LoopState.h

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#pragma once
 
#include "QGCState.h"
 
#include <functional>
 
template<typename T>
class LoopState : public QGCState
{
public:
    using ItemAction = std::function<void(const T& item, int index)>;
    using ItemPredicate = std::function<bool(const T& item, int index)>;
 
    LoopState(const QString& stateName, QState* parent,
              const QList<T>& items, ItemAction action)
        : QGCState(stateName, parent)
        , _items(items)
        , _action(std::move(action))
    {
    }
 
    void setFilter(ItemPredicate filter) { _filter = std::move(filter); }
 
    int currentIndex() const { return _currentIndex; }
 
    T currentItem() const { return _currentIndex >= 0 && _currentIndex < _items.size()
                                   ? _items[_currentIndex] : T(); }
 
    int totalItems() const { return _items.size(); }
 
    int processedCount() const { return _processedCount; }
 
protected:
    void onEnter() override
    {
        _currentIndex = -1;
        _processedCount = 0;
        _processNextItem();
    }
 
private:
    void _processNextItem()
    {
        _currentIndex++;
 
        // Skip filtered items
        while (_currentIndex < _items.size() && _filter && !_filter(_items[_currentIndex], _currentIndex)) {
            _currentIndex++;
        }
 
        if (_currentIndex >= _items.size()) {
            // All items processed
            emit advance();
            return;
        }
 
        // Process current item
        if (_action) {
            _action(_items[_currentIndex], _currentIndex);
        }
        _processedCount++;
 
        // Schedule next item processing (allow event loop to process)
        QMetaObject::invokeMethod(this, &LoopState::_processNextItem, Qt::QueuedConnection);
    }
 
    QList<T> _items;
    ItemAction _action;
    ItemPredicate _filter;
    int _currentIndex = -1;
    int _processedCount = 0;
};