project-kyoku/timeline.h

#ifndef TIMELINE_H
#define TIMELINE_H

#include <SFML/Config.hpp>

#include <vector>
#include <memory>

using microsec = sf::Int64;
class Note;

class Timeline
{
public:
    explicit Timeline();
    ~Timeline();

    void update(const microsec& microseconds);
    const Note* fetchActiveNote(const microsec &microseconds) noexcept;

private:
    std::vector<Note*> _timeline;
    std::vector<Note*>::iterator _top_note;
    Note* _active_note;

    void checkCurrentActiveNote(const microsec &microseconds);
    void checkForNextActiveNote(const microsec &microseconds);

    /* Difference between top and active note is that
     * top note is the note handling input right now
     * OR it's the closest note from current music offset
     * position, not necessarily active. A note stops being top only
     * after dying or being tapped by player, even if it's already
     * past her perfect offset.
     *
     * Meanwhile active note is the note which is currently handling
     *     player input for grade.
     *
     * An active note is always top note but a top note
     *    is not always active note.
     *                                         */
};

#endif // TIMELINE_H