SHADE_Y3/SHADE_Engine/src/Assets/SHAssetMetaHandler.cpp

/******************************************************************************
 * \file    SHAssetMetaHandler.cpp
 * \author  Loh Xiao Qi
 * \brief   Implementations for SHAssetMetaHandler.h
 * 
 * \copyright	Copyright (c) 2021 Digipen Institute of Technology. Reproduction
 *						or disclosure of this file or its contents without the prior
 *						written consent of Digipen Institute of Technology is prohibited
 ******************************************************************************/
#include "SHpch.h"
#include "SHAssetMetaHandler.h"
#include <sstream>

namespace SHADE
{
	/****************************************************************************
	 * \param   reference to ifstream file to read line from
	 * \param   reference to string to store line into
	
	 * \brief   Helper function to retrieve field value from meta data file
	 *					for processing
	****************************************************************************/
	bool GetFieldValue(std::ifstream& file, std::string& line) noexcept
	{
		line = "";
    if (std::getline(file, line))
    {
      line = line.substr(line.find_last_of(':') + 2, line.length());
      return true;
    }
    return false;
	}

	/****************************************************************************
	 * \param   String containing extension of resource file

	 * \brief   Get correct resource type from file extension of resource.
	****************************************************************************/
	AssetType SHAssetMetaHandler::GetTypeFromExtension(AssetExtension ext) noexcept
	{
		for (auto i{0}; i < EXTENSIONS_COUNT; ++i)
		{
			if (strcmp(ext.c_str(), EXTENSIONS[i].data()) == 0)
			{
				return static_cast<AssetType>(i);
			}
		}

		return AssetType::INVALID;
	}

	/****************************************************************************
	 * \param   String containing extension of resource file

	 * \brief   Get correct resource type from file extension of resource.
	****************************************************************************/
	AssetExtension SHAssetMetaHandler::GetExtensionFromType(AssetType type) noexcept
	{
		return AssetExtension(EXTENSIONS[static_cast<size_t>(type)]);
	}

	/****************************************************************************
	 * \param   Create class containing meta data from meta file

	 * \brief   path to meta data file
	****************************************************************************/
	SHAsset SHAssetMetaHandler::RetrieveMetaData(AssetPath const& path) noexcept
	{
		std::ifstream metaFile{ path.string(), std::ios_base::in };
		if (!metaFile.is_open())
		{
      SHLOG_ERROR("Unable to open meta file: {}", path.string());
      return {};
		}

		std::string line;
		SHAsset meta;

		// Get resource name
		GetFieldValue(metaFile, line);
		std::stringstream nameStream{ line };
		AssetName name;
		nameStream >> name;
		meta.name = name;

		// Get resource id
		GetFieldValue(metaFile, line);
		std::stringstream idStream{ line };
		AssetID id;
		idStream >> id;
		meta.id = id;

		// Get resource type
		GetFieldValue(metaFile, line);
		std::stringstream typeStream{ line };
		AssetTypeMeta type;
		typeStream >> type;
		meta.type = static_cast<AssetType>(type);
    
    meta.isSubAsset = false;
    meta.parent = 0;

    // Burn Line
    if (std::getline(metaFile, line))
    {
      // Name Line
      while(GetFieldValue(metaFile, line))
      {
        auto subAsset = new SHAsset();

        // Get resource name
        std::stringstream nameStream{ line };
        AssetName name;
        nameStream >> name;
        subAsset->name = name;

        // Get resource id
        GetFieldValue(metaFile, line);
        std::stringstream idStream{ line };
        AssetID id;
        idStream >> id;
        subAsset->id = id;

        // Get resource type
        GetFieldValue(metaFile, line);
        std::stringstream typeStream{ line };
        AssetTypeMeta type;
        typeStream >> type;
        subAsset->type = static_cast<AssetType>(type);

        subAsset->isSubAsset = true;
        subAsset->parent = meta.id;

        meta.subAssets.push_back(subAsset);
      }
    }

		metaFile.close();

		meta.path = path.parent_path().string() + "/" + path.stem().string();
    meta.path.make_preferred();

		return meta;
	}

	/****************************************************************************
	 * \param   Asset meta data to be written into
	 * \param   Path to be written into

	 * \brief   Writes meta data into text file
	****************************************************************************/
	void SHAssetMetaHandler::WriteMetaData(SHAsset const& meta) noexcept
	{
    if (meta.isSubAsset)
    {
      SHLOG_WARNING("Cannot write subasset meta: {}", meta.name);
      return;
    }

		//TODO: Write into binary eventually
		std::string path{ meta.path.string() };
		path.append(META_EXTENSION);

		std::ofstream metaFile{ path, std::ios_base::out | std::ios_base::trunc };

		if (!metaFile.is_open())
		{
			SHLOG_ERROR("Asset write path is invalid: {}", path);
			return;
		}

		metaFile << "Name: " << meta.name << "\n";
		metaFile << "ID: " << meta.id << "\n";
		metaFile << "Type: " << static_cast<AssetTypeMeta>(meta.type) << std::endl;

    if (!meta.subAssets.empty())
    {
      metaFile << "Sub Assets:\n";

      for (auto const& subAsset : meta.subAssets)
      {
        WriteSubAssetMeta(metaFile, *subAsset);
      }
    }

		metaFile.close();
	}

  void SHAssetMetaHandler::WriteSubAssetMeta(std::ofstream& metaFile, SHAsset const& subAsset) noexcept
  {
    metaFile << "Name: " << subAsset.name << "\n";
    metaFile << "ID: " << subAsset.id << "\n";
    metaFile << "Type: " << static_cast<AssetTypeMeta>(subAsset.type) << std::endl;
  }
}