#include <WiFi.h>
#include <HTTPClient.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <OneWire.h>
#include <DallasTemperature.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire);

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

// ThingSpeak API details
const char* server = "https://api.thingspeak.com";
const char* apiKey = "CDJEFTTGRAFUMV67";

// Pins
#define ONE_WIRE_BUS 15
const int voltagePin = 35;
const int currentPin = 34;

// Temperature sensor
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature tempSensor(&oneWire);

float voltage, current, power, powerConsumption, temperature, costOfElectricity;
unsigned long previousMillis = 0;
unsigned long totalMillis = 0;

// Password protection
const String correctPassword = "Afeeq2002";
bool isAuthenticated = false;

// Timeout constants
const unsigned long timeoutDuration = 5 * 60 * 1000; // 5 minutes in milliseconds
const unsigned long inactivityDuration = 5 * 60 * 1000; // Inactivity timeout (5 minutes)

// Timer for inactivity
unsigned long lastActivityTime = 0;

// Function to calculate cost based on TNB tariff
float calculateCost(float powerConsumption) {
  float cost = 0.0;

  if (powerConsumption <= 200) {
    cost = powerConsumption * 0.218; // Tier 1
  } else if (powerConsumption <= 300) {
    cost = (200 * 0.218) + ((powerConsumption - 200) * 0.334); // Tier 2
  } else if (powerConsumption <= 600) {
    cost = (200 * 0.218) + (100 * 0.334) + ((powerConsumption - 300) * 0.516); // Tier 3
  } else {
    cost = (200 * 0.218) + (100 * 0.334) + (300 * 0.516) + ((powerConsumption - 600) * 0.546); // Tier 4
  }

  return cost;
}

void authenticateUser() {
  Serial.println("Enter Password:");
  String enteredPassword = "";
  unsigned long startTime = millis();

  while (!isAuthenticated) {
    if (millis() - startTime >= timeoutDuration) {
      Serial.println("Authentication timeout! Restarting system...");
      ESP.restart(); // Restart the ESP32
    }

    if (Serial.available()) {
      char c = Serial.read();
      if (c == '\n' || c == '\r') {
        if (enteredPassword == correctPassword) {
          isAuthenticated = true;
          lastActivityTime = millis(); // Reset inactivity timer
          Serial.println("Access Granted!");
          display.clearDisplay();
          display.setCursor(0, 0);
          display.println("Access Granted!");
          display.display();
          delay(1000);
        } else {
          Serial.println("Incorrect Password! Try again:");
          enteredPassword = "";
        }
      } else {
        enteredPassword += c;
      }
    }
  }
}

void connectToWiFi() {
  WiFi.begin(ssid, password);
  unsigned long startTime = millis();

  while (WiFi.status() != WL_CONNECTED) {
    if (millis() - startTime >= timeoutDuration) {
      Serial.println("WiFi connection timeout! Restarting system...");
      ESP.restart(); // Restart the ESP32
    }

    delay(1000);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected!");
  lastActivityTime = millis(); // Reset inactivity timer
}

void sendDataToThingSpeak() {
  int rawVoltage = analogRead(voltagePin);
  int rawCurrent = analogRead(currentPin);

  voltage = (rawVoltage / 4095.0) * 230;  // Assuming 230V as a reference
  float currentVoltage = (rawCurrent / 4095.0) * 5; // Assuming 5V reference
  current = currentVoltage / 0.1;  // Sensor sensitivity: 0.1V/A
  power = voltage * current;

  unsigned long currentMillis = millis();
  unsigned long elapsedTime = currentMillis - previousMillis;
  previousMillis = currentMillis;
  totalMillis += elapsedTime;

  float elapsedTimeHours = totalMillis / 3600000.0;  // Convert milliseconds to hours
  powerConsumption = (power / 1000.0) * elapsedTimeHours; // Convert power to kWh
  costOfElectricity = calculateCost(powerConsumption);  // Use TNB tariff for cost calculation

  tempSensor.requestTemperatures();
  temperature = tempSensor.getTempCByIndex(0);  // Assuming one temperature sensor

  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    String url = String(server) + "/update?api_key=" + apiKey +
                 "&field1=" + String(voltage, 2) +
                 "&field2=" + String(current, 2) +
                 "&field3=" + String(powerConsumption, 2) +
                 "&field4=" + String(temperature, 2) +
                 "&field5=" + String(costOfElectricity, 2);
    http.begin(url);
    int httpCode = http.GET();
    http.end();

    if (httpCode > 0) {
      Serial.println("Data sent to ThingSpeak successfully!");
    } else {
      Serial.println("Error sending data.");
    }
  } else {
    Serial.println("WiFi not connected!");
  }

  lastActivityTime = millis(); // Reset inactivity timer
}

void setup() {
  Serial.begin(115200);
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("OLED allocation failed");
    for (;;);
  }
  display.clearDisplay();
  display.setTextColor(WHITE);

  authenticateUser();  // Password protection
  connectToWiFi();     // Connect to WiFi

  tempSensor.begin();
  lastActivityTime = millis(); // Reset inactivity timer
}

void loop() {
  static unsigned long lastSendTime = 0;

  if (millis() - lastSendTime >= 5000) { // Send data every 5 seconds
    sendDataToThingSpeak();
    lastSendTime = millis();
  }

  // Check for inactivity timeout
  if (millis() - lastActivityTime >= inactivityDuration) {
    Serial.println("Inactivity timeout! Restarting system...");
    ESP.restart(); // Restart the ESP32
  }

  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Voltage: ");
  display.println(voltage, 2);
  display.print("Current: ");
  display.println(current, 2);
  display.print("Power (kWh): ");
  display.println(powerConsumption, 2);
  display.print("Temp: ");
  display.println(temperature, 2);
  display.print("Cost: RM ");
  display.println(costOfElectricity, 2);
  display.display();
}