// Copyright 2008 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

// DL facts:
//  Ikaruga uses (nearly) NO display lists!
//  Zelda WW uses TONS of display lists
//  Zelda TP uses almost 100% display lists except menus (we like this!)
//  Super Mario Galaxy has nearly all geometry and more than half of the state in DLs (great!)

// Note that it IS NOT GENERALLY POSSIBLE to precompile display lists! You can compile them as they
// are while interpreting them, and hope that the vertex format doesn't change, though, if you do
// it right when they are called. The reason is that the vertex format affects the sizes of the
// vertices.

#include "VideoCommon/OpcodeDecoding.h"

#include "Common/Assert.h"
#include "Common/Logging/Log.h"
#include "Core/FifoPlayer/FifoRecorder.h"
#include "Core/HW/Memmap.h"
#include "VideoCommon/BPMemory.h"
#include "VideoCommon/CPMemory.h"
#include "VideoCommon/CommandProcessor.h"
#include "VideoCommon/DataReader.h"
#include "VideoCommon/Fifo.h"
#include "VideoCommon/Statistics.h"
#include "VideoCommon/VertexLoaderBase.h"
#include "VideoCommon/VertexLoaderManager.h"
#include "VideoCommon/VertexShaderManager.h"
#include "VideoCommon/XFMemory.h"
#include "VideoCommon/XFStructs.h"

namespace OpcodeDecoder
{
bool s_is_fifo_error_seen = false;
bool g_record_fifo_data = false;

void Init()
{
  s_is_fifo_error_seen = false;
}

template <bool is_preprocess>
class RunCallback final : public Callback
{
public:
  OPCODE_CALLBACK(void OnXF(u16 address, u8 count, const u8* data))
  {
    m_cycles += 18 + 6 * count;

    if constexpr (!is_preprocess)
    {
      LoadXFReg(address, count, data);

      INCSTAT(g_stats.this_frame.num_xf_loads);
    }
  }
  OPCODE_CALLBACK(void OnCP(u8 command, u32 value))
  {
    m_cycles += 12;
    if constexpr (!is_preprocess)
    {
      // TODO: Move all dirty state checking here or to VertexLoaderManager,
      // instead of it being in CPState
      if (command == MATINDEX_A)
        VertexShaderManager::SetTexMatrixChangedA(value);
      else if (command == MATINDEX_B)
        VertexShaderManager::SetTexMatrixChangedB(value);

      INCSTAT(g_stats.this_frame.num_cp_loads);
    }
    GetCPState().LoadCPReg(command, value);
  }
  OPCODE_CALLBACK(void OnBP(u8 command, u32 value))
  {
    m_cycles += 12;

    if constexpr (is_preprocess)
    {
      LoadBPRegPreprocess(command, value, m_cycles);
    }
    else
    {
      LoadBPReg(command, value, m_cycles);
      INCSTAT(g_stats.this_frame.num_bp_loads);
    }
  }
  OPCODE_CALLBACK(void OnIndexedLoad(CPArray array, u32 index, u16 address, u8 size))
  {
    m_cycles += 6;

    if constexpr (is_preprocess)
      PreprocessIndexedXF(array, index, address, size);
    else
      LoadIndexedXF(array, index, address, size);
  }
  OPCODE_CALLBACK(void OnPrimitiveCommand(OpcodeDecoder::Primitive primitive, u8 vat,
                                          u32 vertex_size, u16 num_vertices, const u8* vertex_data))
  {
    // load vertices
    const u32 size = vertex_size * num_vertices;

    // HACK
    DataReader src{const_cast<u8*>(vertex_data), const_cast<u8*>(vertex_data) + size};
    const u32 bytes =
        VertexLoaderManager::RunVertices(vat, primitive, num_vertices, src, is_preprocess);

    ASSERT(bytes == size);

    // 4 GPU ticks per vertex, 3 CPU ticks per GPU tick
    m_cycles += num_vertices * 4 * 3 + 6;
  }
  // This can't be inlined since it calls Run, which makes it recursive
  // m_in_display_list prevents it from actually recursing infinitely, but there's no real benefit
  // to inlining Run for the display list directly.
  OPCODE_CALLBACK_NOINLINE(void OnDisplayList(u32 address, u32 size))
  {
    m_cycles += 6;

    if (m_in_display_list)
    {
      WARN_LOG_FMT(VIDEO, "recursive display list detected");
    }
    else
    {
      m_in_display_list = true;

      if constexpr (is_preprocess)
      {
        const u8* const start_address = Memory::GetPointer(address);

        Fifo::PushFifoAuxBuffer(start_address, size);

        if (start_address != nullptr)
        {
          Run(start_address, size, *this);
        }
      }
      else
      {
        const u8* start_address;

        if (Fifo::UseDeterministicGPUThread())
          start_address = static_cast<u8*>(Fifo::PopFifoAuxBuffer(size));
        else
          start_address = Memory::GetPointer(address);

        // Avoid the crash if Memory::GetPointer failed ..
        if (start_address != nullptr)
        {
          // temporarily swap dl and non-dl (small "hack" for the stats)
          g_stats.SwapDL();

          Run(start_address, size, *this);
          INCSTAT(g_stats.this_frame.num_dlists_called);

          // un-swap
          g_stats.SwapDL();
        }
      }

      m_in_display_list = false;
    }
  }
  OPCODE_CALLBACK(void OnNop(u32 count))
  {
    m_cycles += 6 * count;  // Hm, this means that we scan over nop streams pretty slowly...
  }
  OPCODE_CALLBACK(void OnUnknown(u8 opcode, const u8* data))
  {
    if (static_cast<Opcode>(opcode) == Opcode::GX_UNKNOWN_RESET)
    {
      // Datel software uses this command
      m_cycles += 6;
      DEBUG_LOG_FMT(VIDEO, "GX Reset?");
    }
    else if (static_cast<Opcode>(opcode) == Opcode::GX_CMD_UNKNOWN_METRICS)
    {
      // 'Zelda Four Swords' calls it and checks the metrics registers after that
      m_cycles += 6;
      DEBUG_LOG_FMT(VIDEO, "GX 0x44");
    }
    else if (static_cast<Opcode>(opcode) == Opcode::GX_CMD_INVL_VC)
    {
      // Invalidate Vertex Cache
      m_cycles += 6;
      DEBUG_LOG_FMT(VIDEO, "Invalidate (vertex cache?)");
    }
    else
    {
      if (!s_is_fifo_error_seen)
        CommandProcessor::HandleUnknownOpcode(opcode, data, is_preprocess);
      ERROR_LOG_FMT(VIDEO, "FIFO: Unknown Opcode({:#04x} @ {}, preprocessing = {})", opcode,
                    fmt::ptr(data), is_preprocess ? "yes" : "no");
      s_is_fifo_error_seen = true;
      m_cycles += 1;
    }
  }

  OPCODE_CALLBACK(void OnCommand(const u8* data, u32 size))
  {
    ASSERT(size >= 1);
    if constexpr (!is_preprocess)
    {
      // Display lists get added directly into the FIFO stream since this same callback is used to
      // process them.
      if (g_record_fifo_data && static_cast<Opcode>(data[0]) != Opcode::GX_CMD_CALL_DL)
      {
        FifoRecorder::GetInstance().WriteGPCommand(data, size);
      }
    }
  }

  OPCODE_CALLBACK(CPState& GetCPState())
  {
    if constexpr (is_preprocess)
      return g_preprocess_cp_state;
    else
      return g_main_cp_state;
  }

  u32 m_cycles = 0;
  bool m_in_display_list = false;
};

template <bool is_preprocess>
u8* RunFifo(DataReader src, u32* cycles)
{
  using CallbackT = RunCallback<is_preprocess>;
  auto callback = CallbackT{};
  u32 size = Run(src.GetPointer(), static_cast<u32>(src.size()), callback);

  if (cycles != nullptr)
    *cycles = callback.m_cycles;

  src.Skip(size);
  return src.GetPointer();
}

template u8* RunFifo<true>(DataReader src, u32* cycles);
template u8* RunFifo<false>(DataReader src, u32* cycles);

}  // namespace OpcodeDecoder