// Copyright 2014 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#pragma once

#include <cstddef>
#include <stack>
#include <unordered_map>

#include "Common/BitField.h"
#include "Common/CommonTypes.h"
#include "VideoBackends/D3D/D3DBase.h"
#include "VideoCommon/BPMemory.h"

struct ID3D11BlendState;
struct ID3D11DepthStencilState;
struct ID3D11RasterizerState;

namespace DX11
{
union RasterizerState
{
  BitField<0, 2, D3D11_CULL_MODE> cull_mode;

  u32 packed;
};

union BlendState
{
  BitField<0, 1, u32> blend_enable;
  BitField<1, 3, D3D11_BLEND_OP> blend_op;
  BitField<4, 4, u32> write_mask;
  BitField<8, 5, D3D11_BLEND> src_blend;
  BitField<13, 5, D3D11_BLEND> dst_blend;
  BitField<18, 1, u32> use_dst_alpha;

  u32 packed;
};

union SamplerState
{
  BitField<0, 3, u64> min_filter;
  BitField<3, 1, u64> mag_filter;
  BitField<4, 8, u64> min_lod;
  BitField<12, 8, u64> max_lod;
  BitField<20, 8, s64> lod_bias;
  BitField<28, 2, u64> wrap_s;
  BitField<30, 2, u64> wrap_t;
  BitField<32, 5, u64> max_anisotropy;

  u64 packed;
};

class StateCache
{
public:
  // Get existing or create new render state.
  // Returned objects is owned by the cache and does not need to be released.
  ID3D11SamplerState* Get(SamplerState state);
  ID3D11BlendState* Get(BlendState state);
  ID3D11RasterizerState* Get(RasterizerState state);
  ID3D11DepthStencilState* Get(ZMode state);

  // Release all cached states and clear hash tables.
  void Clear();

private:
  std::unordered_map<u32, ID3D11DepthStencilState*> m_depth;
  std::unordered_map<u32, ID3D11RasterizerState*> m_raster;
  std::unordered_map<u32, ID3D11BlendState*> m_blend;
  std::unordered_map<u64, ID3D11SamplerState*> m_sampler;
};

namespace D3D
{
template <typename T>
class AutoState
{
public:
  AutoState(const T* object);
  AutoState(const AutoState<T>& source);
  ~AutoState();

  const inline T* GetPtr() const { return state; }
private:
  const T* state;
};

typedef AutoState<ID3D11BlendState> AutoBlendState;
typedef AutoState<ID3D11DepthStencilState> AutoDepthStencilState;
typedef AutoState<ID3D11RasterizerState> AutoRasterizerState;

class StateManager
{
public:
  StateManager();

  // call any of these to change the affected states
  void PushBlendState(const ID3D11BlendState* state);
  void PushDepthState(const ID3D11DepthStencilState* state);
  void PushRasterizerState(const ID3D11RasterizerState* state);

  // call these after drawing
  void PopBlendState();
  void PopDepthState();
  void PopRasterizerState();

  void SetTexture(size_t index, ID3D11ShaderResourceView* texture)
  {
    if (m_current.textures[index] != texture)
      m_dirtyFlags |= DirtyFlag_Texture0 << index;

    m_pending.textures[index] = texture;
  }

  void SetSampler(size_t index, ID3D11SamplerState* sampler)
  {
    if (m_current.samplers[index] != sampler)
      m_dirtyFlags |= DirtyFlag_Sampler0 << index;

    m_pending.samplers[index] = sampler;
  }

  void SetPixelConstants(ID3D11Buffer* buffer0, ID3D11Buffer* buffer1 = nullptr)
  {
    if (m_current.pixelConstants[0] != buffer0 || m_current.pixelConstants[1] != buffer1)
      m_dirtyFlags |= DirtyFlag_PixelConstants;

    m_pending.pixelConstants[0] = buffer0;
    m_pending.pixelConstants[1] = buffer1;
  }

  void SetVertexConstants(ID3D11Buffer* buffer)
  {
    if (m_current.vertexConstants != buffer)
      m_dirtyFlags |= DirtyFlag_VertexConstants;

    m_pending.vertexConstants = buffer;
  }

  void SetGeometryConstants(ID3D11Buffer* buffer)
  {
    if (m_current.geometryConstants != buffer)
      m_dirtyFlags |= DirtyFlag_GeometryConstants;

    m_pending.geometryConstants = buffer;
  }

  void SetVertexBuffer(ID3D11Buffer* buffer, u32 stride, u32 offset)
  {
    if (m_current.vertexBuffer != buffer || m_current.vertexBufferStride != stride ||
        m_current.vertexBufferOffset != offset)
      m_dirtyFlags |= DirtyFlag_VertexBuffer;

    m_pending.vertexBuffer = buffer;
    m_pending.vertexBufferStride = stride;
    m_pending.vertexBufferOffset = offset;
  }

  void SetIndexBuffer(ID3D11Buffer* buffer)
  {
    if (m_current.indexBuffer != buffer)
      m_dirtyFlags |= DirtyFlag_IndexBuffer;

    m_pending.indexBuffer = buffer;
  }

  void SetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY topology)
  {
    if (m_current.topology != topology)
      m_dirtyFlags |= DirtyFlag_InputAssembler;

    m_pending.topology = topology;
  }

  void SetInputLayout(ID3D11InputLayout* layout)
  {
    if (m_current.inputLayout != layout)
      m_dirtyFlags |= DirtyFlag_InputAssembler;

    m_pending.inputLayout = layout;
  }

  void SetPixelShader(ID3D11PixelShader* shader)
  {
    if (m_current.pixelShader != shader)
      m_dirtyFlags |= DirtyFlag_PixelShader;

    m_pending.pixelShader = shader;
  }

  void SetPixelShaderDynamic(ID3D11PixelShader* shader, ID3D11ClassInstance* const* classInstances,
                             u32 classInstancesCount)
  {
    D3D::context->PSSetShader(shader, classInstances, classInstancesCount);
    m_current.pixelShader = shader;
    m_pending.pixelShader = shader;
  }

  void SetVertexShader(ID3D11VertexShader* shader)
  {
    if (m_current.vertexShader != shader)
      m_dirtyFlags |= DirtyFlag_VertexShader;

    m_pending.vertexShader = shader;
  }

  void SetGeometryShader(ID3D11GeometryShader* shader)
  {
    if (m_current.geometryShader != shader)
      m_dirtyFlags |= DirtyFlag_GeometryShader;

    m_pending.geometryShader = shader;
  }

  // removes currently set texture from all slots, returns mask of previously bound slots
  u32 UnsetTexture(ID3D11ShaderResourceView* srv);
  void SetTextureByMask(u32 textureSlotMask, ID3D11ShaderResourceView* srv);

  // call this immediately before any drawing operation or to explicitly apply pending resource
  // state changes
  void Apply();

private:
  std::stack<AutoBlendState> m_blendStates;
  std::stack<AutoDepthStencilState> m_depthStates;
  std::stack<AutoRasterizerState> m_rasterizerStates;

  ID3D11BlendState* m_currentBlendState;
  ID3D11DepthStencilState* m_currentDepthState;
  ID3D11RasterizerState* m_currentRasterizerState;

  enum DirtyFlags
  {
    DirtyFlag_Texture0 = 1 << 0,
    DirtyFlag_Texture1 = 1 << 1,
    DirtyFlag_Texture2 = 1 << 2,
    DirtyFlag_Texture3 = 1 << 3,
    DirtyFlag_Texture4 = 1 << 4,
    DirtyFlag_Texture5 = 1 << 5,
    DirtyFlag_Texture6 = 1 << 6,
    DirtyFlag_Texture7 = 1 << 7,

    DirtyFlag_Sampler0 = 1 << 8,
    DirtyFlag_Sampler1 = 1 << 9,
    DirtyFlag_Sampler2 = 1 << 10,
    DirtyFlag_Sampler3 = 1 << 11,
    DirtyFlag_Sampler4 = 1 << 12,
    DirtyFlag_Sampler5 = 1 << 13,
    DirtyFlag_Sampler6 = 1 << 14,
    DirtyFlag_Sampler7 = 1 << 15,

    DirtyFlag_PixelConstants = 1 << 16,
    DirtyFlag_VertexConstants = 1 << 17,
    DirtyFlag_GeometryConstants = 1 << 18,

    DirtyFlag_VertexBuffer = 1 << 19,
    DirtyFlag_IndexBuffer = 1 << 20,

    DirtyFlag_PixelShader = 1 << 21,
    DirtyFlag_VertexShader = 1 << 22,
    DirtyFlag_GeometryShader = 1 << 23,

    DirtyFlag_InputAssembler = 1 << 24,
  };

  u32 m_dirtyFlags;

  struct Resources
  {
    ID3D11ShaderResourceView* textures[8];
    ID3D11SamplerState* samplers[8];
    ID3D11Buffer* pixelConstants[2];
    ID3D11Buffer* vertexConstants;
    ID3D11Buffer* geometryConstants;
    ID3D11Buffer* vertexBuffer;
    ID3D11Buffer* indexBuffer;
    u32 vertexBufferStride;
    u32 vertexBufferOffset;
    D3D11_PRIMITIVE_TOPOLOGY topology;
    ID3D11InputLayout* inputLayout;
    ID3D11PixelShader* pixelShader;
    ID3D11VertexShader* vertexShader;
    ID3D11GeometryShader* geometryShader;
  };

  Resources m_pending;
  Resources m_current;
};

extern StateManager* stateman;

}  // namespace

}  // namespace DX11