/** \ingroup gui
 * \class QgsLayerTreeEmbeddedWidgetProvider
 * Provider interface to be implemented in order to introduce new kinds of embedded widgets for use in layer tree.
 * Embedded widgets are assigned per individual map layers and they are shown before any legend entries.
 * @see QgsLayerTreeEmbeddedWidgetRegistry
 * @note introduced in QGIS 2.16
 */
class QgsLayerTreeEmbeddedWidgetProvider
{
%TypeHeaderCode
#include <qgslayertreeembeddedwidgetregistry.h>
%End

  public:
    virtual ~QgsLayerTreeEmbeddedWidgetProvider();

    //! Unique name of the provider (among other providers)
    virtual QString id() const = 0;

    //! Human readable name - may be translatable with tr()
    virtual QString name() const = 0;

    //! Factory to create widgets. The returned widget is owned by the caller.
    //! The widgetIndex argument may be used to identify which widget is being
    //! created (useful when using multiple widgets from the same provider for one layer).
    virtual QWidget *createWidget( QgsMapLayer *layer, int widgetIndex ) = 0 /Factory/;

    //! Whether it makes sense to use this widget for a particular layer
    virtual bool supportsLayer( QgsMapLayer *layer ) = 0;
};

/** \ingroup gui
 * \class QgsLayerTreeEmbeddedWidgetRegistry
 * Registry of widgets that may be embedded into layer tree view.
 * Embedded widgets are assigned per individual map layers and they are shown before any legend entries.
 * Layer tree must have UseEmbeddedWidgets flag enabled in order to show assigned widgets.
 *
 * @see QgsLayerTreeEmbeddedWidgetRegistry
 * @note introduced in QGIS 2.16
 */
class QgsLayerTreeEmbeddedWidgetRegistry
{
%TypeHeaderCode
#include <qgslayertreeembeddedwidgetregistry.h>
%End

  public:

    QgsLayerTreeEmbeddedWidgetRegistry();

    ~QgsLayerTreeEmbeddedWidgetRegistry();

    /** Return list of all registered providers */
    QStringList providers() const;

    /** Get provider object from the provider's ID */
    QgsLayerTreeEmbeddedWidgetProvider *provider( const QString &providerId ) const;

    /** Register a provider, takes ownership of the object.
     * Returns true on success, false if the provider is already registered. */
    bool addProvider( QgsLayerTreeEmbeddedWidgetProvider *provider /Transfer/ );

    /** Unregister a provider, the provider object is deleted.
     * Returns true on success, false if the provider was not registered. */
    bool removeProvider( const QString &providerId );

  private:

    QgsLayerTreeEmbeddedWidgetRegistry( const QgsLayerTreeEmbeddedWidgetRegistry &other );
};