#include "Client/Application/ErrorDialog.h"
#include "Render/DX7/RendererFogDX7.h"

#include <bit>
#include <cmath>

namespace {
  // OFFSET: 0x00556E50
  // FUNCTION: fn_02039
  float Sine(float angle) {
    return static_cast<float>(std::sin(static_cast<double>(angle)));
  }

  // OFFSET: 0x00556E40
  // FUNCTION: fn_02038
  float Cosine(float angle) {
    return static_cast<float>(std::cos(static_cast<double>(angle)));
  }
}

// OFFSET: 0x00556E60
// FUNCTION: fn_02040
float SquareRoot(float value) {
  return std::sqrt(value);
}

// OFFSET: 0x00548C30
// FUNCTION: fn_01863
HRESULT PerspectiveMatrixDX7(D3DMATRIX& matrix, float fov, float aspect, float nearPlane, float farPlane) {
  const float difference = farPlane - nearPlane;
  constexpr float epsilon = 0.01f;

  if (epsilon > std::fabs(difference)) {
    return E_INVALIDARG;
  }

  const float half = fov * 0.5f;

  if (epsilon > std::fabs(Sine(half))) {
    return E_INVALIDARG;
  }

  const float cosineX = Cosine(half);
  const float sineX = Sine(half);
  const float scaleX = static_cast<float>((static_cast<double>(cosineX) / sineX) * aspect);
  const float cosineY = Cosine(half);
  const float sineY = Sine(half);
  const float scaleY = static_cast<float>(static_cast<double>(cosineY) / sineY);
  const float depth = farPlane / difference;

  matrix._12 = matrix._13 = matrix._14 = 0;
  matrix._21 = matrix._23 = matrix._24 = 0;
  matrix._31 = matrix._32 = 0;
  matrix._41 = matrix._42 = matrix._44 = 0;
  matrix._34 = 1;
  matrix._33 = depth;
  const float translation = -depth * nearPlane;
  matrix._11 = scaleX;
  matrix._22 = scaleY;
  matrix._43 = translation;

  return S_OK;
}

// OFFSET: 0x0055CF10
// FUNCTION: fn_02094
void RendererFogDX7::Set(int value, IDirect3DDevice7* device, const D3DDEVICEDESC7& caps, FogConfiguration& configuration) {
  this->supported = (caps.dpcTriCaps.dwRasterCaps & D3DPRASTERCAPS_FOGVERTEX) != 0;
  this->enabled = value;
  device->SetRenderState(D3DRENDERSTATE_FOGENABLE, value);
  this->dirty = 1;
  configuration.range = 1;
  configuration.vertexMode = D3DFOG_LINEAR;
}

// OFFSET: 0x0055A500
// FUNCTION: fn_02080
void RendererFogDX7::Apply(
  IDirect3DDevice7* device, const D3DDEVICEDESC7& caps, float aspect, const FogConfiguration& configuration, CRenderSystemBase* renderSystem
) {
  if (!this->dirty) {
    return;
  }

  if (this->enabled) {
    const float start = configuration.start * 1490.0f + 10.0f;
    const float end = configuration.end * 1490.0f + 10.0f;
    const bool vertexFog = (caps.dpcTriCaps.dwRasterCaps & D3DPRASTERCAPS_FOGVERTEX) != 0;
    D3DMATRIX identity{};
    identity._11 = identity._22 = identity._33 = identity._44 = 1;
    D3DMATRIX projection;
    PerspectiveMatrixDX7(projection, 0.26179934f, aspect, 10.0f, 1500.0f);
    device->SetTransform(D3DTRANSFORMSTATE_WORLD, &identity);
    device->SetTransform(D3DTRANSFORMSTATE_PROJECTION, &projection);
    device->SetTransform(D3DTRANSFORMSTATE_VIEW, &identity);
    device->SetRenderState(D3DRENDERSTATE_FOGCOLOR, configuration.color);

    if (configuration.vertexMode == D3DFOG_LINEAR) {
      if (vertexFog) {
        device->SetRenderState(D3DRENDERSTATE_FOGSTART, std::bit_cast<unsigned>(start));
        device->SetRenderState(D3DRENDERSTATE_FOGEND, std::bit_cast<unsigned>(end));
        device->SetRenderState(D3DRENDERSTATE_FOGDENSITY, std::bit_cast<unsigned>(configuration.density));
        device->SetRenderState(D3DRENDERSTATE_FOGTABLEMODE, D3DFOG_NONE);
        device->SetRenderState(D3DRENDERSTATE_FOGVERTEXMODE, configuration.vertexMode);
      } else {
        device->SetRenderState(D3DRENDERSTATE_FOGENABLE, 0);
      }
    } else {
      if (vertexFog) {
        device->SetRenderState(D3DRENDERSTATE_FOGTABLEMODE, D3DFOG_NONE);
        device->SetRenderState(D3DRENDERSTATE_FOGVERTEXMODE, configuration.vertexMode);
      } else {
        ShowErrorDialog(renderSystem, "Your graphic accelerator does not support fog effect.", 0);
      }

      device->SetRenderState(D3DRENDERSTATE_FOGDENSITY, std::bit_cast<unsigned>(configuration.density));
    }

    if (vertexFog && configuration.range) {
      device->SetRenderState(D3DRENDERSTATE_RANGEFOGENABLE, 1);
    }
  }

  this->dirty = 0;
}