#include "StreamBuffer.h"
#include "vulkan/vulkan.h"
#include "Graphics.h"


namespace love
{
namespace graphics
{
namespace vulkan
{

static VkBufferUsageFlags getUsageFlags(BufferUsage mode)
{
	switch (mode)
	{
	case BUFFERUSAGE_VERTEX: return VK_BUFFER_USAGE_VERTEX_BUFFER_BIT;
	case BUFFERUSAGE_INDEX: return VK_BUFFER_USAGE_INDEX_BUFFER_BIT;
	case BUFFERUSAGE_UNIFORM: return VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT;
	default:
		throw love::Exception("unsupported BufferUsage mode");
	}
}

StreamBuffer::StreamBuffer(graphics::Graphics *gfx, BufferUsage mode, size_t size)
	: love::graphics::StreamBuffer(mode, size)
	, vgfx(dynamic_cast<Graphics*>(gfx))
{
	loadVolatile();
}

bool StreamBuffer::loadVolatile()
{
	allocator = vgfx->getVmaAllocator();

	VkBufferCreateInfo bufferInfo{};
	bufferInfo.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
	bufferInfo.size = getSize();
	bufferInfo.usage = getUsageFlags(mode);
	bufferInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;

	VmaAllocationCreateInfo allocCreateInfo = {};
	allocCreateInfo.usage = VMA_MEMORY_USAGE_AUTO;
	allocCreateInfo.flags = VMA_ALLOCATION_CREATE_HOST_ACCESS_RANDOM_BIT | VMA_ALLOCATION_CREATE_MAPPED_BIT;	// always mapped

	vmaCreateBuffer(allocator, &bufferInfo, &allocCreateInfo, &buffer, &allocation, &allocInfo);

	usedGPUMemory = 0;

	return true;
}

void StreamBuffer::unloadVolatile()
{
	if (buffer == VK_NULL_HANDLE)
		return;

	vgfx->queueCleanUp([allocator=allocator, buffer=buffer, allocation=allocation](){
		vmaDestroyBuffer(allocator, buffer, allocation);
	});
	buffer = VK_NULL_HANDLE;
}

StreamBuffer::~StreamBuffer()
{
	unloadVolatile();
}

ptrdiff_t StreamBuffer::getHandle() const
{
	return (ptrdiff_t) buffer;
}

love::graphics::StreamBuffer::MapInfo StreamBuffer::map(size_t minsize)
{
	(void)minsize;
	return love::graphics::StreamBuffer::MapInfo((uint8*) allocInfo.pMappedData + usedGPUMemory, getSize());
}

size_t StreamBuffer::unmap(size_t usedSize)
{
	return usedGPUMemory;
}

void StreamBuffer::markUsed(size_t usedSize)
{
	usedGPUMemory += usedSize;
}

void StreamBuffer::nextFrame()
{
	usedGPUMemory = 0;
}

} // vulkan
} // graphics
} // love