// -*-c++-*-
// SPDX-License-Identifier: LGPL-2.1-only
// Copyright (C) 2021 James Hogan <james@albanarts.com>

#ifndef OSGXR_Action
#define OSGXR_Action 1

#include <osgXR/Export>

#include <osg/Quat>
#include <osg/Referenced>
#include <osg/Vec2f>
#include <osg/Vec3f>

#include <cstdint>
#include <memory>
#include <string>
#include <vector>

namespace osgXR {

class ActionSet;
class Subaction;

/**
 * Represents an OpenXR action.
 * OpenXR actions are inputs & outputs which are abstracted from the physical
 * input sources. The OpenXR runtime is responsible for binding them to sources,
 * using suggested bindings in interaction profiles.
 *
 * These Action objects can persist across multiple VR sessions, and changes can
 * be made at any time, however some changes won't take effect while a session
 * is running.
 */
class OSGXR_EXPORT Action : public osg::Referenced
{
    public:

        class Private;

    protected:

        /// Constructor (internal).
        Action(Private *priv);

    public:

        /// Destructor.
        ~Action();

        /**
         * Add a subaction that may be later queried.
         * Any subaction that is intended to be queried must be added to the
         * action first.
         * @param subaction Subaction that may be later queried.
         */
        void addSubaction(Subaction *subaction);

        // Accessors

        /**
         * Set the action's name and localized name.
         * @param name          New name for OpenXR action.
         * @param localizedName A localized version of @p name.
         */
        void setName(const std::string &name,
                     const std::string &localizedName);

        /**
         * Set the action's name.
         * @param name New name for OpenXR action.
         */
        void setName(const std::string &name);
        /// Get the action's name.
        const std::string &getName() const;

        /**
         * Set the action's localized name.
         * @param localizedName The localized name for the action.
         */
        void setLocalizedName(const std::string &localizedName);
        /// Get the action's localized name.
        const std::string &getLocalizedName() const;

        /**
         * Get a list of currently bound source paths for this action.
         * @param sourcePaths[out] Vector of source paths to write into.
         */
        void getBoundSources(std::vector<std::string> &sourcePaths) const;

        typedef enum {
            // Must match XR_INPUT_SOURCE_LOCALIZED_NAME_*
            /// Include user path (e.g. "Left Hand").
            USER_PATH_BIT = 1,
            /// Include interaction profile (e.g. "Vive Controller").
            INTERACTION_PROFILE_BIT = 2,
            /// Include input component (e.g. "Trigger").
            COMPONENT_BIT = 4,
        } LocalizedNameFlags;

        /**
         * Get a list of currently bound source localized names for this action.
         * @param whichComponents  Which components to include.
         * @param names[out] Vector of names to write into.
         */
        void getBoundSourcesLocalizedNames(uint32_t whichComponents,
                                           std::vector<std::string> &names) const;

    private:

        std::unique_ptr<Private> _private;

        // Copying not permitted
        Action(const Action &copy);
};

/// An action that can only have boolean values.
class OSGXR_EXPORT ActionBoolean : public Action
{
    public:

        /**
         * Construct a boolean action.
         * @param actionSet The action set the action should belong to.
         */
        ActionBoolean(ActionSet *actionSet);

        /**
         * Construct a boolean action.
         * @param actionSet The action set the action should belong to.
         * @param name      The name of the OpenXR action, also used as the
         *                  localized name.
         */
        ActionBoolean(ActionSet *actionSet,
                      const std::string &name);

        /**
         * Construct a boolean action.
         * @param actionSet     The action set the action should belong to.
         * @param name          The name of the OpenXR action.
         * @param localizedName The localized name for the action.
         */
        ActionBoolean(ActionSet *actionSet,
                      const std::string &name,
                      const std::string &localizedName);

        /**
         * Get the current value of the action as a bool.
         * @param subaction The subaction to filter sources from, which must
         *                  have been specified to Action::addSubaction().
         * @return The current value of the action.
         */
        bool getValue(Subaction *subaction = nullptr);
};

/// An action that can have floating point values.
class OSGXR_EXPORT ActionFloat : public Action
{
    public:

        /**
         * Construct a floating-point action.
         * @param actionSet The action set the action should belong to.
         */
        ActionFloat(ActionSet *actionSet);

        /**
         * Construct a floating-point action.
         * @param actionSet The action set the action should belong to.
         * @param name      The name of the OpenXR action, also used as the
         *                  localized name.
         */
        ActionFloat(ActionSet *actionSet,
                    const std::string &name);

        /**
         * Construct a floating-point action.
         * @param actionSet     The action set the action should belong to.
         * @param name          The name of the OpenXR action.
         * @param localizedName The localized name for the action.
         */
        ActionFloat(ActionSet *actionSet,
                    const std::string &name,
                    const std::string &localizedName);

        /**
         * Get the current value of the action as a float.
         * @param subaction The subaction to filter sources from, which must
         *                  have been specified to Action::addSubaction().
         * @return The current value of the action.
         */
        float getValue(Subaction *subaction = nullptr);
};

/// An action that can have 2 dimentional floating point vector values.
class OSGXR_EXPORT ActionVector2f : public Action
{
    public:

        /**
         * Construct a 2d floating-point vector action.
         * @param actionSet The action set the action should belong to.
         */
        ActionVector2f(ActionSet *actionSet);

        /**
         * Construct a 2d floating-point vector action.
         * @param actionSet The action set the action should belong to.
         * @param name      The name of the OpenXR action, also used as the
         *                  localized name.
         */
        ActionVector2f(ActionSet *actionSet,
                       const std::string &name);

        /**
         * Construct a 2d floating-point vector action.
         * @param actionSet     The action set the action should belong to.
         * @param name          The name of the OpenXR action.
         * @param localizedName The localized name for the action.
         */
        ActionVector2f(ActionSet *actionSet,
                       const std::string &name,
                       const std::string &localizedName);

        /**
         * Get the current value of the action as an OSG vector.
         * @param subaction The subaction to filter sources from, which must
         *                  have been specified to Action::addSubaction().
         * @return The current value of the action.
         */
        osg::Vec2f getValue(Subaction *subaction = nullptr);
};

/// An action that can have pose (position and orientation) values.
class OSGXR_EXPORT ActionPose : public Action
{
    public:

        /**
         * Construct a pose action.
         * @param actionSet The action set the action should belong to.
         */
        ActionPose(ActionSet *actionSet);

        /**
         * Construct a pose action.
         * @param actionSet The action set the action should belong to.
         * @param name      The name of the OpenXR action, also used as the
         *                  localized name.
         */
        ActionPose(ActionSet *actionSet,
                   const std::string &name);

        /**
         * Construct a pose action.
         * @param actionSet     The action set the action should belong to.
         * @param name          The name of the OpenXR action.
         * @param localizedName The localized name for the action.
         */
        ActionPose(ActionSet *actionSet,
                   const std::string &name,
                   const std::string &localizedName);

        /**
         * Represents a pose action's position and orientation.
         * This represents a pose action's position and orientation, along with
         * flags to indicate whether each of these are valid and whether they're
         * currently tracked (as opposed to estimated based on recent tracking).
         */
        class OSGXR_EXPORT Location
        {
            public:

                typedef enum {
                    // Must match XR_SPACE_LOCATION_* */
                    ORIENTATION_VALID_BIT   = 0x1,
                    POSITION_VALID_BIT      = 0x2,
                    ORIENTATION_TRACKED_BIT = 0x4,
                    POSITION_TRACKED_BIT    = 0x8,
                } Flags;

                // Constructors

                /// Construct a pose action location.
                Location();
                /// Construct a pose action location.
                Location(Flags flags,
                         const osg::Quat &orientation,
                         const osg::Vec3f &position);

                // Accessors

                /**
                 * Find whether the orientation is valid.
                 * If not, the orientation is undefined.
                 * @return Whether the orientation is valid.
                 */
                bool isOrientationValid() const
                {
                    return _flags & ORIENTATION_VALID_BIT;
                }

                /**
                 * Find whether the position is valid.
                 * If not, the position is undefined.
                 * @return Whether the position is valid.
                 */
                bool isPositionValid() const
                {
                    return _flags & POSITION_VALID_BIT;
                }

                /**
                 * Find whether the orientation is being tracked.
                 * If not, the orientation may only be an estimate.
                 * @return Whether the orientation is being tracked.
                 */
                bool isOrientationTracked() const
                {
                    return _flags & ORIENTATION_TRACKED_BIT;
                }

                /**
                 * Find whether the position is being tracked.
                 * If not, the position may only be an estimate.
                 * @return Whether the position is being tracked.
                 */
                bool isPositionTracked() const
                {
                    return _flags & POSITION_TRACKED_BIT;
                }

                /// Get the flags which indicate validity and tracking.
                Flags getFlags() const
                {
                    return _flags;
                }

                /**
                 * Get the pose action's orientation as a quaternion.
                 * Get the pose action's orientation relative to the default
                 * reference space as an OSG quaternion.
                 *
                 * The orientation is undefined if isOrientationValid() returns
                 * false.
                 *
                 * The orientation may only be an estimate if
                 * isOrientationTracked() returns false.
                 */
                const osg::Quat &getOrientation() const
                {
                    return _orientation;
                }

                /**
                 * Get the pose action's position as a 3D vector.
                 * Get the pose action's position relative to the default
                 * reference space as an OSG 3D vector.
                 *
                 * The position is undefined if isPositionValid() returns false.
                 *
                 * The position may only be an estimate if isPositionTracked()
                 * returns false.
                 */
                const osg::Vec3f &getPosition() const
                {
                    return _position;
                }

                // Comparison operators

                bool operator != (const Location &other) const
                {
                    return _flags != other._flags ||
                           (isOrientationValid() && _orientation != other._orientation) ||
                           (isPositionValid() && _position != other._position);
                }

                bool operator == (const Location &other) const
                {
                    return !operator != (other);
                }

            protected:

                Flags _flags;
                osg::Quat _orientation;
                osg::Vec3f _position;
        };

        /**
         * Get the current pose of the action as a Location object.
         * @param subaction The subaction to filter sources from, which must
         *                  have been specified to Action::addSubaction().
         * @return The current pose of the action.
         */
        Location getValue(Subaction *subaction = nullptr);
};

/// An output action for vibration.
class OSGXR_EXPORT ActionVibration : public Action
{
    public:

        /**
         * Construct a vibration output action.
         * @param actionSet The action set the action should belong to.
         */
        ActionVibration(ActionSet *actionSet);

        /**
         * Construct a vibration output action.
         * @param actionSet The action set the action should belong to.
         * @param name      The name of the OpenXR action, also used as the
         *                  localized name.
         */
        ActionVibration(ActionSet *actionSet,
                        const std::string &name);

        /**
         * Construct a vibration output action.
         * @param actionSet     The action set the action should belong to.
         * @param name          The name of the OpenXR action.
         * @param localizedName The localized name for the action.
         */
        ActionVibration(ActionSet *actionSet,
                        const std::string &name,
                        const std::string &localizedName);

        enum {
            /// Indicates a minimum supported durection for a haptic device.
            DURATION_MIN = -1,
            /// Indicates an optimal frequency for a haptic pulse.
            FREQUENCY_UNSPECIFIED = 0,
        };

        /**
         * Apply haptic feedback.
         * @param duration_ns Duration of vibration in nanoseconds.
         * @param frequency   Frequency of vibration in Hz.
         * @param amplitude   Amplitude of vibration between 0.0 and 1.0.
         * @return true on success, false otherwise.
         */
        bool applyHapticFeedback(int64_t duration_ns, float frequency,
                                 float amplitude);

        /**
         * Apply haptic feedback.
         * @param subaction   The subaction to apply haptics to, which must
         *                    have been specified to Action::addSubaction().
         * @param duration_ns Duration of vibration in nanoseconds.
         * @param frequency   Frequency of vibration in Hz.
         * @param amplitude   Amplitude of vibration between 0.0 and 1.0.
         * @return true on success, false otherwise.
         */
        bool applyHapticFeedback(Subaction *subaction,
                                 int64_t duration_ns, float frequency,
                                 float amplitude);

        /**
         * Stop any in-progress haptic feedback.
         * @param subaction   The subaction to apply haptics to, which must
         *                    have been specified to Action::addSubaction().
         * @return true on success, false otherwise.
         */
        bool stopHapticFeedback(Subaction *subaction = nullptr);
};

}

#endif