// Copyright (C) 2009-present, Panagiotis Christopoulos Charitos and contributors.
// All rights reserved.
// Code licensed under the BSD License.
// http://www.anki3d.org/LICENSE

#include <AnKi/Resource/ResourceManager.h>
#include <AnKi/Resource/AsyncLoader.h>
#include <AnKi/Resource/ShaderProgramResourceSystem.h>
#include <AnKi/Resource/AnimationResource.h>
#include <AnKi/Resource/AccelerationStructureScratchAllocator.h>
#include <AnKi/Util/Logger.h>
#include <AnKi/Util/CVarSet.h>

#include <AnKi/Resource/MaterialResource.h>
#include <AnKi/Resource/MeshResource.h>
#include <AnKi/Resource/CpuMeshResource.h>
#include <AnKi/Resource/ScriptResource.h>
#include <AnKi/Resource/DummyResource.h>
#include <AnKi/Resource/ParticleEmitterResource.h>
#include <AnKi/Resource/ImageResource.h>
#include <AnKi/Resource/GenericResource.h>
#include <AnKi/Resource/ImageAtlasResource.h>
#include <AnKi/Resource/ShaderProgramResource.h>
#include <AnKi/Resource/SkeletonResource.h>

namespace anki {

ResourceManager::ResourceManager()
{
}

ResourceManager::~ResourceManager()
{
	ANKI_RESOURCE_LOGI("Destroying resource manager");

	AsyncLoader::freeSingleton();
	ShaderProgramResourceSystem::freeSingleton();
	TransferGpuAllocator::freeSingleton();
	ResourceFilesystem::freeSingleton();

#define ANKI_INSTANTIATE_RESOURCE(className) \
	static_cast<TypeData<className>&>(m_allTypes).m_entries.destroy(); \
	static_cast<TypeData<className>&>(m_allTypes).m_map.destroy();
#include <AnKi/Resource/Resources.def.h>

	AccelerationStructureScratchAllocator::freeSingleton();

	ResourceMemoryPool::freeSingleton();
}

Error ResourceManager::init(AllocAlignedCallback allocCallback, void* allocCallbackData)
{
	ANKI_RESOURCE_LOGI("Initializing resource manager");

	ResourceMemoryPool::allocateSingleton(allocCallback, allocCallbackData);

	ResourceFilesystem::allocateSingleton();
	ANKI_CHECK(ResourceFilesystem::getSingleton().init());

	// Init the thread
	AsyncLoader::allocateSingleton();

	TransferGpuAllocator::allocateSingleton();
	ANKI_CHECK(TransferGpuAllocator::getSingleton().init(g_cvarRsrcTransferScratchMemorySize));

	// Init the programs
	ShaderProgramResourceSystem::allocateSingleton();
	ANKI_CHECK(ShaderProgramResourceSystem::getSingleton().init());

	if(GrManager::getSingleton().getDeviceCapabilities().m_rayTracingEnabled)
	{
		AccelerationStructureScratchAllocator::allocateSingleton();
	}

	return Error::kNone;
}

template<typename T>
Error ResourceManager::loadResource(const CString& filename, ResourcePtr<T>& out, Bool async)
{
	ANKI_ASSERT(!out.isCreated() && "Already loaded");

	TypeData<T>& type = static_cast<TypeData<T>&>(m_allTypes);

	// Check if registered
	using EntryType = typename TypeData<T>::Entry;
	EntryType* entry;
	{
		RLockGuard lock(type.m_mtx);
		auto it = type.m_map.find(filename);
		entry = (it != type.m_map.getEnd()) ? &type.m_entries[*it] : nullptr;
	}

	if(!entry)
	{
		// Resource entry doesn't exist, create one

		WLockGuard lock(type.m_mtx);

		auto it = type.m_map.find(filename); // Search again
		if(it != type.m_map.getEnd())
		{
			entry = &type.m_entries[*it];
		}
		else
		{
			auto arrit = type.m_entries.emplace();
			type.m_map.emplace(filename, arrit.getArrayIndex());
			entry = &(*arrit);
		}
	}

	ANKI_ASSERT(entry);

	// Try loading the resource
	Error err = Error::kNone;
	{
		LockGuard lock(entry->m_mtx);

		if(entry->m_resource == nullptr)
		{
			// Resource hasn't been loaded, load it

			T* rsrc = newInstance<T>(ResourceMemoryPool::getSingleton(), filename, m_uuid.fetchAdd(1));

			// Increment the refcount in that case where async jobs increment it and decrement it in the scope of a load()
			rsrc->retain();

			err = rsrc->load(filename, async);

			// Decrement because of the increment happened a few lines above
			rsrc->release();

			if(err)
			{
				ANKI_RESOURCE_LOGE("Failed to load resource: %s", filename.cstr());
				deleteInstance(ResourceMemoryPool::getSingleton(), rsrc);
			}
			else
			{
				entry->m_resource = rsrc;
			}
		}
	}

	if(!err)
	{
		out.reset(entry->m_resource);
	}

	return err;
}

template<typename T>
void ResourceManager::freeResource(T* ptr)
{
	ANKI_ASSERT(ptr);
	ANKI_ASSERT(ptr->m_refcount.load() == 0);

	TypeData<T>& type = static_cast<TypeData<T>&>(m_allTypes);

	typename TypeData<T>::Entry* entry = nullptr;
	{
		RLockGuard lock(type.m_mtx);
		auto it = type.m_map.find(ptr->m_fname);
		ANKI_ASSERT(it != type.m_map.getEnd());
		entry = &type.m_entries[*it];
	}

	{
		LockGuard lock(entry->m_mtx);
		ANKI_ASSERT(entry->m_resource);
		deleteInstance(ResourceMemoryPool::getSingleton(), entry->m_resource);
		entry->m_resource = nullptr;
	}
}

// Instansiate
#define ANKI_INSTANTIATE_RESOURCE(className) \
	template Error ResourceManager::loadResource<className>(const CString& filename, ResourcePtr<className>& out, Bool async); \
	template void ResourceManager::freeResource<className>(className * ptr);
#include <AnKi/Resource/Resources.def.h>

} // end namespace anki