#pragma once
#include "vde/brep/feature_tree.h"
#include <functional>
#include <string>
#include <vector>

namespace vde::brep {

/// Callback type for model changes.
/// Receives the feature name and the new model after rebuild.
using UpdateCallback = std::function<void(const std::string& feature_name, const BrepModel& new_model)>;

/**
 * @brief Notifies listeners when features change.
 *
 * Integrates with FeatureHistory: after each apply/undo/redo,
 * call notify() to push the updated model to all registered callbacks.
 *
 * @ingroup brep
 */
class UpdateNotifier {
public:
    /// Register a callback. Called on every notify().
    void on_update(UpdateCallback cb) { callbacks_.push_back(std::move(cb)); }

    /// Notify all registered listeners.
    void notify(const std::string& feature, const BrepModel& model) {
        for (auto& cb : callbacks_) cb(feature, model);
    }

    /// Remove all callbacks.
    void clear() { callbacks_.clear(); }

    /// Number of registered callbacks.
    [[nodiscard]] size_t listener_count() const { return callbacks_.size(); }

private:
    std::vector<UpdateCallback> callbacks_;
};

} // namespace vde::brep