/* Copyright 2024 The OpenXLA 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.
==============================================================================*/

#ifndef XLA_PJRT_PLUGIN_XLA_CPU_CPU_TOPOLOGY_DESCRIPTION_H_
#define XLA_PJRT_PLUGIN_XLA_CPU_CPU_TOPOLOGY_DESCRIPTION_H_

#include <cstdint>
#include <memory>
#include <string>
#include <type_traits>
#include <utility>
#include <vector>

#include "absl/container/flat_hash_map.h"
#include "absl/status/statusor.h"
#include "absl/strings/string_view.h"
#include "absl/types/span.h"
#include "xla/layout.h"
#include "xla/pjrt/pjrt_client.h"
#include "xla/pjrt/pjrt_compiler.h"
#include "xla/pjrt/pjrt_device_description.h"
#include "xla/pjrt/plugin/xla_cpu/cpu_topology.h"

namespace xla {

class CpuTopologyDescription : public PjRtTopologyDescription {
 public:
  // `cpu_device_ids` is the list of logical device ids for the CPU devices and
  // will be used to initialize the CPU topology.
  CpuTopologyDescription(const PjRtPlatformId platform_id,
                         const absl::string_view platform_name,
                         const absl::string_view platform_version,
                         std::vector<CpuTopology::CpuDevice> cpu_devices,
                         absl::Span<const std::string> machine_attributes)
      : platform_id_(platform_id),
        platform_name_(platform_name),
        platform_version_(platform_version),
        cpu_topology_(std::move(cpu_devices),
                      std::vector<std::string>(machine_attributes.begin(),
                                               machine_attributes.end())) {}

  bool operator==(const CpuTopologyDescription& other) const {
    return this->platform_id() == other.platform_id() &&
           this->platform_name() == other.platform_name() &&
           this->platform_version() == other.platform_version() &&
           this->cpu_topology().devices() == other.cpu_topology().devices();
  }

  PjRtPlatformId platform_id() const override { return platform_id_; }

  absl::string_view platform_name() const override { return platform_name_; }

  absl::string_view platform_version() const override {
    return platform_version_;
  }

  std::vector<std::unique_ptr<const PjRtDeviceDescription>> DeviceDescriptions()
      const override;

  const CpuTopology& cpu_topology() const { return cpu_topology_; }
  const CpuTopology* cpu_topology_ptr() const { return &cpu_topology_; }

  // No subslice is supported.
  bool is_subslice_topology() const override { return false; }

  // TODO(b/319478189): We support multi-host CPU computations and should
  // correctly report process count.
  absl::StatusOr<int> ProcessCount() const override { return 1; }

  absl::StatusOr<int> CoreCountOfDefaultType() const override {
    return cpu_topology_.number_of_devices();
  }

  absl::StatusOr<int> LogicalDeviceCountOfDefaultType() const override {
    return cpu_topology_.number_of_devices();
  }

  absl::StatusOr<int> CoreCountOfDefaultTypePerProcess() const override {
    return cpu_topology_.number_of_devices();
  }

  absl::StatusOr<int> CoreCountOfDefaultTypePerChip() const override {
    return 1;
  }

  absl::StatusOr<std::string> Serialize() const override;

  // Returns vendor specific attributes about the topology.
  const absl::flat_hash_map<std::string, PjRtDeviceAttribute>& Attributes()
      const override {
    return attributes_;
  }

  absl::StatusOr<Layout> GetDefaultLayout(
      PrimitiveType element_type,
      absl::Span<const int64_t> dims) const override;

 private:
  const PjRtPlatformId platform_id_;
  const std::string platform_name_;
  const std::string platform_version_;
  const CpuTopology cpu_topology_;
  absl::flat_hash_map<std::string, xla::PjRtDeviceAttribute> attributes_;
};

}  // namespace xla

#endif  // XLA_PJRT_PLUGIN_XLA_CPU_CPU_TOPOLOGY_DESCRIPTION_H_