#pragma once

#include <library/cpp/threading/future/core/future.h>

#include <util/generic/string.h>
#include <util/generic/vector.h>
#include <util/generic/hash_set.h>
#include <util/generic/maybe.h>

namespace NSQLComplete {

struct TFolderEntry {
    static constexpr const char* Folder = "Folder";
    static constexpr const char* Table = "Table";

    static THashSet<TString> KnownTypes;

    TString Type;
    TString Name;

    friend bool operator==(const TFolderEntry& lhs, const TFolderEntry& rhs) = default;
};

struct TListFilter {
    TMaybe<THashSet<TString>> Types;
    bool IsUnknownAllowed = false;
};

struct TListRequest {
    TString Cluster;

    // `Path` structure is defined by a `System`.
    // Can end with a folder entry name hint.
    // For example, `/local/exa` lists a folder `/local`,
    // but can rank and filter entries by a hint `exa`.
    TString Path;

    TListFilter Filter;
    size_t Limit = 128;
};

struct TListResponse {
    size_t NameHintLength = 0;
    TVector<TFolderEntry> Entries;
};

struct TDescribeTableRequest {
    TString TableCluster;
    TString TablePath;
    TString ColumnPrefix;
    size_t ColumnsLimit = 128; // TODO: introduce default limit constant
};

struct TDescribeTableResponse {
    bool IsExisting = false;
    TVector<TString> Columns;
};

class ISchema: public TThrRefBase {
public:
    using TPtr = TIntrusivePtr<ISchema>;

    virtual NThreading::TFuture<TListResponse> List(const TListRequest& request) const = 0;

    virtual NThreading::TFuture<TDescribeTableResponse>
    Describe(const TDescribeTableRequest& request) const = 0;
};

} // namespace NSQLComplete