// Copyright (c) 2024 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 <stdlib.h>
#include <string.h>

#include <stdio.h>
#include "paddle/extension.h"

bool is_in_end(const int64_t id, const int64_t *end_ids, int length) {
    bool flag = false;
    for (int i = 0; i < length; i++) {
        if (id == end_ids[i]) {
            return true;
        }
    }
    return flag;
}

void set_value_by_flags(bool *stop_flags,
                        int64_t *topk_ids,
                        int64_t *next_tokens,
                        const int64_t *end_ids,
                        const int *seq_lens,
                        const int bs,
                        const int end_length,
                        bool beam_search) {
    for (int bi = 0; bi < bs; bi++) {
        if (stop_flags[bi]) {
            if ((seq_lens[bi] == 0)) {
                topk_ids[bi] = -1;
            } else {
                topk_ids[bi] = end_ids[0];
                next_tokens[bi] = end_ids[0];
            }
        } else {
            next_tokens[bi] = topk_ids[bi];
        }
        if (!beam_search && is_in_end(topk_ids[bi], end_ids, end_length)) {
            stop_flags[bi] = true;
        }
    }
}

void GetStopFlagsMulti(const paddle::Tensor &topk_ids,
                       const paddle::Tensor &stop_flags,
                       const paddle::Tensor &seq_lens,
                       const paddle::Tensor &end_ids,
                       const paddle::Tensor &next_tokens,
                       const bool beam_search) {
    std::vector<int64_t> shape = topk_ids.shape();
    int64_t bs_now = shape[0];
    int64_t end_length = end_ids.shape()[0];
    set_value_by_flags(const_cast<bool *>(stop_flags.data<bool>()),
                       const_cast<int64_t *>(topk_ids.data<int64_t>()),
                       const_cast<int64_t *>(next_tokens.data<int64_t>()),
                       end_ids.data<int64_t>(),
                       seq_lens.data<int>(),
                       bs_now,
                       end_length,
                       false);
}

PD_BUILD_STATIC_OP(set_stop_value_multi_ends_cpu)
    .Inputs({"topk_ids", "stop_flags", "seq_lens", "end_ids", "next_tokens"})
    .Attrs({"beam_search: bool"})
    .Outputs({"topk_ids_out", "stop_flags_out", "next_tokens_out"})
    .SetInplaceMap({{"topk_ids", "topk_ids_out"},
                    {"stop_flags", "stop_flags_out"},
                    {"next_tokens", "next_tokens_out"}})
    .SetKernelFn(PD_KERNEL(GetStopFlagsMulti));