/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * This file is part of the LibreOffice project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   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 .

 */

#pragma once

#include "address.hxx"

#include <svl/listener.hxx>

#include <memory>

#include <unordered_map>

class ScDocument;

struct ScLookupCacheMap;

struct ScQueryEntry;

enum class LookupSearchMode;

/** Lookup cache for one range used with interpreter functions such as VLOOKUP

    and MATCH. Caches query for a specific row and the resulting address looked

    up, in case other lookups of the same query in the same row are to be

    performed, which usually occur to obtain a different offset column of the

    same query.

 */

class ScLookupCache final : public SvtListener

{

public:

    enum Result

    {

        NOT_CACHED,         /// Query not found in cache.

        CRITERIA_DIFFERENT, /// Different criteria for same query position exists.

        NOT_AVAILABLE,      /// Criteria not available in lookup range.

        FOUND               /// Criteria found.

    };

    enum QueryOp

    {

        UNKNOWN,

        EQUAL,

        LESS_EQUAL,

        GREATER_EQUAL

    };

    class QueryCriteria

    {

        union

        {

            double          mfVal;

            const OUString *mpStr;

        };

        bool                mbAlloc;

        bool                mbString;

        QueryOp             meOp;

        LookupSearchMode    meSearchMode;

        void deleteString()

        {

            if (mbAlloc && mbString)

                delete mpStr;

        }

        QueryCriteria & operator=( const QueryCriteria & r ) = delete;

    public:

        explicit QueryCriteria( const ScQueryEntry & rEntry, LookupSearchMode nSearchMode );

        QueryCriteria( const QueryCriteria & r );

        ~QueryCriteria();

        QueryOp getQueryOp() const { return meOp; }

        LookupSearchMode getSearchMode() const { return meSearchMode; }

        void setDouble( double fVal )

        {

            deleteString();

            mbAlloc = mbString = false;

            mfVal = fVal;

        }

        void setString( const OUString & rStr )

        {

            deleteString();

            mbAlloc = mbString = true;

            mpStr = new OUString( rStr);

        }

        bool operator==( const QueryCriteria & r ) const

        {

            return meOp == r.meOp && meSearchMode == r.meSearchMode && mbString == r.mbString &&

                (mbString ? (*mpStr == *r.mpStr) : (mfVal == r.mfVal));

        }

        bool isEmptyStringQuery() const

        {

            return (getQueryOp() == QueryOp::EQUAL) && mbString && mpStr && mpStr->isEmpty();

        }

    };

    /// MUST be new'd because Notify() deletes.

                            ScLookupCache( ScDocument * pDoc, const ScRange & rRange, ScLookupCacheMap & cacheMap )

                                : maRange( rRange), mpDoc( pDoc), mCacheMap(cacheMap) {}

    /// Remove from document structure and delete (!) cache on modify hint.

    virtual void Notify( const SfxHint& rHint ) override;

    /// @returns document address in o_rResultAddress if Result==FOUND

            Result          lookup( ScAddress & o_rResultAddress,

                                    const QueryCriteria & rCriteria,

                                    const ScAddress & rQueryAddress ) const;

            SCROW           lookup( const QueryCriteria & rCriteria ) const;

    /** Insert query and result.

        @param bAvailable

            Pass sal_False if the search didn't deliver a result. A subsequent

            lookup() then will return Result::NOT_AVAILABLE.

        @returns successful insertion.

      */

            bool            insert( const ScAddress & rResultAddress,

                                    const QueryCriteria & rCriteria,

                                    const ScAddress & rQueryAddress,

                                    const bool bAvailable );

    const ScRange&  getRange() const { return maRange; }

    ScLookupCacheMap & getCacheMap() const { return mCacheMap; }

    struct Hash

    {

        size_t operator()( const ScRange & rRange ) const

        {

            // Lookups are performed on the first column.

            return rRange.hashStartColumn();

        }

    };

private:

    struct QueryKey

    {

        SCROW           mnRow;

        SCTAB           mnTab;

        QueryOp         meOp;

        LookupSearchMode meSearchMode;

        QueryKey( const ScAddress & rAddress, const QueryOp eOp, LookupSearchMode eSearchMode ) :

            mnRow( rAddress.Row()),

            mnTab( rAddress.Tab()),

            meOp( eOp),

            meSearchMode( eSearchMode)

        {

        }

        bool operator==( const QueryKey & r ) const

        {

            return mnRow == r.mnRow && mnTab == r.mnTab && meOp == r.meOp && meOp != UNKNOWN &&

                meSearchMode == r.meSearchMode;

        }

        struct Hash

        {

            size_t operator()( const QueryKey & r ) const

            {

                return (static_cast<size_t>(r.mnTab) << 24) ^

                    (static_cast<size_t>(r.meOp) << 22) ^

                    (static_cast<size_t>(r.meSearchMode) << 20) ^

                    static_cast<size_t>(r.mnRow);

            }

        };

    };

    struct QueryCriteriaAndResult

    {

        QueryCriteria   maCriteria;

        ScAddress       maAddress;

        QueryCriteriaAndResult( const QueryCriteria & rCriteria, const ScAddress & rAddress ) :

            maCriteria( rCriteria),

            maAddress( rAddress)

        {

        }

    };

    typedef std::unordered_map<QueryKey, QueryCriteriaAndResult, QueryKey::Hash> QueryMap;

    QueryMap maQueryMap;

    ScRange         maRange;

    ScDocument *    mpDoc;

    ScLookupCacheMap & mCacheMap;

    ScLookupCache( const ScLookupCache & ) = delete;

    ScLookupCache & operator=( const ScLookupCache & ) = delete;

};

// Struct because including lookupcache.hxx in document.hxx isn't wanted.

struct ScLookupCacheMap

{

    std::unordered_map< ScRange, std::unique_ptr<ScLookupCache>, ScLookupCache::Hash > aCacheMap;

};

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