IIndex.h

#pragma once

#include "IIDMap.h"
#include <fsdk/IAsyncContext.h>
#include <fsdk/IDescriptor.h>

namespace fsdk {

#ifndef DOXYGEN_SHOULD_SKIP_THIS
    DECLARE_SMARTPTR(IStaticDescriptorStorage);
    DECLARE_SMARTPTR(IDynamicDescriptorStorage);
    DECLARE_SMARTPTR(IIndex);
    DECLARE_SMARTPTR(IDenseIndex);
    DECLARE_SMARTPTR(IDynamicIndex);
    DECLARE_SMARTPTR(IIndexBuilder);
    DECLARE_SMARTPTR(IIDMap);
#endif

    enum DynamicIndexState : uint8_t {
        DIS_INVALID = 0, 
        DIS_VALID,       
        DIS_UNKNOWN,     
        DIS_COUNT
    };

    using DescriptorId = size_t;

    struct SearchResult : MatchingResult {
        DescriptorId index;

        SearchResult() noexcept
            : MatchingResult()
            , index(std::numeric_limits<DescriptorId>::max()) {
        }

        SearchResult(float distance, float similarity, DescriptorId index) noexcept
            : MatchingResult(distance, similarity)
            , index(index) {
        }
    };

    struct IStaticDescriptorStorage {
        virtual Result<FSDKError>
        descriptorByIndex(const DescriptorId index, IDescriptor* descriptor) const noexcept = 0;

        virtual uint32_t getDescriptorVersion() const noexcept = 0;

        virtual uint64_t size() const noexcept = 0;
    };

    struct IDynamicDescriptorStorage : IStaticDescriptorStorage {
        virtual ResultValue<FSDKError, DescriptorId> appendDescriptor(const IDescriptor* descriptor) noexcept = 0;

        virtual ResultValue<FSDKError, DescriptorId> appendBatch(const IDescriptorBatch* batch) noexcept = 0;

        virtual Result<FSDKError> removeDescriptor(const DescriptorId index) noexcept = 0;
    };

    struct IIndex : IRefCounted {
        virtual ResultValue<FSDKError, int>
        search(const IDescriptor* reference, int maxResultsCount, SearchResult* results) const noexcept = 0;
    };

    struct IDenseIndex : IStaticDescriptorStorage, IIndex {};

    struct IDynamicIndex : IDynamicDescriptorStorage, IIndex {
        virtual Result<FSDKError> saveToDenseIndex(const char* path) const noexcept = 0;

        virtual Result<FSDKError> saveToDynamicIndex(const char* path) const noexcept = 0;

        virtual uint64_t countOfIndexedDescriptors() const noexcept = 0;

        virtual ResultValue<FSDKError, IIDMapPtr> eraseRemovedDescriptors() noexcept = 0;

        virtual ResultValue<FSDKError, DynamicIndexState> isValidForSearch() const noexcept = 0;

        virtual ResultValue<FSDKError, float> evaluate() const noexcept = 0;
    };

    struct IProgressTracker {
        virtual void progress(const float completion) const noexcept = 0;
    };

    struct IIndexBuilder : IDynamicDescriptorStorage, IRefCounted {
        virtual ResultValue<FSDKError, IDynamicIndex*>
        buildIndex(const IProgressTracker* const progressTracker = nullptr) noexcept = 0;

        virtual ResultValue<FSDKError, Future<ResultValue<FSDKError, IDynamicIndex*>>> buildIndexAsync(
            IAsyncContext* const asyncContext,
            const IProgressTracker* const progressTracker = nullptr) noexcept = 0;
    };


} // namespace fsdk