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

// OLED Configuration
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_ADDR 0x3C  // Correct I2C address for the OLED
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// PIR Sensor Configuration
#define PIR_PIN 12  // PIR sensor connected to GPIO12 
bool motionDetected = false;  // To track motion state

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

// ThingSpeak Configuration
const char* server = "https://api.thingspeak.com/update?api_key=JG772FC2J98MQZXK&field1=0";
const char* apiKey = "JG772FC2J98MQZXK";

// User credentials
const String validUsername = "admin";
const String validPassword = "1234";

// Login flag and session timeout
bool isLoggedIn = false;
unsigned long lastActivityTime = 0;            // Last activity time (millis)
const unsigned long sessionTimeout = 300000;  // Timeout duration: 5 minutes

// Mock temperature and humidity values
float temperature = 25.0;  // Set a constant value or simulate changes
float humidity = 50.0;     // Set a constant value or simulate changes

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

  // Initialize PIR sensor pin
  pinMode(PIR_PIN, INPUT);

  // Initialize OLED
  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) { // Correct initialization
    Serial.println("OLED initialization failed!");
    while (true);
  }
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);

  // Display welcome message
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("Welcome! Please log in:");
  display.display();

  // Connect to WiFi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi!");
}

void loop() {
  if (!isLoggedIn) {
    // Check for login input via Serial Monitor
    if (Serial.available()) {
      String input = Serial.readStringUntil('\n');
      handleLogin(input);
    }
  } else {
    // Check for session expiry
    if (millis() - lastActivityTime > sessionTimeout) {
      isLoggedIn = false;
      display.clearDisplay();
      display.setTextSize(1);
      display.setCursor(0, 0);
      display.println("Session expired.");
      display.println("Please log in again.");
      display.display();
      Serial.println("Session expired. Logged out.");
      return;
    }

    // Read PIR sensor to detect motion
    motionDetected = digitalRead(PIR_PIN);

    // Display temperature and motion detection on the OLED
    displaySensorData();

    // Send data to ThingSpeak
    sendDataToThingSpeak();

    delay(2000);  // Refresh every 2 seconds
  }
}

// Handle login
void handleLogin(String input) {
  if (input.startsWith("POST /login")) {
    // Parse username and password
    int usernameIndex = input.indexOf("username=");
    int passwordIndex = input.indexOf("password=");
    String username = input.substring(usernameIndex + 9, input.indexOf('&', usernameIndex));
    String password = input.substring(passwordIndex + 9);

    if (username == validUsername && password == validPassword) {
      isLoggedIn = true;
      lastActivityTime = millis();  // Reset activity timer
      display.clearDisplay();
      display.setTextSize(1);
      display.setCursor(0, 0);
      display.println("Login successful!");
      display.println("Fetching data...");
      display.display();
      Serial.println("Login successful!");
    } else {
      Serial.println("Invalid credentials! Try again.");
    }
  }
}

// Display temperature, humidity, and motion status
void displaySensorData() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("Battery Temperature & Humidity:");
  display.setTextSize(2);
  display.setCursor(0, 16);
  display.print(temperature);
  display.print(" C");
  display.setCursor(0, 40);
  display.print(humidity);
  display.print(" %");

  // Display PIR motion detection result
  display.setTextSize(1);
  display.setCursor(0, 56);
  if (motionDetected) {
    display.println("Solar Detected!");
  } else {
    display.println("No Solar.");
  }

  display.display();

  // Update the activity timer
  lastActivityTime = millis();
}

// Send data to ThingSpeak
void sendDataToThingSpeak() {
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    String url = String(server) + "?api_key=" + apiKey 
                 + "&field1=" + String(temperature)
                 + "&field2=" + String(humidity)
                 + "&field3=" + String(motionDetected ? 1 : 0);
    http.begin(url);
    int httpResponseCode = http.GET();
    if (httpResponseCode > 0) {
      Serial.println("Data sent to ThingSpeak: " + url);
    } else {
      Serial.println("Error sending data to ThingSpeak.");
    }
    http.end();
  } else {
    Serial.println("WiFi not connected!");
  }
}