#ifndef OPENMW_ESM_CELL_H
#define OPENMW_ESM_CELL_H

#include <list>
#include <string>
#include <vector>

#include "components/esm/defs.hpp"
#include "components/esm/esmcommon.hpp"
#include "components/esm/refid.hpp"

#include <components/misc/constants.hpp>

#include "cellref.hpp"

namespace MWWorld
{
    class ESMStore;
}

namespace ESM
{
    class ESMReader;
    class ESMWriter;

    /* Moved cell reference tracking object. This mainly stores the target cell
            of the reference, so we can easily know where it has been moved when another
            plugin tries to move it independently.
        Unfortunately, we need to implement this here.
        */
    class MovedCellRef
    {
    public:
        RefNum mRefNum;

        // Coordinates of target exterior cell
        int32_t mTarget[2];

        // The content file format does not support moving objects to an interior cell.
        // The save game format does support moving to interior cells, but uses a different mechanism
        // (see the MovedRefTracker implementation in MWWorld::CellStore for more details).
    };

    /// Overloaded compare operator used to search inside a list of cell refs.
    bool operator==(const MovedCellRef& ref, const RefNum& refNum);
    bool operator==(const CellRef& ref, const RefNum& refNum);

    typedef std::list<MovedCellRef> MovedCellRefTracker;
    typedef std::list<std::pair<CellRef, bool>> CellRefTracker;

    struct CellRefTrackerPredicate
    {
        RefNum mRefNum;

        CellRefTrackerPredicate(const RefNum& refNum)
            : mRefNum(refNum)
        {
        }
        bool operator()(const std::pair<CellRef, bool>& refdelPair) { return refdelPair.first == mRefNum; }
    };

    /* Cells hold data about objects, creatures, statics (rocks, walls,
       buildings) and landscape (for exterior cells). Cells frequently
       also has other associated LAND and PGRD records. Combined, all this
       data can be huge, and we cannot load it all at startup. Instead,
       the strategy we use is to remember the file position of each cell
       (using ESMReader::getContext()) and jumping back into place
       whenever we need to load a given cell.
     */
    struct Cell
    {
        static const ESM::StringRefId sDefaultWorldspaceId;

        constexpr static RecNameInts sRecordId = REC_CELL;

        static constexpr int sSize = Constants::CellSizeInUnits;

        /// Return a string descriptor for this record type. Currently used for debugging / error logs only.
        static std::string_view getRecordType() { return "Cell"; }

        enum class GetNextRefMode
        {
            LoadAll,
            LoadOnlyMoved,
            LoadOnlyNotMoved,
        };

        enum Flags
        {
            Interior = 0x01, // Interior cell
            HasWater = 0x02, // Does this cell have a water surface
            NoSleep = 0x04, // Is it allowed to sleep here (without a bed)
            QuasiEx = 0x80 // Behave like exterior (Tribunal+), with
                           // skybox and weather
        };

        struct DATAstruct
        {
            int32_t mFlags{ 0 };
            int32_t mX{ 0 }, mY{ 0 };
        };

        struct AMBIstruct
        {
            Color mAmbient{ 0 }, mSunlight{ 0 }, mFog{ 0 };
            float mFogDensity{ 0.f };
        };

        Cell()
            : mName("")
            , mRegion(ESM::RefId())
            , mHasAmbi(true)
            , mWater(0)
            , mHasWaterHeightSub(false)
            , mMapColor(0)
            , mRefNumCounter(0)
        {
        }
        ESM::RefId mId;
        // Interior cells are indexed by this (it's the 'id'), for exterior
        // cells it is optional.
        std::string mName;

        // Optional region name for exterior and quasi-exterior cells.
        RefId mRegion;

        std::vector<ESM_Context> mContextList; // File position; multiple positions for multiple plugin support
        DATAstruct mData;

        AMBIstruct mAmbi;
        bool mHasAmbi;

        float mWater; // Water level
        bool mHasWaterHeightSub;
        int32_t mMapColor;
        // Counter for RefNums. This is only used during content file editing and has no impact on gameplay.
        // It prevents overwriting previous refNums, even if they were deleted.
        // as that would collide with refs when a content file is upgraded.
        int32_t mRefNumCounter;

        // References "leased" from another cell (i.e. a different cell
        //  introduced this ref, and it has been moved here by a plugin)
        CellRefTracker mLeasedRefs;
        MovedCellRefTracker mMovedRefs;

        void postLoad(ESMReader& esm);

        // This method is left in for compatibility with esmtool. Parsing moved references currently requires
        //  passing ESMStore, bit it does not know about this parameter, so we do it this way.
        void load(ESMReader& esm, bool& isDeleted, bool saveContext = true); // Load everything (except references)
        void loadNameAndData(ESMReader& esm, bool& isDeleted); // Load NAME and DATAstruct
        void loadCell(
            ESMReader& esm, bool saveContext = true); // Load everything, except NAME, DATAstruct and references

        void save(ESMWriter& esm, bool isDeleted = false) const;
        void saveTempMarker(ESMWriter& esm, int32_t tempCount) const;

        bool isExterior() const { return !(mData.mFlags & Interior); }

        int32_t getGridX() const { return mData.mX; }

        int32_t getGridY() const { return mData.mY; }

        bool hasWater() const { return ((mData.mFlags & HasWater) != 0) || isExterior(); }

        void setHasWaterHeightSub(bool hasWater) { mHasWaterHeightSub = hasWater; }

        bool hasAmbient() const { return mHasAmbi; }

        void setHasAmbient(bool hasAmbi) { mHasAmbi = hasAmbi; }

        // Restore the given reader to the stored position. Will try to open
        // the file matching the stored file name. If you want to read from
        // somewhere other than the file system, you need to pre-open the
        // ESMReader, and the filename must match the stored filename
        // exactly.
        void restore(ESMReader& esm, size_t iCtx) const;

        std::string getDescription() const;
        ///< Return a short string describing the cell (mostly used for debugging/logging purpose)

        /* Get the next reference in this cell, if any. Returns false when
           there are no more references in the cell.

           All fields of the CellRef struct are overwritten. You can safely
           reuse one memory location without blanking it between calls.
        */
        static bool getNextRef(ESMReader& esm, CellRef& ref, bool& deleted);

        static bool getNextRef(ESMReader& esm, CellRef& cellRef, bool& deleted, MovedCellRef& movedCellRef, bool& moved,
            GetNextRefMode mode = GetNextRefMode::LoadAll);

        /* This fetches an MVRF record, which is used to track moved references.
         * Since they are comparably rare, we use a separate method for this.
         */
        static bool getNextMVRF(ESMReader& esm, MovedCellRef& mref);

        void blank();
        ///< Set record to default state (does not touch the ID/index).

        const ESM::RefId& updateId();

        static ESM::RefId generateIdForCell(bool exterior, std::string_view cellName, int x, int y);
    };
}
#endif
