/*
  ============================================================
  TUGAS: Simulasi IoT ESP32 - Pertanian Presisi Berbasis Digital
  Komponen:
    - Sensor DHT22 (suhu udara)      -> pin GPIO 15
    - Potensiometer (soil moisture)   -> pin analog GPIO 34
    - Relay Pompa Air                 -> pin GPIO 26
  Logika:
    - Jika soil_moisture_percent < 40% -> Relay ON  (pompa nyala)
    - Jika soil_moisture_percent >= 40% -> Relay OFF (pompa mati)
  Output:
    - JSON payload ke Serial Monitor setiap 2 detik
  ============================================================
*/

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

// ---------- Konfigurasi Pin ----------
#define DHTPIN 15
#define DHTTYPE DHT22
#define SOIL_PIN 34
#define RELAY_PIN 26
// LCD I2C menggunakan pin default I2C ESP32: SDA = GPIO 21, SCL = GPIO 22

// ---------- Konfigurasi LCD ----------
LiquidCrystal_I2C lcd(0x27, 16, 2);

// ---------- Konfigurasi Logika ----------
const float SOIL_MOISTURE_THRESHOLD = 40.0;
const unsigned long INTERVAL_MS = 2000;
const float ANNUAL_RAINFALL_MM = 1200.0;

DHT dht(DHTPIN, DHTTYPE);
unsigned long lastSendTime = 0;

void setup() {
  Serial.begin(115200);
  dht.begin();

  pinMode(RELAY_PIN, OUTPUT);
  digitalWrite(RELAY_PIN, LOW);

  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Precision Farm");
  lcd.setCursor(0, 1);
  lcd.print("Initializing...");

  Serial.println("=== Sistem IoT Pertanian Presisi - ESP32 ===");
  Serial.println("Inisialisasi sensor DHT22 & Potensiometer...");
  delay(2000);
  lcd.clear();
}

void loop() {
  unsigned long currentTime = millis();

  if (currentTime - lastSendTime >= INTERVAL_MS) {
    lastSendTime = currentTime;

    float temperature = dht.readTemperature();
    float humidity = dht.readHumidity();

    if (isnan(temperature) || isnan(humidity)) {
      Serial.println("{\"error\": \"Gagal membaca sensor DHT22\"}");
      return;
    }

    int rawSoil = analogRead(SOIL_PIN);
    float soilMoisturePercent = map(rawSoil, 0, 4095, 0, 100);
    soilMoisturePercent = constrain(soilMoisturePercent, 0, 100);

    String statusPompa;
    if (soilMoisturePercent < SOIL_MOISTURE_THRESHOLD) {
      digitalWrite(RELAY_PIN, HIGH);
      statusPompa = "ON";
    } else {
      digitalWrite(RELAY_PIN, LOW);
      statusPompa = "OFF";
    }

    StaticJsonDocument<256> doc;
    doc["avg_temperature_c"] = round(temperature * 10) / 10.0;
    doc["annual_rainfall_mm"] = ANNUAL_RAINFALL_MM;
    doc["soil_moisture_percent"] = round(soilMoisturePercent * 10) / 10.0;
    doc["status_pompa"] = statusPompa;

    serializeJson(doc, Serial);
    Serial.println();

    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("T:");
    lcd.print(temperature, 1);
    lcd.print("C H:");
    lcd.print(humidity, 0);
    lcd.print("%");

    lcd.setCursor(0, 1);
    lcd.print("Soil:");
    lcd.print(soilMoisturePercent, 0);
    lcd.print("% ");
    lcd.print(statusPompa);
  }
}