// --- Library yang dibutuhkan ---
#include <Wire.h>
#include "DHT.h"
#include <PID_v1.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// --- Konfigurasi Pin ---
#define DHT_PIN 4
#define RELAY_PIN 5
#define RESET_BUTTON_PIN 15   // Tombol untuk reset ke mode standar
#define SET_MODE_BUTTON_PIN 23  // <-- Tombol BARU untuk masuk ke mode potensiometer
#define BUZZER_PIN 13
#define STOP_BUZZER_PIN 14
#define POT_PIN 34

#define DHT_TYPE DHT22

// --- Konfigurasi OLED ---
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// --- Konfigurasi Sistem & Mode ---
enum ControlMode { MODE_DEFAULT, MODE_POTENTIOMETER }; // <-- Logika mode baru
ControlMode currentMode = MODE_DEFAULT;               // <-- Sistem mulai di mode default
#define DEFAULT_SETPOINT 22.0
const float ALARM_THRESHOLD = 2.0;
bool isAlarmActive = false;
bool alarmAcknowledged = false; // Variabel baru untuk mengatasi bug alarm

// --- Variabel untuk Debouncing Non-Blocking ---
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 200; // Jeda waktu untuk debounce

// Inisialisasi Perangkat & Variabel Lain
DHT dht(DHT_PIN, DHT_TYPE);
const int numReadings = 10;
float tempReadings[numReadings]; // Mengganti nama variabel agar lebih jelas
int tempReadIndex = 0;
float tempTotal = 0;
float tempAverage = 0;
float currentHumidity = 0;
double Setpoint, Input, Output;
double Kp = 50, Ki = 20, Kd = 5;
PID myPID(&Input, &Output, &Setpoint, Kp, Ki, Kd, REVERSE);
unsigned long windowSize = 5000;
unsigned long windowStartTime;

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

  // Inisialisasi Pin
  pinMode(RESET_BUTTON_PIN, INPUT_PULLUP);
  pinMode(SET_MODE_BUTTON_PIN, INPUT_PULLUP); // <-- Inisialisasi pin baru
  pinMode(STOP_BUZZER_PIN, INPUT_PULLUP);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);

  // Inisialisasi OLED
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Coba 0x3D jika gagal
    Serial.println(F("Alokasi SSD1306 gagal"));
    for(;;);
  }
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
  display.setTextSize(1);
  display.setCursor(0,0);
  display.println("Sistem Siap!");
  display.display();
  
  dht.begin();
  
  // Inisialisasi variabel filter
  for (int i = 0; i < numReadings; i++) tempReadings[i] = 0;
  
  Setpoint = DEFAULT_SETPOINT;
  windowStartTime = millis();
  myPID.SetOutputLimits(0, windowSize);
  myPID.SetMode(AUTOMATIC);
  
  delay(2000);
}

void checkButtons() {
  // Hanya proses tombol jika jeda waktu debounce sudah lewat
  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (digitalRead(RESET_BUTTON_PIN) == LOW) {
      currentMode = MODE_DEFAULT;
      Setpoint = DEFAULT_SETPOINT;
      Serial.println(">>> Tombol Reset Ditekan: Mode Standar Aktif <<<");
      lastDebounceTime = millis(); // Reset timer debounce
    }
    else if (digitalRead(SET_MODE_BUTTON_PIN) == LOW) {
      currentMode = MODE_POTENTIOMETER;
      Serial.println(">>> Tombol Set Ditekan: Mode Potensiometer Aktif <<<");
      lastDebounceTime = millis(); // Reset timer debounce
    }
    else if (digitalRead(STOP_BUZZER_PIN) == LOW) {
      isAlarmActive = false;
      alarmAcknowledged = true;
      Serial.println(">>> Tombol Stop Buzzer Ditekan <<<");
      lastDebounceTime = millis(); // Reset timer debounce
    }
  }
}

void loop() {
  // --- Proses Input ---
  checkButtons(); // <-- Panggil fungsi untuk cek tombol secara non-blocking
  
  // Hanya baca potensiometer jika dalam mode yang sesuai
  if (currentMode == MODE_POTENTIOMETER) {
    int potValue = analogRead(POT_PIN);
    Setpoint = 18.0 + ((float)potValue / 4095.0) * (30.0 - 18.0);
  }
  
  // --- Baca & Filter Sensor ---
  float rawTemp = dht.readTemperature();
  currentHumidity = dht.readHumidity(); // Membaca kelembaban
  if (!isnan(rawTemp) && !isnan(currentHumidity)) {
    tempTotal -= tempReadings[tempReadIndex];
    tempReadings[tempReadIndex] = rawTemp;
    tempTotal += tempReadings[tempReadIndex];
    tempReadIndex = (tempReadIndex + 1) % numReadings;
    tempAverage = tempTotal / numReadings;
  }
  
  Input = tempAverage;
  myPID.Compute();

  // --- Logika Alarm (Sudah diperbaiki) ---
  if (abs(Input - Setpoint) > ALARM_THRESHOLD) {
    if (!alarmAcknowledged) {
      isAlarmActive = true;
    }
  } else {
    alarmAcknowledged = false;
    isAlarmActive = false;
  }

  // --- Kontrol Buzzer & Relay ---
  if (isAlarmActive) { tone(BUZZER_PIN, 1000); } else { noTone(BUZZER_PIN); }
  
  unsigned long now = millis();
  if (now - windowStartTime > windowSize) windowStartTime += windowSize;
  digitalWrite(RELAY_PIN, (Output > now - windowStartTime));

  // --- Tampilkan Info ke OLED ---
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(0, 0);
  display.print(String(Input, 1));
  display.print((char)247);
  display.print("C");
  
  display.setTextSize(1);
  display.setCursor(90, 8);
  display.print(String(currentHumidity, 0) + "% RH"); // Menampilkan kelembaban

  display.setCursor(0, 24);
  display.print("Target: " + String(Setpoint, 1) + "C");
  if(currentMode == MODE_POTENTIOMETER) display.print(" (P)"); // Tanda mode Potensiometer
  
  display.setCursor(0, 40);
  display.print("Power Kipas: " + String(Output/windowSize*100, 0) + "%");
  
  display.setCursor(0, 54);
  if(isAlarmActive){
    display.print("Status: ! ALARM !");
  } else {
    display.print("Status: Normal");
  }
  
  display.display();
}