// Copyright  © 2024 Apple Inc.

#include <nanobind/nanobind.h>
#include <nanobind/stl/optional.h>
#include <nanobind/stl/shared_ptr.h>

#include "mlx/distributed/distributed.h"
#include "mlx/distributed/ops.h"

namespace nb = nanobind;
using namespace nb::literals;
using namespace mlx::core;

void init_distributed(nb::module_& parent_module) {
  auto m = parent_module.def_submodule(
      "distributed", "mlx.core.distributed: Communication operations");

  nb::class_<distributed::Group>(
      m,
      "Group",
      R"pbcopy(
        An :class:`mlx.core.distributed.Group` represents a group of independent mlx
        processes that can communicate.
      )pbcopy")
      .def("rank", &distributed::Group::rank, "Get the rank of this process")
      .def("size", &distributed::Group::size, "Get the size of the group")
      .def(
          "split",
          &distributed::Group::split,
          "color"_a,
          "key"_a = -1,
          nb::sig("def split(self, color: int, key: int = -1) -> Group"),
          R"pbdoc(
            Split the group to subgroups based on the provided color.

            Processes that use the same color go to the same group. The ``key``
            argument defines the rank in the new group. The smaller the key the
            smaller the rank. If the key is negative then the rank in the
            current group is used.

            Args:
              color (int): A value to group processes into subgroups.
              key (int, optional): A key to optionally change the rank ordering
                of the processes.
          )pbdoc");

  m.def(
      "is_available",
      &distributed::is_available,
      R"pbdoc(
      Check if a communication backend is available.
      )pbdoc");

  m.def(
      "init",
      &distributed::init,
      "strict"_a = false,
      nb::sig("def init(strict: bool = False) -> Group"),
      R"pbdoc(
        Initialize the communication backend and create the global communication group.

        Args:
          strict (bool, optional): If set to False it returns a singleton group
            in case ``mx.distributed.is_available()`` returns False otherwise
            it throws a runtime error. Default: ``False``

        Returns:
          Group: The group representing all the launched processes.
      )pbdoc");

  m.def(
      "all_sum",
      &distributed::all_sum,
      "x"_a,
      nb::kw_only(),
      "group"_a = nb::none(),
      nb::sig(
          "def all_sum(x: array, *, group: Optional[Group] = None) -> array"),
      R"pbdoc(
        All reduce sum.

        Sum the ``x`` arrays from all processes in the group.

        Args:
          x (array): Input array.
          group (Group): The group of processes that will participate in the
            reduction. If set to ``None`` the global group is used. Default:
            ``None``.

        Returns:
          array: The sum of all ``x`` arrays.
      )pbdoc");

  m.def(
      "all_gather",
      &distributed::all_gather,
      "x"_a,
      nb::kw_only(),
      "group"_a = nb::none(),
      nb::sig(
          "def all_gather(x: array, *, group: Optional[Group] = None) -> array"),
      R"pbdoc(
        Gather arrays from all processes.

        Gather the ``x`` arrays from all processes in the group and concatenate
        them along the first axis. The arrays should all have the same shape.

        Args:
          x (array): Input array.
          group (Group): The group of processes that will participate in the
            gather. If set to ``None`` the global group is used. Default:
            ``None``.

        Returns:
          array: The concatenation of all ``x`` arrays.
      )pbdoc");
}