/*
  Sistem Monitoring Lingkungan - ESP32
  Sensor:
   - DHT22  -> DATA pin ke GPIO 4
   - Soil moisture (potentiometer simulasi) -> AOUT ke GPIO 34 (ADC1_CH6)
   - MQ-2 analog -> AOUT ke GPIO 35 (ADC1_CH7)
   - LCD I2C (SDA=21, SCL=22) -> 16x2 LCD via I2C module

  Catatan:
   - GPIO34 & GPIO35 adalah input-only ADC pada ESP32 (baik untuk sensor analog).
   - Jika nilai soil kebalikan (putar kanan -> nilai kecil), tukar koneksi 3.3V/GND pada potentiometer.
   - Untuk Thingspeak: isi WIFI_SSID, WIFI_PASS, THINGSPEAK_API_KEY dan uncomment bagian WiFi + HTTP.
*/

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

// ===== PIN =====
#define DHT_PIN 4
#define SOIL_PIN 34     // ADC1_CH6
#define MQ2_PIN 35      // ADC1_CH7

// ===== SENSOR & LCD SETUP =====
DHTesp dht;
LiquidCrystal_I2C lcd(0x27, 16, 2); // Alamat 0x27 umum; kalau berbeda sesuaikan

// ===== Optional: Thingspeak / WiFi (uncomment jika diperlukan) =====
// #include <WiFi.h>
// #include <HTTPClient.h>
// const char* WIFI_SSID = "YOUR_SSID";
// const char* WIFI_PASS = "YOUR_PASSWORD";
// const char* THINGSPEAK_API_KEY = "YOUR_THINGSPEAK_WRITE_APIKEY";
// const char* THINGSPEAK_URL = "http://api.thingspeak.com/update";

// ===== SETTINGS =====
const unsigned long READ_INTERVAL_MS = 5000UL; // interval baca sensor dan tampil (ms)
unsigned long lastRead = 0;

void setup() {
  Serial.begin(115200);
  delay(100);

  // init sensors + lcd
  dht.setup(DHT_PIN, DHTesp::DHT22);
  lcd.init();
  lcd.backlight();

  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Starting...");
  Serial.println("Starting IoT Monitoring - ESP32");
  
  // Optional: wifi connect (uncomment to use)
  /*
  WiFi.begin(WIFI_SSID, WIFI_PASS);
  Serial.print("Connecting WiFi");
  int wl_count = 0;
  while (WiFi.status() != WL_CONNECTED && wl_count < 20) {
    delay(500);
    Serial.print(".");
    wl_count++;
  }
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println();
    Serial.print("Connected, IP: ");
    Serial.println(WiFi.localIP());
  } else {
    Serial.println();
    Serial.println("WiFi connect failed (timeout).");
  }
  */
}

float readTemperature() {
  TempAndHumidity th = dht.getTempAndHumidity();
  if (isnan(th.temperature)) return NAN;
  return th.temperature;
}

float readHumidity() {
  TempAndHumidity th = dht.getTempAndHumidity();
  if (isnan(th.humidity)) return NAN;
  return th.humidity;
}

int readSoilRaw() {
  // ADC range ESP32: 0 - 4095
  int raw = analogRead(SOIL_PIN);
  return raw;
}

int readMQ2Raw() {
  int raw = analogRead(MQ2_PIN);
  return raw;
}

void updateLCD(float temp, float hum, int soilRaw, int gasRaw) {
  // hitung persentase sensor analog -> (optional mapping)
  // Soil: 0..4095 -> 0..100% (asumsi higher = lebih lembab)
  int soilPct = map(soilRaw, 0, 4095, 0, 100);
  soilPct = constrain(soilPct, 0, 100);

  // Gas: tampilkan raw atau dalam persen
  int gasPct = map(gasRaw, 0, 4095, 0, 100);
  gasPct = constrain(gasPct, 0, 100);

  // Line 1: Temp & Humidity
  lcd.setCursor(0,0);
  if (!isnan(temp) && !isnan(hum)) {
    char buf1[17];
    // Contoh: "T:25.4C H:60%"
    snprintf(buf1, sizeof(buf1), "T:%4.1fC H:%3.0f%%", temp, hum);
    lcd.print(buf1);
  } else {
    lcd.print("T: --.-C H: --% ");
  }

  // Line 2: Soil & Gas
  lcd.setCursor(0,1);
  char buf2[17];
  // contoh: "Soil:45% Gas:12%"
  snprintf(buf2, sizeof(buf2), "Soil:%3d%% Gas:%3d%%", soilPct, gasPct);
  lcd.print(buf2);
}

void sendToThingspeak(float temp, float hum, int soilRaw, int gasRaw) {
  // Optional: kirim ke Thingspeak. Pastikan WiFi sudah connected.
  /*
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("WiFi not connected, skip Thingspeak");
    return;
  }
  HTTPClient http;
  String url = String(THINGSPEAK_URL) + "?api_key=" + THINGSPEAK_API_KEY;
  url += "&field1=" + String(temp);
  url += "&field2=" + String(hum);
  url += "&field3=" + String(soilRaw);
  url += "&field4=" + String(gasRaw);
  http.begin(url);
  int httpCode = http.GET();
  if (httpCode > 0) {
    Serial.print("Thingspeak response: ");
    Serial.println(httpCode);
  } else {
    Serial.print("Error sending to Thingspeak: ");
    Serial.println(httpCode);
  }
  http.end();
  */
}

void printSerial(float temp, float hum, int soilRaw, int gasRaw) {
  Serial.println("=== SENSOR READINGS ===");
  if (!isnan(temp)) {
    Serial.printf("Temperature: %.2f C\n", temp);
  } else {
    Serial.println("Temperature: NAN");
  }
  if (!isnan(hum)) {
    Serial.printf("Humidity   : %.2f %%\n", hum);
  } else {
    Serial.println("Humidity   : NAN");
  }
  Serial.printf("Soil Raw   : %d (0..4095)\n", soilRaw);
  Serial.printf("MQ-2 Raw   : %d (0..4095)\n", gasRaw);
  Serial.println("=======================");
}

void loop() {
  unsigned long now = millis();
  if (now - lastRead < READ_INTERVAL_MS) return;
  lastRead = now;

  // Baca sensor
  float temperature = readTemperature();
  float humidity = readHumidity();
  int soilRaw = readSoilRaw();
  int gasRaw = readMQ2Raw();

  // Serial output
  printSerial(temperature, humidity, soilRaw, gasRaw);

  // Update LCD
  updateLCD(temperature, humidity, soilRaw, gasRaw);

  // Optional: kirim ke Thingspeak
  // sendToThingspeak(temperature, humidity, soilRaw, gasRaw);
}