// Copyright 2010 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include "VideoCommon/FramebufferManagerBase.h"

#include <algorithm>
#include <array>
#include <memory>
#include <tuple>

#include "VideoCommon/RenderBase.h"
#include "VideoCommon/VideoConfig.h"

std::unique_ptr<FramebufferManagerBase> g_framebuffer_manager;

std::unique_ptr<XFBSourceBase>
    FramebufferManagerBase::m_realXFBSource;  // Only used in Real XFB mode
FramebufferManagerBase::VirtualXFBListType
    FramebufferManagerBase::m_virtualXFBList;  // Only used in Virtual XFB mode
std::array<const XFBSourceBase*, FramebufferManagerBase::MAX_VIRTUAL_XFB>
    FramebufferManagerBase::m_overlappingXFBArray;

unsigned int FramebufferManagerBase::m_EFBLayers = 1;

FramebufferManagerBase::FramebufferManagerBase()
{
  // Can't hurt
  m_overlappingXFBArray.fill(nullptr);
}

FramebufferManagerBase::~FramebufferManagerBase()
{
  // Necessary, as these are static members
  // (they really shouldn't be and should be refactored at some point).
  m_virtualXFBList.clear();
  m_realXFBSource.reset();
}

void FramebufferManagerBase::CopyToXFB(u32 xfbAddr, u32 fbStride, u32 fbHeight,
                                       const EFBRectangle& sourceRc, float Gamma)
{
}

void FramebufferManagerBase::CopyToVirtualXFB(u32 xfbAddr, u32 fbStride, u32 fbHeight,
                                              const EFBRectangle& sourceRc, float Gamma)
{
  if (!g_framebuffer_manager)
    return;

  VirtualXFBListType::iterator vxfb = FindVirtualXFB(xfbAddr, sourceRc.GetWidth(), fbHeight);

  if (m_virtualXFBList.end() == vxfb)
  {
    if (m_virtualXFBList.size() < MAX_VIRTUAL_XFB)
    {
      // create a new Virtual XFB and place it at the front of the list
      m_virtualXFBList.emplace_front();
      vxfb = m_virtualXFBList.begin();
    }
    else
    {
      // Replace the last virtual XFB
      --vxfb;
    }
  }
  // else // replace existing virtual XFB

  // move this Virtual XFB to the front of the list.
  if (m_virtualXFBList.begin() != vxfb)
    m_virtualXFBList.splice(m_virtualXFBList.begin(), m_virtualXFBList, vxfb);

  u32 target_width, target_height;
  std::tie(target_width, target_height) = g_framebuffer_manager->GetTargetSize();

  // recreate if needed
  if (vxfb->xfbSource &&
      (vxfb->xfbSource->texWidth != target_width || vxfb->xfbSource->texHeight != target_height))
    vxfb->xfbSource.reset();

  if (!vxfb->xfbSource)
  {
    vxfb->xfbSource =
        g_framebuffer_manager->CreateXFBSource(target_width, target_height, m_EFBLayers);
    if (!vxfb->xfbSource)
      return;

    vxfb->xfbSource->texWidth = target_width;
    vxfb->xfbSource->texHeight = target_height;
  }

  vxfb->xfbSource->srcAddr = vxfb->xfbAddr = xfbAddr;
  vxfb->xfbSource->srcWidth = vxfb->xfbWidth = sourceRc.GetWidth();
  vxfb->xfbSource->srcHeight = vxfb->xfbHeight = fbHeight;

  vxfb->xfbSource->sourceRc = g_renderer->ConvertEFBRectangle(sourceRc);

  // keep stale XFB data from being used
  ReplaceVirtualXFB();

  // Copy EFB data to XFB and restore render target again
  vxfb->xfbSource->CopyEFB(Gamma);
}

FramebufferManagerBase::VirtualXFBListType::iterator
FramebufferManagerBase::FindVirtualXFB(u32 xfbAddr, u32 width, u32 height)
{
  const u32 srcLower = xfbAddr;
  const u32 srcUpper = xfbAddr + 2 * width * height;

  return std::find_if(m_virtualXFBList.begin(), m_virtualXFBList.end(),
                      [srcLower, srcUpper](const VirtualXFB& xfb) {
                        const u32 dstLower = xfb.xfbAddr;
                        const u32 dstUpper = xfb.xfbAddr + 2 * xfb.xfbWidth * xfb.xfbHeight;

                        return dstLower >= srcLower && dstUpper <= srcUpper;
                      });
}

void FramebufferManagerBase::ReplaceVirtualXFB()
{
  VirtualXFBListType::iterator it = m_virtualXFBList.begin();

  const s32 srcLower = it->xfbAddr;
  const s32 srcUpper = it->xfbAddr + 2 * it->xfbWidth * it->xfbHeight;
  const s32 lineSize = 2 * it->xfbWidth;

  ++it;

  for (; it != m_virtualXFBList.end(); ++it)
  {
    s32 dstLower = it->xfbAddr;
    s32 dstUpper = it->xfbAddr + 2 * it->xfbWidth * it->xfbHeight;

    if (dstLower >= srcLower && dstUpper <= srcUpper)
    {
      // Invalidate the data
      it->xfbAddr = 0;
      it->xfbHeight = 0;
      it->xfbWidth = 0;
    }
    else if (AddressRangesOverlap(srcLower, srcUpper, dstLower, dstUpper))
    {
      s32 upperOverlap = (srcUpper - dstLower) / lineSize;
      s32 lowerOverlap = (dstUpper - srcLower) / lineSize;

      if (upperOverlap > 0 && lowerOverlap < 0)
      {
        it->xfbAddr += lineSize * upperOverlap;
        it->xfbHeight -= upperOverlap;
      }
      else if (lowerOverlap > 0)
      {
        it->xfbHeight -= lowerOverlap;
      }
    }
  }
}