/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
 *                                                                                       *
 * Copyright (c) 2014-2016                                                               *
 *                                                                                       *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
 * software and associated documentation files (the "Software"), to deal in the Software *
 * without restriction, including without limitation the rights to use, copy, modify,    *
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 * permit persons to whom the Software is furnished to do so, subject to the following   *
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 * The above copyright notice and this permission notice shall be included in all copies *
 * or substantial portions of the Software.                                              *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   *
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         *
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 * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                                         *
 ****************************************************************************************/

#ifndef __OPENSPACE_CORE___INTERACTIONMODE___H__
#define __OPENSPACE_CORE___INTERACTIONMODE___H__

#include <openspace/interaction/keyboardcontroller.h>
#include <openspace/network/parallelconnection.h>
#include <openspace/util/mouse.h>
#include <openspace/util/keys.h>

#ifdef OPENSPACE_MODULE_GLOBEBROWSING_ENABLED
#include <modules/globebrowsing/tile/tileindex.h>
#include <modules/globebrowsing/geometry/geodetic2.h>
#endif

#include <list>

namespace openspace {

class Camera;
class SceneGraphNode;

namespace globebrowsing {
    class RenderableGlobe;
}

namespace interaction {

    template <typename T>
    class Interpolator
    {
    public:
        Interpolator(std::function<T(double)> transferFunction)
        : _t(0.0)
        , _transferFunction(transferFunction) {};
        ~Interpolator() {};

        void start() { _t = 0.0; };
        void end() { _t = 1.0; };
        void step(double delta) { _t += delta; };

        T value() { return _transferFunction(_t); };
        bool isInterpolating() { return _t < 1.0; };
    private:
        std::function<T(double)> _transferFunction;
        double _t;
    };

    class InputState
    {
    public:
        InputState();
        ~InputState();

        // Callback functions
        void keyboardCallback(Key key, KeyModifier modifier, KeyAction action);
        void mouseButtonCallback(MouseButton button, MouseAction action);
        void mousePositionCallback(double mouseX, double mouseY);
        void mouseScrollWheelCallback(double mouseScrollDelta);

        // Mutators
        void addKeyframe(const datamessagestructures::CameraKeyframe &kf);
        void clearKeyframes();
        void clearOldKeyframes();

        // Accessors
        const std::list<std::pair<Key, KeyModifier> >& getPressedKeys() const;
        const std::list<MouseButton>& getPressedMouseButtons() const;
        glm::dvec2 getMousePosition() const;
        double getMouseScrollDelta() const;
        const std::vector<datamessagestructures::CameraKeyframe>& keyframes() const;

        bool isKeyPressed(std::pair<Key, KeyModifier> keyModPair) const;
        bool isKeyPressed(Key key) const;
        bool isMouseButtonPressed(MouseButton mouseButton) const;
    private:
        // Input from keyboard and mouse
        std::list<std::pair<Key, KeyModifier> > _keysDown;
        std::list<MouseButton> _mouseButtonsDown;
        glm::dvec2 _mousePosition;
        double _mouseScrollDelta;

        // Remote input via keyframes
        std::vector<datamessagestructures::CameraKeyframe> _keyframes;
    };



class InteractionMode
{
public:
    InteractionMode();
    ~InteractionMode();

    // Mutators
    virtual void setFocusNode(SceneGraphNode* focusNode);

    // Accessors
    SceneGraphNode* focusNode();
    Interpolator<double>& rotateToFocusNodeInterpolator();
    
    virtual void updateMouseStatesFromInput(const InputState& inputState, double deltaTime) = 0;
    virtual void updateCameraStateFromMouseStates(Camera& camera, double deltaTime) = 0;

protected:
    /**
        Inner class that acts as a smoothing filter to a variable. The filter has a step
        response on a form that resembles the function y = 1-e^(-t/scale). The variable
        will be updates as soon as it is set to a value (calling the set() function).
    */
    template <typename T, typename ScaleType>
    class DelayedVariable {
    public:
        DelayedVariable(ScaleType scaleFactor, ScaleType friction) {
            _scaleFactor = scaleFactor;
            _friction = glm::max(friction, ScaleType(0.0));
        }
        void set(T value, double dt) {
            _targetValue = value;
            _currentValue = _currentValue + (_targetValue - _currentValue) *
                std::min(_scaleFactor * dt, 1.0); // less or equal to 1.0 keeps it stable
        }
        void decelerate(double dt) {
            _currentValue = _currentValue + (- _currentValue) *
                std::min(_scaleFactor * _friction * dt, 1.0); // less or equal to 1.0 keeps it stable
        }
        void setHard(T value) {
            _targetValue = value;
            _currentValue = value;
        }
        void setFriction(ScaleType friction) {
            _friction = glm::max(friction, ScaleType(0.0));
        }
        void setScaleFactor(ScaleType scaleFactor) {
            _scaleFactor = scaleFactor;
        }
        T get() {
            return _currentValue;
        }
    private:
        ScaleType _scaleFactor;
        ScaleType _friction;
        T _targetValue;
        T _currentValue;
    };

    struct MouseState {
        MouseState(double scaleFactor)
            : velocity(scaleFactor, 1)
            , previousPosition(0.0, 0.0) {}
        void setFriction(double friction) {
            velocity.setFriction(friction);
        }
        void setVelocityScaleFactor(double scaleFactor) {
            velocity.setScaleFactor(scaleFactor);
        }
        glm::dvec2 previousPosition;
        DelayedVariable<glm::dvec2, double> velocity;
    };

    SceneGraphNode* _focusNode = nullptr;
    glm::dvec3 _previousFocusNodePosition;
    glm::dquat _previousFocusNodeRotation;
    
    
    Interpolator<double> _rotateToFocusNodeInterpolator;
};

class KeyframeInteractionMode : public InteractionMode
{
public:
    KeyframeInteractionMode();
    ~KeyframeInteractionMode();

    virtual void updateMouseStatesFromInput(const InputState& inputState, double deltaTime);
    virtual void updateCameraStateFromMouseStates(Camera& camera, double deltaTime);

private:
    std::vector<datamessagestructures::CameraKeyframe> _keyframes;
    double _currentKeyframeTime;
};

class GlobeBrowsingInteractionMode;

class OrbitalInteractionMode : public InteractionMode
{
public:
    class MouseStates
    {
    public:
        /**
        \param sensitivity
        \param velocityScaleFactor can be set to 60 to remove the inertia of the
        interaction. Lower value will make it harder to move the camera. 
        */
        MouseStates(double sensitivity, double velocityScaleFactor);
        void updateMouseStatesFromInput(const InputState& inputState, double deltaTime);
        void setRotationalFriction(double friction);
        void setHorizontalFriction(double friction);
        void setVerticalFriction(double friction);
        void setSensitivity(double sensitivity);
        void setVelocityScaleFactor(double scaleFactor);

        glm::dvec2 synchedGlobalRotationMouseVelocity();
        glm::dvec2 synchedLocalRotationMouseVelocity();
        glm::dvec2 synchedTruckMovementMouseVelocity();
        glm::dvec2 synchedLocalRollMouseVelocity();
        glm::dvec2 synchedGlobalRollMouseVelocity();

    private:
        double _sensitivity;

        MouseState _globalRotationMouseState;
        MouseState _localRotationMouseState;
        MouseState _truckMovementMouseState;
        MouseState _localRollMouseState;
        MouseState _globalRollMouseState;
    };

    OrbitalInteractionMode(std::shared_ptr<MouseStates> mouseStates);
    ~OrbitalInteractionMode();

    //virtual void update(Camera& camera, const InputState& inputState, double deltaTime);

    virtual void updateMouseStatesFromInput(const InputState& inputState, double deltaTime);
    virtual void updateCameraStateFromMouseStates(Camera& camera, double deltaTime);

protected:
    //void updateCameraStateFromMouseStates(Camera& camera, double deltaTime);
    std::shared_ptr<MouseStates> _mouseStates;
};

class GlobeBrowsingInteractionMode : public OrbitalInteractionMode
{
public:
    GlobeBrowsingInteractionMode(std::shared_ptr<MouseStates> mouseStates);
    ~GlobeBrowsingInteractionMode();

    virtual void setFocusNode(SceneGraphNode* focusNode);
    //virtual void update(Camera& camera, const InputState& inputState, double deltaTime);
    virtual void updateCameraStateFromMouseStates(Camera& camera, double deltaTime);
#ifdef OPENSPACE_MODULE_GLOBEBROWSING_ENABLED
    void goToChunk(Camera& camera, globebrowsing::TileIndex ti, glm::vec2 uv,
                   bool resetCameraDirection);
    void goToGeodetic2(Camera& camera, globebrowsing::Geodetic2 geo2,
                   bool resetCameraDirection);
    
    void goToGeodetic3(Camera& camera,  globebrowsing::Geodetic3 geo3);
    void resetCameraDirection(Camera& camera,  globebrowsing::Geodetic2 geo2);
#endif
private:
    //void updateCameraStateFromMouseStates(Camera& camera, double deltaTime);
#ifdef OPENSPACE_MODULE_GLOBEBROWSING_ENABLED
    globebrowsing::RenderableGlobe* _globe;
#endif
};

} // namespace interaction
} // namespace openspace

#endif // __OPENSPACE_CORE___INTERACTIONMODE___H__