# SPDX-License-Identifier: Apache-2.0
# DeepSpeed Team

import shutil
import subprocess

from .builder import SUPAOpBuilder


class AsyncIOBuilder(SUPAOpBuilder):
    BUILD_VAR = "DS_BUILD_AIO"
    NAME = "async_io"

    def __init__(self):
        super().__init__(name=self.NAME)

    def absolute_name(self):
        return f'deepspeed.ops.aio.{self.NAME}_op'

    def sources(self):
        return [
            'csrc/aio/py_lib/deepspeed_py_copy.cpp',
            'csrc/aio/py_lib/py_ds_aio.cpp',
            'csrc/aio/py_lib/deepspeed_py_aio.cpp',
            'csrc/aio/py_lib/deepspeed_py_aio_handle.cpp',
            'csrc/aio/py_lib/deepspeed_aio_thread.cpp',
            'csrc/aio/common/deepspeed_aio_utils.cpp',
            'csrc/aio/common/deepspeed_aio_common.cpp',
            'csrc/aio/common/deepspeed_aio_types.cpp',
            'csrc/aio/py_lib/deepspeed_pin_tensor.cpp',
            'csrc/aio/py_lib/deepspeed_py_io_handle.cpp',
            'csrc/aio/py_lib/deepspeed_cpu_op.cpp',
            'csrc/aio/py_lib/deepspeed_aio_op_desc.cpp',
        ]

    def include_paths(self):
        args = super().include_paths()
        args += ['csrc/aio/py_lib', 'csrc/aio/common']
        return args

    def cxx_args(self):
        args = super().cxx_args()
        # -O0 for improved debugging, since performance is bound by I/O
        return [a for a in args if not a.startswith('-O')] + ['-O0', '-Wall', '-shared', '-fPIC']

    def extra_ldflags(self):
        return ['-laio']

    def check_for_libaio_pkg(self):
        libs = dict(
            dpkg=["-l", "libaio-dev", "apt"],
            pacman=["-Q", "libaio", "pacman"],
            rpm=["-q", "libaio-devel", "yum"],
        )

        found = False
        for pkgmgr, data in libs.items():
            flag, lib, tool = data
            path = shutil.which(pkgmgr)
            if path is not None:
                cmd = [pkgmgr, flag, lib]
                result = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
                if result.wait() == 0:
                    found = True
                else:
                    self.warning(f"{self.NAME}: please install the {lib} package with {tool}")
                break
        return found

    def is_compatible(self, verbose=False):
        # Check for the existence of libaio by using distutils
        # to compile and link a test program that calls io_submit,
        # which is a function provided by libaio that is used in the async_io op.
        # If needed, one can define -I and -L entries in CFLAGS and LDFLAGS
        # respectively to specify the directories for libaio.h and libaio.so.
        aio_compatible = self.has_function('io_pgetevents', ('aio', ))
        if verbose and not aio_compatible:
            self.warning(f"{self.NAME} requires the dev libaio .so object and headers but these were not found.")

            # Check for the libaio package via known package managers
            # to print suggestions on which package to install.
            self.check_for_libaio_pkg()

            self.warning(
                "If libaio is already installed (perhaps from source), try setting the CFLAGS and LDFLAGS environment variables to where it can be found."
            )
        return super().is_compatible(verbose) and aio_compatible