// Copyright 2024 Google LLC
// SPDX-License-Identifier: Apache-2.0
//
// 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
//
//     https://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.

#include "gemma/kv_cache.h"

#include "gemma/common.h"  // CallForModel
#include "hwy/aligned_allocator.h"
#include "hwy/base.h"  // ZeroBytes

namespace gcpp {
namespace {
template <class TConfig>
struct CreateKVCache {
  KVCache operator()(size_t prefill_tbatch_size) const {
    KVCache kv_cache = {};

    const size_t size_cache_pos = CachePosSize<TConfig>()();
    if (size_cache_pos != 0) {
      // Allocate more so that prefill can always access one batch, even if
      // near the end of the sequence.
      kv_cache.seq_len = TConfig::kSeqLen + prefill_tbatch_size;
      kv_cache.kv_cache =
          hwy::AllocateAligned<float>(kv_cache.seq_len * size_cache_pos);
    }

    // TODO(patrickms): Add query batching support for Griffin.
    if (TConfig::kGriffinLayers) {
      constexpr size_t kConv1dWidth = TConfig::kConv1dWidth;
      const size_t conv1d_cache_size =
          TConfig::kGriffinLayers * (kConv1dWidth == 0 ? 0 : kConv1dWidth - 1) *
          TConfig::kModelDim;
      if (conv1d_cache_size != 0) {
        kv_cache.conv1d_cache = hwy::AllocateAligned<float>(conv1d_cache_size);
        hwy::ZeroBytes(kv_cache.conv1d_cache.get(),
                       conv1d_cache_size * sizeof(kv_cache.conv1d_cache[0]));
      }

      const size_t rglru_cache_size =
          TConfig::kGriffinLayers * TConfig::kModelDim;
      if (rglru_cache_size != 0) {
        kv_cache.rglru_cache = hwy::AllocateAligned<float>(rglru_cache_size);
        hwy::ZeroBytes(kv_cache.rglru_cache.get(),
                       rglru_cache_size * sizeof(kv_cache.rglru_cache[0]));
      }
    }  // kGriffinLayers

    return kv_cache;
  }
};
}  // namespace

// prefill_tbatch_size is the maximum number of tokens from one query to
// prefill at a time.
KVCache KVCache::Create(Model model_type, size_t prefill_tbatch_size) {
  // TWeight=float is a placeholder and unused because CreateKVCache does not
  // use TConfig::Weight.
  return CallForModel</*TWeight=*/float, CreateKVCache>(model_type,
                                                        prefill_tbatch_size);
}

}  // namespace gcpp