#include "Buffer.h"
#include "Graphics.h"

namespace love {
namespace graphics {
namespace vulkan {

static VkBufferUsageFlags getUsageBit(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");
	}
}

static VkBufferUsageFlags getVulkanUsageFlags(BufferUsageFlags flags) {
	VkBufferUsageFlags vkFlags = 0;
	for (int i = 0; i < BUFFERUSAGE_MAX_ENUM; i++) {
		BufferUsageFlags flag = static_cast<BufferUsageFlags>(1u << i);
		if (flags & flag) {
			vkFlags |= getUsageBit((BufferUsage)i);
		}
	}
	return vkFlags;
}

Buffer::Buffer(love::graphics::Graphics* gfx, const Settings& settings, const std::vector<DataDeclaration>& format, const void* data, size_t size, size_t arraylength)
	: love::graphics::Buffer(gfx, settings, format, size, arraylength), usageFlags(settings.usageFlags), gfx(gfx) {
	loadVolatile();
}

bool Buffer::loadVolatile() {
	Graphics* vgfx = (Graphics*)gfx;
	allocator = vgfx->getVmaAllocator();

	VkBufferCreateInfo bufferInfo{};
	bufferInfo.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
	bufferInfo.size = getSize();
	bufferInfo.usage = getVulkanUsageFlags(usageFlags);

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

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

	return true;
}

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

	Graphics* vgfx = (Graphics*)gfx;
	auto device = vgfx->getDevice();

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

	buffer = VK_NULL_HANDLE;
}

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

void* Buffer::map(MapType map, size_t offset, size_t size) {
	char* data = (char*)allocInfo.pMappedData;
	return (void*) (data + offset);
}

bool Buffer::fill(size_t offset, size_t size, const void *data) {
	void* dst = (void*)((char*)allocInfo.pMappedData + offset);
	memcpy(dst, data, size);
	return true;
}

void Buffer::unmap(size_t usedoffset, size_t usedsize) {
	(void)usedoffset;
	(void)usedsize;
}

void Buffer::copyTo(love::graphics::Buffer* dest, size_t sourceoffset, size_t destoffset, size_t size) {
	throw love::Exception("not implemented yet");
}
} // vulkan
} // graphics
} // love