SHADE_Y3/SHADE_Engine/src/Serialization/SHSerialization.cpp

#include "SHpch.h"
#include "SHSerializationHelper.hpp"
#include "SHSerialization.h"

#include <yaml-cpp/yaml.h>

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

#include "Graphics/MiddleEnd/Interface/SHRenderable.h"
#include "Math/Transform/SHTransformComponent.h"
#include "Physics/Components/SHRigidBodyComponent.h"
#include "ECS_Base/Managers/SHSystemManager.h"
#include "Scripting/SHScriptEngine.h"

namespace SHADE
{
  void SHSerialization::SerializeSceneToFile(std::filesystem::path const& path)
  {
    YAML::Emitter out;
    SerializeSceneToEmitter(out);
    std::ofstream file(path.c_str());
    if (file.good())
    {
      file << out.c_str();
      file.close();
    }
  }

  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 void DeserializeEntity(YAML::iterator& it, YAML::Node const& node, std::vector<EntityID>& createdEntities, EntityID parentEID = MAX_EID)
  {
    if (!node[EIDNode])
      return;
    EntityID 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]);
  }

  void SHSerialization::DeserializeSceneFromFile(std::filesystem::path const& path)
  {
    //TODO:Shift to using XQ's FileIO
    std::ifstream iFile;
    iFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
    std::string fileContent = "";

    try
    {
      // Open file
      // Read file's buffer contents into streams
      iFile.open(path);
      std::stringstream fileStream;
      fileStream << iFile.rdbuf();

      fileContent = fileStream.str();

      // Close file handler
      iFile.close();
    }
    catch (std::ifstream::failure e)
    {
      SHLOG_ERROR("Could not read file");
    }
    YAML::Node entities = YAML::Load(fileContent);
    std::vector<EntityID> createdEntities{};

    //Create Entities
    for (auto it = entities.begin(); it != entities.end(); ++it)
    {
      DeserializeEntity(it, (*it), createdEntities);
    }

    //Initialize Entity
    auto entityVecIt = createdEntities.begin();
    for (auto it = entities.begin(); it != entities.end(); ++it)
    {
      InitializeEntity(*it, *entityVecIt++);
    }
  }

  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)
  {
    YAML::Emitter out;
    YAML::Node node;
    auto const& sceneGraph = SHSceneManager::GetCurrentSceneGraph();
    for (auto const& eid : entities)
    {
      auto entityNode = sceneGraph.GetNode(eid);
      EmitEntity(entityNode, out);
    }
    return std::basic_string<char>(out.c_str());
  }

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

  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;

    if (const auto transform = SHComponentManager::GetComponent_s<SHTransformComponent>(eid))
    {
      components[rttr::type::get<SHTransformComponent>().get_name().data()] = SHSerializationHelper::SerializeComponentToNode(transform);
    }
    if (const auto renderable = SHComponentManager::GetComponent_s<SHRenderable>(eid))
    {
      components[rttr::type::get<SHRenderable>().get_name().data()] = SHSerializationHelper::SerializeComponentToNode(renderable);
    }
    if (const auto rigidbody = SHComponentManager::GetComponent_s<SHRigidBodyComponent>(eid))
    {
      components[rttr::type::get<SHRigidBodyComponent>().get_name().data()] = SHSerializationHelper::SerializeComponentToNode(rigidbody);
    }
    node[ComponentsNode] = components;

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

    return node;
  }

  template<typename ComponentType, std::enable_if_t<std::is_base_of_v<SHComponent, ComponentType>, bool> = true>
  std::optional<ComponentTypeID> GetComponentID(YAML::Node const& componentNode)
  {
    if (componentNode[rttr::type::get<ComponentType>().get_name().data()])
      return { SHFamilyID<SHComponent>::GetID<ComponentType>() };
    else
      return std::nullopt;
  }

  std::vector<ComponentTypeID> SHSerialization::GetComponentIDList(YAML::Node const& componentsNode)
  {
    std::vector<ComponentTypeID> componentIDList;

    auto id = GetComponentID<SHTransformComponent>(componentsNode);
    if (id.has_value())
      componentIDList.push_back(id.value());

    id = GetComponentID<SHRenderable>(componentsNode);
    if (id.has_value())
      componentIDList.push_back(id.value());

    id = GetComponentID<SHRigidBodyComponent>(componentsNode);
    if (id.has_value())
      componentIDList.push_back(id.value());

    return componentIDList;
  }

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