/*********
  Rui Santos
  Complete project details at https://randomnerdtutorials.com
*********/

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <max6675.h>
#include <Button.h>
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define encoder0PinA 2
#define encoder0PinB 4
// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

Button targetTmpBtn(7);
int thermoDO = 4;
int thermoCS = 5;
int relayPin = 8;
int thermoCLK = 6;
int fanSpeed = 0;
int maxFanSpeed = 100;
int maxTemperature = 700;
int fanMult = 2;
bool up;
bool encChanged;
unsigned long lastTrgTmpCheck = 0;
bool checkTrgTmp = false;
//Thermal managment data
unsigned long lastLoopTime = 0;
bool isHeatingOn = true;
float targetTemp = 300;
float temp;
float tmpTargetTemp;
unsigned long lastRelayToggleTime = 0;
const unsigned long relayToggleInterval = 100; // Adjust the interval as needed

MAX6675 thermocouple(thermoCLK, thermoCS, thermoDO);

void setup() {
  Serial.begin(115200);
  targetTmpBtn.begin();
  pinMode(relayPin, OUTPUT);
  attachInterrupt (digitalPinToInterrupt (encoder0PinA), isr, CHANGE);
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3D for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }
  delay(2000);
  display.clearDisplay();

  display.setTextSize(2);
  display.setTextColor(WHITE);
  // Display static text
  display.display();
}
void isr ()
{
  if (digitalRead (encoder0PinA))
    up = digitalRead (encoder0PinB);
  else
    up = !digitalRead (encoder0PinB);
  encChanged = true;
}
bool prevHeatingState;
void loop() {
  unsigned long currentTime = millis(); // Get the current time
  updateTemp();
  isHeatingOn = (!isnan(temp)) && temp <= targetTemp;
  if (currentTime - lastRelayToggleTime >= relayToggleInterval) {
    digitalWrite(relayPin, isHeatingOn ? HIGH : LOW);
    lastRelayToggleTime = currentTime; // Update the last toggle time
  }
  if (encChanged) {
    if (checkTrgTmp) {
      if (up)
        targetTemp += fanMult;
      else
        targetTemp -= fanMult;
      lastTrgTmpCheck = currentTime;
    } else {
      if (up)
        fanSpeed += fanMult;
      else
        fanSpeed -= fanMult;
    }
    encChanged = false;
  }
  display.clearDisplay();
  display.setCursor(0, 0);

  fanSpeed = constrain(fanSpeed, 0, maxFanSpeed);
  targetTemp = constrain(targetTemp, 0, maxTemperature);
  //
  if (checkTrgTmp) {
    display.setTextSize(3);
    display.print(targetTemp, 2);
    display.println("c");
    display.setTextSize(2);
    display.print("Target");
    //display.print(thermocouple.readCelsius());

  } else {
    display.setTextSize(3);

    //display.print(thermocouple.readCelsius());
    if (isnan(temp)) {
      display.println("DISCNCT");
    } else {
      display.print(temp, 2);
      display.println("c");
    }
    display.setTextSize(2);
    display.print("Degrees");
  }
  display.println();
  display.setTextSize(2);
  display.print("Fan:");
  display.print(fanSpeed);
  display.println("%");
  display.display();

  // Calculate the elapsed time since the last loop

  if (checkTrgTmp) {
    unsigned long elapsedTrgTmpTime = currentTime - lastTrgTmpCheck;
    if (elapsedTrgTmpTime > (10 * 1000)) {
      checkTrgTmp = false;
      lastTrgTmpCheck = currentTime;
    }
  }
  if (targetTmpBtn.pressed()) {
    checkTrgTmp = !checkTrgTmp;
    if (checkTrgTmp)lastTrgTmpCheck = currentTime;
  }
  prevHeatingState = isHeatingOn;
  
  delay(50);
}
void updateTemp() {
  unsigned long currentTime = millis(); // Get the current time

  // Calculate the elapsed time since the last loop
  unsigned long elapsedTime = currentTime - lastLoopTime;
  if (elapsedTime <= 200)return;
  temp = thermocouple.readCelsius();
  //heating simulation;
  /* if (isHeatingOn) {
    temp += random(0, 5);
    } else if (temp > 0) {
    temp -= 1;
    } */
  lastLoopTime = currentTime;
}