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#ifndef EXAMPLES_ATLASSIMBICON_CONTROLLER_HPP_
#define EXAMPLES_ATLASSIMBICON_CONTROLLER_HPP_

#include <vector>

#include <Eigen/Dense>
#include <dart/dart.hpp>

class StateMachine;

/// \brief Implementation of Simbicon (Simple biped locomotion control) for
/// Atlas robot
///
/// Reference: http://dl.acm.org/citation.cfm?id=1276509
class Controller
{
public:
  /// \brief Constructor
  Controller(
      dart::dynamics::SkeletonPtr _atlasRobot,
      dart::constraint::ConstraintSolver* _collisionSolver);

  /// \brief Destructor
  virtual ~Controller();

  /// \brief Called before every simulation time step in MyWindow class.
  /// Compute control force and apply it to Atlas robot
  virtual void update();

  /// \brief
  dart::dynamics::SkeletonPtr getAtlasRobot();

  /// \brief Get current state machine
  StateMachine* getCurrentState();

  /// \brief Change state to _stateMachine
  void changeStateMachine(StateMachine* _stateMachine, double _currentTime);

  /// \brief Change state machine to a state machine whose names is _name
  void changeStateMachine(const std::string& _name, double _currentTime);

  /// \brief Change state machine to a state machine whose index is _idx
  void changeStateMachine(std::size_t _idx, double _currentTime);

  /// \brief Get true iff this controller is currently allowing to control the
  /// Atlas robot
  bool isAllowingControl() const;

  /// \brief Keyboard control
  void keyboard(unsigned char _key, int _x, int _y, double _currentTime);

  /// \brief Print debug information
  void printDebugInfo() const;

  /// \brief Harness the robot
  void harnessPelvis();

  /// \brief Unharness the robot
  void unharnessPelvis();

  /// \brief Harness the robot
  void harnessLeftFoot();

  /// \brief Harness the robot
  void unharnessLeftFoot();

  /// \brief Harness the robot
  void harnessRightFoot();

  /// \brief Harness the robot
  void unharnessRightFoot();

  /// \brief Reset the robot
  void resetRobot();

  /// \brief Set the verbosity
  void setVerbosity(bool verbosity);

protected:
  /// \brief Atlas robot skeleton
  dart::dynamics::SkeletonPtr mAtlasRobot;

  /// \brief Conllision detector
  dart::constraint::ConstraintSolver* mConstratinSolver;

  /// \brief List of state machines
  std::vector<StateMachine*> mStateMachines;

  /// \brief Current state machine
  StateMachine* mCurrentStateMachine;

  /// \brief Flag for pelvis harnessing
  bool mPelvisHarnessOn;

  /// \brief Flag for left foot harnessing
  bool mLeftFootHarnessOn;

  /// \brief Flag for right foot harnessing
  bool mRightFootHarnessOn;

  /// \brief Index for coronal left hip
  std::size_t mCoronalLeftHip;

  /// \brief Index for coronal right hip
  std::size_t mCoronalRightHip;

  /// \brief Index for sagital left hip
  std::size_t mSagitalLeftHip;

  /// \brief Index for sagital right hip
  std::size_t mSagitalRightHip;

  /// \brief Lower bound for emergency stop
  double mMinPelvisHeight;

  /// \brief Upper bound for emergency stop
  double mMaxPelvisHeight;

private:
  /// \brief Check if this controller contains _stateMachine
  bool _containStateMachine(const StateMachine* _stateMachine) const;

  /// \brief Check if this controller contains a state machine whose name is
  ///        _name
  bool _containStateMachine(const std::string& _name) const;

  /// \brief Find a state machine whose name is _name
  StateMachine* _findStateMachine(const std::string& _name) const;

  /// \brief Build state machines
  void _buildStateMachines();

  /// \brief Create standing controller
  StateMachine* _createStandingStateMachine();

  /// \brief Create standing controller
  StateMachine* _createWalkingInPlaceStateMachine();

  /// \brief Create standing controller
  StateMachine* _createWalkingStateMachine();

  /// \brief Create running controller
  StateMachine* _createRunningStateMachine();

  /// \brief Set joint damping
  void _setJointDamping();

  /// \brief Get left foot
  dart::dynamics::BodyNode* _getLeftFoot() const;

  /// \brief Get right foot
  dart::dynamics::BodyNode* _getRightFoot() const;

  /// \brief Weld joint constraint for pelvis harnessing
  dart::constraint::WeldJointConstraintPtr mWeldJointConstraintPelvis;

  /// \brief Weld joint constraint for left foot harnessing
  dart::constraint::WeldJointConstraintPtr mWeldJointConstraintLeftFoot;

  /// \brief Weld joint constraint for right foot harnessing
  dart::constraint::WeldJointConstraintPtr mWeldJointConstraintRightFoot;

  /// \brief Initial state of the robot
  dart::dynamics::Skeleton::Configuration mInitialState;

  /// \brief Whether to print messages about the internal state
  bool mVerbosity;
};

#endif // EXAMPLES_ATLASSIMBICON_CONTROLLER_HPP_
