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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_ADDR 0x3C
#define ONE_WIRE_BUS 32 // DS18B20 on GPIO32

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature tempSensor(&oneWire);

// Pins
const int pressureSensorPin = 34;
const int greenLedPin = 25;
const int yellowLedPin = 26;
const int redLedPin = 27;
const int buzzerPin = 14;

// Tank Parameters
const float MAX_PRESSURE = 3000.0; // psi
const float CRITICAL_PRESSURE = 500.0;
const float WARNING_PRESSURE = 1000.0;
const float CRITICAL_TEMP = 50.0; // °C (Alert if too high)

void setup() {
  Serial.begin(115200);
  
  // Initialize display
  if(!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  
  // Initialize temperature sensor
  tempSensor.begin();
  
  // Initialize pins
  pinMode(greenLedPin, OUTPUT);
  pinMode(yellowLedPin, OUTPUT);
  pinMode(redLedPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  
  // Show startup message
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0,0);
  display.println("Oxygen Tank Monitor");
  display.println("Initializing...");
  display.display();
  delay(3000);
}

void loop() {
  // Read sensors
  float pressure = readPressure();
  float temperature = readTemperature();
  
  // Determine status
  if (pressure <= CRITICAL_PRESSURE || temperature >= CRITICAL_TEMP) {
    criticalAlert();
  } else if (pressure <= WARNING_PRESSURE) {
    warningAlert();
  } else {
    normalStatus();
  }
  
  // Update display
  updateDisplay(pressure, temperature);
  
  // Print to Serial Monitor (for debugging)
  Serial.print("Pressure: ");
  Serial.print(pressure);
  Serial.print(" psi | Temp: ");
  Serial.print(temperature);
  Serial.println(" °C");
  
  delay(1000); // Update every second
}

float readPressure() {
  int sensorValue = analogRead(pressureSensorPin);
  return map(sensorValue, 0, 4095, 0, MAX_PRESSURE);
}

float readTemperature() {
  tempSensor.requestTemperatures();
  return tempSensor.getTempCByIndex(0); // °C
}

void updateDisplay(float pressure, float temp) {
  display.clearDisplay();
  display.setCursor(0,0);
  display.println("OXYGEN TANK STATUS");
  display.print("Pressure: ");
  display.print(pressure);
  display.println(" psi");
  display.print("Temp: ");
  display.print(temp);
  display.println(" C");

  
  // Add status message
  if (pressure <= CRITICAL_PRESSURE) {
    display.println("STATUS: CRITICAL!");
  } else if (pressure <= WARNING_PRESSURE) {
    display.println("STATUS: WARNING");
  } else if (temp >= CRITICAL_TEMP) {
    display.println("STATUS: OVERHEAT!");
  } else {
    display.println("STATUS: NORMAL");
  }
  
  display.display();
}

// Status indicators
void normalStatus() {
  digitalWrite(greenLedPin, HIGH);
  digitalWrite(yellowLedPin, LOW);
  digitalWrite(redLedPin, LOW);
  noTone(buzzerPin);
}

void warningAlert() {
  digitalWrite(greenLedPin, LOW);
  digitalWrite(yellowLedPin, HIGH);
  digitalWrite(redLedPin, LOW);
  tone(buzzerPin, 1000, 500); // Beep every second
}

void criticalAlert() {
  digitalWrite(greenLedPin, LOW);
  digitalWrite(yellowLedPin, LOW);
  digitalWrite(redLedPin, HIGH);
  tone(buzzerPin, 2000); // Continuous alarm
}