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/************************************************************************/
/* Flight Attitude                                                      */
/************************************************************************/

#include <stdlib.h>
#include <avr/io.h>

#include "attitude.h"
#include "dongfangMath.h"

// where our main data flow comes from.
#include "analog.h"

#include "configuration.h"

// Some calculations are performed depending on some stick related things.
#include "controlMixer.h"

// For Servo_On / Off
// #include "timer2.h"

#ifdef USE_MK3MAG
#include "mk3mag.h"
#include "gps.h"
#endif
#define CHECK_MIN_MAX(value, min, max) {if(value < min) value = min; else if(value > max) value = max;}

/*
 * Gyro readings, as read from the analog module. It would have been nice to flow
 * them around between the different calculations as a struct or array (doing
 * things functionally without side effects) but this is shorter and probably
 * faster too.
 * The variables are overwritten at each attitude calculation invocation - the values
 * are not preserved or reused.
 */
int16_t pitchRate, rollRate, yawRate;

// With different (less) filtering
int16_t pitchRate_PID, rollRate_PID;
int16_t pitchDifferential, rollDifferential;

/*
 * Gyro readings, after performing "axis coupling" - that is, the transfomation
 * of rotation rates from the airframe-local coordinate system to a ground-fixed
 * coordinate system. If axis copling is disabled, the gyro readings will be
 * copied into these directly.
 * These are global for the same pragmatic reason as with the gyro readings.
 * The variables are overwritten at each attitude calculation invocation - the values
 * are not preserved or reused.
 */
int16_t ACPitchRate, ACRollRate, ACYawRate;

/*
 * Gyro integrals. These are the rotation angles of the airframe compared to the
 * horizontal plane, yaw relative to yaw at start.
 */
int32_t pitchAngle, rollAngle, yawAngle;

int readingHeight = 0;

// compass course
int16_t compassHeading = -1; // negative angle indicates invalid data.
int16_t compassCourse = -1;
int16_t compassOffCourse = 0;
uint16_t updateCompassCourse = 0;
uint8_t compassCalState = 0;

// uint8_t FunnelCourse = 0;
uint16_t badCompassHeading = 500;
int32_t yawGyroHeading; // Yaw Gyro Integral supported by compass

int32_t turnOver180 = GYRO_DEG_FACTOR_PITCHROLL * 180L;
int32_t turnOver360 = GYRO_DEG_FACTOR_PITCHROLL * 360L;

int32_t pitchCorrectionSum = 0, rollCorrectionSum = 0;

/*
 * Experiment: Compensating for dynamic-induced gyro biasing.
 */
int16_t dynamicOffsetPitch = 0, dynamicOffsetRoll = 0, dynamicOffsetYaw = 0;
// int16_t savedDynamicOffsetPitch = 0, savedDynamicOffsetRoll = 0;
// int32_t dynamicCalPitch, dynamicCalRoll, dynamicCalYaw;
// int16_t dynamicCalCount;

/************************************************************************
 * Set inclination angles from the acc. sensor data.                    
 * If acc. sensors are not used, set to zero.                          
 * TODO: One could use inverse sine to calculate the angles more        
 * accurately, but sinc: 1) the angles are rather at times when it      
 * makes sense to set the integrals (standing on ground, or flying at  
 * constant speed, and 2) at small angles a, sin(a) ~= constant * a,    
 * it is hardly worth the trouble.                                      
 ************************************************************************/

int32_t getPitchAngleEstimateFromAcc(void) {
  return GYRO_ACC_FACTOR * (int32_t)filteredPitchAxisAcc;
}

int32_t getRollAngleEstimateFromAcc(void) {
  return GYRO_ACC_FACTOR * (int32_t)filteredRollAxisAcc;
}

void setStaticAttitudeAngles(void) {
#ifdef ATTITUDE_USE_ACC_SENSORS
  pitchAngle = getPitchAngleEstimateFromAcc();
  rollAngle = getRollAngleEstimateFromAcc();
#else
  pitchAngle = 0;
  rollAngle = 0;
#endif
}

/************************************************************************
 * Neutral Readings                                                    
 ************************************************************************/
void attitude_setNeutral(void) {
  // Servo_Off(); // disable servo output. TODO: Why bother? The servos are going to make a jerk anyway.
  dynamicParams.AxisCoupling1 = dynamicParams.AxisCoupling2 = 0;

  dynamicOffsetPitch = dynamicOffsetRoll = 0;
 
  // Calibrate hardware.
  analog_calibrate();

  // reset gyro readings
  pitchRate = rollRate = yawRate = 0;

  // reset gyro integrals to acc guessing
  setStaticAttitudeAngles();
  yawAngle = 0;

  // update compass course to current heading
  compassCourse = compassHeading;
  // Inititialize YawGyroIntegral value with current compass heading
  yawGyroHeading = (int32_t)compassHeading * GYRO_DEG_FACTOR_YAW;

  // Servo_On(); //enable servo output
}

/************************************************************************
 * Get sensor data from the analog module, and release the ADC          
 * TODO: Ultimately, the analog module could do this (instead of dumping
 * the values into variables).                                          
 *************************************************************************/
void getAnalogData(void) {
  // For the differential calculation. Diff. is not supported right now.
  // int16_t d2Pitch, d2Roll;
  pitchRate_PID = (hiResPitchGyro + dynamicOffsetPitch) / HIRES_GYRO_INTEGRATION_FACTOR;
  pitchRate = (filteredHiResPitchGyro + dynamicOffsetPitch) / HIRES_GYRO_INTEGRATION_FACTOR;
  pitchDifferential = pitchGyroD;

  rollRate_PID = (hiResRollGyro + dynamicOffsetRoll) / HIRES_GYRO_INTEGRATION_FACTOR;
  rollRate = (filteredHiResRollGyro + dynamicOffsetRoll) / HIRES_GYRO_INTEGRATION_FACTOR;
  rollDifferential = rollGyroD;

  yawRate = yawGyro + dynamicOffsetYaw;

  // We are done reading variables from the analog module. Interrupt-driven sensor reading may restart.
  // TODO: Is that not a little early to measure for next control invocation?
  analogDataReady = 0;
  analog_start();
}

/************************************************************************
 * Axis coupling, H&I Style                                            
 * Currently not working (and there is a bug in it,
 * which causes unstable flight in heading-hold mode).
 ************************************************************************/
void H_and_I_axisCoupling(void) {
  int32_t tmpl = 0, tmpl2 = 0, tmp13 = 0, tmp14 = 0;
  int16_t CouplingNickRoll = 0, CouplingRollNick = 0;

  tmp13 = (rollRate * pitchAngle) / 2048L;
  tmp13 *= dynamicParams.AxisCoupling2; // 65
  tmp13 /= 4096L;
  CouplingNickRoll = tmp13;
 
  tmp14 = (pitchRate * rollAngle) / 2048L;
  tmp14 *= dynamicParams.AxisCoupling2; // 65
  tmp14 /= 4096L;
  CouplingRollNick = tmp14;
 
  tmp14 -= tmp13;

  ACYawRate = yawRate + tmp14;
 
  /*
  if(!dynamicParams.AxisCouplingYawCorrection) ACYawRate = yawRate - tmp14 / 2; // force yaw
  else ACYawRate
  */
 
  tmpl = ((yawRate + tmp14) * pitchAngle) / 2048L;
  tmpl *= dynamicParams.AxisCoupling1;
  tmpl /= 4096L;
 
  tmpl2 = ((yawRate + tmp14) * rollAngle) / 2048L;
  tmpl2 *= dynamicParams.AxisCoupling1;
  tmpl2 /= 4096L;

  // if(abs(yawRate > 64)) {
  // if(labs(tmpl) > 128 || labs(tmpl2) > 128) FunnelCourse = 1;
  // }
 
  ACPitchRate = pitchRate - tmpl2 + tmpl / 100L;
  ACRollRate = rollRate + tmpl - tmpl2 / 100L;
}

/*
 * This is the standard flight-style coordinate system transformation
 * (from airframe-local axes to a ground-based system). For some reason
 * the MK uses a left-hand coordinate system. The tranformation has been
 * changed accordingly.
 */
void trigAxisCoupling(void) {
  int16_t cospitch = int_cos(pitchAngle);
  int16_t cosroll =  int_cos(rollAngle);
  int16_t sinroll =  int_sin(rollAngle);
  int16_t tanpitch = int_tan(pitchAngle);
#define ANTIOVF 1024
  ACPitchRate =            ((int32_t)pitchRate * cosroll              + (int32_t)yawRate * sinroll)                       /  (int32_t)MATH_UNIT_FACTOR;
  ACRollRate = rollRate + (((int32_t)pitchRate * sinroll / ANTIOVF * tanpitch  - (int32_t)yawRate * int_cos(rollAngle) / ANTIOVF * tanpitch) / ((int32_t)MATH_UNIT_FACTOR / ANTIOVF * MATH_UNIT_FACTOR));
  ACYawRate =             (-(int32_t)pitchRate * sinroll) / cospitch + ((int32_t)yawRate * cosroll) / cospitch;
}

void integrate(void) {
  // First, perform axis coupling. If disabled xxxRate is just copied to ACxxxRate.
  if(!looping && (staticParams.GlobalConfig & CFG_AXIS_COUPLING_ACTIVE)) {
    // The rotary rate limiter bit is abused for selecting axis coupling algorithm instead.
    if (staticParams.GlobalConfig & CFG_ROTARY_RATE_LIMITER)
      trigAxisCoupling();    
    else
      H_and_I_axisCoupling();
  } else {
    ACPitchRate = pitchRate;
    ACRollRate = rollRate;
    ACYawRate = yawRate;
  }

  DebugOut.Analog[3] = pitchRate;
  DebugOut.Analog[3 + 3] = ACPitchRate;
  DebugOut.Analog[4] = rollRate;
  DebugOut.Analog[4 + 3] = ACRollRate;
  DebugOut.Analog[5] = yawRate;
  DebugOut.Analog[5 + 3] = ACYawRate;

  /*
  DebugOut.Analog[9] = int_cos(pitchAngle);
  DebugOut.Analog[10] = int_sin(pitchAngle);
  DebugOut.Analog[11] = int_tan(pitchAngle);
  */

  /*
   * Yaw
   * Calculate yaw gyro integral (~ to rotation angle)
   * Limit yawGyroHeading proportional to 0 deg to 360 deg
   */
  yawGyroHeading += ACYawRate;
  yawAngle += ACYawRate;
  if(yawGyroHeading >= (360L * GYRO_DEG_FACTOR_YAW))    yawGyroHeading -= 360L * GYRO_DEG_FACTOR_YAW;  // 360 deg. wrap
  if(yawGyroHeading < 0)                                yawGyroHeading += 360L * GYRO_DEG_FACTOR_YAW;

  /*
   * Pitch axis integration and range boundary wrap.
   */
  pitchAngle += ACPitchRate;
  if(pitchAngle > turnOver180) {
    pitchAngle -= turnOver360;
  } else if (pitchAngle <= -turnOver180) {
    pitchAngle += turnOver360;
  }
 
  /*
   * Pitch axis integration and range boundary wrap.
   */
  rollAngle  += ACRollRate;
  if(rollAngle > turnOver180) {
    rollAngle -= turnOver360;
  } else if (rollAngle <= -turnOver180) {
    rollAngle += turnOver360;
  }
}

/************************************************************************
 * A kind of 0'th order integral correction, that corrects the integrals
 * directly. This is the "gyroAccFactor" stuff in the original code.
 * There is (there) also what I would call a  "minus 1st order correction"
 * - it corrects the differential of the integral = the gyro offsets.
 * That should only be necessary with drifty gyros like ENC-03.
 ************************************************************************/
void correctIntegralsByAcc0thOrder(void) {
  // TODO: Consider changing this to: Only correct when integrals are less than ...., or only correct when angular velocities
  // are less than ....., or reintroduce Kalman.
  // Well actually the Z axis acc. check is not so silly.
  if(!looping && //((ZAxisAcc >= -4) || (MKFlags & MKFLAG_MOTOR_RUN))) { // if not looping in any direction
     ZAxisAcc >= -dynamicParams.UserParams[7] && ZAxisAcc <= dynamicParams.UserParams[7]) {
    DebugOut.Digital[0] = 1;
   
    uint8_t permilleAcc = staticParams.GyroAccFactor; // NOTE!!! The meaning of this value has changed!!
    uint8_t debugFullWeight = 1;
   
    int32_t accDerivedPitch = getPitchAngleEstimateFromAcc();
    int32_t accDerivedRoll = getRollAngleEstimateFromAcc();
   
    if((maxControlPitch > 64) || (maxControlRoll > 64)) { // reduce effect during stick commands
      permilleAcc /= 2;
      debugFullWeight = 0;
    }
   
    if(abs(controlYaw) > 25) { // reduce further if yaw stick is active
      permilleAcc /= 2;
      debugFullWeight = 0;
    }

    /*
     * Add to each sum: The amount by which the angle is changed just below.
     */
    pitchCorrectionSum += permilleAcc * (accDerivedPitch - pitchAngle);
    rollCorrectionSum += permilleAcc * (accDerivedRoll - rollAngle);
   
    // There should not be a risk of overflow here, since the integrals do not exceed a few 100000.
    pitchAngle = ((int32_t)(1000 - permilleAcc) * pitchAngle + (int32_t)permilleAcc * accDerivedPitch) / 1000L;
    rollAngle = ((int32_t)(1000 - permilleAcc) * rollAngle + (int32_t)permilleAcc * accDerivedRoll) / 1000L;
   
    DebugOut.Digital[1] = debugFullWeight;
  } else {
    DebugOut.Digital[0] = 0;
  }
}

/************************************************************************
 * This is an attempt to correct not the error in the angle integrals
 * (that happens in correctIntegralsByAcc0thOrder above) but rather the
 * cause of it: Gyro drift, vibration and rounding errors.
 * All the corrections made in correctIntegralsByAcc0thOrder over
 * MINUSFIRSTORDERCORRECTION_TIME cycles are summed up. This number is
 * then divided by MINUSFIRSTORDERCORRECTION_TIME to get the approx.
 * correction that should have been applied to each iteration to fix
 * the error. This is then added to the dynamic offsets.
 ************************************************************************/
// 2 times / sec.
#define DRIFTCORRECTION_TIME 488/2
void driftCompensation(void) {
  static int16_t timer = DRIFTCORRECTION_TIME;
  int16_t deltaCompensation;
  if (! --timer) {
    timer = DRIFTCORRECTION_TIME;
    deltaCompensation = ((pitchCorrectionSum + 1000L * DRIFTCORRECTION_TIME / 2) / 1000 / DRIFTCORRECTION_TIME);
    CHECK_MIN_MAX(deltaCompensation, -staticParams.DriftComp, staticParams.DriftComp);
    dynamicOffsetPitch += deltaCompensation / staticParams.GyroAccTrim;

    deltaCompensation = ((rollCorrectionSum + 1000L * DRIFTCORRECTION_TIME / 2) / 1000 / DRIFTCORRECTION_TIME);
    CHECK_MIN_MAX(deltaCompensation, -staticParams.DriftComp, staticParams.DriftComp);
    dynamicOffsetRoll += deltaCompensation / staticParams.GyroAccTrim;

    pitchCorrectionSum = rollCorrectionSum = 0;

    DebugOut.Analog[28] = dynamicOffsetPitch;
    DebugOut.Analog[29] = dynamicOffsetRoll;
  }
}

/************************************************************************
 * Main procedure.
 ************************************************************************/
void calculateFlightAttitude(void) {  
  getAnalogData();
  integrate();
#ifdef ATTITUDE_USE_ACC_SENSORS
  correctIntegralsByAcc0thOrder();
  driftCompensation();
#endif
}

/*
void updateCompass(void) {
  int16_t w, v, r,correction, error;
 
  if(compassCalState && !(MKFlags & MKFLAG_MOTOR_RUN)) {
    setCompassCalState();
  } else {
    // get maximum attitude angle
    w = abs(pitchAngle / 512);
    v = abs(rollAngle / 512);
    if(v > w) w = v;
    correction = w / 8 + 1;
    // calculate the deviation of the yaw gyro heading and the compass heading
    if (compassHeading < 0) error = 0; // disable yaw drift compensation if compass heading is undefined
    else error = ((540 + compassHeading - (yawGyroHeading / GYRO_DEG_FACTOR_YAW)) % 360) - 180;
    if(abs(yawRate) > 128) { // spinning fast
      error = 0;
    }
    if(!badCompassHeading && w < 25) {
      if(updateCompassCourse) {
        beep(200);
        yawGyroHeading = (int32_t)compassHeading * GYRO_DEG_FACTOR_YAW;
        compassCourse = (int16_t)(yawGyroHeading / GYRO_DEG_FACTOR_YAW);
        updateCompassCourse = 0;
      }
    }
    yawGyroHeading += (error * 8) / correction;
    w = (w * dynamicParams.CompassYawEffect) / 32;
    w = dynamicParams.CompassYawEffect - w;
    if(w >= 0) {
      if(!badCompassHeading) {
        v = 64 + (maxControlPitch + maxControlRoll) / 8;
        // calc course deviation
        r = ((540 + (yawGyroHeading / GYRO_DEG_FACTOR_YAW) - compassCourse) % 360) - 180;
        v = (r * w) / v; // align to compass course
        // limit yaw rate
        w = 3 * dynamicParams.CompassYawEffect;
        if (v > w) v = w;
        else if (v < -w) v = -w;
        yawAngle += v;
      }
      else
        { // wait a while
          badCompassHeading--;
        }
    }
    else {  // ignore compass at extreme attitudes for a while
      badCompassHeading = 500;
    }
  }
}
*/

/*
 * This is part of an experiment to measure average sensor offsets caused by motor vibration,
 * and to compensate them away. It brings about some improvement, but no miracles.
 * As long as the left stick is kept in the start-motors position, the dynamic compensation
 * will measure the effect of vibration, to use for later compensation. So, one should keep
 * the stick in the start-motors position for a few seconds, till all motors run (at the wrong
 * speed unfortunately... must find a better way)
 */
/*
void attitude_startDynamicCalibration(void) {
  dynamicCalPitch = dynamicCalRoll = dynamicCalYaw = dynamicCalCount = 0;
  savedDynamicOffsetPitch = savedDynamicOffsetRoll = 1000;
}

void attitude_continueDynamicCalibration(void) {
  // measure dynamic offset now...
  dynamicCalPitch += hiResPitchGyro;
  dynamicCalRoll += hiResRollGyro;
  dynamicCalYaw += rawYawGyroSum;
  dynamicCalCount++;
 
  // Param6: Manual mode. The offsets are taken from Param7 and Param8.
  if (dynamicParams.UserParam6 || 1) { // currently always enabled.
    // manual mode
    dynamicOffsetPitch = dynamicParams.UserParam7 - 128;
    dynamicOffsetRoll = dynamicParams.UserParam8 - 128;
  } else {
    // use the sampled value (does not seem to work so well....)
    dynamicOffsetPitch = savedDynamicOffsetPitch = -dynamicCalPitch / dynamicCalCount;
    dynamicOffsetRoll = savedDynamicOffsetRoll = -dynamicCalRoll / dynamicCalCount;
    dynamicOffsetYaw = -dynamicCalYaw / dynamicCalCount;
  }
 
  // keep resetting these meanwhile, to avoid accumulating errors.
  setStaticAttitudeIntegrals();
  yawAngle = 0;
}
*/