/* *****************************************************************************
 * The method lives() is based on Xitari's code, from Google Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * *****************************************************************************
 * A.L.E (Arcade Learning Environment)
 * Copyright (c) 2009-2013 by Yavar Naddaf, Joel Veness, Marc G. Bellemare and
 *   the Reinforcement Learning and Artificial Intelligence Laboratory
 * Released under the GNU General Public License; see License.txt for details.
 *
 * Based on: Stella  --  "An Atari 2600 VCS Emulator"
 * Copyright (c) 1995-2007 by Bradford W. Mott and the Stella team
 *
 * *****************************************************************************
 */

#include "games/supported/ChopperCommand.hpp"

#include "games/RomUtils.hpp"

namespace ale {
using namespace stella;

ChopperCommandSettings::ChopperCommandSettings() { reset(); }

/* create a new instance of the rom */
RomSettings* ChopperCommandSettings::clone() const {
  return new ChopperCommandSettings(*this);
}

/* process the latest information from ALE */
void ChopperCommandSettings::step(const System& system) {
  // update the reward
  reward_t score = getDecimalScore(0xEE, 0xEC, &system);
  score *= 100;
  m_reward = score - m_score;
  m_score = score;

  // update terminal status
  m_lives = readRam(&system, 0xE4) & 0xF;
  m_terminal = (m_lives == 0);
  /*
   * Memory address 0xC2 indicates whether the Chopper is pointed
   * left or right on the screen.
   *  - If the value is 0x00 we're looking left.
   *  - If the value ix 0x01 we are looking right.
   * At the beginning of the game when we're selecting the game mode
   * we are always facing left, therefore, 0xC2 == 0x00.
   * When the game starts the chopper is initialized facing
   * right, i.e., 0xC2 == 0x01. We know if the game has started
   * if at any point 0xC2 == 0x01 so we can just OR the LSB of 0xC2
   * to keep track of whether the game has started or not.
   *
   * */
  m_is_started |= readRam(&system, 0xC2) & 0x1;
}

/* is end of game */
bool ChopperCommandSettings::isTerminal() const {
  return (m_is_started && m_terminal);
};

/* get the most recently observed reward */
reward_t ChopperCommandSettings::getReward() const { return m_reward; }

/* is an action part of the minimal set? */
bool ChopperCommandSettings::isMinimal(const Action& a) const {
  switch (a) {
    case PLAYER_A_NOOP:
    case PLAYER_A_FIRE:
    case PLAYER_A_UP:
    case PLAYER_A_RIGHT:
    case PLAYER_A_LEFT:
    case PLAYER_A_DOWN:
    case PLAYER_A_UPRIGHT:
    case PLAYER_A_UPLEFT:
    case PLAYER_A_DOWNRIGHT:
    case PLAYER_A_DOWNLEFT:
    case PLAYER_A_UPFIRE:
    case PLAYER_A_RIGHTFIRE:
    case PLAYER_A_LEFTFIRE:
    case PLAYER_A_DOWNFIRE:
    case PLAYER_A_UPRIGHTFIRE:
    case PLAYER_A_UPLEFTFIRE:
    case PLAYER_A_DOWNRIGHTFIRE:
    case PLAYER_A_DOWNLEFTFIRE:
      return true;
    default:
      return false;
  }
}

/* reset the state of the game */
void ChopperCommandSettings::reset() {
  m_reward = 0;
  m_score = 0;
  m_terminal = false;
  m_lives = 3;
  m_is_started = false;
}

/* saves the state of the rom settings */
void ChopperCommandSettings::saveState(Serializer& ser) {
  ser.putInt(m_reward);
  ser.putInt(m_score);
  ser.putBool(m_terminal);
  ser.putInt(m_lives);
}

// loads the state of the rom settings
void ChopperCommandSettings::loadState(Deserializer& ser) {
  m_reward = ser.getInt();
  m_score = ser.getInt();
  m_terminal = ser.getBool();
  m_lives = ser.getInt();
}

// returns a list of mode that the game can be played in
ModeVect ChopperCommandSettings::getAvailableModes() {
  return {0, 2};
}

// set the mode of the game
// the given mode must be one returned by the previous function
void ChopperCommandSettings::setMode(
    game_mode_t m, System& system,
    std::unique_ptr<StellaEnvironmentWrapper> environment) {
  if (m == 0 || m == 2) {
    // read the mode we are currently in
    unsigned char mode = readRam(&system, 0xE0);
    // press select until the correct mode is reached
    while (mode != m) {
      environment->pressSelect(2);
      mode = readRam(&system, 0xE0);
    }
    //reset the environment to apply changes.
    environment->softReset();
  } else {
    throw std::runtime_error("This mode doesn't currently exist for this game");
  }
}

DifficultyVect ChopperCommandSettings::getAvailableDifficulties() {
  return {0, 1};
}

}  // namespace ale
