#pragma once

#include <mbgl/map/change.hpp>

namespace mbgl {

class Map;

class Backend {
public:
    virtual ~Backend() = default;

    // Called when the backend's GL context needs to be made active or inactive. These are called,
    // as a matched pair, in four situations:
    //
    //   1. When releasing GL resources during Map destruction
    //   2. When calling a CustomLayerInitializeFunction, during Map::addLayer
    //   3. When calling a CustomLayerDeinitializeFunction, during Map::removeLayer
    //   4. When rendering for Map::renderStill
    //
    // They are *not* called for Map::render; it is assumed that the correct context is already
    // activated prior to calling Map::render.
    virtual void activate() = 0;
    virtual void deactivate() = 0;

    // Called when the map needs to be rendered; the backend should call Map::render() at some point
    // in the near future. (Not called for Map::renderStill() mode.)
    virtual void invalidate() = 0;

    // Notifies a watcher of map x/y/scale/rotation changes.
    virtual void notifyMapChange(MapChange change);
};

} // namespace mbgl