#pragma once

#include <vector>
#include <memory>
#include "timeline.h"
#include <SFML/Audio/Music.hpp>

class ClassicNote;
class ClassicViewManager;

class ClassicTimeline : public Timeline
{
public:
    explicit ClassicTimeline();
    virtual ~ClassicTimeline();
    virtual void update() override;
    virtual void init() override;
    virtual void clear() override;

    virtual microsec currentMusicOffset() const override;
    virtual void drawVisibleNotes(sf::RenderWindow& window) const override;

    void fetchVisibleNotes(const std::unique_ptr<ClassicViewManager>& view_manager);

    using Iterator = std::vector<ClassicNote*>::const_iterator;

    Iterator getActiveNote() noexcept;

    bool isExpired(const Iterator& iterator) const;
    void expire(Iterator& iterator);

private:
    std::vector<ClassicNote*> _timeline;
    Iterator _top_note;
    Iterator _active_note;
    Iterator _last_visible_note;

    microsec _visibility_offset;

    sf::Music _music;

    void checkCurrentActiveNote(const microsec &music_offset);
    void checkForNextActiveNote(const microsec &music_offset);
    void discardExpiredNotes(const std::unique_ptr<ClassicViewManager>& view_manager, const microsec &music_offset);
    bool isVisiblyClose(const Iterator& iterator, const microsec& music_offset) const;

    /* 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.
     *                                         */
};