// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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.

#pragma once

#include "utils/Status.h"

#include <memory>
#include <string>
#include <vector>

namespace milvus {
namespace engine {

enum class EngineType {
    INVALID = 0,
    FAISS_IDMAP = 1,
    FAISS_IVFFLAT,
    FAISS_IVFSQ8,
    NSG_MIX,
    FAISS_IVFSQ8H,
    MAX_VALUE = FAISS_IVFSQ8H,
};

enum class MetricType {
    L2 = 1,
    IP = 2,
};

class ExecutionEngine {
 public:
    virtual Status
    AddWithIds(int64_t n, const float* xdata, const int64_t* xids) = 0;

    virtual size_t
    Count() const = 0;

    virtual size_t
    Size() const = 0;

    virtual size_t
    Dimension() const = 0;

    virtual size_t
    PhysicalSize() const = 0;

    virtual Status
    Serialize() = 0;

    virtual Status
    Load(bool to_cache = true) = 0;

    virtual Status
    CopyToGpu(uint64_t device_id) = 0;

    virtual Status
    CopyToIndexFileToGpu(uint64_t device_id) = 0;

    virtual Status
    CopyToCpu() = 0;

    virtual std::shared_ptr<ExecutionEngine>
    Clone() = 0;

    virtual Status
    Merge(const std::string& location) = 0;

    virtual Status
    Search(int64_t n, const float* data, int64_t k, int64_t nprobe, float* distances, int64_t* labels) const = 0;

    virtual std::shared_ptr<ExecutionEngine>
    BuildIndex(const std::string& location, EngineType engine_type) = 0;

    virtual Status
    Cache() = 0;

    virtual Status
    GpuCache(uint64_t gpu_id) = 0;

    virtual Status
    Init() = 0;

    virtual EngineType
    IndexEngineType() const = 0;

    virtual MetricType
    IndexMetricType() const = 0;

    virtual std::string
    GetLocation() const = 0;
};

using ExecutionEnginePtr = std::shared_ptr<ExecutionEngine>;

}  // namespace engine
}  // namespace milvus