action_history.h

#ifndef ACTION_HISTORY_H
#define ACTION_HISTORY_H

#include "delta_t.h"
#include "piece_action.h"

#include <iosfwd>
#include <vector>

class action_history
{
public:
  action_history(
    const std::vector<std::pair<delta_t, piece_action>>& timed_actions  = {}
  );

  /// Add an action, when started
  void add_action(const delta_t& t, const piece_action& action) noexcept;

  const auto& get_timed_actions() const noexcept { return m_timed_actions; }

private:

  /// The history of actions (i.e when they started), in chrononical order
  std::vector<std::pair<delta_t, piece_action>> m_timed_actions;

};

/// Collect all the actions that started in the timespan
std::vector<piece_action> collect_actions_in_timespan(
  const action_history& history,
  const delta_t from,
  const delta_t to
);

/// Has this piece (i.e. a pawn) just finish a double move forward last time unit?
/// Only pawns can do this, e.g. e2-e4 or e7-e5
/// For example, when at t=0.5, e2-e4 is played,
/// from t=1.5 to t=2.5 this function will return true.
/// Before that, the piece was moving
/// After that, it was too long ago for en-passant
bool has_just_double_moved(
  const action_history& action_history,
  const delta_t when
);

const piece_action& get_last_action(const action_history& history);

bool has_actions(const action_history& history) noexcept;

/// Combine action histories and sort these
action_history merge_action_histories(const std::vector<action_history> histories);

/// Test this class and its free functions
void test_action_history();

std::string to_str(const action_history& history) noexcept;

std::ostream& operator<<(std::ostream& os, const action_history& history) noexcept;

#endif // ACTION_HISTORY_H