#include "classictimeline.h"
#include "classicnotemanager.h"
#include <iostream>

ClassicTimeline::ClassicTimeline(const std::shared_ptr<ClassicNoteManager>& manager) :
    _note_manager(manager),
    _current_offset(0)
{}

void ClassicTimeline::setNotes(std::vector<ClassicNote *> &&notes, const microsec &visibility)
{
    _visibility_offset = visibility;
    _timeline = std::move(notes);

    _top_note = _timeline.begin();
    expire(_first_visible_note);
    expire(_last_visible_note);
    expire(_active_note);

    fetchVisibleNotes();
}

ClassicTimeline::~ClassicTimeline()
{
    clear();
}

void ClassicTimeline::clear()
{
    for (auto& note : _timeline)
        delete note;

    _timeline.clear();
}

void ClassicTimeline::update(const microsec& offset)
{
    _current_offset = offset;

    checkCurrentActiveNote();
    checkForNextActiveNote();
    updateVisibleSprites(_current_offset);
}

void ClassicTimeline::checkCurrentActiveNote()
{
    if (isExpired(_active_note))
        return;

    auto note = *_active_note;

    if (!_note_manager->isActive(note))
    {
        expire(_active_note);
        ++_top_note;
    }
}

void ClassicTimeline::checkForNextActiveNote()
{
    if (!isExpired(_active_note))
        return;

    auto top_note = *_top_note;
    if (_note_manager->isActive(top_note))
        _active_note = _top_note;
}

void ClassicTimeline::updateVisibleSprites(const microsec& music_offset)
{
    if (nothingToDraw())
        return;

    const auto& note_manager = _note_manager;
    std::for_each(_first_visible_note, _last_visible_note,
                  [&note_manager, &music_offset](const auto& note)
                  {
                      note_manager->update(note, music_offset);
                  });
}

ClassicTimeline::Iterator ClassicTimeline::getActiveNote() noexcept
{
    return _active_note;
}

bool ClassicTimeline::isExpired(const Iterator& iterator) const
{
    return iterator == _timeline.end();
}

void ClassicTimeline::expire(Iterator& iterator)
{
    iterator = _timeline.end();
}

bool ClassicTimeline::isVisiblyClose(const Iterator& iterator, const microsec& music_offset) const
{
    return ((*iterator)->evaluator.offset() - _visibility_offset) <= music_offset;
}

void ClassicTimeline::fetchVisibleNotes()
{
    findLastVisibleNote(_current_offset);
    findFirstVisibleNote();
}

void ClassicTimeline::findLastVisibleNote(const microsec &music_offset)
{
    Iterator note_iterator = _top_note;
    while (isVisiblyClose(note_iterator, music_offset))
    {
        if (nothingToDraw())
            _first_visible_note = note_iterator;

        auto note = *note_iterator;

        if (!_note_manager->isInGame(note))
            _note_manager->putToGame(note, music_offset);

        ++note_iterator;
    }

    _last_visible_note = note_iterator;
}

void ClassicTimeline::findFirstVisibleNote()
{
    if (nothingToDraw())
        return;

    auto note_iterator = _first_visible_note;
    while (note_iterator != _last_visible_note)
    {
        auto note = *note_iterator;
        if (_note_manager->shouldRemove(note))
            ++_first_visible_note;

        ++note_iterator;
    }
}

bool ClassicTimeline::nothingToDraw() const noexcept
{
    return isExpired(_first_visible_note);
}

void ClassicTimeline::drawVisibleNotes() const
{
    if (nothingToDraw())
        return;

    const auto& note_manager = _note_manager;
    std::for_each(_first_visible_note, _last_visible_note,
                  [&note_manager](const auto& note)
                  {
                      note_manager->draw(note);
                  });
}