#include <Vulkan/Buffer.h>
#include <Vulkan/Context.h>
#include <Logger.h>

#include <stdexcept>
#include <algorithm>
#include <cassert>


namespace Vulkan {


Buffer::Buffer() noexcept {
}

Buffer::Buffer(
    Context& context,
    VkDeviceSize size,
    VkBufferUsageFlags usage
)
    : m_context(&context)
{
    assert(*m_context);

    VkBufferCreateInfo create_info {
        .sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO,
        .size = size,
        .usage = usage,
        .sharingMode = VK_SHARING_MODE_EXCLUSIVE,
    };
    if(vkCreateBuffer(
        m_context->device(),
        &create_info,
        nullptr,
        &m_buffer
    ) != VK_SUCCESS)
        throw std::runtime_error("failed to create buffer");
}

Buffer::Buffer(
    Context& context,
    VkDeviceSize size,
    VkBufferUsageFlags usage,
    VkMemoryPropertyFlags memory_properties
)
    : Buffer(context, size, usage)
{
    allocate_and_bind_memory(memory_properties);
}

Buffer::Buffer(Buffer&& other) noexcept
    : m_context(other.m_context)
    , m_buffer(other.m_buffer)
    , m_memory(std::move(other.m_memory))
{
    other.m_context = nullptr;
    other.m_buffer = VK_NULL_HANDLE;
}

Buffer::~Buffer() noexcept {
    if(is_valid()) {
        logger.warning() << "Buffer deleted before being destroyed";
        destroy();
    }
}

Buffer& Buffer::operator=(Buffer&& other) noexcept {
    if(&other != this) {
        using std::swap;
        swap(m_context, other.m_context);
        swap(m_buffer, other.m_buffer);
        swap(m_memory, other.m_memory);
    }
    return *this;
}


VkMemoryRequirements Buffer::memory_requirements() const noexcept {
    assert(is_valid());
    assert(*m_context);

    VkMemoryRequirements memory_requirements;
    vkGetBufferMemoryRequirements(
        m_context->device(),
        m_buffer,
        &memory_requirements
    );

    return memory_requirements;
}


void Buffer::bind_memory(const MemoryBlock& memory_block, VkDeviceSize offset) {
    assert(is_valid());
    assert(*m_context);
    assert(memory_block);

    // m_memory = std::move(memory_block);
    if(vkBindBufferMemory(
        m_context->device(),
        m_buffer,
        memory_block.device_memory(),
        memory_block.offset() + offset
    ) != VK_SUCCESS)
        throw std::runtime_error("failed to bind buffer memory");
}

void Buffer::bind_memory(MemoryBlock&& memory_block) {
    bind_memory(memory_block);
    m_memory = std::move(memory_block);
}

void Buffer::allocate_and_bind_memory(VkMemoryPropertyFlags memory_properties) {
    assert(is_valid());
    assert(*m_context);

    const auto memory_requirements = this->memory_requirements();
    m_memory = m_context->allocator().allocate(
        memory_requirements.size,
        memory_requirements.memoryTypeBits,
        memory_properties
    );

    bind_memory(m_memory);
}


void Buffer::upload(size_t size, void* src_buffer, uint32_t dst_queue_family) {
    assert(is_valid());
    assert(*m_context);

    const bool use_staging_buffer =
        (m_memory.memory_type_info(*m_context).propertyFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) == 0;

    if(use_staging_buffer) {
        auto staging_buffer = Buffer(
            *m_context,
            size,
            VK_BUFFER_USAGE_TRANSFER_SRC_BIT,
            VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT
            | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT
        );

        void* dst_buffer = staging_buffer.memory().map(*m_context);
        std::memcpy(dst_buffer, src_buffer, size);
        staging_buffer.memory().unmap(*m_context);

        m_context->copy_buffer(
            m_buffer,
            staging_buffer,
            dst_queue_family,
            size
        );

        staging_buffer.destroy();
    }
    else {
        void* dst_buffer = m_memory.map(*m_context);
        std::memcpy(dst_buffer, src_buffer, size);
        m_memory.unmap(*m_context);
    }
}


void Buffer::destroy() noexcept {
    assert(is_valid());
    assert(*m_context);

    if(m_memory) {
        m_memory.free();
        m_memory = MemoryBlock();
    }

    vkDestroyBuffer(
        m_context->device(),
        m_buffer,
        nullptr
    );

    m_context = nullptr;
    m_buffer = VK_NULL_HANDLE;
}



}