#include <fstream>
#include <iostream>
#include <filesystem>
#include <unistd.h>
#include <nlohmann/json.hpp>

#include "../includes/render.hpp"
#include "../includes/rules.hpp"
#include "../includes/world.hpp"
#include "../includes/types.hpp"
#include "imgui.h"
#include "raylib.h"
#include "rlImGui.h"


Vector2 snapToGrid(Vector2 screen, int cell_size) {
  return {static_cast<float>(round(screen.x / cell_size) * cell_size),
          static_cast<float>(round(screen.y / cell_size) * cell_size)};
}

Vector2i screenToGrid(Vector2 screen, int cell_size) {
  return {static_cast<int>(round(screen.x / cell_size)),
          static_cast<int>(round(screen.y / cell_size))};
}

int main(int ac, char **av) {
  // Load or default config
  const std::string config_file_name = "config.json";
  nlohmann::json config_json;
  MenuState menu_state = MenuState::NONE;

  std::fstream config_file(config_file_name, std::ios::in | std::ios::out);

  if (!config_file.is_open()) {
    config_file.open(config_file_name, std::ios::out);
    if (!config_file) {
      std::cerr << "Failed to create config file, the settings will not be "
                   "kepts after restart."
                << std::endl;
      return 1;
    }
    config_file.close();
    config_file.open(config_file_name, std::ios::in | std::ios::out);
    config_file << "{}";
    config_file.flush();
  }
  // Try reading the configuration
  try {
    config_file.seekg(0);
    config_file >> config_json;
  } catch (const nlohmann::json::parse_error &e) {
    std::cerr << "An error occured while loading config : " << e.what()
              << std::endl;
    std::cerr << "Please fix the configuration or remove the config.json file."
              << std::endl;
    return 1;
  }
  config_file.close();

  // Check config values or populate them
  if (!config_json.contains("cell_size") ||
      (config_json["cell_size"] < 4 || config_json["cell_size"] > 100)) {
    config_json["cell_size"] = 10;
  }
  if (!config_json.contains("screen_width") ||
      (config_json["screen_width"] < 800 ||
       config_json["screen_width"] > 1920)) {
    config_json["screen_width"] = 800;
  }
  if (!config_json.contains("screen_height") ||
      (config_json["screen_height"] < 600 ||
       config_json["screen_height"] > 1200)) {
    config_json["screen_height"] = 600;
  }
  if (!config_json.contains("dark_theme")) {
    config_json["dark_theme"] = true;
  }
  if (!config_json.contains("fps") ||
      (config_json["fps"] < 0 || config_json["fps"] > 30)) {
    config_json["fps"] = 800;
  }

  InitWindow(config_json["screen_width"], config_json["screen_height"],
             &av[0][2]);

  SetTargetFPS(60);

  rlImGuiSetup(config_json["dark_theme"]);
  // Selection window

  RenderTexture2D selectionTexture = LoadRenderTexture(200, 200);

  // Initialize objects
  World world(config_json["screen_width"].get<int>() /
                  config_json["cell_size"].get<int>(),
              config_json["screen_height"].get<int>() /
                  config_json["cell_size"].get<int>());
  Rules rules = Rules();
  Render render(config_json["cell_size"]);

  // Imgui control menu
  int fps_ctrl = config_json["fps"].get<int>();
  int cell_size_ctrl = config_json["cell_size"].get<int>();
  bool play_ctrl = true;
  bool step_ctrl = false;
  bool step_back_ctrl = false;
  bool rand_ctrl = false;
  bool edit_ctrl = false;
  bool clear_ctrl = false;
  bool settings_window = false;
  int width_ctrl = config_json["screen_width"].get<int>();
  int height_ctrl = config_json["screen_height"].get<int>();
  bool dark_theme_ctrl = config_json["dark_theme"].get<bool>();
  bool apply_ctrl = false;

  // Speed handling values
  float sim_speed = 1.0f;
  float deltaTimeAccumulator = 0.0f;
  float timePerUpdate = 1.0f / 10.0f;

  // Selection window
  Vector2 sel_pos = {0., 0.};
  bool selecting = false;
  std::vector<uint32_t> sel_data = {};
  bool sel_ctrl = false;
  char patern_name[255];
  patern_name[0] = '\0';
  std::string sel_txt_input_hint("patern name");

  // Setups
  rules.setup(&world);
  // Diplay generations
  while (!WindowShouldClose()) {
    if (menu_state == MenuState::PLAY || menu_state == MenuState::EDIT) {
      if (!play_ctrl && !edit_ctrl) {
        menu_state = MenuState::NONE;
      }
    }
    // Frames shinenigans
    float deltaTime = GetFrameTime();
    sim_speed = fps_ctrl / 10.0f;
    timePerUpdate = (1.0f / 10.0f) / sim_speed;

    auto gesture = GetGestureDetected();
    auto mousePos = GetMousePosition();
    if (rand_ctrl) {
      world.randomize();
      rand_ctrl = false;
    }
    if (clear_ctrl) {
      world.clear();
      clear_ctrl = false;
    }
    if (edit_ctrl && play_ctrl) {
      if (menu_state == MenuState::PLAY) {
        menu_state = MenuState::EDIT;
        play_ctrl = false;
      } else if (menu_state == MenuState::EDIT) {
        menu_state = MenuState::PLAY;
        edit_ctrl = false;
      }
    } else if (play_ctrl) {
      menu_state = MenuState::PLAY;
    } else if (edit_ctrl) {
      menu_state = MenuState::EDIT;
    }
    if (edit_ctrl && IsMouseButtonPressed(0) &&
        !ImGui::IsWindowHovered(ImGuiHoveredFlags_AnyWindow)) {
      menu_state = MenuState::EDIT;
      world.setCell(mousePos.x / config_json["cell_size"].get<int>(),
                    mousePos.y / config_json["cell_size"].get<int>());
    }
    // Selection behaviour
    if (!edit_ctrl && !play_ctrl) {
      if (gesture == GESTURE_TAP && !ImGui::IsWindowHovered(ImGuiHoveredFlags_AnyWindow)) {
        sel_pos = snapToGrid(mousePos, cell_size_ctrl);
        selecting = true;
      }
      if (ImGui::IsMouseReleased(0) && selecting == true && mousePos.x >=0 && mousePos.x < width_ctrl && mousePos.y >=0 && mousePos.y < height_ctrl ) {
        selecting = false;
        Vector2i p1 = screenToGrid(sel_pos, cell_size_ctrl);
        Vector2i p2 = screenToGrid(mousePos, cell_size_ctrl);
        // Get origin
        Vector2i orig = {
          (p1.x < p2.x)?p1.x:p2.x,
          (p1.y < p2.y)?p1.y:p2.y,
        };
        // Get selection size
        Vector2i sel_size = {
          (p1.x > p2.x)?p1.x-p2.x:p2.x-p1.x,
          (p1.y > p2.y)?p1.y-p2.y:p2.y-p1.y,
        };
        // Ensure there is at least one cell selected
        if (!(sel_size.x == 0 || sel_size.y == 0)) {
          sel_data = std::move(world.getSelection(orig, sel_size));
          sel_ctrl = true;
        }
      }
    }
    if (!sel_ctrl) {
      patern_name[0] = '\0';
    }
    if (step_ctrl) {
      world.saveCompressed();
      rules.update();
      step_ctrl = false;
    }
    if (step_back_ctrl) {
      world.stepBack();
      step_back_ctrl = false;
    }

    if (apply_ctrl) {
      bool resize_needed = false;
      config_json["fps"] = fps_ctrl;
      if (config_json["screen_width"].get<int>() != width_ctrl ||
          config_json["screen_height"].get<int>() != height_ctrl) {
        config_json["screen_width"] = width_ctrl;
        config_json["screen_height"] = height_ctrl;
        rlImGuiShutdown();
        SetWindowSize(width_ctrl, height_ctrl);
        rlImGuiSetup(dark_theme_ctrl);
        resize_needed = true;
      }
      if (cell_size_ctrl != config_json["cell_size"].get<int>() ||
          resize_needed) {
        world.resize(config_json["screen_width"].get<int>() / cell_size_ctrl,
                     config_json["screen_height"].get<int>() / cell_size_ctrl);
        render.updateCellSize(cell_size_ctrl);
        rules.newWorld(&world);
        config_json["cell_size"] = cell_size_ctrl;
      }
      if (dark_theme_ctrl != config_json["dark_theme"]) {
        rlImGuiShutdown();
        rlImGuiSetup(dark_theme_ctrl);
        config_json["dark_theme"] = dark_theme_ctrl;
      }
      apply_ctrl = false;
      settings_window = false;
    }

    // Accumulate time and update simulation at the adjusted speed
    deltaTimeAccumulator += deltaTime;

    if (deltaTimeAccumulator >= timePerUpdate) {
      // Reset accumulator
      deltaTimeAccumulator -= timePerUpdate;
      if (menu_state == MenuState::PLAY) {
        world.saveCompressed();
        rules.update();
      }
    }
    BeginDrawing();
    ClearBackground(BLACK);
    render.display(&world);
    if (selecting) {
      auto grid_mouse = snapToGrid(mousePos, cell_size_ctrl);
      bool sel_x_less = (sel_pos.x < grid_mouse.x);
      bool sel_y_less = (sel_pos.y < grid_mouse.y);
      DrawRectangleLines(((sel_x_less)? sel_pos.x: grid_mouse.x), ((sel_y_less)? sel_pos.y: grid_mouse.y),
                        ((sel_x_less)? grid_mouse.x - sel_pos.x : sel_pos.x - grid_mouse.x),
                       ((sel_y_less)? grid_mouse.y - sel_pos.y : sel_pos.y - grid_mouse.y),
                        RED);
    }
    // Start ImGui frame
    rlImGuiBegin();

    bool control_panel_open = true;
    ImGuiWindowFlags control_panel_flags = ImGuiWindowFlags_AlwaysAutoResize |
                                           ImGuiWindowFlags_NoResize;
    ImVec2 menu_pos(3, 3);
    ImGui::SetNextWindowPos(menu_pos, ImGuiCond_Always);
    ImGui::Begin("Control Panel", &control_panel_open, control_panel_flags);
    ImGui::Checkbox("Play", &play_ctrl);
    if (ImGui::Button("Step")) {
      step_ctrl = true;
    }
    if (ImGui::Button("Step Back")) {
      step_back_ctrl = true;
    }
    ImGui::Checkbox("Edit", &edit_ctrl);
    ImGui::Checkbox("Clear", &clear_ctrl);
    ImGui::Checkbox("Randomize", &rand_ctrl);
    if (ImGui::Button((settings_window) ? "Hide settings" : "Show settings")) {
      settings_window = !settings_window;
    }
    ImGui::Text("Generation: %zu", world.getCycle());
    ImGui::End();

    if (settings_window) {
      ImGuiWindowFlags settings_flags =
          ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoResize;
      ImGui::Begin("Settings", &settings_window, settings_flags);
      ImGui::SliderInt("Window Width", &width_ctrl, 800, 1920);
      ImGui::SliderInt("Window Height", &height_ctrl, 600, 1200);
      ImGui::SliderInt("FPS", &fps_ctrl, 0, 30);
      ImGui::SliderInt("Cell Size", &cell_size_ctrl, 4, 100);
      ImGui::Checkbox("Dark Theme", &dark_theme_ctrl);
      if (ImGui::Button("Save & Apply")) {
        apply_ctrl = true;
      }
      ImGui::End();
    }
    if (sel_ctrl) {
      BeginTextureMode(selectionTexture);
      ClearBackground(BLACK);
      auto max_size = (sel_data[0] > sel_data[1]) ? sel_data[0] : sel_data[1];
      int fitted_width = 200 / max_size;
      auto sel_it = sel_data.begin();
      sel_it += 2; // skip dimensions
      for (int j = 0; j < sel_data[1]; j++) {
        for (int i = 0; i < sel_data[0]; i++) {
          if (*sel_it == 1) {
            DrawRectangle(i * fitted_width, (sel_data[1] -j-1) * fitted_width, fitted_width, fitted_width, WHITE);
          }
          sel_it++;
        }
      }
      EndTextureMode();
      ImGuiWindowFlags settings_flags =
          ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoResize;
      ImGui::Begin("Selection", &sel_ctrl, settings_flags);
      rlImGuiImageSize(&selectionTexture.texture, 200, 200);
      ImGui::InputText(sel_txt_input_hint.c_str(), patern_name, 255);
      if (ImGui::Button("Save")) {
        char path_buf[1024];
        ssize_t len = readlink("/proc/self/exe", path_buf, sizeof(path_buf)-1);
        if (len != -1) {
          // Create paterns dir if not present
          std::filesystem::path paterns_dir = std::filesystem::path(path_buf).parent_path() / "paterns";
          if (!std::filesystem::exists(paterns_dir) && !std::filesystem::create_directory(paterns_dir)) {
            std::cerr << "Failed to create paterns directory" << std::endl;
          } else { // Could be optimized by early returning in a function
            std::ofstream patern_file;
            paterns_dir += '/';
            paterns_dir += patern_name;
            patern_file.open(paterns_dir);
            if (!patern_file) {
              std::cerr << "Failed to create the patern file" << std::endl;
            } else {
              auto sel_it = sel_data.begin();
              sel_it += 2; // skip dimensions
              patern_file << sel_data[0];
              patern_file << "|"; // Separator needed to split as ascii values
              patern_file << sel_data[1];
              patern_file << "|"; // Separator needed to split as ascii values
              for (int j = 0; j < sel_data[1]; j++) {
                for (int i = 0; i < sel_data[0]; i++) {
                  patern_file << std::to_string(*sel_it);
                  if (*sel_it == 1) {
                  }
                  sel_it++;
                }
              }
              patern_file << std::flush;
              patern_file.close();
            }
          }
          sel_ctrl = false;
        }
      }
      ImGui::SameLine();
      if (ImGui::Button("Discard")) {
        sel_ctrl = false;
      }
      ImGui::End();
    }
    // End ImGui frame
    rlImGuiEnd();
    EndDrawing();
  }
  config_file.open(config_file_name, std::ios::out | std::ios::trunc);
  config_file << config_json.dump(2);
  config_file.close();
  // Cleanup Selection texture
  UnloadRenderTexture(selectionTexture);
  rlImGuiShutdown();
  CloseWindow();
  return 0;
}