/// \file UtilityH.cpp
/// \brief General Math and Control utility functions
/// \author Hatem Darweesh
/// \date May 14, 2016

#include "op_utility/UtilityH.h"
#include <iostream>
#include <sstream>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <pwd.h>


using namespace std;


namespace UtilityHNS
{


UtilityH::UtilityH()
{
}

 UtilityH::~UtilityH()
{
}

 std::string UtilityH::GetHomeDirectory()
 {
  struct passwd *pw = getpwuid(getuid());
  const char *homedir = pw->pw_dir;
  return string(homedir);
 }

 double UtilityH::GetMomentumScaleFactor(const double& v)
 {
   if(v < 0.3)
     return 0.6;
   else if(v <6.4)
     return 0.3;
   else if(v < 20)
   {
     double m = 0.7/3.6;
     return m*(v - 6.4) + 0.3;
   }
   else
     return 0.9;
 }

 int UtilityH::GetSign(double x)
 {
   if(x < 0 )
     return -1;
   else
     return 1;
 }

 double UtilityH::FixNegativeAngle(const double& a)
{
  double angle = 0;
  if (a < -2.0 * M_PI || a >= 2.0 * M_PI) {
    angle = fmod(a, 2.0 * M_PI);
  } else {
    angle = a;
  }

  if(angle < 0) {
    angle = 2.0 * M_PI + angle;
  }

  return angle;
}

 double UtilityH::SplitPositiveAngle(const double& a)
{
  double angle = a;

  if (a < -2.0 * M_PI || a >= 2.0 * M_PI) {
    angle = fmod(a, 2.0 * M_PI);
  }

  if (angle >= M_PI) {
    angle -= 2.0 * M_PI;
  } else if (angle < -M_PI) {
    angle += 2.0 * M_PI;
  }
  
  return angle;
}

double UtilityH::InverseAngle(const double& a)
{

   double angle = 0;
   if(a < M_PI) {
     angle =  a + M_PI;
   } else {
     angle = a - M_PI;
   }
   
   return angle;
}

double UtilityH::AngleBetweenTwoAnglesPositive(const double& a1, const double& a2)
{
   double diff = a1 - a2;
   if(diff < 0)
     diff = a2 - a1;

   if(diff > M_PI)
     diff = 2.0*M_PI - diff;

   return diff;
}

double UtilityH::GetCircularAngle(const double& prevContAngle, const double& prevAngle, const double& currAngle)
{

  double diff = currAngle - prevAngle;
  if(diff > M_PI)
    diff = diff - 2.0*M_PI;
  if(diff < -M_PI)
    diff = diff + 2.0*M_PI;

  double c_ang = 0;
  if(prevContAngle == 0 || fabs(diff) < M_PI_2)
     c_ang = prevContAngle + diff;
  else
    c_ang = prevContAngle;

  return c_ang;
}

void UtilityH::GetTickCount(struct timespec& t)
{
  while(clock_gettime(0, & t) == -1);
}

double UtilityH::GetTimeDiff(const struct timespec& old_t,const struct timespec& curr_t)
{
  return (curr_t.tv_sec - old_t.tv_sec) + ((double)(curr_t.tv_nsec - old_t.tv_nsec)/ 1000000000.0);
}

double UtilityH::GetTimeDiffNow(const struct timespec& old_t)
{
  struct timespec curr_t;
  GetTickCount(curr_t);
  return (curr_t.tv_sec - old_t.tv_sec) + ((double)(curr_t.tv_nsec - old_t.tv_nsec)/ 1000000000.0);
}

string UtilityH::GetFilePrefixHourMinuteSeconds()
{
  struct timespec now_time;
  UtilityH::GetTickCount(now_time);
  tm *gmtm = localtime(&now_time.tv_sec);
  ostringstream str;

  str << "Y" << gmtm->tm_year;
  str << "-";
  str << "M" << gmtm->tm_mon;
  str << "-";
  str << "D" << gmtm->tm_mday;
  str << "-";
  str << "H" << gmtm->tm_hour;
  str << "-";
  str << "M" << gmtm->tm_min;
  str << "-";
  str << "S" << gmtm->tm_sec;

  return str.str();
}

string UtilityH::GetDateTimeStr()
{
  time_t now = time(0);
  char* dateStr = ctime(&now);
  string str(dateStr, strlen(dateStr)-1);
  int index = str.find(" ");
  while(index > 0)
  {
    str.replace(index,1, "_");
    index = str.find(" ");
  }

  index = str.find(":");
  while(index > 0)
  {
    str.replace(index,1, "-");
    index = str.find(":");
  }
  return str;
}

int  UtilityH::tsCompare (struct  timespec  time1,   struct  timespec  time2, int micro_tolerance)
{
  long nanoDiff =
    (time1.tv_sec * 1000000000 + time1.tv_nsec) - 
    (time2.tv_sec * 1000000000 + time2.tv_nsec);
  
  if (nanoDiff < -micro_tolerance) {
    return -1;  // time1 is less than time2
  } else if (nanoDiff > micro_tolerance) {
    return 1;  // time1 is greater than time2
  } else {
    return 0;  // time1 is equal to time2
  }
}

timespec UtilityH::GetTimeSpec(const time_t& srcT)
{
  timespec dstT;
  dstT.tv_sec = srcT/1000000000;
  dstT.tv_nsec = srcT - (dstT.tv_sec*1000000000);
  return dstT;
}

time_t UtilityH::GetLongTime(const struct timespec& srcT)
{
  time_t dstT;
  dstT = srcT.tv_sec * 1000000000 + srcT.tv_nsec;
  return dstT;
}

PIDController::PIDController()
{
  kp = kp_v = 0;
  ki = ki_v = 0;
  kd = kd_v = 0;
  pid_lim = pid_v = 0;
  upper_limit = lower_limit = 0;
  bEnableLimit= false;
  accumErr = 0;
  prevErr = 0;
  bResetD = false;
  bResetI = false;
}

PIDController::PIDController(const double& kp, const double& ki, const double& kd)
{
  Init(kp, ki, kd);
  upper_limit = lower_limit = 0;
  bEnableLimit= false;
  accumErr = 0;
  prevErr  = 0;
  bResetD = false;
  bResetI = false;

}

void PIDController::Setlimit(const double& upper,const double& lower)
{
  upper_limit = upper;
  lower_limit = lower;
  bEnableLimit = true;
}

double PIDController::getPID(const double& currValue, const double& targetValue)
{
  double e = targetValue - currValue;
  return getPID(e);
}

double PIDController::getPID(const double& e)
{
  //TODO Remember to add sampling time and multiply the time elapsed by the error
  //complex PID error calculation
  //TODO //De = ( e(i) + 3*e(i-1) - 3*e(i-2) - e(i-3) ) / 6


  if(bResetI)
  {
    bResetI = false;
    accumErr = 0;
  }

  if(bResetD)
  {
    bResetD = false;
    prevErr = e;
  }

  if(pid_v < upper_limit && pid_v > lower_limit)
    accumErr += e;

  double edot= e - prevErr;

  kp_v = kp * e;
  ki_v = ki *  accumErr;
  kd_v = kd * edot;

  pid_v = kp_v + ki_v + kd_v;
  pid_lim = pid_v;
  if(bEnableLimit)
  {
    if(pid_v > upper_limit)
    {
      pid_lim = upper_limit;
    }
    else if ( pid_v < lower_limit)
    {
      pid_lim = lower_limit;
    }
  }

  prevErr = e;

  return pid_lim;
}

std::string PIDController::ToStringHeader()
{
  std::ostringstream str_out;
  str_out << "Time" << "," <<"KP" << "," << "KI" << "," << "KD" << "," << "KP_v" << "," << "KI_v" << "," << "KD_v"
      << "," << "pid_v" << "," << "," << "pid_lim" << "," << "," << "prevErr" << "," << "accumErr" << "," ;
  return str_out.str();
}

std::string PIDController::ToString()
{
  std::ostringstream str_out;
  timespec t_stamp;
  UtilityH::GetTickCount(t_stamp);
  str_out << UtilityH::GetLongTime(t_stamp) << "," <<kp << "," << ki << "," << kd << "," << kp_v << "," << ki_v << "," << kd_v
        << "," << pid_v << "," << "," << pid_lim << "," << "," << prevErr << "," << accumErr << "," ;

  return str_out.str();

}

void PIDController::ResetD()
{
  bResetD = true;
}

void PIDController::ResetI()
{
  bResetI = true;
}

void PIDController::Init(const double& kp, const double& ki, const double& kd)
{
  this->kp = kp;
  this->ki = ki;
  this->kd = kd;
}

LowpassFilter::LowpassFilter()
{
  A = 0;
  d1 = 0;
  d2 = 0;
  w0 = 0;
  w1 = 0;
  w2 = 0;

  m = 0;
  sampleF = 0;
  cutOffF = 0;
}

LowpassFilter::~LowpassFilter()
{
//  if(A)
//    delete A;
//  if(d1)
//    delete d1;
//  if(d2)
//    delete d2;
//  if(w0)
//    delete w0;
//  if(w1)
//    delete w1;
//  if(w2)
//    delete w2;
}

LowpassFilter::LowpassFilter(const int& filterOrder, const double& sampleFreq, const double& cutOffFreq)
{
  Init(filterOrder, sampleFreq, cutOffFreq);
}

void LowpassFilter::Init(const int& n, const double& sampleFreq, const double& cutOffFreq)
{
  if(!(n == 2 || n == 4 || n == 6 || n == 8))
  {
    cout << "Undefined LowpassFilter order ! " << endl;

    A = 0;
    d1 = 0;
    d2 = 0;
    w0 = 0;
    w1 = 0;
    w2 = 0;

    m = 0;
    sampleF = 0;
    cutOffF = 0;
  }
  else
  {
    m = n/2;
    sampleF = sampleFreq;
    cutOffF = cutOffFreq;
    double ep = 1;
    double s = sampleFreq;
    double f = cutOffFreq;
    double a = tan(M_PI*f/s);
    double a2 = a*a;
    double u = log((1.0+sqrt(1.0+ep*ep))/ep);
    double su = sinh(u/(double)n);
    double cu = cosh(u/(double)n);
    double b, c;

//    A  = new double[m];
//    d1 = new double[m];
//    d2 = new double[m];
//    w0 = new double[m];
//    w1 = new double[m];
//    w2 = new double[m];
//
//    for(int i=0; i < m ; i++)
//    {
//      A[i]  = 0;
//      d1[i] = 0;
//      d2[i] = 0;
//      w0[i] = 0;
//      w1[i] = 0;
//      w2[i] = 0;
//    }

    for(int i=0; i< m; ++i)
    {
        b = sin(M_PI*(2.0*i+1.0)/(2.0*n))*su;
        c = cos(M_PI*(2.0*i+1.0)/(2.0*n))*cu;
        c = b*b + c*c;
        s = a2*c + 2.0*a*b + 1.0;
        A = a2/(4.0*s); // 4.0
        d1 = 2.0*(1-a2*c)/s;
        d2 = -(a2*c - 2.0*a*b + 1.0)/s;
    }
  }
}

double LowpassFilter::getFilter(const double& value)
{
  double ep = 2.3/1.0; // used to normalize
  double x = value;
  for(int i=0; i<m; ++i)
  {
    w0 = d1*w1 + d2*w2 + x;
    x = A*(w0 + 2.0*w1 + w2);
    w2 = w1;
    w1 = w0;
  }
  return ep*x;
}


}