//
// Created by atdunbg on 2026/9/20.
//

#include <Engine/Vulkan/Buffer.h>
#include <Engine/Vulkan/Device.h>
#include <Engine/Vulkan/MemoryAllocator.h>
#include <Engine/Core/Log.h>

#include <cstring>

#include "Engine/Core/Stats.h"

namespace Engine {

    Buffer::Buffer(Device& device, MemoryAllocator& allocator,
               vk::DeviceSize size, vk::BufferUsageFlags usage,
               vk::MemoryPropertyFlags memProps)
    : m_Device(device), m_Allocator(allocator) , m_Size(size)
    {
        vk::BufferCreateInfo bufferInfo;
        bufferInfo.setSize(size)
                  .setUsage(usage)
                  .setSharingMode(vk::SharingMode::eExclusive);

        m_Buffer = m_Device.GetDevice().createBuffer(bufferInfo);

        auto reqs = m_Device.GetDevice().getBufferMemoryRequirements(m_Buffer);
        auto alloc = allocator.Allocate(reqs, memProps);

        m_Memory = alloc.Memory;
        m_Offset = alloc.Offset;
        m_MappedPtr = alloc.MappedPtr;

        m_Device.GetDevice().bindBufferMemory(m_Buffer, m_Memory, m_Offset);

        m_Allocation = alloc;   // 成员变量，保存起来

        STATS.AddBuffer(m_Size);
    }

    Buffer::~Buffer()
    {
        m_Device.GetDevice().destroyBuffer(m_Buffer);
        m_Allocator.Free(m_Allocation);
        STATS.RemoveBuffer(m_Size);
    }

    void Buffer::Upload(const void* data, vk::DeviceSize size, vk::DeviceSize offset)
    {
        if (!m_MappedPtr) {
            ENGINE_ERROR("Buffer::Upload: buffer is not host visible");
            return;
        }
        memcpy(static_cast<char*>(m_MappedPtr) + offset, data, size);

        // flush 整个内存块，避免对齐问题
        vk::MappedMemoryRange range;
        range.setMemory(m_Memory)
             .setOffset(0)
             .setSize(VK_WHOLE_SIZE);

        m_Device.GetDevice().flushMappedMemoryRanges(range);
    }
} // namespace Engine