#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <EEPROM.h>

// ===== OLED =====
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// ===== PINS =====
#define BTN_UP     7
#define BTN_DOWN   8
#define STBY_BTN   10
#define BUZZER     5
#define MOSFET     9
#define TEMP_PIN   A0

// ===== EEPROM STRUCT =====
struct Settings {
  int tip1;
  int tip2;
  int sleep;
  int selected;
};

Settings data;

// ===== VARIABLES =====
int menuIndex = 0;

int setTemp = 300;
int currentTemp = 0;

int tip1_temp = 300;
int tip2_temp = 380;
int selectedTip = 0;

// Sleep
int sleepMode = 0;
unsigned long lastActivity = 0;
bool heaterOn = true;
bool wakePressed = false;

// STBY
bool standby = false;
bool lastState = HIGH;
bool lastStandby = false;

// PID
float Kp = 5;
float output = 0;

// ===== BUZZER =====
void beep(int t)
{
  digitalWrite(BUZZER, HIGH);
  delay(t);
  digitalWrite(BUZZER, LOW);
}

// ===== TEMP READ =====
int readTemp()
{
  return map(analogRead(TEMP_PIN), 0, 1023, 20, 450);
}

// ===== SAVE EEPROM =====
void saveSettings()
{
  data.tip1 = tip1_temp;
  data.tip2 = tip2_temp;
  data.sleep = sleepMode;
  data.selected = selectedTip;

  EEPROM.put(0, data);
}

// ===== LOAD EEPROM =====
void loadSettings()
{
  EEPROM.get(0, data);

  if(data.tip1 < 150 || data.tip1 > 400) data.tip1 = 300;
  if(data.tip2 < 200 || data.tip2 > 450) data.tip2 = 400;
  if(data.sleep < 0 || data.sleep > 5) data.sleep = 0;
  if(data.selected < 0 || data.selected > 1) data.selected = 0;

  tip1_temp = data.tip1;
  tip2_temp = data.tip2;
  sleepMode = data.sleep;
  selectedTip = data.selected;

  setTemp = (selectedTip == 0) ? tip1_temp : tip2_temp;
}

// ===== SETUP =====
void setup()
{
  pinMode(BTN_UP, INPUT_PULLUP);
  pinMode(BTN_DOWN, INPUT_PULLUP);
  pinMode(STBY_BTN, INPUT_PULLUP);
  pinMode(BUZZER, OUTPUT);
  pinMode(MOSFET, OUTPUT);

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextColor(WHITE);

  display.setTextSize(2);
  display.setCursor(1,4);
  display.print("Diy Lab ");
  display.setCursor(6,25);
  display.print("Technology ");
  display.setTextSize(1);
  display.setCursor(10,50);
  display.print("DLT iv 1.0");
  display.display();

  beep(100);
  delay(400);

  loadSettings();   // 🔥 EEPROM LOAD

  lastActivity = millis();
}

// ===== LOOP =====
void loop()
{
  currentTemp = readTemp();

  // ===== STBY BUTTON =====
  bool currentState = digitalRead(STBY_BTN);
  standby = (currentState == LOW);

  if(lastState == HIGH && currentState == LOW)
  {
    beep(60);
  }
  lastState = currentState;

  // ===== STBY EXIT SAVE =====
  if(lastStandby == true && standby == false)
  {
    saveSettings();   // 🔥 SAVE HERE
    beep(80);
  }
  lastStandby = standby;

  // ================= STBY MENU =================
  if(standby)
  {
    digitalWrite(MOSFET, LOW);

    display.clearDisplay();
    display.setTextSize(3);
    display.setCursor(43,30);
    display.print("STBY");//STBY MENU
    

    if(!digitalRead(BTN_UP))
    {
      delay(200);
      beep(30);

      if(menuIndex == 0)
      {
        tip1_temp += 10;
        tip1_temp = constrain(tip1_temp,150,400);
        selectedTip = 0;
        setTemp = tip1_temp;
      }
      else if(menuIndex == 1)
      {
        tip2_temp += 10;
        tip2_temp = constrain(tip2_temp,200,450);
        selectedTip = 1;
        setTemp = tip2_temp;
      }
      else if(menuIndex == 2)
      {
        sleepMode++;
        if(sleepMode > 5) sleepMode = 0;
      }
    }

    if(!digitalRead(BTN_DOWN))
    {
      delay(200);
      beep(30);
      menuIndex++;
      if(menuIndex > 2) menuIndex = 0;
    }

    display.setTextSize(1);//new
    display.setCursor(0,3);
    display.print(menuIndex == 0 ? ">Tip1 " : " Tip1 ");
    if(selectedTip == 0) display.print(menuIndex == 0 ? "**" : "ON");

    display.setCursor(0,12);
    display.print(menuIndex == 1 ? ">Tip2 " : " Tip2 ");
    if(selectedTip == 1) display.print(menuIndex == 1 ? "**" : "ON");

    display.setCursor(0,22);
    display.print(menuIndex == 2 ? ">Sleep " : " Sleep ");

    //display.setCursor(0,35);
    //display.print("Temp:"); //abadoto use krbona
    display.setTextSize(2);
    display.setCursor(60,0);
    display.print(selectedTip == 0 ? tip1_temp : tip2_temp);

    
    display.setCursor(4,32);
    if(sleepMode == 0) display.print("OFF");
    if(sleepMode == 1) display.print("1m");
    if(sleepMode == 2) display.print("3m");
    if(sleepMode == 3) display.print("5m");
    if(sleepMode == 4) display.print("7m");
    if(sleepMode == 5) display.print("10m");

    display.display();
    return;
  }

  // ================= NORMAL BUTTON =================
  if(!standby)
  {
    if(!digitalRead(BTN_UP))
    {
      delay(200);
      beep(30);
      lastActivity = millis();

      if(selectedTip == 0)
      {
        tip1_temp += 10;
        tip1_temp = constrain(tip1_temp,150,400);
        setTemp = tip1_temp;
      }
      else
      {
        tip2_temp += 10;
        tip2_temp = constrain(tip2_temp,200,450);
        setTemp = tip2_temp;
      }
    }

    if(!digitalRead(BTN_DOWN))
    {
      delay(200);
      beep(30);
      lastActivity = millis();

      if(selectedTip == 0)
      {
        tip1_temp -= 10;
        tip1_temp = constrain(tip1_temp,150,400);
        setTemp = tip1_temp;
      }
      else
      {
        tip2_temp -= 10;
        tip2_temp = constrain(tip2_temp,200,450);
        setTemp = tip2_temp;
      }
    }
  }

  // ================= SLEEP =================
  unsigned long now = millis();
  unsigned long limit = 0;

  if(sleepMode == 1) limit = 60000;
  else if(sleepMode == 2) limit = 180000;
  else if(sleepMode == 3) limit = 300000;
  else if(sleepMode == 4) limit = 420000;
  else if(sleepMode == 5) limit = 600000;

  wakePressed = false;

  static bool lastBtnState = HIGH;
  bool currentBtnState = digitalRead(BTN_UP) && digitalRead(BTN_DOWN);

  if(lastBtnState == HIGH && currentBtnState == LOW)
  {
    wakePressed = true;
    lastActivity = millis();
  }

  lastBtnState = currentBtnState;

  if(sleepMode != 0)
  {
    if(now - lastActivity > limit)
    {
      heaterOn = false;
    }

    if(wakePressed)
    {
      heaterOn = true;
    }
  }

  // ================= PID =================
  if(heaterOn)
  {
    int error = setTemp - currentTemp;
    output = Kp * error;
    output = constrain(output, 0, 255);
    analogWrite(MOSFET, output);
  }
  else
  {
    analogWrite(MOSFET, 0);
  }

  // ================= DISPLAY =================
  display.clearDisplay();

  display.setTextSize(2);
  display.setCursor(0,0);
  display.print("Set:");//ok
  display.print(setTemp);

  display.setTextSize(1);
  display.setCursor(0,30);
  display.print("Tip:");
  display.print(selectedTip + 1);

  display.setCursor(0,20);
  display.print("Sleep:");
  if(sleepMode == 0) display.print("OFF");
  if(sleepMode == 1) display.print("1m");
  if(sleepMode == 2) display.print("3m");
  if(sleepMode == 3) display.print("5m");
  if(sleepMode == 4) display.print("7m");
  if(sleepMode == 5) display.print("10m");

  display.setTextSize(4);
  display.setCursor(50,28);
  display.print(currentTemp);

  if(!heaterOn)
  {
    display.setTextSize(1);
    display.setCursor(0,40);
    display.print("Sleeping");
  }

  display.display();
}