cpp-dice-roller/include/dice-roll/roll.h

//
//  roll.hpp
//  dice-roll
//
//  Created by Sam Jaffe on 12/1/18.
//  Copyright © 2018 Sam Jaffe. All rights reserved.
//

#pragma once

#include <vector>

#include "die.h"
#include "random.h"

namespace dice {
enum class outcome {
  PASS,
  FAIL,
};

struct die_outcome {
  friend auto operator<=>(die_outcome const &, die_outcome const &) = default;

  int roll;
  int sides;
};

// Describe the actual result of rolling (+/-)NdM
struct die_roll {
  // Collapse this roll into its actual value
  operator int() const;
  // Is this being added, or subtracted from the total
  sign sign;
  // Since this roll was composed on NdM, rolled.size() == N. Each element
  // of rolled is within the integer range [1, M].
  std::vector<die_outcome> rolled;
};

// Describe the actual result of rolling an arbitrary set of dice with mods
struct dice_roll {
  // Collapse this roll into its actual value
  operator int() const;
  std::variant<int, outcome> result() const;
  // A vector of component roll results, each on representing a single NdM
  // expression.
  std::vector<die_roll> sub_rolls;
  // A vector of every modifier attached to the system.
  std::vector<mod> modifiers;
  difficulty_class dc;
};

class roller {
public:
  roller();
  roller(engine::random && g);

  /**
   * @param d Some dice roll structure, containing any number of dice sets 'NdM'
   * as well as any number of roll modifiers (fixed numbers). Additionally,
   * can contain a repetition parameter.
   * @return A vector of actualized rolls, where `vector.size() == d.num`.
   */
  std::vector<dice_roll> operator()(dice const & d);

private:
  engine::random gen;
};

/**
 * Print out the component elements of an actualized dice roll.
 * Use instead `out << int(r)` to print the final summation.
 */
std::ostream & operator<<(std::ostream & out, dice_roll const & r);
}