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 <fstream>
#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
	****************************************************************************/
	void GetFieldValue(std::ifstream& file, std::string& line) noexcept
	{
		line = "";
		std::getline(file, line);
		line = line.substr(line.find_last_of(':') + 2, line.length());
	}

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

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

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

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

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

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

		std::string line;
		SHAssetMeta meta;

		// Get file version
		GetFieldValue(metaFile, line);
		meta.SetVersion(line);

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

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

		metaFile.close();

		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(SHAssetMeta const& meta, AssetPath const& path) noexcept
	{
		std::ofstream metaFile{ path, std::ios_base::out };

		if (!metaFile.is_open())
		{
			// Log error
		}

		metaFile << "Meta Version: " << meta.GetVersion() << "\n";
		metaFile << "ID: " << meta.GetID() << "\n";
		metaFile << "Type: " << static_cast<int>(meta.GetType()) << std::endl;
		metaFile.close();
	}

}