#include "SHpch.h"

#include <yaml-cpp/yaml.h>
#include "SHSerialization.h"
#include "SHSerializationHelper.hpp"

#include "ECS_Base/Managers/SHEntityManager.h"
#include "Scene/SHSceneManager.h"
#include "Tools/SHException.h"
#include "Assets/SHAssetManager.h"
#include <fstream>

#include "Assets/Asset Types/SHSceneAsset.h"
#include "Camera/SHCameraComponent.h"
#include "Graphics/MiddleEnd/Interface/SHRenderable.h"
#include "Math/Transform/SHTransformComponent.h"
#include "Physics/Components/SHRigidBodyComponent.h"
#include "ECS_Base/Managers/SHSystemManager.h"
#include "Graphics/MiddleEnd/Lights/SHLightComponent.h"
#include "Scripting/SHScriptEngine.h"
#include "Tools/FileIO/SHFileIO.h"

namespace SHADE
{
  bool SHSerialization::SerializeSceneToFile(AssetID const& sceneAssetID)
  {
    auto assetData = SHAssetManager::GetData<SHSceneAsset>(sceneAssetID);
    if(!assetData)
    {
      SHLOG_ERROR("Asset does not exist: {}", sceneAssetID);
      return false;
    }
    YAML::Emitter out;
    SerializeSceneToEmitter(out);
    assetData->data = out.c_str();
    
    return SHAssetManager::SaveAsset(sceneAssetID);
  }

  std::string SHSerialization::SerializeSceneToString()
  {
    YAML::Emitter out;
    SerializeSceneToEmitter(out);
    return std::basic_string<char>(out.c_str());
  }

  void SHSerialization::SerializeSceneToEmitter(YAML::Emitter& out)
  {
    auto const& sceneGraph = SHSceneManager::GetCurrentSceneGraph();
    auto root = sceneGraph.GetRoot();

    SHASSERT(root != nullptr, "Root is null. Failed to serialize scene to node.");

    auto const& children = root->GetChildren();
    out << YAML::BeginSeq;

    auto pred = [&out](SHSceneNode* node) {out << SerializeEntityToNode(node); };
    sceneGraph.Traverse(pred);
    //out << SerializeEntityToNode(child);

    out << YAML::EndSeq;
  }

  static EntityID DeserializeEntity(YAML::iterator& it, YAML::Node const& node, std::vector<EntityID>& createdEntities, EntityID parentEID = MAX_EID)
  {
    EntityID eid = MAX_EID;
    if (!node)
      return eid;
    if (node[EIDNode])
      eid = node[EIDNode].as<EntityID>();
    std::string name = "Default";
    if (node[EntityNameNode])
      name = node[EntityNameNode].as<std::string>();
    //Compile component IDs
    const auto componentIDList = SHSerialization::GetComponentIDList(node[ComponentsNode]);
    eid = SHEntityManager::CreateEntity(componentIDList, eid, name, parentEID);
    createdEntities.push_back(eid);
    if (node[NumberOfChildrenNode])
    {
      if (const int numOfChildren = node[NumberOfChildrenNode].as<int>(); numOfChildren > 0)
      {
        ++it;
        for (int i = 0; i < numOfChildren; ++i)
        {
          DeserializeEntity(it, (*it), createdEntities, eid);
          if ((i + 1) < numOfChildren)
            ++it;
        }
      }
    }

    // Deserialise scripts
    if (node[ScriptsNode])
      SHSystemManager::GetSystem<SHScriptEngine>()->DeserialiseScripts(eid, node[ScriptsNode]);

    return eid;
  }

  std::string SHSerialization::DeserializeSceneFromFile(AssetID const& sceneAssetID) noexcept
  {
    auto assetData = SHAssetManager::GetData<SHSceneAsset>(sceneAssetID);
    if(!assetData)
    {
      SHLOG_ERROR("Attempted to load scene that doesn't exist {}", sceneAssetID)
      SHSceneManager::SetCurrentSceneAssetID(0);
      return NewSceneName.data();
    }
    YAML::Node entities = YAML::Load(assetData->data);
    std::vector<EntityID> createdEntities{};

    //Create Entities
    for (auto it = entities.begin(); it != entities.end(); ++it)
    {
      DeserializeEntity(it, (*it), createdEntities);
    }
    if (createdEntities.empty())
    {
      SHLOG_ERROR("Failed to create entities from deserializaiton")
        return NewSceneName.data();
    }
    auto entityVecIt = createdEntities.begin();
    AssetQueue assetQueue;
    for (auto it = entities.begin(); it != entities.end(); ++it)
    {
      SHSerializationHelper::FetchAssetsFromComponent<SHRenderable>((*it)[ComponentsNode], *entityVecIt, assetQueue);  
    }
    LoadAssetsFromAssetQueue(assetQueue);
    //Initialize Entity
    entityVecIt = createdEntities.begin();
    for (auto it = entities.begin(); it != entities.end(); ++it)
    {
      InitializeEntity(*it, *entityVecIt++);
    }

    return assetData->name;
  } 

  void SHSerialization::EmitEntity(SHSceneNode* entityNode, YAML::Emitter& out)
  {
    out << SerializeEntityToNode(entityNode);
    auto const& children = entityNode->GetChildren();
    for (auto const& child : children)
    {
      EmitEntity(child, out);
    }
  }

  std::string SHSerialization::SerializeEntitiesToString(std::vector<EntityID> const& entities) noexcept
  {
    YAML::Emitter out;
    YAML::Node node;
    auto const& sceneGraph = SHSceneManager::GetCurrentSceneGraph();
    out << YAML::BeginSeq;
    for (auto const& eid : entities)
    {
      auto entityNode = sceneGraph.GetNode(eid);
      EmitEntity(entityNode, out);
    }
    out << YAML::EndSeq;
    return std::string(out.c_str());
  }

  void SHSerialization::SerializeEntityToFile(std::filesystem::path const& path)
  {
  }

  template<typename ComponentType, std::enable_if_t<std::is_base_of_v<SHComponent, ComponentType>, bool> = true>
  static void AddComponentToComponentNode(YAML::Node& componentsNode, EntityID const& eid)
  {
    if (const ComponentType* component = SHComponentManager::GetComponent_s<ComponentType>(eid))
    {
      componentsNode[rttr::type::get<ComponentType>().get_name().data()] = SHSerializationHelper::SerializeComponentToNode(component);
    }
  }

  template<typename ComponentType, std::enable_if_t<std::is_base_of_v<SHComponent, ComponentType>, bool> = true>
  static void AddConvComponentToComponentNode(YAML::Node& componentsNode, EntityID const& eid)
  {
    if (ComponentType* component = SHComponentManager::GetComponent_s<ComponentType>(eid))
    {
      componentsNode[rttr::type::get<ComponentType>().get_name().data()] = YAML::convert<ComponentType>::encode(*component);
    }
  }


  YAML::Node SHSerialization::SerializeEntityToNode(SHSceneNode* sceneNode)
  {
    YAML::Node node;
    auto eid = sceneNode->GetEntityID();
    auto entity = SHEntityManager::GetEntityByID(eid);
    if (!sceneNode && !entity)
    {
      node = YAML::Null;
      return node;
    }
    node.SetStyle(YAML::EmitterStyle::Block);
    node[EIDNode] = eid;
    node[EntityNameNode] = entity->name;
    node[IsActiveNode] = sceneNode->IsActive();
    auto const& children = sceneNode->GetChildren();
    node[NumberOfChildrenNode] = children.size();

    YAML::Node components;

    AddComponentToComponentNode<SHTransformComponent>(components, eid);
    AddComponentToComponentNode<SHCameraComponent>(components, eid);
    AddConvComponentToComponentNode<SHRenderable>(components, eid);
    AddComponentToComponentNode<SHLightComponent>(components, eid);
    AddComponentToComponentNode<SHRigidBodyComponent>(components, eid);
    AddConvComponentToComponentNode<SHColliderComponent>(components, eid);

    node[ComponentsNode] = components;

    YAML::Node scripts;
    SHSystemManager::GetSystem<SHScriptEngine>()->SerialiseScripts(eid, scripts);
    node[ScriptsNode] = scripts;

    return node;
  }

  EntityID SHSerialization::DeserializeEntitiesFromString(std::string const& data, EntityID const& parentEID) noexcept
  {
    if (data.empty())
      return MAX_EID;
    YAML::Node entities = YAML::Load(data.c_str());
    EntityID eid{ MAX_EID };
    std::vector<EntityID> createdEntities;
    for (auto it = entities.begin(); it != entities.end(); ++it)
    {
      eid = DeserializeEntity(it, *it, createdEntities, parentEID);
    }
    if (createdEntities.empty())
    {
      SHLOG_ERROR("Failed to create entities from deserializaiton")
        return MAX_EID;
    }
    auto entityVecIt = createdEntities.begin();
    for (auto it = entities.begin(); it != entities.end(); ++it)
    {
      InitializeEntity(*it, *entityVecIt++);
    }
    return eid;
  }

  template<typename ComponentType, std::enable_if_t<std::is_base_of_v<SHComponent, ComponentType>, bool> = true>
  static void AddComponentID(std::vector<ComponentTypeID>& idList, YAML::Node const& componentNode)
  {
    if (componentNode[rttr::type::get<ComponentType>().get_name().data()])
      idList.push_back(SHFamilyID<SHComponent>::GetID<ComponentType>());
  }

  std::vector<ComponentTypeID> SHSerialization::GetComponentIDList(YAML::Node const& componentsNode)
  {
    std::vector<ComponentTypeID> componentIDList;
    
    AddComponentID<SHTransformComponent>(componentIDList, componentsNode);
    AddComponentID<SHCameraComponent>(componentIDList, componentsNode);
    AddComponentID<SHRenderable>(componentIDList, componentsNode);
    AddComponentID<SHRigidBodyComponent>(componentIDList, componentsNode);
    AddComponentID<SHLightComponent>(componentIDList, componentsNode);
    AddComponentID<SHColliderComponent>(componentIDList, componentsNode);

    return componentIDList;
  }

  void SHSerialization::LoadAssetsFromAssetQueue(AssetQueue& assetQueue)
  {
    for (auto& [assetId, assetType] : assetQueue)
    {
      switch(assetType)
      {
      case AssetType::INVALID: break;
      case AssetType::SHADER: break;
      case AssetType::SHADER_BUILT_IN: break;
      case AssetType::TEXTURE:
        SHResourceManager::LoadOrGet<SHTexture>(assetId);
        break;
      case AssetType::MESH:
        SHResourceManager::LoadOrGet<SHMesh>(assetId);
        break;
      case AssetType::SCENE: break;
      case AssetType::PREFAB: break;
      case AssetType::MATERIAL:
        SHResourceManager::LoadOrGet<SHMaterial>(assetId);
        break;
      case AssetType::MAX_COUNT: break;
      default: ;
      }
    }
    SHResourceManager::FinaliseChanges();
  }

  void SHSerialization::InitializeEntity(YAML::Node const& entityNode, EntityID const& eid)
  {
    auto const componentsNode = entityNode[ComponentsNode];
    if (!componentsNode)
      return;
    SHSerializationHelper::InitializeComponentFromNode<SHTransformComponent>(componentsNode, eid);
    SHSerializationHelper::InitializeComponentFromNode<SHCameraComponent>(componentsNode, eid);
    SHSerializationHelper::InitializeComponentFromNode<SHRigidBodyComponent>(componentsNode, eid);
    SHSerializationHelper::ConvertNodeToComponent<SHRenderable>(componentsNode, eid);
    SHSerializationHelper::ConvertNodeToComponent<SHColliderComponent>(componentsNode, eid);
    SHSerializationHelper::InitializeComponentFromNode<SHLightComponent>(componentsNode, eid);
  }
}