// Copyright (c) 2025 PaddlePaddle Authors. 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.

#include "paddle/extension.h"

#ifndef PD_BUILD_STATIC_OP
#define PD_BUILD_STATIC_OP(name) PD_BUILD_OP(static_op_##name)
#endif

__global__ void draft_model_update_seq_lens_this_time_kernel(
    const int64_t* base_model_draft_tokens,
    int* base_model_seq_lens_this_time,
    const int* base_model_seq_lens_encoder,
    const bool* base_model_stop_flags,
    int bsz,
    int base_model_draft_token_len) {
    int tid = threadIdx.x;
    if (tid < bsz) {
        if (!base_model_stop_flags[tid] &&
            base_model_seq_lens_encoder[tid] == 0) {
            const int64_t* base_model_draft_tokens_now =
                base_model_draft_tokens + tid * base_model_draft_token_len;
            int token_num = 0;

            for (int i = 0; i < base_model_draft_token_len; ++i) {
                if (base_model_draft_tokens_now[i] != -1) {
                    token_num++;
                }
            }
            base_model_seq_lens_this_time[tid] = token_num;
        } else if (base_model_stop_flags[tid]) {
            base_model_seq_lens_this_time[tid] = 0;
        }
    }
}

void DraftModelPostprocess(const paddle::Tensor& base_model_draft_tokens,
                           const paddle::Tensor& base_model_seq_lens_this_time,
                           const paddle::Tensor& base_model_seq_lens_encoder,
                           const paddle::Tensor& base_model_stop_flags) {
    int real_bsz = base_model_seq_lens_this_time.shape()[0];
    auto cu_stream = base_model_seq_lens_this_time.stream();
    int block_size = (real_bsz + 32 - 1) / 32 * 32;
    int base_model_draft_token_len = base_model_draft_tokens.shape()[1];
    draft_model_update_seq_lens_this_time_kernel<<<1,
                                                   block_size,
                                                   0,
                                                   cu_stream>>>(
        base_model_draft_tokens.data<int64_t>(),
        const_cast<int*>(base_model_seq_lens_this_time.data<int>()),
        base_model_seq_lens_encoder.data<int>(),
        base_model_stop_flags.data<bool>(),
        real_bsz,
        base_model_draft_token_len);
}

PD_BUILD_STATIC_OP(draft_model_postprocess)
    .Inputs({"base_model_draft_tokens",
             "base_model_seq_lens_this_time",
             "base_model_seq_lens_encoder",
             "base_model_stop_flags"})
    .Outputs({"base_model_draft_tokens_out",
              "base_model_seq_lens_this_time_out",
              "base_model_stop_flags_out"})
    .SetInplaceMap({{"base_model_draft_tokens", "base_model_draft_tokens_out"},
                    {"base_model_seq_lens_this_time",
                     "base_model_seq_lens_this_time_out"},
                    {"base_model_stop_flags", "base_model_stop_flags_out"}})
    .SetKernelFn(PD_KERNEL(DraftModelPostprocess));
