/*
 * SPDX-FileCopyrightText: Dora "cat" <cat@thenight.club>
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public License,
 * v. 2.0. If a copy of the MPL was not distributed with this file, You can
 * obtain one at http://mozilla.org/MPL/2.0/.
 */

#ifndef GUARD_VARIADICMACHINE_MACHINE_H
#define GUARD_VARIADICMACHINE_MACHINE_H

#include <array>
#include <cstdarg>
#include <cstddef>
#include <cstdint>
#include <exception>
#include <iostream>

namespace VariadicMachine {
enum Command : int16_t {
  // Single Argument
  NoCommand,
  MoveLeft,
  MoveRight,
  Increment,
  Decrement,
  PrintAsCharacter,

  // Two Arguments
  IncrementBy,
  DecrementBy
};

template <std::size_t maxCells = 2048> class VMachine {
public:
  template <typename... Commands> constexpr void Do(Commands &&...commands) {
    (Execute(commands), ...);
  }

private:
  Command State = Command::NoCommand;
  std::array<std::int16_t, maxCells> memory;
  std::int16_t W = 0, X = 0, Y = 0, Z = 0;
  std::size_t maxCellLimit = maxCells, currentPosition = 0;

  void Execute(int16_t command) {
    switch (State) {
    case Command::IncrementBy:
      memory[currentPosition] += command;
      State = Command::NoCommand;
      return;

    case Command::DecrementBy:
      memory[currentPosition] -= command;
      State = Command::NoCommand;
      return;

    default:
      std::terminate();
      break;

    case Command::NoCommand:
      break;
    }

    // State: NoCommand
    switch (command) {
    case Command::MoveLeft:
      --currentPosition;
      return;
    case Command::MoveRight:
      ++currentPosition;
      return;

    case Command::Increment:
      ++memory[currentPosition];
      return;
    case Command::Decrement:
      --memory[currentPosition];
      return;

    case Command::PrintAsCharacter:
      std::wcout << static_cast<wchar_t>(memory[currentPosition]);
      return;

    // Double Argument Commands
    case Command::IncrementBy:
    case Command::DecrementBy:
      State = static_cast<Command>(command);
      return;

    default:
      std::cout << "Here\n";
      std::terminate();
      return;
    }
  }
};
} // namespace VariadicMachine
#endif