//========================================================================
// ResCache.cpp : Defines a simple resource cache
//
// Part of the GameCode4 Application
//
// GameCode4 is the sample application that encapsulates much of the source code
// discussed in "Game Coding Complete - 4th Edition" by Mike McShaffry and David
// "Rez" Graham, published by Charles River Media. 
// ISBN-10: 1133776574 | ISBN-13: 978-1133776574
//
// If this source code has found it's way to you, and you think it has helped you
// in any way, do the authors a favor and buy a new copy of the book - there are 
// detailed explanations in it that compliment this code well. Buy a copy at Amazon.com
// by clicking here: 
//    http://www.amazon.com/gp/product/1133776574/ref=olp_product_details?ie=UTF8&me=&seller=
//
// There's a companion web site at http://www.mcshaffry.com/GameCode/
// 
// The source code is managed and maintained through Google Code: 
//    http://code.google.com/p/gamecode4/
//
// (c) Copyright 2012 Michael L. McShaffry and David Graham
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser GPL v3
// as published by the Free Software Foundation.
//
// 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 
// http://www.gnu.org/licenses/lgpl-3.0.txt for more details.
//
// You should have received a copy of the GNU Lesser GPL v3
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
//
//========================================================================

#include "../Debugging/Logger.h"
#include "../Unix/GameCodeStd.h"
#include "../Utilities/String.h"
#include <list>
#include <map>
#include <cctype>			// for std::tolower

#include "ResCache.h"

// [munnellg] replaces Win32 function call from book.
// TODO(munnellg) - make properly cross-platform
static std::filesystem::path GetCurrentDirectory() {
	std::filesystem::path exe = std::filesystem::canonical("/proc/self/exe");
	return exe.parent_path();
}

//
//  Resource::Resource
//
Resource::Resource(const std::string &name) 
{ 
	m_name=name;
	std::transform(m_name.begin(), m_name.end(), m_name.begin(), (int(*)(int)) std::tolower);
}


//========================================================================
// class ResourceZipFile					- not discussed in the book
//
//    This class implements the IResourceFile interface with a ZipFile.
//
ResourceZipFile::~ResourceZipFile() 
{ 
	SAFE_DELETE(m_pZipFile); 
}


bool ResourceZipFile::VOpen()
{
	GCC_INFO("Opening ResourceZipFile");
	m_pZipFile = GCC_NEW ZipFile;
	if (m_pZipFile)
	{
		return m_pZipFile->Init(m_resFileName.c_str());
	}
	return false;
}


int ResourceZipFile::VGetRawResourceSize(const Resource &r)
{
	int resourceNum = m_pZipFile->Find(r.m_name.c_str());
	if (resourceNum == -1)
		return -1;

	return m_pZipFile->GetFileLen(resourceNum);
}

int ResourceZipFile::VGetRawResource(const Resource &r, char *buffer)
{
	int size = 0;
	std::optional<int> resourceNum = m_pZipFile->Find(r.m_name.c_str());
	if (resourceNum)
	{
		size = m_pZipFile->GetFileLen(*resourceNum);
		m_pZipFile->ReadFile(*resourceNum, buffer);
	}
	return size;
}

int ResourceZipFile::VGetNumResources() const
{
	return (m_pZipFile==NULL) ? 0 : m_pZipFile->GetNumFiles();
}

std::string ResourceZipFile::VGetResourceName(int num) const
{
	std::string resName = "";
	if (m_pZipFile != NULL && num >= 0 && num < m_pZipFile->GetNumFiles())
	{
		resName = m_pZipFile->GetFilename(num);
	}
	return resName;
}

//========================================================================
// class DevelopmentResourceZipFile					- not discussed in the book
//
//    This class fakes a ZIP file from a normal directory, and is used in the 
//    editor.
//

DevelopmentResourceZipFile::DevelopmentResourceZipFile(const std::wstring resFileName, const Mode mode)
	: ResourceZipFile(resFileName) 
{ 
	m_mode=mode; 

	std::filesystem::path dir = GetCurrentDirectory();

	m_AssetsDir = dir / "Assets";	
}

int DevelopmentResourceZipFile::Find(const std::string &name)
{
	std::string lowerCase = name;
	std::transform(lowerCase.begin(), lowerCase.end(), lowerCase.begin(), (int(*)(int)) std::tolower);
	ZipContentsMap::const_iterator i = m_DirectoryContentsMap.find(lowerCase);
	if (i==m_DirectoryContentsMap.end())
		return -1;

	return i->second;
}

bool DevelopmentResourceZipFile::VOpen()
{
	GCC_INFO("Opening DevelopmentResourceZipFile");
	if (m_mode != Editor)
	{
		return ResourceZipFile::VOpen();
	}

	if (m_mode == Editor)
	{
		return ReadAssetsDirectory(m_AssetsDir);
	}
	else
	{
		// TODO(munnellg) - See if we can get this working
		// FUTURE WORK - iterate through the ZipFile contents and go grab WIN32_FIND_DATA 
		//   elements for each one. Then it would be possible to compare the dates/times of the
		//   asset in the Zip file with the source asset.
		GCC_ASSERT(0 && "Not implemented yet");
	}

	return true;
}

int DevelopmentResourceZipFile::VGetRawResourceSize(const Resource &r)
{
	int size = 0;

	if (m_mode == Editor)
	{
		int num = Find(r.m_name.c_str());
		if (num == -1)
			return -1;

		return m_AssetFileInfo[num].file_size();
	}

	return ResourceZipFile::VGetRawResourceSize(r);
}

int DevelopmentResourceZipFile::VGetRawResource(const Resource &r, char *buffer)
{
	if (m_mode == Editor)
	{
		int num = Find(r.m_name.c_str());
		if (num == -1)
			return -1;

		FILE *f = fopen(m_AssetFileInfo[num].path().c_str(), "rb");
		GCC_ASSERT(f);
		size_t bytes = fread(buffer, 1, m_AssetFileInfo[num].file_size(), f);
		fclose(f);
		return bytes;
	}

	return ResourceZipFile::VGetRawResource(r, buffer);
}

int DevelopmentResourceZipFile::VGetNumResources() const
{
	return (m_mode == Editor) ? m_AssetFileInfo.size() : ResourceZipFile::VGetNumResources();
}

std::string DevelopmentResourceZipFile::VGetResourceName(int num) const
{
	if (m_mode == Editor)
	{
		std::filesystem::path absolutePath = m_AssetFileInfo[num].path();
		std::filesystem::path relativePath = absolutePath.lexically_relative(m_AssetsDir);
		std::string name = relativePath.string();
		std::transform(name.begin(), name.end(), name.begin(), (int(*)(int)) std::tolower);
		return name;
	}

	return ResourceZipFile::VGetResourceName(num);
}

bool DevelopmentResourceZipFile::ReadAssetsDirectory(std::filesystem::path dir)
{
	for (const auto &entry : std::filesystem::directory_iterator(dir))
	{
		if (entry.is_directory())
		{
			if (!ReadAssetsDirectory(entry))
				return false;
		}
		else if (entry.is_regular_file())
		{			
			std::filesystem::path relativePath = entry.path().lexically_relative(m_AssetsDir);
			std::string assetId = relativePath.string();
			std::transform(assetId.begin(), assetId.end(), assetId.begin(), (int(*)(int)) std::tolower);
			m_DirectoryContentsMap[assetId] = m_AssetFileInfo.size();
			m_AssetFileInfo.push_back(entry);
		}
	}

	return true;
}





//
// ResHandle::ResHandle							- Chapter 8, page 223
//
ResHandle::ResHandle(Resource & resource, char *buffer, unsigned int size, ResCache *pResCache)
: m_resource(resource)
{
	m_buffer = buffer;
	m_size = size;
	m_extra = NULL;
	m_pResCache = pResCache;
}

//
// ResHandle::ResHandle							- Chapter 8, page 223
//
ResHandle::~ResHandle()
{
	SAFE_DELETE_ARRAY(m_buffer);
	m_pResCache->MemoryHasBeenFreed(m_size);
}

//
// ResCache::ResCache							- Chapter 8, page 227
//
ResCache::ResCache(const unsigned int sizeInMb, IResourceFile *resFile)
{
	m_cacheSize = sizeInMb * 1024 * 1024;				// total memory size
	m_allocated = 0;									// total memory allocated
	m_file = resFile;
}

//
// ResCache::~ResCache							- Chapter 8, page 227
//
ResCache::~ResCache()
{
	while (!m_lru.empty())
	{
		FreeOneResource();
	}
	SAFE_DELETE(m_file);
}

//
// ResCache::Init								- Chapter 8, page 227
//
bool ResCache::Init()
{ 
	bool retValue = false;
	if ( m_file->VOpen() )
	{
		RegisterLoader(std::shared_ptr<IResourceLoader>(GCC_NEW DefaultResourceLoader()));
		retValue = true;
	}
	return retValue;
}

//
// ResCache::RegisterLoader						- Chapter 8, page 225
// 
//    The loaders are discussed on the page refereced above - this method simply adds the loader
//    to the resource cache.
//
void ResCache::RegisterLoader(std::shared_ptr<IResourceLoader> loader )
{
	m_resourceLoaders.push_front(loader);
}


//
// ResCache::GetHandle							- Chapter 8, page 227
//
std::shared_ptr<ResHandle> ResCache::GetHandle(Resource * r)
{
	std::shared_ptr<ResHandle> handle(Find(r));	
	if (handle==NULL)
	{
		handle = Load(r);
		GCC_ASSERT(handle);
	}
	else
	{
		Update(handle);
	}
	return handle;
}

//
// ResCache::Load								- Chapter 8, page 228-230
//
std::shared_ptr<ResHandle> ResCache::Load(Resource *r)
{
	// Create a new resource and add it to the lru list and map

	std::shared_ptr<IResourceLoader> loader;
	std::shared_ptr<ResHandle> handle;

	for (ResourceLoaders::iterator it = m_resourceLoaders.begin(); it != m_resourceLoaders.end(); ++it)
	{
		std::shared_ptr<IResourceLoader> testLoader = *it;

		if (WildcardMatch(testLoader->VGetPattern().c_str(), r->m_name.c_str()))
		{
			loader = testLoader;
			break;
		}
	}

	if (!loader)
	{
		GCC_ASSERT(loader && "Default resource loader not found!");
		return handle;		// Resource not loaded!
	}

	int rawSize = m_file->VGetRawResourceSize(*r);
	if (rawSize < 0)
	{
		GCC_ASSERT(rawSize > 0 && "Resource size returned -1 - Resource not found");
		return std::shared_ptr<ResHandle>();
	}

	int allocSize = rawSize + ((loader->VAddNullZero()) ? (1) : (0));
	char *rawBuffer = loader->VUseRawFile() ? Allocate(allocSize) : GCC_NEW char[allocSize];
	// TODO(munnellg) - This is a bug. What if rawBuffer is NULL?
	memset(rawBuffer, 0, allocSize);

	if (rawBuffer == NULL || m_file->VGetRawResource(*r, rawBuffer) == 0)
	{
		// resource cache out of memory
		return std::shared_ptr<ResHandle>();
	}

	char *buffer = NULL;
	unsigned int size = 0;

	if (loader->VUseRawFile())
	{
		buffer = rawBuffer;
		handle = std::shared_ptr<ResHandle>(GCC_NEW ResHandle(*r, buffer, rawSize, this));
	}
	else
	{
		size = loader->VGetLoadedResourceSize(rawBuffer, rawSize);
		buffer = Allocate(size);
		if (rawBuffer==NULL || buffer==NULL)
		{
			// resource cache out of memory
			return std::shared_ptr<ResHandle>();
		}
		handle = std::shared_ptr<ResHandle>(GCC_NEW ResHandle(*r, buffer, size, this));
		bool success = loader->VLoadResource(rawBuffer, rawSize, handle);

		// [mrmike] - This was added after the chapter went to copy edit. It is used for those
		//            resoruces that are converted to a useable format upon load, such as a compressed
		//            file. If the raw buffer from the resource file isn't needed, it shouldn't take up
		//            any additional memory, so we release it.
		//
		if (loader->VDiscardRawBufferAfterLoad())
		{
			SAFE_DELETE_ARRAY(rawBuffer);
		}

		if (!success)
		{
			// resource cache out of memory
			return std::shared_ptr<ResHandle>();
		}
	}

	GCC_INFO("Updating LRU queue");
	if (handle)
	{
		m_lru.push_front(handle);
		m_resources[r->m_name] = handle;
	}

	GCC_ASSERT(loader && "Default resource loader not found!");
	return handle;		// ResCache is out of memory!
}

//
// ResCache::Find									- Chapter 8, page 228
//
std::shared_ptr<ResHandle> ResCache::Find(Resource * r)
{
	ResHandleMap::iterator i = m_resources.find(r->m_name);
	if (i==m_resources.end())
		return std::shared_ptr<ResHandle>();

	return i->second;
}

//
// ResCache::Update									- Chapter 8, page 228
//
void ResCache::Update(std::shared_ptr<ResHandle> handle)
{
	m_lru.remove(handle);
	m_lru.push_front(handle);
}



//
// ResCache::Allocate								- Chapter 8, page 230
//
char *ResCache::Allocate(unsigned int size)
{
	if (!MakeRoom(size))
		return NULL;

	char *mem = GCC_NEW char[size];
	if (mem)
	{
		m_allocated += size;
	}

	return mem;
}


//
// ResCache::FreeOneResource						- Chapter 8, page 231
//
void ResCache::FreeOneResource()
{
	ResHandleList::iterator gonner = m_lru.end();
	gonner--;

	std::shared_ptr<ResHandle> handle = *gonner;

	m_lru.pop_back();							
	m_resources.erase(handle->m_resource.m_name);
	// Note - you can't change the resource cache size yet - the resource bits could still actually be
	// used by some sybsystem holding onto the ResHandle. Only when it goes out of scope can the memory
	// be actually free again.
}


//
// ResCache::MakeRoom									- Chapter 8, page 231
//
bool ResCache::MakeRoom(unsigned int size)
{
	if (size > m_cacheSize)
	{
		return false;
	}

	// return null if there's no possible way to allocate the memory
	while (size > (m_cacheSize - m_allocated))
	{
		// The cache is empty, and there's still not enough room.
		if (m_lru.empty())
			return false;

		FreeOneResource();
	}

	return true;
}

//
//	ResCache::Free									- Chapter 8, page 228
//
void ResCache::Free(std::shared_ptr<ResHandle> gonner)
{
	m_lru.remove(gonner);
	m_resources.erase(gonner->m_resource.m_name);
	// Note - the resource might still be in use by something,
	// so the cache can't actually count the memory freed until the
	// ResHandle pointing to it is destroyed.

	//m_allocated -= gonner->m_resource.m_size;
	//delete gonner;
}


//
//  ResCache::MemoryHasBeenFreed					- not described in the book
//
//     This is called whenever the memory associated with a resource is actually freed
//
void ResCache::MemoryHasBeenFreed(unsigned int size)
{
	m_allocated -= size;
}

//
// ResCache::Match									- not described in the book
//
//   Searches the resource cache assets for files matching the pattern. Useful for providing a 
//   a list of levels for a main menu screen, for example.
//
std::vector<std::string> ResCache::Match(const std::string pattern)
{
	std::vector<std::string> matchingNames;
	if (m_file==NULL)
		return matchingNames;
	int numFiles = m_file->VGetNumResources();
	for (int i=0; i<numFiles; ++i)
	{
		std::string name = m_file->VGetResourceName(i);
		std::transform(name.begin(), name.end(), name.begin(), (int(*)(int)) std::tolower);
		if (WildcardMatch(pattern.c_str(), name.c_str()))
		{
			matchingNames.push_back(name);
		}
	}
	return matchingNames;
}


//
// ResCache::Preload								- Chapter 8, page 236
//
int ResCache::Preload(const std::string pattern, void (*progressCallback)(int, bool &))
{
	if (m_file==NULL)
		return 0;

	int numFiles = m_file->VGetNumResources();
	int loaded = 0;
	bool cancel = false;
	for (int i=0; i<numFiles; ++i)
	{
		Resource resource(m_file->VGetResourceName(i));

		if (WildcardMatch(pattern.c_str(), resource.m_name.c_str()))
		{
			std::shared_ptr<ResHandle> handle = g_pApp->m_ResCache->GetHandle(&resource);
			++loaded;
		}

		if (progressCallback != NULL)
		{
			progressCallback(i * 100 / numFiles, cancel);
		}
	}
}