#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Configuration pour PCF8574 - Adresses communes: 0x27, 0x3F, 0x20, 0x38
LiquidCrystal_I2C lcd(0x27, 16, 2); // Adresse, colonnes, lignes

const int DS18B20_PIN = A0;
const int LED_PIN = 8;
const float TEMP_SEUIL = 30.0;

float temperature;
bool alarmeActive = false;

void setup() {
  // Initialisation série
  Serial.begin(9600);
  Serial.println("Systeme LM35 + LCD PCF8574");
  Serial.println("==========================");
  
  // Configuration LED
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);
  
  // Initialisation LCD avec PCF8574
  initialiserLCD();
  
  // Message de démarrage
  afficherMessageDebut();
}

void initialiserLCD() {
  // Initialiser le LCD
  lcd.init();
  
  // Activer le rétroéclairage
  lcd.backlight();
  
  // Test d'affichage
  //lcd.setCursor(0, 0);
  //lcd.print("PCF8574 LCD OK");
  //lcd.setCursor(0, 1);
  //lcd.print("Adresse: 0x27");
  
  //Serial.println("LCD PCF8574 initialise");
  //Serial.println("Adresse: 0x27");
  
  //delay(2000);
//  lcd.clear();
}
//
void loop() {
  // Lecture température
  temperature = lireTemperatureDS18B20();
  
  // Contrôle alarme
  if (temperature > TEMP_SEUIL) {
    activerAlarme();
  } else {
    desactiverAlarme();
  }
  
  // Affichage
  afficherSurLCD();
  afficherSurSerie();
  
  delay(1000);
}

float lireTemperatureDS18B20() {
  int valeurAnalogique = analogRead(DS18B20_PIN);
  float tension = valeurAnalogique * (5.0 / 1023.0);
  float temp = tension * 100.0;
  return temp;
}

void activerAlarme() {
  digitalWrite(LED_PIN, HIGH);
  alarmeActive = true;
}

void desactiverAlarme() {
  digitalWrite(LED_PIN, LOW);
  alarmeActive = false;
}

void afficherSurLCD() {
  lcd.clear();
  
  // Première ligne
  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(temperature, 1);
  lcd.print(" C");
  
  // Deuxième ligne
  lcd.setCursor(0, 1);
  if (alarmeActive) {
    lcd.print("ALARME! >30C");
  } else {
    lcd.print("Normal");
  }
}

void afficherSurSerie() {
  Serial.print("DS18B20: ");
  Serial.print(temperature, 1);
  Serial.print("C | LED: ");
  Serial.print(alarmeActive ? "ON" : "OFF");
  Serial.print(" | Seuil: ");
  Serial.print(TEMP_SEUIL, 0);
  Serial.println("C");
}

void afficherMessageDebut() {
  lcd.setCursor(0, 0);
  lcd.print("  SYSTEME DS18B20");
  lcd.setCursor(0, 1);
  lcd.print(" LCD PCF8574");
  delay(2000);
  lcd.clear();
}