/*
This programme uses the 85 degree low temperature curing cycle to programme the Atmega32U4 chip on the carbon ply carbon fibre curing oven.
*/

#include <Arduino.h>
#include <U8g2lib.h>

#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif

//constructor for the OLED screen
U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE, 3, 2);

//defining the constant variables for the pins
const int relayPin = 12;
const int powerledPin = 13;
const int heaterledPin = 5;
const int programmedledPin = 10;
const int modebuttonPin = A5;
const int downbuttonPin = A4;
const int upbuttonPin = A3;
const int ThermistorPin = A1;

//turning on the power LED and programmed LED
int powerled = HIGH ;
int heaterled = LOW;
int programmedled = HIGH;
int timeMins = 0;             //current time in minutes
int timeLeft = 900;           //amount of time left in programme. 

//variables for button press/debounce
int downbuttonState;             // the current reading from the input pin
int lastdownbuttonState = LOW;   // the previous reading from the input pin
int upbuttonState;             // the current reading from the input pin
int lastupbuttonState = LOW;   // the previous reading from the input pin

// the following variables are unsigned longs because the time, measured in
// milliseconds, will quickly become a bigger number than can be stored in an int.
unsigned long lastdownDebounceTime = 0;  // the last time the output pin was toggled
unsigned long downdebounceDelay = 50;    // the debounce time; increase if the output flickers
unsigned long lastupDebounceTime = 0;  // the last time the output pin was toggled
unsigned long updebounceDelay = 50;    // the debounce time; increase if the output flickers

//set initial target temperature
int setTemp = 30;              //may need to be float in some programmes?

//set initial variables used to calculate temperature
int Vo;
float R1 = 10000;
float logR2, R2, T;
float c1 = 1.009249522e-03, c2 = 2.378405444e-04, c3 = 2.019202697e-07;
float powervoltage=5;//define the power supply voltage.

//SETUP
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);

  //Define pins to be used as output
  pinMode(relayPin,OUTPUT);
  pinMode(powerledPin,OUTPUT);
  pinMode(heaterledPin,OUTPUT);
  pinMode(programmedledPin,OUTPUT);

  //Define pins to be used as input
   pinMode(modebuttonPin,INPUT);
   pinMode(downbuttonPin,INPUT);
   pinMode(upbuttonPin,INPUT);
   pinMode(ThermistorPin, INPUT);

   //initialise the u8g2 OLED screen
  u8g2.begin();  
  //allow printing of variables on the screen
  u8g2.enableUTF8Print();
}

// the loop routine runs over and over again forever:
void loop() {
  
  digitalWrite(powerledPin,HIGH);
  digitalWrite(programmedledPin,LOW);

  int downreading = digitalRead(downbuttonPin);
  int upreading = digitalRead(upbuttonPin);

  Vo = analogRead(ThermistorPin);
  R2 = R1 * (1023.0 / (float)Vo - 1.0);
  logR2 = log(R2);
  T = (1.0 / (c1 + c2*logR2 + c3*logR2*logR2*logR2));
  T = T - 273.15;
  //T=23.5;

  //Serial.print("Temperature: "); 
  //Serial.println(T);
  
  timeMins = millis()/1000/60;
  //setTemp = 20;
    
  //Serial.println(setTemp);

      if(T<setTemp){
        digitalWrite(relayPin,HIGH);
        digitalWrite(heaterledPin,HIGH);
      }
      else {
       digitalWrite(relayPin,LOW);    
       digitalWrite(heaterledPin,LOW);
      }

      //display current and set temperatures
      u8g2.firstPage();
      do {
          u8g2.setFont(u8g2_font_ncenB10_tr);
          u8g2.drawStr(0,20,"Current: ");
          u8g2.setCursor(70, 20);
          u8g2.print(T,1);
          u8g2.drawStr(100,20,"'C");
          u8g2.drawStr(0,40,"Target: ");
          u8g2.setCursor(70, 40);
          u8g2.print(setTemp);
          u8g2.drawStr(100,40,"'C");
          //u8g2.drawStr(0,60,"Remain:");
          //u8g2.setCursor(70, 60);
          //u8g2.print(timeLeft);
          //u8g2.drawStr(100,60,"mins");
        } while (u8g2.nextPage());
        delay(40);
       
  //BUTTON PRESS SECTION
  // check to see if you just pressed the button
  // (i.e. the input went from LOW to HIGH), and you've waited long enough
  // since the last press to ignore any noise:

  // If the switch changed, due to noise or pressing:
  
  //DOWN BUTTON SECTION
  if (downreading != lastdownbuttonState) {
    // reset the debouncing timer
    lastdownDebounceTime = millis();
  }

  if ((millis() - lastdownDebounceTime) > downdebounceDelay) {
    // whatever the reading is at, it's been there for longer than the debounce
    // delay, so take it as the actual current state:

    // if the button state has changed:
    if (downreading != downbuttonState) {
      downbuttonState = downreading;
    
      // only toggle the LED if the new button state is HIGH
      if (downbuttonState == HIGH) {
        //ledState = !ledState;
        setTemp=setTemp - 1;
        //Serial.println(setTemp);
        delay(1200);
      }
    }
  }

  // set the LED:
  //digitalWrite(ledPin, ledState);

  // save the reading. Next time through the loop, it'll be the lastdownbuttonState:
  lastdownbuttonState = downreading;


////UP BUTTON STARTS HERE
  if (upreading != lastupbuttonState) {
    // reset the debouncing timer
    lastupDebounceTime = millis();
  }

  if ((millis() - lastupDebounceTime) > updebounceDelay) {
    // whatever the reading is at, it's been there for longer than the debounce
    // delay, so take it as the actual current state:

    // if the button state has changed:
    if (upreading != upbuttonState) {
      upbuttonState = upreading;
    
      // only toggle the LED if the new button state is HIGH
      if (upbuttonState == HIGH) {
        //ledState = !ledState;
        setTemp=setTemp + 1;
        //Serial.println(setTemp);
        delay(1200);
      }
    }
  }

  // set the LED:
  //digitalWrite(ledPin, ledState);
 

  // save the reading. Next time through the loop, it'll be the lastdownbuttonState:
  lastupbuttonState = upreading;
  Serial.println(T);
  //delay(500);
    
}