#include "PID_v1.h"  
#include "LMotorController.h"
#include "I2Cdev.h"
#include "MPU6050_6Axis_MotionApps20.h"

#if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
 #include "Wire.h"
#endif

#define MIN_ABS_SPEED 30

MPU6050 mpu;

// MPU control/status vars
bool dmpReady = false; // set true if DMP init was successful
uint8_t mpuIntStatus; // holds actual interrupt status byte from MPU
uint8_t devStatus; // return status after each device operation (0 = success, !0 = error)
uint16_t packetSize; // expected DMP packet size (default is 42 bytes)
uint16_t fifoCount; // count of all bytes currently in FIFO
uint8_t fifoBuffer[64]; // FIFO storage buffer

// orientation/motion vars
Quaternion q; // [w, x, y, z] quaternion container
VectorFloat gravity; // [x, y, z] gravity vector
float ypr[3]; // [yaw, pitch, roll] yaw/pitch/roll container and gravity vector

//PID
double originalSetpoint = 180;      // angle of robot when it is standing
double setpoint = originalSetpoint;
double movingAngleOffset = 0.1;
double input, output;

//adjust these values to fit your own design
double Kp = 180;  
double Ki = 650; 
double Kd = 9;

PID pid(&input, &output, &setpoint, Kp, Ki, Kd, DIRECT);

double motorSpeedFactorLeft = 0.6;
double motorSpeedFactorRight = 0.5;

//MOTOR CONTROLLER
int ENA = 5;
int IN1 = 6;
int IN2 = 7;
int IN3 = 9;
int IN4 = 8;
int ENB = 10;
LMotorController motorController(ENA, IN1, IN2, ENB, IN3, IN4, motorSpeedFactorLeft, motorSpeedFactorRight);

volatile bool mpuInterrupt = false; // indicates whether MPU interrupt pin has gone high
void dmpDataReady()
{
 mpuInterrupt = true;
}


void setup()
{
 // join I2C bus (I2Cdev library doesn't do this automatically)
 #if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
 Wire.begin();
 TWBR = 24; // 400kHz I2C clock (200kHz if CPU is 8MHz)
 #elif I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_FASTWIRE
 Fastwire::setup(400, true);
 #endif
          
 Serial.begin(115200);

 mpu.initialize();

 devStatus = mpu.dmpInitialize();

 // supply your own gyro offsets here, scaled for min sensitivity
 mpu.setXGyroOffset(220);
 mpu.setYGyroOffset(76);
 mpu.setZGyroOffset(-85);
 mpu.setZAccelOffset(1788); // 1688 factory default for my test chip

 // make sure it worked (returns 0 if so)
 if (devStatus == 0)
 {
 // turn on the DMP, now that it's ready
 mpu.setDMPEnabled(true);

 // enable Arduino interrupt detection
 attachInterrupt(0, dmpDataReady, RISING);
 mpuIntStatus = mpu.getIntStatus();

 // set our DMP Ready flag so the main loop() function knows it's okay to use it
 dmpReady = true;

 // get expected DMP packet size for later comparison
 packetSize = mpu.dmpGetFIFOPacketSize();
 
 //setup PID
 pid.SetMode(AUTOMATIC);
 pid.SetSampleTime(10);
 pid.SetOutputLimits(-255, 255); 
 }
 else
 {
 // ERROR!
 // 1 = initial memory load failed
 // 2 = DMP configuration updates failed
 // (if it's going to break, usually the code will be 1)
 Serial.print(F("DMP Initialization failed (code "));
 Serial.print(devStatus);
 Serial.println(F(")"));
 }
}


void loop()
{
  //char cin;
  
  // if programming failed, don't try to do anything
  if (!dmpReady) return;

  // wait for MPU interrupt or extra packet(s) available
  while (!mpuInterrupt && fifoCount < packetSize)
  {
    //no mpu data - performing PID calculations and output to motors 
    //
    // insert your codes at here
    // 
    //
    
  }

  // reset interrupt flag and get INT_STATUS byte
  mpuInterrupt = false;
  mpuIntStatus = mpu.getIntStatus();

  // get current FIFO count
  fifoCount = mpu.getFIFOCount();

  // check for overflow (this should never happen unless our code is too inefficient)
  if ((mpuIntStatus & 0x10) || fifoCount == 1024)
  {
    // reset so we can continue cleanly
    mpu.resetFIFO();
    Serial.println(F("FIFO overflow!"));

    // otherwise, check for DMP data ready interrupt (this should happen frequently)
  }
  else if (mpuIntStatus & 0x02)
  {
    // wait for correct available data length, should be a VERY short wait
    while (fifoCount < packetSize) fifoCount = mpu.getFIFOCount();

    // read a packet from FIFO
    mpu.getFIFOBytes(fifoBuffer, packetSize);
 
    // track FIFO count here in case there is > 1 packet available
    // (this lets us immediately read more without waiting for an interrupt)
    fifoCount -= packetSize;

    mpu.dmpGetQuaternion(&q, fifoBuffer);
    mpu.dmpGetGravity(&gravity, &q);
    mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);
    
    input = ypr[1] * 180/M_PI + 180;      // tilt angle of robot
  }
}
