/*
  BluEcoInVET Smart Water / Digital Twin Demonstrator
  Wokwi ESP32 -> Firebase Realtime Database -> Web Dashboard

  Hardware:
  - ESP32 DevKit C v4
  - DHT22 data: GPIO 15
  - Water-level potentiometer signal: GPIO 34
  - Turbidity potentiometer signal: GPIO 35

  Security note:
  No Gemini/API key is stored on the ESP32 or in this public project.
*/

#include <WiFi.h>
#include <HTTPClient.h>
#include <WiFiClientSecure.h>
#include <DHTesp.h>

constexpr uint8_t DHT_PIN = 15;
constexpr uint8_t WATER_LEVEL_PIN = 34;
constexpr uint8_t TURBIDITY_PIN = 35;
constexpr unsigned long SEND_INTERVAL_MS = 5000;

const char* WIFI_SSID = "Wokwi-GUEST";
const char* WIFI_PASSWORD = "";

const char* FIREBASE_DATABASE_URL =
  "https://studio-2928557024-15735-default-rtdb.firebaseio.com";
const char* FIREBASE_DEVICE_PATH =
  "/bluecoinvet/devices/esp32_wokwi_01/latest.json";

DHTesp dhtSensor;
unsigned long lastSendAt = 0;

void connectToWiFi() {
  if (WiFi.status() == WL_CONNECTED) {
    return;
  }

  Serial.print("Connecting to Wokwi WiFi");
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD, 6);

  unsigned long startedAt = millis();
  while (WiFi.status() != WL_CONNECTED && millis() - startedAt < 15000) {
    delay(300);
    Serial.print(".");
  }

  if (WiFi.status() == WL_CONNECTED) {
    Serial.println();
    Serial.print("WiFi connected. IP: ");
    Serial.println(WiFi.localIP());
  } else {
    Serial.println();
    Serial.println("WiFi connection timed out. Retrying later.");
  }
}

String classifyWaterQuality(float turbidityNtu) {
  if (turbidityNtu < 5.0) {
    return "GOOD";
  }
  if (turbidityNtu < 50.0) {
    return "MODERATE";
  }
  return "POOR";
}

bool sendToFirebase(const String& payload) {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("Firebase skipped: WiFi is offline.");
    return false;
  }

  WiFiClientSecure secureClient;
  secureClient.setInsecure();

  HTTPClient http;
  String endpoint = String(FIREBASE_DATABASE_URL) + FIREBASE_DEVICE_PATH;

  if (!http.begin(secureClient, endpoint)) {
    Serial.println("Firebase error: HTTPS connection could not start.");
    return false;
  }

  http.setTimeout(12000);
  http.addHeader("Content-Type", "application/json");

  int httpCode = http.PUT(payload);
  String response = http.getString();

  Serial.print("Firebase HTTP status: ");
  Serial.println(httpCode);

  if (response.length() > 0) {
    Serial.print("Firebase response: ");
    Serial.println(response);
  }

  http.end();
  return httpCode >= 200 && httpCode < 300;
}

void setup() {
  Serial.begin(115200);
  delay(500);

  Serial.println();
  Serial.println("============================================");
  Serial.println(" BluEcoInVET Smart Water Digital Twin");
  Serial.println(" Wokwi ESP32 + Firebase RTDB");
  Serial.println("============================================");

  analogReadResolution(12);
  pinMode(WATER_LEVEL_PIN, INPUT);
  pinMode(TURBIDITY_PIN, INPUT);
  dhtSensor.setup(DHT_PIN, DHTesp::DHT22);

  connectToWiFi();
}

void loop() {
  if (millis() - lastSendAt < SEND_INTERVAL_MS) {
    delay(50);
    return;
  }
  lastSendAt = millis();

  connectToWiFi();

  TempAndHumidity climate = dhtSensor.getTempAndHumidity();
  int waterLevelRaw = analogRead(WATER_LEVEL_PIN);
  int turbidityRaw = analogRead(TURBIDITY_PIN);

  float waterLevelPct = (waterLevelRaw / 4095.0f) * 100.0f;
  float turbidityNtu = (turbidityRaw / 4095.0f) * 1000.0f;
  String waterQuality = classifyWaterQuality(turbidityNtu);

  bool climateValid =
    !isnan(climate.temperature) && !isnan(climate.humidity);

  if (!climateValid) {
    Serial.println("DHT22 read failed. Sending null values for safe JSON.");
  }

  String temperatureJson =
    climateValid ? String(climate.temperature, 1) : "null";
  String humidityJson =
    climateValid ? String(climate.humidity, 1) : "null";

  String payload = "{";
  payload += "\"deviceId\":\"esp32_wokwi_01\",";
  payload += "\"project\":\"BluEcoInVET\",";
  payload += "\"source\":\"Wokwi ESP32\",";
  payload += "\"sensorStatus\":\"" +
    String(climateValid ? "OK" : "DHT_ERROR") + "\",";
  payload += "\"temperatureC\":" + temperatureJson + ",";
  payload += "\"humidityPct\":" + humidityJson + ",";
  payload += "\"waterLevelPct\":" + String(waterLevelPct, 1) + ",";
  payload += "\"turbidityNtu\":" + String(turbidityNtu, 1) + ",";
  payload += "\"waterQuality\":\"" + waterQuality + "\",";
  payload += "\"waterLevelRaw\":" + String(waterLevelRaw) + ",";
  payload += "\"turbidityRaw\":" + String(turbidityRaw) + ",";
  payload += "\"localUptimeMs\":" + String(millis()) + ",";
  payload += "\"timestamp\":{\".sv\":\"timestamp\"}";
  payload += "}";

  Serial.println();
  Serial.println("--- Sensor sample ---");
  Serial.print("Temperature: ");
  Serial.print(climate.temperature, 1);
  Serial.println(" C");
  Serial.print("Humidity: ");
  Serial.print(climate.humidity, 1);
  Serial.println(" %");
  Serial.print("Water level: ");
  Serial.print(waterLevelPct, 1);
  Serial.println(" %");
  Serial.print("Turbidity: ");
  Serial.print(turbidityNtu, 1);
  Serial.println(" NTU");
  Serial.print("Water quality: ");
  Serial.println(waterQuality);
  Serial.print("JSON payload: ");
  Serial.println(payload);

  bool sent = sendToFirebase(payload);
  Serial.println(sent
    ? "Upload result: SUCCESS"
    : "Upload result: FAILED - check Firebase rules or connectivity");
}