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

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

#define NTC_PIN A0
#define REFERENCE_RES 10000.0
#define NTC_NOMINAL 10000.0
#define TEMPERATURE_NOMINAL 25.0
#define B_COEFFICIENT 3950
#define SERIES_RES 10000.0

#define TEMP_HEATING 230.0
#define TEMP_READY 280.0
#define TEMP_OVERHEAT 290.0

unsigned long startTime = 0;
unsigned long elapsedTime = 0;

// Function prototypes
void centerText(String text, int y);
void printStopwatch(unsigned long ms);
float readNTCTemp();
void startupSequence();

void centerText(String text, int y) {
  int16_t x1, y1;
    uint16_t w, h;
      display.getTextBounds(text, 0, 0, &x1, &y1, &w, &h);
        display.setCursor((SCREEN_WIDTH - w) / 2, y);
          display.println(text);
          }

          float readNTCTemp() {
            int reading = analogRead(NTC_PIN);
              float voltage = reading * (5.0 / 1024.0);
                float resistance = SERIES_RES * (5.0 / voltage - 1.0);
                  float steinhart = resistance / NTC_NOMINAL;
                    steinhart = log(steinhart);
                      steinhart /= B_COEFFICIENT;
                        steinhart += 1.0 / (TEMPERATURE_NOMINAL + 273.15);
                          steinhart = 1.0 / steinhart;
                            return steinhart - 273.15;
                            }

                            void printStopwatch(unsigned long ms) {
                              int hours = ms / 3600000;
                                int minutes = (ms / 60000) % 60;
                                  int seconds = (ms / 1000) % 60;
                                    display.setCursor(60, 55);  // Moved up slightly for better spacing
                                      if (hours < 10) display.print("0");
                                        display.print(hours);
                                          display.print(":");
                                            if (minutes < 10) display.print("0");
                                              display.print(minutes);
                                                display.print(":");
                                                  if (seconds < 10) display.print("0");
                                                    display.print(seconds);
                                                    }

                                                    void setup() {
                                                      Serial.begin(9600);
                                                        if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
                                                            Serial.println(F("SSD1306 failed"));
                                                                for(;;);
                                                                  }
                                                                    startupSequence();
                                                                      startTime = millis();
                                                                      }

                                                                      void loop() {
                                                                        float temp = readNTCTemp();
                                                                          elapsedTime = millis() - startTime;
                                                                            
                                                                              display.clearDisplay();
                                                                                display.setTextSize(1);
                                                                                  display.setTextColor(SSD1306_WHITE);
                                                                                    centerText("XAVA FOGGER 2000", 2);
                                                                                      display.drawLine(0, 12, 127, 12, SSD1306_WHITE);
                                                                                        
                                                                                          display.setTextSize(2);
                                                                                            String tempStr = String(temp, 1) + "C";
                                                                                              centerText(tempStr, 22);
                                                                                                
                                                                                                  // Heater temperature status
                                                                                                    display.setTextSize(1);
                                                                                                      display.setCursor(0, 45);
                                                                                                        String status;
                                                                                                          if (temp < TEMP_HEATING) status = "STATUS: HEATING";
                                                                                                            else if (temp < TEMP_READY) status = "STATUS: READY";
                                                                                                              else if (temp >= TEMP_OVERHEAT) status = "STATUS: OVERHEAT!";
                                                                                                                else status = "STATUS: COOLING";
                                                                                                                  display.println(status);
                                                                                                                    
                                                                                                                      // Operation time below heater status
                                                                                                                        display.setCursor(0, 55);
                                                                                                                          display.print("OPERATION:");
                                                                                                                            printStopwatch(elapsedTime);
                                                                                                                              
                                                                                                                                display.display();
                                                                                                                                  delay(100);
                                                                                                                                  }

                                                                                                                                  void startupSequence() {
                                                                                                                                    display.clearDisplay();
                                                                                                                                      display.setTextSize(1.7);
                                                                                                                                        display.setTextColor(SSD1306_WHITE);
                                                                                                                                          centerText("Booting XAVA", 28);
                                                                                                                                            display.display();
                                                                                                                                              delay(1000);
                                                                                                                                                
                                                                                                                                                  display.clearDisplay();
                                                                                                                                                    display.setTextSize(4);
                                                                                                                                                      centerText("XAVA", 20);
                                                                                                                                                        display.display();
                                                                                                                                                          delay(2000);
                                                                                                                                                            
                                                                                                                                                              String checks[] = {"Power: Normal", "Heater:Normal", "RGB:   Normal", "Laser: Normal"};
                                                                                                                                                                for (int i = 0; i < 4; i++) {
                                                                                                                                                                    display.clearDisplay();
                                                                                                                                                                        display.setTextSize(2);
                                                                                                                                                                            centerText("XAVA", 5);
                                                                                                                                                                                display.setTextSize(1.5);
                                                                                                                                                                                    display.setCursor(20, 25);
                                                                                                                                                                                        display.println("Machine Check:");
                                                                                                                                                                                            for (int j = 0; j <= i; j++) {
                                                                                                                                                                                                  display.setCursor(10, 36 + j*7);
                                                                                                                                                                                                        display.println(checks[j]);
                                                                                                                                                                                                            }
                                                                                                                                                                                                                display.display();
                                                                                                                                                                                                                    delay(1500);
                                                                                                                                                                                                                      }
                                                                                                                                                                                                                        
                                                                                                                                                                                                                          display.clearDisplay();
                                                                                                                                                                                                                            display.setTextSize(2);
                                                                                                                                                                                                                              centerText("MACHINE", 20);
                                                                                                                                                                                                                                centerText("READY", 35);
                                                                                                                                                                                                                                  display.display();
                                                                                                                                                                                                                                    delay(1000);
                                                                                                                                                                                                                                    }