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

#include <memory>

#include "Common/BitSet.h"
#include "Common/ChunkFile.h"
#include "Common/CommonTypes.h"
#include "Common/Logging/Log.h"

#include "VideoCommon/BPMemory.h"
#include "VideoCommon/DataReader.h"
#include "VideoCommon/Debugger.h"
#include "VideoCommon/GeometryShaderManager.h"
#include "VideoCommon/IndexGenerator.h"
#include "VideoCommon/NativeVertexFormat.h"
#include "VideoCommon/OpcodeDecoding.h"
#include "VideoCommon/PerfQueryBase.h"
#include "VideoCommon/PixelShaderManager.h"
#include "VideoCommon/RenderBase.h"
#include "VideoCommon/TextureCacheBase.h"
#include "VideoCommon/VertexLoaderManager.h"
#include "VideoCommon/VertexManagerBase.h"
#include "VideoCommon/VertexShaderManager.h"
#include "VideoCommon/VideoConfig.h"
#include "VideoCommon/XFMemory.h"

std::unique_ptr<VertexManagerBase> g_vertex_manager;

u8* VertexManagerBase::s_pCurBufferPointer;
u8* VertexManagerBase::s_pBaseBufferPointer;
u8* VertexManagerBase::s_pEndBufferPointer;

PrimitiveType VertexManagerBase::current_primitive_type;

Slope VertexManagerBase::s_zslope;

bool VertexManagerBase::s_is_flushed;
bool VertexManagerBase::s_cull_all;

static const PrimitiveType primitive_from_gx[8] = {
    PRIMITIVE_TRIANGLES,  // GX_DRAW_QUADS
    PRIMITIVE_TRIANGLES,  // GX_DRAW_QUADS_2
    PRIMITIVE_TRIANGLES,  // GX_DRAW_TRIANGLES
    PRIMITIVE_TRIANGLES,  // GX_DRAW_TRIANGLE_STRIP
    PRIMITIVE_TRIANGLES,  // GX_DRAW_TRIANGLE_FAN
    PRIMITIVE_LINES,      // GX_DRAW_LINES
    PRIMITIVE_LINES,      // GX_DRAW_LINE_STRIP
    PRIMITIVE_POINTS,     // GX_DRAW_POINTS
};

VertexManagerBase::VertexManagerBase()
{
  s_is_flushed = true;
  s_cull_all = false;
}

VertexManagerBase::~VertexManagerBase()
{
}

u32 VertexManagerBase::GetRemainingSize()
{
  return (u32)(s_pEndBufferPointer - s_pCurBufferPointer);
}

DataReader VertexManagerBase::PrepareForAdditionalData(int primitive, u32 count, u32 stride,
                                                       bool cullall)
{
  // The SSE vertex loader can write up to 4 bytes past the end
  u32 const needed_vertex_bytes = count * stride + 4;

  // We can't merge different kinds of primitives, so we have to flush here
  if (current_primitive_type != primitive_from_gx[primitive])
    Flush();
  current_primitive_type = primitive_from_gx[primitive];

  // Check for size in buffer, if the buffer gets full, call Flush()
  if (!s_is_flushed &&
      (count > IndexGenerator::GetRemainingIndices() || count > GetRemainingIndices(primitive) ||
       needed_vertex_bytes > GetRemainingSize()))
  {
    Flush();

    if (count > IndexGenerator::GetRemainingIndices())
      ERROR_LOG(VIDEO, "Too little remaining index values. Use 32-bit or reset them on flush.");
    if (count > GetRemainingIndices(primitive))
      ERROR_LOG(VIDEO, "VertexManager: Buffer not large enough for all indices! "
                       "Increase MAXIBUFFERSIZE or we need primitive breaking after all.");
    if (needed_vertex_bytes > GetRemainingSize())
      ERROR_LOG(VIDEO, "VertexManager: Buffer not large enough for all vertices! "
                       "Increase MAXVBUFFERSIZE or we need primitive breaking after all.");
  }

  s_cull_all = cullall;

  // need to alloc new buffer
  if (s_is_flushed)
  {
    g_vertex_manager->ResetBuffer(stride);
    s_is_flushed = false;
  }

  return DataReader(s_pCurBufferPointer, s_pEndBufferPointer);
}

void VertexManagerBase::FlushData(u32 count, u32 stride)
{
  s_pCurBufferPointer += count * stride;
}

u32 VertexManagerBase::GetRemainingIndices(int primitive)
{
  u32 index_len = MAXIBUFFERSIZE - IndexGenerator::GetIndexLen();

  if (g_Config.backend_info.bSupportsPrimitiveRestart)
  {
    switch (primitive)
    {
    case GX_DRAW_QUADS:
    case GX_DRAW_QUADS_2:
      return index_len / 5 * 4;
    case GX_DRAW_TRIANGLES:
      return index_len / 4 * 3;
    case GX_DRAW_TRIANGLE_STRIP:
      return index_len / 1 - 1;
    case GX_DRAW_TRIANGLE_FAN:
      return index_len / 6 * 4 + 1;

    case GX_DRAW_LINES:
      return index_len;
    case GX_DRAW_LINE_STRIP:
      return index_len / 2 + 1;

    case GX_DRAW_POINTS:
      return index_len;

    default:
      return 0;
    }
  }
  else
  {
    switch (primitive)
    {
    case GX_DRAW_QUADS:
    case GX_DRAW_QUADS_2:
      return index_len / 6 * 4;
    case GX_DRAW_TRIANGLES:
      return index_len;
    case GX_DRAW_TRIANGLE_STRIP:
      return index_len / 3 + 2;
    case GX_DRAW_TRIANGLE_FAN:
      return index_len / 3 + 2;

    case GX_DRAW_LINES:
      return index_len;
    case GX_DRAW_LINE_STRIP:
      return index_len / 2 + 1;

    case GX_DRAW_POINTS:
      return index_len;

    default:
      return 0;
    }
  }
}

void VertexManagerBase::Flush()
{
  if (s_is_flushed)
    return;

  // loading a state will invalidate BP, so check for it
  g_video_backend->CheckInvalidState();

#if defined(_DEBUG) || defined(DEBUGFAST)
  PRIM_LOG("frame%d:\n texgen=%d, numchan=%d, dualtex=%d, ztex=%d, cole=%d, alpe=%d, ze=%d",
           g_ActiveConfig.iSaveTargetId, xfmem.numTexGen.numTexGens, xfmem.numChan.numColorChans,
           xfmem.dualTexTrans.enabled, bpmem.ztex2.op, (int)bpmem.blendmode.colorupdate,
           (int)bpmem.blendmode.alphaupdate, (int)bpmem.zmode.updateenable);

  for (unsigned int i = 0; i < xfmem.numChan.numColorChans; ++i)
  {
    LitChannel* ch = &xfmem.color[i];
    PRIM_LOG("colchan%d: matsrc=%d, light=0x%x, ambsrc=%d, diffunc=%d, attfunc=%d", i,
             ch->matsource, ch->GetFullLightMask(), ch->ambsource, ch->diffusefunc, ch->attnfunc);
    ch = &xfmem.alpha[i];
    PRIM_LOG("alpchan%d: matsrc=%d, light=0x%x, ambsrc=%d, diffunc=%d, attfunc=%d", i,
             ch->matsource, ch->GetFullLightMask(), ch->ambsource, ch->diffusefunc, ch->attnfunc);
  }

  for (unsigned int i = 0; i < xfmem.numTexGen.numTexGens; ++i)
  {
    TexMtxInfo tinfo = xfmem.texMtxInfo[i];
    if (tinfo.texgentype != XF_TEXGEN_EMBOSS_MAP)
      tinfo.hex &= 0x7ff;
    if (tinfo.texgentype != XF_TEXGEN_REGULAR)
      tinfo.projection = 0;

    PRIM_LOG("txgen%d: proj=%d, input=%d, gentype=%d, srcrow=%d, embsrc=%d, emblght=%d, "
             "postmtx=%d, postnorm=%d",
             i, tinfo.projection, tinfo.inputform, tinfo.texgentype, tinfo.sourcerow,
             tinfo.embosssourceshift, tinfo.embosslightshift, xfmem.postMtxInfo[i].index,
             xfmem.postMtxInfo[i].normalize);
  }

  PRIM_LOG("pixel: tev=%d, ind=%d, texgen=%d, dstalpha=%d, alphatest=0x%x",
           (int)bpmem.genMode.numtevstages + 1, (int)bpmem.genMode.numindstages,
           (int)bpmem.genMode.numtexgens, (u32)bpmem.dstalpha.enable,
           (bpmem.alpha_test.hex >> 16) & 0xff);
#endif

  // If the primitave is marked CullAll. All we need to do is update the vertex constants and
  // calculate the zfreeze refrence slope
  if (!s_cull_all)
  {
    BitSet32 usedtextures;
    for (u32 i = 0; i < bpmem.genMode.numtevstages + 1u; ++i)
      if (bpmem.tevorders[i / 2].getEnable(i & 1))
        usedtextures[bpmem.tevorders[i / 2].getTexMap(i & 1)] = true;

    if (bpmem.genMode.numindstages > 0)
      for (unsigned int i = 0; i < bpmem.genMode.numtevstages + 1u; ++i)
        if (bpmem.tevind[i].IsActive() && bpmem.tevind[i].bt < bpmem.genMode.numindstages)
          usedtextures[bpmem.tevindref.getTexMap(bpmem.tevind[i].bt)] = true;

    TextureCacheBase::UnbindTextures();
    for (unsigned int i : usedtextures)
    {
      const TextureCacheBase::TCacheEntryBase* tentry = TextureCacheBase::Load(i);

      if (tentry)
      {
        g_renderer->SetSamplerState(i & 3, i >> 2, tentry->is_custom_tex);
        PixelShaderManager::SetTexDims(i, tentry->native_width, tentry->native_height);
      }
      else
      {
        ERROR_LOG(VIDEO, "error loading texture");
      }
    }
    g_texture_cache->BindTextures();
  }

  // set global vertex constants
  VertexShaderManager::SetConstants();

  // Calculate ZSlope for zfreeze
  if (!bpmem.genMode.zfreeze)
  {
    // Must be done after VertexShaderManager::SetConstants()
    CalculateZSlope(VertexLoaderManager::GetCurrentVertexFormat());
  }
  else if (s_zslope.dirty && !s_cull_all)  // or apply any dirty ZSlopes
  {
    PixelShaderManager::SetZSlope(s_zslope.dfdx, s_zslope.dfdy, s_zslope.f0);
    s_zslope.dirty = false;
  }

  if (!s_cull_all)
  {
    // set the rest of the global constants
    GeometryShaderManager::SetConstants();
    PixelShaderManager::SetConstants();

    bool useDstAlpha = bpmem.dstalpha.enable && bpmem.blendmode.alphaupdate &&
                       bpmem.zcontrol.pixel_format == PEControl::RGBA6_Z24;

    if (PerfQueryBase::ShouldEmulate())
      g_perf_query->EnableQuery(bpmem.zcontrol.early_ztest ? PQG_ZCOMP_ZCOMPLOC : PQG_ZCOMP);
    g_vertex_manager->vFlush(useDstAlpha);
    if (PerfQueryBase::ShouldEmulate())
      g_perf_query->DisableQuery(bpmem.zcontrol.early_ztest ? PQG_ZCOMP_ZCOMPLOC : PQG_ZCOMP);
  }

  GFX_DEBUGGER_PAUSE_AT(NEXT_FLUSH, true);

  if (xfmem.numTexGen.numTexGens != bpmem.genMode.numtexgens)
    ERROR_LOG(VIDEO,
              "xf.numtexgens (%d) does not match bp.numtexgens (%d). Error in command stream.",
              xfmem.numTexGen.numTexGens, bpmem.genMode.numtexgens.Value());

  s_is_flushed = true;
  s_cull_all = false;
}

void VertexManagerBase::DoState(PointerWrap& p)
{
  p.Do(s_zslope);
  g_vertex_manager->vDoState(p);
}

void VertexManagerBase::CalculateZSlope(NativeVertexFormat* format)
{
  float out[12];
  float viewOffset[2] = {xfmem.viewport.xOrig - bpmem.scissorOffset.x * 2,
                         xfmem.viewport.yOrig - bpmem.scissorOffset.y * 2};

  if (current_primitive_type != PRIMITIVE_TRIANGLES)
    return;

  // Global matrix ID.
  u32 mtxIdx = g_main_cp_state.matrix_index_a.PosNormalMtxIdx;
  const PortableVertexDeclaration vert_decl = format->GetVertexDeclaration();

  // Make sure the buffer contains at least 3 vertices.
  if ((s_pCurBufferPointer - s_pBaseBufferPointer) < (vert_decl.stride * 3))
    return;

  // Lookup vertices of the last rendered triangle and software-transform them
  // This allows us to determine the depth slope, which will be used if z-freeze
  // is enabled in the following flush.
  for (unsigned int i = 0; i < 3; ++i)
  {
    // If this vertex format has per-vertex position matrix IDs, look it up.
    if (vert_decl.posmtx.enable)
      mtxIdx = VertexLoaderManager::position_matrix_index[2 - i];

    if (vert_decl.position.components == 2)
      VertexLoaderManager::position_cache[2 - i][2] = 0;

    VertexShaderManager::TransformToClipSpace(&VertexLoaderManager::position_cache[2 - i][0],
                                              &out[i * 4], mtxIdx);

    // Transform to Screenspace
    float inv_w = 1.0f / out[3 + i * 4];

    out[0 + i * 4] = out[0 + i * 4] * inv_w * xfmem.viewport.wd + viewOffset[0];
    out[1 + i * 4] = out[1 + i * 4] * inv_w * xfmem.viewport.ht + viewOffset[1];
    out[2 + i * 4] = out[2 + i * 4] * inv_w * xfmem.viewport.zRange + xfmem.viewport.farZ;
  }

  float dx31 = out[8] - out[0];
  float dx12 = out[0] - out[4];
  float dy12 = out[1] - out[5];
  float dy31 = out[9] - out[1];

  float DF31 = out[10] - out[2];
  float DF21 = out[6] - out[2];
  float a = DF31 * -dy12 - DF21 * dy31;
  float b = dx31 * DF21 + dx12 * DF31;
  float c = -dx12 * dy31 - dx31 * -dy12;

  // Sometimes we process de-generate triangles. Stop any divide by zeros
  if (c == 0)
    return;

  s_zslope.dfdx = -a / c;
  s_zslope.dfdy = -b / c;
  s_zslope.f0 = out[2] - (out[0] * s_zslope.dfdx + out[1] * s_zslope.dfdy);
  s_zslope.dirty = true;
}
