#include <DHT.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <ESP32Servo.h>
#include <WiFi.h>
#include <PubSubClient.h>

// --- PINS ---
#define DHT_PIN     4
#define CO2_PIN     34
#define LDR_PIN     35
#define PIR_PIN     27
#define SERVO_PIN   18
#define LED_RED     25
#define LED_GREEN   26
#define DHT_TYPE    DHT22

// --- WiFi spécial Wokwi ---
const char* ssid     = "Wokwi-GUEST";
const char* password = ""; // Laissez vide
// --- MQTT ---
const char* mqtt_server = "broker.hivemq.com";
WiFiClient espClient;
PubSubClient mqttClient(espClient);

// --- Objets ---
DHT dht(DHT_PIN, DHT_TYPE);
LiquidCrystal_I2C lcd(0x27, 16, 2);
Servo windowServo;

// --- Historique CO2 ---
float co2History[10];
int   histIndex = 0;
bool  histFull  = false;

// ─────────────────────────────────────────
//  RECONNEXION WIFI (appelée si déconnecté)
// ─────────────────────────────────────────
void reconnectWiFi() {
  if (WiFi.status() == WL_CONNECTED) return; // déjà connecté → rien à faire

  Serial.println("WiFi perdu, reconnexion...");
  WiFi.disconnect();
  delay(500);
  WiFi.begin(ssid, password);

  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 20) {
    delay(500);
    attempts++;
    Serial.print(".");
  }

  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("\nWiFi reconnecte!");
  } else {
    Serial.println("\nWiFi echec reconnexion");
  }
}

// ─────────────────────────────────────────
//  RECONNEXION MQTT (appelée si déconnecté)
// ─────────────────────────────────────────
void reconnectMQTT() {
  if (mqttClient.connected()) return; // déjà connecté → rien à faire
  if (WiFi.status() != WL_CONNECTED) return; // pas de WiFi → impossible

  Serial.println("MQTT perdu, reconnexion...");
  int attempts = 0;
  while (!mqttClient.connected() && attempts < 5) {
    // Génère un ID unique pour éviter les conflits
    String clientId = "SmartClass_" + String(random(0xffff), HEX);
    if (mqttClient.connect(clientId.c_str())) {
      Serial.println("MQTT reconnecte!");
    } else {
      Serial.print("MQTT echec code=");
      Serial.println(mqttClient.state());
      delay(1000);
      attempts++;
    }
  }
}

// ─────────────────────────────────────────
//  SCORE COGNITIF
// ─────────────────────────────────────────
int computeScore(float temp, float co2_ppm, float lux, bool presence) {
  int score = 100;
  if (temp < 18 || temp > 26)      score -= 30;
  else if (temp < 20 || temp > 24) score -= 15;
  if      (co2_ppm > 2000) score -= 40;
  else if (co2_ppm > 1500) score -= 25;
  else if (co2_ppm > 1000) score -= 10;
  if      (lux < 100) score -= 20;
  else if (lux < 200) score -= 10;
  if (!presence) score = max(score, 60);
  return max(0, min(100, score));
}

// ─────────────────────────────────────────
//  PRÉDICTION CO2
// ─────────────────────────────────────────
bool predictCO2Rise() {
  if (!histFull && histIndex < 3) return false;
  int count = histFull ? 10 : histIndex;
  float recent = co2History[(histIndex - 1 + 10) % 10];
  float older  = co2History[(histIndex - min(count, 5) + 10) % 10];
  return (recent - older) > 100;
}

// ─────────────────────────────────────────
//  SETUP
// ─────────────────────────────────────────
void setup() {
  Serial.begin(115200);
  dht.begin();
  lcd.init();
  lcd.backlight();
  windowServo.attach(SERVO_PIN);
  windowServo.write(0);
  pinMode(PIR_PIN,   INPUT);
  pinMode(LED_RED,   OUTPUT);
  pinMode(LED_GREEN, OUTPUT);

  // Message démarrage LCD
  lcd.setCursor(0, 0);
  lcd.print("Smart Classroom");
  lcd.setCursor(0, 1);
  lcd.print("Connexion...");

  // Connexion WiFi initiale
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  Serial.print("Connexion WiFi");
  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 30) {
    delay(500);
    Serial.print(".");
    attempts++;
  }

  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("\nWiFi OK: " + WiFi.localIP().toString());
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("WiFi OK!");
    lcd.setCursor(0, 1);
    lcd.print(WiFi.localIP());
    delay(2000);
  }

  // Connexion MQTT initiale
  mqttClient.setServer(mqtt_server, 1883);
  reconnectMQTT();

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Smart Classroom");
  lcd.setCursor(0, 1);
  lcd.print("Pret !");
  delay(1000);
}

// ─────────────────────────────────────────
//  LOOP
// ─────────────────────────────────────────
void loop() {

  // ── Vérification et reconnexion automatique ──
  reconnectWiFi();
  reconnectMQTT();
  mqttClient.loop();

  // ── Lecture capteurs ──
  float temp = dht.readTemperature();
  float hum  = dht.readHumidity();
  if (isnan(temp)) temp = 22.0;
  if (isnan(hum))  hum  = 50.0;

  float co2_ppm = map(analogRead(CO2_PIN), 0, 4095, 400, 3000);
  float lux     = map(analogRead(LDR_PIN), 0, 4095, 0, 1000);
  bool  presence = digitalRead(PIR_PIN);

  // ── Historique CO2 ──
  co2History[histIndex] = co2_ppm;
  histIndex = (histIndex + 1) % 10;
  if (histIndex == 0) histFull = true;

  // ── Score et prédiction ──
  int  score      = computeScore(temp, co2_ppm, lux, presence);
  bool risingCO2  = predictCO2Rise();
  bool openWindow = (co2_ppm > 1000) || risingCO2;
  bool alert      = (score < 50);

  // ── Actionneurs ──
  windowServo.write(openWindow ? 90 : 0);
  digitalWrite(LED_GREEN, score >= 70 ? HIGH : LOW);
  digitalWrite(LED_RED,   alert       ? HIGH : LOW);

  // ── LCD ──
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Score:");
  lcd.print(score);
  lcd.print(risingCO2 ? "% PRED!" : "% OK   ");
  lcd.setCursor(0, 1);
  lcd.print("T:");
  lcd.print((int)temp);
  lcd.print("C CO2:");
  lcd.print((int)co2_ppm);

  // ── Serial Monitor ──
  Serial.print("WiFi:");
  Serial.print(WiFi.status() == WL_CONNECTED ? "OK" : "KO");
  Serial.print(" MQTT:");
  Serial.print(mqttClient.connected() ? "OK" : "KO");
  Serial.print(" Score="); Serial.print(score);
  Serial.print(" CO2=");   Serial.print(co2_ppm);
  Serial.print(" Temp=");  Serial.println(temp);

  // ── Publication MQTT ──
  if (mqttClient.connected()) {
    char buf[10];
    sprintf(buf, "%d", score);
    mqttClient.publish("smartclass/score", buf);

    sprintf(buf, "%.1f", temp);
    mqttClient.publish("smartclass/temperature", buf);

    sprintf(buf, "%.0f", co2_ppm);
    mqttClient.publish("smartclass/co2", buf);

    sprintf(buf, "%.0f", lux);
    mqttClient.publish("smartclass/luminosite", buf);

    mqttClient.publish("smartclass/fenetre",    openWindow ? "1" : "0");
    mqttClient.publish("smartclass/prediction", risingCO2  ? "1" : "0");
  }

  delay(2000);
}