#include <Wire.h>

double VOLTAGE, P100, P150;
double temp, load = 0;
uint8_t Q100, Q150;
bool new_message = false;

void setup()
{
  Wire.begin();
  Serial.begin(9600);
  Serial.println("Enter Nominal System Voltage:");
  while (Serial.available() == 0) {;}
  VOLTAGE = Serial.parseFloat(SKIP_ALL);
  Serial.print("System Voltage: ");
  Serial.println(VOLTAGE, DEC);
  P150 = (VOLTAGE * VOLTAGE) / 150;
  P100 = (VOLTAGE * VOLTAGE) / 100;
  Serial.println("Enter Load in kW:");
}

void loop()
{
  new_message = false;
  Serial.flush();
  if (Serial.available())temp = Serial.parseFloat(SKIP_ALL) * 1000;

  if ((temp != load) && (temp > 0))
  {
    load = temp;
    if (VOLTAGE <= 500) //We don't want to use the 100ohm resistors if the voltage is higher than 500 as they would draw excessive power.
    {
      Q100 = load / P100;
      if (Q100 > 5) Q100 = 5;
      Q150 = (load - (Q100 * P100)) / P150;
    }
    else
    {
      Q150 = load / P150;
      Q100 = 0;
    }
    if (Q150 > 15) Q150 = 15;
    Serial.print("A combination of ");
    Serial.print(Q150, DEC);
    Serial.print(" 150ohm and ");
    Serial.print(Q100, DEC);
    Serial.print(" 100ohm resistors will be requested. ");
    //Serial.print(load - ((P150*Q150)+(P100*Q100)),DEC);
    Serial.print(((P150 * Q150) + (P100 * Q100)), DEC);
    Serial.println("W Accounted for.");
    new_message = true;
  }
  delay(50);
  Wire.beginTransmission(0x30); //Controller Board Has Address 0x07
  Wire.write(0x01); //First "EEPROM Address" stores resistor data.
  Wire.write((Q100 << 4) | Q150);
  Wire.endTransmission();


  if (new_message == true) {
    delay(25);
    Wire.requestFrom(0x30, 1);
    while (!Wire.available()) {;}
      int c = Wire.read();
      Serial.print("Quantity of 150Ohm: ");
      Serial.print(c & 0b00001111); //Print Q150
      Serial.print(" Quantity of 100Ohm: ");
      Serial.print((c & 0b01110000)>>4);
      Serial.println(" was recieved.");
  }
}