#include "Game.h"
#include <RmlUi/Core/DataModelHandle.h>
#include <RmlUi/Core/Types.h>
#include <raylib.h>

namespace {

const char *DocumentPathFor(GameState state) {
  switch (state) {
  case START_MENU:
    return "assets/main-menu.rml";
  case PAUSE_MENU:
    return "assets/pause-menu.rml";
  case STATS_MENU:
    return "assets/stats-menu.rml";
  case OPTIONS_MENU:
    return "assets/options-menu.rml";
  case IN_GAME:
    return "assets/game-ui.rml";
  }
  return nullptr;
}

bool IsMenuState(GameState state) {
  return state == OPTIONS_MENU || state == STATS_MENU;
}

} // namespace

bool Game::Init(Rml::Context *context) {
  if (!context)
    return false;
  ctx = context;
  return true;
}

bool Game::SetupRmlDataBinding(Rml::DataModelHandle &model_handle) {
  Rml::DataModelConstructor dmc = ctx->CreateDataModel("game_data");
  if (!dmc) {
    TraceLog(LOG_ERROR, "Failed to construct data model.");
    return false;
  }

  // ---------- Member bindings ----------

  dmc.Bind("game_state", &game_data.game_state);

  // ---------- Event callback bindings ----------

  dmc.BindEventCallback("start_game", [this](Rml::DataModelHandle, Rml::Event &,
                                             const Rml::VariantList &) {
    TrySetGameState(IN_GAME);
  });

  dmc.BindEventCallback("pause_game", [this](Rml::DataModelHandle, Rml::Event &,
                                             const Rml::VariantList &) {
    TrySetGameState(PAUSE_MENU);
  });

  dmc.BindEventCallback(
      "unpause_game",
      [this](Rml::DataModelHandle, Rml::Event &, const Rml::VariantList &) {
        TrySetGameState(IN_GAME);
      });

  dmc.BindEventCallback(
      "open_options_menu",
      [this](Rml::DataModelHandle, Rml::Event &, const Rml::VariantList &) {
        TrySetGameState(OPTIONS_MENU);
      });

  dmc.BindEventCallback(
      "end_current_game",
      [this](Rml::DataModelHandle, Rml::Event &, const Rml::VariantList &) {
        TrySetGameState(START_MENU);
      });

  dmc.BindEventCallback("go_back",
                        [this](Rml::DataModelHandle, Rml::Event &,
                               const Rml::VariantList &) { GoBack(); });

  model_handle = dmc.GetModelHandle();
  return true;
}

Rml::ElementDocument *Game::LoadOrGetDocument(GameState state) {
  if (auto it = documents.find(state); it != documents.end())
    return it->second;

  const char *path = DocumentPathFor(state);
  if (!path)
    return nullptr;

  Rml::ElementDocument *doc = ctx->LoadDocument(path);
  if (!doc) {
    TraceLog(LOG_ERROR, "Failed to load document: %s", path);
    return nullptr;
  }

  documents[state] = doc;
  return doc;
}

void Game::ShowDocumentForState(GameState state) {
  if (activeDocument) {
    activeDocument->Hide();
    activeDocument = nullptr;
  }

  if (Rml::ElementDocument *doc = LoadOrGetDocument(state)) {
    doc->Show();
    activeDocument = doc;
  }
}

void Game::TrySetGameState(GameState newState) {
  GameState currentState = CurrentState();

  if (IsMenuState(newState) && !IsMenuState(currentState)) {
    previousState = currentState;
  }

  switch (newState) {
  case START_MENU:
    if (currentState == IN_GAME)
      ResetGame();
    break;
  case IN_GAME:
    if (currentState == START_MENU)
      StartNewGame();
    break;
  default:
    break;
  }

  game_data.game_state = newState;
  ShowDocumentForState(newState);
}

void Game::GoBack() {
  if (IsMenuState(CurrentState())) {
    TrySetGameState(previousState);
  }
}

void Game::StartNewGame() {
  // TODO

  // --- placeholder testing stuff ---
  playerPos = {GetScreenWidth() / 2.0f, GetScreenHeight() / 2.0f};
}

void Game::ResetGame() {
  // TODO
}

void Game::Update() {
  HandleInput();

  if (CurrentState() != IN_GAME)
    return;
  // TODO

  // --- placeholder testing stuff ---
  float dt = GetFrameTime();

  if (IsKeyDown(KEY_W) || IsKeyDown(KEY_UP))
    playerPos.y -= playerSpeed * dt;
  if (IsKeyDown(KEY_S) || IsKeyDown(KEY_DOWN))
    playerPos.y += playerSpeed * dt;
  if (IsKeyDown(KEY_A) || IsKeyDown(KEY_LEFT))
    playerPos.x -= playerSpeed * dt;
  if (IsKeyDown(KEY_D) || IsKeyDown(KEY_RIGHT))
    playerPos.x += playerSpeed * dt;
}

void Game::Draw2D() {
  if (CurrentState() != IN_GAME)
    return;
  // TODO

  // --- placeholder testing stuff ---
  // DrawText("Hello from raylib!", 50, 50, 20, RAYWHITE);
  if (CurrentState() != IN_GAME)
    return;
  DrawCircleV(playerPos, 24.0f, BLUE);
  DrawText("WASD/Arrows to move, ESC to pause", 20, 20, 20, RAYWHITE);
}

void Game::HandleInput() {
  if (!IsKeyReleased(KEY_ESCAPE))
    return;

  switch (CurrentState()) {
  case IN_GAME:
    TrySetGameState(PAUSE_MENU);
    break;
  case PAUSE_MENU:
    TrySetGameState(IN_GAME);
    break;
  case OPTIONS_MENU:
  case STATS_MENU:
    GoBack();
    break;
  default:
    break;
  }
}