/*
   orxonox - the future of 3D-vertical-scrollers

   Copyright (C) 2004 orx

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   ### File Specific:
   main-programmer: Benjamin Grauer
   co-programmer: ...
*/

/*!
    \file t_animation.h
*/

#ifndef _T_ANIMATION_H
#define _T_ANIMATION_H

#include "animation.h"

#define DELTA_X 0.05  //!< the percentag of the distance that doesnt have to be done by neg_exp (asymptotical) ~ maschinendelta

//! A Struct for Keyframes that simply hold a float
typedef struct KeyFrameF
{
  float duration;             //!< duration of this keyframe
  float value;                //!< value of this keyframe
  ANIM_FUNCTION animFunc;     //!< with whitch function to iterate to the next KeyFrameF
};


//! A Class to handle some animation for single floated values.
template<class T> class tAnimation : public Animation
{
 public:
  tAnimation(T* object = NULL, void (T::*funcToAnim)(float) = NULL);
  virtual ~tAnimation();

  void setFuncToAnim(T* object, void (T::*funcToAnim)(float));

  void addKeyFrame(float value, float duration, ANIM_FUNCTION animFunc = ANIM_DEFAULT_FUNCTION);

  virtual void rewind();
  virtual void tick(float dt);

 private:
  // animation functions
  void setAnimFunc(ANIM_FUNCTION animFunc);
  float constant(float timePassed) const;
  float linear(float timePassed) const;
  float sine(float timePassed) const;
  float cosine(float timePassed) const;
  float exp(float timePassed) const;
  float negExp(float timePassed) const;
  float quadratic(float timePassed) const;
  float random(float timePassed) const;


  //  ANIM_FUNCTION animFunc
  float (tAnimation<T>::*animFunc)(float) const;  //!< A Function for the AnimationType

  KeyFrameF* currentKeyFrame;                     //!< The current KeyFrame
  KeyFrameF* nextKeyFrame;                        //!< The KeyFrame we iterate to
  tList<KeyFrameF>* keyFrameList;                 //!< The KeyFrameList

  T* object;                                      //!< The Object from which to Animate something
  void (T::*funcToAnim)(float);                   //!< The function to Animate

  float expFactor;                                //!< some factors
};



/**
 *  standard constructor
*/
template<class T>
tAnimation<T>::tAnimation (T* object, void (T::*funcToAnim)(float))
{
  // create a new List
  this->keyFrameList = new tList<KeyFrameF>();
  KeyFrameF* tmpKeyFrame = new KeyFrameF;
  tmpKeyFrame->value = 0.0;
  tmpKeyFrame->duration = 1.0;
  keyFrameList->add(tmpKeyFrame);

  this->currentKeyFrame = tmpKeyFrame;
  this->nextKeyFrame = tmpKeyFrame;

  this->animFunc = &tAnimation<T>::linear;

  this->setFuncToAnim(object, funcToAnim);
}


/**
 *  standard deconstructor

   deletes all the Keyframes
*/
template<class T>
tAnimation<T>::~tAnimation ()
{
  // delete all the KeyFrames
  tIterator<KeyFrameF>* itKF = keyFrameList->getIterator();
  KeyFrameF*  enumKF = itKF->nextElement();
  while (enumKF)
    {
      delete enumKF;
      enumKF = itKF->nextElement();
    }
  delete itKF;
  delete this->keyFrameList;
}

/**
 *  rewinds the Animation to the beginning (first KeyFrame and time == 0)
*/
template<class T>
void tAnimation<T>::rewind()
{
  this->currentKeyFrame = keyFrameList->firstElement();
  this->nextKeyFrame = keyFrameList->nextElement(keyFrameList->firstElement());
  this->localTime = 0.0;
  this->setAnimFunc(this->currentKeyFrame->animFunc);
}

/**
 *  sets the Function we want to animate
 * @param object from what object do we want to animate
 * @param funcToAnim which function
*/
template<class T>
void tAnimation<T>::setFuncToAnim(T* object, void (T::*funcToAnim)(float))
{
  this->baseObject = this->object = object;
  this->funcToAnim = funcToAnim;
}

/**
 *  Appends a new Keyframe
 * @param value the value of the new KeyFrame
 * @param duration The duration from the new KeyFrame to the next one
 * @param animFunc The function to animate between this keyFrame and the next one
*/
template<class T>
void tAnimation<T>::addKeyFrame(float value, float duration, ANIM_FUNCTION animFunc)
{
  // some small check
  if (duration <= 0.0)
    duration = 1.0;
  if (animFunc == ANIM_NULL)
    animFunc = ANIM_DEFAULT_FUNCTION;

  KeyFrameF* tmpKeyFrame;

  // when adding the first frame
  if (this->keyFrameCount == 0)
    {
      tmpKeyFrame = this->keyFrameList->firstElement();
      this->setAnimFunc(animFunc);
    }
  else
    {
      tmpKeyFrame = new KeyFrameF;
      // when adding the second frame
      if (this->currentKeyFrame == this->nextKeyFrame)
        this->nextKeyFrame = tmpKeyFrame;
      this->keyFrameList->add(tmpKeyFrame);
    }

  tmpKeyFrame->value = value;
  tmpKeyFrame->duration = duration;
  tmpKeyFrame->animFunc = animFunc;
  this->keyFrameCount++;
}

/**
 *  ticks the Animation
 * @param dt how much time to tick
*/
template<class T>
void tAnimation<T>::tick(float dt)
{
  if (this->bRunning)
    {
      this->localTime += dt;
      if (localTime >= this->currentKeyFrame->duration)
        {
          if (likely(this->keyFramesToPlay != 0))
            {
              if (unlikely(this->keyFramesToPlay > 0))
                --this->keyFramesToPlay;
              // switching to the next Key-Frame
              this->localTime -= this->currentKeyFrame->duration;

              this->currentKeyFrame = this->nextKeyFrame;
              // checking, if we should still Play the animation
              if (this->currentKeyFrame == this->keyFrameList->lastElement())
                this->handleInfinity();
              this->nextKeyFrame = this->keyFrameList->nextElement(this->currentKeyFrame);

              //printf("%p from:%f to:%f\n", this->currentKeyFrame,this->currentKeyFrame->value, this->nextKeyFrame->value);
              this->setAnimFunc(this->currentKeyFrame->animFunc);
            }
          else
            this->pause();
        }

      (this->object->*(funcToAnim))((this->*animFunc)(this->localTime));
    }
}

/**
 *  Sets The kind of Animation between this keyframe and the next one
 * @param animFunc The Type of Animation to set
*/
template<class T>
void tAnimation<T>::setAnimFunc(ANIM_FUNCTION animFunc)
{
  switch (animFunc)
    {
    default:
    case ANIM_CONSTANT:
      this->animFunc = &tAnimation<T>::constant;
      break;
    case ANIM_LINEAR:
      this->animFunc = &tAnimation<T>::linear;
      break;
    case ANIM_SINE:
      this->animFunc = &tAnimation<T>::sine;
      break;
    case ANIM_COSINE:
      this->animFunc = &tAnimation<T>::cosine;
      break;
    case ANIM_EXP:
      this->animFunc = &tAnimation<T>::exp;
      break;
    case ANIM_NEG_EXP:
      {
        this->animFunc = &tAnimation<T>::negExp;
        expFactor =  - 1.0 / this->currentKeyFrame->duration * logf(DELTA_X);
        break;
      }
    case ANIM_QUADRATIC:
      this->animFunc = &tAnimation<T>::quadratic;
      break;
    case ANIM_RANDOM:
      this->animFunc = &tAnimation<T>::random;
      break;
    }
}


// animation functions
/**
 *  stays at the value of the currentKeyFrame
 * @param timePassed The time passed since this Keyframe began
*/
template<class T>
float tAnimation<T>::constant(float timePassed) const
{
  return this->currentKeyFrame->value;
}

/**
 *  linear interpolation between this keyframe and the next one
 * @param timePassed The time passed since this Keyframe began
*/
template<class T>
float tAnimation<T>::linear(float timePassed) const
{
  return this->currentKeyFrame->value + (this->nextKeyFrame->value - this->currentKeyFrame->value)
    * (timePassed / this->currentKeyFrame->duration);
}

/**
 *  a Sinusodial Interpolation between this keyframe and the next one
 * @param timePassed The time passed since this Keyframe began
*/
template<class T>
float tAnimation<T>::sine(float timePassed) const
{
  if (timePassed * 2.0 < this->currentKeyFrame->duration)
    return this->currentKeyFrame->value + (this->nextKeyFrame->value - this->currentKeyFrame->value)
      * sin( M_PI * timePassed / this->currentKeyFrame->duration)/2;
  else
    return this->nextKeyFrame->value - (this->nextKeyFrame->value - this->currentKeyFrame->value)
      * sin( M_PI * (1.0 - timePassed / this->currentKeyFrame->duration))/2;
  /*
  printf("::%f::::%f::\n",timePassed/this->currentKeyFrame->duration,retVal);
  return retVal;
  */
}

/**
 *  a cosine interpolation between this keyframe and the next one
 * @param timePassed The time passed since this Keyframe began
*/
template<class T>
float tAnimation<T>::cosine(float timePassed) const
{
  return ((this->nextKeyFrame->value + this->currentKeyFrame->value) +
    (this->currentKeyFrame->value - this->nextKeyFrame->value) *
    cos( M_PI * timePassed / this->currentKeyFrame->duration))/2;
}

/**
 *  an exponential interpolation between this keyframe and the next one
 * @param timePassed The time passed since this Keyframe began
*/
template<class T>
float tAnimation<T>::exp(float timePassed) const
{
  return this->linear(timePassed);

}

/**
 *  a negative exponential interpolation between this keyframe and the next one
 * @param timePassed The time passed since this Keyframe began
*/
template<class T>
float tAnimation<T>::negExp(float timePassed) const
{
  float d = this->currentKeyFrame->value - this->nextKeyFrame->value;
  float e = d * (1.0 - expf(- timePassed * expFactor));
  return  this->currentKeyFrame->value - e;
}

/**
 *  a quadratic interpolation between this keyframe and the next one
 * @param timePassed The time passed since this Keyframe began
*/
template<class T>
float tAnimation<T>::quadratic(float timePassed) const
{
  this->linear(timePassed);
}

/**
 *  some random animation (fluctuating)
 * @param timePassed The time passed since this Keyframe began
*/
template<class T>
float tAnimation<T>::random(float timePassed) const
{
  return this->currentKeyFrame->value +
    (this->nextKeyFrame->value - this->currentKeyFrame->value) *
    (float)rand()/(float)RAND_MAX;
}

#endif /* _T_ANIMATION_H */