#pragma once

#include <string>
#include <unistd.h>
#include <SDL.h>
#include <SDL_image.h>
#include <utils.hpp>
#include <hqn/hqn.h> 
#include <hqn/hqn_gui_controller.h>
#include "emuInstance.hpp"

#define _INVERSE_FRAME_RATE 16667

struct stepData_t
{
  std::string input;
  uint8_t* stateData;
  hash_t hash;
};

class PlaybackInstance
{
 public:

  void addStep(const std::string& input)
  {
    stepData_t step;
    step.input = input;
    step.stateData = (uint8_t*) malloc(_emu->getStateSize());
    _emu->serializeState(step.stateData);
    step.hash = _emu->getStateHash();

    // Adding the step into the sequence
    _stepSequence.push_back(step);
  }

  // Initializes the playback module instance
 PlaybackInstance(EmuInstance* emu, const std::vector<std::string>& sequence, const std::string& overlayPath = "") : _emu(emu)
 {
   // Loading Emulator instance HQN
  _hqnState.m_emu = _emu->getInternalEmulator();
  static uint8_t video_buffer[Nes_Emu::image_width * Nes_Emu::image_height];
  _hqnState.m_emu->set_pixels(video_buffer, Nes_Emu::image_width+8);

  // Building sequence information
  for (const auto& input : sequence)
  {
    // Adding new step
    addStep(input);

    // Advance state based on the input received
    _emu->advanceState(input);
  }

  // Adding last step with no input
  addStep("<End Of Sequence>");

  // Loading overlay, if provided
  if (overlayPath != "")
  {
    // Using overlay
    _useOverlay = true;

    // Loading overlay images
    std::string imagePath;

    imagePath = _overlayPath + std::string("/base.png");
    _overlayBaseSurface = IMG_Load(imagePath.c_str());
    if (_overlayBaseSurface == NULL) EXIT_WITH_ERROR("[Error] Could not load image: %s, Reason: %s\n", imagePath.c_str(), SDL_GetError());

    imagePath = _overlayPath + std::string("/button_a.png");
    _overlayButtonASurface = IMG_Load(imagePath.c_str());
    if (_overlayButtonASurface == NULL) EXIT_WITH_ERROR("[Error] Could not load image: %s, Reason: %s\n", imagePath.c_str(), SDL_GetError());

    imagePath = _overlayPath + std::string("/button_b.png");
    _overlayButtonBSurface = IMG_Load(imagePath.c_str());
    if (_overlayButtonBSurface == NULL) EXIT_WITH_ERROR("[Error] Could not load image: %s, Reason: %s\n", imagePath.c_str(), SDL_GetError());

    imagePath = _overlayPath + std::string("/button_select.png");
    _overlayButtonSelectSurface = IMG_Load(imagePath.c_str());
    if (_overlayButtonSelectSurface == NULL) EXIT_WITH_ERROR("[Error] Could not load image: %s, Reason: %s\n", imagePath.c_str(), SDL_GetError());

    imagePath = _overlayPath + std::string("/button_start.png");
    _overlayButtonStartSurface = IMG_Load(imagePath.c_str());
    if (_overlayButtonStartSurface == NULL) EXIT_WITH_ERROR("[Error] Could not load image: %s, Reason: %s\n", imagePath.c_str(), SDL_GetError());

    imagePath = _overlayPath + std::string("/button_left.png");
    _overlayButtonLeftSurface = IMG_Load(imagePath.c_str());
    if (_overlayButtonLeftSurface == NULL) EXIT_WITH_ERROR("[Error] Could not load image: %s, Reason: %s\n", imagePath.c_str(), SDL_GetError());

    imagePath = _overlayPath + std::string("/button_right.png");
    _overlayButtonRightSurface = IMG_Load(imagePath.c_str());
    if (_overlayButtonRightSurface == NULL) EXIT_WITH_ERROR("[Error] Could not load image: %s, Reason: %s\n", imagePath.c_str(), SDL_GetError());

    imagePath = _overlayPath + std::string("/button_up.png");
    _overlayButtonUpSurface = IMG_Load(imagePath.c_str());
    if (_overlayButtonUpSurface == NULL) EXIT_WITH_ERROR("[Error] Could not load image: %s, Reason: %s\n", imagePath.c_str(), SDL_GetError());

    imagePath = _overlayPath + std::string("/button_down.png");
    _overlayButtonDownSurface = IMG_Load(imagePath.c_str());
    if (_overlayButtonDownSurface == NULL) EXIT_WITH_ERROR("[Error] Could not load image: %s, Reason: %s\n", imagePath.c_str(), SDL_GetError());
  }

  // Opening rendering window
  SDL_SetMainReady();

  // We can only call SDL_InitSubSystem once
  if (!SDL_WasInit(SDL_INIT_VIDEO))
   if (SDL_InitSubSystem(SDL_INIT_VIDEO) != 0)
    EXIT_WITH_ERROR("Failed to initialize video: %s", SDL_GetError());

  // Creating HQN GUI
  _hqnGUI = hqn::GUIController::create(_hqnState);
  _hqnGUI->setScale(1);
 }

 // Function to render frame
 void renderFrame(const size_t stepId) 
 {
  // Checking the required step id does not exceed contents of the sequence
  if (stepId > _stepSequence.size()) EXIT_WITH_ERROR("[Error] Attempting to render a step larger than the step sequence");
 
  // Getting step information
  const auto& step = _stepSequence[stepId];

  // Pointer to overlay images (NULL if unused)
  SDL_Surface* overlayButtonASurface = NULL;
  SDL_Surface* overlayButtonBSurface = NULL;
  SDL_Surface* overlayButtonSelectSurface = NULL;
  SDL_Surface* overlayButtonStartSurface = NULL;
  SDL_Surface* overlayButtonLeftSurface = NULL;
  SDL_Surface* overlayButtonRightSurface = NULL;
  SDL_Surface* overlayButtonUpSurface = NULL;
  SDL_Surface* overlayButtonDownSurface = NULL;

  // Load correct overlay images, if using overlay
  if (_useOverlay == true)
  {
    if (step.input.find("A") != std::string::npos) overlayButtonASurface = _overlayButtonASurface;
    if (step.input.find("B") != std::string::npos) overlayButtonBSurface = _overlayButtonBSurface;
    if (step.input.find("S") != std::string::npos) overlayButtonSelectSurface = _overlayButtonSelectSurface;
    if (step.input.find("T") != std::string::npos) overlayButtonStartSurface = _overlayButtonStartSurface;
    if (step.input.find("L") != std::string::npos) overlayButtonLeftSurface = _overlayButtonLeftSurface;
    if (step.input.find("R") != std::string::npos) overlayButtonRightSurface = _overlayButtonRightSurface;
    if (step.input.find("U") != std::string::npos) overlayButtonUpSurface = _overlayButtonUpSurface;
    if (step.input.find("D") != std::string::npos) overlayButtonDownSurface = _overlayButtonDownSurface;
  }

  // Since we do not store the blit information (too much memory), we need to load the previous frame and re-run the input

  // If its the first step, then simply reset
  if (stepId == 0) _emu->getInternalEmulator()->reset();

  // Else we load the previous frame
  if (stepId > 0)
  {
    const auto stateData = getStateData(stepId-1);
    _emu->deserializeState(stateData);
    _emu->advanceState(getStateInput(stepId-1));
  }
  
  // Updating image
   int32_t curBlit[BLIT_SIZE];
   saveBlit(_emu->getInternalEmulator(), curBlit, hqn::HQNState::NES_VIDEO_PALETTE, 0, 0, 0, 0);
  _hqnGUI->update_blit(curBlit, _overlayBaseSurface, overlayButtonASurface, overlayButtonBSurface, overlayButtonSelectSurface, overlayButtonStartSurface, overlayButtonLeftSurface, overlayButtonRightSurface, overlayButtonUpSurface, overlayButtonDownSurface);
 }

 size_t getSequenceLength() const
 {
  return _stepSequence.size();
 }

 const std::string getInput(const size_t stepId) const
 {
  // Checking the required step id does not exceed contents of the sequence
  if (stepId > _stepSequence.size()) EXIT_WITH_ERROR("[Error] Attempting to render a step larger than the step sequence");
 
  // Getting step information
  const auto& step = _stepSequence[stepId];

  // Returning step input
  return step.input;
 }

 const uint8_t* getStateData(const size_t stepId) const
 {
  // Checking the required step id does not exceed contents of the sequence
  if (stepId > _stepSequence.size()) EXIT_WITH_ERROR("[Error] Attempting to render a step larger than the step sequence");
 
  // Getting step information
  const auto& step = _stepSequence[stepId];

  // Returning step input
  return step.stateData;
 }

 const hash_t getStateHash(const size_t stepId) const
 {
  // Checking the required step id does not exceed contents of the sequence
  if (stepId > _stepSequence.size()) EXIT_WITH_ERROR("[Error] Attempting to render a step larger than the step sequence");
 
  // Getting step information
  const auto& step = _stepSequence[stepId];

  // Returning step input
  return step.hash;
 }

const std::string getStateInput(const size_t stepId) const
 {
  // Checking the required step id does not exceed contents of the sequence
  if (stepId > _stepSequence.size()) EXIT_WITH_ERROR("[Error] Attempting to render a step larger than the step sequence");
 
  // Getting step information
  const auto& step = _stepSequence[stepId];

  // Returning step input
  return step.input;
 }


 private:

 // Internal sequence information
 std::vector<stepData_t> _stepSequence;

 // Storage for the HQN state
 hqn::HQNState _hqnState;

 // Storage for the HQN GUI controller
 hqn::GUIController* _hqnGUI;

 // Pointer to the contained emulator instance
 EmuInstance* const _emu;

 // Flag to store whether to use the button overlay
 bool _useOverlay = false;

 // Overlay info
 std::string _overlayPath;
 SDL_Surface* _overlayBaseSurface = NULL;
 SDL_Surface* _overlayButtonASurface;
 SDL_Surface* _overlayButtonBSurface;
 SDL_Surface* _overlayButtonSelectSurface;
 SDL_Surface* _overlayButtonStartSurface;
 SDL_Surface* _overlayButtonLeftSurface;
 SDL_Surface* _overlayButtonRightSurface;
 SDL_Surface* _overlayButtonUpSurface;
 SDL_Surface* _overlayButtonDownSurface;
};