/*
 * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "VMapManager.h"
#include "Errors.h"
#include "Log.h"
#include "MapTree.h"
#include "ModelInstance.h"
#include "VMapDefinitions.h"
#include "WorldModel.h"
#include <G3D/Vector3.h>

namespace VMAP
{
    class ManagedModel
    {
    public:
        explicit ManagedModel(VMapManager& mgr, std::string const& name) : _mgr(mgr), _name(name) { }

        ManagedModel(ManagedModel const&) = delete;
        ManagedModel(ManagedModel&&) = delete;

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

        ~ManagedModel()
        {
            _mgr.releaseModelInstance(_name);
        }

        WorldModel Model;

    private:
        VMapManager& _mgr;
        std::string const& _name;   // valid only while model is held in VMapManager::iLoadedModelFiles
    };

    bool readChunk(FILE* rf, char* dest, const char* compare, uint32 len)
    {
        if (fread(dest, sizeof(char), len, rf) != len) return false;
        return memcmp(dest, compare, len) == 0;
    }

    VMapManager::VMapManager() :
        iEnableLineOfSightCalc(true),
        iEnableHeightCalc(true),
        thread_safe_environment(true),
        GetLiquidFlagsPtr([](uint32 /*liquidTypeId*/) { return 0u; }),
        IsVMAPDisabledForPtr([](uint32 /*mapId*/, uint8 /*disableFlags*/) { return false; })
    {
    }

    VMapManager::~VMapManager() = default;

    InstanceTreeMap::const_iterator VMapManager::GetMapTree(uint32 mapId) const
    {
        // return the iterator if found or end() if not found/NULL
        auto itr = iInstanceMapTrees.find(mapId);
        if (itr != iInstanceMapTrees.cend() && !itr->second)
            itr = iInstanceMapTrees.cend();

        return itr;
    }

    void VMapManager::InitializeThreadUnsafe(std::unordered_map<uint32, std::vector<uint32>> const& mapData)
    {
        // the caller must pass the list of all mapIds that will be used in the VMapManager lifetime
        for (auto const& [mapId, childMapIds] : mapData)
        {
            iInstanceMapTrees[mapId] = nullptr;
            for (uint32 childMapId : childMapIds)
                iParentMapData[childMapId] = mapId;
        }

        thread_safe_environment = false;
    }

    void VMapManager::InitializeThreadUnsafe(uint32 mapId, int32 parentMapId)
    {
        iInstanceMapTrees[mapId] = nullptr;
        if (parentMapId >= 0)
            iParentMapData[mapId] = parentMapId;
    }

    inline static G3D::Vector3 convertPositionToInternalRep(float x, float y, float z)
    {
        G3D::Vector3 pos;
        constexpr float mid = 0.5f * 64.0f * 533.33333333f;
        pos.x = mid - x;
        pos.y = mid - y;
        pos.z = z;

        return pos;
    }

    std::string VMapManager::getMapFileName(uint32 mapId)
    {
        return Trinity::StringFormat("{:04}/{:04}.vmtree", mapId, mapId);
    }

    std::string VMapManager::getTileFileName(uint32 mapID, uint32 tileX, uint32 tileY, std::string_view extension)
    {
        return Trinity::StringFormat("{:04}/{:04}_{:02}_{:02}.{}", mapID, mapID, tileY, tileX, extension);
    }

    LoadResult VMapManager::loadMap(std::string const& basePath, uint32 mapId, uint32 x, uint32 y)
    {
        if (!isMapLoadingEnabled())
            return LoadResult::DisabledInConfig;

        auto instanceTree = iInstanceMapTrees.find(mapId);
        if (instanceTree == iInstanceMapTrees.end())
        {
            if (thread_safe_environment)
                instanceTree = iInstanceMapTrees.insert(InstanceTreeMap::value_type(mapId, nullptr)).first;
            else
                ABORT_MSG("Invalid mapId %u tile [%u, %u] passed to VMapManager after startup in thread unsafe environment",
                    mapId, x, y);
        }

        if (!instanceTree->second)
        {
            std::string mapFileName = getMapFileName(mapId);
            std::unique_ptr<StaticMapTree> newTree = std::make_unique<StaticMapTree>(mapId, basePath);
            LoadResult treeInitResult = newTree->InitMap(mapFileName);
            if (treeInitResult != LoadResult::Success)
                return treeInitResult;

            instanceTree->second = std::move(newTree);
        }

        return instanceTree->second->LoadMapTile(x, y, this);
    }

    void VMapManager::unloadMap(uint32 mapId, uint32 x, uint32 y)
    {
        auto instanceTree = iInstanceMapTrees.find(mapId);
        if (instanceTree != iInstanceMapTrees.end() && instanceTree->second)
        {
            instanceTree->second->UnloadMapTile(x, y, this);
            if (instanceTree->second->numLoadedTiles() == 0)
                instanceTree->second = nullptr;
        }
    }

    void VMapManager::unloadMap(uint32 mapId)
    {
        auto instanceTree = iInstanceMapTrees.find(mapId);
        if (instanceTree != iInstanceMapTrees.end() && instanceTree->second)
        {
            instanceTree->second->UnloadMap();
            if (instanceTree->second->numLoadedTiles() == 0)
                instanceTree->second = nullptr;
        }
    }

    bool VMapManager::isInLineOfSight(uint32 mapId, float x1, float y1, float z1, float x2, float y2, float z2, ModelIgnoreFlags ignoreFlags)
    {
        if (!isLineOfSightCalcEnabled() || IsVMAPDisabledForPtr(mapId, VMAP_DISABLE_LOS))
            return true;

        auto instanceTree = GetMapTree(mapId);
        if (instanceTree != iInstanceMapTrees.end())
        {
            G3D::Vector3 pos1 = convertPositionToInternalRep(x1, y1, z1);
            G3D::Vector3 pos2 = convertPositionToInternalRep(x2, y2, z2);
            if (pos1 != pos2)
                return instanceTree->second->isInLineOfSight(pos1, pos2, ignoreFlags);
        }

        return true;
    }

    /**
    get the hit position and return true if we hit something
    otherwise the result pos will be the dest pos
    */
    bool VMapManager::getObjectHitPos(uint32 mapId, float x1, float y1, float z1, float x2, float y2, float z2, float& rx, float &ry, float& rz, float modifyDist)
    {
        if (isLineOfSightCalcEnabled() && !IsVMAPDisabledForPtr(mapId, VMAP_DISABLE_LOS))
        {
            auto instanceTree = GetMapTree(mapId);
            if (instanceTree != iInstanceMapTrees.end())
            {
                G3D::Vector3 pos1 = convertPositionToInternalRep(x1, y1, z1);
                G3D::Vector3 pos2 = convertPositionToInternalRep(x2, y2, z2);
                G3D::Vector3 resultPos;
                bool result = instanceTree->second->getObjectHitPos(pos1, pos2, resultPos, modifyDist);
                resultPos = convertPositionToInternalRep(resultPos.x, resultPos.y, resultPos.z);
                rx = resultPos.x;
                ry = resultPos.y;
                rz = resultPos.z;
                return result;
            }
        }

        rx = x2;
        ry = y2;
        rz = z2;

        return false;
    }

    /**
    get height or INVALID_HEIGHT if no height available
    */

    float VMapManager::getHeight(uint32 mapId, float x, float y, float z, float maxSearchDist)
    {
        if (isHeightCalcEnabled() && !IsVMAPDisabledForPtr(mapId, VMAP_DISABLE_HEIGHT))
        {
            auto instanceTree = GetMapTree(mapId);
            if (instanceTree != iInstanceMapTrees.end())
            {
                G3D::Vector3 pos = convertPositionToInternalRep(x, y, z);
                float height = instanceTree->second->getHeight(pos, maxSearchDist);
                if (!(height < G3D::finf()))
                    return height = VMAP_INVALID_HEIGHT_VALUE; // No height

                return height;
            }
        }

        return VMAP_INVALID_HEIGHT_VALUE;
    }

    bool VMapManager::getAreaAndLiquidData(uint32 mapId, float x, float y, float z, Optional<uint8> reqLiquidType, AreaAndLiquidData& data) const
    {
        InstanceTreeMap::const_iterator instanceTree = GetMapTree(mapId);
        if (instanceTree != iInstanceMapTrees.end())
        {
            LocationInfo info;
            G3D::Vector3 pos = convertPositionToInternalRep(x, y, z);
            if (instanceTree->second->GetLocationInfo(pos, info))
            {
                data.floorZ = info.ground_Z;
                if (!IsVMAPDisabledForPtr(mapId, VMAP_DISABLE_LIQUIDSTATUS))
                {
                    uint32 liquidType = info.hitModel->GetLiquidType(); // entry from LiquidType.dbc
                    float liquidLevel;
                    if (!reqLiquidType || (GetLiquidFlagsPtr(liquidType) & *reqLiquidType))
                        if (info.hitInstance->GetLiquidLevel(pos, info, liquidLevel))
                            data.liquidInfo.emplace(liquidType, liquidLevel);
                }

                if (!IsVMAPDisabledForPtr(mapId, VMAP_DISABLE_AREAFLAG))
                    data.areaInfo.emplace(info.hitModel->GetWmoID(), info.hitInstance->adtId, info.rootId, info.hitModel->GetMogpFlags(), info.hitInstance->ID);

                return true;
            }
        }

        return false;
    }

    std::shared_ptr<WorldModel> VMapManager::acquireModelInstance(std::string const& basepath, std::string const& filename)
    {
        std::shared_ptr<ManagedModel> worldmodel; // this is intentionally declared before lock so that it is destroyed after it to prevent deadlocks in releaseModelInstance

        //! Critical section, thread safe access to iLoadedModelFiles
        std::lock_guard lock(LoadedModelFilesLock);

        auto& [key, model] = *iLoadedModelFiles.try_emplace(filename).first;
        worldmodel = model.lock();
        if (worldmodel)
            return std::shared_ptr<WorldModel>(worldmodel, &worldmodel->Model);

        worldmodel = std::make_shared<ManagedModel>(*this, key);
        if (!worldmodel->Model.readFile(basepath + filename + ".vmo"))
        {
            TC_LOG_ERROR("misc", "VMapManager: could not load '{}{}.vmo'", basepath, filename);
            return nullptr;
        }
        TC_LOG_DEBUG("maps", "VMapManager: loading file '{}{}'", basepath, filename);

        model = worldmodel;

        return std::shared_ptr<WorldModel>(worldmodel, &worldmodel->Model);
    }

    void VMapManager::releaseModelInstance(std::string const& filename)
    {
        //! Critical section, thread safe access to iLoadedModelFiles
        std::lock_guard lock(LoadedModelFilesLock);

        TC_LOG_DEBUG("maps", "VMapManager: unloading file '{}'", filename);

        std::size_t erased = iLoadedModelFiles.erase(filename);
        if (!erased)
            TC_LOG_ERROR("misc", "VMapManager: trying to unload non-loaded file '{}'", filename);
    }

    LoadResult VMapManager::existsMap(std::string const& basePath, uint32 mapId, uint32 x, uint32 y)
    {
        return StaticMapTree::CanLoadMap(basePath, mapId, x, y, this);
    }

    std::span<ModelInstance const> VMapManager::getModelsOnMap(uint32 mapId) const
    {
        InstanceTreeMap::const_iterator mapTree = GetMapTree(mapId);
        if (mapTree != iInstanceMapTrees.end())
            return mapTree->second->getModelInstances();

        return {};
    }

    int32 VMapManager::getParentMapId(uint32 mapId) const
    {
        auto itr = iParentMapData.find(mapId);
        if (itr != iParentMapData.end())
            return int32(itr->second);

        return -1;
    }

} // namespace VMAP