// Red - 5V
// Black - GND
const int encoder_a = 2; // Green - pin 2 - Digital
const int encoder_b = 3; // White - pin 3 - Digital
volatile float encoder = 0;
float encoderCal = 0;
int LED = 13;
char incomingByte = 0;
String command;
String encoderString = "0";
unsigned long EresetVector = 0;

void setup() {
  Serial.begin(9600);
  Serial1.begin(9600);
  pinMode(encoder_a, INPUT_PULLUP);
  pinMode(encoder_b, INPUT_PULLUP);

  attachInterrupt(0, encoderPinChangeA, CHANGE);
  attachInterrupt(1, encoderPinChangeB, CHANGE);
  pinMode(LED, OUTPUT);

}

void loop() {
  if (Serial.available() > 0)
  {
    EresetVector = millis();
    SerialFunction();
    if (millis() > EresetVector + 1000)
    {
      Serial1.println("encoder error");
      return;
    }
  }
}

void encoderPinChangeA() {
  encoder += digitalRead(encoder_a) == digitalRead(encoder_b) ? -1 : 1;
  return;
}

void encoderPinChangeB() {
  encoder += digitalRead(encoder_a) != digitalRead(encoder_b) ? -1 : 1;
  return;
}



void SerialFunction() {

  if (Serial.available() > 0)       //If data is coming in, stop and do this
  {
    incomingByte = Serial.read();   //anything coming in on the serial port is set as the chacter incomingByte
    Serial1.print(incomingByte);
    if (incomingByte == '\n')       //If the user hits enter it should be a null character, meaning they're finished inputing a command
    {
      parseCommand(command);        //Go to the function parseCommand and take the string called command with you
      Serial1.print("Command = ");
      Serial1.println(command);
      command = "";                 //empty the string called command
    }
    else                            //if this is not a null character
    {
      command += incomingByte;      //add the incoming Bytes to the string "command"
    }
  }
  return;
}

void parseCommand(String com)                              //This function takes the string "command" from the main loop, parses it, and then returns two values to be used by another function called MainlineFlowRate and RequiredFlowRate
{
  String part1;                                            //String part1 is used to find which command was sent. Either MainlineFlowRate or RequiredFlowRate
  String part2;                                            //String part2 is used to find what the mainline flow rate is and what the desired flow rate is

  part1 = com.substring(0, com.indexOf(","));                            //This reads the string command and sets part1 to the first word sent be the user
  Serial1.print("part1 ");
  Serial1.println(part1);
  if (part1.equalsIgnoreCase("ER"))                        //if the command from the serial port is MainlineFlowRate set the following two digits as the MainlineFlowRate
  {
    encoderCal = (encoder*.00056112024005143959419875687647353);                              //this line converts the raw encoder value to feet. Just run the lateral for a certain distacne and then dived the distance it went by the encoder value to get a calabration value.
    encoderString = ("ER,");
    encoderString = (encoderString + encoderCal);
    Serial.println(encoderString);                              //set the 2 digits following the word MainlineFlowRate (part2) as the global integer MainlineFlowRate
    Serial1.println("encoder String");                              //set the 2 digits following the word MainlineFlowRate (part2) as the global integer MainlineFlowRate
    Serial1.println(encoderString);                              //set the 2 digits following the word MainlineFlowRate (part2) as the global integer MainlineFlowRate
    encoderString = ("");
  }
}