// Copyright 2008 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include <cmath>
#include <cstring>

#include "Common/Assert.h"
#include "Common/CommonTypes.h"
#include "VideoCommon/BPMemory.h"
#include "VideoCommon/LightingShaderGen.h"
#include "VideoCommon/NativeVertexFormat.h"
#include "VideoCommon/VertexLoaderManager.h"
#include "VideoCommon/VertexShaderGen.h"
#include "VideoCommon/VideoConfig.h"

VertexShaderUid GetVertexShaderUid()
{
  VertexShaderUid out;
  vertex_shader_uid_data* uid_data = out.GetUidData<vertex_shader_uid_data>();
  memset(uid_data, 0, sizeof(*uid_data));

  _assert_(bpmem.genMode.numtexgens == xfmem.numTexGen.numTexGens);
  _assert_(bpmem.genMode.numcolchans == xfmem.numChan.numColorChans);

  uid_data->numTexGens = xfmem.numTexGen.numTexGens;
  uid_data->components = VertexLoaderManager::g_current_components;
  uid_data->pixel_lighting = g_ActiveConfig.bEnablePixelLighting;
  uid_data->msaa = g_ActiveConfig.iMultisamples > 1;
  uid_data->ssaa = g_ActiveConfig.iMultisamples > 1 && g_ActiveConfig.bSSAA;
  uid_data->numColorChans = xfmem.numChan.numColorChans;

  GetLightingShaderUid(uid_data->lighting);

  // transform texcoords
  for (unsigned int i = 0; i < uid_data->numTexGens; ++i)
  {
    auto& texinfo = uid_data->texMtxInfo[i];

    texinfo.sourcerow = xfmem.texMtxInfo[i].sourcerow;
    texinfo.texgentype = xfmem.texMtxInfo[i].texgentype;
    texinfo.inputform = xfmem.texMtxInfo[i].inputform;

    // first transformation
    switch (texinfo.texgentype)
    {
    case XF_TEXGEN_EMBOSS_MAP:  // calculate tex coords into bump map
      if (uid_data->components & (VB_HAS_NRM1 | VB_HAS_NRM2))
      {
        // transform the light dir into tangent space
        texinfo.embosslightshift = xfmem.texMtxInfo[i].embosslightshift;
        texinfo.embosssourceshift = xfmem.texMtxInfo[i].embosssourceshift;
      }
      else
      {
        texinfo.embosssourceshift = xfmem.texMtxInfo[i].embosssourceshift;
      }
      break;
    case XF_TEXGEN_COLOR_STRGBC0:
    case XF_TEXGEN_COLOR_STRGBC1:
      break;
    case XF_TEXGEN_REGULAR:
    default:
      uid_data->texMtxInfo_n_projection |= xfmem.texMtxInfo[i].projection << i;
      break;
    }

    uid_data->dualTexTrans_enabled = xfmem.dualTexTrans.enabled;
    // CHECKME: does this only work for regular tex gen types?
    if (uid_data->dualTexTrans_enabled && texinfo.texgentype == XF_TEXGEN_REGULAR)
    {
      auto& postInfo = uid_data->postMtxInfo[i];
      postInfo.index = xfmem.postMtxInfo[i].index;
      postInfo.normalize = xfmem.postMtxInfo[i].normalize;
    }
  }

  return out;
}

ShaderCode GenerateVertexShaderCode(API_TYPE api_type, const vertex_shader_uid_data* uid_data)
{
  ShaderCode out;
  out.Write("%s", s_lighting_struct);

  // uniforms
  if (api_type == API_OPENGL)
    out.Write("layout(std140%s) uniform VSBlock {\n",
              g_ActiveConfig.backend_info.bSupportsBindingLayout ? ", binding = 2" : "");
  else
    out.Write("cbuffer VSBlock {\n");
  out.Write(s_shader_uniforms);
  out.Write("};\n");

  out.Write("struct VS_OUTPUT {\n");
  GenerateVSOutputMembers(out, api_type, uid_data->numTexGens, uid_data->pixel_lighting, "");
  out.Write("};\n");

  if (api_type == API_OPENGL)
  {
    out.Write("in float4 rawpos; // ATTR%d,\n", SHADER_POSITION_ATTRIB);
    if (uid_data->components & VB_HAS_POSMTXIDX)
      out.Write("in int posmtx; // ATTR%d,\n", SHADER_POSMTX_ATTRIB);
    if (uid_data->components & VB_HAS_NRM0)
      out.Write("in float3 rawnorm0; // ATTR%d,\n", SHADER_NORM0_ATTRIB);
    if (uid_data->components & VB_HAS_NRM1)
      out.Write("in float3 rawnorm1; // ATTR%d,\n", SHADER_NORM1_ATTRIB);
    if (uid_data->components & VB_HAS_NRM2)
      out.Write("in float3 rawnorm2; // ATTR%d,\n", SHADER_NORM2_ATTRIB);

    if (uid_data->components & VB_HAS_COL0)
      out.Write("in float4 color0; // ATTR%d,\n", SHADER_COLOR0_ATTRIB);
    if (uid_data->components & VB_HAS_COL1)
      out.Write("in float4 color1; // ATTR%d,\n", SHADER_COLOR1_ATTRIB);

    for (int i = 0; i < 8; ++i)
    {
      u32 hastexmtx = (uid_data->components & (VB_HAS_TEXMTXIDX0 << i));
      if ((uid_data->components & (VB_HAS_UV0 << i)) || hastexmtx)
        out.Write("in float%d tex%d; // ATTR%d,\n", hastexmtx ? 3 : 2, i,
                  SHADER_TEXTURE0_ATTRIB + i);
    }

    if (g_ActiveConfig.backend_info.bSupportsGeometryShaders)
    {
      out.Write("out VertexData {\n");
      GenerateVSOutputMembers(
          out, api_type, uid_data->numTexGens, uid_data->pixel_lighting,
          GetInterpolationQualifier(uid_data->msaa, uid_data->ssaa, false, true));
      out.Write("} vs;\n");
    }
    else
    {
      // Let's set up attributes
      for (u32 i = 0; i < 8; ++i)
      {
        if (i < uid_data->numTexGens)
        {
          out.Write("%s out float3 uv%u;\n",
                    GetInterpolationQualifier(uid_data->msaa, uid_data->ssaa), i);
        }
      }
      out.Write("%s out float4 clipPos;\n",
                GetInterpolationQualifier(uid_data->msaa, uid_data->ssaa));
      if (uid_data->pixel_lighting)
      {
        out.Write("%s out float3 Normal;\n",
                  GetInterpolationQualifier(uid_data->msaa, uid_data->ssaa));
        out.Write("%s out float3 WorldPos;\n",
                  GetInterpolationQualifier(uid_data->msaa, uid_data->ssaa));
      }
      out.Write("%s out float4 colors_0;\n",
                GetInterpolationQualifier(uid_data->msaa, uid_data->ssaa));
      out.Write("%s out float4 colors_1;\n",
                GetInterpolationQualifier(uid_data->msaa, uid_data->ssaa));
    }

    out.Write("void main()\n{\n");
  }
  else  // D3D
  {
    out.Write("VS_OUTPUT main(\n");

    // inputs
    if (uid_data->components & VB_HAS_NRM0)
      out.Write("  float3 rawnorm0 : NORMAL0,\n");
    if (uid_data->components & VB_HAS_NRM1)
      out.Write("  float3 rawnorm1 : NORMAL1,\n");
    if (uid_data->components & VB_HAS_NRM2)
      out.Write("  float3 rawnorm2 : NORMAL2,\n");
    if (uid_data->components & VB_HAS_COL0)
      out.Write("  float4 color0 : COLOR0,\n");
    if (uid_data->components & VB_HAS_COL1)
      out.Write("  float4 color1 : COLOR1,\n");
    for (int i = 0; i < 8; ++i)
    {
      u32 hastexmtx = (uid_data->components & (VB_HAS_TEXMTXIDX0 << i));
      if ((uid_data->components & (VB_HAS_UV0 << i)) || hastexmtx)
        out.Write("  float%d tex%d : TEXCOORD%d,\n", hastexmtx ? 3 : 2, i, i);
    }
    if (uid_data->components & VB_HAS_POSMTXIDX)
      out.Write("  int posmtx : BLENDINDICES,\n");
    out.Write("  float4 rawpos : POSITION) {\n");
  }

  out.Write("VS_OUTPUT o;\n");

  // transforms
  if (uid_data->components & VB_HAS_POSMTXIDX)
  {
    out.Write("float4 pos = float4(dot(" I_TRANSFORMMATRICES
              "[posmtx], rawpos), dot(" I_TRANSFORMMATRICES
              "[posmtx+1], rawpos), dot(" I_TRANSFORMMATRICES "[posmtx+2], rawpos), 1);\n");

    if (uid_data->components & VB_HAS_NRMALL)
    {
      out.Write("int normidx = posmtx & 31;\n");
      out.Write("float3 N0 = " I_NORMALMATRICES "[normidx].xyz, N1 = " I_NORMALMATRICES
                "[normidx+1].xyz, N2 = " I_NORMALMATRICES "[normidx+2].xyz;\n");
    }

    if (uid_data->components & VB_HAS_NRM0)
      out.Write("float3 _norm0 = normalize(float3(dot(N0, rawnorm0), dot(N1, rawnorm0), dot(N2, "
                "rawnorm0)));\n");
    if (uid_data->components & VB_HAS_NRM1)
      out.Write(
          "float3 _norm1 = float3(dot(N0, rawnorm1), dot(N1, rawnorm1), dot(N2, rawnorm1));\n");
    if (uid_data->components & VB_HAS_NRM2)
      out.Write(
          "float3 _norm2 = float3(dot(N0, rawnorm2), dot(N1, rawnorm2), dot(N2, rawnorm2));\n");
  }
  else
  {
    out.Write("float4 pos = float4(dot(" I_POSNORMALMATRIX "[0], rawpos), dot(" I_POSNORMALMATRIX
              "[1], rawpos), dot(" I_POSNORMALMATRIX "[2], rawpos), 1.0);\n");
    if (uid_data->components & VB_HAS_NRM0)
      out.Write("float3 _norm0 = normalize(float3(dot(" I_POSNORMALMATRIX
                "[3].xyz, rawnorm0), dot(" I_POSNORMALMATRIX
                "[4].xyz, rawnorm0), dot(" I_POSNORMALMATRIX "[5].xyz, rawnorm0)));\n");
    if (uid_data->components & VB_HAS_NRM1)
      out.Write("float3 _norm1 = float3(dot(" I_POSNORMALMATRIX
                "[3].xyz, rawnorm1), dot(" I_POSNORMALMATRIX
                "[4].xyz, rawnorm1), dot(" I_POSNORMALMATRIX "[5].xyz, rawnorm1));\n");
    if (uid_data->components & VB_HAS_NRM2)
      out.Write("float3 _norm2 = float3(dot(" I_POSNORMALMATRIX
                "[3].xyz, rawnorm2), dot(" I_POSNORMALMATRIX
                "[4].xyz, rawnorm2), dot(" I_POSNORMALMATRIX "[5].xyz, rawnorm2));\n");
  }

  if (!(uid_data->components & VB_HAS_NRM0))
    out.Write("float3 _norm0 = float3(0.0, 0.0, 0.0);\n");

  out.Write("o.pos = float4(dot(" I_PROJECTION "[0], pos), dot(" I_PROJECTION
            "[1], pos), dot(" I_PROJECTION "[2], pos), dot(" I_PROJECTION "[3], pos));\n");

  out.Write("int4 lacc;\n"
            "float3 ldir, h, cosAttn, distAttn;\n"
            "float dist, dist2, attn;\n");

  if (uid_data->numColorChans == 0)
  {
    if (uid_data->components & VB_HAS_COL0)
      out.Write("o.colors_0 = color0;\n");
    else
      out.Write("o.colors_0 = float4(1.0, 1.0, 1.0, 1.0);\n");
  }

  GenerateLightingShaderCode(out, uid_data->lighting, uid_data->components, "color", "o.colors_");

  if (uid_data->numColorChans < 2)
  {
    if (uid_data->components & VB_HAS_COL1)
      out.Write("o.colors_1 = color1;\n");
    else
      out.Write("o.colors_1 = o.colors_0;\n");
  }

  // transform texcoords
  out.Write("float4 coord = float4(0.0, 0.0, 1.0, 1.0);\n");
  for (unsigned int i = 0; i < uid_data->numTexGens; ++i)
  {
    auto& texinfo = uid_data->texMtxInfo[i];

    out.Write("{\n");
    out.Write("coord = float4(0.0, 0.0, 1.0, 1.0);\n");
    switch (texinfo.sourcerow)
    {
    case XF_SRCGEOM_INROW:
      out.Write("coord.xyz = rawpos.xyz;\n");
      break;
    case XF_SRCNORMAL_INROW:
      if (uid_data->components & VB_HAS_NRM0)
      {
        out.Write("coord.xyz = rawnorm0.xyz;\n");
      }
      break;
    case XF_SRCCOLORS_INROW:
      _assert_(texinfo.texgentype == XF_TEXGEN_COLOR_STRGBC0 ||
               texinfo.texgentype == XF_TEXGEN_COLOR_STRGBC1);
      break;
    case XF_SRCBINORMAL_T_INROW:
      if (uid_data->components & VB_HAS_NRM1)
      {
        out.Write("coord.xyz = rawnorm1.xyz;\n");
      }
      break;
    case XF_SRCBINORMAL_B_INROW:
      if (uid_data->components & VB_HAS_NRM2)
      {
        out.Write("coord.xyz = rawnorm2.xyz;\n");
      }
      break;
    default:
      _assert_(texinfo.sourcerow <= XF_SRCTEX7_INROW);
      if (uid_data->components & (VB_HAS_UV0 << (texinfo.sourcerow - XF_SRCTEX0_INROW)))
        out.Write("coord = float4(tex%d.x, tex%d.y, 1.0, 1.0);\n",
                  texinfo.sourcerow - XF_SRCTEX0_INROW, texinfo.sourcerow - XF_SRCTEX0_INROW);
      break;
    }
    // Input form of AB11 sets z element to 1.0

    if (texinfo.inputform == XF_TEXINPUT_AB11)
      out.Write("coord.z = 1.0;\n");

    // first transformation
    switch (texinfo.texgentype)
    {
    case XF_TEXGEN_EMBOSS_MAP:  // calculate tex coords into bump map

      if (uid_data->components & (VB_HAS_NRM1 | VB_HAS_NRM2))
      {
        // transform the light dir into tangent space
        out.Write("ldir = normalize(" LIGHT_POS ".xyz - pos.xyz);\n",
                  LIGHT_POS_PARAMS(texinfo.embosslightshift));
        out.Write(
            "o.tex%d.xyz = o.tex%d.xyz + float3(dot(ldir, _norm1), dot(ldir, _norm2), 0.0);\n", i,
            texinfo.embosssourceshift);
      }
      else
      {
        // The following assert was triggered in House of the Dead Overkill and Star Wars Rogue
        // Squadron 2
        //_assert_(0); // should have normals
        out.Write("o.tex%d.xyz = o.tex%d.xyz;\n", i, texinfo.embosssourceshift);
      }

      break;
    case XF_TEXGEN_COLOR_STRGBC0:
      out.Write("o.tex%d.xyz = float3(o.colors_0.x, o.colors_0.y, 1);\n", i);
      break;
    case XF_TEXGEN_COLOR_STRGBC1:
      out.Write("o.tex%d.xyz = float3(o.colors_1.x, o.colors_1.y, 1);\n", i);
      break;
    case XF_TEXGEN_REGULAR:
    default:
      if (uid_data->components & (VB_HAS_TEXMTXIDX0 << i))
      {
        out.Write("int tmp = int(tex%d.z);\n", i);
        if (((uid_data->texMtxInfo_n_projection >> i) & 1) == XF_TEXPROJ_STQ)
          out.Write("o.tex%d.xyz = float3(dot(coord, " I_TRANSFORMMATRICES
                    "[tmp]), dot(coord, " I_TRANSFORMMATRICES
                    "[tmp+1]), dot(coord, " I_TRANSFORMMATRICES "[tmp+2]));\n",
                    i);
        else
          out.Write("o.tex%d.xyz = float3(dot(coord, " I_TRANSFORMMATRICES
                    "[tmp]), dot(coord, " I_TRANSFORMMATRICES "[tmp+1]), 1);\n",
                    i);
      }
      else
      {
        if (((uid_data->texMtxInfo_n_projection >> i) & 1) == XF_TEXPROJ_STQ)
          out.Write("o.tex%d.xyz = float3(dot(coord, " I_TEXMATRICES
                    "[%d]), dot(coord, " I_TEXMATRICES "[%d]), dot(coord, " I_TEXMATRICES
                    "[%d]));\n",
                    i, 3 * i, 3 * i + 1, 3 * i + 2);
        else
          out.Write("o.tex%d.xyz = float3(dot(coord, " I_TEXMATRICES
                    "[%d]), dot(coord, " I_TEXMATRICES "[%d]), 1);\n",
                    i, 3 * i, 3 * i + 1);
      }
      break;
    }

    // CHECKME: does this only work for regular tex gen types?
    if (uid_data->dualTexTrans_enabled && texinfo.texgentype == XF_TEXGEN_REGULAR)
    {
      auto& postInfo = uid_data->postMtxInfo[i];

      out.Write("float4 P0 = " I_POSTTRANSFORMMATRICES "[%d];\n"
                "float4 P1 = " I_POSTTRANSFORMMATRICES "[%d];\n"
                "float4 P2 = " I_POSTTRANSFORMMATRICES "[%d];\n",
                postInfo.index & 0x3f, (postInfo.index + 1) & 0x3f, (postInfo.index + 2) & 0x3f);

      if (postInfo.normalize)
        out.Write("o.tex%d.xyz = normalize(o.tex%d.xyz);\n", i, i);

      // multiply by postmatrix
      out.Write("o.tex%d.xyz = float3(dot(P0.xyz, o.tex%d.xyz) + P0.w, dot(P1.xyz, o.tex%d.xyz) + "
                "P1.w, dot(P2.xyz, o.tex%d.xyz) + P2.w);\n",
                i, i, i, i);
    }

    out.Write("}\n");
  }

  // clipPos/w needs to be done in pixel shader, not here
  out.Write("o.clipPos = o.pos;\n");

  if (uid_data->pixel_lighting)
  {
    out.Write("o.Normal = _norm0;\n");
    out.Write("o.WorldPos = pos.xyz;\n");

    if (uid_data->components & VB_HAS_COL0)
      out.Write("o.colors_0 = color0;\n");

    if (uid_data->components & VB_HAS_COL1)
      out.Write("o.colors_1 = color1;\n");
  }

  // write the true depth value, if the game uses depth textures pixel shaders will override with
  // the correct values
  // if not early z culling will improve speed
  if (g_ActiveConfig.backend_info.bSupportsClipControl)
  {
    out.Write("o.pos.z = -o.pos.z;\n");
  }
  else  // OGL
  {
    // this results in a scale from -1..0 to -1..1 after perspective
    // divide
    out.Write("o.pos.z = o.pos.z * -2.0 - o.pos.w;\n");

    // the next steps of the OGL pipeline are:
    // (x_c,y_c,z_c,w_c) = o.pos  //switch to OGL spec terminology
    // clipping to -w_c <= (x_c,y_c,z_c) <= w_c
    // (x_d,y_d,z_d) = (x_c,y_c,z_c)/w_c//perspective divide
    // z_w = (f-n)/2*z_d + (n+f)/2
    // z_w now contains the value to go to the 0..1 depth buffer

    // trying to get the correct semantic while not using glDepthRange
    // seems to get rather complicated
  }

  // The console GPU places the pixel center at 7/12 in screen space unless
  // antialiasing is enabled, while D3D and OpenGL place it at 0.5. This results
  // in some primitives being placed one pixel too far to the bottom-right,
  // which in turn can be critical if it happens for clear quads.
  // Hence, we compensate for this pixel center difference so that primitives
  // get rasterized correctly.
  out.Write("o.pos.xy = o.pos.xy - o.pos.w * " I_PIXELCENTERCORRECTION ".xy;\n");

  if (api_type == API_OPENGL)
  {
    if (g_ActiveConfig.backend_info.bSupportsGeometryShaders)
    {
      AssignVSOutputMembers(out, "vs", "o", uid_data->numTexGens, uid_data->pixel_lighting);
    }
    else
    {
      // TODO: Pass interface blocks between shader stages even if geometry shaders
      // are not supported, however that will require at least OpenGL 3.2 support.
      for (unsigned int i = 0; i < uid_data->numTexGens; ++i)
        out.Write("uv%d.xyz = o.tex%d;\n", i, i);
      out.Write("clipPos = o.clipPos;\n");
      if (uid_data->pixel_lighting)
      {
        out.Write("Normal = o.Normal;\n");
        out.Write("WorldPos = o.WorldPos;\n");
      }
      out.Write("colors_0 = o.colors_0;\n");
      out.Write("colors_1 = o.colors_1;\n");
    }

    out.Write("gl_Position = o.pos;\n");
  }
  else  // D3D
  {
    out.Write("return o;\n");
  }
  out.Write("}\n");

  return out;
}
