#include <Arduino.h>
#include <HX711.h>
#include <Wire.h>
#include <RTClib.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <WiFi.h>
#include <HTTPClient.h>

// Pin Definitions
const int HX711_DT = 19;
const int HX711_SCK = 18;
const int BUZZER_PIN = 14;
const int LED1_PIN = 33;
const int LED2_PIN = 32;
const int BUTTON_PIN = 15;

// Display Settings
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_ADDR 0x3C
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Sensor Objects
HX711 scale;
RTC_DS3231 rtc;

// WiFi Credentials
const char* ssid = "Wokwi-GUEST";  // Default Wokwi WiFi
const char* password = "";

// CallMeBot API
const String phoneNumber = "YOUR_PHONE_NUMBER";  // Format: +628123456789
const String apiKey = "YOUR_API_KEY";

// Calibration Constants
const float EMPTY_WEIGHT = 50.0;   // Berat gelas kosong (gram)
const float TARGET_VOLUME = 240.0; // Volume target (ml)
const float MAX_VOLUME = 300.0;    // Volume maksimum (ml)
const float ML_PER_GRAM = 1.0;     // Konversi gram ke ml

// System Variables
unsigned long lastDrinkTime = 0;
bool alarmActive = false;
bool glassPlaced = true;
float currentVolume = 0;
bool systemStarted = false;
bool hardwareError = false;

void setup() {
  Serial.begin(115200);
  
  // Initialize GPIO
  pinMode(LED1_PIN, OUTPUT);
  pinMode(LED2_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  
  // Initialize I2C
  Wire.begin();
  
  // Initialize Display
  if(!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
    Serial.println("SSD1306 allocation failed");
    hardwareError = true;
  }
  
  // Initialize RTC
  if (!rtc.begin()) {
    Serial.println("Couldn't find RTC");
    updateDisplay("RTC Error", "Check connection");
    hardwareError = true;
  }
  
  // Initialize Scale
  scale.begin(HX711_DT, HX711_SCK);
  scale.set_scale();
  scale.tare();
  
  // Show boot message
  updateDisplay("System Boot", "Press button");
  
  // Wait for button press
  while (digitalRead(BUTTON_PIN) == HIGH) {
    delay(100);
  }
  
  // Connect to WiFi
  connectToWiFi();
  
  // Calibrate scale
  calibrateScale();
  
  // Set initial time
  lastDrinkTime = millis();
  systemStarted = true;
  updateDisplay("System Ready", "Waiting...");
}

void loop() {
  if (!systemStarted || hardwareError) return;
  
  unsigned long currentTime = millis();
  
  // Read current volume
  currentVolume = getCurrentVolume();
  
  // Check water level
  checkWaterLevel(currentVolume);
  
  // Check if glass is present
  bool glassDetected = (currentVolume > 10.0);
  
  // Drink reminder logic (2 minutes for simulation)
  if (currentTime - lastDrinkTime >= 120000) { // 2 menit = 120,000 ms
    if (!alarmActive) {
      // Activate alarm
      alarmActive = true;
      activateAlarm(true);
      sendWhatsApp("Waktunya minum air! Silakan ambil gelas Anda.");
      updateDisplay("Beep Beep", "Minum sayangg :)");
    }
    
    // Check if glass has been taken
    if (glassDetected) {
      // Glass still present, keep alarming
      activateAlarm(true);
    } else {
      // Glass taken, deactivate alarm
      alarmActive = false;
      activateAlarm(false);
      lastDrinkTime = currentTime;
      
      // Show thank you message
      updateDisplay("Sudah diminum?", "Muach!");
      delay(5000);
      
      // Ask to place glass again
      updateDisplay("Taruh gelasnya", "lagi yaa :)");
      
      // Wait until glass is placed again
      while (getCurrentVolume() < 10.0) {
        delay(1000);
      }
      updateDisplay("Terima kasih", "Sistem aktif");
    }
  } else {
    // Normal operation, update display
    char volumeStr[20];
    snprintf(volumeStr, 20, "Volume: %.1f ml", currentVolume);
    updateDisplay("Smart Glass", volumeStr);
  }
  
  delay(1000);
}

void connectToWiFi() {
  updateDisplay("Connecting to", "WiFi...");
  WiFi.begin(ssid, password);
  
  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 20) {
    delay(500);
    Serial.print(".");
    attempts++;
  }
  
  if (WiFi.status() == WL_CONNECTED) {
    updateDisplay("WiFi Connected", "IP: " + WiFi.localIP().toString());
    Serial.println("WiFi connected");
    delay(2000);
  } else {
    updateDisplay("WiFi Failed", "Using offline");
    Serial.println("WiFi connection failed");
    delay(2000);
  }
}

void updateDisplay(String line1, String line2) {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println(line1);
  display.setCursor(0, 20);
  display.println(line2);
  display.display();
}

void activateAlarm(bool activate) {
  static unsigned long lastBlink = 0;
  static bool ledState = false;
  
  if (activate) {
    unsigned long currentMillis = millis();
    if (currentMillis - lastBlink > 100) { // Blink every 100ms
      ledState = !ledState;
      digitalWrite(LED1_PIN, ledState);
      digitalWrite(LED2_PIN, !ledState);
      digitalWrite(BUZZER_PIN, ledState);
      lastBlink = currentMillis;
    }
  } else {
    digitalWrite(LED1_PIN, LOW);
    digitalWrite(LED2_PIN, LOW);
    digitalWrite(BUZZER_PIN, LOW);
  }
}

void sendWhatsApp(String message) {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("Cannot send WhatsApp: No WiFi");
    return;
  }

  String url = "https://api.callmebot.com/whatsapp.php?phone=" + phoneNumber + 
               "&text=" + urlEncode(message) + 
               "&apikey=" + apiKey;
  
  HTTPClient http;
  http.begin(url);
  int httpCode = http.GET();
  
  if (httpCode == HTTP_CODE_OK) {
    Serial.println("WhatsApp sent successfully");
  } else {
    Serial.printf("WhatsApp failed, error: %d\n", httpCode);
  }
  http.end();
}

String urlEncode(String str) {
  String encodedString = "";
  char c;
  for (int i = 0; i < str.length(); i++) {
    c = str.charAt(i);
    if (isalnum(c) || c == '-' || c == '_' || c == '.' || c == '~') {
      encodedString += c;
    } else if (c == ' ') {
      encodedString += "%20";
    } else {
      encodedString += '%';
      char hex = (c >> 4) & 0x0F;
      encodedString += (hex < 10) ? hex + '0' : hex + 'A' - 10;
      hex = c & 0x0F;
      encodedString += (hex < 10) ? hex + '0' : hex + 'A' - 10;
    }
  }
  return encodedString;
}

float getCurrentVolume() {
  // Read the scale (average 5 readings)
  float weight = scale.get_units(5);
  
  // If weight is less than empty weight, return 0
  if (weight < EMPTY_WEIGHT) {
    return 0.0;
  }
  
  // Convert to volume: weight (grams) to ml
  float volume = (weight - EMPTY_WEIGHT) * ML_PER_GRAM;
  return volume;
}

void checkWaterLevel(float volume) {
  if (volume > 0 && volume < TARGET_VOLUME) {
    char msg[20];
    snprintf(msg, 20, "Hanya %.1f ml", volume);
    updateDisplay("Belum penuh!", msg);
    delay(3000);
  } else if (volume > MAX_VOLUME) {
    char msg[20];
    snprintf(msg, 20, "%.1f ml!", volume);
    updateDisplay("Kebanyakan coy", msg);
    delay(3000);
  }
}

void calibrateScale() {
  updateDisplay("Calibrating", "Remove weight");
  delay(3000);
  
  // Tare the scale
  scale.tare();
  
  updateDisplay("Place 240ml", "water...");
  delay(5000); // Wait for user to place water
  
  // Read the current value
  float reading = scale.get_units(10);
  float scaleFactor = reading / TARGET_VOLUME;
  scale.set_scale(scaleFactor);
  
  char msg[30];
  snprintf(msg, 30, "Calibrated: %.2f", scaleFactor);
  updateDisplay("Calibration OK", msg);
  delay(3000);
}