/*
 * Copyright (c) 2025, NVIDIA CORPORATION.  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.
 */

#pragma once

#include <array>
#include <cstdint>
#include <utility>
#include <vector>

namespace torch_ext {
namespace moe_alltoall {

// Enum for indexing into moe_a2a_metainfo tensor
enum MoeA2AMetaInfoIndex : int64_t {
  FLAG_VAL_OFFSET_INDEX = 0,
  LOCAL_TOKEN_COUNTER_OFFSET_INDEX = 1,
  SEND_COUNTERS_OFFSET_INDEX = 2,
  RECV_COUNTERS_OFFSET_INDEX = 3,
  // Dispatch completion flags offset
  DISPATCH_COMPLETION_FLAGS_OFFSET_INDEX = 4,
  // Combine completion flags offset
  COMBINE_COMPLETION_FLAGS_OFFSET_INDEX = 5,
  TOPK_TARGET_RANKS_OFFSET_INDEX = 6,
  TOPK_SEND_INDICES_OFFSET_INDEX = 7,
  PAYLOAD_DATA_OFFSET_INDEX = 8,
  NUM_METAINFO_FIELDS = 9
};

using MoeA2ADataOffsets = std::array<int64_t, NUM_METAINFO_FIELDS>;

inline std::vector<std::pair<char const*, int64_t>> getMoeA2AMetaInfoIndexPairs() {
  return {
      {"MOE_A2A_FLAG_VAL_OFFSET_INDEX", FLAG_VAL_OFFSET_INDEX},
      {"MOE_A2A_LOCAL_TOKEN_COUNTER_OFFSET_INDEX", LOCAL_TOKEN_COUNTER_OFFSET_INDEX},
      {"MOE_A2A_SEND_COUNTERS_OFFSET_INDEX", SEND_COUNTERS_OFFSET_INDEX},
      {"MOE_A2A_RECV_COUNTERS_OFFSET_INDEX", RECV_COUNTERS_OFFSET_INDEX},
      {"MOE_A2A_DISPATCH_COMPLETION_FLAGS_OFFSET_INDEX", DISPATCH_COMPLETION_FLAGS_OFFSET_INDEX},
      {"MOE_A2A_COMBINE_COMPLETION_FLAGS_OFFSET_INDEX", COMBINE_COMPLETION_FLAGS_OFFSET_INDEX},
      {"MOE_A2A_TOPK_TARGET_RANKS_OFFSET_INDEX", TOPK_TARGET_RANKS_OFFSET_INDEX},
      {"MOE_A2A_TOPK_SEND_INDICES_OFFSET_INDEX", TOPK_SEND_INDICES_OFFSET_INDEX},
      {"MOE_A2A_PAYLOAD_DATA_OFFSET_INDEX", PAYLOAD_DATA_OFFSET_INDEX},
      {"MOE_A2A_NUM_METAINFO_FIELDS", NUM_METAINFO_FIELDS},
  };
}

}  // namespace moe_alltoall
}  // namespace torch_ext