# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
#
# 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.

import os
import six
import sys
import textwrap
import copy

import setuptools
from setuptools.command.easy_install import easy_install
from setuptools.command.build_ext import build_ext

from .extension_utils import find_cuda_home, normalize_extension_kwargs, add_compile_flag, bootstrap_context
from .extension_utils import is_cuda_file, prepare_unix_cflags, add_std_without_repeat, get_build_directory
from .extension_utils import _import_module_from_library, CustomOpInfo, _write_setup_file, _jit_compile, parse_op_name_from
from .extension_utils import check_abi_compatibility, log_v
from .extension_utils import use_new_custom_op_load_method

IS_WINDOWS = os.name == 'nt'
CUDA_HOME = find_cuda_home()


def setup(**attr):
    """
    Wrapper setuptools.setup function to valid `build_ext` command and
    implement paddle api code injection by switching `write_stub`
    function in bdist_egg with `custom_write_stub`.
    """
    cmdclass = attr.get('cmdclass', {})
    assert isinstance(cmdclass, dict)
    # if not specific cmdclass in setup, add it automaticaly.
    if 'build_ext' not in cmdclass:
        cmdclass['build_ext'] = BuildExtension.with_options(
            no_python_abi_suffix=True)
        attr['cmdclass'] = cmdclass

    # Add rename .so hook in easy_install
    assert 'easy_install' not in cmdclass
    cmdclass['easy_install'] = EasyInstallCommand

    # Always set zip_safe=False to make compatible in PY2 and PY3
    # See http://peak.telecommunity.com/DevCenter/setuptools#setting-the-zip-safe-flag
    attr['zip_safe'] = False

    # switch `write_stub` to inject paddle api in .egg
    with bootstrap_context():
        setuptools.setup(**attr)


def CppExtension(name, sources, *args, **kwargs):
    """
    Returns setuptools.CppExtension instance for setup.py to make it easy
    to specify compile flags while building C++ custommed op kernel.

    Args:
           name(str): The extension name used as generated shared library name
           sources(list[str]): The C++/CUDA source file names
           args(list[options]): list of config options used to compile shared library
           kwargs(dict[option]): dict of config options used to compile shared library
           
       Returns:
           Extension: An instance of setuptools.Extension
    """
    kwargs = normalize_extension_kwargs(kwargs, use_cuda=False)

    return setuptools.Extension(name, sources, *args, **kwargs)


def CUDAExtension(name, sources, *args, **kwargs):
    """
    Returns setuptools.CppExtension instance for setup.py to make it easy
    to specify compile flags while build CUDA custommed op kernel.

    Args:
           name(str): The extension name used as generated shared library name
           sources(list[str]): The C++/CUDA source file names
           args(list[options]): list of config options used to compile shared library
           kwargs(dict[option]): dict of config options used to compile shared library
           
       Returns:
           Extension: An instance of setuptools.Extension
    """
    kwargs = normalize_extension_kwargs(kwargs, use_cuda=True)

    return setuptools.Extension(name, sources, *args, **kwargs)


class BuildExtension(build_ext, object):
    """
    Inherited from setuptools.command.build_ext to customize how to apply
    compilation process with share library.
    """

    @classmethod
    def with_options(cls, **options):
        """
        Returns a BuildExtension subclass containing use-defined options.
        """

        class cls_with_options(cls):
            def __init__(self, *args, **kwargs):
                kwargs.update(options)
                cls.__init__(self, *args, **kwargs)

        return cls_with_options

    def __init__(self, *args, **kwargs):
        """
        Attributes is initialized with following oreder:
        
            1. super(self).__init__()
            2. initialize_options(self)
            3. the reset of current __init__()
            4. finalize_options(self)
        
        So, it is recommended to set attribute value in `finalize_options`.
        """
        super(BuildExtension, self).__init__(*args, **kwargs)
        self.no_python_abi_suffix = kwargs.get("no_python_abi_suffix", True)
        self.output_dir = kwargs.get("output_dir", None)
        # for compatible two custom op define method
        use_new_custom_op_load_method(
            kwargs.get("use_new_method", use_new_custom_op_load_method()))

    def initialize_options(self):
        super(BuildExtension, self).initialize_options()

    def finalize_options(self):
        super(BuildExtension, self).finalize_options()
        # NOTE(Aurelius84): Set location of compiled shared library.
        # Carefully to modify this because `setup.py build/install`
        # and `load` interface rely on this attribute.
        if self.output_dir is not None:
            self.build_lib = self.output_dir

    def build_extensions(self):
        self._check_abi()
        for extension in self.extensions:
            # check settings of compiler
            if isinstance(extension.extra_compile_args, dict):
                for compiler in ['cxx', 'nvcc']:
                    if compiler not in extension.extra_compile_args:
                        extension.extra_compile_args[compiler] = []
            # add determine compile flags
            add_compile_flag(extension, '-std=c++11')

        # Consider .cu, .cu.cc as valid source extensions.
        self.compiler.src_extensions += ['.cu', '.cu.cc']
        # Save the original _compile method for later.
        if self.compiler.compiler_type == 'msvc' or IS_WINDOWS:
            raise NotImplementedError("Not support on MSVC currently.")
        else:
            original_compile = self.compiler._compile

        def unix_custom_single_compiler(obj, src, ext, cc_args, extra_postargs,
                                        pp_opts):
            """
            Monkey patch machanism to replace inner compiler to custom complie process on Unix platform.
            """
            # use abspath to ensure no warning and don't remove deecopy because modify params
            # with dict type is dangerous.
            src = os.path.abspath(src)
            cflags = copy.deepcopy(extra_postargs)
            try:
                original_compiler = self.compiler.compiler_so
                # ncvv compile CUDA source
                if is_cuda_file(src):
                    assert CUDA_HOME is not None
                    nvcc_cmd = os.path.join(CUDA_HOME, 'bin', 'nvcc')
                    self.compiler.set_executable('compiler_so', nvcc_cmd)
                    # {'nvcc': {}, 'cxx: {}}
                    if isinstance(cflags, dict):
                        cflags = cflags['nvcc']
                    else:
                        cflags = prepare_unix_cflags(cflags)
                # cxx compile Cpp source
                elif isinstance(cflags, dict):
                    cflags = cflags['cxx']

                add_std_without_repeat(
                    cflags, self.compiler.compiler_type, use_std14=False)
                original_compile(obj, src, ext, cc_args, cflags, pp_opts)
            finally:
                # restore original_compiler
                self.compiler.compiler_so = original_compiler

        def object_filenames_with_cuda(origina_func, build_directory):
            """
            Decorated the function to add customized naming machanism.
            Originally, both .cc/.cu will have .o object output that will
            bring file override problem. Use .cu.o as CUDA object suffix.
            """

            def wrapper(source_filenames, strip_dir=0, output_dir=''):
                try:
                    objects = origina_func(source_filenames, strip_dir,
                                           output_dir)
                    for i, source in enumerate(source_filenames):
                        # modify xx.o -> xx.cu.o
                        if is_cuda_file(source):
                            old_obj = objects[i]
                            objects[i] = old_obj[:-1] + 'cu.o'
                    # if user set build_directory, output objects there.
                    if build_directory is not None:
                        objects = [
                            os.path.join(build_directory, os.path.basename(obj))
                            for obj in objects
                        ]
                    # ensure to use abspath
                    objects = [os.path.abspath(obj) for obj in objects]
                finally:
                    self.compiler.object_filenames = origina_func

                return objects

            return wrapper

        # customized compile process
        self.compiler._compile = unix_custom_single_compiler
        self.compiler.object_filenames = object_filenames_with_cuda(
            self.compiler.object_filenames, self.build_lib)

        self._record_op_info()

        print("Compiling user custom op, it will cost a few seconds.....")
        build_ext.build_extensions(self)

    def get_ext_filename(self, fullname):
        # for example: custommed_extension.cpython-37m-x86_64-linux-gnu.so
        ext_name = super(BuildExtension, self).get_ext_filename(fullname)
        if self.no_python_abi_suffix and six.PY3:
            split_str = '.'
            name_items = ext_name.split(split_str)
            assert len(
                name_items
            ) > 2, "Expected len(name_items) > 2, but received {}".format(
                len(name_items))
            name_items.pop(-2)
            # custommed_extension.so
            ext_name = split_str.join(name_items)

        return ext_name

    def _check_abi(self):
        """
        Check ABI Compatibility.
        """
        if hasattr(self.compiler, 'compiler_cxx'):
            compiler = self.compiler.compiler_cxx[0]
        elif IS_WINDOWS:
            compiler = os.environ.get('CXX', 'cl')
            raise NotImplementedError("We don't support Windows Currently.")
        else:
            compiler = os.environ.get('CXX', 'c++')

        check_abi_compatibility(compiler)

    def _record_op_info(self):
        """
        Record custum op inforomation. 
        """
        # parse op name
        sources = []
        for extension in self.extensions:
            sources.extend(extension.sources)

        sources = [os.path.abspath(s) for s in sources]
        op_name = parse_op_name_from(sources)

        # parse shared library abs path
        outputs = self.get_outputs()
        assert len(outputs) == 1

        build_directory = os.path.abspath(outputs[0])
        so_name = os.path.basename(build_directory)
        CustomOpInfo.instance().add(op_name,
                                    so_name=so_name,
                                    build_directory=build_directory)


class EasyInstallCommand(easy_install, object):
    """
    Extend easy_intall Command to control the behavior of naming shared library
    file.

    NOTE(Aurelius84): This is a hook subclass inherited Command used to rename shared
                    library file after extracting egg-info into site-packages.
    """

    def __init__(self, *args, **kwargs):
        super(EasyInstallCommand, self).__init__(*args, **kwargs)

    # NOTE(Aurelius84): Add args and kwargs to make compatible with PY2/PY3
    def run(self, *args, **kwargs):
        super(EasyInstallCommand, self).run(*args, **kwargs)
        # NOTE: To avoid failing import .so file instead of
        # python file because they have same name, we rename
        # .so shared library to another name.
        for egg_file in self.outputs:
            filename, ext = os.path.splitext(egg_file)
            if ext == '.so':
                new_so_path = filename + "_pd_" + ext
                if not os.path.exists(new_so_path):
                    os.rename(r'%s' % egg_file, r'%s' % new_so_path)
                assert os.path.exists(new_so_path)


def load(name,
         sources,
         extra_cflags=None,
         extra_cuda_cflags=None,
         extra_ldflags=None,
         extra_include_paths=None,
         build_directory=None,
         interpreter=None,
         verbose=False):
    """
    An Interface to automatically compile C++/CUDA source files Just-In-Time
    and return callable python function as other Paddle layers API. It will
    append user defined custom op in background.

    This module will perform compiling, linking, api generation and module loading
    processes for users. It does not require CMake or Ninja environment and only
    g++/nvcc on Linux and clang++ on MacOS. Moreover, ABI compatibility will be
    checked to ensure that compiler version on local machine is compatible with
    pre-installed Paddle whl in python site-packages. For example if Paddle is built
    with GCC5.4, the version of user's local machine should satisfy GCC >= 5.4.
    Otherwise, a fatal error will occur because  ABI compatibility.

    Args:
        name(str): generated shared library file name.
        sources(list[str]): custom op source files name with .cc/.cu suffix.
        extra_cflag(list[str]): additional flags used to compile CPP files. By default
                               all basic and framework related flags have been included.
                               If your pre-insall Paddle supported MKLDNN, please add
                               '-DPADDLE_WITH_MKLDNN'. Default None.
        extra_cuda_cflags(list[str]): additonal flags used to compile CUDA files. See
                                https://docs.nvidia.com/cuda/cuda-compiler-driver-nvcc/index.html
                                for details. Default None.
        extra_ldflags(list[str]): additonal flags used to link shared library. See
                                https://gcc.gnu.org/onlinedocs/gcc/Link-Options.html for details.
                                Default None.
        extra_include_paths(list[str]): additional include path used to search header files.
                                        Default None.
        build_directory(str): specific directory path to put shared library file. If set None,
                            it will use `PADDLE_EXTENSION_DIR` from os.environ. Use 
                            `paddle.utils.cpp_extension.get_build_directory()` to see the location.
        interpreter(str): alias or full interpreter path to specific which one to use if have installed multiple.
                           If set None, will use `python` as default interpreter.
        verbose(bool): whether to verbose compiled log information

    Returns:
        custom api: A callable python function with same signature as CustomOp Kernel defination.

    Example:

        >> from paddle.utils.cpp_extension import load
        >> relu2 = load(name='relu2',
                        sources=['relu_op.cc', 'relu_op.cu'])
        >> x = paddle.rand([4, 10]], dtype='float32')
        >> out = relu2(x)
    """

    if build_directory is None:
        build_directory = get_build_directory(verbose)

    # ensure to use abs path
    build_directory = os.path.abspath(build_directory)
    log_v("build_directory: {}".format(build_directory), verbose)

    file_path = os.path.join(build_directory, "setup.py")
    sources = [os.path.abspath(source) for source in sources]

    # TODO(Aurelius84): split cflags and cuda_flags
    if extra_cflags is None: extra_cflags = []
    if extra_cuda_cflags is None: extra_cuda_cflags = []
    compile_flags = extra_cflags + extra_cuda_cflags
    log_v("additonal compile_flags: [{}]".format(' '.join(compile_flags)),
          verbose)

    # write setup.py file and compile it 
    _write_setup_file(name, sources, file_path, extra_include_paths,
                      compile_flags, extra_ldflags, verbose)
    _jit_compile(file_path, interpreter, verbose)

    # import as callable python api
    custom_op_api = _import_module_from_library(name, build_directory, verbose)

    return custom_op_api
