#pragma once
#include "common/heap_array.h"
#include "gpu.h"
#include "host_display.h"
#include <sstream>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

class GPU_HW : public GPU
{
public:
  enum class BatchRenderMode : u8
  {
    TransparencyDisabled,
    TransparentAndOpaque,
    OnlyOpaque,
    OnlyTransparent
  };

  enum class InterlacedRenderMode : u8
  {
    None,
    InterleavedFields,
    SeparateFields
  };

  GPU_HW();
  virtual ~GPU_HW();

  virtual bool IsHardwareRenderer() const override;

  virtual bool Initialize(HostDisplay* host_display) override;
  virtual void Reset() override;
  virtual bool DoState(StateWrapper& sw) override;
  virtual void UpdateSettings() override;
  virtual void UpdateResolutionScale() override;

protected:
  enum : u32
  {
    VRAM_UPDATE_TEXTURE_BUFFER_SIZE = VRAM_WIDTH * VRAM_HEIGHT * sizeof(u32),
    VERTEX_BUFFER_SIZE = 1 * 1024 * 1024,
    UNIFORM_BUFFER_SIZE = 512 * 1024,
    MAX_BATCH_VERTEX_COUNTER_IDS = 65536 - 2,
    MAX_VERTICES_FOR_RECTANGLE = 6 * (((MAX_PRIMITIVE_WIDTH + (TEXTURE_PAGE_WIDTH - 1)) / TEXTURE_PAGE_WIDTH) + 1u) *
                                 (((MAX_PRIMITIVE_HEIGHT + (TEXTURE_PAGE_HEIGHT - 1)) / TEXTURE_PAGE_HEIGHT) + 1u)
  };

  struct BatchVertex
  {
    float x;
    float y;
    float z;
    float w;
    u32 color;
    u32 texpage;
    u16 u; // 16-bit texcoords are needed for 256 extent rectangles
    u16 v;

    ALWAYS_INLINE void Set(float x_, float y_, float z_, float w_, u32 color_, u32 texpage_, u16 packed_texcoord)
    {
      Set(x_, y_, z_, w_, color_, texpage_, packed_texcoord & 0xFF, (packed_texcoord >> 8));
    }

    ALWAYS_INLINE void Set(float x_, float y_, float z_, float w_, u32 color_, u32 texpage_, u16 u_, u16 v_)
    {
      x = x_;
      y = y_;
      z = z_;
      w = w_;
      color = color_;
      texpage = texpage_;
      u = u_;
      v = v_;
    }
  };

  struct BatchConfig
  {
    TextureMode texture_mode;
    TransparencyMode transparency_mode;
    bool dithering;
    bool interlacing;
    bool set_mask_while_drawing;
    bool check_mask_before_draw;

    // We need two-pass rendering when using BG-FG blending and texturing, as the transparency can be enabled
    // on a per-pixel basis, and the opaque pixels shouldn't be blended at all.
    bool NeedsTwoPassRendering() const
    {
      return transparency_mode == GPU::TransparencyMode::BackgroundMinusForeground &&
             texture_mode != TextureMode::Disabled;
    }

    // Returns the render mode for this batch.
    BatchRenderMode GetRenderMode() const
    {
      return transparency_mode == TransparencyMode::Disabled ? BatchRenderMode::TransparencyDisabled :
                                                               BatchRenderMode::TransparentAndOpaque;
    }
  };

  struct BatchUBOData
  {
    u32 u_texture_window_mask[2];
    u32 u_texture_window_offset[2];
    float u_src_alpha_factor;
    float u_dst_alpha_factor;
    u32 u_interlaced_displayed_field;
    u32 u_set_mask_while_drawing;
  };

  struct VRAMFillUBOData
  {
    float u_fill_color[4];
    u32 u_interlaced_displayed_field;
  };

  struct VRAMWriteUBOData
  {
    u32 u_dst_x;
    u32 u_dst_y;
    u32 u_end_x;
    u32 u_end_y;
    u32 u_width;
    u32 u_height;
    u32 u_buffer_base_offset;
    u32 u_mask_or_bits;
    float u_depth_value;
  };

  struct VRAMCopyUBOData
  {
    u32 u_src_x;
    u32 u_src_y;
    u32 u_dst_x;
    u32 u_dst_y;
    u32 u_end_x;
    u32 u_end_y;
    u32 u_width;
    u32 u_height;
    u32 u_set_mask_bit;
    float u_depth_value;
  };

  struct RendererStats
  {
    u32 num_batches;
    u32 num_vram_read_texture_updates;
    u32 num_uniform_buffer_updates;
  };

  static constexpr std::tuple<float, float, float, float> RGBA8ToFloat(u32 rgba)
  {
    return std::make_tuple(static_cast<float>(rgba & UINT32_C(0xFF)) * (1.0f / 255.0f),
                           static_cast<float>((rgba >> 8) & UINT32_C(0xFF)) * (1.0f / 255.0f),
                           static_cast<float>((rgba >> 16) & UINT32_C(0xFF)) * (1.0f / 255.0f),
                           static_cast<float>(rgba >> 24) * (1.0f / 255.0f));
  }

  virtual void UpdateVRAMReadTexture();
  virtual void UpdateDepthBufferFromMaskBit() = 0;
  virtual void SetScissorFromDrawingArea() = 0;
  virtual void MapBatchVertexPointer(u32 required_vertices) = 0;
  virtual void UnmapBatchVertexPointer(u32 used_vertices) = 0;
  virtual void UploadUniformBuffer(const void* uniforms, u32 uniforms_size) = 0;
  virtual void DrawBatchVertices(BatchRenderMode render_mode, u32 base_vertex, u32 num_vertices) = 0;

  u32 CalculateResolutionScale() const;

  void SetFullVRAMDirtyRectangle()
  {
    m_vram_dirty_rect.Set(0, 0, VRAM_WIDTH, VRAM_HEIGHT);
    m_draw_mode.SetTexturePageChanged();
  }
  void ClearVRAMDirtyRectangle() { m_vram_dirty_rect.SetInvalid(); }
  void IncludeVRAMDityRectangle(const Common::Rectangle<u32>& rect);

  bool IsFlushed() const { return m_batch_current_vertex_ptr == m_batch_start_vertex_ptr; }

  u32 GetBatchVertexSpace() const { return static_cast<u32>(m_batch_end_vertex_ptr - m_batch_current_vertex_ptr); }
  u32 GetBatchVertexCount() const { return static_cast<u32>(m_batch_current_vertex_ptr - m_batch_start_vertex_ptr); }
  void EnsureVertexBufferSpace(u32 required_vertices);
  void EnsureVertexBufferSpaceForCurrentCommand();
  void ResetBatchVertexDepth();

  /// Returns the value to be written to the depth buffer for the current operation for mask bit emulation.
  ALWAYS_INLINE float GetCurrentNormalizedVertexDepth() const
  {
    return 1.0f - (static_cast<float>(m_current_depth) / 65535.0f);
  }

  /// Returns the interlaced mode to use when scanning out/displaying.
  ALWAYS_INLINE InterlacedRenderMode GetInterlacedRenderMode() const
  {
    if (IsInterlacedDisplayEnabled())
    {
      return m_GPUSTAT.vertical_resolution ? InterlacedRenderMode::InterleavedFields :
                                             InterlacedRenderMode::SeparateFields;
    }
    else
    {
      return InterlacedRenderMode::None;
    }
  }

  void FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color) override;
  void UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data) override;
  void CopyVRAM(u32 src_x, u32 src_y, u32 dst_x, u32 dst_y, u32 width, u32 height) override;
  void DispatchRenderCommand() override;
  void FlushRender() override;
  void DrawRendererStats(bool is_idle_frame) override;

  void CalcScissorRect(int* left, int* top, int* right, int* bottom);

  std::tuple<s32, s32> ScaleVRAMCoordinates(s32 x, s32 y) const
  {
    return std::make_tuple(x * s32(m_resolution_scale), y * s32(m_resolution_scale));
  }

  /// Computes the area affected by a VRAM transfer, including wrap-around of X.
  Common::Rectangle<u32> GetVRAMTransferBounds(u32 x, u32 y, u32 width, u32 height) const;

  /// Returns true if the VRAM copy shader should be used (oversized copies, masking).
  bool UseVRAMCopyShader(u32 src_x, u32 src_y, u32 dst_x, u32 dst_y, u32 width, u32 height) const;

  VRAMFillUBOData GetVRAMFillUBOData(u32 x, u32 y, u32 width, u32 height, u32 color) const;
  VRAMWriteUBOData GetVRAMWriteUBOData(u32 x, u32 y, u32 width, u32 height, u32 buffer_offset) const;
  VRAMCopyUBOData GetVRAMCopyUBOData(u32 src_x, u32 src_y, u32 dst_x, u32 dst_y, u32 width, u32 height) const;

  /// Expands a line into two triangles.
  void DrawLine(float x0, float y0, u32 col0, float x1, float y1, u32 col1, float depth);

  /// Handles quads with flipped texture coordinate directions.
  static void HandleFlippedQuadTextureCoordinates(BatchVertex* vertices);

  HeapArray<u16, VRAM_WIDTH * VRAM_HEIGHT> m_vram_shadow;

  BatchVertex* m_batch_start_vertex_ptr = nullptr;
  BatchVertex* m_batch_end_vertex_ptr = nullptr;
  BatchVertex* m_batch_current_vertex_ptr = nullptr;
  u32 m_batch_base_vertex = 0;
  s32 m_current_depth = 0;

  u32 m_resolution_scale = 1;
  u32 m_max_resolution_scale = 1;
  HostDisplay::RenderAPI m_render_api = HostDisplay::RenderAPI::None;
  bool m_true_color = true;
  bool m_scaled_dithering = false;
  bool m_texture_filtering = false;
  bool m_supports_dual_source_blend = false;

  BatchConfig m_batch = {};
  BatchUBOData m_batch_ubo_data = {};

  // Bounding box of VRAM area that the GPU has drawn into.
  Common::Rectangle<u32> m_vram_dirty_rect;

  // Statistics
  RendererStats m_renderer_stats = {};
  RendererStats m_last_renderer_stats = {};

  // Changed state
  bool m_batch_ubo_dirty = true;

private:
  enum : u32
  {
    MIN_BATCH_VERTEX_COUNT = 6,
    MAX_BATCH_VERTEX_COUNT = VERTEX_BUFFER_SIZE / sizeof(BatchVertex)
  };

  void LoadVertices();

  ALWAYS_INLINE void AddVertex(const BatchVertex& v)
  {
    std::memcpy(m_batch_current_vertex_ptr, &v, sizeof(BatchVertex));
    m_batch_current_vertex_ptr++;
  }

  template<typename... Args>
  ALWAYS_INLINE void AddNewVertex(Args&&... args)
  {
    m_batch_current_vertex_ptr->Set(std::forward<Args>(args)...);
    m_batch_current_vertex_ptr++;
  }

  void PrintSettingsToLog();
};