finalize_options(self):
        pass

    def run(self):
        # We import here to ensure that setup.py has had a chance to install the
        # relevant package eggs first.
        import sphinx.cmd.build
        source_dir = os.path.join(GRPC_STEM, 'doc', 'python', 'sphinx')
        target_dir = os.path.join(GRPC_STEM, 'doc', 'build')
        exit_code = sphinx.cmd.build.build_main(
            ['-b', 'html', '-W', '--keep-going', source_dir, target_dir])
        if exit_code != 0:
            raise CommandError(
                "Documentation generation has warnings or errors")


class BuildProjectMetadata(setuptools.Command):
    """Command to generate project metadata in a module."""

    description = 'build grpcio project metadata files'
    user_options = []

    def initialize_options(self):
        pass

    def finalize_options(self):
        pass

    def run(self):
        with open(os.path.join(PYTHON_STEM, 'grpc/_grpcio_metadata.py'),
                  'w') as module_file:
            module_file.write('__version__ = """{}"""'.format(
                self.distribution.get_version()))


class BuildPy(build_py.build_py):
    """Custom project build command."""

    def run(self):
        self.run_command('build_project_metadata')
        build_py.build_py.run(self)


def _poison_extensions(extensions, message):
    """Includes a file that will always fail to compile in all extensions."""
    poison_filename = os.path.join(PYTHON_STEM, 'poison.c')
    with open(poison_filename, 'w') as poison:
        poison.write('#error {}'.format(message))
    for extension in extensions:
        extension.sources = [poison_filename]


def check_and_update_cythonization(extensions):
    """Replace .pyx files with their generated counterparts and return whether or
     not cythonization still needs to occur."""
    for extension in extensions:
        generated_pyx_sources = []
        other_sources = []
        for source in extension.sources:
            base, file_ext = os.path.splitext(source)
            if file_ext == '.pyx':
                generated_pyx_source = next((base + gen_ext for gen_ext in (
                    '.c',
                    '.cpp',
                ) if os.path.isfile(base + gen_ext)), None)
                if generated_pyx_source:
                    generated_pyx_sources.append(generated_pyx_source)
                else:
                    sys.stderr.write('Cython-generated files are missing...\n')
                    return False
            else:
                other_sources.append(source)
        extension.sources = generated_pyx_sources + other_sources
    sys.stderr.write('Found cython-generated files...\n')
    return True


def try_cythonize(extensions, linetracing=False, mandatory=True):
    """Attempt to cythonize the extensions.

  Args:
    extensions: A list of `distutils.extension.Extension`.
    linetracing: A bool indicating whether or not to enable linetracing.
    mandatory: Whether or not having Cython-generated files is mandatory. If it
      is, extensions will be poisoned when they can't be fully generated.
  """
    try:
        # Break import style to ensure we have access to Cython post-setup_requires
        import Cython.Build
    except ImportError:
        if mandatory:
            sys.stderr.write(
                "This package needs to generate C files with Cython but it cannot. "
                "Poisoning extension sources to disallow extension commands...")
            _poison_extensions(
                extensions,
                "Extensions have been poisoned due to missing Cython-generated code."
            )
        return extensions
    cython_compiler_directives = {}
    if linetracing:
        additional_define_macros = [('CYTHON_TRACE_NOGIL', '1')]
        cython_compiler_directives['linetrace'] = True
    return Cython.Build.cythonize(
        extensions,
        include_path=[
            include_dir for extension in extensions
            for include_dir in extension.include_dirs
        ] + [CYTHON_STEM],
        compiler_directives=cython_compiler_directives)


class BuildExt(build_ext.build_ext):
    """Custom build_ext command to enable compiler-specific flags."""

    C_OPTIONS = {
        'unix': ('-pthread',),
        'msvc': (),
    }
    LINK_OPTIONS = {}

    def get_ext_filename(self, ext_name):
        # since python3.5, python extensions' shared libraries use a suffix that corresponds to the value
        # of sysconfig.get_config_var('EXT_SUFFIX') and contains info about the architecture the library targets.
        # E.g. on x64 linux the suffix is ".cpython-XYZ-x86_64-linux-gnu.so"
        # When crosscompiling python wheels, we need to be able to override this suffix
        # so that the resulting file name matches the target architecture and we end up with a well-formed
        # wheel.
        filename = build_ext.build_ext.get_ext_filename(self, ext_name)
        orig_ext_suffix = sysconfig.get_config_var('EXT_SUFFIX')
        new_ext_suffix = os.getenv('GRPC_PYTHON_OVERRIDE_EXT_SUFFIX')
        if new_ext_suffix and filename.endswith(orig_ext_suffix):
            filename = filename[:-len(orig_ext_suffix)] + new_ext_suffix
        return filename

    def build_extensions(self):

        def compiler_ok_with_extra_std():
            """Test if default compiler is okay with specifying c++ version
            when invoked in C mode. GCC is okay with this, while clang is not.
            """
            try:
                # TODO(lidiz) Remove the generated a.out for success tests.
                cc = os.environ.get('CC', 'cc')
                cc_test = subprocess.Popen([cc, '-x', 'c', '-std=c++14', '-'],
                                           stdin=subprocess.PIPE,
                                           stdout=subprocess.PIPE,
                                           stderr=subprocess.PIPE)
                _, cc_err = cc_test.communicate(input=b'int main(){return 0;}')
                return not 'invalid argument' in str(cc_err)
            except:
                sys.stderr.write('Non-fatal exception:' +
                                 traceback.format_exc() + '\n')
                return False

        # This special conditioning is here due to difference of compiler
        #   behavior in gcc and clang. The clang doesn't take --stdc++11
        #   flags but gcc does. Since the setuptools of Python only support
        #   all C or all C++ compilation, the mix of C and C++ will crash.
        #   *By default*, macOS and FreBSD use clang and Linux use gcc
        #
        #   If we are not using a permissive compiler that's OK with being
        #   passed wrong std flags, swap out compile function by adding a filter
        #   for it.
        if not compiler_ok_with_extra_std():
            old_compile = self.compiler._compile

            def new_compile(obj, src, ext, cc_args, extra_postargs, pp_opts):
                if src.endswith('.c'):
                    extra_postargs = [
                        arg for arg in extra_postargs if not '-std=c++' in arg
                    ]
                elif src.endswith('.cc') or src.endswith('.cpp'):
                    extra_postargs = [
                        arg for arg in extra_postargs if not '-std=gnu99' in arg
                    ]
                return old_compile(obj, src, ext, cc_args, extra_postargs,
                                   pp_opts)

            self.compiler._compile = new_compile

        compiler = self.compiler.compiler_type
        if compiler in BuildExt.C_OPTIONS:
            for extension in self.extensions:
                extension.extra_compile_args += list(
                    BuildExt.C_OPTIONS[compiler])
        if compiler in BuildExt.LINK_OPTIONS:
            for extension in self.extensions:
                extension.extra_link_args += list(
                    BuildExt.LINK_OPTIONS[compiler])
        if not check_and_update_cythonization(self.extensions):
            self.extensions = try_cythonize(self.extensions)
        try:
            build_ext.build_ext.build_extensions(self)
        except Exception as error:
            formatted_exception = traceback.format_exc()
            support.diagnose_build_ext_error(self, error, formatted_exception)
            raise CommandError(
                "Failed `build_ext` step:\n{}".format(formatted_exception))


class Gather(setuptools.Command):
    """Command to gather project dependencies."""

    description = 'gather dependencies for grpcio'
    user_options = [
        ('test', 't', 'flag indicating to gather test dependencies'),
        ('install', 'i', 'flag indicating to gather install dependencies')
    ]

    def initialize_options(self):
        self.test = False
        self.install = False

    def finalize_options(self):
        # distutils requires this override.
        pass

    def run(self):
        if self.install and self.distribution.install_requires:
            self.distribution.fetch_build_eggs(
                self.distribution.install_requires)
        if self.test and self.distribution.tests_require:
            self.distribution.fetch_build_eggs(self.distribution.tests_require)


class Clean(setuptools.Command):
    """Command to clean build artifacts."""

    description = 'Clean build artifacts.'
    user_options = [
        ('all', 'a', 'a phony flag to allow our script to continue'),
    ]

    _FILE_PATTERNS = (
        'python_build',
        'src/python/grpcio/__pycache__/',
        'src/python/grpcio/grpc/_cython/cygrpc.cpp',
        'src/python/grpcio/grpc/_cython/*.so',
        'src/python/grpcio/grpcio.egg-info/',
    )
    _CURRENT_DIRECTORY = os.path.normpath(
        os.path.join(os.path.dirname(os.path.realpath(__file__)), "../../.."))

    def initialize_options(self):
        self.all = False

    def finalize_options(self):
        pass

    def run(self):
        for path_spec in self._FILE_PATTERNS:
            this_glob = os.path.normpath(
                os.path.join(Clean._CURRENT_DIRECTORY, path_spec))
            abs_paths = glob.glob(this_glob)
            for path in abs_paths:
                if not str(path).startswith(Clean._CURRENT_DIRECTORY):
                    raise ValueError(
                        "Cowardly refusing to delete {}.".format(path))
                print("Removing {}".format(os.path.relpath(path)))
                if os.path.isfile(path):
                    os.remove(str(path))
                else:
                    shutil.rmtree(str(path))
