//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $NoKeywords: $
//=============================================================================//

#ifndef ROPE_PHYSICS_H
#define ROPE_PHYSICS_H
#ifdef _WIN32
#pragma once
#endif

#include "networkvar.h"
#include "simple_physics.h"

class CRopeSpring {
   public:
    Vector *m_pNode1;
    Vector *m_pNode2;
};

class CBaseRopePhysics : public CSimplePhysics::IHelper {
   public:
    DECLARE_CLASS_NOBASE(CBaseRopePhysics);

    CBaseRopePhysics(CSimplePhysics::CNode *pNodes, int nNodes,
                     CRopeSpring *pSprings, float *flSpringDistsSqr);

    // nNodes should be less than or equal to what you passed into the
    // constructor.
    void SetNumNodes(int nNodes);

    // Restart timers and such.
    void Restart();

    void ResetSpringLength(float flSpringDist);
    float GetSpringLength() const;
    void ResetNodeSpringLength(int iStartNode, float flSpringDist);

    // Set simulation parameters.
    // If you pass in a delegate, you can be called to apply constraints.
    void SetupSimulation(float flSpringDist,
                         CSimplePhysics::IHelper *pDelegate = 0);

    // Set the physics delegate.
    void SetDelegate(CSimplePhysics::IHelper *pDelegate);

    void Simulate(float dt);

    int NumNodes() { return m_nNodes; }
    CSimplePhysics::CNode *GetNode(int iNode) { return &m_pNodes[iNode]; }
    CSimplePhysics::CNode *GetFirstNode() { return &m_pNodes[0]; }
    CSimplePhysics::CNode *GetLastNode() { return &m_pNodes[m_nNodes - 1]; }

   public:
    virtual void GetNodeForces(CSimplePhysics::CNode *pNodes, int iNode,
                               Vector *pAccel);
    virtual void ApplyConstraints(CSimplePhysics::CNode *pNodes, int nNodes);

   private:
    int NumSprings() { return m_nNodes - 1; }

   protected:
    CSimplePhysics::IHelper *m_pDelegate;

    CSimplePhysics::CNode *m_pNodes;
    int m_nNodes;

    CRopeSpring *m_pSprings;

    float m_flSpringDist;
    float m_flSpringDistSqr;

    // Spring lengths per node
    float *m_flNodeSpringDistsSqr;

    CSimplePhysics m_Physics;
};

template <int NUM_NODES>
class CRopePhysics : public CBaseRopePhysics {
   public:
    CRopePhysics();

    CSimplePhysics::CNode m_Nodes[NUM_NODES];
    CRopeSpring m_Springs[NUM_NODES - 1];
    float m_SpringDistsSqr[NUM_NODES - 1];
};

template <int NUM_NODES>
CRopePhysics<NUM_NODES>::CRopePhysics()
    : CBaseRopePhysics(m_Nodes, NUM_NODES, m_Springs, m_SpringDistsSqr) {}

#endif  // ROPE_PHYSICS_H