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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2024                                                               *
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#ifndef __OPENSPACE_CORE___WAYPOINT___H__
#define __OPENSPACE_CORE___WAYPOINT___H__

#include <openspace/camera/camerapose.h>
#include <ghoul/glm.h>
#include <optional>
#include <string>

namespace openspace { class SceneGraphNode; }

namespace openspace::interaction {

struct NavigationState;

class Waypoint {
public:
    Waypoint() = default;
    Waypoint(const glm::dvec3& pos, const glm::dquat& rot, const std::string& ref);
    explicit Waypoint(const NavigationState& ns);

    CameraPose pose() const;
    glm::dvec3 position() const;
    glm::dquat rotation() const;
    SceneGraphNode* node() const;
    std::string nodeIdentifier() const;
    std::optional<std::string> aimIdentifier() const;
    double validBoundingSphere() const;

private:
    CameraPose _pose;
    std::string _nodeIdentifier;
    // To be able to handle nodes with faulty bounding spheres
    double _validBoundingSphere = 0.0;

    // Keep track of if there was an aim node, specified in for example the
    // navigation state used to create this waypoint. It may be required in
    // certain situations
    std::optional<std::string> _aimNodeIdentifier;
};

/**
 * Compute a waypoint from the current camera position.
 *
 * \return The computed WayPoint
 */
Waypoint waypointFromCamera();

struct NodeCameraStateSpec {
    std::string identifier;
    std::optional<glm::dvec3> position;
    std::optional<double> height;
    bool useTargetUpDirection = false;
};

// @TODO (2023-05-16, emmbr) Allow different light sources, not only the 'Sun'
/**
 * Compute a waypoint from information about a scene graph node and a previous waypoint,
 * where the camera will be facing the given node. If there is a 'Sun' node in the scene,
 * it will possibly be used to compute a position on the lit side of the object.
 *
 * \param spec Details about the node and state to create the waypoint from. Minimal
 *             information is the identifier of the node, but a position or height above
 *             the bounding sphere may also be given.
 * \param startPoint An optional previous waypoint. If not specified, the current camera
 *                   position will be used.
 * \param useLinear If `true`, the new waypoint will be computed along a straight line
 *                  from the start waypoint to the scene graph node or position.
 * \return The computed WayPoint
 */
Waypoint computeWaypointFromNodeInfo(const NodeCameraStateSpec& spec,
    std::optional<Waypoint> startPoint = std::nullopt, bool useLinear = false);

} // namespace openspace::interaction

#endif // __OPENSPACE_CORE___WAYPOINT___H__