// Copyright (C) 2019-2020 Zilliz. 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 <cstdint>

#include "common/Chunk.h"

namespace milvus {

std::pair<std::vector<std::string_view>, FixedVector<bool>>
StringChunk::StringViews(
    std::optional<std::pair<int64_t, int64_t>> offset_len = std::nullopt) {
    auto start_offset = 0;
    auto len = row_nums_;
    if (offset_len.has_value()) {
        start_offset = offset_len->first;
        len = offset_len->second;
        AssertInfo(
            start_offset >= 0 && start_offset < row_nums_,
            "Retrieve string views with out-of-bound offset:{}, len:{}, wrong",
            start_offset,
            len);
        AssertInfo(
            len >= 0 && len <= row_nums_,
            "Retrieve string views with out-of-bound offset:{}, len:{}, wrong",
            start_offset,
            len);
        AssertInfo(
            start_offset + len <= row_nums_,
            "Retrieve string views with out-of-bound offset:{}, len:{}, wrong",
            start_offset,
            len);
    }

    std::vector<std::string_view> ret;
    ret.reserve(len);
    auto end_offset = start_offset + len;
    for (auto i = start_offset; i < end_offset; i++) {
        ret.emplace_back(data_ + offsets_[i], offsets_[i + 1] - offsets_[i]);
    }
    if (nullable_) {
        FixedVector<bool> res_valid(valid_.begin() + start_offset,
                                    valid_.begin() + end_offset);
        return {ret, std::move(res_valid)};
    }
    return {ret, {}};
}

std::pair<std::vector<std::string_view>, FixedVector<bool>>
StringChunk::ViewsByOffsets(const FixedVector<int32_t>& offsets) {
    std::vector<std::string_view> ret;
    FixedVector<bool> valid_res;
    size_t size = offsets.size();
    ret.reserve(size);
    valid_res.reserve(size);
    for (auto i = 0; i < size; ++i) {
        auto idx = offsets[i];
        auto start = offsets_[idx];
        ret.emplace_back(data_ + start, offsets_[idx + 1] - start);
        valid_res.emplace_back(isValid(idx));
    }
    return {ret, valid_res};
}

}  // namespace milvus
