// 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 "knowhere/index/vector_index/IndexBinaryIDMAP.h"

#include <faiss/IndexBinaryFlat.h>
#include <faiss/MetaIndexes.h>
#include <faiss/index_factory.h>

#include <string>

#include "knowhere/common/Exception.h"
#include "knowhere/index/vector_index/adapter/VectorAdapter.h"

namespace milvus {
namespace knowhere {

BinarySet
BinaryIDMAP::Serialize(const Config& config) {
    if (!index_) {
        KNOWHERE_THROW_MSG("index not initialize");
    }

    std::lock_guard<std::mutex> lk(mutex_);
    return SerializeImpl(index_type_);
}

void
BinaryIDMAP::Load(const BinarySet& index_binary) {
    std::lock_guard<std::mutex> lk(mutex_);
    LoadImpl(index_binary, index_type_);
}

DatasetPtr
BinaryIDMAP::Query(const DatasetPtr& dataset_ptr, const Config& config) {
    if (!index_) {
        KNOWHERE_THROW_MSG("index not initialize");
    }
    GET_TENSOR_DATA(dataset_ptr)

    auto k = config[meta::TOPK].get<int64_t>();
    auto elems = rows * k;
    size_t p_id_size = sizeof(int64_t) * elems;
    size_t p_dist_size = sizeof(float) * elems;
    auto p_id = static_cast<int64_t*>(malloc(p_id_size));
    auto p_dist = static_cast<float*>(malloc(p_dist_size));

    QueryImpl(rows, reinterpret_cast<const uint8_t*>(p_data), k, p_dist, p_id, config);

    auto ret_ds = std::make_shared<Dataset>();
    ret_ds->Set(meta::IDS, p_id);
    ret_ds->Set(meta::DISTANCE, p_dist);

    return ret_ds;
}

int64_t
BinaryIDMAP::Count() {
    if (!index_) {
        KNOWHERE_THROW_MSG("index not initialize");
    }
    return index_->ntotal;
}

int64_t
BinaryIDMAP::Dim() {
    if (!index_) {
        KNOWHERE_THROW_MSG("index not initialize");
    }
    return index_->d;
}

void
BinaryIDMAP::Add(const DatasetPtr& dataset_ptr, const Config& config) {
    if (!index_) {
        KNOWHERE_THROW_MSG("index not initialize");
    }

    std::lock_guard<std::mutex> lk(mutex_);
    GET_TENSOR_DATA_ID(dataset_ptr)

    index_->add_with_ids(rows, reinterpret_cast<const uint8_t*>(p_data), p_ids);
}

void
BinaryIDMAP::Train(const DatasetPtr& dataset_ptr, const Config& config) {
    // users will assign the metric type when querying
    // so we let Tanimoto be the default type
    constexpr faiss::MetricType metric_type = faiss::METRIC_Tanimoto;

    const char* desc = "BFlat";
    auto dim = config[meta::DIM].get<int64_t>();
    auto index = faiss::index_binary_factory(dim, desc, metric_type);
    index_.reset(index);
}

const uint8_t*
BinaryIDMAP::GetRawVectors() {
    try {
        auto file_index = dynamic_cast<faiss::IndexBinaryIDMap*>(index_.get());
        auto flat_index = dynamic_cast<faiss::IndexBinaryFlat*>(file_index->index);
        return flat_index->xb.data();
    } catch (std::exception& e) {
        KNOWHERE_THROW_MSG(e.what());
    }
}

const int64_t*
BinaryIDMAP::GetRawIds() {
    try {
        auto file_index = dynamic_cast<faiss::IndexBinaryIDMap*>(index_.get());
        return file_index->id_map.data();
    } catch (std::exception& e) {
        KNOWHERE_THROW_MSG(e.what());
    }
}

void
BinaryIDMAP::AddWithoutIds(const DatasetPtr& dataset_ptr, const Config& config) {
    if (!index_) {
        KNOWHERE_THROW_MSG("index not initialize");
    }

    std::lock_guard<std::mutex> lk(mutex_);
    GET_TENSOR_DATA(dataset_ptr)

    std::vector<int64_t> new_ids(rows);
    for (int i = 0; i < rows; ++i) {
        new_ids[i] = i;
    }

    index_->add_with_ids(rows, reinterpret_cast<const uint8_t*>(p_data), new_ids.data());
}

void
BinaryIDMAP::QueryImpl(int64_t n, const uint8_t* data, int64_t k, float* distances, int64_t* labels,
                       const Config& config) {
    // assign the metric type
    auto bin_flat_index = dynamic_cast<faiss::IndexBinaryIDMap*>(index_.get())->index;
    bin_flat_index->metric_type = GetMetricType(config[Metric::TYPE].get<std::string>());

    auto i_distances = reinterpret_cast<int32_t*>(distances);
    bin_flat_index->search(n, data, k, i_distances, labels, bitset_);

    // if hamming, it need transform int32 to float
    if (bin_flat_index->metric_type == faiss::METRIC_Hamming) {
        int64_t num = n * k;
        for (int64_t i = 0; i < num; i++) {
            distances[i] = static_cast<float>(i_distances[i]);
        }
    }
}

}  // namespace knowhere
}  // namespace milvus
